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-rw-r--r--src/3rdparty/libpng/ANNOUNCE96
-rw-r--r--src/3rdparty/libpng/CHANGES3253
-rw-r--r--src/3rdparty/libpng/CMakeLists.txt406
-rw-r--r--src/3rdparty/libpng/INSTALL135
-rw-r--r--src/3rdparty/libpng/LICENSE111
-rw-r--r--src/3rdparty/libpng/README205
-rw-r--r--src/3rdparty/libpng/TODO27
-rw-r--r--src/3rdparty/libpng/config.guess1501
-rw-r--r--src/3rdparty/libpng/config.h.in86
-rw-r--r--src/3rdparty/libpng/config.sub1705
-rw-r--r--src/3rdparty/libpng/configure.ac167
-rw-r--r--src/3rdparty/libpng/example.c843
-rw-r--r--src/3rdparty/libpng/libpng-manual.txt4136
-rw-r--r--src/3rdparty/libpng/libpng.35376
-rw-r--r--src/3rdparty/libpng/libpng.pc.in11
-rw-r--r--src/3rdparty/libpng/libpngpf.330
-rw-r--r--src/3rdparty/libpng/png.574
-rw-r--r--src/3rdparty/libpng/png.c2362
-rw-r--r--src/3rdparty/libpng/png.h2280
-rw-r--r--src/3rdparty/libpng/pngconf.h639
-rw-r--r--src/3rdparty/libpng/pngdebug.h157
-rw-r--r--src/3rdparty/libpng/pngerror.c447
-rw-r--r--src/3rdparty/libpng/pngget.c1032
-rw-r--r--src/3rdparty/libpng/pnginfo.h270
-rw-r--r--src/3rdparty/libpng/pnglibconf.h176
-rw-r--r--src/3rdparty/libpng/pngmem.c658
-rw-r--r--src/3rdparty/libpng/pngpread.c1854
-rw-r--r--src/3rdparty/libpng/pngpriv.h1245
-rw-r--r--src/3rdparty/libpng/pngread.c1466
-rw-r--r--src/3rdparty/libpng/pngrio.c176
-rw-r--r--src/3rdparty/libpng/pngrtran.c4224
-rw-r--r--src/3rdparty/libpng/pngrutil.c3616
-rw-r--r--src/3rdparty/libpng/pngset.c1225
-rw-r--r--src/3rdparty/libpng/pngstruct.h308
-rw-r--r--src/3rdparty/libpng/pngtest.c1787
-rw-r--r--src/3rdparty/libpng/pngtrans.c723
-rw-r--r--src/3rdparty/libpng/pngvalid.c6658
-rw-r--r--src/3rdparty/libpng/pngwio.c254
-rw-r--r--src/3rdparty/libpng/pngwrite.c1605
-rw-r--r--src/3rdparty/libpng/pngwtran.c631
-rw-r--r--src/3rdparty/libpng/pngwutil.c2948
41 files changed, 54903 insertions, 0 deletions
diff --git a/src/3rdparty/libpng/ANNOUNCE b/src/3rdparty/libpng/ANNOUNCE
new file mode 100644
index 0000000000..4a3b01888c
--- /dev/null
+++ b/src/3rdparty/libpng/ANNOUNCE
@@ -0,0 +1,96 @@
+
+Libpng 1.5.1 - February 3, 2011
+
+This is a public release of libpng, intended for use in production codes.
+
+Files available for download:
+
+Source files with LF line endings (for Unix/Linux) and with a
+"configure" script
+
+ libpng-1.5.1.tar.xz (LZMA-compressed, recommended)
+ libpng-1.5.1.tar.gz
+ libpng-1.5.1.tar.bz2
+
+Source files with CRLF line endings (for Windows), without the
+"configure" script
+
+ lpng151.7z (LZMA-compressed, recommended)
+ lpng151.zip
+
+Other information:
+
+ libpng-1.5.1-README.txt
+ libpng-1.5.1-LICENSE.txt
+
+Changes since the last public release (1.5.0):
+
+ Added description of png_set_crc_action() to the manual.
+ Added a note in the manual that the type of the iCCP profile was changed
+ from png_charpp to png_bytepp in png_get_iCCP(). Similarly,
+ it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
+ Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
+ internally happens to call it with one.
+ Fixed the failure to handle palette mapped images correctly.
+ Fixed a bug in handling of interlaced images (bero at arklinux.org).
+ Updated CMakeLists.txt (Clifford Yapp)
+ Fixed typecasting of some png_debug() statements (Cosmin)
+ Updated documentation of png_set|get_tRNS() (Thomas Klausner).
+ Mentioned in the documentation that applications must #include "zlib.h"
+ if they need access to anything in zlib.h, and that a number of
+ macros such as png_memset() are no longer accessible by applications.
+ Corrected pngvalid gamma test "sample" function to access all of the color
+ samples of each pixel, instead of sampling the red channel three times.
+ Changed variable names index, div, exp, and gamma to char_index, divisor,
+ exp_b10, and gamma_val, respectively, to avoid "shadow" warnings.
+ Prevent png_push_crc_skip() from hanging while reading an unknown chunk
+ or an over-large compressed zTXt chunk with the progressive reader.
+ Eliminated more GCC "shadow" warnings.
+ Revised png_fixed() in png.c to avoid compiler warning about reaching the
+ end without returning anything.
+ In the manual, describe the png_get_IHDR() arguments in the correct order.
+ Added const_png_structp and const_png_infop types, and used them in
+ prototypes for most png_get_*() functions.
+ Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
+ Added synopses for the IO_STATE functions and other missing synopses
+ to the manual. Removed the synopses from libpngpf.3 because they
+ were out of date and no longer useful. Better information can be
+ obtained by reading the prototypes and comments in pngpriv.h
+ Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build
+ Added a make macro DFNCPP that is a CPP that will accept the tokens in
+ a .dfn file and adds configure stuff to test for such a CPP. ./configure
+ should fail if one is not available.
+ Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace.
+ Added png_get_current_row_number and png_get_current_pass_number for the
+ benefit of the user transform callback.
+ Added png_process_data_pause and png_process_data_skip for the benefit of
+ progressive readers that need to stop data processing or want to optimize
+ skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
+ Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error.
+ pngvalid contains tests of transforms, which tests are currently disabled
+ because they are incompletely tested. gray_to_rgb was failing to expand
+ the bit depth for smaller bit depth images; this seems to be a long
+ standing error and resulted, apparently, in invalid output. The
+ documentation did not accurately describe what libpng really does when
+ converting RGB to gray.
+ Fixed incorrect examples of callback prototypes in the manual, that were
+ introduced in libpng-1.0.0.
+ In addition the order of the png_get_uint macros with respect to the
+ relevant function definitions has been reversed. This helps the
+ preprocessing of the symbol files be more robust. Furthermore, the
+ symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when
+ the library may actually be built with PNG_USE_READ_MACROS; this stops
+ the read macros interfering with the symbol file format.
+ Made the manual, synopses, and function prototypes use the function
+ argument names file_gamma, int_file_gamma, and srgb_intent consistently.
+ Changed PNG_UNUSED from "param=param;" to "(void)param;".
+ Added transform tests to pngvalid and simplified the arguments.
+ Added a request in the manual that applications do not use "png_" or
+ "PNG_" to begin any of their own symbols.
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+(subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe) or to glennrp at users.sourceforge.net
+
+Glenn R-P
diff --git a/src/3rdparty/libpng/CHANGES b/src/3rdparty/libpng/CHANGES
new file mode 100644
index 0000000000..fa5f2aae79
--- /dev/null
+++ b/src/3rdparty/libpng/CHANGES
@@ -0,0 +1,3253 @@
+#if 0
+libpng_changes(){ /*
+CHANGES - changes for libpng
+
+Version 0.2
+ added reader into png.h
+ fixed small problems in stub file
+
+Version 0.3
+ added pull reader
+ split up pngwrite.c to several files
+ added pnglib.txt
+ added example.c
+ cleaned up writer, adding a few new transformations
+ fixed some bugs in writer
+ interfaced with zlib 0.5
+ added K&R support
+ added check for 64 KB blocks for 16 bit machines
+
+Version 0.4
+ cleaned up code and commented code
+ simplified time handling into png_time
+ created png_color_16 and png_color_8 to handle color needs
+ cleaned up color type defines
+ fixed various bugs
+ made various names more consistent
+ interfaced with zlib 0.71
+ cleaned up zTXt reader and writer (using zlib's Reset functions)
+ split transformations into pngrtran.c and pngwtran.c
+
+Version 0.5
+ interfaced with zlib 0.8
+ fixed many reading and writing bugs
+ saved using 3 spaces instead of tabs
+
+Version 0.6
+ added png_large_malloc() and png_large_free()
+ added png_size_t
+ cleaned up some compiler warnings
+ added png_start_read_image()
+
+Version 0.7
+ cleaned up lots of bugs
+ finished dithering and other stuff
+ added test program
+ changed name from pnglib to libpng
+
+Version 0.71 [June, 1995]
+ changed pngtest.png for zlib 0.93
+ fixed error in libpng.txt and example.c
+
+Version 0.8
+ cleaned up some bugs
+ added png_set_filler()
+ split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
+ added #define's to remove unwanted code
+ moved png_info_init() to png.c
+ added old_size into png_realloc()
+ added functions to manually set filtering and compression info
+ changed compression parameters based on image type
+ optimized filter selection code
+ added version info
+ changed external functions passing floats to doubles (k&r problems?)
+ put all the configurable stuff in pngconf.h
+ enabled png_set_shift to work with paletted images on read
+ added png_read_update_info() - updates info structure with transformations
+
+Version 0.81 [August, 1995]
+ incorporated Tim Wegner's medium model code (thanks, Tim)
+
+Version 0.82 [September, 1995]
+ [unspecified changes]
+
+Version 0.85 [December, 1995]
+ added more medium model code (almost everything's a far)
+ added i/o, error, and memory callback functions
+ fixed some bugs (16 bit, 4 bit interlaced, etc.)
+ added first run progressive reader (barely tested)
+
+Version 0.86 [January, 1996]
+ fixed bugs
+ improved documentation
+
+Version 0.87 [January, 1996]
+ fixed medium model bugs
+ fixed other bugs introduced in 0.85 and 0.86
+ added some minor documentation
+
+Version 0.88 [January, 1996]
+ fixed progressive bugs
+ replaced tabs with spaces
+ cleaned up documentation
+ added callbacks for read/write and warning/error functions
+
+Version 0.89 [July, 1996]
+ Added new initialization API to make libpng work better with shared libs
+ we now have png_create_read_struct(), png_create_write_struct(),
+ png_create_info_struct(), png_destroy_read_struct(), and
+ png_destroy_write_struct() instead of the separate calls to
+ malloc and png_read_init(), png_info_init(), and png_write_init()
+ Changed warning/error callback functions to fix bug - this means you
+ should use the new initialization API if you were using the old
+ png_set_message_fn() calls, and that the old API no longer exists
+ so that people are aware that they need to change their code
+ Changed filter selection API to allow selection of multiple filters
+ since it didn't work in previous versions of libpng anyways
+ Optimized filter selection code
+ Fixed png_set_background() to allow using an arbitrary RGB color for
+ paletted images
+ Fixed gamma and background correction for paletted images, so
+ png_correct_palette is not needed unless you are correcting an
+ external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
+ in pngconf.h) - if nobody uses this, it may disappear in the future.
+ Fixed bug with Borland 64K memory allocation (Alexander Lehmann)
+ Fixed bug in interlace handling (Smarasderagd, I think)
+ Added more error checking for writing and image to reduce invalid files
+ Separated read and write functions so that they won't both be linked
+ into a binary when only reading or writing functionality is used
+ New pngtest image also has interlacing and zTXt
+ Updated documentation to reflect new API
+
+Version 0.90 [January, 1997]
+ Made CRC errors/warnings on critical and ancillary chunks configurable
+ libpng will use the zlib CRC routines by (compile-time) default
+ Changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
+ Added external C++ wrapper statements to png.h (Gilles Dauphin)
+ Allow PNG file to be read when some or all of file signature has already
+ been read from the beginning of the stream. ****This affects the size
+ of info_struct and invalidates all programs that use a shared libpng****
+ Fixed png_filler() declarations
+ Fixed? background color conversions
+ Fixed order of error function pointers to match documentation
+ Current chunk name is now available in png_struct to reduce the number
+ of nearly identical error messages (will simplify multi-lingual
+ support when available)
+ Try to get ready for unknown-chunk callback functions:
+ - previously read critical chunks are flagged, so the chunk handling
+ routines can determine if the chunk is in the right place
+ - all chunk handling routines have the same prototypes, so we will
+ be able to handle all chunks via a callback mechanism
+ Try to fix Linux "setjmp" buffer size problems
+ Removed png_large_malloc, png_large_free, and png_realloc functions.
+
+Version 0.95 [March, 1997]
+ Fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
+ Fixed bug in PNG file signature compares when start != 0
+ Changed parameter type of png_set_filler(...filler...) from png_byte
+ to png_uint_32
+ Added test for MACOS to ensure that both math.h and fp.h are not #included
+ Added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
+ Added "packswap" transformation, which changes the endianness of
+ packed-pixel bytes (Kevin Bracey)
+ Added "strip_alpha" transformation, which removes the alpha channel of
+ input images without using it (not necessarily a good idea)
+ Added "swap_alpha" transformation, which puts the alpha channel in front
+ of the color bytes instead of after
+ Removed all implicit variable tests which assume NULL == 0 (I think)
+ Changed several variables to "png_size_t" to show 16/32-bit limitations
+ Added new pCAL chunk read/write support
+ Added experimental filter selection weighting (Greg Roelofs)
+ Removed old png_set_rgbx() and png_set_xrgb() functions that have been
+ obsolete for about 2 years now (use png_set_filler() instead)
+ Added macros to read 16- and 32-bit ints directly from buffer, to be
+ used only on those systems that support it (namely PowerPC and 680x0)
+ With some testing, this may become the default for MACOS/PPC systems.
+ Only calculate CRC on data if we are going to use it
+ Added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
+ Added macros for simple libpng debugging output selectable at compile time
+ Removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
+ More description of info_struct in libpng.txt and png.h
+ More instructions in example.c
+ More chunk types tested in pngtest.c
+ Renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
+ png_set_<chunk>. We now have corresponding png_get_<chunk>
+ functions in pngget.c to get information in info_ptr. This isolates
+ the application from the internal organization of png_info_struct
+ (good for shared library implementations).
+
+Version 0.96 [May, 1997]
+ Fixed serious bug with < 8bpp images introduced in 0.95
+ Fixed 256-color transparency bug (Greg Roelofs)
+ Fixed up documentation (Greg Roelofs, Laszlo Nyul)
+ Fixed "error" in pngconf.h for Linux setjmp() behaviour
+ Fixed DOS medium model support (Tim Wegner)
+ Fixed png_check_keyword() for case with error in static string text
+ Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
+ Added typecasts to quiet compiler errors
+ Added more debugging info
+
+Version 0.97 [January, 1998]
+ Removed PNG_USE_OWN_CRC capability
+ Relocated png_set_crc_action from pngrutil.c to pngrtran.c
+ Fixed typecasts of "new_key", etc. (Andreas Dilger)
+ Added RFC 1152 [sic] date support
+ Fixed bug in gamma handling of 4-bit grayscale
+ Added 2-bit grayscale gamma handling (Glenn R-P)
+ Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
+ Minor corrections in libpng.txt
+ Added simple sRGB support (Glenn R-P)
+ Easier conditional compiling, e.g. define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
+ all configurable options can be selected from command-line instead
+ of having to edit pngconf.h (Glenn R-P)
+ Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
+ Added more conditions for png_do_background, to avoid changing
+ black pixels to background when a background is supplied and
+ no pixels are transparent
+ Repaired PNG_NO_STDIO behaviour
+ Tested NODIV support and made it default behaviour (Greg Roelofs)
+ Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
+ Regularized version numbering scheme and bumped shared-library major
+ version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs)
+
+Version 0.98 [January, 1998]
+ Cleaned up some typos in libpng.txt and in code documentation
+ Fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
+ Cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
+ Changed recommendation about file_gamma for PC images to .51 from .45,
+ in example.c and libpng.txt, added comments to distinguish between
+ screen_gamma, viewing_gamma, and display_gamma.
+ Changed all references to RFC1152 to read RFC1123 and changed the
+ PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
+ Added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
+ Changed srgb_intent from png_byte to int to avoid compiler bugs
+
+Version 0.99 [January 30, 1998]
+ Free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
+ Fixed a longstanding "packswap" bug in pngtrans.c
+ Fixed some inconsistencies in pngconf.h that prevented compiling with
+ PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
+ Fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
+ Changed recommendation about file_gamma for PC images to .50 from .51 in
+ example.c and libpng.txt, and changed file_gamma for sRGB images to .45
+ Added a number of functions to access information from the png structure
+ png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
+ Added TARGET_MACOS similar to zlib-1.0.8
+ Define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
+ Added type casting to all png_malloc() function calls
+
+Version 0.99a [January 31, 1998]
+ Added type casts and parentheses to all returns that return a value.(Tim W.)
+
+Version 0.99b [February 4, 1998]
+ Added type cast png_uint_32 on malloc function calls where needed.
+ Changed type of num_hist from png_uint_32 to int (same as num_palette).
+ Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
+ Renamed makefile.elf to makefile.lnx.
+
+Version 0.99c [February 7, 1998]
+ More type casting. Removed erroneous overflow test in pngmem.c.
+ Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
+ Added UNIX manual pages libpng.3 (incorporating libpng.txt) and png.5.
+
+Version 0.99d [February 11, 1998]
+ Renamed "far_to_near()" "png_far_to_near()"
+ Revised libpng.3
+ Version 99c "buffered" operations didn't work as intended. Replaced them
+ with png_memcpy_check() and png_memset_check().
+ Added many "if (png_ptr == NULL) return" to quell compiler warnings about
+ unused png_ptr, mostly in pngget.c and pngset.c.
+ Check for overlength tRNS chunk present when indexed-color PLTE is read.
+ Cleaned up spelling errors in libpng.3/libpng.txt
+ Corrected a problem with png_get_tRNS() which returned undefined trans array
+
+Version 0.99e [February 28, 1998]
+ Corrected png_get_tRNS() again.
+ Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
+ Touched up example.c to make more of it compileable, although the entire
+ file still can't be compiled (Willem van Schaik)
+ Fixed a bug in png_do_shift() (Bryan Tsai)
+ Added a space in png.h prototype for png_write_chunk_start()
+ Replaced pngtest.png with one created with zlib 1.1.1
+ Changed pngtest to report PASS even when file size is different (Jean-loup G.)
+ Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
+
+Version 0.99f [March 5, 1998]
+ Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
+ Moved makefiles into a "scripts" directory, and added INSTALL instruction file
+ Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
+ Added pointers to "note on libpng versions" in makefile.lnx and README
+ Added row callback feature when reading and writing nonprogressive rows
+ and added a test of this feature in pngtest.c
+ Added user transform callbacks, with test of the feature in pngtest.c
+
+Version 0.99g [March 6, 1998, morning]
+ Minor changes to pngtest.c to suppress compiler warnings.
+ Removed "beta" language from documentation.
+
+Version 0.99h [March 6, 1998, evening]
+ Minor changes to previous minor changes to pngtest.c
+ Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
+ and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
+ Added user transform capability
+
+Version 1.00 [March 7, 1998]
+ Changed several typedefs in pngrutil.c
+ Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
+ Replaced "while(1)" with "for(;;)"
+ Added PNGARG() to prototypes in pngtest.c and removed some prototypes
+ Updated some of the makefiles (Tom Lane)
+ Changed some typedefs (s_start, etc.) in pngrutil.c
+ Fixed dimensions of "short_months" array in pngwrite.c
+ Replaced ansi2knr.c with the one from jpeg-v6
+
+Version 1.0.0 [March 8, 1998]
+ Changed name from 1.00 to 1.0.0 (Adam Costello)
+ Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
+
+Version 1.0.0a [March 9, 1998]
+ Fixed three bugs in pngrtran.c to make gamma+background handling consistent
+ (Greg Roelofs)
+ Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
+ for major, minor, and bugfix releases. This is 10001. (Adam Costello,
+ Tom Lane)
+ Make months range from 1-12 in png_convert_to_rfc1123
+
+Version 1.0.0b [March 13, 1998]
+ Quieted compiler complaints about two empty "for" loops in pngrutil.c
+ Minor changes to makefile.s2x
+ Removed #ifdef/#endif around a png_free() in pngread.c
+
+Version 1.0.1 [March 14, 1998]
+ Changed makefile.s2x to reduce security risk of using a relative pathname
+ Fixed some typos in the documentation (Greg).
+ Fixed a problem with value of "channels" returned by png_read_update_info()
+
+Version 1.0.1a [April 21, 1998]
+ Optimized Paeth calculations by replacing abs() function calls with intrinsics
+ plus other loop optimizations. Improves avg decoding speed by about 20%.
+ Commented out i386istic "align" compiler flags in makefile.lnx.
+ Reduced the default warning level in some makefiles, to make them consistent.
+ Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
+ Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
+ Added grayscale and 16-bit capability to png_do_read_filler().
+ Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
+ too large when writing an image with bit_depth < 8 (Bob Dellaca).
+ Corrected some bugs in the experimental weighted filtering heuristics.
+ Moved a misplaced pngrutil code block that truncates tRNS if it has more
+ than num_palette entries -- test was done before num_palette was defined.
+ Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
+ Changed compiler flags in makefile.wat for better optimization
+ (Pawel Mrochen).
+
+Version 1.0.1b [May 2, 1998]
+ Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
+ Relocated the png_composite macros from pngrtran.c to png.h (Greg).
+ Added makefile.sco (contributed by Mike Hopkirk).
+ Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
+ Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
+ More work on the Paeth-filtering, achieving imperceptible speedup
+ (A Kleinert).
+ More work on loop optimization which may help when compiled with C++
+ compilers.
+ Added warnings when people try to use transforms they've defined out.
+ Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
+ Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
+
+Version 1.0.1c [May 11, 1998]
+ Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
+ filler bytes should have been 0xff instead of 0xf.
+ Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
+ Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
+ out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
+ Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
+ for consistency, in pngconf.h
+ Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
+ to remove unwanted capabilities via the compile line
+ Made some corrections to grammar (which, it's) in documentation (Greg).
+ Corrected example.c, use of row_pointers in png_write_image().
+
+Version 1.0.1d [May 24, 1998]
+ Corrected several statements that used side effects illegally in pngrutil.c
+ and pngtrans.c, that were introduced in version 1.0.1b
+ Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
+ More corrections to example.c, use of row_pointers in png_write_image()
+ and png_read_rows().
+ Added pngdll.mak and pngdef.pas to scripts directory, contributed by
+ Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
+ Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
+ Changed several loops from count-down to count-up, for consistency.
+
+Version 1.0.1e [June 6, 1998]
+ Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
+ added warnings when people try to set png_read_fn and png_write_fn in
+ the same structure.
+ Added a test such that png_do_gamma will be done when num_trans==0
+ for truecolor images that have defined a background. This corrects an
+ error that was introduced in libpng-0.90 that can cause gamma processing
+ to be skipped.
+ Added tests in png.h to include "trans" and "trans_values" in structures
+ when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
+ Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
+ Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
+ Added capability for user-provided malloc_fn() and free_fn() functions,
+ and revised pngtest.c to demonstrate their use, replacing the
+ PNGTEST_DEBUG_MEM feature.
+ Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
+
+Version 1.0.2 [June 14, 1998]
+ Fixed two bugs in makefile.bor .
+
+Version 1.0.2a [December 30, 1998]
+ Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
+ Fixed a bug in png_do_filler() that made it fail to write filler bytes in
+ the left-most pixel of each row (Kevin Bracey).
+ Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
+ in pngtest.c (Duncan Simpson).
+ Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
+ even when no tIME chunk was present in the source file.
+ Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
+ Fixed a problem in png_read_push_finish_row(), which would not skip some
+ passes that it should skip, for images that are less than 3 pixels high.
+ Interchanged the order of calls to png_do_swap() and png_do_shift()
+ in pngwtran.c (John Cromer).
+ Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
+ Changed "bad adaptive filter type" from error to warning in pngrutil.c .
+ Fixed a documentation error about default filtering with 8-bit indexed-color.
+ Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
+ (L. Peter Deutsch).
+ Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
+ Added png_get_copyright() and png_get_header_version() functions.
+ Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
+ Added information about debugging in libpng.txt and libpng.3 .
+ Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and
+ makefile.sco.
+ Removed lines after Dynamic Dependencies" in makefile.aco .
+ Revised makefile.dec to make a shared library (Jeremie Petit).
+ Removed trailing blanks from all files.
+
+Version 1.0.2a [January 6, 1999]
+ Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
+ Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
+ Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
+ Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
+ which is obsolete.
+
+Version 1.0.3 [January 14, 1999]
+ Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
+ Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
+
+Version 1.0.3a [August 12, 1999]
+ Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
+ if an attempt is made to read an interlaced image when it's not supported.
+ Added check if png_ptr->trans is defined before freeing it in pngread.c
+ Modified the Y2K statement to include versions back to version 0.71
+ Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
+ Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
+ Replaced leading blanks with tab characters in makefile.hux
+ Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
+ Changed (float)red and (float)green to (double)red, (double)green
+ in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
+ Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
+ Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
+ Updated documentation to refer to the PNG-1.2 specification.
+ Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
+ in makefile.knr, INSTALL, and README (L. Peter Deutsch)
+ Fixed bugs in calculation of the length of rowbytes when adding alpha
+ channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
+ Added function png_set_user_transform_info() to store user_transform_ptr,
+ user_depth, and user_channels into the png_struct, and a function
+ png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
+ Added function png_set_empty_plte_permitted() to make libpng useable
+ in MNG applications.
+ Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
+ Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
+ consistent with PNG-1.2, and allow variance of 500 before complaining.
+ Added assembler code contributed by Intel in file pngvcrd.c and modified
+ makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation,
+ Gilles Vollant)
+ Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
+ Added some aliases for png_set_expand() in pngrtran.c, namely
+ png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
+ (Greg Roelofs, in "PNG: The Definitive Guide").
+ Added makefile.beo for BEOS on X86, contributed by Sander Stok.
+
+Version 1.0.3b [August 26, 1999]
+ Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
+ Changed leading blanks to tabs in all makefiles.
+ Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
+ Made alternate versions of png_set_expand() in pngrtran.c, namely
+ png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
+ (Greg Roelofs, in "PNG: The Definitive Guide"). Deleted the 1.0.3a aliases.
+ Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
+ Revised calculation of num_blocks in pngmem.c to avoid a potentially
+ negative shift distance, whose results are undefined in the C language.
+ Added a check in pngset.c to prevent writing multiple tIME chunks.
+ Added a check in pngwrite.c to detect invalid small window_bits sizes.
+
+Version 1.0.3d [September 4, 1999]
+ Fixed type casting of igamma in pngrutil.c
+ Added new png_expand functions to scripts/pngdef.pas and pngos2.def
+ Added a demo read_user_transform_fn that examines the row filters in pngtest.c
+
+Version 1.0.4 [September 24, 1999]
+ Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
+ Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
+ Made several minor corrections to pngtest.c
+ Renamed the makefiles with longer but more user friendly extensions.
+ Copied the PNG copyright and license to a separate LICENSE file.
+ Revised documentation, png.h, and example.c to remove reference to
+ "viewing_gamma" which no longer appears in the PNG specification.
+ Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
+ Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
+ Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
+ assembler code) and makefile.vcwin32 (doesn't).
+ Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
+ Added a copy of pngnow.png to the distribution.
+
+Version 1.0.4a [September 25, 1999]
+ Increase max_pixel_depth in pngrutil.c if a user transform needs it.
+ Changed several division operations to right-shifts in pngvcrd.c
+
+Version 1.0.4b [September 30, 1999]
+ Added parentheses in line 3732 of pngvcrd.c
+ Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
+
+Version 1.0.4c [October 1, 1999]
+ Added a "png_check_version" function in png.c and pngtest.c that will generate
+ a helpful compiler error if an old png.h is found in the search path.
+ Changed type of png_user_transform_depth|channels from int to png_byte.
+
+Version 1.0.4d [October 6, 1999]
+ Changed 0.45 to 0.45455 in png_set_sRGB()
+ Removed unused PLTE entries from pngnow.png
+ Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
+
+Version 1.0.4e [October 10, 1999]
+ Fixed sign error in pngvcrd.c (Greg Roelofs)
+ Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
+
+Version 1.0.4f [October 15, 1999]
+ Surrounded example.c code with #if 0 .. #endif to prevent people from
+ inadvertently trying to compile it.
+ Changed png_get_header_version() from a function to a macro in png.h
+ Added type casting mostly in pngrtran.c and pngwtran.c
+ Removed some pointless "ptr = NULL" in pngmem.c
+ Added a "contrib" directory containing the source code from Greg's book.
+
+Version 1.0.5 [October 15, 1999]
+ Minor editing of the INSTALL and README files.
+
+Version 1.0.5a [October 23, 1999]
+ Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
+ Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
+ Further optimization and bugfix of pngvcrd.c
+ Revised pngset.c so that it does not allocate or free memory in the user's
+ text_ptr structure. Instead, it makes its own copy.
+ Created separate write_end_info_struct in pngtest.c for a more severe test.
+ Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
+
+Version 1.0.5b [November 23, 1999]
+ Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
+ PNG_FLAG_WROTE_tIME from flags to mode.
+ Added png_write_info_before_PLTE() function.
+ Fixed some typecasting in contrib/gregbook/*.c
+ Updated scripts/makevms.com and added makevms.com to contrib/gregbook
+ and contrib/pngminus (Martin Zinser)
+
+Version 1.0.5c [November 26, 1999]
+ Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr.
+ Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
+ accommodate making DLL's: Moved usr_png_ver from global variable to function
+ png_get_header_ver() in png.c. Moved png_sig to png_sig_bytes in png.c and
+ eliminated use of png_sig in pngwutil.c. Moved the various png_CHNK arrays
+ into pngtypes.h. Eliminated use of global png_pass arrays. Declared the
+ png_CHNK and png_pass arrays to be "const". Made the global arrays
+ available to applications (although none are used in libpng itself) when
+ PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
+ Removed some extraneous "-I" from contrib/pngminus/makefile.std
+ Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
+ Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
+
+Version 1.0.5d [November 29, 1999]
+ Add type cast (png_const_charp) two places in png.c
+ Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
+ Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
+ to applications a macro "PNG_USE_LOCAL_ARRAYS".
+ comment out (with #ifdef) all the new declarations when
+ PNG_USE_GLOBAL_ARRAYS is defined.
+ Added PNG_EXPORT_VAR macro to accommodate making DLL's.
+
+Version 1.0.5e [November 30, 1999]
+ Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
+ structure; refactored the inflate/deflate support to make adding new chunks
+ with trailing compressed parts easier in the future, and added new functions
+ png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
+ png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
+ NOTE: Applications that write text chunks MUST define png_text->lang
+ before calling png_set_text(). It must be set to NULL if you want to
+ write tEXt or zTXt chunks. If you want your application to be able to
+ run with older versions of libpng, use
+
+ #ifdef PNG_iTXt_SUPPORTED
+ png_text[i].lang = NULL;
+ #endif
+
+ Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
+ offsets (Eric S. Raymond).
+ Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
+ PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
+ macros, leaving the separate macros also available.
+ Removed comments on #endifs at the end of many short, non-nested #if-blocks.
+
+Version 1.0.5f [December 6, 1999]
+ Changed makefile.solaris to issue a warning about potential problems when
+ the ucb "ld" is in the path ahead of the ccs "ld".
+ Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
+ Added sCAL chunk support (Eric S. Raymond).
+
+Version 1.0.5g [December 7, 1999]
+ Fixed "png_free_spallettes" typo in png.h
+ Added code to handle new chunks in pngpread.c
+ Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
+ Added "translated_key" to png_text structure and png_write_iTXt().
+ Added code in pngwrite.c to work around a newly discovered zlib bug.
+
+Version 1.0.5h [December 10, 1999]
+ NOTE: regarding the note for version 1.0.5e, the following must also
+ be included in your code:
+ png_text[i].translated_key = NULL;
+ Unknown chunk handling is now supported.
+ Option to eliminate all floating point support was added. Some new
+ fixed-point functions such as png_set_gAMA_fixed() were added.
+ Expanded tabs and removed trailing blanks in source files.
+
+Version 1.0.5i [December 13, 1999]
+ Added some type casts to silence compiler warnings.
+ Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
+ Removed leading blanks from a #define in pngvcrd.c
+ Added some parameters to the new png_set_keep_unknown_chunks() function.
+ Added a test for up->location != 0 in the first instance of writing
+ unknown chunks in pngwrite.c
+ Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
+ prevent recursion.
+ Added png_free_hIST() function.
+ Various patches to fix bugs in the sCAL and integer cHRM processing,
+ and to add some convenience macros for use with sCAL.
+
+Version 1.0.5j [December 21, 1999]
+ Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
+ around buggy compilers.
+ Added new type "png_fixed_point" for integers that hold float*100000 values
+ Restored backward compatibility of tEXt/zTXt chunk processing:
+ Restored the first four members of png_text to the same order as v.1.0.5d.
+ Added members "lang_key" and "itxt_length" to png_text struct. Set
+ text_length=0 when "text" contains iTXt data. Use the "compression"
+ member to distinguish among tEXt/zTXt/iTXt types. Added
+ PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
+ The "Note" above, about backward incompatibility of libpng-1.0.5e, no
+ longer applies.
+ Fixed png_read|write_iTXt() to read|write parameters in the right order,
+ and to write the iTXt chunk after IDAT if it appears in the end_ptr.
+ Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
+ Reversed the order of trying to write floating-point and fixed-point gAMA.
+
+Version 1.0.5k [December 27, 1999]
+ Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
+ Added png_handle_as_unknown() function (Glenn)
+ Added png_free_chunk_list() function and chunk_list and num_chunk_list members
+ of png_ptr.
+ Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
+ Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
+ about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
+ Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
+ Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
+ Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
+
+Version 1.0.5l [January 1, 2000]
+ Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
+ for setting a callback function to handle unknown chunks and for
+ retrieving the associated user pointer (Glenn).
+
+Version 1.0.5m [January 7, 2000]
+ Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
+
+Version 1.0.5n [January 9, 2000]
+ Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
+ own memory for info_ptr->palette. This makes it safe for the calling
+ application to free its copy of the palette any time after it calls
+ png_set_PLTE().
+
+Version 1.0.5o [January 20, 2000]
+ Cosmetic changes only (removed some trailing blanks and TABs)
+
+Version 1.0.5p [January 31, 2000]
+ Renamed pngdll.mak to makefile.bd32
+ Cosmetic changes in pngtest.c
+
+Version 1.0.5q [February 5, 2000]
+ Relocated the makefile.solaris warning about PATH problems.
+ Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
+ Revised makefile.gcmmx
+ Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
+
+Version 1.0.5r [February 7, 2000]
+ Removed superfluous prototype for png_get_itxt from png.h
+ Fixed a bug in pngrtran.c that improperly expanded the background color.
+ Return *num_text=0 from png_get_text() when appropriate, and fix documentation
+ of png_get_text() in libpng.txt/libpng.3.
+
+Version 1.0.5s [February 18, 2000]
+ Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
+ new error handler that's planned for the next libpng release, and changed
+ example.c, pngtest.c, and contrib programs to use this macro.
+ Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
+ Fixed a bug in png_read_png() that caused it to fail to expand some images
+ that it should have expanded.
+ Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
+ in pngget.c
+ Changed the allocation of palette, history, and trans arrays back to
+ the version 1.0.5 method (linking instead of copying) which restores
+ backward compatibility with version 1.0.5. Added some remarks about
+ that in example.c. Added "free_me" member to info_ptr and png_ptr
+ and added png_free_data() function.
+ Updated makefile.linux and makefile.gccmmx to make directories conditionally.
+ Made cosmetic changes to pngasmrd.h
+ Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
+ Modified png_read_png() to allocate info_ptr->row_pointers only if it
+ hasn't already been allocated.
+
+Version 1.0.5t [March 4, 2000]
+ Changed png_jmp_env() migration aiding macro to png_jmpbuf().
+ Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
+ Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
+ PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
+ Files in contrib/gregbook were revised to use png_jmpbuf() and to select
+ a 24-bit visual if one is available, and to allow abbreviated options.
+ Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
+ Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
+
+Version 1.0.5u [March 5, 2000]
+ Simplified the code that detects old png.h in png.c and pngtest.c
+ Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
+ Increased precision of rgb_to_gray calculations from 8 to 15 bits and
+ added png_set_rgb_to_gray_fixed() function.
+ Added makefile.bc32 (32-bit Borland C++, C mode)
+
+Version 1.0.5v [March 11, 2000]
+ Added some parentheses to the png_jmpbuf macro definition.
+ Updated references to the zlib home page, which has moved to freesoftware.com.
+ Corrected bugs in documentation regarding png_read_row() and png_write_row().
+ Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
+ Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
+ revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
+
+Version 1.0.6 [March 20, 2000]
+ Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
+ Added makefile.sggcc (SGI IRIX with gcc)
+
+Version 1.0.6d [April 7, 2000]
+ Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
+ Added data_length parameter to png_decompress_chunk() function
+ Revised documentation to remove reference to abandoned png_free_chnk functions
+ Fixed an error in png_rgb_to_gray_fixed()
+ Revised example.c, usage of png_destroy_write_struct().
+ Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
+ Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
+ Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
+
+Version 1.0.6e [April 9, 2000]
+ Added png_data_freer() function.
+ In the code that checks for over-length tRNS chunks, added check of
+ info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
+ Minor revisions of libpng.txt/libpng.3.
+ Check for existing data and free it if the free_me flag is set, in png_set_*()
+ and png_handle_*().
+ Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
+ is defined.
+ Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
+ and mentioned the purposes of the two macros in libpng.txt/libpng.3.
+
+Version 1.0.6f [April 14, 2000]
+ Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
+ Add checks in png_set_text() for NULL members of the input text structure.
+ Revised libpng.txt/libpng.3.
+ Removed superfluous prototype for png_set_iTXt from png.h
+ Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
+ Changed several png_errors about malformed ancillary chunks to png_warnings.
+
+Version 1.0.6g [April 24, 2000]
+ Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
+ Relocated paragraph about png_set_background() in libpng.3/libpng.txt
+ and other revisions (Matthias Benckmann)
+ Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
+ png_ptr members to restore binary compatibility with libpng-1.0.5
+ (breaks compatibility with libpng-1.0.6).
+
+Version 1.0.6h [April 24, 2000]
+ Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
+ libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
+ This is a temporary change for test purposes.
+
+Version 1.0.6i [May 2, 2000]
+ Rearranged some members at the end of png_info and png_struct, to put
+ unknown_chunks_num and free_me within the original size of the png_structs
+ and free_me, png_read_user_fn, and png_free_fn within the original png_info,
+ because some old applications allocate the structs directly instead of
+ using png_create_*().
+ Added documentation of user memory functions in libpng.txt/libpng.3
+ Modified png_read_png so that it will use user_allocated row_pointers
+ if present, unless free_me directs that it be freed, and added description
+ of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
+ Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
+ 1.00) members of png_struct and png_info, to regain binary compatibility
+ when you define this macro. Capabilities lost in this event
+ are user transforms (new in version 1.0.0),the user transform pointer
+ (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
+ the high-level interface, and unknown chunks support (all new in 1.0.6).
+ This was necessary because of old applications that allocate the structs
+ directly as authors were instructed to do in libpng-0.88 and earlier,
+ instead of using png_create_*().
+ Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
+ can be used to detect codes that directly allocate the structs, and
+ code to check these modes in png_read_init() and png_write_init() and
+ generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
+ was not defined.
+ Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
+
+Version 1.0.6j [May 3, 2000]
+ Overloaded png_read_init() and png_write_init() with macros that convert
+ calls to png_read_init_2() or png_write_init_2() that check the version
+ and structure sizes.
+
+Version 1.0.7beta11 [May 7, 2000]
+ Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
+ which are no longer used.
+ Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
+ defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
+ is defined.
+ Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
+ overrun when old applications fill the info_ptr->text structure directly.
+ Added PNGAPI macro, and added it to the definitions of all exported functions.
+ Relocated version macro definitions ahead of the includes of zlib.h and
+ pngconf.h in png.h.
+
+Version 1.0.7beta12 [May 12, 2000]
+ Revised pngset.c to avoid a problem with expanding the png_debug macro.
+ Deleted some extraneous defines from pngconf.h
+ Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
+ Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
+ Added png_access_version_number() function.
+ Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
+ Expanded libpng.3/libpng.txt information about png_data_freer().
+
+Version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
+ Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
+ warnings instead of errors, as pngrutil.c does.
+ Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
+ will actually write IDATs.
+ Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
+ Make png_free_data() ignore its final parameter except when freeing data
+ that can have multiple instances (text, sPLT, unknowns).
+ Fixed a new bug in png_set_rows().
+ Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
+ Added png_set_invalid() function.
+ Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
+
+Version 1.0.7beta15 [May 30, 2000]
+ Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
+ fewer error messages.
+ Rearranged checks for Z_OK to check the most likely path first in pngpread.c
+ and pngwutil.c.
+ Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
+ in libpng.txt/libpng.3 the need for applications to check this.
+ Changed names of png_default_*() functions in pngtest to pngtest_*().
+ Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
+ Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
+ Set each pointer to NULL after freeing it in png_free_data().
+ Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
+ macro that conflicts with libpng's png_color_16.index. (Dimitri
+ Papadapoulos)
+ Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
+
+Version 1.0.7beta16 [June 4, 2000]
+ Revised the workaround of AIX string.h "index" bug.
+ Added a check for overlength PLTE chunk in pngrutil.c.
+ Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
+ indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
+ Added a warning in png_decompress_chunk() when it runs out of data, e.g.
+ when it tries to read an erroneous PhotoShop iCCP chunk.
+ Added PNG_USE_DLL macro.
+ Revised the copyright/disclaimer/license notice.
+ Added contrib/msvctest directory
+
+Version 1.0.7rc1 [June 9, 2000]
+ Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA (0x0400 not 0x0200)
+ Added contrib/visupng directory (Willem van Schaik)
+
+Version 1.0.7beta18 [June 23, 2000]
+ Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
+ and do not redefine PNGAPI if it is passed in via a compiler directive.
+ Revised visupng/PngFile.c to remove returns from within the Try block.
+ Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
+ Updated contrib/visupng/cexcept.h to version 1.0.0.
+ Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
+
+Version 1.0.7rc2 [June 28, 2000]
+ Updated license to include disclaimers required by UCITA.
+ Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
+
+Version 1.0.7 [July 1, 2000]
+ Revised the definition of "trans_values" in libpng.3/libpng.txt
+
+Version 1.0.8beta1 [July 8, 2000]
+ Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
+ Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
+ pngwutil.c.
+ Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
+ Removed unused "#include <assert.h>" from png.c
+ Added WindowsCE support.
+ Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
+
+Version 1.0.8beta2 [July 10, 2000]
+ Added project files to the wince directory and made further revisions
+ of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
+
+Version 1.0.8beta3 [July 11, 2000]
+ Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
+ for indexed-color input files to avoid potential double-freeing trans array
+ under some unusual conditions; problem was introduced in version 1.0.6f.
+ Further revisions to pngtest.c and files in the wince subdirectory.
+
+Version 1.0.8beta4 [July 14, 2000]
+ Added the files pngbar.png and pngbar.jpg to the distribution.
+ Added makefile.cygwin, and cygwin support in pngconf.h
+ Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
+
+Version 1.0.8rc1 [July 16, 2000]
+ Revised png_debug() macros and statements to eliminate compiler warnings.
+
+Version 1.0.8 [July 24, 2000]
+ Added png_flush() in pngwrite.c, after png_write_IEND().
+ Updated makefile.hpux to build a shared library.
+
+Version 1.0.9beta1 [November 10, 2000]
+ Fixed typo in scripts/makefile.hpux
+ Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
+ Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
+ Changed "cdrom.com" in documentation to "libpng.org"
+ Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
+ Changed type of "params" from voidp to png_voidp in png_read|write_png().
+ Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
+ Revised the 3 instances of WRITEFILE in pngtest.c.
+ Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
+ Updated png.rc in dll/msvc project
+ Revised makefile.dec to define and use LIBPATH and INCPATH
+ Increased size of global png_libpng_ver[] array from 12 to 18 chars.
+ Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
+ Removed duplicate png_crc_finish() from png_handle_bKGD() function.
+ Added a warning when application calls png_read_update_info() multiple times.
+ Revised makefile.cygwin
+ Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
+ Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
+
+Version 1.0.9beta2 [November 19, 2000]
+ Renamed the "dll" subdirectory "projects".
+ Added borland project files to "projects" subdirectory.
+ Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
+ Add error message in png_set_compression_buffer_size() when malloc fails.
+
+Version 1.0.9beta3 [November 23, 2000]
+ Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
+ Removed the png_flush() in pngwrite.c that crashes some applications
+ that don't set png_output_flush_fn.
+ Added makefile.macosx and makefile.aix to scripts directory.
+
+Version 1.0.9beta4 [December 1, 2000]
+ Change png_chunk_warning to png_warning in png_check_keyword().
+ Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
+
+Version 1.0.9beta5 [December 15, 2000]
+ Added support for filter method 64 (for PNG datastreams embedded in MNG).
+
+Version 1.0.9beta6 [December 18, 2000]
+ Revised png_set_filter() to accept filter method 64 when appropriate.
+ Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
+ help prevent applications from using MNG features in PNG datastreams.
+ Added png_permit_mng_features() function.
+ Revised libpng.3/libpng.txt. Changed "filter type" to "filter method".
+
+Version 1.0.9rc1 [December 23, 2000]
+ Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
+ Fixed error handling of unknown compression type in png_decompress_chunk().
+ In pngconf.h, define __cdecl when _MSC_VER is defined.
+
+Version 1.0.9beta7 [December 28, 2000]
+ Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
+ Revised memory management in png_set_hIST and png_handle_hIST in a backward
+ compatible manner. PLTE and tRNS were revised similarly.
+ Revised the iCCP chunk reader to ignore trailing garbage.
+
+Version 1.0.9beta8 [January 12, 2001]
+ Moved pngasmrd.h into pngconf.h.
+ Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
+
+Version 1.0.9beta9 [January 15, 2001]
+ Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
+ wince and msvc project module definition files.
+ Minor revision of makefile.cygwin.
+ Fixed bug with progressive reading of narrow interlaced images in pngpread.c
+
+Version 1.0.9beta10 [January 16, 2001]
+ Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
+ Fixed "png_mmx_supported" typo in project definition files.
+
+Version 1.0.9beta11 [January 19, 2001]
+ Updated makefile.sgi to make shared library.
+ Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
+ by default, for the benefit of DLL forward compatibility. These will
+ be re-enabled in version 1.2.0.
+
+Version 1.0.9rc2 [January 22, 2001]
+ Revised cygwin support.
+
+Version 1.0.9 [January 31, 2001]
+ Added check of cygwin's ALL_STATIC in pngconf.h
+ Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
+
+Version 1.0.10beta1 [March 14, 2001]
+ Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
+ Reformatted libpng.3 to eliminate bad line breaks.
+ Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
+ Added prototype for png_mmx_support() near the top of pnggccrd.c
+ Moved some error checking from png_handle_IHDR to png_set_IHDR.
+ Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
+ Revised png_mmx_support() function in pnggccrd.c
+ Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
+ Fixed memory leak in contrib/visupng/PngFile.c
+ Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
+ Added warnings when retrieving or setting gamma=0.
+ Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
+
+Version 1.0.10rc1 [March 23, 2001]
+ Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
+ and png_strlen.
+ Revised png_mmx_supported() function in pnggccrd.c to return proper value.
+ Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
+
+Version 1.0.10 [March 30, 2001]
+ Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
+ Added beos project files (Chris Herborth)
+
+Version 1.0.11beta1 [April 3, 2001]
+ Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
+ Removed a no-longer needed AIX work-around from pngconf.h
+ Changed several "//" single-line comments to C-style in pnggccrd.c
+
+Version 1.0.11beta2 [April 11, 2001]
+ Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
+ Updated scripts/pngos2.def
+
+Version 1.0.11beta3 [April 14, 2001]
+ Added checking the results of many instances of png_malloc() for NULL
+
+Version 1.0.11beta4 [April 20, 2001]
+ Undid the changes from version 1.0.11beta3. Added a check for NULL return
+ from user's malloc_fn().
+ Removed some useless type casts of the NULL pointer.
+ Added makefile.netbsd
+
+Version 1.0.11 [April 27, 2001]
+ Revised makefile.netbsd
+
+Version 1.0.12beta1 [May 14, 2001]
+ Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
+ Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
+ Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
+ Eliminated the png_error about apps using png_read|write_init(). Instead,
+ libpng will reallocate the png_struct and info_struct if they are too small.
+ This retains future binary compatibility for old applications written for
+ libpng-0.88 and earlier.
+
+Version 1.2.0beta1 [May 6, 2001]
+ Bumped DLLNUM to 2.
+ Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
+ by default.
+ Added runtime selection of MMX features.
+ Added png_set_strip_error_numbers function and related macros.
+
+Version 1.2.0beta2 [May 7, 2001]
+ Finished merging 1.2.0beta1 with version 1.0.11
+ Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
+
+Version 1.2.0beta3 [May 17, 2001]
+ Enabled user memory function by default.
+ Modified png_create_struct so it passes user mem_ptr to user memory allocator.
+ Increased png_mng_features flag from png_byte to png_uint_32.
+ Bumped shared-library (so-number) and dll-number to 3.
+
+Version 1.2.0beta4 [June 23, 2001]
+ Check for missing profile length field in iCCP chunk and free chunk_data
+ in case of truncated iCCP chunk.
+ Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
+ Bumped dll-number from 2 to 3 in makefile.cygwin
+ Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
+ if user attempts to run it on an 8-bit display.
+ Updated contrib/gregbook
+ Use png_malloc instead of png_zalloc to allocate palette in pngset.c
+ Updated makefile.ibmc
+ Added some typecasts to eliminate gcc 3.0 warnings. Changed prototypes
+ of png_write_oFFS width and height from png_uint_32 to png_int_32.
+ Updated example.c
+ Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
+
+Version 1.2.0beta5 [August 8, 2001]
+ Revised contrib/gregbook
+ Revised makefile.gcmmx
+ Revised pnggccrd.c to conditionally compile some thread-unsafe code only
+ when PNG_THREAD_UNSAFE_OK is defined.
+ Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
+ value exceeding 2^bit_depth-1
+ Revised makefile.sgi and makefile.sggcc
+ Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
+ Removed restriction that do_invert_mono only operate on 1-bit opaque files
+
+Version 1.2.0 [September 1, 2001]
+ Changed a png_warning() to png_debug() in pnggccrd.c
+ Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
+
+Version 1.2.1beta1 [October 19, 2001]
+ Revised makefile.std in contrib/pngminus
+ Include background_1 in png_struct regardless of gamma support.
+ Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
+ Revised example.c to provide more details about using row_callback().
+
+Version 1.2.1beta2 [October 25, 2001]
+ Added type cast to each NULL appearing in a function call, except for
+ WINCE functions.
+ Added makefile.so9.
+
+Version 1.2.1beta3 [October 27, 2001]
+ Removed type casts from all NULLs.
+ Simplified png_create_struct_2().
+
+Version 1.2.1beta4 [November 7, 2001]
+ Revised png_create_info_struct() and png_creat_struct_2().
+ Added error message if png_write_info() was omitted.
+ Type cast NULLs appearing in function calls when _NO_PROTO or
+ PNG_TYPECAST_NULL is defined.
+
+Version 1.2.1rc1 [November 24, 2001]
+ Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
+ is defined.
+ Changed typecast of "size" argument to png_size_t in pngmem.c calls to
+ the user malloc_fn, to agree with the prototype in png.h
+ Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
+ Updated makefile.sgi to recognize LIBPATH and INCPATH.
+ Updated various makefiles so "make clean" does not remove previous major
+ version of the shared library.
+
+Version 1.2.1rc2 [December 4, 2001]
+ Always allocate 256-entry internal palette, hist, and trans arrays, to
+ avoid out-of-bounds memory reference caused by invalid PNG datastreams.
+ Added a check for prefix_length > data_length in iCCP chunk handler.
+
+Version 1.2.1 [December 7, 2001]
+ None.
+
+Version 1.2.2beta1 [February 22, 2002]
+ Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
+ Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
+ libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
+ Revised makefile.darwin to remove "-undefined suppress" option.
+ Added checks for gamma and chromaticity values over 21474.83, which exceed
+ the limit for PNG unsigned 32-bit integers when encoded.
+ Revised calls to png_create_read_struct() and png_create_write_struct()
+ for simpler debugging.
+ Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
+
+Version 1.2.2beta2 [February 23, 2002]
+ Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
+ Check for invalid image dimensions in png_get_IHDR.
+ Added missing "fi;" in the install target of the SGI makefiles.
+ Added install-static to all makefiles that make shared libraries.
+ Always do gamma compensation when image is partially transparent.
+
+Version 1.2.2beta3 [March 7, 2002]
+ Compute background.gray and background_1.gray even when color_type is RGB
+ in case image gets reduced to gray later.
+ Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
+ Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
+ Removed unused png_write_destroy_info prototype from png.h
+ Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
+ Added install-shared target to all makefiles that make shared libraries.
+ Stopped a double free of palette, hist, and trans when not using free_me.
+ Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
+
+Version 1.2.2beta4 [March 8, 2002]
+ Compute background.gray and background_1.gray even when color_type is RGB
+ in case image gets reduced to gray later (Jason Summers).
+ Relocated a misplaced /bin/rm in the "install-shared" makefile targets
+ Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
+
+Version 1.2.2beta5 [March 26, 2002]
+ Added missing PNGAPI to several function definitions.
+ Check for invalid bit_depth or color_type in png_get_IHDR(), and
+ check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
+ Revised iTXt support to accept NULL for lang and lang_key.
+ Compute gamma for color components of background even when color_type is gray.
+ Changed "()" to "{}" in scripts/libpng.pc.in.
+ Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
+ Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
+
+Version 1.2.2beta6 [March 31, 2002]
+
+Version 1.0.13beta1 [March 31, 2002]
+ Prevent png_zalloc() from trying to memset memory that it failed to acquire.
+ Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
+ Ensure that the right function (user or default) is used to free the
+ png_struct after an error in png_create_read_struct_2().
+
+Version 1.2.2rc1 [April 7, 2002]
+
+Version 1.0.13rc1 [April 7, 2002]
+ Save the ebx register in pnggccrd.c (Sami Farin)
+ Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
+ Updated makefiles to put headers in include/libpng and remove old include/*.h.
+
+Version 1.2.2 [April 15, 2002]
+
+Version 1.0.13 [April 15, 2002]
+ Revised description of png_set_filter() in libpng.3/libpng.txt.
+ Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
+
+Version 1.0.13patch01 [April 17, 2002]
+
+Version 1.2.2patch01 [April 17, 2002]
+ Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and
+ makefile.sggcc
+ Fixed VER -> PNGVER typo in makefile.macosx and added install-static to
+ install
+ Added install: target to makefile.32sunu and makefile.64sunu
+
+Version 1.0.13patch03 [April 18, 2002]
+
+Version 1.2.2patch03 [April 18, 2002]
+ Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
+ subdirectory to libpngNN subdirectory without the full pathname.
+ Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
+
+Version 1.2.3rc1 [April 28, 2002]
+ Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
+ Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
+ Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
+ Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
+ Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
+ Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
+ Revised makefile.darwin to make relative links without full pathname.
+ Added setjmp() at the end of png_create_*_struct_2() in case user forgets
+ to put one in their application.
+ Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
+ removed them from module definition files.
+
+Version 1.2.3rc2 [May 1, 2002]
+ Fixed bug in reporting number of channels in pngget.c and pngset.c,
+ that was introduced in version 1.2.2beta5.
+ Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
+ png_default_flush(), and png_push_fill_buffer() and included them in
+ module definition files.
+ Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
+
+Version 1.2.3rc3 [May 1, 2002]
+ Revised prototype for png_default_flush()
+ Remove old libpng.pc and libpngNN.pc before installing new ones.
+
+Version 1.2.3rc4 [May 2, 2002]
+ Typos in *.def files (png_default_read|write -> png_default_read|write_data)
+ In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
+ Added libpng-config and libpngNN-config and modified makefiles to install
+ them.
+ Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
+ Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
+
+Version 1.2.3rc5 [May 11, 2002]
+ Changed "error" and "message" in prototypes to "error_message" and
+ "warning_message" to avoid namespace conflict.
+ Revised 15 makefiles to build libpng-config from libpng-config-*.in
+ Once more restored png_zalloc and png_zfree to regular nonexported form.
+ Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
+ to nonexported form, but with PNGAPI, and removed them from module def
+ files.
+
+Version 1.2.3rc6 [May 14, 2002]
+ Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
+ Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
+ Removed leftover libpng-config "sed" script from four makefiles.
+ Revised libpng-config creating script in 16 makefiles.
+
+Version 1.2.3 [May 22, 2002]
+ Revised libpng-config target in makefile.cygwin.
+ Removed description of png_set_mem_fn() from documentation.
+ Revised makefile.freebsd.
+ Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
+ Revised projects/msvc/README.txt
+ Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
+
+Version 1.2.4beta1 [May 24, 2002]
+ Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
+ Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
+ Added missing "\" before closing double quote in makefile.gcmmx.
+ Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
+ functions.
+
+Version 1.2.4beta2 [June 25, 2002]
+ Plugged memory leak of png_ptr->current_text (Matt Holgate).
+ Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
+ Added -soname to the loader flags in makefile.dec, makefile.sgi, and
+ makefile.sggcc.
+ Added "test-installed" target to makefile.linux, makefile.gcmmx,
+ makefile.sgi, and makefile.sggcc.
+
+Version 1.2.4beta3 [June 28, 2002]
+ Plugged memory leak of row_buf in pngtest.c when there is a png_error().
+ Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
+ Added "test-installed" target to makefile.32sunu, makefile.64sunu,
+ makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
+ makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
+
+Version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
+ Added "test-installed" target to makefile.cygwin and makefile.sco.
+ Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
+
+Version 1.2.4 and 1.0.14 [July 8, 2002]
+ Changed png_warning() to png_error() when width is too large to process.
+
+Version 1.2.4patch01 [July 20, 2002]
+ Revised makefile.cygwin to use DLL number 12 instead of 13.
+
+Version 1.2.5beta1 [August 6, 2002]
+ Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
+ Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
+ Removed some stray *.o files from contrib/gregbook.
+ Changed png_error() to png_warning() about "Too much data" in pngpread.c
+ and about "Extra compressed data" in pngrutil.c.
+ Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
+ Updated makefile.hpgcc
+ Updated png.c and pnggccrd.c handling of return from png_mmx_support()
+
+Version 1.2.5beta2 [August 15, 2002]
+ Only issue png_warning() about "Too much data" in pngpread.c when avail_in
+ is nonzero.
+ Updated makefiles to install a separate libpng.so.3 with its own rpath.
+
+Version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
+ Revised makefiles to not remove previous minor versions of shared libraries.
+
+Version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
+ Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
+ library loader directive.
+ Added missing "$OBJSDLL" line to makefile.gcmmx.
+ Added missing "; fi" to makefile.32sunu.
+
+Version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
+ Revised libpng-config script.
+
+Version 1.2.5 and 1.0.15 [October 3, 2002]
+ Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
+ and makefile.aix.
+ Relocated two misplaced PNGAPI lines in pngtest.c
+
+Version 1.2.6beta1 [October 22, 2002]
+ Commented out warning about uninitialized mmx_support in pnggccrd.c.
+ Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
+ Relocated two more misplaced PNGAPI lines in pngtest.c
+ Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
+ introduced in version 1.0.2.
+ Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
+
+Version 1.2.6beta2 [November 1, 2002]
+ Added libpng-config "--ldopts" output.
+ Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
+ in makefiles.
+
+Version 1.2.6beta3 [July 18, 2004]
+ Reverted makefile changes from version 1.2.6beta2 and some of the changes
+ from version 1.2.6beta1; these will be postponed until version 1.2.7.
+ Version 1.2.6 is going to be a simple bugfix release.
+ Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
+ Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
+ Added "#!/bin/sh" at the top of configure, for recognition of the
+ 'x' flag under Cygwin (Cosmin).
+ Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
+ Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
+ Fixed the special memory handler for Borland C under DOS, in pngmem.c
+ (Cosmin).
+ Removed some spurious assignments in pngrutil.c (Cosmin).
+ Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
+ on 16-bit platforms (Cosmin).
+ Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
+ Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
+ in png_handle_sRGB() (Cosmin).
+ Added compression_type to png_struct, and optimized the window size
+ inside the deflate stream (Cosmin).
+ Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
+ Fixed handling of unknown chunks that come after IDAT (Cosmin).
+ Allowed png_error() and png_warning() to work even if png_ptr == NULL
+ (Cosmin).
+ Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
+ (Cosmin).
+ Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
+ Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
+ values in png.c (Simon-Pierre, Cosmin).
+ Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
+ Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
+ (Simon-Pierre).
+ Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
+ of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
+ Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
+ Updated scripts/makefile.vc(a)win32 (Cosmin).
+ Updated the MSVC project (Simon-Pierre, Cosmin).
+ Updated the Borland C++ Builder project (Cosmin).
+ Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
+ Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
+ Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
+ Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
+ (Cosmin).
+ Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
+ projects/cbuilder5/ (Cosmin).
+ Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
+ and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
+ Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
+ Changed line endings to DOS style in cbuilder5 and visualc6 files, even
+ in the tar.* distributions (Cosmin).
+ Updated contrib/visupng/VisualPng.dsp (Cosmin).
+ Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
+ Added a separate distribution with "configure" and supporting files (Junichi).
+
+Version 1.2.6beta4 [July 28, 2004]
+ Added user ability to change png_size_t via a PNG_SIZE_T macro.
+ Added png_sizeof() and png_convert_size() functions.
+ Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
+ Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
+ which would indicate an overflow.
+ Changed sPLT failure action from png_error to png_warning and abandon chunk.
+ Changed sCAL and iCCP failures from png_error to png_warning and abandon.
+ Added png_get_uint_31(png_ptr, buf) function.
+ Added PNG_UINT_32_MAX macro.
+ Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
+ Made png_zalloc() issue a png_warning and return NULL on potential
+ overflow.
+ Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
+ Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
+ Revised Borland portion of png_malloc() to return NULL or issue
+ png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
+ Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
+ sequential read support.
+ Added some "#if PNG_WRITE_SUPPORTED" blocks.
+ Added #ifdef to remove some redundancy in png_malloc_default().
+ Use png_malloc instead of png_zalloc to allocate the pallete.
+
+Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
+ Fixed buffer overflow vulnerability in png_handle_tRNS()
+ Fixed integer arithmetic overflow vulnerability in png_read_png().
+ Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
+ duplicate chunk types to go undetected.
+ Fixed some timestamps in the -config version
+ Rearranged order of processing of color types in png_handle_tRNS().
+ Added ROWBYTES macro to calculate rowbytes without integer overflow.
+ Updated makefile.darwin and removed makefile.macosx from scripts directory.
+ Imposed default one million column, one-million row limits on the image
+ dimensions, and added png_set_user_limits() function to override them.
+ Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
+ Fixed wrong cast of returns from png_get_user_width|height_max().
+ Changed some "keep the compiler happy" from empty statements to returns,
+ Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
+
+Version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
+ Revised makefile.darwin and makefile.solaris. Removed makefile.macosx.
+ Revised pngtest's png_debug_malloc() to use png_malloc() instead of
+ png_malloc_default() which is not supposed to be exported.
+ Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
+ pngpread.c. Bug was introduced in 1.2.6rc1.
+ Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
+ Fixed old bug in RGB to Gray transformation.
+ Fixed problem with 64-bit compilers by casting arguments to abs()
+ to png_int_32.
+ Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
+ Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
+ Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
+ Added code to update the row_info->colortype in png_do_read_filler() (MSB).
+
+Version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
+ Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
+ trouble with some 64-bit compilers. Created PNG_OUT_OF_RANGE() macro.
+ Revised documentation of png_set_keep_unknown_chunks().
+ Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
+ Moved "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
+ Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
+
+Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
+ Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
+ "pinfo" was out of place).
+
+Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
+ Moved "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
+ section of png.h where they were inadvertently placed in version rc3.
+
+Version 1.2.6 and 1.0.16 [August 15, 2004]
+ Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
+
+Version 1.2.7beta1 [August 26, 2004]
+ Removed unused pngasmrd.h file.
+ Removed references to uu.net for archived files. Added references to
+ PNG Spec (second edition) and the PNG ISO/IEC Standard.
+ Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
+ Fixed bug with "optimized window size" in the IDAT datastream, that
+ causes libpng to write PNG files with incorrect zlib header bytes.
+
+Version 1.2.7beta2 [August 28, 2004]
+ Fixed bug with sCAL chunk and big-endian machines (David Munro).
+ Undid new code added in 1.2.6rc2 to update the color_type in
+ png_set_filler().
+ Added png_set_add_alpha() that updates color type.
+
+Version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
+ Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
+
+Version 1.2.7 and 1.0.17 [September 12, 2004]
+ Added makefile.hp64
+ Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
+
+Version 1.2.8beta1 [November 1, 2004]
+ Fixed bug in png_text_compress() that would fail to complete a large block.
+ Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
+ strip alpha operation in png_do_strip_filler().
+ Added PNG_1_2_X definition in pngconf.h
+ Use #ifdef to comment out png_info_init in png.c and png_read_init in
+ pngread.c (as of 1.3.0)
+
+Version 1.2.8beta2 [November 2, 2004]
+ Reduce color_type to a nonalpha type after strip alpha operation in
+ png_do_strip_filler().
+
+Version 1.2.8beta3 [November 3, 2004]
+ Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
+
+Version 1.2.8beta4 [November 12, 2004]
+ Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
+ Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
+ Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
+ of data type in deflate (Cosmin).
+ Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
+ PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8beta5 [November 20, 2004]
+ Use png_ptr->flags instead of png_ptr->transformations to pass
+ PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
+ compatibility.
+ Revised handling of SPECIALBUILD, PRIVATEBUILD,
+ PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8rc1 [November 24, 2004]
+ Moved handling of BUILD macros from pngconf.h to png.h
+ Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
+ omitted from beta5.
+ Revised scripts/pngw32.rc
+ Despammed mailing addresses by masking "@" with "at".
+ Inadvertently installed a supposedly faster test version of pngrutil.c
+
+Version 1.2.8rc2 [November 26, 2004]
+ Added two missing "\" in png.h
+ Change tests in pngread.c and pngpread.c to
+ if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
+ png_do_read_transformations(png_ptr);
+
+Version 1.2.8rc3 [November 28, 2004]
+ Reverted pngrutil.c to version libpng-1.2.8beta5.
+ Added scripts/makefile.elf with supporting code in pngconf.h for symbol
+ versioning (John Bowler).
+
+Version 1.2.8rc4 [November 29, 2004]
+ Added projects/visualc7 (Simon-pierre).
+
+Version 1.2.8rc5 [November 29, 2004]
+ Fixed new typo in scripts/pngw32.rc
+
+Version 1.2.8 [December 3, 2004]
+ Removed projects/visualc7, added projects/visualc71.
+
+Version 1.2.9beta1 [February 21, 2006]
+ Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints
+ Revised man page and libpng.txt to make it clear that one should not call
+ png_read_end or png_write_end after png_read_png or png_write_png.
+ Updated references to png-mng-implement mailing list.
+ Fixed an incorrect typecast in pngrutil.c
+ Added PNG_NO_READ_SUPPORTED conditional for making a write-only library.
+ Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional.
+ Optimized alpha-inversion loops in pngwtran.c
+ Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c
+ Make sure num_trans is <= 256 before copying data in png_set_tRNS().
+ Make sure num_palette is <= 256 before copying data in png_set_PLTE().
+ Interchanged order of write_swap_alpha and write_invert_alpha transforms.
+ Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin).
+ Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin).
+ Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin).
+ Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16,
+ png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin).
+ Added type cast (png_byte) in png_write_sCAL() (Cosmin).
+ Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin).
+ Default iTXt support was inadvertently enabled.
+
+Version 1.2.9beta2 [February 21, 2006]
+ Check for png_rgb_to_gray and png_gray_to_rgb read transformations before
+ checking for png_read_dither in pngrtran.c
+ Revised checking of chromaticity limits to accommodate extended RGB
+ colorspace (John Denker).
+ Changed line endings in some of the project files to CRLF, even in the
+ "Unix" tar distributions (Cosmin).
+ Made png_get_int_32 and png_save_int_32 always available (Cosmin).
+ Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def
+ with the newly exported functions.
+ Eliminated distributions without the "configure" script.
+ Updated INSTALL instructions.
+
+Version 1.2.9beta3 [February 24, 2006]
+ Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp
+ Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler)
+ Removed reference to pngasmrd.h from Makefile.am
+ Renamed CHANGES to ChangeLog.
+ Renamed LICENSE to COPYING.
+ Renamed ANNOUNCE to NEWS.
+ Created AUTHORS file.
+
+Version 1.2.9beta4 [March 3, 2006]
+ Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac
+ Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING.
+ Removed newline from the end of some error and warning messages.
+ Removed test for sqrt() from configure.ac and configure.
+ Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix).
+ Disabled default iTXt support that was inadvertently enabled in
+ libpng-1.2.9beta1.
+ Added "OS2" to list of systems that don't need underscores, in pnggccrd.c
+ Removed libpng version and date from *.c files.
+
+Version 1.2.9beta5 [March 4, 2006]
+ Removed trailing blanks from source files.
+ Put version and date of latest change in each source file, and changed
+ copyright year accordingly.
+ More cleanup of configure.ac, Makefile.am, and associated scripts.
+ Restored scripts/makefile.elf which was inadvertently deleted.
+
+Version 1.2.9beta6 [March 6, 2006]
+ Fixed typo (RELEASE) in configuration files.
+
+Version 1.2.9beta7 [March 7, 2006]
+ Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am
+ Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s()
+ in png.h.
+ Updated makefile.elf as suggested by debian.
+ Made cosmetic changes to some makefiles, adding LN_SF and other macros.
+ Made some makefiles accept "exec_prefix".
+
+Version 1.2.9beta8 [March 9, 2006]
+ Fixed some "#if defined (..." which should be "#if defined(..."
+ Bug introduced in libpng-1.2.8.
+ Fixed inconsistency in definition of png_default_read_data()
+ Restored blank that was lost from makefile.sggcc "clean" target in beta7.
+ Revised calculation of "current" and "major" for irix in ltmain.sh
+ Changed "mkdir" to "MKDIR_P" in some makefiles.
+ Separated PNG_EXPAND and PNG_EXPAND_tRNS.
+ Added png_set_expand_gray_1_2_4_to_8() and deprecated
+ png_set_gray_1_2_4_to_8() which also expands tRNS to alpha.
+
+Version 1.2.9beta9 [March 10, 2006]
+ Include "config.h" in pngconf.h when available.
+ Added some checks for NULL png_ptr or NULL info_ptr (timeless)
+
+Version 1.2.9beta10 [March 20, 2006]
+ Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin)
+ Made pnggccrd.c PIC-compliant (Christian Aichinger).
+ Added makefile.mingw (Wolfgang Glas).
+ Revised pngconf.h MMX checking.
+
+Version 1.2.9beta11 [March 22, 2006]
+ Fixed out-of-order declaration in pngwrite.c that was introduced in beta9
+ Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros.
+
+Version 1.2.9rc1 [March 31, 2006]
+ Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin).
+ Removed nonsensical assertion check from pngtest.c (Cosmin).
+
+Version 1.2.9 [April 14, 2006]
+ Revised makefile.beos and added "none" selector in ltmain.sh
+
+Version 1.2.10beta1 [April 15, 2006]
+ Renamed "config.h" to "png_conf.h" and revised Makefile.am to add
+ -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h
+ to include png_conf.h only when PNG_BUILDING_LIBPNG is defined.
+
+Version 1.2.10beta2 [April 15, 2006]
+ Manually updated Makefile.in and configure. Changed png_conf.h.in
+ back to config.h.
+
+Version 1.2.10beta3 [April 15, 2006]
+ Change png_conf.h back to config.h in pngconf.h.
+
+Version 1.2.10beta4 [April 16, 2006]
+ Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*.
+
+Version 1.2.10beta5 [April 16, 2006]
+ Added a configure check for compiling assembler code in pnggccrd.c
+
+Version 1.2.10beta6 [April 17, 2006]
+ Revised the configure check for pnggccrd.c
+ Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@
+ Added @LIBPNG_DEFINES@ to arguments when building libpng.sym
+
+Version 1.2.10beta7 [April 18, 2006]
+ Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles.
+
+Version 1.2.10rc1 [April 19, 2006]
+ Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD
+ Fixed "LN_FS" typo in makefile.sco and makefile.solaris.
+
+Version 1.2.10rc2 [April 20, 2006]
+ Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE
+ in configure.ac and configure
+ Made the configure warning about versioned symbols less arrogant.
+
+Version 1.2.10rc3 [April 21, 2006]
+ Added a note in libpng.txt that png_set_sig_bytes(8) can be used when
+ writing an embedded PNG without the 8-byte signature.
+ Revised makefiles and configure to avoid making links to libpng.so.*
+
+Version 1.2.10 [April 23, 2006]
+ Reverted configure to "rc2" state.
+
+Version 1.2.11beta1 [May 31, 2006]
+ scripts/libpng.pc.in contained "configure" style version info and would
+ not work with makefiles.
+ The shared-library makefiles were linking to libpng.so.0 instead of
+ libpng.so.3 compatibility as the library.
+
+Version 1.2.11beta2 [June 2, 2006]
+ Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+ buffer overflow.
+ Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb)
+
+Version 1.2.11beta3 [June 5, 2006]
+ Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin).
+ Removed the accidental leftover Makefile.in~ (Cosmin).
+ Avoided potential buffer overflow and optimized buffer in
+ png_write_sCAL(), png_write_sCAL_s() (Cosmin).
+ Removed the include directories and libraries from CFLAGS and LDFLAGS
+ in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin).
+
+Version 1.2.11beta4 [June 6, 2006]
+ Allow zero-length IDAT chunks after the entire zlib datastream, but not
+ after another intervening chunk type.
+
+Version 1.0.19rc1, 1.2.11rc1 [June 13, 2006]
+ Deleted extraneous square brackets from [config.h] in configure.ac
+
+Version 1.0.19rc2, 1.2.11rc2 [June 14, 2006]
+ Added prototypes for PNG_INCH_CONVERSIONS functions to png.h
+ Revised INSTALL and autogen.sh
+ Fixed typo in several makefiles (-W1 should be -Wl)
+ Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+
+Version 1.0.19rc3, 1.2.11rc3 [June 15, 2006]
+ Removed the new typedefs for 64-bit systems (delay until version 1.4.0)
+ Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid
+ reading out of bounds.
+
+Version 1.0.19rc4, 1.2.11rc4 [June 15, 2006]
+ Really removed the new typedefs for 64-bit systems.
+
+Version 1.0.19rc5, 1.2.11rc5 [June 22, 2006]
+ Removed png_sig_bytes entry from scripts/pngw32.def
+
+Version 1.0.19, 1.2.11 [June 26, 2006]
+ None.
+
+Version 1.0.20, 1.2.12 [June 27, 2006]
+ Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+ buffer overflow.
+
+Version 1.2.13beta1 [October 2, 2006]
+ Removed AC_FUNC_MALLOC from configure.ac
+ Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+ Change "logical" to "bitwise" throughout documentation.
+ Detect and fix attempt to write wrong iCCP profile length.
+
+Version 1.0.21, 1.2.13 [November 14, 2006]
+ Fix potential buffer overflow in sPLT chunk handler.
+ Fix Makefile.am to not try to link to noexistent files.
+ Check all exported functions for NULL png_ptr.
+
+Version 1.2.14beta1 [November 17, 2006]
+ Relocated three misplaced tests for NULL png_ptr.
+ Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+ Build configure with autoconf-2.60 instead of 2.59
+
+Version 1.2.14beta2 [November 17, 2006]
+ Added some typecasts in png_zalloc().
+
+Version 1.2.14rc1 [November 20, 2006]
+ Changed "strtod" to "png_strtod" in pngrutil.c
+
+Version 1.0.22, 1.2.14 [November 27, 2006]
+ Added missing "$(srcdir)" in Makefile.am and Makefile.in
+
+Version 1.2.15beta1 [December 3, 2006]
+ Generated configure with autoconf-2.61 instead of 2.60
+ Revised configure.ac to update libpng.pc and libpng-config.
+
+Version 1.2.15beta2 [December 3, 2006]
+ Always export MMX asm functions, just stubs if not building pnggccrd.c
+
+Version 1.2.15beta3 [December 4, 2006]
+ Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.2.15beta4 [December 7, 2006]
+ Added scripts/CMakeLists.txt
+ Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta
+
+Version 1.2.15beta5 [December 7, 2006]
+ Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c
+ Revised scripts/CMakeLists.txt
+
+Version 1.2.15beta6 [December 13, 2006]
+ Revised scripts/CMakeLists.txt and configure.ac
+
+Version 1.2.15rc1 [December 18, 2006]
+ Revised scripts/CMakeLists.txt
+
+Version 1.2.15rc2 [December 21, 2006]
+ Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+ Added scripts/makefile.nommx
+
+Version 1.2.15rc3 [December 25, 2006]
+ Fixed shared library numbering error that was introduced in 1.2.15beta6.
+
+Version 1.2.15rc4 [December 27, 2006]
+ Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
+
+Version 1.2.15rc5 [December 31, 2006]
+ Revised handling of rgb_to_gray.
+
+Version 1.2.15 [January 5, 2007]
+ Added some (unsigned long) typecasts in pngtest.c to avoid printing errors.
+
+Version 1.2.16beta1 [January 6, 2007]
+ Fix bugs in makefile.nommx
+
+Version 1.2.16beta2 [January 16, 2007]
+ Revised scripts/CMakeLists.txt
+
+Version 1.2.16 [January 31, 2007]
+ No changes.
+
+Version 1.2.17beta1 [March 6, 2007]
+ Revised scripts/CMakeLists.txt to install both shared and static libraries.
+ Deleted a redundant line from pngset.c.
+
+Version 1.2.17beta2 [April 26, 2007]
+ Relocated misplaced test for png_ptr == NULL in pngpread.c
+ Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN
+ flags.
+ Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_*
+ Added pngerror() when write_IHDR fails in deflateInit2().
+ Added "const" to some array declarations.
+ Mention examples of libpng usage in the libpng*.txt and libpng.3 documents.
+
+Version 1.2.17rc1 [May 4, 2007]
+ No changes.
+
+Version 1.2.17rc2 [May 8, 2007]
+ Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications
+ calling set_unknown_chunk_location() need them.
+ Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in
+ png_set_expand_gray_1_2_4_to_8().
+ Added png_ptr->unknown_chunk to hold working unknown chunk data, so it
+ can be free'ed in case of error. Revised unknown chunk handling in
+ pngrutil.c and pngpread.c to use this structure.
+
+Version 1.2.17rc3 [May 8, 2007]
+ Revised symbol-handling in configure script.
+
+Version 1.2.17rc4 [May 10, 2007]
+ Revised unknown chunk handling to avoid storing unknown critical chunks.
+
+Version 1.0.25 [May 15, 2007]
+Version 1.2.17 [May 15, 2007]
+ Added "png_ptr->num_trans=0" before error return in png_handle_tRNS,
+ to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664)
+
+Version 1.0.26 [May 15, 2007]
+Version 1.2.18 [May 15, 2007]
+ Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script
+
+Version 1.2.19beta1 [May 18, 2007]
+ Changed "const static" to "static PNG_CONST" everywhere, mostly undoing
+ change of libpng-1.2.17beta2. Changed other "const" to "PNG_CONST"
+ Changed some handling of unused parameters, to avoid compiler warnings.
+ "if (unused == NULL) return;" becomes "unused = unused".
+
+Version 1.2.19beta2 [May 18, 2007]
+ Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)
+
+Version 1.2.19beta3 [May 19, 2007]
+ Add some "png_byte" typecasts in png_check_keyword() and write new_key
+ instead of key in zTXt chunk (Kevin Ryde).
+
+Version 1.2.19beta4 [May 21, 2007]
+ Add png_snprintf() function and use it in place of sprint() for improved
+ defense against buffer overflows.
+
+Version 1.2.19beta5 [May 21, 2007]
+ Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
+ Changed handling of more unused parameters, to avoid compiler warnings.
+ Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.
+
+Version 1.2.19beta6 [May 22, 2007]
+ Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
+ Added a special "_MSC_VER" case that defines png_snprintf to _snprintf
+
+Version 1.2.19beta7 [May 22, 2007]
+ Squelched png_squelch_warnings() in pnggccrd.c and added
+ an #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused
+ the warnings that png_squelch_warnings was squelching.
+
+Version 1.2.19beta8 [May 22, 2007]
+ Removed __MMX__ from test in pngconf.h.
+
+Version 1.2.19beta9 [May 23, 2007]
+ Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
+ Revised png_squelch_warnings() so it might work.
+ Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.
+
+Version 1.2.19beta10 [May 24, 2007]
+ Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.
+
+Version 1.4.0beta1 [April 20, 2006]
+ Enabled iTXt support (changes png_struct, thus requires so-number change).
+ Cleaned up PNG_ASSEMBLER_CODE_SUPPORTED vs PNG_MMX_CODE_SUPPORTED
+ Eliminated PNG_1_0_X and PNG_1_2_X macros.
+ Removed deprecated functions png_read_init, png_write_init, png_info_init,
+ png_permit_empty_plte, png_set_gray_1_2_4_to_8, png_check_sig, and
+ removed the deprecated macro PNG_MAX_UINT.
+ Moved "PNG_INTERNAL" parts of png.h and pngconf.h into pngintrn.h
+ Removed many WIN32_WCE #ifdefs (Cosmin).
+ Reduced dependency on C-runtime library when on Windows (Simon-Pierre)
+ Replaced sprintf() with png_sprintf() (Simon-Pierre)
+
+Version 1.4.0beta2 [April 20, 2006]
+ Revised makefiles and configure to avoid making links to libpng.so.*
+ Moved some leftover MMX-related defines from pngconf.h to pngintrn.h
+ Updated scripts/pngos2.def, pngw32.def, and projects/wince/png32ce.def
+
+Version 1.4.0beta3 [May 10, 2006]
+ Updated scripts/pngw32.def to comment out MMX functions.
+ Added PNG_NO_GET_INT_32 and PNG_NO_SAVE_INT_32 macros.
+ Scripts/libpng.pc.in contained "configure" style version info and would
+ not work with makefiles.
+ Revised pngconf.h and added pngconf.h.in, so makefiles and configure can
+ pass defines to libpng and applications.
+
+Version 1.4.0beta4 [May 11, 2006]
+ Revised configure.ac, Makefile.am, and many of the makefiles to write
+ their defines in pngconf.h.
+
+Version 1.4.0beta5 [May 15, 2006]
+ Added a missing semicolon in Makefile.am and Makefile.in
+ Deleted extraneous square brackets from configure.ac
+
+Version 1.4.0beta6 [June 2, 2006]
+ Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+ buffer overflow.
+ Changed sonum from 0 to 1.
+ Removed unused prototype for png_check_sig() from png.h
+
+Version 1.4.0beta7 [June 16, 2006]
+ Exported png_write_sig (Cosmin).
+ Optimized buffer in png_handle_cHRM() (Cosmin).
+ Set pHYs = 2835 x 2835 pixels per meter, and added
+ sCAL = 0.352778e-3 x 0.352778e-3 meters, in pngtest.png (Cosmin).
+ Added png_set_benign_errors(), png_benign_error(), png_chunk_benign_error().
+ Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+ Added "(unsigned long)" typecast on png_uint_32 variables in printf lists.
+
+Version 1.4.0beta8 [June 22, 2006]
+ Added demonstration of user chunk support in pngtest.c, to support the
+ public sTER chunk and a private vpAg chunk.
+
+Version 1.4.0beta9 [July 3, 2006]
+ Removed ordinals from scripts/pngw32.def and removed png_info_int and
+ png_set_gray_1_2_4_to_8 entries.
+ Inline call of png_get_uint_32() in png_get_uint_31().
+ Use png_get_uint_31() to get vpAg width and height in pngtest.c
+ Removed WINCE and Netware projects.
+ Removed standalone Y2KINFO file.
+
+Version 1.4.0beta10 [July 12, 2006]
+ Eliminated automatic copy of pngconf.h to pngconf.h.in from configure and
+ some makefiles, because it was not working reliably. Instead, distribute
+ pngconf.h.in along with pngconf.h and cause configure and some of the
+ makefiles to update pngconf.h from pngconf.h.in.
+ Added pngconf.h to DEPENDENCIES in Makefile.am
+
+Version 1.4.0beta11 [August 19, 2006]
+ Removed AC_FUNC_MALLOC from configure.ac.
+ Added a warning when writing iCCP profile with mismatched profile length.
+ Patched pnggccrd.c to assemble on x86_64 platforms.
+ Moved chunk header reading into a separate function png_read_chunk_header()
+ in pngrutil.c. The chunk header (len+sig) is now serialized in a single
+ operation (Cosmin).
+ Implemented support for I/O states. Added png_ptr member io_state, and
+ functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+ (Cosmin).
+ Added png_get_io_chunk_name and png_get_io_state to scripts/*.def (Cosmin).
+ Renamed scripts/pngw32.* to scripts/pngwin.* (Cosmin).
+ Removed the include directories and libraries from CFLAGS and LDFLAGS
+ in scripts/makefile.gcc (Cosmin).
+ Used png_save_uint_32() to set vpAg width and height in pngtest.c (Cosmin).
+ Cast to proper type when getting/setting vpAg units in pngtest.c (Cosmin).
+ Added pngintrn.h to the Visual C++ projects (Cosmin).
+ Removed scripts/list (Cosmin).
+ Updated copyright year in scripts/pngwin.def (Cosmin).
+ Removed PNG_TYPECAST_NULL and used standard NULL consistently (Cosmin).
+ Disallowed the user to redefine png_size_t, and enforced a consistent use
+ of png_size_t across libpng (Cosmin).
+ Changed the type of png_ptr->rowbytes, PNG_ROWBYTES() and friends
+ to png_size_t (Cosmin).
+ Removed png_convert_size() and replaced png_sizeof with sizeof (Cosmin).
+ Removed some unnecessary type casts (Cosmin).
+ Changed prototype of png_get_compression_buffer_size() and
+ png_set_compression_buffer_size() to work with png_size_t instead of
+ png_uint_32 (Cosmin).
+ Removed png_memcpy_check() and png_memset_check() (Cosmin).
+ Fixed a typo (png_byte --> png_bytep) in libpng.3 and libpng.txt (Cosmin).
+ Clarified that png_zalloc() does not clear the allocated memory,
+ and png_zalloc() and png_zfree() cannot be PNGAPI (Cosmin).
+ Renamed png_mem_size_t to png_alloc_size_t, fixed its definition in
+ pngconf.h, and used it in all memory allocation functions (Cosmin).
+ Renamed pngintrn.h to pngpriv.h, added a comment at the top of the file
+ mentioning that the symbols declared in that file are private, and
+ updated the scripts and the Visual C++ projects accordingly (Cosmin).
+ Removed circular references between pngconf.h and pngconf.h.in in
+ scripts/makefile.vc*win32 (Cosmin).
+ Removing trailing '.' from the warning and error messages (Cosmin).
+ Added pngdefs.h that is built by makefile or configure, instead of
+ pngconf.h.in (Glenn).
+ Detect and fix attempt to write wrong iCCP profile length.
+
+Version 1.4.0beta12 [October 19, 2006]
+ Changed "logical" to "bitwise" in the documentation.
+ Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+ Add a typecast to stifle compiler warning in pngrutil.c
+
+Version 1.4.0beta13 [November 10, 2006]
+ Fix potential buffer overflow in sPLT chunk handler.
+ Fix Makefile.am to not try to link to noexistent files.
+
+Version 1.4.0beta14 [November 15, 2006]
+ Check all exported functions for NULL png_ptr.
+
+Version 1.4.0beta15 [November 17, 2006]
+ Relocated two misplaced tests for NULL png_ptr.
+ Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+ Build configure with autoconf-2.60 instead of 2.59
+ Add "install: all" in Makefile.am so "configure; make install" will work.
+
+Version 1.4.0beta16 [November 17, 2006]
+ Added a typecast in png_zalloc().
+
+Version 1.4.0beta17 [December 4, 2006]
+ Changed "new_key[79] = '\0';" to "(*new_key)[79] = '\0';" in pngwutil.c
+ Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.4.0beta18 [December 7, 2006]
+ Added scripts/CMakeLists.txt
+
+Version 1.4.0beta19 [May 16, 2007]
+ Revised scripts/CMakeLists.txt
+ Rebuilt configure and Makefile.in with newer tools.
+ Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+ Added scripts/makefile.nommx
+
+Version 1.4.0beta20 [July 9, 2008]
+ Moved several PNG_HAVE_* macros from pngpriv.h to png.h because applications
+ calling set_unknown_chunk_location() need them.
+ Moved several macro definitions from pngpriv.h to pngconf.h
+ Merge with changes to the 1.2.X branch, as of 1.2.30beta04.
+ Deleted all use of the MMX assembler code and Intel-licensed optimizations.
+ Revised makefile.mingw
+
+Version 1.4.0beta21 [July 21, 2008]
+ Moved local array "chunkdata" from pngrutil.c to the png_struct, so
+ it will be freed by png_read_destroy() in case of a read error (Kurt
+ Christensen).
+
+Version 1.4.0beta22 [July 21, 2008]
+ Change "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking.
+
+Version 1.4.0beta23 [July 22, 2008]
+ Change "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in
+ png_decompress_chunk().
+
+Version 1.4.0beta24 [July 25, 2008]
+ Change all remaining "chunkdata" to "png_ptr->chunkdata" in
+ png_decompress_chunk(), and remove "chunkdata" from parameter list.
+ Put a call to png_check_chunk_name() in png_read_chunk_header().
+ Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
+ Removed two calls to png_check_chunk_name() occuring later in the process.
+ Define PNG_NO_ERROR_NUMBERS by default in pngconf.h
+
+Version 1.4.0beta25 [July 30, 2008]
+ Added a call to png_check_chunk_name() in pngpread.c
+ Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte.
+ Added png_push_have_buffer() function to pngpread.c
+ Eliminated PNG_BIG_ENDIAN_SUPPORTED and associated png_get_* macros.
+ Made inline expansion of png_get_*() optional with PNG_USE_READ_MACROS.
+ Eliminated all PNG_USELESS_TESTS and PNG_CORRECT_PALETTE_SUPPORTED code.
+ Synced contrib directory and configure files with libpng-1.2.30beta06.
+ Eliminated no-longer-used pngdefs.h (but it's still built in the makefiles)
+ Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c
+
+Version 1.4.0beta26 [August 4, 2008]
+ Removed png_push_have_buffer() function in pngpread.c. It increased the
+ compiled library size slightly.
+ Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta)
+ Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings.
+ Updated contrib/visupng/cexcept.h to version 2.0.1
+ Added PNG_LITERAL_CHARACTER macros for #, [, and ].
+
+Version 1.4.0beta27 [August 5, 2008]
+ Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+ Moved newline character from individual png_debug messages into the
+ png_debug macros.
+ Allow user to #define their own png_debug, png_debug1, and png_debug2.
+
+Version 1.4.0beta28 [August 5, 2008]
+ Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+ Added PNG_STRING_NEWLINE macro
+
+Version 1.4.0beta29 [August 9, 2008]
+ Revised usage of PNG_STRING_NEWLINE to work on non-ISO compilers.
+ Added PNG_STRING_COPYRIGHT macro.
+ Added non-ISO versions of png_debug macros.
+
+Version 1.4.0beta30 [August 14, 2008]
+ Added premultiplied alpha feature (Volker Wiendl).
+
+Version 1.4.0beta31 [August 18, 2008]
+ Moved png_set_premultiply_alpha from pngtrans.c to pngrtran.c
+ Removed extra crc check at the end of png_handle_cHRM(). Bug introduced
+ in libpng-1.4.0beta20.
+
+Version 1.4.0beta32 [August 19, 2008]
+ Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call.
+ Revised PNG_NO_STDIO version of png_write_flush()
+
+Version 1.4.0beta33 [August 20, 2008]
+ Added png_get|set_chunk_cache_max() to limit the total number of sPLT,
+ text, and unknown chunks that can be stored.
+
+Version 1.4.0beta34 [September 6, 2008]
+ Shortened tIME_string to 29 bytes in pngtest.c
+ Fixed off-by-one error introduced in png_push_read_zTXt() function in
+ libpng-1.2.30beta04/pngpread.c (Harald van Dijk)
+
+Version 1.4.0beta35 [October 6, 2008]
+ Changed "trans_values" to "trans_color".
+ Changed so-number from 0 to 14. Some OS do not like 0.
+ Revised makefile.darwin to fix shared library numbering.
+ Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8()
+ in example.c (debian bug report)
+
+Version 1.4.0beta36 [October 25, 2008]
+ Sync with tEXt vulnerability fix in libpng-1.2.33rc02.
+
+Version 1.4.0beta37 [November 13, 2008]
+ Added png_check_cHRM in png.c and moved checking from pngget.c, pngrutil.c,
+ and pngwrite.c
+
+Version 1.4.0beta38 [November 22, 2008]
+ Added check for zero-area RGB cHRM triangle in png_check_cHRM() and
+ png_check_cHRM_fixed().
+
+Version 1.4.0beta39 [November 23, 2008]
+ Revised png_warning() to write its message on standard output by default
+ when warning_fn is NULL.
+
+Version 1.4.0beta40 [November 24, 2008]
+ Eliminated png_check_cHRM(). Instead, always use png_check_cHRM_fixed().
+ In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant
+ check for all-zero coordinates that is detected by the triangle check.
+
+Version 1.4.0beta41 [November 26, 2008]
+ Fixed string vs pointer-to-string error in png_check_keyword().
+ Rearranged test expressions in png_check_cHRM_fixed() to avoid internal
+ overflows.
+ Added PNG_NO_CHECK_cHRM conditional.
+
+Version 1.4.0beta42, 43 [December 1, 2008]
+ Merge png_debug with version 1.2.34beta04.
+
+Version 1.4.0beta44 [December 6, 2008]
+ Removed redundant check for key==NULL before calling png_check_keyword()
+ to ensure that new_key gets initialized and removed extra warning
+ (Merge with version 1.2.34beta05 -- Arvan Pritchard).
+
+Version 1.4.0beta45 [December 9, 2008]
+ In png_write_png(), respect the placement of the filler bytes in an earlier
+ call to png_set_filler() (Jim Barry).
+
+Version 1.4.0beta46 [December 10, 2008]
+ Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and
+ PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated
+ PNG_TRANSFORM_STRIP_FILLER (Jim Barry).
+
+Version 1.4.0beta47 [December 15, 2008]
+ Support for dithering was disabled by default, because it has never
+ been well tested and doesn't work very well. The code has not
+ been removed, however, and can be enabled by building libpng with
+ PNG_READ_DITHER_SUPPORTED defined.
+
+Version 1.4.0beta48 [February 14, 2009]
+ Added new exported function png_calloc().
+ Combined several instances of png_malloc(); png_memset() into png_calloc().
+ Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+ but was never defined.
+
+Version 1.4.0beta49 [February 28, 2009]
+ Added png_fileno() macro to pngconf.h, used in pngwio.c
+ Corrected order of #ifdef's in png_debug definition in png.h
+ Fixed bug introduced in libpng-1.4.0beta48 with the memset arguments
+ for pcal_params.
+ Fixed order of #ifdef directives in the png_debug defines in png.h
+ (bug introduced in libpng-1.2.34/1.4.0beta29).
+ Revised comments in png_set_read_fn() and png_set_write_fn().
+
+Version 1.4.0beta50 [March 18, 2009]
+ Use png_calloc() instead of png_malloc() to allocate big_row_buf when
+ reading an interlaced file, to avoid a possible UMR.
+ Undid revision of PNG_NO_STDIO version of png_write_flush(). Users
+ having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined
+ or supply their own flush_fn() replacement.
+ Revised libpng*.txt and png.h documentation about use of png_write_flush()
+ and png_set_write_fn().
+ Removed fflush() from pngtest.c.
+ Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+
+Version 1.4.0beta51 [March 21, 2009]
+ Removed new png_fileno() macro from pngconf.h .
+
+Version 1.4.0beta52 [March 27, 2009]
+ Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
+ This avoids building 16-bit gamma tables unnecessarily.
+ Removed fflush() from pngtest.c.
+ Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+ Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt
+
+Version 1.4.0beta53 [April 1, 2009]
+ Removed some remaining MMX macros from pngpriv.h
+ Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles)
+
+Version 1.4.0beta54 [April 13, 2009]
+ Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow
+ application code writers to bypass the check for multiple inclusion
+ of setjmp.h when they know that it is safe to ignore the situation.
+ Eliminated internal use of setjmp() in pngread.c and pngwrite.c
+ Reordered ancillary chunks in pngtest.png to be the same as what
+ pngtest now produces, and made some cosmetic changes to pngtest output.
+ Eliminated deprecated png_read_init_3() and png_write_init_3() functions.
+
+Version 1.4.0beta55 [April 15, 2009]
+ Simplified error handling in pngread.c and pngwrite.c by putting
+ the new png_read_cleanup() and png_write_cleanup() functions inline.
+
+Version 1.4.0beta56 [April 25, 2009]
+ Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress
+ "shadowed declaration" warning from gcc-4.3.3.
+ Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration"
+ warning about a global "gamma" variable in math.h on some platforms.
+
+Version 1.4.0beta57 [May 2, 2009]
+ Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+ but was never defined (again).
+ Rebuilt configure scripts with autoconf-2.63 instead of 2.62
+ Removed pngprefs.h and MMX from makefiles
+
+Version 1.4.0beta58 [May 14, 2009]
+ Changed pngw32.def to pngwin.def in makefile.mingw (typo was introduced
+ in beta57).
+ Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
+
+Version 1.4.0beta59 [May 15, 2009]
+ Reformated sources in libpng style (3-space intentation, comment format)
+ Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG)
+ Added sections about the git repository and our coding style to the
+ documentation
+ Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
+
+Version 1.4.0beta60 [May 19, 2009]
+ Conditionally compile png_read_finish_row() which is not used by
+ progressive readers.
+ Added contrib/pngminim/preader to demonstrate building minimal progressive
+ decoder, based on contrib/gregbook with embedded libpng and zlib.
+
+Version 1.4.0beta61 [May 20, 2009]
+ In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
+ is only one makefile in those directories, and revised the README files
+ accordingly.
+ More reformatting of comments, mostly to capitalize sentences.
+
+Version 1.4.0beta62 [June 2, 2009]
+ Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
+ and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
+ Reformatted several remaining "else statement" into two lines.
+ Added a section to the libpng documentation about using png_get_io_ptr()
+ in configure scripts to detect the presence of libpng.
+
+Version 1.4.0beta63 [June 15, 2009]
+ Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
+ multiple times and to specify the sample order in the tRNS chunk,
+ because the ISO PNG specification has a typo in the tRNS table.
+ Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to
+ PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism
+ available for ignoring known chunks even when not saving unknown chunks.
+ Adopted preference for consistent use of "#ifdef" and "#ifndef" versus
+ "#if defined()" and "if !defined()" where possible.
+
+Version 1.4.0beta64 [June 24, 2009]
+ Eliminated PNG_LEGACY_SUPPORTED code.
+ Moved the various unknown chunk macro definitions outside of the
+ PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
+
+Version 1.4.0beta65 [June 26, 2009]
+ Added a reference to the libpng license in each file.
+
+Version 1.4.0beta66 [June 27, 2009]
+ Refer to the libpng license instead of the libpng license in each file.
+
+Version 1.4.0beta67 [July 6, 2009]
+ Relocated INVERT_ALPHA within png_read_png() and png_write_png().
+ Added high-level API transform PNG_TRANSFORM_GRAY_TO_RGB.
+ Added an "xcode" project to the projects directory (Alam Arias).
+
+Version 1.4.0beta68 [July 19, 2009]
+ Avoid some tests in filter selection in pngwutil.c
+
+Version 1.4.0beta69 [July 25, 2009]
+ Simplified the new filter-selection test. This runs faster in the
+ common "PNG_ALL_FILTERS" and PNG_FILTER_NONE cases.
+ Removed extraneous declaration from the new call to png_read_gray_to_rgb()
+ (bug introduced in libpng-1.4.0beta67).
+ Fixed up xcode project (Alam Arias)
+ Added a prototype for png_64bit_product() in png.c
+
+Version 1.4.0beta70 [July 27, 2009]
+ Avoid a possible NULL dereference in debug build, in png_set_text_2().
+ (bug introduced in libpng-0.95, discovered by Evan Rouault)
+
+Version 1.4.0beta71 [July 29, 2009]
+ Rebuilt configure scripts with autoconf-2.64.
+
+Version 1.4.0beta72 [August 1, 2009]
+ Replaced *.tar.lzma with *.tar.xz in distribution. Get the xz codec
+ from <http://tukaani.org/xz>.
+
+Version 1.4.0beta73 [August 1, 2009]
+ Reject attempt to write iCCP chunk with negative embedded profile length
+ (JD Chen)
+
+Version 1.4.0beta74 [August 8, 2009]
+ Changed png_ptr and info_ptr member "trans" to "trans_alpha".
+
+Version 1.4.0beta75 [August 21, 2009]
+ Removed an extra png_debug() recently added to png_write_find_filter().
+ Fixed incorrect #ifdef in pngset.c regarding unknown chunk support.
+
+Version 1.4.0beta76 [August 22, 2009]
+ Moved an incorrectly located test in png_read_row() in pngread.c
+
+Version 1.4.0beta77 [August 27, 2009]
+ Removed lpXYZ.tar.bz2 (with CRLF), KNOWNBUG, libpng-x.y.z-KNOWNBUG.txt,
+ and the "noconfig" files from the distribution.
+ Moved CMakeLists.txt from scripts into the main libpng directory.
+ Various bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+
+Version 1.4.0beta78 [August 31, 2009]
+ Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h
+ Eliminated PNG_NO_FREE_ME and PNG_FREE_ME_SUPPORTED macros.
+ Use png_malloc plus a loop instead of png_calloc() to initialize
+ row_pointers in png_read_png().
+
+Version 1.4.0beta79 [September 1, 2009]
+ Eliminated PNG_GLOBAL_ARRAYS and PNG_LOCAL_ARRAYS; always use local arrays.
+ Eliminated PNG_CALLOC_SUPPORTED macro and always provide png_calloc().
+
+Version 1.4.0beta80 [September 17, 2009]
+ Removed scripts/libpng.icc
+ Changed typecast of filler from png_byte to png_uint_16 in png_set_filler().
+ (Dennis Gustafsson)
+ Fixed typo introduced in beta78 in pngtest.c ("#if def " should be "#ifdef ")
+
+Version 1.4.0beta81 [September 23, 2009]
+ Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
+ Expanded TAB characters in pngrtran.c
+ Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
+ compiler complaints about doubly declaring things "const".
+ Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
+ Eliminated unused png_ptr->row_buf_size
+
+Version 1.4.0beta82 [September 25, 2009]
+ Moved redundant IHDR checking into new png_check_IHDR() in png.c
+ and report all errors found in the IHDR data.
+ Eliminated useless call to png_check_cHRM() from pngset.c
+
+Version 1.4.0beta83 [September 25, 2009]
+ Revised png_check_IHDR() to eliminate bogus complaint about filter_type.
+
+Version 1.4.0beta84 [September 30, 2009]
+ Fixed some inconsistent indentation in pngconf.h
+ Revised png_check_IHDR() to add a test for width variable less than 32-bit.
+
+Version 1.4.0beta85 [October 1, 2009]
+ Revised png_check_IHDR() again, to check info_ptr members instead of
+ the contents of the returned parameters.
+
+Version 1.4.0beta86 [October 9, 2009]
+ Updated the "xcode" project (Alam Arias).
+ Eliminated a shadowed declaration of "pp" in png_handle_sPLT().
+
+Version 1.4.0rc01 [October 19, 2009]
+ Trivial cosmetic changes.
+
+Version 1.4.0beta87 [October 30, 2009]
+ Moved version 1.4.0 back into beta.
+
+Version 1.4.0beta88 [October 30, 2009]
+ Revised libpng*.txt section about differences between 1.2.x and 1.4.0
+ because most of the new features have now been ported back to 1.2.41
+
+Version 1.4.0beta89 [November 1, 2009]
+ More bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+ Removed a harmless extra png_set_invert_alpha() from pngwrite.c
+ Apply png_user_chunk_cache_max within png_decompress_chunk().
+ Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate.
+
+Version 1.4.0beta90 [November 2, 2009]
+ Removed all remaining WIN32_WCE #ifdefs except those involving the
+ time.h "tm" structure
+
+Version 1.4.0beta91 [November 3, 2009]
+ Updated scripts/pngw32.def and projects/wince/png32ce.def
+ Copied projects/wince/png32ce.def to the scripts directory.
+ Added scripts/makefile.wce
+ Patched ltmain.sh for wince support.
+ Added PNG_CONVERT_tIME_SUPPORTED macro.
+
+Version 1.4.0beta92 [November 4, 2009]
+ Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED
+ Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED
+ Revised libpng*.txt to describe differences from 1.2.40 to 1.4.0 (instead
+ of differences from 1.2.41 to 1.4.0)
+
+Version 1.4.0beta93 [November 7, 2009]
+ Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
+ PNG_ALLOCATED macros to detect deprecated direct access to the
+ png_struct or info_struct members and other deprecated usage in
+ applications (John Bowler).
+ Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS,
+ to prevent warnings about direct access to png structs by libpng
+ functions while building libpng. They need to be tested, especially
+ those using compilers other than gcc.
+ Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG".
+ They should work but still need to be updated to remove
+ references to pnggccrd.c or pngvcrd.c and ASM building.
+ Added README.txt to the beos, cbuilder5, netware, and xcode projects warning
+ that they need to be updated, to remove references to pnggccrd.c and
+ pngvcrd.c and to depend on pngpriv.h
+ Removed three direct references to read_info_ptr members in pngtest.c
+ that were detected by the new PNG_DEPSTRUCT macro.
+ Moved the png_debug macro definitions and the png_read_destroy(),
+ png_write_destroy() and png_far_to_near() prototypes from png.h
+ to pngpriv.h (John Bowler)
+ Moved the synopsis lines for png_read_destroy(), png_write_destroy()
+ png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3.
+
+Version 1.4.0beta94 [November 9, 2009]
+ Removed the obsolete, unused pnggccrd.c and pngvcrd.c files.
+ Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions.
+ Removed dependency of pngtest.o on pngpriv.h in the makefiles.
+ Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined.
+
+Version 1.4.0beta95 [November 10, 2009]
+ Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+ Added -DPNG_CONFIGURE_LIBPNG to contrib/pngminm/*/makefile
+ Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+ Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c
+ Changed pngminim/*/gather.sh to stop trying to remove pnggccrd.c and pngvcrd.c
+ Added dependency on pngpriv.h in contrib/pngminim/*/makefile
+
+Version 1.4.0beta96 [November 12, 2009]
+ Renamed scripts/makefile.wce to scripts/makefile.cegcc
+ Revised Makefile.am to use libpng.sys while building libpng.so
+ so that only PNG_EXPORT functions are exported.
+ Removed the deprecated png_check_sig() function/macro.
+ Removed recently removed function names from scripts/*.def
+ Revised pngtest.png to put chunks in the same order written by pngtest
+ (evidently the same change made in libpng-1.0beta54 was lost).
+ Added PNG_PRIVATE macro definition in pngconf.h for possible future use.
+
+Version 1.4.0beta97 [November 13, 2009]
+ Restored pngtest.png to the libpng-1.4.0beta7 version.
+ Removed projects/beos and netware.txt; no one seems to be supporting them.
+ Revised Makefile.in
+
+Version 1.4.0beta98 [November 13, 2009]
+ Added the "xcode" project to zip distributions,
+ Fixed a typo in scripts/pngwin.def introduced in beta97.
+
+Version 1.4.0beta99 [November 14, 2009]
+ Moved libpng-config.in and libpng.pc-configure.in out of the scripts
+ directory, to libpng-config.in and libpng-pc.in, respectively, and
+ modified Makefile.am and configure.ac accordingly. Now "configure"
+ needs nothing from the "scripts" directory.
+ Avoid redefining PNG_CONST in pngconf.h
+
+Version 1.4.0beta100 [November 14, 2009]
+ Removed ASM builds from projects/visualc6 and projects/visualc71
+ Removed scripts/makefile.nommx and makefile.vcawin32
+ Revised CMakeLists.txt to account for new location of libpng-config.in
+ and libpng-pc.in
+ Updated INSTALL to reflect removal and relocation of files.
+
+Version 1.4.0beta101 [November 14, 2009]
+ Restored the binary files (*.jpg, *.png, some project files) that were
+ accidentally deleted from the zip and 7z distributions when the xcode
+ project was added.
+
+Version 1.4.0beta102 [November 18, 2009]
+ Added libpng-config.in and libpng-pc.in to the zip and 7z distributions.
+ Fixed a typo in projects/visualc6/pngtest.dsp, introduced in beta100.
+ Moved descriptions of makefiles and other scripts out of INSTALL into
+ scripts/README.txt
+ Updated the copyright year in scripts/pngwin.rc from 2006 to 2009.
+
+Version 1.4.0beta103 [November 21, 2009]
+ Removed obsolete comments about ASM from projects/visualc71/README_zlib.txt
+ Align row_buf on 16-byte boundary in memory.
+ Restored the PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED guard around the call
+ to png_flush() after png_write_IEND(). See 1.4.0beta32, 1.4.0beta50
+ changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41 CHANGES. Someone
+ needs this feature.
+ Make the 'png_jmpbuf' macro expand to a call that records the correct
+ longjmp function as well as returning a pointer to the setjmp
+ jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'.
+ (John Bowler)
+
+Version 1.4.0beta104 [November 22, 2009]
+ Removed png_longjmp_ptr from scripts/*.def and libpng.3
+ Rebuilt configure scripts with autoconf-2.65
+
+Version 1.4.0beta105 [November 25, 2009]
+ Use fast integer PNG_DIVIDE_BY_255() or PNG_DIVIDE_BY_65535()
+ to accomplish alpha premultiplication when
+ PNG_READ_COMPOSITE_NODIV_SUPPORTED is defined.
+ Changed "/255" to "/255.0" in background calculations to make it clear
+ that the 255 is used as a double.
+
+Version 1.4.0beta106 [November 27, 2009]
+ Removed premultiplied alpha feature.
+
+Version 1.4.0beta107 [December 4, 2009]
+ Updated README
+ Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files.
+ Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects.
+ Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco
+ to put png.h and pngconf.h in $prefix/include, like the other scripts,
+ instead of in $prefix/include/libpng. Also revised makefile.sco
+ to put them in $prefix/include/libpng15 instead of in
+ $prefix/include/libpng/libpng15.
+
+Version 1.4.0beta108 [December 11, 2009]
+ Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile
+ Relocated png_do_chop() to its original position in pngrtran.c; the
+ change in version 1.2.41beta08 caused transparency to be handled wrong
+ in some 16-bit datastreams (Yusaku Sugai).
+
+Version 1.4.0beta109 [December 13, 2009]
+ Added "bit_depth" parameter to the private png_build_gamma_table() function.
+ Pass bit_depth=8 to png_build_gamma_table() when bit_depth is 16 but the
+ PNG_16_TO_8 transform has been set, to avoid unnecessary build of 16-bit
+ tables.
+
+Version 1.4.0rc02 [December 20, 2009]
+ Declared png_cleanup_needed "volatile" in pngread.c and pngwrite.c
+
+Version 1.4.0rc03 [December 22, 2009]
+ Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt
+ (revising the change in 1.4.0beta99)
+
+Version 1.4.0rc04 [December 25, 2009]
+ Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ in pngset.c to be consistent with other changes in version 1.2.38.
+
+Version 1.4.0rc05 [December 25, 2009]
+ Changed "libpng-pc.in" to "libpng.pc.in" in configure.ac, configure, and
+ Makefile.in to be consistent with changes in libpng-1.4.0rc03
+
+Version 1.4.0rc06 [December 29, 2009]
+ Reverted the gamma_table changes from libpng-1.4.0beta109.
+ Fixed some indentation errors.
+
+Version 1.4.0rc07 [January 1, 2010]
+ Revised libpng*.txt and libpng.3 about 1.2.x->1.4.x differences.
+ Use png_calloc() instead of png_malloc(); png_memset() in pngrutil.c
+ Update copyright year to 2010.
+
+Version 1.4.0rc08 [January 2, 2010]
+ Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr
+ in pngtest.c
+
+Version 1.4.0 [January 3, 2010]
+ No changes.
+
+Version 1.4.1beta01 [January 8, 2010]
+ Updated CMakeLists.txt for consistent indentation and to avoid an
+ unclosed if-statement warning (Philip Lowman).
+ Revised Makefile.am and Makefile.in to remove references to Y2KINFO,
+ KNOWNBUG, and libpng.la (Robert Schwebel).
+ Revised the makefiles to install the same files and symbolic
+ links as configure, except for libpng.la and libpng14.la.
+ Make png_set|get_compression_buffer_size() available even when
+ PNG_WRITE_SUPPORTED is not enabled.
+ Revised Makefile.am and Makefile.in to simplify their maintenance.
+ Revised scripts/makefile.linux to install a link to libpng14.so.14.1
+
+Version 1.4.1beta02 [January 9, 2010]
+ Revised the rest of the makefiles to install a link to libpng14.so.14.1
+
+Version 1.4.1beta03 [January 10, 2010]
+ Removed png_set_premultiply_alpha() from scripts/*.def
+
+Version 1.4.1rc01 [January 16, 2010]
+ No changes.
+
+Version 1.4.1beta04 [January 23, 2010]
+ Revised png_decompress_chunk() to improve speed and memory usage when
+ decoding large chunks.
+ Added png_set|get_chunk_malloc_max() functions.
+
+Version 1.4.1beta05 [January 26, 2010]
+ Relocated "int k" declaration in pngtest.c to minimize its scope.
+
+Version 1.4.1beta06 [January 28, 2010]
+ Revised png_decompress_chunk() to use a two-pass method suggested by
+ John Bowler.
+
+Version 1.4.1beta07 [February 6, 2010]
+ Folded some long lines in the source files.
+ Added defineable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
+ and a PNG_USER_LIMITS_SUPPORTED flag.
+ Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as
+ png_ptr->png_user_chunk_malloc_max.
+ Revised png_push_save_buffer() to do fewer but larger png_malloc() calls.
+
+Version 1.4.1beta08 [February 6, 2010]
+ Minor cleanup and updating of dates and copyright year.
+
+Version 1.5.0beta01 [February 7, 2010]
+ Moved declaration of png_struct into private pngstruct.h and png_info
+ into pnginfo.h
+
+Version 1.4.1beta09 and 1.5.0beta02 [February 7, 2010]
+ Reverted to original png_push_save_buffer() code.
+
+Version 1.4.1beta10 and 1.5.0beta03 [February 8, 2010]
+ Return allocated "old_buffer" in png_push_save_buffer() before
+ calling png_error(), to avoid a potential memory leak.
+ Updated configure script to use SO number 15.
+
+Version 1.5.0beta04 [February 9, 2010]
+ Removed malformed "incomplete struct declaration" of png_info from png.h
+
+Version 1.5.0beta05 [February 12, 2010]
+ Removed PNG_DEPSTRUCT markup in pngstruct.h and pnginfo.h, and undid the
+ linewrapping that it entailed.
+ Revised comments in pngstruct.h and pnginfo.h and added pointers to
+ the libpng license.
+ Changed PNG_INTERNAL to PNG_EXPOSE_INTERNAL_STRUCTURES
+ Removed the cbuilder5 project, which has not been updated to 1.4.0.
+
+Version 1.4.1beta12 and 1.5.0beta06 [February 14, 2010]
+ Fixed type declaration of png_get_chunk_malloc_max() in pngget.c (Daisuke
+ Nishikawa)
+
+Version 1.5.0beta07 [omitted]
+
+Version 1.5.0beta08 [February 19, 2010]
+ Changed #ifdef PNG_NO_STDIO_SUPPORTED to #ifdef PNG_NO_CONSOLE_IO_SUPPORTED
+ wherever png_snprintf() is used to construct error and warning messages.
+ Noted in scripts/makefile.mingw that it expects to be run under MSYS.
+ Removed obsolete unused MMX-querying support from contrib/gregbook
+ Added exported png_longjmp() function.
+ Removed the AIX redefinition of jmpbuf in png.h
+ Added -D_ALLSOURCE in configure.ac, makefile.aix, and CMakeLists.txt
+ when building on AIX.
+
+Version 1.5.0beta09 [February 19, 2010]
+ Removed -D_ALLSOURCE from configure.ac, makefile.aix, and CMakeLists.txt.
+ Changed the name of png_ptr->jmpbuf to png_ptr->png_jmpbuf in pngstruct.h
+
+Version 1.5.0beta10 [February 25, 2010]
+ Removed unused gzio.c from contrib/pngminim gather and makefile scripts
+ Removed replacement error handlers from contrib/gregbook. Because of
+ the new png_longjmp() function they are no longer needed.
+
+Version 1.5.0beta11 [March 6, 2010]
+ Removed checking for already-included setjmp.h from pngconf.h
+ Fixed inconsistent indentations and made numerous cosmetic changes.
+ Revised the "SEE ALSO" style of libpng.3, libpngpf.3, and png.5
+
+Version 1.5.0beta12 [March 9, 2010]
+ Moved "#include png.h" inside pngpriv.h and removed "#include png.h" from
+ the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES"
+ and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler).
+ Created new pngdebug.h and moved debug definitions there.
+
+Version 1.5.0beta13 [March 10, 2010]
+ Protect pngstruct.h, pnginfo.h, and pngdebug.h from being included twice.
+ Revise the "#ifdef" blocks in png_inflate() so it will compile when neither
+ PNG_USER_CHUNK_MALLOC_MAX nor PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+ is defined.
+ Removed unused png_measure_compressed_chunk() from pngpriv.h and libpngpf.3
+ Moved the 'config.h' support from pngconf.h to pngpriv.h
+ Removed PNGAPI from the png_longjmp_ptr typedef.
+ Eliminated dependence of pngtest.c on the private pngdebug.h file.
+ Make all png_debug macros into *unterminated* statements or
+ expressions (i.e. a trailing ';' must always be added) and correct
+ the format statements in various png_debug messages.
+
+Version 1.5.0beta14 [March 14, 2010]
+ Removed direct access to png_ptr->io_ptr from the Windows code in pngtest.c
+ Revised Makefile.am to account for recent additions and replacements.
+ Corrected CE and OS/2 DEF files (scripts/png*def) for symbols removed and
+ added ordinal numbers to the Windows DEF file and corrected the duplicated
+ ordinal numbers on CE symbols that are commented out.
+ Added back in export symbols that can be present in the Windows build but
+ are disabled by default.
+ PNG_EXPORT changed to include an 'ordinal' field for DEF file generation.
+ PNG_CALLBACK added to make callback definitions uniform. PNGAPI split
+ into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
+ and appropriate changes made to all files. Cygwin builds re-hinged to
+ allow procedure call standard changes and to remove the need for the DEF
+ file (fixes build on Cygwin).
+ Enabled 'attribute' warnings that are relevant to library APIs and callbacks.
+ Changed rules for generation of the various symbol files and added a new
+ rule for a DEF file (which is also added to the distribution).
+ Updated the symbol file generation to stop it adding spurious spaces
+ to EOL (coming from preprocessor macro expansion). Added a facility
+ to join tokens in the output and rewrite *.dfn to use this.
+ Eliminated scripts/*.def in favor of libpng.def; updated projects/visualc71
+ and removed scripts/makefile.cygwin.
+ Made PNG_BUILD_DLL safe: it can be set whenever a DLL is being built.
+ Removed the include of sys/types.h - apparently unnecessary now on the
+ platforms on which it happened (all but Mac OS and RISC OS).
+ Moved the Mac OS test into pngpriv.h (the only place it is used.)
+
+Version 1.5.0beta15 [March 17, 2010]
+ Added symbols.chk target to Makefile.am to validate the symbols in png.h
+ against the new DEF file scripts/symbols.def.
+ Changed the default DEF file back to pngwin.def.
+ Removed makefile.mingw.
+ Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN
+
+Version 1.5.0beta16 [April 1, 2010]
+ Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that
+ fields are initialized in all configurations. The READ/WRITE
+ macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as
+ before to disable code to actually read or write iTXt chunks
+ and iTXt_SUPPORTED can be used to detect presence of either
+ read or write support (but it is probably better to check for
+ the one actually required - read or write.)
+ Combined multiple png_warning() calls for a single error.
+ Restored the macro definition of png_check_sig().
+
+Version 1.5.0beta17 [April 17, 2010]
+ Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+ Documented the fact that png_set_dither() was disabled since libpng-1.4.0.
+ Reenabled png_set_dither() but renamed it to png_set_quantize() to reflect
+ more accurately what it actually does. At the same time, renamed
+ the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to
+ PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.
+ Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+ Freeze build-time only configuration in the build.
+ In all prior versions of libpng most configuration options
+ controlled by compiler #defines had to be repeated by the
+ application code that used libpng. This patch changes this
+ so that compilation options that can only be changed at build
+ time are frozen in the build. Options that are compiler
+ dependent (and those that are system dependent) are evaluated
+ each time - pngconf.h holds these. Options that can be changed
+ per-file in the application are in png.h. Frozen options are
+ in the new installed header file pnglibconf.h (John Bowler)
+ Removed the xcode project because it has not been updated to work
+ with libpng-1.5.0.
+ Removed the ability to include optional pngusr.h
+
+Version 1.5.0beta18 [April 17, 2010]
+ Restored the ability to include optional pngusr.h
+ Moved replacements for png_error() and png_warning() from the
+ contrib/pngminim project to pngerror.c, for use when warnings or
+ errors are disabled via PNG_NO_WARN or PNG_NO_ERROR_TEXT, to avoid
+ storing unneeded error/warning text.
+ Updated contrib/pngminim project to work with the new pnglibconf.h
+ Added some PNG_NO_* defines to contrib/pngminim/*/pngusr.h to save space.
+
+Version 1.5.0beta19 [April 24, 2010]
+ Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the functions
+ to read and write ints to be disabled independently of PNG_USE_READ_MACROS,
+ which allows libpng to be built with the functions even though the default
+ is to use the macros - this allows applications to choose at app build
+ time whether or not to use macros (previously impossible because the
+ functions weren't in the default build.)
+ Changed Windows calling convention back to __cdecl for API functions.
+ For Windows/x86 platforms only:
+ __stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses
+ __cdecl throughout (both API functions and callbacks) on Windows/x86
+ platforms.
+ Replaced visualc6 and visualc71 projects with new vstudio project
+ Relaxed the overly-restrictive permissions of some files.
+
+Version 1.5.0beta20 [April 24, 2010]
+ Relaxed more overly-restrictive permissions of some files.
+
+Version 1.5.0beta21 [April 27, 2010]
+ Removed some unwanted binary bytes and changed CRLF to NEWLINE in the new
+ vstudio project files, and some trivial editing of some files in the
+ scripts directory.
+ Set PNG_NO_READ_BGR, PNG_NO_IO_STATE, and PNG_NO_TIME_RFC1123 in
+ contrib/pngminim/decoder/pngusr.h to make a smaller decoder application.
+
+Version 1.5.0beta22 [April 28, 2010]
+ Fixed dependencies of GET_INT_32 - it does not require READ_INT_FUNCTIONS
+ because it has a macro equivalent.
+ Improved the options.awk script; added an "everything off" option.
+ Revised contrib/pngminim to use the "everything off" option in pngusr.dfa.
+
+Version 1.5.0beta23 [April 29, 2010]
+ Corrected PNG_REMOVED macro to take five arguments.
+ The macro was documented with two arguments (name,ordinal), however
+ the symbol checking .dfn files assumed five arguments. The five
+ argument form seems more useful so it is changed to that.
+ Corrected PNG_UNKNOWN_CHUNKS_SUPPORTED to PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ in gregbook/readpng2.c
+ Corrected protection of png_get_user_transform_ptr. The API declaration in
+ png.h is removed if both READ and WRITE USER_TRANSFORM are turned off
+ but was left defined in pngtrans.c
+ Added logunsupported=1 to cause pnglibconf.h to document disabled options.
+ This makes the installed pnglibconf.h more readable but causes no
+ other change. The intention is that users of libpng will find it
+ easier to understand if an API they need is missing.
+ Include png_reset_zstream() in png.c only when PNG_READ_SUPPORTED is defined.
+ Removed dummy_inflate.c from contrib/pngminim/encoder
+ Removed contrib/pngminim/*/gather.sh; gathering is now done in the makefile.
+
+Version 1.5.0beta24 [May 7, 2010]
+ Use bitwise "&" instead of arithmetic mod in pngrutil.c calculation of the
+ offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf.
+ Added more blank lines for readability.
+
+Version 1.5.0beta25 [June 18, 2010]
+ In pngpread.c: png_push_have_row() add check for new_row > height
+ Removed the now-redundant check for out-of-bounds new_row from example.c
+
+Version 1.5.0beta26 [June 18, 2010]
+ In pngpread.c: png_push_process_row() add check for too many rows.
+
+Version 1.5.0beta27 [June 18, 2010]
+ Removed the check added in beta25 as it is now redundant.
+
+Version 1.5.0beta28 [June 20, 2010]
+ Rewrote png_process_IDAT_data to consistently treat extra data as warnings
+ and handle end conditions more cleanly.
+ Removed the new (beta26) check in png_push_process_row().
+
+Version 1.5.0beta29 [June 21, 2010]
+ Revised scripts/options.awk to work on Sunos (but still doesn't work)
+ Added comment to options.awk and contrib/pngminim/*/makefile to try nawk.
+
+Version 1.5.0beta30 [June 22, 2010]
+ Stop memory leak when reading a malformed sCAL chunk.
+
+Version 1.5.0beta31 [June 26, 2010]
+ Revised pngpread.c patch of beta28 to avoid an endless loop.
+ Removed some trailing blanks.
+
+Version 1.5.0beta32 [June 26, 2010]
+ Removed leftover scripts/options.patch and scripts/options.rej
+
+Version 1.5.0beta33 [July 6, 3010]
+ Made FIXED and FLOATING options consistent in the APIs they enable and
+ disable. Corrected scripts/options.awk to handle both command line
+ options and options specified in the .dfa files.
+ Changed char *msg to PNG_CONST char *msg in pngrutil.c
+ Make png_set_sRGB_gAMA_and_cHRM set values using either the fixed or
+ floating point APIs, but not both.
+ Reversed patch to remove error handler when the jmp_buf is stored in the
+ main program structure, not the png_struct.
+ The error handler is needed because the default handler in libpng will
+ always use the jmp_buf in the library control structure; this is never
+ set. The gregbook code is a useful example because, even though it
+ uses setjmp/longjmp, it shows how error handling can be implemented
+ using control mechanisms not directly supported by libpng. The
+ technique will work correctly with mechanisms such as Microsoft
+ Structure Exceptions or C++ exceptions (compiler willing - note that gcc
+ does not by default support interworking of C and C++ error handling.)
+ Reverted changes to call png_longjmp in contrib/gregbook where it is not
+ appropriate. If mainprog->jmpbuf is used by setjmp, then png_longjmp
+ cannot be used.
+ Changed "extern PNG_EXPORT" to "PNG_EXPORT" in png.h (Jan Nijtmans)
+ Changed "extern" to "PNG_EXTERN" in pngpriv.h (except for the 'extern "C" {')
+
+Version 1.5.0beta34 [July 12, 2010]
+ Put #ifndef PNG_EXTERN, #endif around the define PNG_EXTERN in pngpriv.h
+
+Version 1.5.0beta35 [July 24, 2010]
+ Removed some newly-added TAB characters.
+ Added -DNO_PNG_SNPRINTF to CFLAGS in scripts/makefile.dj2
+ Moved the definition of png_snprintf() outside of the enclosing
+ #ifdef blocks in pngconf.h
+
+Version 1.5.0beta36 [July 29, 2010]
+ Patches by John Bowler:
+ Fixed point APIs are now supported throughout (no missing APIs).
+ Internal fixed point arithmetic support exists for all internal floating
+ point operations.
+ sCAL validates the floating point strings it is passed.
+ Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
+ Two new APIs exist to get the number of passes without turning on the
+ PNG_INTERLACE transform and to get the number of rows in the current
+ pass.
+ A new test program, pngvalid.c, validates the gamma code.
+ Errors in the 16 bit gamma correction (overflows) have been corrected.
+ cHRM chunk testing is done consistently (previously the floating point
+ API bypassed it, because the test really didn't work on FP, now the test
+ is performed on the actual values to be stored in the PNG file so it
+ works in the FP case too.)
+ Most floating point APIs now simply call the fixed point APIs after
+ converting the values to the fixed point form used in the PNG file.
+ The standard headers no longer include zlib.h, which is currently only
+ required for pngstruct.h and can therefore be internal.
+ Revised png_get_int_32 to undo the PNG two's complement representation of
+ negative numbers.
+
+Version 1.5.0beta37 [July 30, 2010]
+ Added a typecast in png_get_int_32() in png.h and pngrutil.h to avoid
+ a compiler warning.
+ Replaced oFFs 0,0 with oFFs -10,20 in pngtest.png
+
+Version 1.5.0beta38 [July 31, 2010]
+ Implemented remaining "_fixed" functions.
+ Corrected a number of recently introduced warnings mostly resulting from
+ safe but uncast assignments to shorter integers. Also added a zlib
+ VStudio release library project because the latest zlib Official Windows
+ build does not include such a thing.
+ Revised png_get_int_16() to be similar to png_get_int_32().
+ Restored projects/visualc71.
+
+Version 1.5.0beta39 [August 2, 2010]
+ VisualC/GCC warning fixes, VisualC build fixes
+ The changes include support for function attributes in VC in addition to
+ those already present in GCC - necessary because without these some
+ warnings are unavoidable. Fixes include signed/unsigned fixes in
+ pngvalid and checks with gcc -Wall -Wextra -Wunused.
+ VC requires function attributes on function definitions as well as
+ declarations, PNG_FUNCTION has been added to enable this and the
+ relevant function definitions changed.
+
+Version 1.5.0beta40 [August 6, 2010]
+ Correct use of _WINDOWS_ in pngconf.h
+ Removed png_mem_ #defines; they are no longer used.
+ Added the sRGB chunk to pngtest.png
+
+Version 1.5.0beta41 [August 11, 2010]
+ Added the cHRM chunk to pngtest.png
+ Don't try to use version-script with cygwin/mingw.
+ Revised contrib/gregbook to work under cygwin/mingw.
+
+Version 1.5.0beta42 [August 18, 2010]
+ Add .dll.a to the list of extensions to be symlinked by Makefile.am (Yaakov)
+ Made all API functions that have const arguments and constant string
+ literal pointers declare them (John Bowler).
+
+Version 1.5.0beta43 [August 20, 2010]
+ Removed spurious tabs, shorten long lines (no source change)
+ Also added scripts/chkfmt to validate the format of all the files that can
+ reasonably be validated (it is suggested to run "make distclean" before
+ checking, because some machine generated files have long lines.)
+ Reformatted the CHANGES file to be more consistent throughout.
+ Made changes to address various issues identified by GCC, mostly
+ signed/unsigned and shortening problems on assignment but also a few
+ difficult to optimize (for GCC) loops.
+ Fixed non-GCC fixed point builds. In png.c a declaration was misplaced
+ in an earlier update. Fixed to declare the auto variables at the head.
+ Use cexcept.h in pngvalid.c.
+
+Version 1.5.0beta44 [August 24, 2010]
+ Updated CMakeLists.txt to use CMAKE_INSTALL_LIBDIR variable; useful for
+ installing libpng in /usr/lib64 (Funda Wang).
+ Revised CMakeLists.txt to put the man pages in share/man/man* not man/man*
+ Revised CMakeLists.txt to make symlinks instead of copies when installing.
+ Changed PNG_LIB_NAME from pngNN to libpngNN in CMakeLists.txt (Philip Lowman)
+ Implemented memory checks within pngvalid
+ Reformatted/rearranged pngvalid.c to assist use of progressive reader.
+ Check interlaced images in pngvalid
+ Clarified pngusr.h comments in pnglibconf.dfa
+ Simplified the pngvalid error-handling code now that cexcept.h is in place.
+ Implemented progressive reader in pngvalid.c for standard tests
+ Implemented progressive read in pngvalid.c gamma tests
+ Turn on progressive reader in pngvalid.c by default and tidy code.
+
+Version 1.5.0beta45 [August 26, 2010]
+ Added an explicit make step to projects/vstudio for pnglibconf.h
+ Also corrected zlib.vcxproj into which Visual Studio had introduced
+ what it calls an "authoring error". The change to make pnglibconf.h
+ simply copies the file; in the future it may actually generate the
+ file from scripts/pnglibconf.dfa as the other build systems do.
+ Changed pngvalid to work when floating point APIs are disabled
+ Renamed the prebuilt scripts/pnglibconf.h to scripts/pnglibconf.h.prebuilt
+ Supply default values for PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX
+ in pngpriv.h in case the user neglected to define them in their pngusr.h
+
+Version 1.5.0beta46 [August 28, 2010]
+ Added new private header files to libpng_sources in CMakeLists.txt
+ Added PNG_READ_16BIT, PNG_WRITE_16BIT, and PNG_16BIT options.
+ Added reference to scripts/pnglibconf.h.prebuilt in the visualc71 project.
+
+Version 1.5.0beta47 [September 11, 2010]
+ Fixed a number of problems with 64-bit compilation reported by Visual
+ Studio 2010 (John Bowler).
+
+Version 1.5.0beta48 [October 4, 2010]
+ Updated CMakeLists.txt (Philip Lowman).
+ Revised autogen.sh to recognize and use $AUTOCONF, $AUTOMAKE, $AUTOHEADER,
+ $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
+ Fixed problem with symbols creation in Makefile.am which was assuming that
+ all versions of ccp write to standard output by default (Martin Banky). The
+ bug was introduced in libpng-1.2.9beta5.
+ Removed unused mkinstalldirs.
+
+Version 1.5.0beta49 [October 8, 2010]
+ Undid Makefile.am revision of 1.5.0beta48.
+
+Version 1.5.0beta50 [October 14, 2010]
+ Revised Makefile.in to account for mkinstalldirs being removed.
+ Added some "(unsigned long)" typecasts in printf statements in pngvalid.c.
+ Suppressed a compiler warning in png_handle_sPLT().
+ Check for out-of-range text compression mode in png_set_text().
+
+Version 1.5.0beta51 [October 15, 2010]
+ Changed embedded dates to "(PENDING RELEASE) in beta releases (and future
+ rc releases) to minimize the difference between releases.
+
+Version 1.5.0beta52 [October 16, 2010]
+ Restored some of the embedded dates (in png.h, png.c, documentation, etc.)
+
+Version 1.5.0beta53 [October 18, 2010]
+ Updated INSTALL to mention using "make maintainer-clean" and to remove
+ obsolete statement about a custom ltmain.sh
+ Disabled "color-tests" by default in Makefile.am so it will work with
+ automake versions earlier than 1.11.1
+ Use document name "libpng-manual.txt" instead of "libpng-<version>.txt"
+ to simplify version differences.
+ Removed obsolete remarks about setjmp handling from INSTALL.
+ Revised and renamed the typedef in png.h and png.c that was designed
+ to catch library and header mismatch.
+
+Version 1.5.0beta54 [November 10, 2010]
+ Require 48 bytes, not 64 bytes, for big_row_buf in overflow checks.
+ Used a consistent structure for the pngget.c functions.
+
+Version 1.5.0beta55 [November 21, 2010]
+ Revised png_get_uint_32, png_get_int_32, png_get_uint_16 (Cosmin)
+ Moved reading of file signature into png_read_sig (Cosmin)
+ Fixed atomicity of chunk header serialization (Cosmin)
+ Added test for io_state in pngtest.c (Cosmin)
+ Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
+ Changes to remove gcc warnings (John Bowler)
+ Certain optional gcc warning flags resulted in warnings in libpng code.
+ With these changes only -Wconversion and -Wcast-qual cannot be turned on.
+ Changes are trivial rearrangements of code. -Wconversion is not possible
+ for pngrutil.c (because of the widespread use of += et al on variables
+ smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
+ with pngwio.c and pngwutil.c because the 'write' callback and zlib
+ compression both fail to declare their input buffers with 'const'.
+
+Version 1.5.0beta56 [December 7, 2010]
+ Added the private PNG_UNUSED() macro definition in pngpriv.h.
+ Added some commentary about PNG_EXPORT in png.h and pngconf.h
+ Revised PNG_EXPORT() macro and added PNG_EXPORTA() macro, with the
+ objective of simplifying and improving the cosmetic appearance of png.h.
+ Fixed some incorrect "=" macro names in pnglibconf.dfa
+ Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt
+
+Version 1.5.0beta57 [December 9, 2010]
+ Documented the pngvalid gamma error summary with additional comments and
+ print statements.
+ Improved missing symbol handling in checksym.awk; symbols missing in both
+ the old and new files can now be optionally ignored, treated as errors
+ or warnings.
+ Removed references to pngvcrd.c and pnggccrd.c from the vstudio project.
+ Updated "libpng14" to "libpng15" in the visualc71 project.
+ Enabled the strip16 tests in pngvalid.`
+ Don't display test results (except PASS/FAIL) when running "make test".
+ Instead put them in pngtest-log.txt
+ Added "--with-zprefix=<string>" to configure.ac
+ Updated the prebuilt configuration files to autoconf version 2.68
+
+Version 1.5.0beta58 [December 19, 2010]
+ Fixed interlace image handling and add test cases (John Bowler)
+ Fixed the clean rule in Makefile.am to remove pngtest-log.txt
+ Made minor changes to work around warnings in gcc 3.4
+
+Version 1.5.0rc01 [December 27, 2010]
+ No changes.
+
+Version 1.5.0rc02 [December 27, 2010]
+ Eliminated references to the scripts/*.def files in project/visualc71.
+
+Version 1.5.0rc03 [December 28, 2010]
+ Eliminated scripts/*.def and revised Makefile.am accordingly
+
+Version 1.5.0rc04 [December 29, 2010]
+ Fixed bug in background transformation handling in pngrtran.c (it was
+ looking for the flag in png_ptr->transformations instead of in
+ png_ptr->flags) (David Raymond).
+
+Version 1.5.0rc05 [December 31, 2010]
+ Fixed typo in a comment in CMakeLists.txt (libpng14 => libpng15) (Cosmin)
+
+Version 1.5.0rc06 [January 4, 2011]
+ Changed the new configure option "zprefix=string" to "zlib-prefix=string"
+
+Version 1.5.0rc07 [January 4, 2011]
+ Updated copyright year.
+
+Version 1.5.0 [January 6, 2011]
+ No changes.
+
+version 1.5.1beta01 [January 8, 2011]
+ Added description of png_set_crc_action() to the manual.
+ Added a note in the manual that the type of the iCCP profile was changed
+ from png_charpp to png_bytepp in png_get_iCCP(). This change happened
+ in version 1.5.0beta36 but is not noted in the CHANGES. Similarly,
+ it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
+ Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
+ internally happens to call it with one.
+ Fixed a failure to handle palette mapped images correctly.
+
+Version 1.5.1beta02 [January 14, 2011]
+ Fixed a bug in handling of interlaced images (bero at arklinux.org).
+ Updated CMakeLists.txt (Clifford Yapp)
+
+Version 1.5.1beta03 [January 14, 2011]
+ Fixed typecasting of some png_debug() statements (Cosmin)
+
+Version 1.5.1beta04 [January 16, 2011]
+ Updated documentation of png_set|get_tRNS() (Thomas Klausner).
+ Mentioned in the documentation that applications must #include "zlib.h"
+ if they need access to anything in zlib.h, and that a number of
+ macros such as png_memset() are no longer accessible by applications.
+ Corrected pngvalid gamma test "sample" function to access all of the color
+ samples of each pixel, instead of sampling the red channel three times.
+ Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
+ warnings, and (mistakenly) changed png_exp() to exp().
+
+Version 1.5.1beta05 [January 16, 2011]
+ Changed variable names png_index, png_div, png_exp, and png_gamma to
+ char_index, divisor, exp_b10, and gamma_val, respectively, and
+ changed exp() back to png_exp().
+
+Version 1.5.1beta06 [January 20, 2011]
+ Prevent png_push_crc_skip() from hanging while reading an unknown chunk
+ or an over-large compressed zTXt chunk with the progressive reader.
+ Eliminated more GCC "shadow" warnings.
+ Revised png_fixed() in png.c to avoid compiler warning about reaching the
+ end without returning anything.
+
+Version 1.5.1beta07 [January 22, 2011]
+ In the manual, describe the png_get_IHDR() arguments in the correct order.
+ Added const_png_structp and const_png_infop types, and used them in
+ prototypes for most png_get_*() functions.
+
+Version 1.5.1beta08 [January 23, 2011]
+ Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
+ Added synopses for the IO_STATE functions and other missing synopses
+ to the manual. Removed the synopses from libpngpf.3 because they
+ were out of date and no longer useful. Better information can be
+ obtained by reading the prototypes and comments in pngpriv.h
+ Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build
+ Added a make macro DFNCPP that is a CPP that will accept the tokens in
+ a .dfn file and adds configure stuff to test for such a CPP. ./configure
+ should fail if one is not available.
+ Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace.
+ Added png_get_current_row_number and png_get_current_pass_number for the
+ benefit of the user transform callback.
+ Added png_process_data_pause and png_process_data_skip for the benefit of
+ progressive readers that need to stop data processing or want to optimize
+ skipping of unread data (e.g., if the reader marks a chunk to be skipped.)
+
+Version 1.5.1beta09 [January 24, 2011]
+ Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error.
+ pngvalid contains tests of transforms, which tests are currently disabled
+ because they are incompletely tested. gray_to_rgb was failing to expand
+ the bit depth for smaller bit depth images; this seems to be a long
+ standing error and resulted, apparently, in invalid output. The
+ documentation did not accurately describe what libpng really does when
+ converting RGB to gray.
+
+Version 1.5.1beta10 [January 27, 2010]
+ Fixed incorrect examples of callback prototypes in the manual, that were
+ introduced in libpng-1.0.0.
+ In addition the order of the png_get_uint macros with respect to the
+ relevant function definitions has been reversed. This helps the
+ preprocessing of the symbol files be more robust. Furthermore, the
+ symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when
+ the library may actually be built with PNG_USE_READ_MACROS; this stops
+ the read macros interfering with the symbol file format.
+ Made the manual, synopses, and function prototypes use the function
+ argument names file_gamma, int_file_gamma, and srgb_intent consistently.
+
+Version 1.5.1beta11 [January 28, 2011]
+ Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
+ Corrected local variable type in new API png_process_data_skip()
+ The type was self-evidently incorrect but only causes problems on 64 bit
+ architectures.
+ Added transform tests to pngvalid and simplified the arguments.
+
+Version 1.5.1rc01 [January 29, 2011]
+ No changes.
+
+Version 1.5.1rc02 [January 31, 2011]
+ Added a request in the manual that applications do not use "png_" or
+ "PNG_" to begin any of their own symbols.
+ Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
+
+Version 1.5.1 [February 3, 2011]
+ No changes.
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+(subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe)
+or to glennrp at users.sourceforge.net
+
+Glenn R-P
+*/ }
+#endif
diff --git a/src/3rdparty/libpng/CMakeLists.txt b/src/3rdparty/libpng/CMakeLists.txt
new file mode 100644
index 0000000000..2ee5bf3384
--- /dev/null
+++ b/src/3rdparty/libpng/CMakeLists.txt
@@ -0,0 +1,406 @@
+cmake_minimum_required(VERSION 2.4.4)
+set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS true)
+
+if(UNIX AND NOT DEFINED CMAKE_BUILD_TYPE)
+ if(CMAKE_MAJOR_VERSION EQUAL 2 AND CMAKE_MINOR_VERSION EQUAL 4)
+ # workaround CMake 2.4.x bug
+ set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING
+ "Choose the type of build, options are:
+ None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used)
+ Debug
+ Release
+ RelWithDebInfo
+ MinSizeRel.")
+ else()
+ set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING
+ "Choose the type of build, options are:
+ None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used)
+ Debug
+ Release
+ RelWithDebInfo
+ MinSizeRel.")
+ endif()
+endif()
+
+project(libpng C)
+enable_testing()
+
+# Copyright (C) 2007-2011 Glenn Randers-Pehrson
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+set(PNGLIB_MAJOR 1)
+set(PNGLIB_MINOR 5)
+set(PNGLIB_RELEASE 1)
+set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
+set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})
+
+# needed packages
+find_package(ZLIB REQUIRED)
+include_directories(${ZLIB_INCLUDE_DIR})
+
+if(NOT WIN32)
+ find_library(M_LIBRARY
+ NAMES m
+ PATHS /usr/lib /usr/local/lib
+ )
+ if(NOT M_LIBRARY)
+ message(STATUS
+ "math library 'libm' not found - floating point support disabled")
+ endif()
+else()
+ # not needed on windows
+ set(M_LIBRARY "")
+endif()
+
+# COMMAND LINE OPTIONS
+if(DEFINED PNG_SHARED)
+ option(PNG_SHARED "Build shared lib" ${PNG_SHARED})
+else()
+ option(PNG_SHARED "Build shared lib" ON)
+endif()
+if(DEFINED PNG_STATIC)
+ option(PNG_STATIC "Build static lib" ${PNG_STATIC})
+else()
+ option(PNG_STATIC "Build static lib" ON)
+endif()
+
+if(MINGW)
+ option(PNG_TESTS "Build pngtest" NO)
+else()
+ option(PNG_TESTS "Build pngtest" YES)
+endif()
+
+option(PNG_NO_CONSOLE_IO "FIXME" YES)
+option(PNG_NO_STDIO "FIXME" YES)
+option(PNG_DEBUG "Build with debug output" NO)
+option(PNGARG "FIXME" YES)
+#TODO:
+# PNG_CONSOLE_IO_SUPPORTED
+
+# maybe needs improving, but currently I don't know when we can enable what :)
+set(png_asm_tmp "OFF")
+if(NOT WIN32)
+ find_program(uname_executable NAMES uname PATHS /bin /usr/bin /usr/local/bin)
+ if(uname_executable)
+ exec_program(${uname_executable}
+ ARGS --machine OUTPUT_VARIABLE uname_output)
+ if("uname_output" MATCHES "^.*i[1-9]86.*$")
+ set(png_asm_tmp "ON")
+ else("uname_output" MATCHES "^.*i[1-9]86.*$")
+ set(png_asm_tmp "OFF")
+ endif("uname_output" MATCHES "^.*i[1-9]86.*$")
+ endif(uname_executable)
+else()
+ # this env var is normally only set on win64
+ set(TEXT "ProgramFiles(x86)")
+ if("$ENV{${TEXT}}" STREQUAL "")
+ set(png_asm_tmp "ON")
+ endif("$ENV{${TEXT}}" STREQUAL "")
+endif()
+
+# SET LIBNAME
+set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})
+
+# to distinguish between debug and release lib
+set(CMAKE_DEBUG_POSTFIX "d")
+
+# Use the prebuilt pnglibconf.h file from the scripts folder
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
+ ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
+include_directories(${CMAKE_CURRENT_BINARY_DIR})
+
+# OUR SOURCES
+set(libpng_public_hdrs
+ png.h
+ pngconf.h
+ ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h
+)
+set(libpng_sources
+ ${libpng_public_hdrs}
+ pngdebug.h
+ pnginfo.h
+ pngpriv.h
+ pngstruct.h
+ png.c
+ pngerror.c
+ pngget.c
+ pngmem.c
+ pngpread.c
+ pngread.c
+ pngrio.c
+ pngrtran.c
+ pngrutil.c
+ pngset.c
+ pngtrans.c
+ pngwio.c
+ pngwrite.c
+ pngwtran.c
+ pngwutil.c
+)
+set(pngtest_sources
+ pngtest.c
+)
+# SOME NEEDED DEFINITIONS
+
+add_definitions(-DPNG_CONFIGURE_LIBPNG)
+
+if(_AIX)
+ add_definitions(-D_ALL_SOURCE)
+endif(_AIX)
+
+if(MSVC)
+ add_definitions(-DPNG_NO_MODULEDEF -D_CRT_SECURE_NO_DEPRECATE)
+endif(MSVC)
+
+if(PNG_SHARED OR NOT MSVC)
+ #if building msvc static this has NOT to be defined
+ add_definitions(-DZLIB_DLL)
+endif()
+
+
+if(PNG_CONSOLE_IO_SUPPORTED)
+ add_definitions(-DPNG_CONSOLE_IO_SUPPORTED)
+endif()
+
+if(PNG_NO_CONSOLE_IO)
+ add_definitions(-DPNG_NO_CONSOLE_IO)
+endif()
+
+if(PNG_NO_STDIO)
+ add_definitions(-DPNG_NO_STDIO)
+endif()
+
+if(PNG_DEBUG)
+ add_definitions(-DPNG_DEBUG)
+endif()
+
+if(NOT M_LIBRARY AND NOT WIN32)
+ add_definitions(-DPNG_NO_FLOATING_POINT_SUPPORTED)
+endif()
+
+# NOW BUILD OUR TARGET
+include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${ZLIB_INCLUDE_DIR})
+
+if(PNG_SHARED)
+ add_library(${PNG_LIB_NAME} SHARED ${libpng_sources})
+ if(MSVC)
+ # msvc does not append 'lib' - do it here to have consistent name
+ set_target_properties(${PNG_LIB_NAME} PROPERTIES PREFIX "lib")
+ set_target_properties(${PNG_LIB_NAME} PROPERTIES IMPORT_PREFIX "lib")
+ endif()
+ target_link_libraries(${PNG_LIB_NAME} ${ZLIB_LIBRARY} ${M_LIBRARY})
+endif()
+
+if(PNG_STATIC)
+# does not work without changing name
+ set(PNG_LIB_NAME_STATIC ${PNG_LIB_NAME}_static)
+ add_library(${PNG_LIB_NAME_STATIC} STATIC ${libpng_sources})
+ if(MSVC)
+ # msvc does not append 'lib' - do it here to have consistent name
+ set_target_properties(${PNG_LIB_NAME_STATIC} PROPERTIES PREFIX "lib")
+ endif()
+ target_link_libraries(${PNG_LIB_NAME_STATIC} ${ZLIB_LIBRARY} ${M_LIBRARY})
+endif()
+
+
+if(PNG_SHARED AND WIN32)
+ set_target_properties(${PNG_LIB_NAME} PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
+endif()
+
+if(PNG_TESTS AND PNG_SHARED)
+ # does not work with msvc due to png_lib_ver issue
+ add_executable(pngtest ${pngtest_sources})
+ target_link_libraries(pngtest ${PNG_LIB_NAME})
+ add_test(pngtest ./pngtest ${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png)
+endif()
+
+#
+# Set a variable with CMake code which:
+# Creates a symlink from src to dest (if possible) or alternatively
+# copies if different.
+macro(_png_generate_symlink_code CODE SRC DEST)
+ if(WIN32 AND NOT CYGWIN)
+ set(_png_gsc_message "Copying ${SRC} to ${DEST} if needed")
+ set(_png_gsc_operation "copy_if_different")
+ else()
+ set(_png_gsc_message "Symlinking ${SRC} to ${DEST}")
+ set(_png_gsc_operation "create_symlink")
+ endif()
+
+ set(${CODE} "
+ message(STATUS \"${_png_gsc_message}\")
+ execute_process(COMMAND \${CMAKE_COMMAND} -E ${_png_gsc_operation}
+ \"${SRC}\" \"${DEST}\")
+ ")
+endmacro()
+
+# CREATE PKGCONFIG FILES
+# we use the same files like ./configure, so we have to set its vars
+if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
+ set(CMAKE_INSTALL_LIBDIR lib)
+endif(NOT DEFINED CMAKE_INSTALL_LIBDIR)
+set(prefix ${CMAKE_INSTALL_PREFIX})
+set(exec_prefix ${CMAKE_INSTALL_PREFIX})
+set(libdir ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR})
+set(includedir ${CMAKE_INSTALL_PREFIX}/include)
+set(LIBS "-lz -lm")
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
+ ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc @ONLY)
+_png_generate_symlink_code(PNG_PC_INSTALL_CODE
+ ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc
+ ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc)
+install(CODE ${PNG_PC_INSTALL_CODE})
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
+ ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config @ONLY)
+_png_generate_symlink_code(PNG_CONFIG_INSTALL_CODE
+ ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
+ ${CMAKE_CURRENT_BINARY_DIR}/libpng-config)
+install(CODE ${PNG_CONFIG_INSTALL_CODE})
+
+# SET UP LINKS
+if(PNG_SHARED)
+ set_target_properties(${PNG_LIB_NAME} PROPERTIES
+# VERSION 15.${PNGLIB_RELEASE}.1.5.1
+ VERSION 15.${PNGLIB_RELEASE}.0
+ SOVERSION 15
+ CLEAN_DIRECT_OUTPUT 1)
+endif()
+if(PNG_STATIC)
+ # MSVC doesn't use a different file extension for shared vs. static
+ # libs. We are able to change OUTPUT_NAME to remove the _static
+ # for all other platforms.
+ if(NOT MSVC)
+ set_target_properties(${PNG_LIB_NAME_STATIC} PROPERTIES
+ OUTPUT_NAME ${PNG_LIB_NAME}
+ CLEAN_DIRECT_OUTPUT 1)
+ endif()
+endif()
+
+# If CMake > 2.4.x, we set a variable used below to export
+# targets to an export file.
+# TODO: Use VERSION_GREATER after our cmake_minimum_required >= 2.6.2
+if(CMAKE_MAJOR_VERSION GREATER 1 AND CMAKE_MINOR_VERSION GREATER 4)
+ set(PNG_EXPORT_RULE EXPORT libpng)
+elseif(CMAKE_MAJOR_VERSION GREATER 2) # future proof
+ set(PNG_EXPORT_RULE EXPORT libpng)
+endif()
+
+# INSTALL
+if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
+ if(PNG_SHARED)
+ install(TARGETS ${PNG_LIB_NAME}
+ ${PNG_EXPORT_RULE}
+ RUNTIME DESTINATION bin
+ LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+ ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+
+ # Create a symlink for libpng.dll.a => libpng15.dll.a on Cygwin
+ if(CYGWIN)
+ _png_generate_symlink_code(PNG_SHARED_IMPLIB_INSTALL_CODE
+ ${PNGLIB_NAME}${CMAKE_IMPORT_LIBRARY_SUFFIX}
+ libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
+ install(CODE ${PNG_SHARED_IMPLIB_INSTALL_CODE})
+ install(FILES
+ ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}
+ DESTINATION ${CMAKE_INSTALL_LIBDIR})
+ endif()
+
+ if(NOT WIN32)
+ IF(CMAKE_LIBRARY_OUTPUT_DIRECTORY)
+ _png_generate_symlink_code(PNG_SHARED_INSTALL_CODE
+ ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${PNGLIB_NAME}${CMAKE_SHARED_LIBRARY_SUFFIX}
+ ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
+ install(CODE ${PNG_SHARED_INSTALL_CODE})
+ install(FILES
+ ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
+ DESTINATION ${CMAKE_INSTALL_LIBDIR})
+ ELSE(CMAKE_LIBRARY_OUTPUT_DIRECTORY)
+ _png_generate_symlink_code(PNG_SHARED_INSTALL_CODE
+ ${PNGLIB_NAME}${CMAKE_SHARED_LIBRARY_SUFFIX}
+ libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
+ install(CODE ${PNG_SHARED_INSTALL_CODE})
+ install(FILES
+ ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
+ DESTINATION ${CMAKE_INSTALL_LIBDIR})
+ ENDIF(CMAKE_LIBRARY_OUTPUT_DIRECTORY)
+ endif()
+ endif()
+
+ if(PNG_STATIC)
+ install(TARGETS ${PNG_LIB_NAME_STATIC}
+ ${PNG_EXPORT_RULE}
+ LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+ ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+ if(NOT WIN32 OR CYGWIN)
+ IF(CMAKE_ARCHIVE_OUTPUT_DIRECTORY)
+ _png_generate_symlink_code(PNG_STATIC_INSTALL_CODE
+${CMAKE_ARCHIVE_OUTPUT_DIRECTORY}/${PNGLIB_NAME}${CMAKE_STATIC_LIBRARY_SUFFIX}
+ ${CMAKE_ARCHIVE_OUTPUT_DIRECTORY}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
+ install(CODE ${PNG_STATIC_INSTALL_CODE})
+ install(FILES
+ ${CMAKE_ARCHIVE_OUTPUT_DIRECTORY}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
+ DESTINATION ${CMAKE_INSTALL_LIBDIR})
+ ELSE(CMAKE_ARCHIVE_OUTPUT_DIRECTORY)
+ _png_generate_symlink_code(PNG_STATIC_INSTALL_CODE
+ ${PNGLIB_NAME}${CMAKE_STATIC_LIBRARY_SUFFIX}
+ libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
+ install(CODE ${PNG_STATIC_INSTALL_CODE})
+ install(FILES
+ ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
+ DESTINATION ${CMAKE_INSTALL_LIBDIR})
+ ENDIF(CMAKE_ARCHIVE_OUTPUT_DIRECTORY)
+ endif()
+ endif()
+endif()
+
+if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL )
+ install(FILES ${libpng_public_hdrs} DESTINATION include)
+ install(FILES ${libpng_public_hdrs} DESTINATION include/${PNGLIB_NAME})
+endif()
+if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL )
+ install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config DESTINATION bin)
+ install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
+ DESTINATION bin)
+endif()
+if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
+ # Install man pages
+ if(NOT PNG_MAN_DIR)
+ set(PNG_MAN_DIR "share/man")
+ endif()
+ install(FILES libpng.3 libpngpf.3 DESTINATION ${PNG_MAN_DIR}/man3)
+ install(FILES png.5 DESTINATION ${PNG_MAN_DIR}/man5)
+ # Install pkg-config files
+ install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
+ DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+ install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
+ DESTINATION bin)
+ install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc
+ DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+ install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
+ DESTINATION bin)
+endif()
+
+# On versions of CMake that support it, create an export file CMake
+# users can include() to import our targets
+if(PNG_EXPORT_RULE AND NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL )
+ install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake)
+endif()
+
+# what's with libpng-$VER%.txt and all the extra files?
+
+
+# UNINSTALL
+# do we need this?
+
+
+# DIST
+# do we need this?
+
+# to create msvc import lib for mingw compiled shared lib
+# pexports libpng.dll > libpng.def
+# lib /def:libpng.def /machine:x86
+
diff --git a/src/3rdparty/libpng/INSTALL b/src/3rdparty/libpng/INSTALL
new file mode 100644
index 0000000000..353bfff326
--- /dev/null
+++ b/src/3rdparty/libpng/INSTALL
@@ -0,0 +1,135 @@
+
+Installing libpng
+
+On Unix/Linux and similar systems, you can simply type
+
+ ./configure [--prefix=/path]
+ make check
+ make install
+
+and ignore the rest of this document.
+
+If configure does not work on your system and you have a reasonably
+up-to-date set of tools, running ./autogen.sh before running ./configure
+may fix the problem. You can also run the individual commands in
+autogen.sh with the --force option, if supported by your version of
+the tools. To be really sure that you aren't using any of the included
+pre-built scripts, you can do this:
+
+ ./configure --enable-maintainer-mode
+ make maintainer-clean
+ ./autogen.sh
+ ./configure [--prefix=/path] [other options]
+ make
+ make install
+ make check
+
+Instead, you can use one of the custom-built makefiles in the
+"scripts" directory
+
+ cp scripts/makefile.system makefile
+ make test
+ make install
+
+The files that are presently available in the scripts directory
+are listed and described in scripts/README.txt.
+
+Or you can use one of the "projects" in the "projects" directory.
+
+Before installing libpng, you must first install zlib, if it
+is not already on your system. zlib can usually be found
+wherever you got libpng. zlib can be placed in another directory,
+at the same level as libpng.
+
+If you want to use "cmake" (see www.cmake.org), type
+
+ cmake . -DCMAKE_INSTALL_PREFIX=/path
+ make
+ make install
+
+If your system already has a preinstalled zlib you will still need
+to have access to the zlib.h and zconf.h include files that
+correspond to the version of zlib that's installed.
+
+You can rename the directories that you downloaded (they
+might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.5"
+or "zlib125") so that you have directories called "zlib" and "libpng".
+
+Your directory structure should look like this:
+
+ .. (the parent directory)
+ libpng (this directory)
+ INSTALL (this file)
+ README
+ *.h
+ *.c
+ CMakeLists.txt => "cmake" script
+ configuration files:
+ configure.ac, configure, Makefile.am, Makefile.in,
+ autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
+ libpng-config.in, aclocal.m4, config.h.in, config.sub,
+ depcomp, install-sh, mkinstalldirs, test-pngtest.sh
+ contrib
+ gregbook
+ pngminim
+ pngminus
+ pngsuite
+ visupng
+ projects
+ visualc71
+ vstudio
+ scripts
+ makefile.*
+ *.def (module definition files)
+ etc.
+ pngtest.png
+ etc.
+ zlib
+ README
+ *.h
+ *.c
+ contrib
+ etc.
+
+If the line endings in the files look funny, you may wish to get the other
+distribution of libpng. It is available in both tar.gz (UNIX style line
+endings) and zip (DOS style line endings) formats.
+
+If you are building libpng with MSVC, you can enter the
+libpng projects\visualc6 or visualc71 directory and follow the instructions
+in README.txt.
+
+Otherwise enter the zlib directory and follow the instructions in zlib/README,
+then come back here and run "configure" or choose the appropriate
+makefile.sys in the scripts directory.
+
+Copy the file (or files) that you need from the
+scripts directory into this directory, for example
+
+ MSDOS example: copy scripts\makefile.msc makefile
+ UNIX example: cp scripts/makefile.std makefile
+
+Read the makefile to see if you need to change any source or
+target directories to match your preferences.
+
+Then read pnglibconf.dfa to see if you want to make any configuration
+changes.
+
+Then just run "make" which will create the libpng library in
+this directory and "make test" which will run a quick test that reads
+the "pngtest.png" file and writes a "pngout.png" file that should be
+identical to it. Look for "9782 zero samples" in the output of the
+test. For more confidence, you can run another test by typing
+"pngtest pngnow.png" and looking for "289 zero samples" in the output.
+Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
+your output with the result shown in contrib/pngsuite/README.
+
+Most of the makefiles will allow you to run "make install" to
+put the library in its final resting place (if you want to
+do that, run "make install" in the zlib directory first if necessary).
+Some also allow you to run "make test-installed" after you have
+run "make install".
+
+Further information can be found in the README and libpng-manual.txt
+files, in the individual makefiles, in png.h, and the manual pages
+libpng.3 and png.5.
diff --git a/src/3rdparty/libpng/LICENSE b/src/3rdparty/libpng/LICENSE
new file mode 100644
index 0000000000..b28f15c74f
--- /dev/null
+++ b/src/3rdparty/libpng/LICENSE
@@ -0,0 +1,111 @@
+
+This copy of the libpng notices is provided for your convenience. In case of
+any discrepancy between this copy and the notices in the file png.h that is
+included in the libpng distribution, the latter shall prevail.
+
+COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
+
+If you modify libpng you may insert additional notices immediately following
+this sentence.
+
+This code is released under the libpng license.
+
+libpng versions 1.2.6, August 15, 2004, through 1.5.1, February 3, 2011, are
+Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
+distributed according to the same disclaimer and license as libpng-1.2.5
+with the following individual added to the list of Contributing Authors
+
+ Cosmin Truta
+
+libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
+Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
+distributed according to the same disclaimer and license as libpng-1.0.6
+with the following individuals added to the list of Contributing Authors
+
+ Simon-Pierre Cadieux
+ Eric S. Raymond
+ Gilles Vollant
+
+and with the following additions to the disclaimer:
+
+ There is no warranty against interference with your enjoyment of the
+ library or against infringement. There is no warranty that our
+ efforts or the library will fulfill any of your particular purposes
+ or needs. This library is provided with all faults, and the entire
+ risk of satisfactory quality, performance, accuracy, and effort is with
+ the user.
+
+libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
+distributed according to the same disclaimer and license as libpng-0.96,
+with the following individuals added to the list of Contributing Authors:
+
+ Tom Lane
+ Glenn Randers-Pehrson
+ Willem van Schaik
+
+libpng versions 0.89, June 1996, through 0.96, May 1997, are
+Copyright (c) 1996, 1997 Andreas Dilger
+Distributed according to the same disclaimer and license as libpng-0.88,
+with the following individuals added to the list of Contributing Authors:
+
+ John Bowler
+ Kevin Bracey
+ Sam Bushell
+ Magnus Holmgren
+ Greg Roelofs
+ Tom Tanner
+
+libpng versions 0.5, May 1995, through 0.88, January 1996, are
+Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+
+For the purposes of this copyright and license, "Contributing Authors"
+is defined as the following set of individuals:
+
+ Andreas Dilger
+ Dave Martindale
+ Guy Eric Schalnat
+ Paul Schmidt
+ Tim Wegner
+
+The PNG Reference Library is supplied "AS IS". The Contributing Authors
+and Group 42, Inc. disclaim all warranties, expressed or implied,
+including, without limitation, the warranties of merchantability and of
+fitness for any purpose. The Contributing Authors and Group 42, Inc.
+assume no liability for direct, indirect, incidental, special, exemplary,
+or consequential damages, which may result from the use of the PNG
+Reference Library, even if advised of the possibility of such damage.
+
+Permission is hereby granted to use, copy, modify, and distribute this
+source code, or portions hereof, for any purpose, without fee, subject
+to the following restrictions:
+
+1. The origin of this source code must not be misrepresented.
+
+2. Altered versions must be plainly marked as such and must not
+ be misrepresented as being the original source.
+
+3. This Copyright notice may not be removed or altered from any
+ source or altered source distribution.
+
+The Contributing Authors and Group 42, Inc. specifically permit, without
+fee, and encourage the use of this source code as a component to
+supporting the PNG file format in commercial products. If you use this
+source code in a product, acknowledgment is not required but would be
+appreciated.
+
+
+A "png_get_copyright" function is available, for convenient use in "about"
+boxes and the like:
+
+ printf("%s",png_get_copyright(NULL));
+
+Also, the PNG logo (in PNG format, of course) is supplied in the
+files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
+
+Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a
+certification mark of the Open Source Initiative.
+
+Glenn Randers-Pehrson
+glennrp at users.sourceforge.net
+February 3, 2011
diff --git a/src/3rdparty/libpng/README b/src/3rdparty/libpng/README
new file mode 100644
index 0000000000..9dd6745f0a
--- /dev/null
+++ b/src/3rdparty/libpng/README
@@ -0,0 +1,205 @@
+README for libpng version 1.5.1 - February 3, 2011 (shared library 15.0)
+See the note about version numbers near the top of png.h
+
+See INSTALL for instructions on how to install libpng.
+
+Libpng comes in several distribution formats. Get libpng-*.tar.gz,
+libpng-*.tar.xz or libpng-*.tar.bz2 if you want UNIX-style line endings
+in the text files, or lpng*.zip if you want DOS-style line endings.
+
+Version 0.89 was the first official release of libpng. Don't let the
+fact that it's the first release fool you. The libpng library has been in
+extensive use and testing since mid-1995. By late 1997 it had
+finally gotten to the stage where there hadn't been significant
+changes to the API in some time, and people have a bad feeling about
+libraries with versions < 1.0. Version 1.0.0 was released in
+March 1998.
+
+****
+Note that some of the changes to the png_info structure render this
+version of the library binary incompatible with libpng-0.89 or
+earlier versions if you are using a shared library. The type of the
+"filler" parameter for png_set_filler() has changed from png_byte to
+png_uint_32, which will affect shared-library applications that use
+this function.
+
+To avoid problems with changes to the internals of png_info_struct,
+new APIs have been made available in 0.95 to avoid direct application
+access to info_ptr. These functions are the png_set_<chunk> and
+png_get_<chunk> functions. These functions should be used when
+accessing/storing the info_struct data, rather than manipulating it
+directly, to avoid such problems in the future.
+
+It is important to note that the APIs do not make current programs
+that access the info struct directly incompatible with the new
+library. However, it is strongly suggested that new programs use
+the new APIs (as shown in example.c and pngtest.c), and older programs
+be converted to the new format, to facilitate upgrades in the future.
+****
+
+Additions since 0.90 include the ability to compile libpng as a
+Windows DLL, and new APIs for accessing data in the info struct.
+Experimental functions include the ability to set weighting and cost
+factors for row filter selection, direct reads of integers from buffers
+on big-endian processors that support misaligned data access, faster
+methods of doing alpha composition, and more accurate 16->8 bit color
+conversion.
+
+The additions since 0.89 include the ability to read from a PNG stream
+which has had some (or all) of the signature bytes read by the calling
+application. This also allows the reading of embedded PNG streams that
+do not have the PNG file signature. As well, it is now possible to set
+the library action on the detection of chunk CRC errors. It is possible
+to set different actions based on whether the CRC error occurred in a
+critical or an ancillary chunk.
+
+The changes made to the library, and bugs fixed are based on discussions
+on the PNG-implement mailing list and not on material submitted
+privately to Guy, Andreas, or Glenn. They will forward any good
+suggestions to the list.
+
+For a detailed description on using libpng, read libpng-manual.txt. For
+examples of libpng in a program, see example.c and pngtest.c. For usage
+information and restrictions (what little they are) on libpng, see
+png.h. For a description on using zlib (the compression library used by
+libpng) and zlib's restrictions, see zlib.h
+
+I have included a general makefile, as well as several machine and
+compiler specific ones, but you may have to modify one for your own needs.
+
+You should use zlib 1.0.4 or later to run this, but it MAY work with
+versions as old as zlib 0.95. Even so, there are bugs in older zlib
+versions which can cause the output of invalid compression streams for
+some images. You will definitely need zlib 1.0.4 or later if you are
+taking advantage of the MS-DOS "far" structure allocation for the small
+and medium memory models. You should also note that zlib is a
+compression library that is useful for more things than just PNG files.
+You can use zlib as a drop-in replacement for fread() and fwrite() if
+you are so inclined.
+
+zlib should be available at the same place that libpng is, or at.
+ftp://ftp.info-zip.org/pub/infozip/zlib
+
+You may also want a copy of the PNG specification. It is available
+as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find
+these at http://www.libpng.org/pub/png/documents/
+
+This code is currently being archived at libpng.sf.net in the
+[DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT)
+at GO GRAPHSUP. If you can't find it in any of those places,
+e-mail me, and I'll help you find it.
+
+If you have any code changes, requests, problems, etc., please e-mail
+them to me. Also, I'd appreciate any make files or project files,
+and any modifications you needed to make to get libpng to compile,
+along with a #define variable to tell what compiler/system you are on.
+If you needed to add transformations to libpng, or wish libpng would
+provide the image in a different way, drop me a note (and code, if
+possible), so I can consider supporting the transformation.
+Finally, if you get any warning messages when compiling libpng
+(note: not zlib), and they are easy to fix, I'd appreciate the
+fix. Please mention "libpng" somewhere in the subject line. Thanks.
+
+This release was created and will be supported by myself (of course
+based in a large way on Guy's and Andreas' earlier work), and the PNG
+development group.
+
+Send comments/corrections/commendations to png-mng-implement at
+lists.sourceforge.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe) or to glennrp at users.sourceforge.net
+
+You can't reach Guy, the original libpng author, at the addresses
+given in previous versions of this document. He and Andreas will
+read mail addressed to the png-implement list, however.
+
+Please do not send general questions about PNG. Send them to
+the (png-list at ccrc.wustl.edu, subscription required, write to
+majordomo at ccrc.wustl.edu with "subscribe png-list" in your message).
+On the other hand,
+please do not send libpng questions to that address, send them to me
+or to the png-implement list. I'll
+get them in the end anyway. If you have a question about something
+in the PNG specification that is related to using libpng, send it
+to me. Send me any questions that start with "I was using libpng,
+and ...". If in doubt, send questions to me. I'll bounce them
+to others, if necessary.
+
+Please do not send suggestions on how to change PNG. We have
+been discussing PNG for nine years now, and it is official and
+finished. If you have suggestions for libpng, however, I'll
+gladly listen. Even if your suggestion is not used immediately,
+it may be used later.
+
+Files in this distribution:
+
+ ANNOUNCE => Announcement of this version, with recent changes
+ CHANGES => Description of changes between libpng versions
+ KNOWNBUG => List of known bugs and deficiencies
+ LICENSE => License to use and redistribute libpng
+ README => This file
+ TODO => Things not implemented in the current library
+ Y2KINFO => Statement of Y2K compliance
+ example.c => Example code for using libpng functions
+ libpng.3 => manual page for libpng (includes libpng-manual.txt)
+ libpng-manual.txt => Description of libpng and its functions
+ libpngpf.3 => manual page for libpng's private functions
+ png.5 => manual page for the PNG format
+ png.c => Basic interface functions common to library
+ png.h => Library function and interface declarations (public)
+ pngpriv.h => Library function and interface declarations (private)
+ pngconf.h => System specific library configuration (public)
+ pngstruct.h => png_struct declaration (private)
+ pnginfo.h => png_info struct declaration (private)
+ pngdebug.h => debugging macros (private)
+ pngerror.c => Error/warning message I/O functions
+ pngget.c => Functions for retrieving info from struct
+ pngmem.c => Memory handling functions
+ pngbar.png => PNG logo, 88x31
+ pngnow.png => PNG logo, 98x31
+ pngpread.c => Progressive reading functions
+ pngread.c => Read data/helper high-level functions
+ pngrio.c => Lowest-level data read I/O functions
+ pngrtran.c => Read data transformation functions
+ pngrutil.c => Read data utility functions
+ pngset.c => Functions for storing data into the info_struct
+ pngtest.c => Library test program
+ pngtest.png => Library test sample image
+ pngtrans.c => Common data transformation functions
+ pngwio.c => Lowest-level write I/O functions
+ pngwrite.c => High-level write functions
+ pngwtran.c => Write data transformations
+ pngwutil.c => Write utility functions
+ contrib => Contributions
+ gregbook => source code for PNG reading and writing, from
+ Greg Roelofs' "PNG: The Definitive Guide",
+ O'Reilly, 1999
+ msvctest => Builds and runs pngtest using a MSVC workspace
+ pngminus => Simple pnm2png and png2pnm programs
+ pngsuite => Test images
+ visupng => Contains a MSVC workspace for VisualPng
+ projects => Contains project files and workspaces for
+ building a DLL
+ cbuilder5 => Contains a Borland workspace for building
+ libpng and zlib
+ visualc6 => Contains a Microsoft Visual C++ (MSVC)
+ workspace for building libpng and zlib
+ visualc71 => Contains a Microsoft Visual C++ (MSVC)
+ workspace for building libpng and zlib
+ xcode => Contains an Apple xcode
+ workspace for building libpng and zlib
+ scripts => Directory containing scripts for building libpng:
+ (see scripts/README.txt for the list of scripts)
+
+Good luck, and happy coding.
+
+-Glenn Randers-Pehrson (current maintainer, since 1998)
+ Internet: glennrp at users.sourceforge.net
+
+-Andreas Eric Dilger (former maintainer, 1996-1997)
+ Internet: adilger at enel.ucalgary.ca
+ Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/
+
+-Guy Eric Schalnat (original author and former maintainer, 1995-1996)
+ (formerly of Group 42, Inc)
+ Internet: gschal at infinet.com
diff --git a/src/3rdparty/libpng/TODO b/src/3rdparty/libpng/TODO
new file mode 100644
index 0000000000..6e1f028bd7
--- /dev/null
+++ b/src/3rdparty/libpng/TODO
@@ -0,0 +1,27 @@
+/*
+TODO - list of things to do for libpng:
+
+Final bug fixes.
+Better C++ wrapper/full C++ implementation?
+Fix problem with C++ and EXTERN "C".
+cHRM transformation.
+Remove setjmp/longjmp usage in favor of returning error codes.
+Add "grayscale->palette" transformation and "palette->grayscale" detection.
+Improved dithering.
+Multi-lingual error and warning message support.
+Complete sRGB transformation (presently it simply uses gamma=0.45455).
+Man pages for function calls.
+Better documentation.
+Better filter selection
+ (counting huffman bits/precompression? filter inertia? filter costs?).
+Histogram creation.
+Text conversion between different code pages (Latin-1 -> Mac and DOS).
+Avoid building gamma tables whenever possible.
+Use greater precision when changing to linear gamma for compositing against
+ background and doing rgb-to-gray transformation.
+Investigate pre-incremented loop counters and other loop constructions.
+Add interpolated method of handling interlacing.
+Switch to the simpler zlib (zlib/libpng) license if legally possible.
+Extend pngvalid.c to validate more of the libpng transformations.
+
+*/
diff --git a/src/3rdparty/libpng/config.guess b/src/3rdparty/libpng/config.guess
new file mode 100644
index 0000000000..dc84c68ef7
--- /dev/null
+++ b/src/3rdparty/libpng/config.guess
@@ -0,0 +1,1501 @@
+#! /bin/sh
+# Attempt to guess a canonical system name.
+# Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+# 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+# Free Software Foundation, Inc.
+
+timestamp='2009-11-20'
+
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
+# 02110-1301, USA.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+
+# Originally written by Per Bothner. Please send patches (context
+# diff format) to <config-patches@gnu.org> and include a ChangeLog
+# entry.
+#
+# This script attempts to guess a canonical system name similar to
+# config.sub. If it succeeds, it prints the system name on stdout, and
+# exits with 0. Otherwise, it exits with 1.
+#
+# You can get the latest version of this script from:
+# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD
+
+me=`echo "$0" | sed -e 's,.*/,,'`
+
+usage="\
+Usage: $0 [OPTION]
+
+Output the configuration name of the system \`$me' is run on.
+
+Operation modes:
+ -h, --help print this help, then exit
+ -t, --time-stamp print date of last modification, then exit
+ -v, --version print version number, then exit
+
+Report bugs and patches to <config-patches@gnu.org>."
+
+version="\
+GNU config.guess ($timestamp)
+
+Originally written by Per Bothner.
+Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+
+This is free software; see the source for copying conditions. There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
+
+help="
+Try \`$me --help' for more information."
+
+# Parse command line
+while test $# -gt 0 ; do
+ case $1 in
+ --time-stamp | --time* | -t )
+ echo "$timestamp" ; exit ;;
+ --version | -v )
+ echo "$version" ; exit ;;
+ --help | --h* | -h )
+ echo "$usage"; exit ;;
+ -- ) # Stop option processing
+ shift; break ;;
+ - ) # Use stdin as input.
+ break ;;
+ -* )
+ echo "$me: invalid option $1$help" >&2
+ exit 1 ;;
+ * )
+ break ;;
+ esac
+done
+
+if test $# != 0; then
+ echo "$me: too many arguments$help" >&2
+ exit 1
+fi
+
+trap 'exit 1' 1 2 15
+
+# CC_FOR_BUILD -- compiler used by this script. Note that the use of a
+# compiler to aid in system detection is discouraged as it requires
+# temporary files to be created and, as you can see below, it is a
+# headache to deal with in a portable fashion.
+
+# Historically, `CC_FOR_BUILD' used to be named `HOST_CC'. We still
+# use `HOST_CC' if defined, but it is deprecated.
+
+# Portable tmp directory creation inspired by the Autoconf team.
+
+set_cc_for_build='
+trap "exitcode=\$?; (rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null) && exit \$exitcode" 0 ;
+trap "rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null; exit 1" 1 2 13 15 ;
+: ${TMPDIR=/tmp} ;
+ { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n "$tmp" && test -d "$tmp" ; } ||
+ { test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir $tmp) ; } ||
+ { tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir $tmp) && echo "Warning: creating insecure temp directory" >&2 ; } ||
+ { echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 1 ; } ;
+dummy=$tmp/dummy ;
+tmpfiles="$dummy.c $dummy.o $dummy.rel $dummy" ;
+case $CC_FOR_BUILD,$HOST_CC,$CC in
+ ,,) echo "int x;" > $dummy.c ;
+ for c in cc gcc c89 c99 ; do
+ if ($c -c -o $dummy.o $dummy.c) >/dev/null 2>&1 ; then
+ CC_FOR_BUILD="$c"; break ;
+ fi ;
+ done ;
+ if test x"$CC_FOR_BUILD" = x ; then
+ CC_FOR_BUILD=no_compiler_found ;
+ fi
+ ;;
+ ,,*) CC_FOR_BUILD=$CC ;;
+ ,*,*) CC_FOR_BUILD=$HOST_CC ;;
+esac ; set_cc_for_build= ;'
+
+# This is needed to find uname on a Pyramid OSx when run in the BSD universe.
+# (ghazi@noc.rutgers.edu 1994-08-24)
+if (test -f /.attbin/uname) >/dev/null 2>&1 ; then
+ PATH=$PATH:/.attbin ; export PATH
+fi
+
+UNAME_MACHINE=`(uname -m) 2>/dev/null` || UNAME_MACHINE=unknown
+UNAME_RELEASE=`(uname -r) 2>/dev/null` || UNAME_RELEASE=unknown
+UNAME_SYSTEM=`(uname -s) 2>/dev/null` || UNAME_SYSTEM=unknown
+UNAME_VERSION=`(uname -v) 2>/dev/null` || UNAME_VERSION=unknown
+
+# Note: order is significant - the case branches are not exclusive.
+
+case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
+ *:NetBSD:*:*)
+ # NetBSD (nbsd) targets should (where applicable) match one or
+ # more of the tupples: *-*-netbsdelf*, *-*-netbsdaout*,
+ # *-*-netbsdecoff* and *-*-netbsd*. For targets that recently
+ # switched to ELF, *-*-netbsd* would select the old
+ # object file format. This provides both forward
+ # compatibility and a consistent mechanism for selecting the
+ # object file format.
+ #
+ # Note: NetBSD doesn't particularly care about the vendor
+ # portion of the name. We always set it to "unknown".
+ sysctl="sysctl -n hw.machine_arch"
+ UNAME_MACHINE_ARCH=`(/sbin/$sysctl 2>/dev/null || \
+ /usr/sbin/$sysctl 2>/dev/null || echo unknown)`
+ case "${UNAME_MACHINE_ARCH}" in
+ armeb) machine=armeb-unknown ;;
+ arm*) machine=arm-unknown ;;
+ sh3el) machine=shl-unknown ;;
+ sh3eb) machine=sh-unknown ;;
+ sh5el) machine=sh5le-unknown ;;
+ *) machine=${UNAME_MACHINE_ARCH}-unknown ;;
+ esac
+ # The Operating System including object format, if it has switched
+ # to ELF recently, or will in the future.
+ case "${UNAME_MACHINE_ARCH}" in
+ arm*|i386|m68k|ns32k|sh3*|sparc|vax)
+ eval $set_cc_for_build
+ if echo __ELF__ | $CC_FOR_BUILD -E - 2>/dev/null \
+ | grep -q __ELF__
+ then
+ # Once all utilities can be ECOFF (netbsdecoff) or a.out (netbsdaout).
+ # Return netbsd for either. FIX?
+ os=netbsd
+ else
+ os=netbsdelf
+ fi
+ ;;
+ *)
+ os=netbsd
+ ;;
+ esac
+ # The OS release
+ # Debian GNU/NetBSD machines have a different userland, and
+ # thus, need a distinct triplet. However, they do not need
+ # kernel version information, so it can be replaced with a
+ # suitable tag, in the style of linux-gnu.
+ case "${UNAME_VERSION}" in
+ Debian*)
+ release='-gnu'
+ ;;
+ *)
+ release=`echo ${UNAME_RELEASE}|sed -e 's/[-_].*/\./'`
+ ;;
+ esac
+ # Since CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM:
+ # contains redundant information, the shorter form:
+ # CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM is used.
+ echo "${machine}-${os}${release}"
+ exit ;;
+ *:OpenBSD:*:*)
+ UNAME_MACHINE_ARCH=`arch | sed 's/OpenBSD.//'`
+ echo ${UNAME_MACHINE_ARCH}-unknown-openbsd${UNAME_RELEASE}
+ exit ;;
+ *:ekkoBSD:*:*)
+ echo ${UNAME_MACHINE}-unknown-ekkobsd${UNAME_RELEASE}
+ exit ;;
+ *:SolidBSD:*:*)
+ echo ${UNAME_MACHINE}-unknown-solidbsd${UNAME_RELEASE}
+ exit ;;
+ macppc:MirBSD:*:*)
+ echo powerpc-unknown-mirbsd${UNAME_RELEASE}
+ exit ;;
+ *:MirBSD:*:*)
+ echo ${UNAME_MACHINE}-unknown-mirbsd${UNAME_RELEASE}
+ exit ;;
+ alpha:OSF1:*:*)
+ case $UNAME_RELEASE in
+ *4.0)
+ UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $3}'`
+ ;;
+ *5.*)
+ UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $4}'`
+ ;;
+ esac
+ # According to Compaq, /usr/sbin/psrinfo has been available on
+ # OSF/1 and Tru64 systems produced since 1995. I hope that
+ # covers most systems running today. This code pipes the CPU
+ # types through head -n 1, so we only detect the type of CPU 0.
+ ALPHA_CPU_TYPE=`/usr/sbin/psrinfo -v | sed -n -e 's/^ The alpha \(.*\) processor.*$/\1/p' | head -n 1`
+ case "$ALPHA_CPU_TYPE" in
+ "EV4 (21064)")
+ UNAME_MACHINE="alpha" ;;
+ "EV4.5 (21064)")
+ UNAME_MACHINE="alpha" ;;
+ "LCA4 (21066/21068)")
+ UNAME_MACHINE="alpha" ;;
+ "EV5 (21164)")
+ UNAME_MACHINE="alphaev5" ;;
+ "EV5.6 (21164A)")
+ UNAME_MACHINE="alphaev56" ;;
+ "EV5.6 (21164PC)")
+ UNAME_MACHINE="alphapca56" ;;
+ "EV5.7 (21164PC)")
+ UNAME_MACHINE="alphapca57" ;;
+ "EV6 (21264)")
+ UNAME_MACHINE="alphaev6" ;;
+ "EV6.7 (21264A)")
+ UNAME_MACHINE="alphaev67" ;;
+ "EV6.8CB (21264C)")
+ UNAME_MACHINE="alphaev68" ;;
+ "EV6.8AL (21264B)")
+ UNAME_MACHINE="alphaev68" ;;
+ "EV6.8CX (21264D)")
+ UNAME_MACHINE="alphaev68" ;;
+ "EV6.9A (21264/EV69A)")
+ UNAME_MACHINE="alphaev69" ;;
+ "EV7 (21364)")
+ UNAME_MACHINE="alphaev7" ;;
+ "EV7.9 (21364A)")
+ UNAME_MACHINE="alphaev79" ;;
+ esac
+ # A Pn.n version is a patched version.
+ # A Vn.n version is a released version.
+ # A Tn.n version is a released field test version.
+ # A Xn.n version is an unreleased experimental baselevel.
+ # 1.2 uses "1.2" for uname -r.
+ echo ${UNAME_MACHINE}-dec-osf`echo ${UNAME_RELEASE} | sed -e 's/^[PVTX]//' | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz'`
+ exit ;;
+ Alpha\ *:Windows_NT*:*)
+ # How do we know it's Interix rather than the generic POSIX subsystem?
+ # Should we change UNAME_MACHINE based on the output of uname instead
+ # of the specific Alpha model?
+ echo alpha-pc-interix
+ exit ;;
+ 21064:Windows_NT:50:3)
+ echo alpha-dec-winnt3.5
+ exit ;;
+ Amiga*:UNIX_System_V:4.0:*)
+ echo m68k-unknown-sysv4
+ exit ;;
+ *:[Aa]miga[Oo][Ss]:*:*)
+ echo ${UNAME_MACHINE}-unknown-amigaos
+ exit ;;
+ *:[Mm]orph[Oo][Ss]:*:*)
+ echo ${UNAME_MACHINE}-unknown-morphos
+ exit ;;
+ *:OS/390:*:*)
+ echo i370-ibm-openedition
+ exit ;;
+ *:z/VM:*:*)
+ echo s390-ibm-zvmoe
+ exit ;;
+ *:OS400:*:*)
+ echo powerpc-ibm-os400
+ exit ;;
+ arm:RISC*:1.[012]*:*|arm:riscix:1.[012]*:*)
+ echo arm-acorn-riscix${UNAME_RELEASE}
+ exit ;;
+ arm:riscos:*:*|arm:RISCOS:*:*)
+ echo arm-unknown-riscos
+ exit ;;
+ SR2?01:HI-UX/MPP:*:* | SR8000:HI-UX/MPP:*:*)
+ echo hppa1.1-hitachi-hiuxmpp
+ exit ;;
+ Pyramid*:OSx*:*:* | MIS*:OSx*:*:* | MIS*:SMP_DC-OSx*:*:*)
+ # akee@wpdis03.wpafb.af.mil (Earle F. Ake) contributed MIS and NILE.
+ if test "`(/bin/universe) 2>/dev/null`" = att ; then
+ echo pyramid-pyramid-sysv3
+ else
+ echo pyramid-pyramid-bsd
+ fi
+ exit ;;
+ NILE*:*:*:dcosx)
+ echo pyramid-pyramid-svr4
+ exit ;;
+ DRS?6000:unix:4.0:6*)
+ echo sparc-icl-nx6
+ exit ;;
+ DRS?6000:UNIX_SV:4.2*:7* | DRS?6000:isis:4.2*:7*)
+ case `/usr/bin/uname -p` in
+ sparc) echo sparc-icl-nx7; exit ;;
+ esac ;;
+ s390x:SunOS:*:*)
+ echo ${UNAME_MACHINE}-ibm-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+ exit ;;
+ sun4H:SunOS:5.*:*)
+ echo sparc-hal-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+ exit ;;
+ sun4*:SunOS:5.*:* | tadpole*:SunOS:5.*:*)
+ echo sparc-sun-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+ exit ;;
+ i86pc:AuroraUX:5.*:* | i86xen:AuroraUX:5.*:*)
+ echo i386-pc-auroraux${UNAME_RELEASE}
+ exit ;;
+ i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
+ eval $set_cc_for_build
+ SUN_ARCH="i386"
+ # If there is a compiler, see if it is configured for 64-bit objects.
+ # Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
+ # This test works for both compilers.
+ if [ "$CC_FOR_BUILD" != 'no_compiler_found' ]; then
+ if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
+ (CCOPTS= $CC_FOR_BUILD -E - 2>/dev/null) | \
+ grep IS_64BIT_ARCH >/dev/null
+ then
+ SUN_ARCH="x86_64"
+ fi
+ fi
+ echo ${SUN_ARCH}-pc-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+ exit ;;
+ sun4*:SunOS:6*:*)
+ # According to config.sub, this is the proper way to canonicalize
+ # SunOS6. Hard to guess exactly what SunOS6 will be like, but
+ # it's likely to be more like Solaris than SunOS4.
+ echo sparc-sun-solaris3`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+ exit ;;
+ sun4*:SunOS:*:*)
+ case "`/usr/bin/arch -k`" in
+ Series*|S4*)
+ UNAME_RELEASE=`uname -v`
+ ;;
+ esac
+ # Japanese Language versions have a version number like `4.1.3-JL'.
+ echo sparc-sun-sunos`echo ${UNAME_RELEASE}|sed -e 's/-/_/'`
+ exit ;;
+ sun3*:SunOS:*:*)
+ echo m68k-sun-sunos${UNAME_RELEASE}
+ exit ;;
+ sun*:*:4.2BSD:*)
+ UNAME_RELEASE=`(sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null`
+ test "x${UNAME_RELEASE}" = "x" && UNAME_RELEASE=3
+ case "`/bin/arch`" in
+ sun3)
+ echo m68k-sun-sunos${UNAME_RELEASE}
+ ;;
+ sun4)
+ echo sparc-sun-sunos${UNAME_RELEASE}
+ ;;
+ esac
+ exit ;;
+ aushp:SunOS:*:*)
+ echo sparc-auspex-sunos${UNAME_RELEASE}
+ exit ;;
+ # The situation for MiNT is a little confusing. The machine name
+ # can be virtually everything (everything which is not
+ # "atarist" or "atariste" at least should have a processor
+ # > m68000). The system name ranges from "MiNT" over "FreeMiNT"
+ # to the lowercase version "mint" (or "freemint"). Finally
+ # the system name "TOS" denotes a system which is actually not
+ # MiNT. But MiNT is downward compatible to TOS, so this should
+ # be no problem.
+ atarist[e]:*MiNT:*:* | atarist[e]:*mint:*:* | atarist[e]:*TOS:*:*)
+ echo m68k-atari-mint${UNAME_RELEASE}
+ exit ;;
+ atari*:*MiNT:*:* | atari*:*mint:*:* | atarist[e]:*TOS:*:*)
+ echo m68k-atari-mint${UNAME_RELEASE}
+ exit ;;
+ *falcon*:*MiNT:*:* | *falcon*:*mint:*:* | *falcon*:*TOS:*:*)
+ echo m68k-atari-mint${UNAME_RELEASE}
+ exit ;;
+ milan*:*MiNT:*:* | milan*:*mint:*:* | *milan*:*TOS:*:*)
+ echo m68k-milan-mint${UNAME_RELEASE}
+ exit ;;
+ hades*:*MiNT:*:* | hades*:*mint:*:* | *hades*:*TOS:*:*)
+ echo m68k-hades-mint${UNAME_RELEASE}
+ exit ;;
+ *:*MiNT:*:* | *:*mint:*:* | *:*TOS:*:*)
+ echo m68k-unknown-mint${UNAME_RELEASE}
+ exit ;;
+ m68k:machten:*:*)
+ echo m68k-apple-machten${UNAME_RELEASE}
+ exit ;;
+ powerpc:machten:*:*)
+ echo powerpc-apple-machten${UNAME_RELEASE}
+ exit ;;
+ RISC*:Mach:*:*)
+ echo mips-dec-mach_bsd4.3
+ exit ;;
+ RISC*:ULTRIX:*:*)
+ echo mips-dec-ultrix${UNAME_RELEASE}
+ exit ;;
+ VAX*:ULTRIX*:*:*)
+ echo vax-dec-ultrix${UNAME_RELEASE}
+ exit ;;
+ 2020:CLIX:*:* | 2430:CLIX:*:*)
+ echo clipper-intergraph-clix${UNAME_RELEASE}
+ exit ;;
+ mips:*:*:UMIPS | mips:*:*:RISCos)
+ eval $set_cc_for_build
+ sed 's/^ //' << EOF >$dummy.c
+#ifdef __cplusplus
+#include <stdio.h> /* for printf() prototype */
+ int main (int argc, char *argv[]) {
+#else
+ int main (argc, argv) int argc; char *argv[]; {
+#endif
+ #if defined (host_mips) && defined (MIPSEB)
+ #if defined (SYSTYPE_SYSV)
+ printf ("mips-mips-riscos%ssysv\n", argv[1]); exit (0);
+ #endif
+ #if defined (SYSTYPE_SVR4)
+ printf ("mips-mips-riscos%ssvr4\n", argv[1]); exit (0);
+ #endif
+ #if defined (SYSTYPE_BSD43) || defined(SYSTYPE_BSD)
+ printf ("mips-mips-riscos%sbsd\n", argv[1]); exit (0);
+ #endif
+ #endif
+ exit (-1);
+ }
+EOF
+ $CC_FOR_BUILD -o $dummy $dummy.c &&
+ dummyarg=`echo "${UNAME_RELEASE}" | sed -n 's/\([0-9]*\).*/\1/p'` &&
+ SYSTEM_NAME=`$dummy $dummyarg` &&
+ { echo "$SYSTEM_NAME"; exit; }
+ echo mips-mips-riscos${UNAME_RELEASE}
+ exit ;;
+ Motorola:PowerMAX_OS:*:*)
+ echo powerpc-motorola-powermax
+ exit ;;
+ Motorola:*:4.3:PL8-*)
+ echo powerpc-harris-powermax
+ exit ;;
+ Night_Hawk:*:*:PowerMAX_OS | Synergy:PowerMAX_OS:*:*)
+ echo powerpc-harris-powermax
+ exit ;;
+ Night_Hawk:Power_UNIX:*:*)
+ echo powerpc-harris-powerunix
+ exit ;;
+ m88k:CX/UX:7*:*)
+ echo m88k-harris-cxux7
+ exit ;;
+ m88k:*:4*:R4*)
+ echo m88k-motorola-sysv4
+ exit ;;
+ m88k:*:3*:R3*)
+ echo m88k-motorola-sysv3
+ exit ;;
+ AViiON:dgux:*:*)
+ # DG/UX returns AViiON for all architectures
+ UNAME_PROCESSOR=`/usr/bin/uname -p`
+ if [ $UNAME_PROCESSOR = mc88100 ] || [ $UNAME_PROCESSOR = mc88110 ]
+ then
+ if [ ${TARGET_BINARY_INTERFACE}x = m88kdguxelfx ] || \
+ [ ${TARGET_BINARY_INTERFACE}x = x ]
+ then
+ echo m88k-dg-dgux${UNAME_RELEASE}
+ else
+ echo m88k-dg-dguxbcs${UNAME_RELEASE}
+ fi
+ else
+ echo i586-dg-dgux${UNAME_RELEASE}
+ fi
+ exit ;;
+ M88*:DolphinOS:*:*) # DolphinOS (SVR3)
+ echo m88k-dolphin-sysv3
+ exit ;;
+ M88*:*:R3*:*)
+ # Delta 88k system running SVR3
+ echo m88k-motorola-sysv3
+ exit ;;
+ XD88*:*:*:*) # Tektronix XD88 system running UTekV (SVR3)
+ echo m88k-tektronix-sysv3
+ exit ;;
+ Tek43[0-9][0-9]:UTek:*:*) # Tektronix 4300 system running UTek (BSD)
+ echo m68k-tektronix-bsd
+ exit ;;
+ *:IRIX*:*:*)
+ echo mips-sgi-irix`echo ${UNAME_RELEASE}|sed -e 's/-/_/g'`
+ exit ;;
+ ????????:AIX?:[12].1:2) # AIX 2.2.1 or AIX 2.1.1 is RT/PC AIX.
+ echo romp-ibm-aix # uname -m gives an 8 hex-code CPU id
+ exit ;; # Note that: echo "'`uname -s`'" gives 'AIX '
+ i*86:AIX:*:*)
+ echo i386-ibm-aix
+ exit ;;
+ ia64:AIX:*:*)
+ if [ -x /usr/bin/oslevel ] ; then
+ IBM_REV=`/usr/bin/oslevel`
+ else
+ IBM_REV=${UNAME_VERSION}.${UNAME_RELEASE}
+ fi
+ echo ${UNAME_MACHINE}-ibm-aix${IBM_REV}
+ exit ;;
+ *:AIX:2:3)
+ if grep bos325 /usr/include/stdio.h >/dev/null 2>&1; then
+ eval $set_cc_for_build
+ sed 's/^ //' << EOF >$dummy.c
+ #include <sys/systemcfg.h>
+
+ main()
+ {
+ if (!__power_pc())
+ exit(1);
+ puts("powerpc-ibm-aix3.2.5");
+ exit(0);
+ }
+EOF
+ if $CC_FOR_BUILD -o $dummy $dummy.c && SYSTEM_NAME=`$dummy`
+ then
+ echo "$SYSTEM_NAME"
+ else
+ echo rs6000-ibm-aix3.2.5
+ fi
+ elif grep bos324 /usr/include/stdio.h >/dev/null 2>&1; then
+ echo rs6000-ibm-aix3.2.4
+ else
+ echo rs6000-ibm-aix3.2
+ fi
+ exit ;;
+ *:AIX:*:[456])
+ IBM_CPU_ID=`/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }'`
+ if /usr/sbin/lsattr -El ${IBM_CPU_ID} | grep ' POWER' >/dev/null 2>&1; then
+ IBM_ARCH=rs6000
+ else
+ IBM_ARCH=powerpc
+ fi
+ if [ -x /usr/bin/oslevel ] ; then
+ IBM_REV=`/usr/bin/oslevel`
+ else
+ IBM_REV=${UNAME_VERSION}.${UNAME_RELEASE}
+ fi
+ echo ${IBM_ARCH}-ibm-aix${IBM_REV}
+ exit ;;
+ *:AIX:*:*)
+ echo rs6000-ibm-aix
+ exit ;;
+ ibmrt:4.4BSD:*|romp-ibm:BSD:*)
+ echo romp-ibm-bsd4.4
+ exit ;;
+ ibmrt:*BSD:*|romp-ibm:BSD:*) # covers RT/PC BSD and
+ echo romp-ibm-bsd${UNAME_RELEASE} # 4.3 with uname added to
+ exit ;; # report: romp-ibm BSD 4.3
+ *:BOSX:*:*)
+ echo rs6000-bull-bosx
+ exit ;;
+ DPX/2?00:B.O.S.:*:*)
+ echo m68k-bull-sysv3
+ exit ;;
+ 9000/[34]??:4.3bsd:1.*:*)
+ echo m68k-hp-bsd
+ exit ;;
+ hp300:4.4BSD:*:* | 9000/[34]??:4.3bsd:2.*:*)
+ echo m68k-hp-bsd4.4
+ exit ;;
+ 9000/[34678]??:HP-UX:*:*)
+ HPUX_REV=`echo ${UNAME_RELEASE}|sed -e 's/[^.]*.[0B]*//'`
+ case "${UNAME_MACHINE}" in
+ 9000/31? ) HP_ARCH=m68000 ;;
+ 9000/[34]?? ) HP_ARCH=m68k ;;
+ 9000/[678][0-9][0-9])
+ if [ -x /usr/bin/getconf ]; then
+ sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
+ sc_kernel_bits=`/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null`
+ case "${sc_cpu_version}" in
+ 523) HP_ARCH="hppa1.0" ;; # CPU_PA_RISC1_0
+ 528) HP_ARCH="hppa1.1" ;; # CPU_PA_RISC1_1
+ 532) # CPU_PA_RISC2_0
+ case "${sc_kernel_bits}" in
+ 32) HP_ARCH="hppa2.0n" ;;
+ 64) HP_ARCH="hppa2.0w" ;;
+ '') HP_ARCH="hppa2.0" ;; # HP-UX 10.20
+ esac ;;
+ esac
+ fi
+ if [ "${HP_ARCH}" = "" ]; then
+ eval $set_cc_for_build
+ sed 's/^ //' << EOF >$dummy.c
+
+ #define _HPUX_SOURCE
+ #include <stdlib.h>
+ #include <unistd.h>
+
+ int main ()
+ {
+ #if defined(_SC_KERNEL_BITS)
+ long bits = sysconf(_SC_KERNEL_BITS);
+ #endif
+ long cpu = sysconf (_SC_CPU_VERSION);
+
+ switch (cpu)
+ {
+ case CPU_PA_RISC1_0: puts ("hppa1.0"); break;
+ case CPU_PA_RISC1_1: puts ("hppa1.1"); break;
+ case CPU_PA_RISC2_0:
+ #if defined(_SC_KERNEL_BITS)
+ switch (bits)
+ {
+ case 64: puts ("hppa2.0w"); break;
+ case 32: puts ("hppa2.0n"); break;
+ default: puts ("hppa2.0"); break;
+ } break;
+ #else /* !defined(_SC_KERNEL_BITS) */
+ puts ("hppa2.0"); break;
+ #endif
+ default: puts ("hppa1.0"); break;
+ }
+ exit (0);
+ }
+EOF
+ (CCOPTS= $CC_FOR_BUILD -o $dummy $dummy.c 2>/dev/null) && HP_ARCH=`$dummy`
+ test -z "$HP_ARCH" && HP_ARCH=hppa
+ fi ;;
+ esac
+ if [ ${HP_ARCH} = "hppa2.0w" ]
+ then
+ eval $set_cc_for_build
+
+ # hppa2.0w-hp-hpux* has a 64-bit kernel and a compiler generating
+ # 32-bit code. hppa64-hp-hpux* has the same kernel and a compiler
+ # generating 64-bit code. GNU and HP use different nomenclature:
+ #
+ # $ CC_FOR_BUILD=cc ./config.guess
+ # => hppa2.0w-hp-hpux11.23
+ # $ CC_FOR_BUILD="cc +DA2.0w" ./config.guess
+ # => hppa64-hp-hpux11.23
+
+ if echo __LP64__ | (CCOPTS= $CC_FOR_BUILD -E - 2>/dev/null) |
+ grep -q __LP64__
+ then
+ HP_ARCH="hppa2.0w"
+ else
+ HP_ARCH="hppa64"
+ fi
+ fi
+ echo ${HP_ARCH}-hp-hpux${HPUX_REV}
+ exit ;;
+ ia64:HP-UX:*:*)
+ HPUX_REV=`echo ${UNAME_RELEASE}|sed -e 's/[^.]*.[0B]*//'`
+ echo ia64-hp-hpux${HPUX_REV}
+ exit ;;
+ 3050*:HI-UX:*:*)
+ eval $set_cc_for_build
+ sed 's/^ //' << EOF >$dummy.c
+ #include <unistd.h>
+ int
+ main ()
+ {
+ long cpu = sysconf (_SC_CPU_VERSION);
+ /* The order matters, because CPU_IS_HP_MC68K erroneously returns
+ true for CPU_PA_RISC1_0. CPU_IS_PA_RISC returns correct
+ results, however. */
+ if (CPU_IS_PA_RISC (cpu))
+ {
+ switch (cpu)
+ {
+ case CPU_PA_RISC1_0: puts ("hppa1.0-hitachi-hiuxwe2"); break;
+ case CPU_PA_RISC1_1: puts ("hppa1.1-hitachi-hiuxwe2"); break;
+ case CPU_PA_RISC2_0: puts ("hppa2.0-hitachi-hiuxwe2"); break;
+ default: puts ("hppa-hitachi-hiuxwe2"); break;
+ }
+ }
+ else if (CPU_IS_HP_MC68K (cpu))
+ puts ("m68k-hitachi-hiuxwe2");
+ else puts ("unknown-hitachi-hiuxwe2");
+ exit (0);
+ }
+EOF
+ $CC_FOR_BUILD -o $dummy $dummy.c && SYSTEM_NAME=`$dummy` &&
+ { echo "$SYSTEM_NAME"; exit; }
+ echo unknown-hitachi-hiuxwe2
+ exit ;;
+ 9000/7??:4.3bsd:*:* | 9000/8?[79]:4.3bsd:*:* )
+ echo hppa1.1-hp-bsd
+ exit ;;
+ 9000/8??:4.3bsd:*:*)
+ echo hppa1.0-hp-bsd
+ exit ;;
+ *9??*:MPE/iX:*:* | *3000*:MPE/iX:*:*)
+ echo hppa1.0-hp-mpeix
+ exit ;;
+ hp7??:OSF1:*:* | hp8?[79]:OSF1:*:* )
+ echo hppa1.1-hp-osf
+ exit ;;
+ hp8??:OSF1:*:*)
+ echo hppa1.0-hp-osf
+ exit ;;
+ i*86:OSF1:*:*)
+ if [ -x /usr/sbin/sysversion ] ; then
+ echo ${UNAME_MACHINE}-unknown-osf1mk
+ else
+ echo ${UNAME_MACHINE}-unknown-osf1
+ fi
+ exit ;;
+ parisc*:Lites*:*:*)
+ echo hppa1.1-hp-lites
+ exit ;;
+ C1*:ConvexOS:*:* | convex:ConvexOS:C1*:*)
+ echo c1-convex-bsd
+ exit ;;
+ C2*:ConvexOS:*:* | convex:ConvexOS:C2*:*)
+ if getsysinfo -f scalar_acc
+ then echo c32-convex-bsd
+ else echo c2-convex-bsd
+ fi
+ exit ;;
+ C34*:ConvexOS:*:* | convex:ConvexOS:C34*:*)
+ echo c34-convex-bsd
+ exit ;;
+ C38*:ConvexOS:*:* | convex:ConvexOS:C38*:*)
+ echo c38-convex-bsd
+ exit ;;
+ C4*:ConvexOS:*:* | convex:ConvexOS:C4*:*)
+ echo c4-convex-bsd
+ exit ;;
+ CRAY*Y-MP:*:*:*)
+ echo ymp-cray-unicos${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
+ exit ;;
+ CRAY*[A-Z]90:*:*:*)
+ echo ${UNAME_MACHINE}-cray-unicos${UNAME_RELEASE} \
+ | sed -e 's/CRAY.*\([A-Z]90\)/\1/' \
+ -e y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/ \
+ -e 's/\.[^.]*$/.X/'
+ exit ;;
+ CRAY*TS:*:*:*)
+ echo t90-cray-unicos${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
+ exit ;;
+ CRAY*T3E:*:*:*)
+ echo alphaev5-cray-unicosmk${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
+ exit ;;
+ CRAY*SV1:*:*:*)
+ echo sv1-cray-unicos${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
+ exit ;;
+ *:UNICOS/mp:*:*)
+ echo craynv-cray-unicosmp${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
+ exit ;;
+ F30[01]:UNIX_System_V:*:* | F700:UNIX_System_V:*:*)
+ FUJITSU_PROC=`uname -m | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz'`
+ FUJITSU_SYS=`uname -p | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz' | sed -e 's/\///'`
+ FUJITSU_REL=`echo ${UNAME_RELEASE} | sed -e 's/ /_/'`
+ echo "${FUJITSU_PROC}-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
+ exit ;;
+ 5000:UNIX_System_V:4.*:*)
+ FUJITSU_SYS=`uname -p | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz' | sed -e 's/\///'`
+ FUJITSU_REL=`echo ${UNAME_RELEASE} | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz' | sed -e 's/ /_/'`
+ echo "sparc-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
+ exit ;;
+ i*86:BSD/386:*:* | i*86:BSD/OS:*:* | *:Ascend\ Embedded/OS:*:*)
+ echo ${UNAME_MACHINE}-pc-bsdi${UNAME_RELEASE}
+ exit ;;
+ sparc*:BSD/OS:*:*)
+ echo sparc-unknown-bsdi${UNAME_RELEASE}
+ exit ;;
+ *:BSD/OS:*:*)
+ echo ${UNAME_MACHINE}-unknown-bsdi${UNAME_RELEASE}
+ exit ;;
+ *:FreeBSD:*:*)
+ case ${UNAME_MACHINE} in
+ pc98)
+ echo i386-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'` ;;
+ amd64)
+ echo x86_64-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'` ;;
+ *)
+ echo ${UNAME_MACHINE}-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'` ;;
+ esac
+ exit ;;
+ i*:CYGWIN*:*)
+ echo ${UNAME_MACHINE}-pc-cygwin
+ exit ;;
+ *:MINGW*:*)
+ echo ${UNAME_MACHINE}-pc-mingw32
+ exit ;;
+ i*:windows32*:*)
+ # uname -m includes "-pc" on this system.
+ echo ${UNAME_MACHINE}-mingw32
+ exit ;;
+ i*:PW*:*)
+ echo ${UNAME_MACHINE}-pc-pw32
+ exit ;;
+ *:Interix*:*)
+ case ${UNAME_MACHINE} in
+ x86)
+ echo i586-pc-interix${UNAME_RELEASE}
+ exit ;;
+ authenticamd | genuineintel | EM64T)
+ echo x86_64-unknown-interix${UNAME_RELEASE}
+ exit ;;
+ IA64)
+ echo ia64-unknown-interix${UNAME_RELEASE}
+ exit ;;
+ esac ;;
+ [345]86:Windows_95:* | [345]86:Windows_98:* | [345]86:Windows_NT:*)
+ echo i${UNAME_MACHINE}-pc-mks
+ exit ;;
+ 8664:Windows_NT:*)
+ echo x86_64-pc-mks
+ exit ;;
+ i*:Windows_NT*:* | Pentium*:Windows_NT*:*)
+ # How do we know it's Interix rather than the generic POSIX subsystem?
+ # It also conflicts with pre-2.0 versions of AT&T UWIN. Should we
+ # UNAME_MACHINE based on the output of uname instead of i386?
+ echo i586-pc-interix
+ exit ;;
+ i*:UWIN*:*)
+ echo ${UNAME_MACHINE}-pc-uwin
+ exit ;;
+ amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
+ echo x86_64-unknown-cygwin
+ exit ;;
+ p*:CYGWIN*:*)
+ echo powerpcle-unknown-cygwin
+ exit ;;
+ prep*:SunOS:5.*:*)
+ echo powerpcle-unknown-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+ exit ;;
+ *:GNU:*:*)
+ # the GNU system
+ echo `echo ${UNAME_MACHINE}|sed -e 's,[-/].*$,,'`-unknown-gnu`echo ${UNAME_RELEASE}|sed -e 's,/.*$,,'`
+ exit ;;
+ *:GNU/*:*:*)
+ # other systems with GNU libc and userland
+ echo ${UNAME_MACHINE}-unknown-`echo ${UNAME_SYSTEM} | sed 's,^[^/]*/,,' | tr '[A-Z]' '[a-z]'``echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`-gnu
+ exit ;;
+ i*86:Minix:*:*)
+ echo ${UNAME_MACHINE}-pc-minix
+ exit ;;
+ alpha:Linux:*:*)
+ case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
+ EV5) UNAME_MACHINE=alphaev5 ;;
+ EV56) UNAME_MACHINE=alphaev56 ;;
+ PCA56) UNAME_MACHINE=alphapca56 ;;
+ PCA57) UNAME_MACHINE=alphapca56 ;;
+ EV6) UNAME_MACHINE=alphaev6 ;;
+ EV67) UNAME_MACHINE=alphaev67 ;;
+ EV68*) UNAME_MACHINE=alphaev68 ;;
+ esac
+ objdump --private-headers /bin/sh | grep -q ld.so.1
+ if test "$?" = 0 ; then LIBC="libc1" ; else LIBC="" ; fi
+ echo ${UNAME_MACHINE}-unknown-linux-gnu${LIBC}
+ exit ;;
+ arm*:Linux:*:*)
+ eval $set_cc_for_build
+ if echo __ARM_EABI__ | $CC_FOR_BUILD -E - 2>/dev/null \
+ | grep -q __ARM_EABI__
+ then
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ else
+ echo ${UNAME_MACHINE}-unknown-linux-gnueabi
+ fi
+ exit ;;
+ avr32*:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ cris:Linux:*:*)
+ echo cris-axis-linux-gnu
+ exit ;;
+ crisv32:Linux:*:*)
+ echo crisv32-axis-linux-gnu
+ exit ;;
+ frv:Linux:*:*)
+ echo frv-unknown-linux-gnu
+ exit ;;
+ i*86:Linux:*:*)
+ LIBC=gnu
+ eval $set_cc_for_build
+ sed 's/^ //' << EOF >$dummy.c
+ #ifdef __dietlibc__
+ LIBC=dietlibc
+ #endif
+EOF
+ eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^LIBC'`
+ echo "${UNAME_MACHINE}-pc-linux-${LIBC}"
+ exit ;;
+ ia64:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ m32r*:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ m68*:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ mips:Linux:*:* | mips64:Linux:*:*)
+ eval $set_cc_for_build
+ sed 's/^ //' << EOF >$dummy.c
+ #undef CPU
+ #undef ${UNAME_MACHINE}
+ #undef ${UNAME_MACHINE}el
+ #if defined(__MIPSEL__) || defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL)
+ CPU=${UNAME_MACHINE}el
+ #else
+ #if defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB)
+ CPU=${UNAME_MACHINE}
+ #else
+ CPU=
+ #endif
+ #endif
+EOF
+ eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^CPU'`
+ test x"${CPU}" != x && { echo "${CPU}-unknown-linux-gnu"; exit; }
+ ;;
+ or32:Linux:*:*)
+ echo or32-unknown-linux-gnu
+ exit ;;
+ padre:Linux:*:*)
+ echo sparc-unknown-linux-gnu
+ exit ;;
+ parisc64:Linux:*:* | hppa64:Linux:*:*)
+ echo hppa64-unknown-linux-gnu
+ exit ;;
+ parisc:Linux:*:* | hppa:Linux:*:*)
+ # Look for CPU level
+ case `grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2` in
+ PA7*) echo hppa1.1-unknown-linux-gnu ;;
+ PA8*) echo hppa2.0-unknown-linux-gnu ;;
+ *) echo hppa-unknown-linux-gnu ;;
+ esac
+ exit ;;
+ ppc64:Linux:*:*)
+ echo powerpc64-unknown-linux-gnu
+ exit ;;
+ ppc:Linux:*:*)
+ echo powerpc-unknown-linux-gnu
+ exit ;;
+ s390:Linux:*:* | s390x:Linux:*:*)
+ echo ${UNAME_MACHINE}-ibm-linux
+ exit ;;
+ sh64*:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ sh*:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ sparc:Linux:*:* | sparc64:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ vax:Linux:*:*)
+ echo ${UNAME_MACHINE}-dec-linux-gnu
+ exit ;;
+ x86_64:Linux:*:*)
+ echo x86_64-unknown-linux-gnu
+ exit ;;
+ xtensa*:Linux:*:*)
+ echo ${UNAME_MACHINE}-unknown-linux-gnu
+ exit ;;
+ i*86:DYNIX/ptx:4*:*)
+ # ptx 4.0 does uname -s correctly, with DYNIX/ptx in there.
+ # earlier versions are messed up and put the nodename in both
+ # sysname and nodename.
+ echo i386-sequent-sysv4
+ exit ;;
+ i*86:UNIX_SV:4.2MP:2.*)
+ # Unixware is an offshoot of SVR4, but it has its own version
+ # number series starting with 2...
+ # I am not positive that other SVR4 systems won't match this,
+ # I just have to hope. -- rms.
+ # Use sysv4.2uw... so that sysv4* matches it.
+ echo ${UNAME_MACHINE}-pc-sysv4.2uw${UNAME_VERSION}
+ exit ;;
+ i*86:OS/2:*:*)
+ # If we were able to find `uname', then EMX Unix compatibility
+ # is probably installed.
+ echo ${UNAME_MACHINE}-pc-os2-emx
+ exit ;;
+ i*86:XTS-300:*:STOP)
+ echo ${UNAME_MACHINE}-unknown-stop
+ exit ;;
+ i*86:atheos:*:*)
+ echo ${UNAME_MACHINE}-unknown-atheos
+ exit ;;
+ i*86:syllable:*:*)
+ echo ${UNAME_MACHINE}-pc-syllable
+ exit ;;
+ i*86:LynxOS:2.*:* | i*86:LynxOS:3.[01]*:* | i*86:LynxOS:4.[02]*:*)
+ echo i386-unknown-lynxos${UNAME_RELEASE}
+ exit ;;
+ i*86:*DOS:*:*)
+ echo ${UNAME_MACHINE}-pc-msdosdjgpp
+ exit ;;
+ i*86:*:4.*:* | i*86:SYSTEM_V:4.*:*)
+ UNAME_REL=`echo ${UNAME_RELEASE} | sed 's/\/MP$//'`
+ if grep Novell /usr/include/link.h >/dev/null 2>/dev/null; then
+ echo ${UNAME_MACHINE}-univel-sysv${UNAME_REL}
+ else
+ echo ${UNAME_MACHINE}-pc-sysv${UNAME_REL}
+ fi
+ exit ;;
+ i*86:*:5:[678]*)
+ # UnixWare 7.x, OpenUNIX and OpenServer 6.
+ case `/bin/uname -X | grep "^Machine"` in
+ *486*) UNAME_MACHINE=i486 ;;
+ *Pentium) UNAME_MACHINE=i586 ;;
+ *Pent*|*Celeron) UNAME_MACHINE=i686 ;;
+ esac
+ echo ${UNAME_MACHINE}-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}${UNAME_VERSION}
+ exit ;;
+ i*86:*:3.2:*)
+ if test -f /usr/options/cb.name; then
+ UNAME_REL=`sed -n 's/.*Version //p' </usr/options/cb.name`
+ echo ${UNAME_MACHINE}-pc-isc$UNAME_REL
+ elif /bin/uname -X 2>/dev/null >/dev/null ; then
+ UNAME_REL=`(/bin/uname -X|grep Release|sed -e 's/.*= //')`
+ (/bin/uname -X|grep i80486 >/dev/null) && UNAME_MACHINE=i486
+ (/bin/uname -X|grep '^Machine.*Pentium' >/dev/null) \
+ && UNAME_MACHINE=i586
+ (/bin/uname -X|grep '^Machine.*Pent *II' >/dev/null) \
+ && UNAME_MACHINE=i686
+ (/bin/uname -X|grep '^Machine.*Pentium Pro' >/dev/null) \
+ && UNAME_MACHINE=i686
+ echo ${UNAME_MACHINE}-pc-sco$UNAME_REL
+ else
+ echo ${UNAME_MACHINE}-pc-sysv32
+ fi
+ exit ;;
+ pc:*:*:*)
+ # Left here for compatibility:
+ # uname -m prints for DJGPP always 'pc', but it prints nothing about
+ # the processor, so we play safe by assuming i586.
+ # Note: whatever this is, it MUST be the same as what config.sub
+ # prints for the "djgpp" host, or else GDB configury will decide that
+ # this is a cross-build.
+ echo i586-pc-msdosdjgpp
+ exit ;;
+ Intel:Mach:3*:*)
+ echo i386-pc-mach3
+ exit ;;
+ paragon:*:*:*)
+ echo i860-intel-osf1
+ exit ;;
+ i860:*:4.*:*) # i860-SVR4
+ if grep Stardent /usr/include/sys/uadmin.h >/dev/null 2>&1 ; then
+ echo i860-stardent-sysv${UNAME_RELEASE} # Stardent Vistra i860-SVR4
+ else # Add other i860-SVR4 vendors below as they are discovered.
+ echo i860-unknown-sysv${UNAME_RELEASE} # Unknown i860-SVR4
+ fi
+ exit ;;
+ mini*:CTIX:SYS*5:*)
+ # "miniframe"
+ echo m68010-convergent-sysv
+ exit ;;
+ mc68k:UNIX:SYSTEM5:3.51m)
+ echo m68k-convergent-sysv
+ exit ;;
+ M680?0:D-NIX:5.3:*)
+ echo m68k-diab-dnix
+ exit ;;
+ M68*:*:R3V[5678]*:*)
+ test -r /sysV68 && { echo 'm68k-motorola-sysv'; exit; } ;;
+ 3[345]??:*:4.0:3.0 | 3[34]??A:*:4.0:3.0 | 3[34]??,*:*:4.0:3.0 | 3[34]??/*:*:4.0:3.0 | 4400:*:4.0:3.0 | 4850:*:4.0:3.0 | SKA40:*:4.0:3.0 | SDS2:*:4.0:3.0 | SHG2:*:4.0:3.0 | S7501*:*:4.0:3.0)
+ OS_REL=''
+ test -r /etc/.relid \
+ && OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+ /bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+ && { echo i486-ncr-sysv4.3${OS_REL}; exit; }
+ /bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
+ && { echo i586-ncr-sysv4.3${OS_REL}; exit; } ;;
+ 3[34]??:*:4.0:* | 3[34]??,*:*:4.0:*)
+ /bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+ && { echo i486-ncr-sysv4; exit; } ;;
+ NCR*:*:4.2:* | MPRAS*:*:4.2:*)
+ OS_REL='.3'
+ test -r /etc/.relid \
+ && OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+ /bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+ && { echo i486-ncr-sysv4.3${OS_REL}; exit; }
+ /bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
+ && { echo i586-ncr-sysv4.3${OS_REL}; exit; }
+ /bin/uname -p 2>/dev/null | /bin/grep pteron >/dev/null \
+ && { echo i586-ncr-sysv4.3${OS_REL}; exit; } ;;
+ m68*:LynxOS:2.*:* | m68*:LynxOS:3.0*:*)
+ echo m68k-unknown-lynxos${UNAME_RELEASE}
+ exit ;;
+ mc68030:UNIX_System_V:4.*:*)
+ echo m68k-atari-sysv4
+ exit ;;
+ TSUNAMI:LynxOS:2.*:*)
+ echo sparc-unknown-lynxos${UNAME_RELEASE}
+ exit ;;
+ rs6000:LynxOS:2.*:*)
+ echo rs6000-unknown-lynxos${UNAME_RELEASE}
+ exit ;;
+ PowerPC:LynxOS:2.*:* | PowerPC:LynxOS:3.[01]*:* | PowerPC:LynxOS:4.[02]*:*)
+ echo powerpc-unknown-lynxos${UNAME_RELEASE}
+ exit ;;
+ SM[BE]S:UNIX_SV:*:*)
+ echo mips-dde-sysv${UNAME_RELEASE}
+ exit ;;
+ RM*:ReliantUNIX-*:*:*)
+ echo mips-sni-sysv4
+ exit ;;
+ RM*:SINIX-*:*:*)
+ echo mips-sni-sysv4
+ exit ;;
+ *:SINIX-*:*:*)
+ if uname -p 2>/dev/null >/dev/null ; then
+ UNAME_MACHINE=`(uname -p) 2>/dev/null`
+ echo ${UNAME_MACHINE}-sni-sysv4
+ else
+ echo ns32k-sni-sysv
+ fi
+ exit ;;
+ PENTIUM:*:4.0*:*) # Unisys `ClearPath HMP IX 4000' SVR4/MP effort
+ # says <Richard.M.Bartel@ccMail.Census.GOV>
+ echo i586-unisys-sysv4
+ exit ;;
+ *:UNIX_System_V:4*:FTX*)
+ # From Gerald Hewes <hewes@openmarket.com>.
+ # How about differentiating between stratus architectures? -djm
+ echo hppa1.1-stratus-sysv4
+ exit ;;
+ *:*:*:FTX*)
+ # From seanf@swdc.stratus.com.
+ echo i860-stratus-sysv4
+ exit ;;
+ i*86:VOS:*:*)
+ # From Paul.Green@stratus.com.
+ echo ${UNAME_MACHINE}-stratus-vos
+ exit ;;
+ *:VOS:*:*)
+ # From Paul.Green@stratus.com.
+ echo hppa1.1-stratus-vos
+ exit ;;
+ mc68*:A/UX:*:*)
+ echo m68k-apple-aux${UNAME_RELEASE}
+ exit ;;
+ news*:NEWS-OS:6*:*)
+ echo mips-sony-newsos6
+ exit ;;
+ R[34]000:*System_V*:*:* | R4000:UNIX_SYSV:*:* | R*000:UNIX_SV:*:*)
+ if [ -d /usr/nec ]; then
+ echo mips-nec-sysv${UNAME_RELEASE}
+ else
+ echo mips-unknown-sysv${UNAME_RELEASE}
+ fi
+ exit ;;
+ BeBox:BeOS:*:*) # BeOS running on hardware made by Be, PPC only.
+ echo powerpc-be-beos
+ exit ;;
+ BeMac:BeOS:*:*) # BeOS running on Mac or Mac clone, PPC only.
+ echo powerpc-apple-beos
+ exit ;;
+ BePC:BeOS:*:*) # BeOS running on Intel PC compatible.
+ echo i586-pc-beos
+ exit ;;
+ BePC:Haiku:*:*) # Haiku running on Intel PC compatible.
+ echo i586-pc-haiku
+ exit ;;
+ SX-4:SUPER-UX:*:*)
+ echo sx4-nec-superux${UNAME_RELEASE}
+ exit ;;
+ SX-5:SUPER-UX:*:*)
+ echo sx5-nec-superux${UNAME_RELEASE}
+ exit ;;
+ SX-6:SUPER-UX:*:*)
+ echo sx6-nec-superux${UNAME_RELEASE}
+ exit ;;
+ SX-7:SUPER-UX:*:*)
+ echo sx7-nec-superux${UNAME_RELEASE}
+ exit ;;
+ SX-8:SUPER-UX:*:*)
+ echo sx8-nec-superux${UNAME_RELEASE}
+ exit ;;
+ SX-8R:SUPER-UX:*:*)
+ echo sx8r-nec-superux${UNAME_RELEASE}
+ exit ;;
+ Power*:Rhapsody:*:*)
+ echo powerpc-apple-rhapsody${UNAME_RELEASE}
+ exit ;;
+ *:Rhapsody:*:*)
+ echo ${UNAME_MACHINE}-apple-rhapsody${UNAME_RELEASE}
+ exit ;;
+ *:Darwin:*:*)
+ UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
+ case $UNAME_PROCESSOR in
+ i386)
+ eval $set_cc_for_build
+ if [ "$CC_FOR_BUILD" != 'no_compiler_found' ]; then
+ if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
+ (CCOPTS= $CC_FOR_BUILD -E - 2>/dev/null) | \
+ grep IS_64BIT_ARCH >/dev/null
+ then
+ UNAME_PROCESSOR="x86_64"
+ fi
+ fi ;;
+ unknown) UNAME_PROCESSOR=powerpc ;;
+ esac
+ echo ${UNAME_PROCESSOR}-apple-darwin${UNAME_RELEASE}
+ exit ;;
+ *:procnto*:*:* | *:QNX:[0123456789]*:*)
+ UNAME_PROCESSOR=`uname -p`
+ if test "$UNAME_PROCESSOR" = "x86"; then
+ UNAME_PROCESSOR=i386
+ UNAME_MACHINE=pc
+ fi
+ echo ${UNAME_PROCESSOR}-${UNAME_MACHINE}-nto-qnx${UNAME_RELEASE}
+ exit ;;
+ *:QNX:*:4*)
+ echo i386-pc-qnx
+ exit ;;
+ NSE-?:NONSTOP_KERNEL:*:*)
+ echo nse-tandem-nsk${UNAME_RELEASE}
+ exit ;;
+ NSR-?:NONSTOP_KERNEL:*:*)
+ echo nsr-tandem-nsk${UNAME_RELEASE}
+ exit ;;
+ *:NonStop-UX:*:*)
+ echo mips-compaq-nonstopux
+ exit ;;
+ BS2000:POSIX*:*:*)
+ echo bs2000-siemens-sysv
+ exit ;;
+ DS/*:UNIX_System_V:*:*)
+ echo ${UNAME_MACHINE}-${UNAME_SYSTEM}-${UNAME_RELEASE}
+ exit ;;
+ *:Plan9:*:*)
+ # "uname -m" is not consistent, so use $cputype instead. 386
+ # is converted to i386 for consistency with other x86
+ # operating systems.
+ if test "$cputype" = "386"; then
+ UNAME_MACHINE=i386
+ else
+ UNAME_MACHINE="$cputype"
+ fi
+ echo ${UNAME_MACHINE}-unknown-plan9
+ exit ;;
+ *:TOPS-10:*:*)
+ echo pdp10-unknown-tops10
+ exit ;;
+ *:TENEX:*:*)
+ echo pdp10-unknown-tenex
+ exit ;;
+ KS10:TOPS-20:*:* | KL10:TOPS-20:*:* | TYPE4:TOPS-20:*:*)
+ echo pdp10-dec-tops20
+ exit ;;
+ XKL-1:TOPS-20:*:* | TYPE5:TOPS-20:*:*)
+ echo pdp10-xkl-tops20
+ exit ;;
+ *:TOPS-20:*:*)
+ echo pdp10-unknown-tops20
+ exit ;;
+ *:ITS:*:*)
+ echo pdp10-unknown-its
+ exit ;;
+ SEI:*:*:SEIUX)
+ echo mips-sei-seiux${UNAME_RELEASE}
+ exit ;;
+ *:DragonFly:*:*)
+ echo ${UNAME_MACHINE}-unknown-dragonfly`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`
+ exit ;;
+ *:*VMS:*:*)
+ UNAME_MACHINE=`(uname -p) 2>/dev/null`
+ case "${UNAME_MACHINE}" in
+ A*) echo alpha-dec-vms ; exit ;;
+ I*) echo ia64-dec-vms ; exit ;;
+ V*) echo vax-dec-vms ; exit ;;
+ esac ;;
+ *:XENIX:*:SysV)
+ echo i386-pc-xenix
+ exit ;;
+ i*86:skyos:*:*)
+ echo ${UNAME_MACHINE}-pc-skyos`echo ${UNAME_RELEASE}` | sed -e 's/ .*$//'
+ exit ;;
+ i*86:rdos:*:*)
+ echo ${UNAME_MACHINE}-pc-rdos
+ exit ;;
+ i*86:AROS:*:*)
+ echo ${UNAME_MACHINE}-pc-aros
+ exit ;;
+esac
+
+#echo '(No uname command or uname output not recognized.)' 1>&2
+#echo "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" 1>&2
+
+eval $set_cc_for_build
+cat >$dummy.c <<EOF
+#ifdef _SEQUENT_
+# include <sys/types.h>
+# include <sys/utsname.h>
+#endif
+main ()
+{
+#if defined (sony)
+#if defined (MIPSEB)
+ /* BFD wants "bsd" instead of "newsos". Perhaps BFD should be changed,
+ I don't know.... */
+ printf ("mips-sony-bsd\n"); exit (0);
+#else
+#include <sys/param.h>
+ printf ("m68k-sony-newsos%s\n",
+#ifdef NEWSOS4
+ "4"
+#else
+ ""
+#endif
+ ); exit (0);
+#endif
+#endif
+
+#if defined (__arm) && defined (__acorn) && defined (__unix)
+ printf ("arm-acorn-riscix\n"); exit (0);
+#endif
+
+#if defined (hp300) && !defined (hpux)
+ printf ("m68k-hp-bsd\n"); exit (0);
+#endif
+
+#if defined (NeXT)
+#if !defined (__ARCHITECTURE__)
+#define __ARCHITECTURE__ "m68k"
+#endif
+ int version;
+ version=`(hostinfo | sed -n 's/.*NeXT Mach \([0-9]*\).*/\1/p') 2>/dev/null`;
+ if (version < 4)
+ printf ("%s-next-nextstep%d\n", __ARCHITECTURE__, version);
+ else
+ printf ("%s-next-openstep%d\n", __ARCHITECTURE__, version);
+ exit (0);
+#endif
+
+#if defined (MULTIMAX) || defined (n16)
+#if defined (UMAXV)
+ printf ("ns32k-encore-sysv\n"); exit (0);
+#else
+#if defined (CMU)
+ printf ("ns32k-encore-mach\n"); exit (0);
+#else
+ printf ("ns32k-encore-bsd\n"); exit (0);
+#endif
+#endif
+#endif
+
+#if defined (__386BSD__)
+ printf ("i386-pc-bsd\n"); exit (0);
+#endif
+
+#if defined (sequent)
+#if defined (i386)
+ printf ("i386-sequent-dynix\n"); exit (0);
+#endif
+#if defined (ns32000)
+ printf ("ns32k-sequent-dynix\n"); exit (0);
+#endif
+#endif
+
+#if defined (_SEQUENT_)
+ struct utsname un;
+
+ uname(&un);
+
+ if (strncmp(un.version, "V2", 2) == 0) {
+ printf ("i386-sequent-ptx2\n"); exit (0);
+ }
+ if (strncmp(un.version, "V1", 2) == 0) { /* XXX is V1 correct? */
+ printf ("i386-sequent-ptx1\n"); exit (0);
+ }
+ printf ("i386-sequent-ptx\n"); exit (0);
+
+#endif
+
+#if defined (vax)
+# if !defined (ultrix)
+# include <sys/param.h>
+# if defined (BSD)
+# if BSD == 43
+ printf ("vax-dec-bsd4.3\n"); exit (0);
+# else
+# if BSD == 199006
+ printf ("vax-dec-bsd4.3reno\n"); exit (0);
+# else
+ printf ("vax-dec-bsd\n"); exit (0);
+# endif
+# endif
+# else
+ printf ("vax-dec-bsd\n"); exit (0);
+# endif
+# else
+ printf ("vax-dec-ultrix\n"); exit (0);
+# endif
+#endif
+
+#if defined (alliant) && defined (i860)
+ printf ("i860-alliant-bsd\n"); exit (0);
+#endif
+
+ exit (1);
+}
+EOF
+
+$CC_FOR_BUILD -o $dummy $dummy.c 2>/dev/null && SYSTEM_NAME=`$dummy` &&
+ { echo "$SYSTEM_NAME"; exit; }
+
+# Apollos put the system type in the environment.
+
+test -d /usr/apollo && { echo ${ISP}-apollo-${SYSTYPE}; exit; }
+
+# Convex versions that predate uname can use getsysinfo(1)
+
+if [ -x /usr/convex/getsysinfo ]
+then
+ case `getsysinfo -f cpu_type` in
+ c1*)
+ echo c1-convex-bsd
+ exit ;;
+ c2*)
+ if getsysinfo -f scalar_acc
+ then echo c32-convex-bsd
+ else echo c2-convex-bsd
+ fi
+ exit ;;
+ c34*)
+ echo c34-convex-bsd
+ exit ;;
+ c38*)
+ echo c38-convex-bsd
+ exit ;;
+ c4*)
+ echo c4-convex-bsd
+ exit ;;
+ esac
+fi
+
+cat >&2 <<EOF
+$0: unable to guess system type
+
+This script, last modified $timestamp, has failed to recognize
+the operating system you are using. It is advised that you
+download the most up to date version of the config scripts from
+
+ http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD
+and
+ http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD
+
+If the version you run ($0) is already up to date, please
+send the following data and any information you think might be
+pertinent to <config-patches@gnu.org> in order to provide the needed
+information to handle your system.
+
+config.guess timestamp = $timestamp
+
+uname -m = `(uname -m) 2>/dev/null || echo unknown`
+uname -r = `(uname -r) 2>/dev/null || echo unknown`
+uname -s = `(uname -s) 2>/dev/null || echo unknown`
+uname -v = `(uname -v) 2>/dev/null || echo unknown`
+
+/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null`
+/bin/uname -X = `(/bin/uname -X) 2>/dev/null`
+
+hostinfo = `(hostinfo) 2>/dev/null`
+/bin/universe = `(/bin/universe) 2>/dev/null`
+/usr/bin/arch -k = `(/usr/bin/arch -k) 2>/dev/null`
+/bin/arch = `(/bin/arch) 2>/dev/null`
+/usr/bin/oslevel = `(/usr/bin/oslevel) 2>/dev/null`
+/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null`
+
+UNAME_MACHINE = ${UNAME_MACHINE}
+UNAME_RELEASE = ${UNAME_RELEASE}
+UNAME_SYSTEM = ${UNAME_SYSTEM}
+UNAME_VERSION = ${UNAME_VERSION}
+EOF
+
+exit 1
+
+# Local variables:
+# eval: (add-hook 'write-file-hooks 'time-stamp)
+# time-stamp-start: "timestamp='"
+# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-end: "'"
+# End:
diff --git a/src/3rdparty/libpng/config.h.in b/src/3rdparty/libpng/config.h.in
new file mode 100644
index 0000000000..fb2349568c
--- /dev/null
+++ b/src/3rdparty/libpng/config.h.in
@@ -0,0 +1,86 @@
+/* config.h.in. Generated from configure.ac by autoheader. */
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#undef HAVE_DLFCN_H
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#undef HAVE_INTTYPES_H
+
+/* Define to 1 if you have the `m' library (-lm). */
+#undef HAVE_LIBM
+
+/* Define to 1 if you have the `z' library (-lz). */
+#undef HAVE_LIBZ
+
+/* Define to 1 if you have the <malloc.h> header file. */
+#undef HAVE_MALLOC_H
+
+/* Define to 1 if you have the <memory.h> header file. */
+#undef HAVE_MEMORY_H
+
+/* Define to 1 if you have the `memset' function. */
+#undef HAVE_MEMSET
+
+/* Define to 1 if you have the `pow' function. */
+#undef HAVE_POW
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#undef HAVE_STDINT_H
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#undef HAVE_STDLIB_H
+
+/* Define to 1 if you have the <strings.h> header file. */
+#undef HAVE_STRINGS_H
+
+/* Define to 1 if you have the <string.h> header file. */
+#undef HAVE_STRING_H
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#undef HAVE_SYS_STAT_H
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#undef HAVE_SYS_TYPES_H
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+ */
+#undef LT_OBJDIR
+
+/* Name of package */
+#undef PACKAGE
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
+
+/* Define to 1 if you have the ANSI C header files. */
+#undef STDC_HEADERS
+
+/* Define to 1 if your <sys/time.h> declares `struct tm'. */
+#undef TM_IN_SYS_TIME
+
+/* Version number of package */
+#undef VERSION
+
+/* Define to empty if `const' does not conform to ANSI C. */
+#undef const
+
+/* Define to `unsigned int' if <sys/types.h> does not define. */
+#undef size_t
diff --git a/src/3rdparty/libpng/config.sub b/src/3rdparty/libpng/config.sub
new file mode 100644
index 0000000000..2a55a50751
--- /dev/null
+++ b/src/3rdparty/libpng/config.sub
@@ -0,0 +1,1705 @@
+#! /bin/sh
+# Configuration validation subroutine script.
+# Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+# 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+# Free Software Foundation, Inc.
+
+timestamp='2009-11-20'
+
+# This file is (in principle) common to ALL GNU software.
+# The presence of a machine in this file suggests that SOME GNU software
+# can handle that machine. It does not imply ALL GNU software can.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
+# 02110-1301, USA.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+
+# Please send patches to <config-patches@gnu.org>. Submit a context
+# diff and a properly formatted GNU ChangeLog entry.
+#
+# Configuration subroutine to validate and canonicalize a configuration type.
+# Supply the specified configuration type as an argument.
+# If it is invalid, we print an error message on stderr and exit with code 1.
+# Otherwise, we print the canonical config type on stdout and succeed.
+
+# You can get the latest version of this script from:
+# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD
+
+# This file is supposed to be the same for all GNU packages
+# and recognize all the CPU types, system types and aliases
+# that are meaningful with *any* GNU software.
+# Each package is responsible for reporting which valid configurations
+# it does not support. The user should be able to distinguish
+# a failure to support a valid configuration from a meaningless
+# configuration.
+
+# The goal of this file is to map all the various variations of a given
+# machine specification into a single specification in the form:
+# CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM
+# or in some cases, the newer four-part form:
+# CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM
+# It is wrong to echo any other type of specification.
+
+me=`echo "$0" | sed -e 's,.*/,,'`
+
+usage="\
+Usage: $0 [OPTION] CPU-MFR-OPSYS
+ $0 [OPTION] ALIAS
+
+Canonicalize a configuration name.
+
+Operation modes:
+ -h, --help print this help, then exit
+ -t, --time-stamp print date of last modification, then exit
+ -v, --version print version number, then exit
+
+Report bugs and patches to <config-patches@gnu.org>."
+
+version="\
+GNU config.sub ($timestamp)
+
+Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+
+This is free software; see the source for copying conditions. There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
+
+help="
+Try \`$me --help' for more information."
+
+# Parse command line
+while test $# -gt 0 ; do
+ case $1 in
+ --time-stamp | --time* | -t )
+ echo "$timestamp" ; exit ;;
+ --version | -v )
+ echo "$version" ; exit ;;
+ --help | --h* | -h )
+ echo "$usage"; exit ;;
+ -- ) # Stop option processing
+ shift; break ;;
+ - ) # Use stdin as input.
+ break ;;
+ -* )
+ echo "$me: invalid option $1$help"
+ exit 1 ;;
+
+ *local*)
+ # First pass through any local machine types.
+ echo $1
+ exit ;;
+
+ * )
+ break ;;
+ esac
+done
+
+case $# in
+ 0) echo "$me: missing argument$help" >&2
+ exit 1;;
+ 1) ;;
+ *) echo "$me: too many arguments$help" >&2
+ exit 1;;
+esac
+
+# Separate what the user gave into CPU-COMPANY and OS or KERNEL-OS (if any).
+# Here we must recognize all the valid KERNEL-OS combinations.
+maybe_os=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
+case $maybe_os in
+ nto-qnx* | linux-gnu* | linux-dietlibc | linux-newlib* | linux-uclibc* | \
+ uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | knetbsd*-gnu* | netbsd*-gnu* | \
+ kopensolaris*-gnu* | \
+ storm-chaos* | os2-emx* | rtmk-nova*)
+ os=-$maybe_os
+ basic_machine=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`
+ ;;
+ *)
+ basic_machine=`echo $1 | sed 's/-[^-]*$//'`
+ if [ $basic_machine != $1 ]
+ then os=`echo $1 | sed 's/.*-/-/'`
+ else os=; fi
+ ;;
+esac
+
+### Let's recognize common machines as not being operating systems so
+### that things like config.sub decstation-3100 work. We also
+### recognize some manufacturers as not being operating systems, so we
+### can provide default operating systems below.
+case $os in
+ -sun*os*)
+ # Prevent following clause from handling this invalid input.
+ ;;
+ -dec* | -mips* | -sequent* | -encore* | -pc532* | -sgi* | -sony* | \
+ -att* | -7300* | -3300* | -delta* | -motorola* | -sun[234]* | \
+ -unicom* | -ibm* | -next | -hp | -isi* | -apollo | -altos* | \
+ -convergent* | -ncr* | -news | -32* | -3600* | -3100* | -hitachi* |\
+ -c[123]* | -convex* | -sun | -crds | -omron* | -dg | -ultra | -tti* | \
+ -harris | -dolphin | -highlevel | -gould | -cbm | -ns | -masscomp | \
+ -apple | -axis | -knuth | -cray | -microblaze)
+ os=
+ basic_machine=$1
+ ;;
+ -bluegene*)
+ os=-cnk
+ ;;
+ -sim | -cisco | -oki | -wec | -winbond)
+ os=
+ basic_machine=$1
+ ;;
+ -scout)
+ ;;
+ -wrs)
+ os=-vxworks
+ basic_machine=$1
+ ;;
+ -chorusos*)
+ os=-chorusos
+ basic_machine=$1
+ ;;
+ -chorusrdb)
+ os=-chorusrdb
+ basic_machine=$1
+ ;;
+ -hiux*)
+ os=-hiuxwe2
+ ;;
+ -sco6)
+ os=-sco5v6
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -sco5)
+ os=-sco3.2v5
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -sco4)
+ os=-sco3.2v4
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -sco3.2.[4-9]*)
+ os=`echo $os | sed -e 's/sco3.2./sco3.2v/'`
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -sco3.2v[4-9]*)
+ # Don't forget version if it is 3.2v4 or newer.
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -sco5v6*)
+ # Don't forget version if it is 3.2v4 or newer.
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -sco*)
+ os=-sco3.2v2
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -udk*)
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -isc)
+ os=-isc2.2
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -clix*)
+ basic_machine=clipper-intergraph
+ ;;
+ -isc*)
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
+ ;;
+ -lynx*)
+ os=-lynxos
+ ;;
+ -ptx*)
+ basic_machine=`echo $1 | sed -e 's/86-.*/86-sequent/'`
+ ;;
+ -windowsnt*)
+ os=`echo $os | sed -e 's/windowsnt/winnt/'`
+ ;;
+ -psos*)
+ os=-psos
+ ;;
+ -mint | -mint[0-9]*)
+ basic_machine=m68k-atari
+ os=-mint
+ ;;
+esac
+
+# Decode aliases for certain CPU-COMPANY combinations.
+case $basic_machine in
+ # Recognize the basic CPU types without company name.
+ # Some are omitted here because they have special meanings below.
+ 1750a | 580 \
+ | a29k \
+ | alpha | alphaev[4-8] | alphaev56 | alphaev6[78] | alphapca5[67] \
+ | alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] | alpha64pca5[67] \
+ | am33_2.0 \
+ | arc | arm | arm[bl]e | arme[lb] | armv[2345] | armv[345][lb] | avr | avr32 \
+ | bfin \
+ | c4x | clipper \
+ | d10v | d30v | dlx | dsp16xx \
+ | fido | fr30 | frv \
+ | h8300 | h8500 | hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
+ | i370 | i860 | i960 | ia64 \
+ | ip2k | iq2000 \
+ | lm32 \
+ | m32c | m32r | m32rle | m68000 | m68k | m88k \
+ | maxq | mb | microblaze | mcore | mep | metag \
+ | mips | mipsbe | mipseb | mipsel | mipsle \
+ | mips16 \
+ | mips64 | mips64el \
+ | mips64octeon | mips64octeonel \
+ | mips64orion | mips64orionel \
+ | mips64r5900 | mips64r5900el \
+ | mips64vr | mips64vrel \
+ | mips64vr4100 | mips64vr4100el \
+ | mips64vr4300 | mips64vr4300el \
+ | mips64vr5000 | mips64vr5000el \
+ | mips64vr5900 | mips64vr5900el \
+ | mipsisa32 | mipsisa32el \
+ | mipsisa32r2 | mipsisa32r2el \
+ | mipsisa64 | mipsisa64el \
+ | mipsisa64r2 | mipsisa64r2el \
+ | mipsisa64sb1 | mipsisa64sb1el \
+ | mipsisa64sr71k | mipsisa64sr71kel \
+ | mipstx39 | mipstx39el \
+ | mn10200 | mn10300 \
+ | moxie \
+ | mt \
+ | msp430 \
+ | nios | nios2 \
+ | ns16k | ns32k \
+ | or32 \
+ | pdp10 | pdp11 | pj | pjl \
+ | powerpc | powerpc64 | powerpc64le | powerpcle | ppcbe \
+ | pyramid \
+ | rx \
+ | score \
+ | sh | sh[1234] | sh[24]a | sh[24]aeb | sh[23]e | sh[34]eb | sheb | shbe | shle | sh[1234]le | sh3ele \
+ | sh64 | sh64le \
+ | sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet | sparclite \
+ | sparcv8 | sparcv9 | sparcv9b | sparcv9v \
+ | spu | strongarm \
+ | tahoe | thumb | tic4x | tic80 | tron \
+ | ubicom32 \
+ | v850 | v850e \
+ | we32k \
+ | x86 | xc16x | xscale | xscalee[bl] | xstormy16 | xtensa \
+ | z8k | z80)
+ basic_machine=$basic_machine-unknown
+ ;;
+ m6811 | m68hc11 | m6812 | m68hc12 | picochip)
+ # Motorola 68HC11/12.
+ basic_machine=$basic_machine-unknown
+ os=-none
+ ;;
+ m88110 | m680[12346]0 | m683?2 | m68360 | m5200 | v70 | w65 | z8k)
+ ;;
+ ms1)
+ basic_machine=mt-unknown
+ ;;
+
+ # We use `pc' rather than `unknown'
+ # because (1) that's what they normally are, and
+ # (2) the word "unknown" tends to confuse beginning users.
+ i*86 | x86_64)
+ basic_machine=$basic_machine-pc
+ ;;
+ # Object if more than one company name word.
+ *-*-*)
+ echo Invalid configuration \`$1\': machine \`$basic_machine\' not recognized 1>&2
+ exit 1
+ ;;
+ # Recognize the basic CPU types with company name.
+ 580-* \
+ | a29k-* \
+ | alpha-* | alphaev[4-8]-* | alphaev56-* | alphaev6[78]-* \
+ | alpha64-* | alpha64ev[4-8]-* | alpha64ev56-* | alpha64ev6[78]-* \
+ | alphapca5[67]-* | alpha64pca5[67]-* | arc-* \
+ | arm-* | armbe-* | armle-* | armeb-* | armv*-* \
+ | avr-* | avr32-* \
+ | bfin-* | bs2000-* \
+ | c[123]* | c30-* | [cjt]90-* | c4x-* | c54x-* | c55x-* | c6x-* \
+ | clipper-* | craynv-* | cydra-* \
+ | d10v-* | d30v-* | dlx-* \
+ | elxsi-* \
+ | f30[01]-* | f700-* | fido-* | fr30-* | frv-* | fx80-* \
+ | h8300-* | h8500-* \
+ | hppa-* | hppa1.[01]-* | hppa2.0-* | hppa2.0[nw]-* | hppa64-* \
+ | i*86-* | i860-* | i960-* | ia64-* \
+ | ip2k-* | iq2000-* \
+ | lm32-* \
+ | m32c-* | m32r-* | m32rle-* \
+ | m68000-* | m680[012346]0-* | m68360-* | m683?2-* | m68k-* \
+ | m88110-* | m88k-* | maxq-* | mcore-* | metag-* | microblaze-* \
+ | mips-* | mipsbe-* | mipseb-* | mipsel-* | mipsle-* \
+ | mips16-* \
+ | mips64-* | mips64el-* \
+ | mips64octeon-* | mips64octeonel-* \
+ | mips64orion-* | mips64orionel-* \
+ | mips64r5900-* | mips64r5900el-* \
+ | mips64vr-* | mips64vrel-* \
+ | mips64vr4100-* | mips64vr4100el-* \
+ | mips64vr4300-* | mips64vr4300el-* \
+ | mips64vr5000-* | mips64vr5000el-* \
+ | mips64vr5900-* | mips64vr5900el-* \
+ | mipsisa32-* | mipsisa32el-* \
+ | mipsisa32r2-* | mipsisa32r2el-* \
+ | mipsisa64-* | mipsisa64el-* \
+ | mipsisa64r2-* | mipsisa64r2el-* \
+ | mipsisa64sb1-* | mipsisa64sb1el-* \
+ | mipsisa64sr71k-* | mipsisa64sr71kel-* \
+ | mipstx39-* | mipstx39el-* \
+ | mmix-* \
+ | mt-* \
+ | msp430-* \
+ | nios-* | nios2-* \
+ | none-* | np1-* | ns16k-* | ns32k-* \
+ | orion-* \
+ | pdp10-* | pdp11-* | pj-* | pjl-* | pn-* | power-* \
+ | powerpc-* | powerpc64-* | powerpc64le-* | powerpcle-* | ppcbe-* \
+ | pyramid-* \
+ | romp-* | rs6000-* | rx-* \
+ | sh-* | sh[1234]-* | sh[24]a-* | sh[24]aeb-* | sh[23]e-* | sh[34]eb-* | sheb-* | shbe-* \
+ | shle-* | sh[1234]le-* | sh3ele-* | sh64-* | sh64le-* \
+ | sparc-* | sparc64-* | sparc64b-* | sparc64v-* | sparc86x-* | sparclet-* \
+ | sparclite-* \
+ | sparcv8-* | sparcv9-* | sparcv9b-* | sparcv9v-* | strongarm-* | sv1-* | sx?-* \
+ | tahoe-* | thumb-* \
+ | tic30-* | tic4x-* | tic54x-* | tic55x-* | tic6x-* | tic80-* | tile-* \
+ | tron-* \
+ | ubicom32-* \
+ | v850-* | v850e-* | vax-* \
+ | we32k-* \
+ | x86-* | x86_64-* | xc16x-* | xps100-* | xscale-* | xscalee[bl]-* \
+ | xstormy16-* | xtensa*-* \
+ | ymp-* \
+ | z8k-* | z80-*)
+ ;;
+ # Recognize the basic CPU types without company name, with glob match.
+ xtensa*)
+ basic_machine=$basic_machine-unknown
+ ;;
+ # Recognize the various machine names and aliases which stand
+ # for a CPU type and a company and sometimes even an OS.
+ 386bsd)
+ basic_machine=i386-unknown
+ os=-bsd
+ ;;
+ 3b1 | 7300 | 7300-att | att-7300 | pc7300 | safari | unixpc)
+ basic_machine=m68000-att
+ ;;
+ 3b*)
+ basic_machine=we32k-att
+ ;;
+ a29khif)
+ basic_machine=a29k-amd
+ os=-udi
+ ;;
+ abacus)
+ basic_machine=abacus-unknown
+ ;;
+ adobe68k)
+ basic_machine=m68010-adobe
+ os=-scout
+ ;;
+ alliant | fx80)
+ basic_machine=fx80-alliant
+ ;;
+ altos | altos3068)
+ basic_machine=m68k-altos
+ ;;
+ am29k)
+ basic_machine=a29k-none
+ os=-bsd
+ ;;
+ amd64)
+ basic_machine=x86_64-pc
+ ;;
+ amd64-*)
+ basic_machine=x86_64-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ amdahl)
+ basic_machine=580-amdahl
+ os=-sysv
+ ;;
+ amiga | amiga-*)
+ basic_machine=m68k-unknown
+ ;;
+ amigaos | amigados)
+ basic_machine=m68k-unknown
+ os=-amigaos
+ ;;
+ amigaunix | amix)
+ basic_machine=m68k-unknown
+ os=-sysv4
+ ;;
+ apollo68)
+ basic_machine=m68k-apollo
+ os=-sysv
+ ;;
+ apollo68bsd)
+ basic_machine=m68k-apollo
+ os=-bsd
+ ;;
+ aros)
+ basic_machine=i386-pc
+ os=-aros
+ ;;
+ aux)
+ basic_machine=m68k-apple
+ os=-aux
+ ;;
+ balance)
+ basic_machine=ns32k-sequent
+ os=-dynix
+ ;;
+ blackfin)
+ basic_machine=bfin-unknown
+ os=-linux
+ ;;
+ blackfin-*)
+ basic_machine=bfin-`echo $basic_machine | sed 's/^[^-]*-//'`
+ os=-linux
+ ;;
+ bluegene*)
+ basic_machine=powerpc-ibm
+ os=-cnk
+ ;;
+ c90)
+ basic_machine=c90-cray
+ os=-unicos
+ ;;
+ cegcc)
+ basic_machine=arm-unknown
+ os=-cegcc
+ ;;
+ convex-c1)
+ basic_machine=c1-convex
+ os=-bsd
+ ;;
+ convex-c2)
+ basic_machine=c2-convex
+ os=-bsd
+ ;;
+ convex-c32)
+ basic_machine=c32-convex
+ os=-bsd
+ ;;
+ convex-c34)
+ basic_machine=c34-convex
+ os=-bsd
+ ;;
+ convex-c38)
+ basic_machine=c38-convex
+ os=-bsd
+ ;;
+ cray | j90)
+ basic_machine=j90-cray
+ os=-unicos
+ ;;
+ craynv)
+ basic_machine=craynv-cray
+ os=-unicosmp
+ ;;
+ cr16)
+ basic_machine=cr16-unknown
+ os=-elf
+ ;;
+ crds | unos)
+ basic_machine=m68k-crds
+ ;;
+ crisv32 | crisv32-* | etraxfs*)
+ basic_machine=crisv32-axis
+ ;;
+ cris | cris-* | etrax*)
+ basic_machine=cris-axis
+ ;;
+ crx)
+ basic_machine=crx-unknown
+ os=-elf
+ ;;
+ da30 | da30-*)
+ basic_machine=m68k-da30
+ ;;
+ decstation | decstation-3100 | pmax | pmax-* | pmin | dec3100 | decstatn)
+ basic_machine=mips-dec
+ ;;
+ decsystem10* | dec10*)
+ basic_machine=pdp10-dec
+ os=-tops10
+ ;;
+ decsystem20* | dec20*)
+ basic_machine=pdp10-dec
+ os=-tops20
+ ;;
+ delta | 3300 | motorola-3300 | motorola-delta \
+ | 3300-motorola | delta-motorola)
+ basic_machine=m68k-motorola
+ ;;
+ delta88)
+ basic_machine=m88k-motorola
+ os=-sysv3
+ ;;
+ dicos)
+ basic_machine=i686-pc
+ os=-dicos
+ ;;
+ djgpp)
+ basic_machine=i586-pc
+ os=-msdosdjgpp
+ ;;
+ dpx20 | dpx20-*)
+ basic_machine=rs6000-bull
+ os=-bosx
+ ;;
+ dpx2* | dpx2*-bull)
+ basic_machine=m68k-bull
+ os=-sysv3
+ ;;
+ ebmon29k)
+ basic_machine=a29k-amd
+ os=-ebmon
+ ;;
+ elxsi)
+ basic_machine=elxsi-elxsi
+ os=-bsd
+ ;;
+ encore | umax | mmax)
+ basic_machine=ns32k-encore
+ ;;
+ es1800 | OSE68k | ose68k | ose | OSE)
+ basic_machine=m68k-ericsson
+ os=-ose
+ ;;
+ fx2800)
+ basic_machine=i860-alliant
+ ;;
+ genix)
+ basic_machine=ns32k-ns
+ ;;
+ gmicro)
+ basic_machine=tron-gmicro
+ os=-sysv
+ ;;
+ go32)
+ basic_machine=i386-pc
+ os=-go32
+ ;;
+ h3050r* | hiux*)
+ basic_machine=hppa1.1-hitachi
+ os=-hiuxwe2
+ ;;
+ h8300hms)
+ basic_machine=h8300-hitachi
+ os=-hms
+ ;;
+ h8300xray)
+ basic_machine=h8300-hitachi
+ os=-xray
+ ;;
+ h8500hms)
+ basic_machine=h8500-hitachi
+ os=-hms
+ ;;
+ harris)
+ basic_machine=m88k-harris
+ os=-sysv3
+ ;;
+ hp300-*)
+ basic_machine=m68k-hp
+ ;;
+ hp300bsd)
+ basic_machine=m68k-hp
+ os=-bsd
+ ;;
+ hp300hpux)
+ basic_machine=m68k-hp
+ os=-hpux
+ ;;
+ hp3k9[0-9][0-9] | hp9[0-9][0-9])
+ basic_machine=hppa1.0-hp
+ ;;
+ hp9k2[0-9][0-9] | hp9k31[0-9])
+ basic_machine=m68000-hp
+ ;;
+ hp9k3[2-9][0-9])
+ basic_machine=m68k-hp
+ ;;
+ hp9k6[0-9][0-9] | hp6[0-9][0-9])
+ basic_machine=hppa1.0-hp
+ ;;
+ hp9k7[0-79][0-9] | hp7[0-79][0-9])
+ basic_machine=hppa1.1-hp
+ ;;
+ hp9k78[0-9] | hp78[0-9])
+ # FIXME: really hppa2.0-hp
+ basic_machine=hppa1.1-hp
+ ;;
+ hp9k8[67]1 | hp8[67]1 | hp9k80[24] | hp80[24] | hp9k8[78]9 | hp8[78]9 | hp9k893 | hp893)
+ # FIXME: really hppa2.0-hp
+ basic_machine=hppa1.1-hp
+ ;;
+ hp9k8[0-9][13679] | hp8[0-9][13679])
+ basic_machine=hppa1.1-hp
+ ;;
+ hp9k8[0-9][0-9] | hp8[0-9][0-9])
+ basic_machine=hppa1.0-hp
+ ;;
+ hppa-next)
+ os=-nextstep3
+ ;;
+ hppaosf)
+ basic_machine=hppa1.1-hp
+ os=-osf
+ ;;
+ hppro)
+ basic_machine=hppa1.1-hp
+ os=-proelf
+ ;;
+ i370-ibm* | ibm*)
+ basic_machine=i370-ibm
+ ;;
+# I'm not sure what "Sysv32" means. Should this be sysv3.2?
+ i*86v32)
+ basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
+ os=-sysv32
+ ;;
+ i*86v4*)
+ basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
+ os=-sysv4
+ ;;
+ i*86v)
+ basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
+ os=-sysv
+ ;;
+ i*86sol2)
+ basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
+ os=-solaris2
+ ;;
+ i386mach)
+ basic_machine=i386-mach
+ os=-mach
+ ;;
+ i386-vsta | vsta)
+ basic_machine=i386-unknown
+ os=-vsta
+ ;;
+ iris | iris4d)
+ basic_machine=mips-sgi
+ case $os in
+ -irix*)
+ ;;
+ *)
+ os=-irix4
+ ;;
+ esac
+ ;;
+ isi68 | isi)
+ basic_machine=m68k-isi
+ os=-sysv
+ ;;
+ m68knommu)
+ basic_machine=m68k-unknown
+ os=-linux
+ ;;
+ m68knommu-*)
+ basic_machine=m68k-`echo $basic_machine | sed 's/^[^-]*-//'`
+ os=-linux
+ ;;
+ m88k-omron*)
+ basic_machine=m88k-omron
+ ;;
+ magnum | m3230)
+ basic_machine=mips-mips
+ os=-sysv
+ ;;
+ merlin)
+ basic_machine=ns32k-utek
+ os=-sysv
+ ;;
+ microblaze)
+ basic_machine=microblaze-xilinx
+ ;;
+ mingw32)
+ basic_machine=i386-pc
+ os=-mingw32
+ ;;
+ mingw32ce)
+ basic_machine=arm-unknown
+ os=-mingw32ce
+ ;;
+ miniframe)
+ basic_machine=m68000-convergent
+ ;;
+ *mint | -mint[0-9]* | *MiNT | *MiNT[0-9]*)
+ basic_machine=m68k-atari
+ os=-mint
+ ;;
+ mips3*-*)
+ basic_machine=`echo $basic_machine | sed -e 's/mips3/mips64/'`
+ ;;
+ mips3*)
+ basic_machine=`echo $basic_machine | sed -e 's/mips3/mips64/'`-unknown
+ ;;
+ monitor)
+ basic_machine=m68k-rom68k
+ os=-coff
+ ;;
+ morphos)
+ basic_machine=powerpc-unknown
+ os=-morphos
+ ;;
+ msdos)
+ basic_machine=i386-pc
+ os=-msdos
+ ;;
+ ms1-*)
+ basic_machine=`echo $basic_machine | sed -e 's/ms1-/mt-/'`
+ ;;
+ mvs)
+ basic_machine=i370-ibm
+ os=-mvs
+ ;;
+ ncr3000)
+ basic_machine=i486-ncr
+ os=-sysv4
+ ;;
+ netbsd386)
+ basic_machine=i386-unknown
+ os=-netbsd
+ ;;
+ netwinder)
+ basic_machine=armv4l-rebel
+ os=-linux
+ ;;
+ news | news700 | news800 | news900)
+ basic_machine=m68k-sony
+ os=-newsos
+ ;;
+ news1000)
+ basic_machine=m68030-sony
+ os=-newsos
+ ;;
+ news-3600 | risc-news)
+ basic_machine=mips-sony
+ os=-newsos
+ ;;
+ necv70)
+ basic_machine=v70-nec
+ os=-sysv
+ ;;
+ next | m*-next )
+ basic_machine=m68k-next
+ case $os in
+ -nextstep* )
+ ;;
+ -ns2*)
+ os=-nextstep2
+ ;;
+ *)
+ os=-nextstep3
+ ;;
+ esac
+ ;;
+ nh3000)
+ basic_machine=m68k-harris
+ os=-cxux
+ ;;
+ nh[45]000)
+ basic_machine=m88k-harris
+ os=-cxux
+ ;;
+ nindy960)
+ basic_machine=i960-intel
+ os=-nindy
+ ;;
+ mon960)
+ basic_machine=i960-intel
+ os=-mon960
+ ;;
+ nonstopux)
+ basic_machine=mips-compaq
+ os=-nonstopux
+ ;;
+ np1)
+ basic_machine=np1-gould
+ ;;
+ nsr-tandem)
+ basic_machine=nsr-tandem
+ ;;
+ op50n-* | op60c-*)
+ basic_machine=hppa1.1-oki
+ os=-proelf
+ ;;
+ openrisc | openrisc-*)
+ basic_machine=or32-unknown
+ ;;
+ os400)
+ basic_machine=powerpc-ibm
+ os=-os400
+ ;;
+ OSE68000 | ose68000)
+ basic_machine=m68000-ericsson
+ os=-ose
+ ;;
+ os68k)
+ basic_machine=m68k-none
+ os=-os68k
+ ;;
+ pa-hitachi)
+ basic_machine=hppa1.1-hitachi
+ os=-hiuxwe2
+ ;;
+ paragon)
+ basic_machine=i860-intel
+ os=-osf
+ ;;
+ parisc)
+ basic_machine=hppa-unknown
+ os=-linux
+ ;;
+ parisc-*)
+ basic_machine=hppa-`echo $basic_machine | sed 's/^[^-]*-//'`
+ os=-linux
+ ;;
+ pbd)
+ basic_machine=sparc-tti
+ ;;
+ pbb)
+ basic_machine=m68k-tti
+ ;;
+ pc532 | pc532-*)
+ basic_machine=ns32k-pc532
+ ;;
+ pc98)
+ basic_machine=i386-pc
+ ;;
+ pc98-*)
+ basic_machine=i386-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ pentium | p5 | k5 | k6 | nexgen | viac3)
+ basic_machine=i586-pc
+ ;;
+ pentiumpro | p6 | 6x86 | athlon | athlon_*)
+ basic_machine=i686-pc
+ ;;
+ pentiumii | pentium2 | pentiumiii | pentium3)
+ basic_machine=i686-pc
+ ;;
+ pentium4)
+ basic_machine=i786-pc
+ ;;
+ pentium-* | p5-* | k5-* | k6-* | nexgen-* | viac3-*)
+ basic_machine=i586-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ pentiumpro-* | p6-* | 6x86-* | athlon-*)
+ basic_machine=i686-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ pentiumii-* | pentium2-* | pentiumiii-* | pentium3-*)
+ basic_machine=i686-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ pentium4-*)
+ basic_machine=i786-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ pn)
+ basic_machine=pn-gould
+ ;;
+ power) basic_machine=power-ibm
+ ;;
+ ppc) basic_machine=powerpc-unknown
+ ;;
+ ppc-*) basic_machine=powerpc-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ ppcle | powerpclittle | ppc-le | powerpc-little)
+ basic_machine=powerpcle-unknown
+ ;;
+ ppcle-* | powerpclittle-*)
+ basic_machine=powerpcle-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ ppc64) basic_machine=powerpc64-unknown
+ ;;
+ ppc64-*) basic_machine=powerpc64-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ ppc64le | powerpc64little | ppc64-le | powerpc64-little)
+ basic_machine=powerpc64le-unknown
+ ;;
+ ppc64le-* | powerpc64little-*)
+ basic_machine=powerpc64le-`echo $basic_machine | sed 's/^[^-]*-//'`
+ ;;
+ ps2)
+ basic_machine=i386-ibm
+ ;;
+ pw32)
+ basic_machine=i586-unknown
+ os=-pw32
+ ;;
+ rdos)
+ basic_machine=i386-pc
+ os=-rdos
+ ;;
+ rom68k)
+ basic_machine=m68k-rom68k
+ os=-coff
+ ;;
+ rm[46]00)
+ basic_machine=mips-siemens
+ ;;
+ rtpc | rtpc-*)
+ basic_machine=romp-ibm
+ ;;
+ s390 | s390-*)
+ basic_machine=s390-ibm
+ ;;
+ s390x | s390x-*)
+ basic_machine=s390x-ibm
+ ;;
+ sa29200)
+ basic_machine=a29k-amd
+ os=-udi
+ ;;
+ sb1)
+ basic_machine=mipsisa64sb1-unknown
+ ;;
+ sb1el)
+ basic_machine=mipsisa64sb1el-unknown
+ ;;
+ sde)
+ basic_machine=mipsisa32-sde
+ os=-elf
+ ;;
+ sei)
+ basic_machine=mips-sei
+ os=-seiux
+ ;;
+ sequent)
+ basic_machine=i386-sequent
+ ;;
+ sh)
+ basic_machine=sh-hitachi
+ os=-hms
+ ;;
+ sh5el)
+ basic_machine=sh5le-unknown
+ ;;
+ sh64)
+ basic_machine=sh64-unknown
+ ;;
+ sparclite-wrs | simso-wrs)
+ basic_machine=sparclite-wrs
+ os=-vxworks
+ ;;
+ sps7)
+ basic_machine=m68k-bull
+ os=-sysv2
+ ;;
+ spur)
+ basic_machine=spur-unknown
+ ;;
+ st2000)
+ basic_machine=m68k-tandem
+ ;;
+ stratus)
+ basic_machine=i860-stratus
+ os=-sysv4
+ ;;
+ sun2)
+ basic_machine=m68000-sun
+ ;;
+ sun2os3)
+ basic_machine=m68000-sun
+ os=-sunos3
+ ;;
+ sun2os4)
+ basic_machine=m68000-sun
+ os=-sunos4
+ ;;
+ sun3os3)
+ basic_machine=m68k-sun
+ os=-sunos3
+ ;;
+ sun3os4)
+ basic_machine=m68k-sun
+ os=-sunos4
+ ;;
+ sun4os3)
+ basic_machine=sparc-sun
+ os=-sunos3
+ ;;
+ sun4os4)
+ basic_machine=sparc-sun
+ os=-sunos4
+ ;;
+ sun4sol2)
+ basic_machine=sparc-sun
+ os=-solaris2
+ ;;
+ sun3 | sun3-*)
+ basic_machine=m68k-sun
+ ;;
+ sun4)
+ basic_machine=sparc-sun
+ ;;
+ sun386 | sun386i | roadrunner)
+ basic_machine=i386-sun
+ ;;
+ sv1)
+ basic_machine=sv1-cray
+ os=-unicos
+ ;;
+ symmetry)
+ basic_machine=i386-sequent
+ os=-dynix
+ ;;
+ t3e)
+ basic_machine=alphaev5-cray
+ os=-unicos
+ ;;
+ t90)
+ basic_machine=t90-cray
+ os=-unicos
+ ;;
+ tic54x | c54x*)
+ basic_machine=tic54x-unknown
+ os=-coff
+ ;;
+ tic55x | c55x*)
+ basic_machine=tic55x-unknown
+ os=-coff
+ ;;
+ tic6x | c6x*)
+ basic_machine=tic6x-unknown
+ os=-coff
+ ;;
+ tile*)
+ basic_machine=tile-unknown
+ os=-linux-gnu
+ ;;
+ tx39)
+ basic_machine=mipstx39-unknown
+ ;;
+ tx39el)
+ basic_machine=mipstx39el-unknown
+ ;;
+ toad1)
+ basic_machine=pdp10-xkl
+ os=-tops20
+ ;;
+ tower | tower-32)
+ basic_machine=m68k-ncr
+ ;;
+ tpf)
+ basic_machine=s390x-ibm
+ os=-tpf
+ ;;
+ udi29k)
+ basic_machine=a29k-amd
+ os=-udi
+ ;;
+ ultra3)
+ basic_machine=a29k-nyu
+ os=-sym1
+ ;;
+ v810 | necv810)
+ basic_machine=v810-nec
+ os=-none
+ ;;
+ vaxv)
+ basic_machine=vax-dec
+ os=-sysv
+ ;;
+ vms)
+ basic_machine=vax-dec
+ os=-vms
+ ;;
+ vpp*|vx|vx-*)
+ basic_machine=f301-fujitsu
+ ;;
+ vxworks960)
+ basic_machine=i960-wrs
+ os=-vxworks
+ ;;
+ vxworks68)
+ basic_machine=m68k-wrs
+ os=-vxworks
+ ;;
+ vxworks29k)
+ basic_machine=a29k-wrs
+ os=-vxworks
+ ;;
+ w65*)
+ basic_machine=w65-wdc
+ os=-none
+ ;;
+ w89k-*)
+ basic_machine=hppa1.1-winbond
+ os=-proelf
+ ;;
+ xbox)
+ basic_machine=i686-pc
+ os=-mingw32
+ ;;
+ xps | xps100)
+ basic_machine=xps100-honeywell
+ ;;
+ ymp)
+ basic_machine=ymp-cray
+ os=-unicos
+ ;;
+ z8k-*-coff)
+ basic_machine=z8k-unknown
+ os=-sim
+ ;;
+ z80-*-coff)
+ basic_machine=z80-unknown
+ os=-sim
+ ;;
+ none)
+ basic_machine=none-none
+ os=-none
+ ;;
+
+# Here we handle the default manufacturer of certain CPU types. It is in
+# some cases the only manufacturer, in others, it is the most popular.
+ w89k)
+ basic_machine=hppa1.1-winbond
+ ;;
+ op50n)
+ basic_machine=hppa1.1-oki
+ ;;
+ op60c)
+ basic_machine=hppa1.1-oki
+ ;;
+ romp)
+ basic_machine=romp-ibm
+ ;;
+ mmix)
+ basic_machine=mmix-knuth
+ ;;
+ rs6000)
+ basic_machine=rs6000-ibm
+ ;;
+ vax)
+ basic_machine=vax-dec
+ ;;
+ pdp10)
+ # there are many clones, so DEC is not a safe bet
+ basic_machine=pdp10-unknown
+ ;;
+ pdp11)
+ basic_machine=pdp11-dec
+ ;;
+ we32k)
+ basic_machine=we32k-att
+ ;;
+ sh[1234] | sh[24]a | sh[24]aeb | sh[34]eb | sh[1234]le | sh[23]ele)
+ basic_machine=sh-unknown
+ ;;
+ sparc | sparcv8 | sparcv9 | sparcv9b | sparcv9v)
+ basic_machine=sparc-sun
+ ;;
+ cydra)
+ basic_machine=cydra-cydrome
+ ;;
+ orion)
+ basic_machine=orion-highlevel
+ ;;
+ orion105)
+ basic_machine=clipper-highlevel
+ ;;
+ mac | mpw | mac-mpw)
+ basic_machine=m68k-apple
+ ;;
+ pmac | pmac-mpw)
+ basic_machine=powerpc-apple
+ ;;
+ *-unknown)
+ # Make sure to match an already-canonicalized machine name.
+ ;;
+ *)
+ echo Invalid configuration \`$1\': machine \`$basic_machine\' not recognized 1>&2
+ exit 1
+ ;;
+esac
+
+# Here we canonicalize certain aliases for manufacturers.
+case $basic_machine in
+ *-digital*)
+ basic_machine=`echo $basic_machine | sed 's/digital.*/dec/'`
+ ;;
+ *-commodore*)
+ basic_machine=`echo $basic_machine | sed 's/commodore.*/cbm/'`
+ ;;
+ *)
+ ;;
+esac
+
+# Decode manufacturer-specific aliases for certain operating systems.
+
+if [ x"$os" != x"" ]
+then
+case $os in
+ # First match some system type aliases
+ # that might get confused with valid system types.
+ # -solaris* is a basic system type, with this one exception.
+ -auroraux)
+ os=-auroraux
+ ;;
+ -solaris1 | -solaris1.*)
+ os=`echo $os | sed -e 's|solaris1|sunos4|'`
+ ;;
+ -solaris)
+ os=-solaris2
+ ;;
+ -svr4*)
+ os=-sysv4
+ ;;
+ -unixware*)
+ os=-sysv4.2uw
+ ;;
+ -gnu/linux*)
+ os=`echo $os | sed -e 's|gnu/linux|linux-gnu|'`
+ ;;
+ # First accept the basic system types.
+ # The portable systems comes first.
+ # Each alternative MUST END IN A *, to match a version number.
+ # -sysv* is not here because it comes later, after sysvr4.
+ -gnu* | -bsd* | -mach* | -minix* | -genix* | -ultrix* | -irix* \
+ | -*vms* | -sco* | -esix* | -isc* | -aix* | -cnk* | -sunos | -sunos[34]*\
+ | -hpux* | -unos* | -osf* | -luna* | -dgux* | -auroraux* | -solaris* \
+ | -sym* | -kopensolaris* \
+ | -amigaos* | -amigados* | -msdos* | -newsos* | -unicos* | -aof* \
+ | -aos* | -aros* \
+ | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
+ | -clix* | -riscos* | -uniplus* | -iris* | -rtu* | -xenix* \
+ | -hiux* | -386bsd* | -knetbsd* | -mirbsd* | -netbsd* \
+ | -openbsd* | -solidbsd* \
+ | -ekkobsd* | -kfreebsd* | -freebsd* | -riscix* | -lynxos* \
+ | -bosx* | -nextstep* | -cxux* | -aout* | -elf* | -oabi* \
+ | -ptx* | -coff* | -ecoff* | -winnt* | -domain* | -vsta* \
+ | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* \
+ | -chorusos* | -chorusrdb* | -cegcc* \
+ | -cygwin* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
+ | -mingw32* | -linux-gnu* | -linux-newlib* | -linux-uclibc* \
+ | -uxpv* | -beos* | -mpeix* | -udk* \
+ | -interix* | -uwin* | -mks* | -rhapsody* | -darwin* | -opened* \
+ | -openstep* | -oskit* | -conix* | -pw32* | -nonstopux* \
+ | -storm-chaos* | -tops10* | -tenex* | -tops20* | -its* \
+ | -os2* | -vos* | -palmos* | -uclinux* | -nucleus* \
+ | -morphos* | -superux* | -rtmk* | -rtmk-nova* | -windiss* \
+ | -powermax* | -dnix* | -nx6 | -nx7 | -sei* | -dragonfly* \
+ | -skyos* | -haiku* | -rdos* | -toppers* | -drops* | -es*)
+ # Remember, each alternative MUST END IN *, to match a version number.
+ ;;
+ -qnx*)
+ case $basic_machine in
+ x86-* | i*86-*)
+ ;;
+ *)
+ os=-nto$os
+ ;;
+ esac
+ ;;
+ -nto-qnx*)
+ ;;
+ -nto*)
+ os=`echo $os | sed -e 's|nto|nto-qnx|'`
+ ;;
+ -sim | -es1800* | -hms* | -xray | -os68k* | -none* | -v88r* \
+ | -windows* | -osx | -abug | -netware* | -os9* | -beos* | -haiku* \
+ | -macos* | -mpw* | -magic* | -mmixware* | -mon960* | -lnews*)
+ ;;
+ -mac*)
+ os=`echo $os | sed -e 's|mac|macos|'`
+ ;;
+ -linux-dietlibc)
+ os=-linux-dietlibc
+ ;;
+ -linux*)
+ os=`echo $os | sed -e 's|linux|linux-gnu|'`
+ ;;
+ -sunos5*)
+ os=`echo $os | sed -e 's|sunos5|solaris2|'`
+ ;;
+ -sunos6*)
+ os=`echo $os | sed -e 's|sunos6|solaris3|'`
+ ;;
+ -opened*)
+ os=-openedition
+ ;;
+ -os400*)
+ os=-os400
+ ;;
+ -wince*)
+ os=-wince
+ ;;
+ -osfrose*)
+ os=-osfrose
+ ;;
+ -osf*)
+ os=-osf
+ ;;
+ -utek*)
+ os=-bsd
+ ;;
+ -dynix*)
+ os=-bsd
+ ;;
+ -acis*)
+ os=-aos
+ ;;
+ -atheos*)
+ os=-atheos
+ ;;
+ -syllable*)
+ os=-syllable
+ ;;
+ -386bsd)
+ os=-bsd
+ ;;
+ -ctix* | -uts*)
+ os=-sysv
+ ;;
+ -nova*)
+ os=-rtmk-nova
+ ;;
+ -ns2 )
+ os=-nextstep2
+ ;;
+ -nsk*)
+ os=-nsk
+ ;;
+ # Preserve the version number of sinix5.
+ -sinix5.*)
+ os=`echo $os | sed -e 's|sinix|sysv|'`
+ ;;
+ -sinix*)
+ os=-sysv4
+ ;;
+ -tpf*)
+ os=-tpf
+ ;;
+ -triton*)
+ os=-sysv3
+ ;;
+ -oss*)
+ os=-sysv3
+ ;;
+ -svr4)
+ os=-sysv4
+ ;;
+ -svr3)
+ os=-sysv3
+ ;;
+ -sysvr4)
+ os=-sysv4
+ ;;
+ # This must come after -sysvr4.
+ -sysv*)
+ ;;
+ -ose*)
+ os=-ose
+ ;;
+ -es1800*)
+ os=-ose
+ ;;
+ -xenix)
+ os=-xenix
+ ;;
+ -*mint | -mint[0-9]* | -*MiNT | -MiNT[0-9]*)
+ os=-mint
+ ;;
+ -aros*)
+ os=-aros
+ ;;
+ -kaos*)
+ os=-kaos
+ ;;
+ -zvmoe)
+ os=-zvmoe
+ ;;
+ -dicos*)
+ os=-dicos
+ ;;
+ -none)
+ ;;
+ *)
+ # Get rid of the `-' at the beginning of $os.
+ os=`echo $os | sed 's/[^-]*-//'`
+ echo Invalid configuration \`$1\': system \`$os\' not recognized 1>&2
+ exit 1
+ ;;
+esac
+else
+
+# Here we handle the default operating systems that come with various machines.
+# The value should be what the vendor currently ships out the door with their
+# machine or put another way, the most popular os provided with the machine.
+
+# Note that if you're going to try to match "-MANUFACTURER" here (say,
+# "-sun"), then you have to tell the case statement up towards the top
+# that MANUFACTURER isn't an operating system. Otherwise, code above
+# will signal an error saying that MANUFACTURER isn't an operating
+# system, and we'll never get to this point.
+
+case $basic_machine in
+ score-*)
+ os=-elf
+ ;;
+ spu-*)
+ os=-elf
+ ;;
+ *-acorn)
+ os=-riscix1.2
+ ;;
+ arm*-rebel)
+ os=-linux
+ ;;
+ arm*-semi)
+ os=-aout
+ ;;
+ c4x-* | tic4x-*)
+ os=-coff
+ ;;
+ # This must come before the *-dec entry.
+ pdp10-*)
+ os=-tops20
+ ;;
+ pdp11-*)
+ os=-none
+ ;;
+ *-dec | vax-*)
+ os=-ultrix4.2
+ ;;
+ m68*-apollo)
+ os=-domain
+ ;;
+ i386-sun)
+ os=-sunos4.0.2
+ ;;
+ m68000-sun)
+ os=-sunos3
+ # This also exists in the configure program, but was not the
+ # default.
+ # os=-sunos4
+ ;;
+ m68*-cisco)
+ os=-aout
+ ;;
+ mep-*)
+ os=-elf
+ ;;
+ mips*-cisco)
+ os=-elf
+ ;;
+ mips*-*)
+ os=-elf
+ ;;
+ or32-*)
+ os=-coff
+ ;;
+ *-tti) # must be before sparc entry or we get the wrong os.
+ os=-sysv3
+ ;;
+ sparc-* | *-sun)
+ os=-sunos4.1.1
+ ;;
+ *-be)
+ os=-beos
+ ;;
+ *-haiku)
+ os=-haiku
+ ;;
+ *-ibm)
+ os=-aix
+ ;;
+ *-knuth)
+ os=-mmixware
+ ;;
+ *-wec)
+ os=-proelf
+ ;;
+ *-winbond)
+ os=-proelf
+ ;;
+ *-oki)
+ os=-proelf
+ ;;
+ *-hp)
+ os=-hpux
+ ;;
+ *-hitachi)
+ os=-hiux
+ ;;
+ i860-* | *-att | *-ncr | *-altos | *-motorola | *-convergent)
+ os=-sysv
+ ;;
+ *-cbm)
+ os=-amigaos
+ ;;
+ *-dg)
+ os=-dgux
+ ;;
+ *-dolphin)
+ os=-sysv3
+ ;;
+ m68k-ccur)
+ os=-rtu
+ ;;
+ m88k-omron*)
+ os=-luna
+ ;;
+ *-next )
+ os=-nextstep
+ ;;
+ *-sequent)
+ os=-ptx
+ ;;
+ *-crds)
+ os=-unos
+ ;;
+ *-ns)
+ os=-genix
+ ;;
+ i370-*)
+ os=-mvs
+ ;;
+ *-next)
+ os=-nextstep3
+ ;;
+ *-gould)
+ os=-sysv
+ ;;
+ *-highlevel)
+ os=-bsd
+ ;;
+ *-encore)
+ os=-bsd
+ ;;
+ *-sgi)
+ os=-irix
+ ;;
+ *-siemens)
+ os=-sysv4
+ ;;
+ *-masscomp)
+ os=-rtu
+ ;;
+ f30[01]-fujitsu | f700-fujitsu)
+ os=-uxpv
+ ;;
+ *-rom68k)
+ os=-coff
+ ;;
+ *-*bug)
+ os=-coff
+ ;;
+ *-apple)
+ os=-macos
+ ;;
+ *-atari*)
+ os=-mint
+ ;;
+ *)
+ os=-none
+ ;;
+esac
+fi
+
+# Here we handle the case where we know the os, and the CPU type, but not the
+# manufacturer. We pick the logical manufacturer.
+vendor=unknown
+case $basic_machine in
+ *-unknown)
+ case $os in
+ -riscix*)
+ vendor=acorn
+ ;;
+ -sunos*)
+ vendor=sun
+ ;;
+ -cnk*|-aix*)
+ vendor=ibm
+ ;;
+ -beos*)
+ vendor=be
+ ;;
+ -hpux*)
+ vendor=hp
+ ;;
+ -mpeix*)
+ vendor=hp
+ ;;
+ -hiux*)
+ vendor=hitachi
+ ;;
+ -unos*)
+ vendor=crds
+ ;;
+ -dgux*)
+ vendor=dg
+ ;;
+ -luna*)
+ vendor=omron
+ ;;
+ -genix*)
+ vendor=ns
+ ;;
+ -mvs* | -opened*)
+ vendor=ibm
+ ;;
+ -os400*)
+ vendor=ibm
+ ;;
+ -ptx*)
+ vendor=sequent
+ ;;
+ -tpf*)
+ vendor=ibm
+ ;;
+ -vxsim* | -vxworks* | -windiss*)
+ vendor=wrs
+ ;;
+ -aux*)
+ vendor=apple
+ ;;
+ -hms*)
+ vendor=hitachi
+ ;;
+ -mpw* | -macos*)
+ vendor=apple
+ ;;
+ -*mint | -mint[0-9]* | -*MiNT | -MiNT[0-9]*)
+ vendor=atari
+ ;;
+ -vos*)
+ vendor=stratus
+ ;;
+ esac
+ basic_machine=`echo $basic_machine | sed "s/unknown/$vendor/"`
+ ;;
+esac
+
+echo $basic_machine$os
+exit
+
+# Local variables:
+# eval: (add-hook 'write-file-hooks 'time-stamp)
+# time-stamp-start: "timestamp='"
+# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-end: "'"
+# End:
diff --git a/src/3rdparty/libpng/configure.ac b/src/3rdparty/libpng/configure.ac
new file mode 100644
index 0000000000..ff277a4d66
--- /dev/null
+++ b/src/3rdparty/libpng/configure.ac
@@ -0,0 +1,167 @@
+# configure.ac
+
+dnl Process this file with autoconf to produce a configure script.
+dnl
+dnl Minor upgrades (compatible ABI): increment the package version
+dnl (third field in two places below) and set the PNGLIB_RELEASE
+dnl variable.
+dnl
+dnl Major upgrades (incompatible ABI): increment the package major
+dnl version (second field, or first if desired), set the minor
+dnl to 0, set PNGLIB_MAJOR below *and* follow the instructions in
+dnl Makefile.am to upgrade the package name.
+
+dnl This is here to prevent earlier autoconf from being used, it
+dnl should not be necessary to regenerate configure if the time
+dnl stamps are correct
+AC_PREREQ(2.59)
+
+dnl Version number stuff here:
+
+AC_INIT([libpng], [1.5.1], [png-mng-implement@lists.sourceforge.net])
+AM_INIT_AUTOMAKE
+dnl stop configure from automagically running automake
+AM_MAINTAINER_MODE
+
+PNGLIB_VERSION=1.5.1
+PNGLIB_MAJOR=1
+PNGLIB_MINOR=5
+PNGLIB_RELEASE=1
+
+dnl End of version number stuff
+
+AC_CONFIG_SRCDIR([pngget.c])
+AM_CONFIG_HEADER(config.h)
+
+# Checks for programs.
+AC_LANG([C])
+AC_PROG_CC
+AC_PROG_LD
+AC_PROG_CPP
+AC_CHECK_TOOL(SED, sed, :)
+AC_CHECK_TOOL(AWK, awk, :)
+AC_PROG_INSTALL
+AC_PROG_LN_S
+AC_PROG_MAKE_SET
+LT_INIT([win32-dll])
+
+# On Solaris 10 and 12 CPP gets set to cc -E, however this still
+# does some input parsing. We need strict ANSI-C style tokenization,
+# check this:
+AC_REQUIRE_CPP
+AC_MSG_CHECKING([for a C preprocessor that does not parse its input])
+AC_TRY_CPP([1.5.0 16BIT],
+ [DFNCPP="$CPP"],
+ [DFNCPP=""
+ sav_CPP="$CPP"
+ for CPP in "${CC-cc} -E" "${CC-cc} -E -traditional-cpp" "/lib/cpp" "cpp"; do
+ AC_TRY_CPP([1.5.0 16BIT],
+ [DFNCPP="$CPP"]
+ [break],,)
+ done
+ CPP="$sav_CPP"])
+if test -n "$DFNCPP"; then
+ AC_MSG_RESULT([$DFNCPP])
+ AC_SUBST(DFNCPP)
+else
+ AC_MSG_FAILURE([not found], 1)
+fi
+
+# Checks for header files.
+AC_HEADER_STDC
+AC_CHECK_HEADERS([malloc.h stdlib.h string.h strings.h])
+
+# Checks for typedefs, structures, and compiler characteristics.
+AC_C_CONST
+AC_TYPE_SIZE_T
+AC_STRUCT_TM
+
+# Checks for library functions.
+AC_FUNC_STRTOD
+AC_CHECK_FUNCS([memset], , AC_ERROR([memset not found in libc]))
+AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_ERROR([cannot find pow])) )
+AC_ARG_WITH(zlib-prefix,
+ AC_HELP_STRING([--with-zlib-prefix],
+ [prefix that may have been used in installed zlib]),
+ [ZPREFIX=${withval}],
+ [ZPREFIX='z_'])
+AC_CHECK_LIB(z, zlibVersion, ,
+ AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, ,
+ AC_ERROR([zlib not installed])))
+
+
+LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG
+LIBPNG_DEFINES=$LIBPNG_DEFINES
+AC_SUBST(LIBPNG_DEFINES)
+
+AC_MSG_CHECKING([if libraries can be versioned])
+# Special case for PE/COFF platforms: ld reports
+# support for version-script, but doesn't actually
+# DO anything with it.
+case $host in
+*cygwin* | *mingw32* | *interix* )
+ have_ld_version_script=no
+ AC_MSG_RESULT(no)
+;;
+* )
+GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
+if test "$GLD"; then
+ have_ld_version_script=yes
+ AC_MSG_RESULT(yes)
+else
+ have_ld_version_script=no
+ AC_MSG_RESULT(no)
+ AC_MSG_WARN(*** You have not enabled versioned symbols.)
+fi
+;;
+esac
+
+AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
+
+if test "$have_ld_version_script" = "yes"; then
+ AC_MSG_CHECKING([for symbol prefix])
+ SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
+ | ${CPP-${CC-gcc} -E} - 2>&1 \
+ | ${EGREP-grep} "^PREFIX=" \
+ | ${SED-sed} "s:^PREFIX=::"`
+ AC_SUBST(SYMBOL_PREFIX)
+ AC_MSG_RESULT($SYMBOL_PREFIX)
+fi
+
+# Substitutions for .in files
+AC_SUBST(PNGLIB_VERSION)
+AC_SUBST(PNGLIB_MAJOR)
+AC_SUBST(PNGLIB_MINOR)
+AC_SUBST(PNGLIB_RELEASE)
+
+# Additional arguments (and substitutions)
+# Allow the pkg-config directory to be set
+AC_ARG_WITH(pkgconfigdir,
+ AC_HELP_STRING([--with-pkgconfigdir],
+ [Use the specified pkgconfig dir (default is libdir/pkgconfig)]),
+ [pkgconfigdir=${withval}],
+ [pkgconfigdir='${libdir}/pkgconfig'])
+
+AC_SUBST([pkgconfigdir])
+AC_MSG_NOTICE([pkgconfig directory is ${pkgconfigdir}])
+
+# Make the *-config binary config scripts optional
+AC_ARG_WITH(binconfigs,
+ AC_HELP_STRING([--with-binconfigs],
+ [Generate shell libpng-config scripts as well as pkg-config data]
+ [@<:@default=yes@:>@]),
+ [if test "${withval}" = no; then
+ binconfigs=
+ AC_MSG_NOTICE([libpng-config scripts will not be built])
+ else
+ binconfigs='${binconfigs}'
+ fi],
+ [binconfigs='${binconfigs}'])
+AC_SUBST([binconfigs])
+
+# Config files, substituting as above
+AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
+AC_CONFIG_FILES([libpng-config:libpng-config.in],
+ [chmod +x libpng-config])
+
+AC_OUTPUT
diff --git a/src/3rdparty/libpng/example.c b/src/3rdparty/libpng/example.c
new file mode 100644
index 0000000000..cd3682f014
--- /dev/null
+++ b/src/3rdparty/libpng/example.c
@@ -0,0 +1,843 @@
+
+#if 0 /* in case someone actually tries to compile this */
+
+/* example.c - an example of using libpng
+ * Last changed in libpng 1.5.0 [January 6, 2011]
+ * This file has been placed in the public domain by the authors.
+ * Maintained 1998-2011 Glenn Randers-Pehrson
+ * Maintained 1996, 1997 Andreas Dilger)
+ * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+/* This is an example of how to use libpng to read and write PNG files.
+ * The file libpng-manual.txt is much more verbose then this. If you have not
+ * read it, do so first. This was designed to be a starting point of an
+ * implementation. This is not officially part of libpng, is hereby placed
+ * in the public domain, and therefore does not require a copyright notice.
+ *
+ * This file does not currently compile, because it is missing certain
+ * parts, like allocating memory to hold an image. You will have to
+ * supply these parts to get it to compile. For an example of a minimal
+ * working PNG reader/writer, see pngtest.c, included in this distribution;
+ * see also the programs in the contrib directory.
+ */
+
+#include "png.h"
+
+ /* The png_jmpbuf() macro, used in error handling, became available in
+ * libpng version 1.0.6. If you want to be able to run your code with older
+ * versions of libpng, you must define the macro yourself (but only if it
+ * is not already defined by libpng!).
+ */
+
+#ifndef png_jmpbuf
+# define png_jmpbuf(png_ptr) ((png_ptr)->png_jmpbuf)
+#endif
+
+/* Check to see if a file is a PNG file using png_sig_cmp(). png_sig_cmp()
+ * returns zero if the image is a PNG and nonzero if it isn't a PNG.
+ *
+ * The function check_if_png() shown here, but not used, returns nonzero (true)
+ * if the file can be opened and is a PNG, 0 (false) otherwise.
+ *
+ * If this call is successful, and you are going to keep the file open,
+ * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
+ * you have created the png_ptr, so that libpng knows your application
+ * has read that many bytes from the start of the file. Make sure you
+ * don't call png_set_sig_bytes() with more than 8 bytes read or give it
+ * an incorrect number of bytes read, or you will either have read too
+ * many bytes (your fault), or you are telling libpng to read the wrong
+ * number of magic bytes (also your fault).
+ *
+ * Many applications already read the first 2 or 4 bytes from the start
+ * of the image to determine the file type, so it would be easiest just
+ * to pass the bytes to png_sig_cmp() or even skip that if you know
+ * you have a PNG file, and call png_set_sig_bytes().
+ */
+#define PNG_BYTES_TO_CHECK 4
+int check_if_png(char *file_name, FILE **fp)
+{
+ char buf[PNG_BYTES_TO_CHECK];
+
+ /* Open the prospective PNG file. */
+ if ((*fp = fopen(file_name, "rb")) == NULL)
+ return 0;
+
+ /* Read in some of the signature bytes */
+ if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
+ return 0;
+
+ /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
+ Return nonzero (true) if they match */
+
+ return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
+}
+
+/* Read a PNG file. You may want to return an error code if the read
+ * fails (depending upon the failure). There are two "prototypes" given
+ * here - one where we are given the filename, and we need to open the
+ * file, and the other where we are given an open file (possibly with
+ * some or all of the magic bytes read - see comments above).
+ */
+#ifdef open_file /* prototype 1 */
+void read_png(char *file_name) /* We need to open the file */
+{
+ png_structp png_ptr;
+ png_infop info_ptr;
+ unsigned int sig_read = 0;
+ png_uint_32 width, height;
+ int bit_depth, color_type, interlace_type;
+ FILE *fp;
+
+ if ((fp = fopen(file_name, "rb")) == NULL)
+ return (ERROR);
+
+#else no_open_file /* prototype 2 */
+void read_png(FILE *fp, unsigned int sig_read) /* File is already open */
+{
+ png_structp png_ptr;
+ png_infop info_ptr;
+ png_uint_32 width, height;
+ int bit_depth, color_type, interlace_type;
+#endif no_open_file /* Only use one prototype! */
+
+ /* Create and initialize the png_struct with the desired error handler
+ * functions. If you want to use the default stderr and longjump method,
+ * you can supply NULL for the last three parameters. We also supply the
+ * the compiler header file version, so that we know if the application
+ * was compiled with a compatible version of the library. REQUIRED
+ */
+ png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+ png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+
+ if (png_ptr == NULL)
+ {
+ fclose(fp);
+ return (ERROR);
+ }
+
+ /* Allocate/initialize the memory for image information. REQUIRED. */
+ info_ptr = png_create_info_struct(png_ptr);
+ if (info_ptr == NULL)
+ {
+ fclose(fp);
+ png_destroy_read_struct(&png_ptr, NULL, NULL);
+ return (ERROR);
+ }
+
+ /* Set error handling if you are using the setjmp/longjmp method (this is
+ * the normal method of doing things with libpng). REQUIRED unless you
+ * set up your own error handlers in the png_create_read_struct() earlier.
+ */
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ /* Free all of the memory associated with the png_ptr and info_ptr */
+ png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+ fclose(fp);
+ /* If we get here, we had a problem reading the file */
+ return (ERROR);
+ }
+
+ /* One of the following I/O initialization methods is REQUIRED */
+#ifdef streams /* PNG file I/O method 1 */
+ /* Set up the input control if you are using standard C streams */
+ png_init_io(png_ptr, fp);
+
+#else no_streams /* PNG file I/O method 2 */
+ /* If you are using replacement read functions, instead of calling
+ * png_init_io() here you would call:
+ */
+ png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
+ /* where user_io_ptr is a structure you want available to the callbacks */
+#endif no_streams /* Use only one I/O method! */
+
+ /* If we have already read some of the signature */
+ png_set_sig_bytes(png_ptr, sig_read);
+
+#ifdef hilevel
+ /*
+ * If you have enough memory to read in the entire image at once,
+ * and you need to specify only transforms that can be controlled
+ * with one of the PNG_TRANSFORM_* bits (this presently excludes
+ * quantizing, filling, setting background, and doing gamma
+ * adjustment), then you can read the entire image (including
+ * pixels) into the info structure with this call:
+ */
+ png_read_png(png_ptr, info_ptr, png_transforms, NULL);
+
+#else
+ /* OK, you're doing it the hard way, with the lower-level functions */
+
+ /* The call to png_read_info() gives us all of the information from the
+ * PNG file before the first IDAT (image data chunk). REQUIRED
+ */
+ png_read_info(png_ptr, info_ptr);
+
+ png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+ &interlace_type, NULL, NULL);
+
+ /* Set up the data transformations you want. Note that these are all
+ * optional. Only call them if you want/need them. Many of the
+ * transformations only work on specific types of images, and many
+ * are mutually exclusive.
+ */
+
+ /* Tell libpng to strip 16 bit/color files down to 8 bits/color */
+ png_set_strip_16(png_ptr);
+
+ /* Strip alpha bytes from the input data without combining with the
+ * background (not recommended).
+ */
+ png_set_strip_alpha(png_ptr);
+
+ /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
+ * byte into separate bytes (useful for paletted and grayscale images).
+ */
+ png_set_packing(png_ptr);
+
+ /* Change the order of packed pixels to least significant bit first
+ * (not useful if you are using png_set_packing). */
+ png_set_packswap(png_ptr);
+
+ /* Expand paletted colors into true RGB triplets */
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ png_set_palette_to_rgb(png_ptr);
+
+ /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
+ if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+ png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+ /* Expand paletted or RGB images with transparency to full alpha channels
+ * so the data will be available as RGBA quartets.
+ */
+ if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+ png_set_tRNS_to_alpha(png_ptr);
+
+ /* Set the background color to draw transparent and alpha images over.
+ * It is possible to set the red, green, and blue components directly
+ * for paletted images instead of supplying a palette index. Note that
+ * even if the PNG file supplies a background, you are not required to
+ * use it - you should use the (solid) application background if it has one.
+ */
+
+ png_color_16 my_background, *image_background;
+
+ if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+ png_set_background(png_ptr, image_background,
+ PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+ else
+ png_set_background(png_ptr, &my_background,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
+
+ /* Some suggestions as to how to get a screen gamma value
+ *
+ * Note that screen gamma is the display_exponent, which includes
+ * the CRT_exponent and any correction for viewing conditions
+ */
+ if (/* We have a user-defined screen gamma value */)
+ {
+ screen_gamma = user-defined screen_gamma;
+ }
+ /* This is one way that applications share the same screen gamma value */
+ else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
+ {
+ screen_gamma = atof(gamma_str);
+ }
+ /* If we don't have another value */
+ else
+ {
+ screen_gamma = 2.2; /* A good guess for a PC monitor in a dimly
+ lit room */
+ screen_gamma = 1.7 or 1.0; /* A good guess for Mac systems */
+ }
+
+ /* Tell libpng to handle the gamma conversion for you. The final call
+ * is a good guess for PC generated images, but it should be configurable
+ * by the user at run time by the user. It is strongly suggested that
+ * your application support gamma correction.
+ */
+
+ int intent;
+
+ if (png_get_sRGB(png_ptr, info_ptr, &intent))
+ png_set_gamma(png_ptr, screen_gamma, 0.45455);
+ else
+ {
+ double image_gamma;
+ if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
+ png_set_gamma(png_ptr, screen_gamma, image_gamma);
+ else
+ png_set_gamma(png_ptr, screen_gamma, 0.45455);
+ }
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+ /* Quantize RGB files down to 8 bit palette or reduce palettes
+ * to the number of colors available on your screen.
+ */
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ int num_palette;
+ png_colorp palette;
+
+ /* This reduces the image to the application supplied palette */
+ if (/* We have our own palette */)
+ {
+ /* An array of colors to which the image should be quantized */
+ png_color std_color_cube[MAX_SCREEN_COLORS];
+
+ png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
+ MAX_SCREEN_COLORS, NULL, 0);
+ }
+ /* This reduces the image to the palette supplied in the file */
+ else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
+ {
+ png_uint_16p histogram = NULL;
+
+ png_get_hIST(png_ptr, info_ptr, &histogram);
+
+ png_set_quantize(png_ptr, palette, num_palette,
+ max_screen_colors, histogram, 0);
+ }
+ }
+#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+
+ /* Invert monochrome files to have 0 as white and 1 as black */
+ png_set_invert_mono(png_ptr);
+
+ /* If you want to shift the pixel values from the range [0,255] or
+ * [0,65535] to the original [0,7] or [0,31], or whatever range the
+ * colors were originally in:
+ */
+ if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
+ {
+ png_color_8p sig_bit_p;
+
+ png_get_sBIT(png_ptr, info_ptr, &sig_bit_p);
+ png_set_shift(png_ptr, sig_bit_p);
+ }
+
+ /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ png_set_bgr(png_ptr);
+
+ /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
+ png_set_swap_alpha(png_ptr);
+
+ /* Swap bytes of 16 bit files to least significant byte first */
+ png_set_swap(png_ptr);
+
+ /* Add filler (or alpha) byte (before/after each RGB triplet) */
+ png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
+
+ /* Turn on interlace handling. REQUIRED if you are not using
+ * png_read_image(). To see how to handle interlacing passes,
+ * see the png_read_row() method below:
+ */
+ number_passes = png_set_interlace_handling(png_ptr);
+
+ /* Optional call to gamma correct and add the background to the palette
+ * and update info structure. REQUIRED if you are expecting libpng to
+ * update the palette for you (ie you selected such a transform above).
+ */
+ png_read_update_info(png_ptr, info_ptr);
+
+ /* Allocate the memory to hold the image using the fields of info_ptr. */
+
+ /* The easiest way to read the image: */
+ png_bytep row_pointers[height];
+
+ /* Clear the pointer array */
+ for (row = 0; row < height; row++)
+ row_pointers[row] = NULL;
+
+ for (row = 0; row < height; row++)
+ row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+ info_ptr));
+
+ /* Now it's time to read the image. One of these methods is REQUIRED */
+#ifdef entire /* Read the entire image in one go */
+ png_read_image(png_ptr, row_pointers);
+
+#else no_entire /* Read the image one or more scanlines at a time */
+ /* The other way to read images - deal with interlacing: */
+
+ for (pass = 0; pass < number_passes; pass++)
+ {
+#ifdef single /* Read the image a single row at a time */
+ for (y = 0; y < height; y++)
+ {
+ png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
+ }
+
+#else no_single /* Read the image several rows at a time */
+ for (y = 0; y < height; y += number_of_rows)
+ {
+#ifdef sparkle /* Read the image using the "sparkle" effect. */
+ png_read_rows(png_ptr, &row_pointers[y], NULL,
+ number_of_rows);
+#else no_sparkle /* Read the image using the "rectangle" effect */
+ png_read_rows(png_ptr, NULL, &row_pointers[y],
+ number_of_rows);
+#endif no_sparkle /* Use only one of these two methods */
+ }
+
+ /* If you want to display the image after every pass, do so here */
+#endif no_single /* Use only one of these two methods */
+ }
+#endif no_entire /* Use only one of these two methods */
+
+ /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
+ png_read_end(png_ptr, info_ptr);
+#endif hilevel
+
+ /* At this point you have read the entire image */
+
+ /* Clean up after the read, and free any memory allocated - REQUIRED */
+ png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+ /* Close the file */
+ fclose(fp);
+
+ /* That's it */
+ return (OK);
+}
+
+/* Progressively read a file */
+
+int
+initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
+{
+ /* Create and initialize the png_struct with the desired error handler
+ * functions. If you want to use the default stderr and longjump method,
+ * you can supply NULL for the last three parameters. We also check that
+ * the library version is compatible in case we are using dynamically
+ * linked libraries.
+ */
+ *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+ png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+
+ if (*png_ptr == NULL)
+ {
+ *info_ptr = NULL;
+ return (ERROR);
+ }
+
+ *info_ptr = png_create_info_struct(png_ptr);
+
+ if (*info_ptr == NULL)
+ {
+ png_destroy_read_struct(png_ptr, info_ptr, NULL);
+ return (ERROR);
+ }
+
+ if (setjmp(png_jmpbuf((*png_ptr))))
+ {
+ png_destroy_read_struct(png_ptr, info_ptr, NULL);
+ return (ERROR);
+ }
+
+ /* This one's new. You will need to provide all three
+ * function callbacks, even if you aren't using them all.
+ * If you aren't using all functions, you can specify NULL
+ * parameters. Even when all three functions are NULL,
+ * you need to call png_set_progressive_read_fn().
+ * These functions shouldn't be dependent on global or
+ * static variables if you are decoding several images
+ * simultaneously. You should store stream specific data
+ * in a separate struct, given as the second parameter,
+ * and retrieve the pointer from inside the callbacks using
+ * the function png_get_progressive_ptr(png_ptr).
+ */
+ png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
+ info_callback, row_callback, end_callback);
+
+ return (OK);
+}
+
+int
+process_data(png_structp *png_ptr, png_infop *info_ptr,
+ png_bytep buffer, png_uint_32 length)
+{
+ if (setjmp(png_jmpbuf((*png_ptr))))
+ {
+ /* Free the png_ptr and info_ptr memory on error */
+ png_destroy_read_struct(png_ptr, info_ptr, NULL);
+ return (ERROR);
+ }
+
+ /* This one's new also. Simply give it chunks of data as
+ * they arrive from the data stream (in order, of course).
+ * On segmented machines, don't give it any more than 64K.
+ * The library seems to run fine with sizes of 4K, although
+ * you can give it much less if necessary (I assume you can
+ * give it chunks of 1 byte, but I haven't tried with less
+ * than 256 bytes yet). When this function returns, you may
+ * want to display any rows that were generated in the row
+ * callback, if you aren't already displaying them there.
+ */
+ png_process_data(*png_ptr, *info_ptr, buffer, length);
+ return (OK);
+}
+
+info_callback(png_structp png_ptr, png_infop info)
+{
+ /* Do any setup here, including setting any of the transformations
+ * mentioned in the Reading PNG files section. For now, you _must_
+ * call either png_start_read_image() or png_read_update_info()
+ * after all the transformations are set (even if you don't set
+ * any). You may start getting rows before png_process_data()
+ * returns, so this is your last chance to prepare for that.
+ */
+}
+
+row_callback(png_structp png_ptr, png_bytep new_row,
+ png_uint_32 row_num, int pass)
+{
+ /*
+ * This function is called for every row in the image. If the
+ * image is interlaced, and you turned on the interlace handler,
+ * this function will be called for every row in every pass.
+ *
+ * In this function you will receive a pointer to new row data from
+ * libpng called new_row that is to replace a corresponding row (of
+ * the same data format) in a buffer allocated by your application.
+ *
+ * The new row data pointer "new_row" may be NULL, indicating there is
+ * no new data to be replaced (in cases of interlace loading).
+ *
+ * If new_row is not NULL then you need to call
+ * png_progressive_combine_row() to replace the corresponding row as
+ * shown below:
+ */
+
+ /* Get pointer to corresponding row in our
+ * PNG read buffer.
+ */
+ png_bytep old_row = ((png_bytep *)our_data)[row_num];
+
+ /* If both rows are allocated then copy the new row
+ * data to the corresponding row data.
+ */
+ if ((old_row != NULL) && (new_row != NULL))
+ png_progressive_combine_row(png_ptr, old_row, new_row);
+
+ /*
+ * The rows and passes are called in order, so you don't really
+ * need the row_num and pass, but I'm supplying them because it
+ * may make your life easier.
+ *
+ * For the non-NULL rows of interlaced images, you must call
+ * png_progressive_combine_row() passing in the new row and the
+ * old row, as demonstrated above. You can call this function for
+ * NULL rows (it will just return) and for non-interlaced images
+ * (it just does the png_memcpy for you) if it will make the code
+ * easier. Thus, you can just do this for all cases:
+ */
+
+ png_progressive_combine_row(png_ptr, old_row, new_row);
+
+ /* where old_row is what was displayed for previous rows. Note
+ * that the first pass (pass == 0 really) will completely cover
+ * the old row, so the rows do not have to be initialized. After
+ * the first pass (and only for interlaced images), you will have
+ * to pass the current row as new_row, and the function will combine
+ * the old row and the new row.
+ */
+}
+
+end_callback(png_structp png_ptr, png_infop info)
+{
+ /* This function is called when the whole image has been read,
+ * including any chunks after the image (up to and including
+ * the IEND). You will usually have the same info chunk as you
+ * had in the header, although some data may have been added
+ * to the comments and time fields.
+ *
+ * Most people won't do much here, perhaps setting a flag that
+ * marks the image as finished.
+ */
+}
+
+/* Write a png file */
+void write_png(char *file_name /* , ... other image information ... */)
+{
+ FILE *fp;
+ png_structp png_ptr;
+ png_infop info_ptr;
+ png_colorp palette;
+
+ /* Open the file */
+ fp = fopen(file_name, "wb");
+ if (fp == NULL)
+ return (ERROR);
+
+ /* Create and initialize the png_struct with the desired error handler
+ * functions. If you want to use the default stderr and longjump method,
+ * you can supply NULL for the last three parameters. We also check that
+ * the library version is compatible with the one used at compile time,
+ * in case we are using dynamically linked libraries. REQUIRED.
+ */
+ png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+ png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+
+ if (png_ptr == NULL)
+ {
+ fclose(fp);
+ return (ERROR);
+ }
+
+ /* Allocate/initialize the image information data. REQUIRED */
+ info_ptr = png_create_info_struct(png_ptr);
+ if (info_ptr == NULL)
+ {
+ fclose(fp);
+ png_destroy_write_struct(&png_ptr, NULL);
+ return (ERROR);
+ }
+
+ /* Set error handling. REQUIRED if you aren't supplying your own
+ * error handling functions in the png_create_write_struct() call.
+ */
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ /* If we get here, we had a problem writing the file */
+ fclose(fp);
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ return (ERROR);
+ }
+
+ /* One of the following I/O initialization functions is REQUIRED */
+
+#ifdef streams /* I/O initialization method 1 */
+ /* Set up the output control if you are using standard C streams */
+ png_init_io(png_ptr, fp);
+
+#else no_streams /* I/O initialization method 2 */
+ /* If you are using replacement write functions, instead of calling
+ * png_init_io() here you would call
+ */
+ png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
+ user_IO_flush_function);
+ /* where user_io_ptr is a structure you want available to the callbacks */
+#endif no_streams /* Only use one initialization method */
+
+#ifdef hilevel
+ /* This is the easy way. Use it if you already have all the
+ * image info living in the structure. You could "|" many
+ * PNG_TRANSFORM flags into the png_transforms integer here.
+ */
+ png_write_png(png_ptr, info_ptr, png_transforms, NULL);
+
+#else
+ /* This is the hard way */
+
+ /* Set the image information here. Width and height are up to 2^31,
+ * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
+ * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
+ * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
+ * or PNG_COLOR_TYPE_RGB_ALPHA. interlace is either PNG_INTERLACE_NONE or
+ * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
+ * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED
+ */
+ png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_???,
+ PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+ /* Set the palette if there is one. REQUIRED for indexed-color images */
+ palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
+ * png_sizeof(png_color));
+ /* ... Set palette colors ... */
+ png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
+ /* You must not free palette here, because png_set_PLTE only makes a link to
+ * the palette that you malloced. Wait until you are about to destroy
+ * the png structure.
+ */
+
+ /* Optional significant bit (sBIT) chunk */
+ png_color_8 sig_bit;
+
+ /* If we are dealing with a grayscale image then */
+ sig_bit.gray = true_bit_depth;
+
+ /* Otherwise, if we are dealing with a color image then */
+ sig_bit.red = true_red_bit_depth;
+ sig_bit.green = true_green_bit_depth;
+ sig_bit.blue = true_blue_bit_depth;
+
+ /* If the image has an alpha channel then */
+ sig_bit.alpha = true_alpha_bit_depth;
+
+ png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+
+ /* Optional gamma chunk is strongly suggested if you have any guess
+ * as to the correct gamma of the image.
+ */
+ png_set_gAMA(png_ptr, info_ptr, gamma);
+
+ /* Optionally write comments into the image */
+ text_ptr[0].key = "Title";
+ text_ptr[0].text = "Mona Lisa";
+ text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
+ text_ptr[0].itxt_length = 0;
+ text_ptr[0].lang = NULL;
+ text_ptr[0].lang_key = NULL;
+ text_ptr[1].key = "Author";
+ text_ptr[1].text = "Leonardo DaVinci";
+ text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
+ text_ptr[1].itxt_length = 0;
+ text_ptr[1].lang = NULL;
+ text_ptr[1].lang_key = NULL;
+ text_ptr[2].key = "Description";
+ text_ptr[2].text = "<long text>";
+ text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
+ text_ptr[2].itxt_length = 0;
+ text_ptr[2].lang = NULL;
+ text_ptr[2].lang_key = NULL;
+ png_set_text(png_ptr, info_ptr, text_ptr, 3);
+
+ /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */
+
+ /* Note that if sRGB is present the gAMA and cHRM chunks must be ignored
+ * on read and, if your application chooses to write them, they must
+ * be written in accordance with the sRGB profile
+ */
+
+ /* Write the file header information. REQUIRED */
+ png_write_info(png_ptr, info_ptr);
+
+ /* If you want, you can write the info in two steps, in case you need to
+ * write your private chunk ahead of PLTE:
+ *
+ * png_write_info_before_PLTE(write_ptr, write_info_ptr);
+ * write_my_chunk();
+ * png_write_info(png_ptr, info_ptr);
+ *
+ * However, given the level of known- and unknown-chunk support in 1.2.0
+ * and up, this should no longer be necessary.
+ */
+
+ /* Once we write out the header, the compression type on the text
+ * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+ * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
+ * at the end.
+ */
+
+ /* Set up the transformations you want. Note that these are
+ * all optional. Only call them if you want them.
+ */
+
+ /* Invert monochrome pixels */
+ png_set_invert_mono(png_ptr);
+
+ /* Shift the pixels up to a legal bit depth and fill in
+ * as appropriate to correctly scale the image.
+ */
+ png_set_shift(png_ptr, &sig_bit);
+
+ /* Pack pixels into bytes */
+ png_set_packing(png_ptr);
+
+ /* Swap location of alpha bytes from ARGB to RGBA */
+ png_set_swap_alpha(png_ptr);
+
+ /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
+ * RGB (4 channels -> 3 channels). The second parameter is not used.
+ */
+ png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+ /* Flip BGR pixels to RGB */
+ png_set_bgr(png_ptr);
+
+ /* Swap bytes of 16-bit files to most significant byte first */
+ png_set_swap(png_ptr);
+
+ /* Swap bits of 1, 2, 4 bit packed pixel formats */
+ png_set_packswap(png_ptr);
+
+ /* Turn on interlace handling if you are not using png_write_image() */
+ if (interlacing)
+ number_passes = png_set_interlace_handling(png_ptr);
+
+ else
+ number_passes = 1;
+
+ /* The easiest way to write the image (you may have a different memory
+ * layout, however, so choose what fits your needs best). You need to
+ * use the first method if you aren't handling interlacing yourself.
+ */
+ png_uint_32 k, height, width;
+ png_byte image[height][width*bytes_per_pixel];
+ png_bytep row_pointers[height];
+
+ if (height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
+ png_error (png_ptr, "Image is too tall to process in memory");
+
+ for (k = 0; k < height; k++)
+ row_pointers[k] = image + k*width*bytes_per_pixel;
+
+ /* One of the following output methods is REQUIRED */
+
+#ifdef entire /* Write out the entire image data in one call */
+ png_write_image(png_ptr, row_pointers);
+
+ /* The other way to write the image - deal with interlacing */
+
+#else no_entire /* Write out the image data by one or more scanlines */
+
+ /* The number of passes is either 1 for non-interlaced images,
+ * or 7 for interlaced images.
+ */
+ for (pass = 0; pass < number_passes; pass++)
+ {
+ /* Write a few rows at a time. */
+ png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);
+
+ /* If you are only writing one row at a time, this works */
+ for (y = 0; y < height; y++)
+ png_write_rows(png_ptr, &row_pointers[y], 1);
+ }
+#endif no_entire /* Use only one output method */
+
+ /* You can write optional chunks like tEXt, zTXt, and tIME at the end
+ * as well. Shouldn't be necessary in 1.2.0 and up as all the public
+ * chunks are supported and you can use png_set_unknown_chunks() to
+ * register unknown chunks into the info structure to be written out.
+ */
+
+ /* It is REQUIRED to call this to finish writing the rest of the file */
+ png_write_end(png_ptr, info_ptr);
+#endif hilevel
+
+ /* If you png_malloced a palette, free it here (don't free info_ptr->palette,
+ * as recommended in versions 1.0.5m and earlier of this example; if
+ * libpng mallocs info_ptr->palette, libpng will free it). If you
+ * allocated it with malloc() instead of png_malloc(), use free() instead
+ * of png_free().
+ */
+ png_free(png_ptr, palette);
+ palette = NULL;
+
+ /* Similarly, if you png_malloced any data that you passed in with
+ * png_set_something(), such as a hist or trans array, free it here,
+ * when you can be sure that libpng is through with it.
+ */
+ png_free(png_ptr, trans);
+ trans = NULL;
+ /* Whenever you use png_free() it is a good idea to set the pointer to
+ * NULL in case your application inadvertently tries to png_free() it
+ * again. When png_free() sees a NULL it returns without action, thus
+ * avoiding the double-free security problem.
+ */
+
+ /* Clean up after the write, and free any memory allocated */
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+
+ /* Close the file */
+ fclose(fp);
+
+ /* That's it */
+ return (OK);
+}
+
+#endif /* if 0 */
diff --git a/src/3rdparty/libpng/libpng-manual.txt b/src/3rdparty/libpng/libpng-manual.txt
new file mode 100644
index 0000000000..77adf7aec8
--- /dev/null
+++ b/src/3rdparty/libpng/libpng-manual.txt
@@ -0,0 +1,4136 @@
+libpng-manual.txt - A description on how to use and modify libpng
+
+ libpng version 1.5.1 - February 3, 2011
+ Updated and distributed by Glenn Randers-Pehrson
+ <glennrp at users.sourceforge.net>
+ Copyright (c) 1998-2011 Glenn Randers-Pehrson
+
+ This document is released under the libpng license.
+ For conditions of distribution and use, see the disclaimer
+ and license in png.h
+
+ Based on:
+
+ libpng versions 0.97, January 1998, through 1.5.1 - February 3, 2011
+ Updated and distributed by Glenn Randers-Pehrson
+ Copyright (c) 1998-2011 Glenn Randers-Pehrson
+
+ libpng 1.0 beta 6 version 0.96 May 28, 1997
+ Updated and distributed by Andreas Dilger
+ Copyright (c) 1996, 1997 Andreas Dilger
+
+ libpng 1.0 beta 2 - version 0.88 January 26, 1996
+ For conditions of distribution and use, see copyright
+ notice in png.h. Copyright (c) 1995, 1996 Guy Eric
+ Schalnat, Group 42, Inc.
+
+ Updated/rewritten per request in the libpng FAQ
+ Copyright (c) 1995, 1996 Frank J. T. Wojcik
+ December 18, 1995 & January 20, 1996
+
+I. Introduction
+
+This file describes how to use and modify the PNG reference library
+(known as libpng) for your own use. There are five sections to this
+file: introduction, structures, reading, writing, and modification and
+configuration notes for various special platforms. In addition to this
+file, example.c is a good starting point for using the library, as
+it is heavily commented and should include everything most people
+will need. We assume that libpng is already installed; see the
+INSTALL file for instructions on how to install libpng.
+
+For examples of libpng usage, see the files "example.c", "pngtest.c",
+and the files in the "contrib" directory, all of which are included in
+the libpng distribution.
+
+Libpng was written as a companion to the PNG specification, as a way
+of reducing the amount of time and effort it takes to support the PNG
+file format in application programs.
+
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2003 (E)) at
+<http://www.w3.org/TR/2003/REC-PNG-20031110/
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<http://www.libpng.org/pub/png/documents/>. It is technically equivalent
+to the PNG specification (second edition) but has some additional material.
+
+The PNG-1.0 specification is available
+as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a
+W3C Recommendation <http://www.w3.org/TR/REC.png.html>.
+
+Some additional chunks are described in the special-purpose public chunks
+documents at <http://www.libpng.org/pub/png/documents/>.
+
+Other information
+about PNG, and the latest version of libpng, can be found at the PNG home
+page, <http://www.libpng.org/pub/png/>.
+
+Most users will not have to modify the library significantly; advanced
+users may want to modify it more. All attempts were made to make it as
+complete as possible, while keeping the code easy to understand.
+Currently, this library only supports C. Support for other languages
+is being considered.
+
+Libpng has been designed to handle multiple sessions at one time,
+to be easily modifiable, to be portable to the vast majority of
+machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
+to use. The ultimate goal of libpng is to promote the acceptance of
+the PNG file format in whatever way possible. While there is still
+work to be done (see the TODO file), libpng should cover the
+majority of the needs of its users.
+
+Libpng uses zlib for its compression and decompression of PNG files.
+Further information about zlib, and the latest version of zlib, can
+be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
+The zlib compression utility is a general purpose utility that is
+useful for more than PNG files, and can be used without libpng.
+See the documentation delivered with zlib for more details.
+You can usually find the source files for the zlib utility wherever you
+find the libpng source files.
+
+Libpng is thread safe, provided the threads are using different
+instances of the structures. Each thread should have its own
+png_struct and png_info instances, and thus its own image.
+Libpng does not protect itself against two threads using the
+same instance of a structure.
+
+II. Structures
+
+There are two main structures that are important to libpng, png_struct
+and png_info. Both are internal structures that are no longer exposed
+in the libpng interface (as of libpng 1.5.0).
+
+The png_info structure is designed to provide information about the
+PNG file. At one time, the fields of png_info were intended to be
+directly accessible to the user. However, this tended to cause problems
+with applications using dynamically loaded libraries, and as a result
+a set of interface functions for png_info (the png_get_*() and png_set_*()
+functions) was developed.
+
+The png_struct structure is the object used by the library to decode a
+single image. As of 1.5.0 this structure is also not exposed.
+
+Almost all libpng APIs require a pointer to a png_struct as the first argument.
+Many (in particular the png_set and png_get APIs) also require a pointer
+to png_info as the second argument. Some application visible macros
+defined in png.h designed for basic data access (reading and writing
+integers in the PNG format) break this rule, but it's almost always safe
+to assume that a (png_struct*) has to be passed to call an API function.
+
+The png.h header file is an invaluable reference for programming with libpng.
+And while I'm on the topic, make sure you include the libpng header file:
+
+#include <png.h>
+
+Types
+
+The png.h header file defines a number of integral types used by the
+APIs. Most of these are fairly obvious; for example types corresponding
+to integers of particular sizes and types for passing color values.
+
+One exception is how non-integral numbers are handled. For application
+convenience most APIs that take such numbers have C (double) arguments,
+however internally PNG, and libpng, use 32 bit signed integers and encode
+the value by multiplying by 100,000. As of libpng 1.5.0 a convenience
+macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
+which is simply (png_int_32).
+
+All APIs that take (double) arguments also have an matching API that
+takes the corresponding fixed point integer arguments. The fixed point
+API has the same name as the floating point one with _fixed appended.
+The actual range of values permitted in the APIs is frequently less than
+the full range of (png_fixed_point) (-21474 to +21474). When APIs require
+a non-negative argument the type is recorded as png_uint_32 above. Consult
+the header file and the text below for more information.
+
+Special care must be take with sCAL chunk handling because the chunk itself
+uses non-integral values encoded as strings containing decimal floating point
+numbers. See the comments in the header file.
+
+Configuration
+
+The main header file function declarations are frequently protected by C
+preprocessing directives of the form:
+
+ #ifdef PNG_feature_SUPPORTED
+ declare-function
+ #endif
+
+The library can be built without support for these APIs, although a
+standard build will have all implemented APIs. Application programs
+should check the feature macros before using an API for maximum
+portability. From libpng 1.5.0 the feature macros set during the build
+of libpng are recorded in the header file "pnglibconf.h" and this file
+is always included by png.h.
+
+If you don't need to change the library configuration from the default skip to
+the next section ("Reading").
+
+Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
+of the build project files in the 'projects' directory simply copy
+scripts/pnglibconf.h.prebuilt to pnglibconf.h. This means that these build
+systems do not permit easy auto-configuration of the library - they only
+support the default configuration.
+
+The easiest way to make minor changes to the libpng configuration when
+auto-configuration is supported is to add definitions to the command line
+using (typically) CPPFLAGS. For example:
+
+CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
+
+will change the internal libpng math implementation for gamma correction and
+other arithmetic calculations to fixed point, avoiding the need for fast
+floating point support. The result can be seen in the generated pnglibconf.h -
+make sure it contains the changed feature macro setting.
+
+If you need to make more extensive configuration changes - more than one or two
+feature macro settings - you can either add -DPNG_USER_CONFIG to the build
+command line and put a list of feature macro settings in pngusr.h or you can set
+DFA_XTRA (a makefile variable) to a file containing the same information in the
+form of 'option' settings.
+
+A. Changing pnglibconf.h
+
+A variety of methods exist to build libpng. Not all of these support
+reconfiguration of pnglibconf.h. To reconfigure pnglibconf.h it must either be
+rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
+
+Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt and changing
+the lines defining the supported features, paying very close attention to the
+'option' information in scripts/pnglibconf.dfa that describes those features and
+their requirements. This is easy to get wrong.
+
+B. Configuration using DFA_XTRA
+
+Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
+variant such as 'nawk' or 'gawk', is available. The configure build will
+automatically find an appropriate awk and build pnglibconf.h.
+scripts/pnglibconf.mak contains a set of make rules for doing the same thing if
+configure is not used, and many of the makefiles in the scripts directory use
+this approach.
+
+When rebuilding simply write new file containing changed options and set
+DFA_XTRA to the name of this file. This causes the build to append the new file
+to the end of scripts/pnglibconf.dfa. pngusr.dfa should contain lines of the
+following forms:
+
+everything = off
+
+This turns all optional features off. Include it at the start of pngusr.dfa to
+make it easier to build a minimal configuration. You will need to turn at least
+some features on afterward to enable either reading or writing code, or both.
+
+option feature on
+option feature off
+
+Enable or disable a single feature. This will automatically enable other
+features required by a feature that is turned on or disable other features that
+require a feature which is turned off. Conflicting settings will cause an error
+message to be emitted by awk.
+
+setting feature default value
+
+Changes the default value of setting 'feature' to 'value'. There are a small
+number of settings listed at the top of pnglibconf.h, they are documented in the
+source code. Most of these values have performance implications for the library
+but most of them have no visible effect on the API. Some can also be overridden
+from the API.
+
+C. Configuration using PNG_USR_CONFIG
+
+If -DPNG_USR_CONFIG is added to the CFLAGS when pnglibconf.h is built the file
+pngusr.h will automatically be included before the options in
+scripts/pnglibconf.dfa are processed. pngusr.h should contain only macro
+definitions turning features on or off or setting settings.
+
+Apart from the global setting "everything = off" all the options listed above
+can be set using macros in pngusr.h:
+
+#define PNG_feature_SUPPORTED
+
+is equivalent to:
+
+option feature on
+
+#define PNG_NO_feature
+
+is equivalent to:
+
+option feature off
+
+#define PNG_feature value
+
+is equivalent to:
+
+setting feature default value
+
+Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
+pngusr file you supply override the contents of scripts/pnglibconf.dfa
+
+If confusing or incomprehensible behavior results it is possible to
+examine the intermediate file pnglibconf.dfn to find the full set of
+dependency information for each setting and option. Simply locate the
+feature in the file and read the C comments that precede it.
+
+III. Reading
+
+We'll now walk you through the possible functions to call when reading
+in a PNG file sequentially, briefly explaining the syntax and purpose
+of each one. See example.c and png.h for more detail. While
+progressive reading is covered in the next section, you will still
+need some of the functions discussed in this section to read a PNG
+file.
+
+Setup
+
+You will want to do the I/O initialization(*) before you get into libpng,
+so if it doesn't work, you don't have much to undo. Of course, you
+will also want to insure that you are, in fact, dealing with a PNG
+file. Libpng provides a simple check to see if a file is a PNG file.
+To use it, pass in the first 1 to 8 bytes of the file to the function
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
+
+If you are intending to keep the file pointer open for use in libpng,
+you must ensure you don't read more than 8 bytes from the beginning
+of the file, and you also have to make a call to png_set_sig_bytes_read()
+with the number of bytes you read from the beginning. Libpng will
+then only check the bytes (if any) that your program didn't read.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions. See the discussion under
+Customizing libpng.
+
+
+ FILE *fp = fopen(file_name, "rb");
+ if (!fp)
+ {
+ return (ERROR);
+ }
+
+ fread(header, 1, number, fp);
+ is_png = !png_sig_cmp(header, 0, number);
+
+ if (!is_png)
+ {
+ return (NOT_PNG);
+ }
+
+
+Next, png_struct and png_info need to be allocated and initialized. In
+order to ensure that the size of these structures is correct even with a
+dynamically linked libpng, there are functions to initialize and
+allocate the structures. We also pass the library version, optional
+pointers to error handling functions, and a pointer to a data struct for
+use by the error functions, if necessary (the pointer and functions can
+be NULL if the default error handlers are to be used). See the section
+on Changes to Libpng below regarding the old initialization functions.
+The structure allocation functions quietly return NULL if they fail to
+create the structure, so your application should check for that.
+
+ png_structp png_ptr = png_create_read_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+
+ if (!info_ptr)
+ {
+ png_destroy_read_struct(&png_ptr,
+ (png_infopp)NULL, (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ png_infop end_info = png_create_info_struct(png_ptr);
+
+ if (!end_info)
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+If you want to use your own memory allocation routines,
+use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
+png_create_read_struct_2() instead of png_create_read_struct():
+
+ png_structp png_ptr = png_create_read_struct_2
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn, (png_voidp)
+ user_mem_ptr, user_malloc_fn, user_free_fn);
+
+The error handling routines passed to png_create_read_struct()
+and the memory alloc/free routines passed to png_create_struct_2()
+are only necessary if you are not using the libpng supplied error
+handling and memory alloc/free functions.
+
+When libpng encounters an error, it expects to longjmp back
+to your routine. Therefore, you will need to call setjmp and pass
+your png_jmpbuf(png_ptr). If you read the file from different
+routines, you will need to update the jmpbuf field every time you enter
+a new routine that will call a png_*() function.
+
+See your documentation of setjmp/longjmp for your compiler for more
+information on setjmp/longjmp. See the discussion on libpng error
+handling in the Customizing Libpng section below for more information
+on the libpng error handling. If an error occurs, and libpng longjmp's
+back to your setjmp, you will want to call png_destroy_read_struct() to
+free any memory.
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ &end_info);
+ fclose(fp);
+ return (ERROR);
+ }
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the input code. The default for libpng is to
+use the C function fread(). If you use this, you will need to pass a
+valid FILE * in the function png_init_io(). Be sure that the file is
+opened in binary mode. If you wish to handle reading data in another
+way, you need not call the png_init_io() function, but you must then
+implement the libpng I/O methods discussed in the Customizing Libpng
+section below.
+
+ png_init_io(png_ptr, fp);
+
+If you had previously opened the file and read any of the signature from
+the beginning in order to see if this was a PNG file, you need to let
+libpng know that there are some bytes missing from the start of the file.
+
+ png_set_sig_bytes(png_ptr, number);
+
+You can change the zlib compression buffer size to be used while
+reading compressed data with
+
+ png_set_compression_buffer_size(png_ptr, buffer_size);
+
+where the default size is 8192 bytes. Note that the buffer size
+is changed immediately and the buffer is reallocated immediately,
+instead of setting a flag to be acted upon later.
+
+If you want CRC errors to be handled in a different manner than
+the default, use
+
+ png_set_crc_action(png_ptr, crit_action, ancil_action);
+
+The values for png_set_crc_action() say how libpng is to handle CRC errors in
+ancillary and critical chunks, and whether to use the data contained
+therein. Note that it is impossible to "discard" data in a critical
+chunk.
+
+Choices for (int) crit_action are
+ PNG_CRC_DEFAULT 0 error/quit
+ PNG_CRC_ERROR_QUIT 1 error/quit
+ PNG_CRC_WARN_USE 3 warn/use data
+ PNG_CRC_QUIET_USE 4 quiet/use data
+ PNG_CRC_NO_CHANGE 5 use the current value
+
+Choices for (int) ancil_action are
+ PNG_CRC_DEFAULT 0 error/quit
+ PNG_CRC_ERROR_QUIT 1 error/quit
+ PNG_CRC_WARN_DISCARD 2 warn/discard data
+ PNG_CRC_WARN_USE 3 warn/use data
+ PNG_CRC_QUIET_USE 4 quiet/use data
+ PNG_CRC_NO_CHANGE 5 use the current value
+
+Setting up callback code
+
+You can set up a callback function to handle any unknown chunks in the
+input stream. You must supply the function
+
+ read_chunk_callback(png_structp png_ptr,
+ png_unknown_chunkp chunk);
+ {
+ /* The unknown chunk structure contains your
+ chunk data, along with similar data for any other
+ unknown chunks: */
+
+ png_byte name[5];
+ png_byte *data;
+ png_size_t size;
+
+ /* Note that libpng has already taken care of
+ the CRC handling */
+
+ /* put your code here. Search for your chunk in the
+ unknown chunk structure, process it, and return one
+ of the following: */
+
+ return (-n); /* chunk had an error */
+ return (0); /* did not recognize */
+ return (n); /* success */
+ }
+
+(You can give your function another name that you like instead of
+"read_chunk_callback")
+
+To inform libpng about your function, use
+
+ png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
+ read_chunk_callback);
+
+This names not only the callback function, but also a user pointer that
+you can retrieve with
+
+ png_get_user_chunk_ptr(png_ptr);
+
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks will be saved when read, in case your callback function will need
+one or more of them. This behavior can be changed with the
+png_set_keep_unknown_chunks() function, described below.
+
+At this point, you can set up a callback function that will be
+called after each row has been read, which you can use to control
+a progress meter or the like. It's demonstrated in pngtest.c.
+You must supply a function
+
+ void read_row_callback(png_structp png_ptr,
+ png_uint_32 row, int pass);
+ {
+ /* put your code here */
+ }
+
+(You can give it another name that you like instead of "read_row_callback")
+
+To inform libpng about your function, use
+
+ png_set_read_status_fn(png_ptr, read_row_callback);
+
+Unknown-chunk handling
+
+Now you get to set the way the library processes unknown chunks in the
+input PNG stream. Both known and unknown chunks will be read. Normal
+behavior is that known chunks will be parsed into information in
+various info_ptr members while unknown chunks will be discarded. This
+behavior can be wasteful if your application will never use some known
+chunk types. To change this, you can call:
+
+ png_set_keep_unknown_chunks(png_ptr, keep,
+ chunk_list, num_chunks);
+ keep - 0: default unknown chunk handling
+ 1: ignore; do not keep
+ 2: keep only if safe-to-copy
+ 3: keep even if unsafe-to-copy
+
+ You can use these definitions:
+ PNG_HANDLE_CHUNK_AS_DEFAULT 0
+ PNG_HANDLE_CHUNK_NEVER 1
+ PNG_HANDLE_CHUNK_IF_SAFE 2
+ PNG_HANDLE_CHUNK_ALWAYS 3
+
+ chunk_list - list of chunks affected (a byte string,
+ five bytes per chunk, NULL or '\0' if
+ num_chunks is 0)
+
+ num_chunks - number of chunks affected; if 0, all
+ unknown chunks are affected. If nonzero,
+ only the chunks in the list are affected
+
+Unknown chunks declared in this way will be saved as raw data onto a
+list of png_unknown_chunk structures. If a chunk that is normally
+known to libpng is named in the list, it will be handled as unknown,
+according to the "keep" directive. If a chunk is named in successive
+instances of png_set_keep_unknown_chunks(), the final instance will
+take precedence. The IHDR and IEND chunks should not be named in
+chunk_list; if they are, libpng will process them normally anyway.
+
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+ png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'};
+
+ #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+ png_byte unused_chunks[]=
+ {
+ 104, 73, 83, 84, (png_byte) '\0', /* hIST */
+ 105, 84, 88, 116, (png_byte) '\0', /* iTXt */
+ 112, 67, 65, 76, (png_byte) '\0', /* pCAL */
+ 115, 67, 65, 76, (png_byte) '\0', /* sCAL */
+ 115, 80, 76, 84, (png_byte) '\0', /* sPLT */
+ 116, 73, 77, 69, (png_byte) '\0', /* tIME */
+ };
+ #endif
+
+ ...
+
+ #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+ /* ignore all unknown chunks: */
+ png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+
+ /* except for vpAg: */
+ png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+
+ /* also ignore unused known chunks: */
+ png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+ (int)sizeof(unused_chunks)/5);
+ #endif
+
+User limits
+
+The PNG specification allows the width and height of an image to be as
+large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
+Since very few applications really need to process such large images,
+we have imposed an arbitrary 1-million limit on rows and columns.
+Larger images will be rejected immediately with a png_error() call. If
+you wish to override this limit, you can use
+
+ png_set_user_limits(png_ptr, width_max, height_max);
+
+to set your own limits, or use width_max = height_max = 0x7fffffffL
+to allow all valid dimensions (libpng may reject some very large images
+anyway because of potential buffer overflow conditions).
+
+You should put this statement after you create the PNG structure and
+before calling png_read_info(), png_read_png(), or png_process_data().
+If you need to retrieve the limits that are being applied, use
+
+ width_max = png_get_user_width_max(png_ptr);
+ height_max = png_get_user_height_max(png_ptr);
+
+The PNG specification sets no limit on the number of ancillary chunks
+allowed in a PNG datastream. You can impose a limit on the total number
+of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with
+
+ png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
+
+where 0x7fffffffL means unlimited. You can retrieve this limit with
+
+ chunk_cache_max = png_get_chunk_cache_max(png_ptr);
+
+This limit also applies to the number of buffers that can be allocated
+by png_decompress_chunk() while decompressing iTXt, zTXt, and iCCP chunks.
+
+You can also set a limit on the amount of memory that a compressed chunk
+other than IDAT can occupy, with
+
+ png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
+
+and you can retrieve the limit with
+
+ chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
+
+Any chunks that would cause either of these limits to be exceeded will
+be ignored.
+
+The high-level read interface
+
+At this point there are two ways to proceed; through the high-level
+read interface, or through a sequence of low-level read operations.
+You can use the high-level interface if (a) you are willing to read
+the entire image into memory, and (b) the input transformations
+you want to do are limited to the following set:
+
+ PNG_TRANSFORM_IDENTITY No transformation
+ PNG_TRANSFORM_STRIP_16 Strip 16-bit samples to
+ 8 bits
+ PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
+ PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit
+ samples to bytes
+ PNG_TRANSFORM_PACKSWAP Change order of packed
+ pixels to LSB first
+ PNG_TRANSFORM_EXPAND Perform set_expand()
+ PNG_TRANSFORM_INVERT_MONO Invert monochrome images
+ PNG_TRANSFORM_SHIFT Normalize pixels to the
+ sBIT depth
+ PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
+ to BGRA
+ PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
+ to AG
+ PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
+ to transparency
+ PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
+ PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples
+ to RGB (or GA to RGBA)
+
+(This excludes setting a background color, doing gamma transformation,
+quantizing, and setting filler.) If this is the case, simply do this:
+
+ png_read_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some
+set of transformation flags. This call is equivalent to png_read_info(),
+followed the set of transformations indicated by the transform mask,
+then png_read_image(), and finally png_read_end().
+
+(The final parameter of this call is not yet used. Someday it might point
+to transformation parameters required by some future input transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+
+After you have called png_read_png(), you can retrieve the image data
+with
+
+ row_pointers = png_get_rows(png_ptr, info_ptr);
+
+where row_pointers is an array of pointers to the pixel data for each row:
+
+ png_bytep row_pointers[height];
+
+If you know your image size and pixel size ahead of time, you can allocate
+row_pointers prior to calling png_read_png() with
+
+ if (height > PNG_UINT_32_MAX/png_sizeof(png_byte))
+ png_error (png_ptr,
+ "Image is too tall to process in memory");
+
+ if (width > PNG_UINT_32_MAX/pixel_size)
+ png_error (png_ptr,
+ "Image is too wide to process in memory");
+
+ row_pointers = png_malloc(png_ptr,
+ height*png_sizeof(png_bytep));
+
+ for (int i=0; i<height, i++)
+ row_pointers[i]=NULL; /* security precaution */
+
+ for (int i=0; i<height, i++)
+ row_pointers[i]=png_malloc(png_ptr,
+ width*pixel_size);
+
+ png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+Alternatively you could allocate your image in one big block and define
+row_pointers[i] to point into the proper places in your block.
+
+If you use png_set_rows(), the application is responsible for freeing
+row_pointers (and row_pointers[i], if they were separately allocated).
+
+If you don't allocate row_pointers ahead of time, png_read_png() will
+do it, and it'll be free'ed by libpng when you call png_destroy_*().
+
+The low-level read interface
+
+If you are going the low-level route, you are now ready to read all
+the file information up to the actual image data. You do this with a
+call to png_read_info().
+
+ png_read_info(png_ptr, info_ptr);
+
+This will process all chunks up to but not including the image data.
+
+Querying the info structure
+
+Functions are used to get the information from the info_ptr once it
+has been read. Note that these fields may not be completely filled
+in until png_read_end() has read the chunk data following the image.
+
+ png_get_IHDR(png_ptr, info_ptr, &width, &height,
+ &bit_depth, &color_type, &interlace_type,
+ &compression_type, &filter_method);
+
+ width - holds the width of the image
+ in pixels (up to 2^31).
+
+ height - holds the height of the image
+ in pixels (up to 2^31).
+
+ bit_depth - holds the bit depth of one of the
+ image channels. (valid values are
+ 1, 2, 4, 8, 16 and depend also on
+ the color_type. See also
+ significant bits (sBIT) below).
+
+ color_type - describes which color/alpha channels
+ are present.
+ PNG_COLOR_TYPE_GRAY
+ (bit depths 1, 2, 4, 8, 16)
+ PNG_COLOR_TYPE_GRAY_ALPHA
+ (bit depths 8, 16)
+ PNG_COLOR_TYPE_PALETTE
+ (bit depths 1, 2, 4, 8)
+ PNG_COLOR_TYPE_RGB
+ (bit_depths 8, 16)
+ PNG_COLOR_TYPE_RGB_ALPHA
+ (bit_depths 8, 16)
+
+ PNG_COLOR_MASK_PALETTE
+ PNG_COLOR_MASK_COLOR
+ PNG_COLOR_MASK_ALPHA
+
+ interlace_type - (PNG_INTERLACE_NONE or
+ PNG_INTERLACE_ADAM7)
+
+ compression_type - (must be PNG_COMPRESSION_TYPE_BASE
+ for PNG 1.0)
+
+ filter_method - (must be PNG_FILTER_TYPE_BASE
+ for PNG 1.0, and can also be
+ PNG_INTRAPIXEL_DIFFERENCING if
+ the PNG datastream is embedded in
+ a MNG-1.0 datastream)
+
+ Any or all of interlace_type, compression_type, or
+ filter_method can be NULL if you are
+ not interested in their values.
+
+ Note that png_get_IHDR() returns 32-bit data into
+ the application's width and height variables.
+ This is an unsafe situation if these are 16-bit
+ variables. In such situations, the
+ png_get_image_width() and png_get_image_height()
+ functions described below are safer.
+
+ width = png_get_image_width(png_ptr,
+ info_ptr);
+
+ height = png_get_image_height(png_ptr,
+ info_ptr);
+
+ bit_depth = png_get_bit_depth(png_ptr,
+ info_ptr);
+
+ color_type = png_get_color_type(png_ptr,
+ info_ptr);
+
+ interlace_type = png_get_interlace_type(png_ptr,
+ info_ptr);
+
+ compression_type = png_get_compression_type(png_ptr,
+ info_ptr);
+
+ filter_method = png_get_filter_type(png_ptr,
+ info_ptr);
+
+ channels = png_get_channels(png_ptr, info_ptr);
+
+ channels - number of channels of info for the
+ color type (valid values are 1 (GRAY,
+ PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
+ 4 (RGB_ALPHA or RGB + filler byte))
+
+ rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+ rowbytes - number of bytes needed to hold a row
+
+ signature = png_get_signature(png_ptr, info_ptr);
+
+ signature - holds the signature read from the
+ file (if any). The data is kept in
+ the same offset it would be if the
+ whole signature were read (i.e. if an
+ application had already read in 4
+ bytes of signature before starting
+ libpng, the remaining 4 bytes would
+ be in signature[4] through signature[7]
+ (see png_set_sig_bytes())).
+
+These are also important, but their validity depends on whether the chunk
+has been read. The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
+png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
+data has been read, or zero if it is missing. The parameters to the
+png_get_<chunk> are set directly if they are simple data types, or a
+pointer into the info_ptr is returned for any complex types.
+
+ png_get_PLTE(png_ptr, info_ptr, &palette,
+ &num_palette);
+
+ palette - the palette for the file
+ (array of png_color)
+
+ num_palette - number of entries in the palette
+
+ png_get_gAMA(png_ptr, info_ptr, &file_gamma);
+ png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
+
+ file_gamma - the gamma at which the file is
+ written (PNG_INFO_gAMA)
+
+ int_file_gamma - 100,000 times the gamma at which the
+ file is written
+
+ png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
+
+ file_srgb_intent - the rendering intent (PNG_INFO_sRGB)
+ The presence of the sRGB chunk
+ means that the pixel data is in the
+ sRGB color space. This chunk also
+ implies specific values of gAMA and
+ cHRM.
+
+ png_get_iCCP(png_ptr, info_ptr, &name,
+ &compression_type, &profile, &proflen);
+
+ name - The profile name.
+
+ compression_type - The compression type; always
+ PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+ You may give NULL to this argument to
+ ignore it.
+
+ profile - International Color Consortium color
+ profile data. May contain NULs.
+
+ proflen - length of profile data in bytes.
+
+ png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+
+ sig_bit - the number of significant bits for
+ (PNG_INFO_sBIT) each of the gray,
+ red, green, and blue channels,
+ whichever are appropriate for the
+ given color type (png_color_16)
+
+ png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
+ &num_trans, &trans_color);
+
+ trans_alpha - array of alpha (transparency)
+ entries for palette (PNG_INFO_tRNS)
+
+ num_trans - number of transparent entries
+ (PNG_INFO_tRNS)
+
+ trans_color - graylevel or color sample values of
+ the single transparent color for
+ non-paletted images (PNG_INFO_tRNS)
+
+ png_get_hIST(png_ptr, info_ptr, &hist);
+ (PNG_INFO_hIST)
+
+ hist - histogram of palette (array of
+ png_uint_16)
+
+ png_get_tIME(png_ptr, info_ptr, &mod_time);
+
+ mod_time - time image was last modified
+ (PNG_VALID_tIME)
+
+ png_get_bKGD(png_ptr, info_ptr, &background);
+
+ background - background color (PNG_VALID_bKGD)
+ valid 16-bit red, green and blue
+ values, regardless of color_type
+
+ num_comments = png_get_text(png_ptr, info_ptr,
+ &text_ptr, &num_text);
+
+ num_comments - number of comments
+
+ text_ptr - array of png_text holding image
+ comments
+
+ text_ptr[i].compression - type of compression used
+ on "text" PNG_TEXT_COMPRESSION_NONE
+ PNG_TEXT_COMPRESSION_zTXt
+ PNG_ITXT_COMPRESSION_NONE
+ PNG_ITXT_COMPRESSION_zTXt
+
+ text_ptr[i].key - keyword for comment. Must contain
+ 1-79 characters.
+
+ text_ptr[i].text - text comments for current
+ keyword. Can be empty.
+
+ text_ptr[i].text_length - length of text string,
+ after decompression, 0 for iTXt
+
+ text_ptr[i].itxt_length - length of itxt string,
+ after decompression, 0 for tEXt/zTXt
+
+ text_ptr[i].lang - language of comment (empty
+ string for unknown).
+
+ text_ptr[i].lang_key - keyword in UTF-8
+ (empty string for unknown).
+
+ Note that the itxt_length, lang, and lang_key
+ members of the text_ptr structure only exist
+ when the library is built with iTXt chunk support.
+
+ num_text - number of comments (same as
+ num_comments; you can put NULL here
+ to avoid the duplication)
+
+ Note while png_set_text() will accept text, language,
+ and translated keywords that can be NULL pointers, the
+ structure returned by png_get_text will always contain
+ regular zero-terminated C strings. They might be
+ empty strings but they will never be NULL pointers.
+
+ num_spalettes = png_get_sPLT(png_ptr, info_ptr,
+ &palette_ptr);
+
+ num_spalettes - number of sPLT chunks read.
+
+ palette_ptr - array of palette structures holding
+ contents of one or more sPLT chunks
+ read.
+
+ png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
+ &unit_type);
+
+ offset_x - positive offset from the left edge
+ of the screen
+
+ offset_y - positive offset from the top edge
+ of the screen
+
+ unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+ png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
+ &unit_type);
+
+ res_x - pixels/unit physical resolution in
+ x direction
+
+ res_y - pixels/unit physical resolution in
+ x direction
+
+ unit_type - PNG_RESOLUTION_UNKNOWN,
+ PNG_RESOLUTION_METER
+
+ png_get_sCAL(png_ptr, info_ptr, &unit, &width,
+ &height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are doubles)
+
+ png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
+ &height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are strings like "2.54")
+
+ num_unknown_chunks = png_get_unknown_chunks(png_ptr,
+ info_ptr, &unknowns)
+
+ unknowns - array of png_unknown_chunk
+ structures holding unknown chunks
+
+ unknowns[i].name - name of unknown chunk
+
+ unknowns[i].data - data of unknown chunk
+
+ unknowns[i].size - size of unknown chunk's data
+
+ unknowns[i].location - position of chunk in file
+
+ The value of "i" corresponds to the order in which the
+ chunks were read from the PNG file or inserted with the
+ png_set_unknown_chunks() function.
+
+The data from the pHYs chunk can be retrieved in several convenient
+forms:
+
+ res_x = png_get_x_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_y = png_get_y_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_x_and_y = png_get_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_x = png_get_x_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ res_y = png_get_y_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ res_x_and_y = png_get_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
+ info_ptr)
+
+ Each of these returns 0 [signifying "unknown"] if
+ the data is not present or if res_x is 0;
+ res_x_and_y is 0 if res_x != res_y
+
+ Note that because of the way the resolutions are
+ stored internally, the inch conversions won't
+ come out to exactly even number. For example,
+ 72 dpi is stored as 0.28346 pixels/meter, and
+ when this is retrieved it is 71.9988 dpi, so
+ be sure to round the returned value appropriately
+ if you want to display a reasonable-looking result.
+
+The data from the oFFs chunk can be retrieved in several convenient
+forms:
+
+ x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
+
+ y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
+
+ x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
+
+ y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
+
+ Each of these returns 0 [signifying "unknown" if both
+ x and y are 0] if the data is not present or if the
+ chunk is present but the unit is the pixel. The
+ remark about inexact inch conversions applies here
+ as well, because a value in inches can't always be
+ converted to microns and back without some loss
+ of precision.
+
+For more information, see the png_info definition in png.h and the
+PNG specification for chunk contents. Be careful with trusting
+rowbytes, as some of the transformations could increase the space
+needed to hold a row (expand, filler, gray_to_rgb, etc.).
+See png_read_update_info(), below.
+
+A quick word about text_ptr and num_text. PNG stores comments in
+keyword/text pairs, one pair per chunk, with no limit on the number
+of text chunks, and a 2^31 byte limit on their size. While there are
+suggested keywords, there is no requirement to restrict the use to these
+strings. It is strongly suggested that keywords and text be sensible
+to humans (that's the point), so don't use abbreviations. Non-printing
+symbols are not allowed. See the PNG specification for more details.
+There is also no requirement to have text after the keyword.
+
+Keywords should be limited to 79 Latin-1 characters without leading or
+trailing spaces, but non-consecutive spaces are allowed within the
+keyword. It is possible to have the same keyword any number of times.
+The text_ptr is an array of png_text structures, each holding a
+pointer to a language string, a pointer to a keyword and a pointer to
+a text string. The text string, language code, and translated
+keyword may be empty or NULL pointers. The keyword/text
+pairs are put into the array in the order that they are received.
+However, some or all of the text chunks may be after the image, so, to
+make sure you have read all the text chunks, don't mess with these
+until after you read the stuff after the image. This will be
+mentioned again below in the discussion that goes with png_read_end().
+
+Input transformations
+
+After you've read the header information, you can set up the library
+to handle any special transformations of the image data. The various
+ways to transform the data will be described in the order that they
+should occur. This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths. Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data. For example, don't swap red and blue on grayscale data.
+
+The colors used for the background and transparency values should be
+supplied in the same format/depth as the current image data. They
+are stored in the same format/depth as the image data in a bKGD or tRNS
+chunk, so this is what libpng expects for this data. The colors are
+transformed to keep in sync with the image data when an application
+calls the png_read_update_info() routine (see below).
+
+Data will be decoded into the supplied row buffers packed into bytes
+unless the library has been told to transform it into another format.
+For example, 4 bit/pixel paletted or grayscale data will be returned
+2 pixels/byte with the leftmost pixel in the high-order bits of the
+byte, unless png_set_packing() is called. 8-bit RGB data will be stored
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_strip_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert filler bytes, either before or
+after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
+be modified with
+png_set_filler(), png_set_add_alpha(), or png_set_strip_16().
+
+The following code transforms grayscale images of less than 8 to 8 bits,
+changes paletted images to RGB, and adds a full alpha channel if there is
+transparency information in a tRNS chunk. This is most useful on
+grayscale images with bit depths of 2 or 4 or if there is a multiple-image
+viewing application that wishes to treat all images in the same way.
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ png_set_palette_to_rgb(png_ptr);
+
+ if (color_type == PNG_COLOR_TYPE_GRAY &&
+ bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+ if (png_get_valid(png_ptr, info_ptr,
+ PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
+
+These three functions are actually aliases for png_set_expand(), added
+in libpng version 1.0.4, with the function names expanded to improve code
+readability. In some future version they may actually do different
+things.
+
+As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
+added. It expands the sample depth without changing tRNS to alpha.
+
+As of libpng version 1.5.1, not all possible expansions are supported.
+
+In the following table, the 01 means grayscale with depth<8, 31 means
+indexed with depth<8, other numerals represent the color type, "T" means
+the tRNS chunk is present, A means an alpha channel is present, and O
+means tRNS or alpha is present but all pixels in the image are opaque.
+
+ FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O
+ TO
+ 01 -
+ 31 -
+ 0 1 -
+ 0T -
+ 0O -
+ 2 GX -
+ 2T -
+ 2O -
+ 3 1 -
+ 3T -
+ 3O -
+ 4A T -
+ 4O -
+ 6A GX TX TX -
+ 6O GX TX -
+
+Within the matrix,
+ "-" means the transformation is not supported.
+ "X" means the transformation is obtained by png_set_expand().
+ "1" means the transformation is obtained by
+ png_set_expand_gray_1_2_4_to_8
+ "G" means the transformation is obtained by
+ png_set_gray_to_rgb().
+ "P" means the transformation is obtained by
+ png_set_expand_palette_to_rgb().
+ "T" means the transformation is obtained by
+ png_set_tRNS_to_alpha().
+
+PNG can have files with 16 bits per channel. If you only can handle
+8 bits per channel, this will strip the pixels down to 8 bit.
+
+ if (bit_depth == 16)
+ png_set_strip_16(png_ptr);
+
+If, for some reason, you don't need the alpha channel on an image,
+and you want to remove it rather than combining it with the background
+(but the image author certainly had in mind that you *would* combine
+it with the background, so that's what you should probably do):
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ png_set_strip_alpha(png_ptr);
+
+In PNG files, the alpha channel in an image
+is the level of opacity. If you need the alpha channel in an image to
+be the level of transparency instead of opacity, you can invert the
+alpha channel (or the tRNS chunk data) after it's read, so that 0 is
+fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
+images) is fully transparent, with
+
+ png_set_invert_alpha(png_ptr);
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit
+files. This code expands to 1 pixel per byte without changing the
+values of the pixels:
+
+ if (bit_depth < 8)
+ png_set_packing(png_ptr);
+
+PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels
+stored in a PNG image have been "scaled" or "shifted" up to the next
+higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
+to 8 bits/sample in the range [0, 255]). However, it is also possible
+to convert the PNG pixel data back to the original bit depth of the
+image. This call reduces the pixels back down to the original bit depth:
+
+ png_color_8p sig_bit;
+
+ if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+ png_set_shift(png_ptr, sig_bit);
+
+PNG files store 3-color pixels in red, green, blue order. This code
+changes the storage of the pixels to blue, green, red:
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_bgr(png_ptr);
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
+into 4 or 8 bytes for windowing systems that need them in this format:
+
+ if (color_type == PNG_COLOR_TYPE_RGB)
+ png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
+
+where "filler" is the 8 or 16-bit number to fill with, and the location is
+either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
+you want the filler before the RGB or after. This transformation
+does not affect images that already have full alpha channels. To add an
+opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
+will generate RGBA pixels.
+
+Note that png_set_filler() does not change the color type. If you want
+to do that, you can add a true alpha channel with
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_GRAY)
+ png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+This function was added in libpng-1.2.7.
+
+If you are reading an image with an alpha channel, and you need the
+data as ARGB instead of the normal PNG format RGBA:
+
+ if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_swap_alpha(png_ptr);
+
+For some uses, you may want a grayscale image to be represented as
+RGB. This code will do that conversion:
+
+ if (color_type == PNG_COLOR_TYPE_GRAY ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_gray_to_rgb(png_ptr);
+
+Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
+with alpha.
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_rgb_to_gray_fixed(png_ptr, error_action,
+ int red_weight, int green_weight);
+
+ error_action = 1: silently do the conversion
+
+ error_action = 2: issue a warning if the original
+ image has any pixel where
+ red != green or red != blue
+
+ error_action = 3: issue an error and abort the
+ conversion if the original
+ image has any pixel where
+ red != green or red != blue
+
+ red_weight: weight of red component times 100000
+
+ green_weight: weight of green component times 100000
+ If either weight is negative, default
+ weights (21268, 71514) are used.
+
+If you have set error_action = 1 or 2, you can
+later check whether the image really was gray, after processing
+the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
+It will return a png_byte that is zero if the image was gray or
+1 if there were any non-gray pixels. bKGD and sBIT data
+will be silently converted to grayscale, using the green channel
+data, regardless of the error_action setting.
+
+With red_weight+green_weight<=100000,
+the normalized graylevel is computed:
+
+ int rw = red_weight * 65536;
+ int gw = green_weight * 65536;
+ int bw = 65536 - (rw + gw);
+ gray = (rw*red + gw*green + bw*blue)/65536;
+
+The default values approximate those recommended in the Charles
+Poynton's Color FAQ, <http://www.inforamp.net/~poynton/>
+Copyright (c) 1998-01-04 Charles Poynton <poynton at inforamp.net>
+
+ Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+
+Libpng approximates this with integers scaled by 32768:
+
+ Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
+The calculation is done in a linear colorspace, if the image gamma
+can be determined.
+
+If you have a grayscale and you are using png_set_expand_depth(),
+png_set_expand(), or png_set_gray_to_rgb to change to truecolor or to
+a higher bit-depth, you must either supply the background color as a gray
+value at the original file bit-depth (need_expand = 1) or else supply the
+background color as an RGB triplet at the final, expanded bit depth
+(need_expand = 0). Similarly, if you are reading a paletted image, you
+must either supply the background color as a palette index (need_expand = 1)
+or as an RGB triplet that may or may not be in the palette (need_expand = 0).
+
+ png_color_16 my_background;
+ png_color_16p image_background;
+
+ if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+ png_set_background(png_ptr, image_background,
+ PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+ else
+ png_set_background(png_ptr, &my_background,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
+
+The png_set_background() function tells libpng to composite images
+with alpha or simple transparency against the supplied background
+color. If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page). You
+need to tell libpng whether the color is in the gamma space of the
+display (PNG_BACKGROUND_GAMMA_SCREEN for colors you supply), the file
+(PNG_BACKGROUND_GAMMA_FILE for colors from the bKGD chunk), or one
+that is neither of these gammas (PNG_BACKGROUND_GAMMA_UNIQUE - I don't
+know why anyone would use this, but it's here).
+
+To properly display PNG images on any kind of system, the application needs
+to know what the display gamma is. Ideally, the user will know this, and
+the application will allow them to set it. One method of allowing the user
+to set the display gamma separately for each system is to check for a
+SCREEN_GAMMA or DISPLAY_GAMMA environment variable, which will hopefully be
+correctly set.
+
+Note that display_gamma is the overall gamma correction required to produce
+pleasing results, which depends on the lighting conditions in the surrounding
+environment. In a dim or brightly lit room, no compensation other than
+the physical gamma exponent of the monitor is needed, while in a dark room
+a slightly smaller exponent is better.
+
+ double gamma, screen_gamma;
+
+ if (/* We have a user-defined screen
+ gamma value */)
+ {
+ screen_gamma = user_defined_screen_gamma;
+ }
+
+ /* One way that applications can share the same
+ screen gamma value */
+ else if ((gamma_str = getenv("SCREEN_GAMMA"))
+ != NULL)
+ {
+ screen_gamma = (double)atof(gamma_str);
+ }
+
+ /* If we don't have another value */
+ else
+ {
+ screen_gamma = 2.2; /* A good guess for a
+ PC monitor in a bright office or a dim room */
+
+ screen_gamma = 2.0; /* A good guess for a
+ PC monitor in a dark room */
+
+ screen_gamma = 1.7 or 1.0; /* A good
+ guess for Mac systems */
+ }
+
+The functions png_set_gamma() and its fixed point equivalent
+png_set_gamma_fixed() handle gamma transformations of the data.
+Pass both the file gamma and the current screen_gamma. If the file does
+not have a gamma value, you can pass one anyway if you have an idea what
+it is (usually 0.45455 is a good guess for GIF images on PCs). Note
+that file gammas are inverted from screen gammas. See the discussions
+on gamma in the PNG specification for an excellent description of what
+gamma is, and why all applications should support it. It is strongly
+recommended that PNG viewers support gamma correction.
+
+ if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
+ png_set_gamma(png_ptr, screen_gamma, file_gamma);
+
+ else
+ png_set_gamma(png_ptr, screen_gamma, 0.45455);
+
+If you need to reduce an RGB file to a paletted file, or if a paletted
+file has more entries then will fit on your screen, png_set_quantize()
+will do that. Note that this is a simple match quantization that merely
+finds the closest color available. This should work fairly well with
+optimized palettes, but fairly badly with linear color cubes. If you
+pass a palette that is larger then maximum_colors, the file will
+reduce the number of colors in the palette so it will fit into
+maximum_colors. If there is a histogram, it will use it to make
+more intelligent choices when reducing the palette. If there is no
+histogram, it may not do as good a job.
+
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ if (png_get_valid(png_ptr, info_ptr,
+ PNG_INFO_PLTE))
+ {
+ png_uint_16p histogram = NULL;
+
+ png_get_hIST(png_ptr, info_ptr,
+ &histogram);
+ png_set_quantize(png_ptr, palette, num_palette,
+ max_screen_colors, histogram, 1);
+ }
+
+ else
+ {
+ png_color std_color_cube[MAX_SCREEN_COLORS] =
+ { ... colors ... };
+
+ png_set_quantize(png_ptr, std_color_cube,
+ MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
+ NULL,0);
+ }
+ }
+
+PNG files describe monochrome as black being zero and white being one.
+The following code will reverse this (make black be one and white be
+zero):
+
+ if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
+ png_set_invert_mono(png_ptr);
+
+This function can also be used to invert grayscale and gray-alpha images:
+
+ if (color_type == PNG_COLOR_TYPE_GRAY ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_invert_mono(png_ptr);
+
+PNG files store 16 bit pixels in network byte order (big-endian,
+ie. most significant bits first). This code changes the storage to the
+other way (little-endian, i.e. least significant bits first, the
+way PCs store them):
+
+ if (bit_depth == 16)
+ png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+ if (bit_depth < 8)
+ png_set_packswap(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs. This is done by setting a callback
+with
+
+ png_set_read_user_transform_fn(png_ptr,
+ read_transform_fn);
+
+You must supply the function
+
+ void read_transform_fn(png_structp png_ptr, row_info_ptr
+ row_info, png_bytep data)
+
+See pngtest.c for a working example. Your function will be called
+after all of the other transformations have been processed. Take care with
+interlaced images if you do the interlace yourself - the width of the row is the
+width in 'row_info', not the overall image width.
+
+If supported libpng provides two information routines that you can use to find
+where you are in processing the image:
+
+ png_get_current_pass_number(png_structp png_ptr);
+ png_get_current_row_number(png_structp png_ptr);
+
+Don't try using these outside a transform callback - firstly they are only
+supported if user transforms are supported, secondly they may well return
+unexpected results unless the row is actually being processed at the moment they
+are called.
+
+You can also set up a pointer to a user structure for use by your
+callback function, and you can inform libpng that your transform
+function will change the number of channels or bit depth with the
+function
+
+ png_set_user_transform_info(png_ptr, user_ptr,
+ user_depth, user_channels);
+
+The user's application, not libpng, is responsible for allocating and
+freeing any memory required for the user structure.
+
+You can retrieve the pointer via the function
+png_get_user_transform_ptr(). For example:
+
+ voidp read_user_transform_ptr =
+ png_get_user_transform_ptr(png_ptr);
+
+The last thing to handle is interlacing; this is covered in detail below,
+but you must call the function here if you want libpng to handle expansion
+of the interlaced image.
+
+ number_of_passes = png_set_interlace_handling(png_ptr);
+
+After setting the transformations, libpng can update your png_info
+structure to reflect any transformations you've requested with this
+call. This is most useful to update the info structure's rowbytes
+field so you can use it to allocate your image memory. This function
+will also update your palette with the correct screen_gamma and
+background if these have been given with the calls above.
+
+ png_read_update_info(png_ptr, info_ptr);
+
+After you call png_read_update_info(), you can allocate any
+memory you need to hold the image. The row data is simply
+raw byte data for all forms of images. As the actual allocation
+varies among applications, no example will be given. If you
+are allocating one large chunk, you will need to build an
+array of pointers to each row, as it will be needed for some
+of the functions below.
+
+Remember: Before you call png_read_update_info(), the png_get_
+functions return the values corresponding to the original PNG image.
+After you call png_read_update_info the values refer to the image
+that libpng will output. Consequently you must call all the png_set_
+functions before you call png_read_update_info(). This is particularly
+important for png_set_interlace_handling() - if you are going to call
+png_read_update_info() you must call png_set_interlace_handling() before
+it unless you want to receive interlaced output.
+
+Reading image data
+
+After you've allocated memory, you can read the image data.
+The simplest way to do this is in one function call. If you are
+allocating enough memory to hold the whole image, you can just
+call png_read_image() and libpng will read in all the image data
+and put it in the memory area supplied. You will need to pass in
+an array of pointers to each row.
+
+This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() (unless you call
+png_read_update_info()) or call this function multiple times, or any
+of that other stuff necessary with png_read_rows().
+
+ png_read_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+ png_bytep row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to read in the whole image at once, you can
+use png_read_rows() instead. If there is no interlacing (check
+interlace_type == PNG_INTERLACE_NONE), this is simple:
+
+ png_read_rows(png_ptr, row_pointers, NULL,
+ number_of_rows);
+
+where row_pointers is the same as in the png_read_image() call.
+
+If you are doing this just one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+ png_bytep row_pointer = row;
+ png_read_row(png_ptr, row_pointer, NULL);
+
+If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
+get somewhat harder. The only current (PNG Specification version 1.2)
+interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
+a somewhat complicated 2D interlace scheme, known as Adam7, that
+breaks down an image into seven smaller images of varying size, based
+on an 8x8 grid. This number is defined (from libpng 1.5) as
+PNG_INTERLACE_ADAM7_PASSES in png.h
+
+libpng can fill out those images or it can give them to you "as is".
+It is almost always better to have libpng handle the interlacing for you.
+If you want the images filled out, there are two ways to do that. The one
+mentioned in the PNG specification is to expand each pixel to cover
+those pixels that have not been read yet (the "rectangle" method).
+This results in a blocky image for the first pass, which gradually
+smooths out as more pixels are read. The other method is the "sparkle"
+method, where pixels are drawn only in their final locations, with the
+rest of the image remaining whatever colors they were initialized to
+before the start of the read. The first method usually looks better,
+but tends to be slower, as there are more pixels to put in the rows.
+
+If, as is likely, you want libpng to expand the images, call this before
+calling png_start_read_image() or png_read_update_info():
+
+ if (interlace_type == PNG_INTERLACE_ADAM7)
+ number_of_passes
+ = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed. Currently, this is seven,
+but may change if another interlace type is added. This function can be
+called even if the file is not interlaced, where it will return one pass.
+You then need to read the whole image 'number_of_passes' times. Each time
+will distribute the pixels from the current pass to the correct place in
+the output image, so you need to supply the same rows to png_read_rows in
+each pass.
+
+If you are not going to display the image after each pass, but are
+going to wait until the entire image is read in, use the sparkle
+effect. This effect is faster and the end result of either method
+is exactly the same. If you are planning on displaying the image
+after each pass, the "rectangle" effect is generally considered the
+better looking one.
+
+If you only want the "sparkle" effect, just call png_read_rows() as
+normal, with the third parameter NULL. Make sure you make pass over
+the image number_of_passes times, and you don't change the data in the
+rows between calls. You can change the locations of the data, just
+not the data. Each pass only writes the pixels appropriate for that
+pass, and assumes the data from previous passes is still valid.
+
+ png_read_rows(png_ptr, row_pointers, NULL,
+ number_of_rows);
+
+If you only want the first effect (the rectangles), do the same as
+before except pass the row buffer in the third parameter, and leave
+the second parameter NULL.
+
+ png_read_rows(png_ptr, NULL, row_pointers,
+ number_of_rows);
+
+If you don't want libpng to handle the interlacing details, just call
+png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
+Each of the images is a valid image by itself, however you will almost
+certainly need to distribute the pixels from each sub-image to the
+correct place. This is where everything gets very tricky.
+
+If you want to retrieve the separate images you must pass the correct
+number of rows to each successive call of png_read_rows(). The calculation
+gets pretty complicated for small images, where some sub-images may
+not even exist because either their width or height ends up zero.
+libpng provides two macros to help you in 1.5 and later versions:
+
+ png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
+ png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
+
+Respectively these tell you the width and height of the sub-image
+corresponding to the numbered pass. 'pass' is in in the range 0 to 6 -
+this can be confusing because the specification refers to the same passes
+as 1 to 7! Be careful, you must check both the width and height before
+calling png_read_rows() and not call it for that pass if either is zero.
+
+You can, of course, read each sub-image row by row. If you want to
+produce optimal code to make a pixel-by-pixel transformation of an
+interlaced image this is the best approach; read each row of each pass,
+transform it, and write it out to a new interlaced image.
+
+If you want to de-interlace the image yourself libpng provides further
+macros to help that tell you where to place the pixels in the output image.
+Because the interlacing scheme is rectangular - sub-image pixels are always
+arranged on a rectangular grid - all you need to know for each pass is the
+starting column and row in the output image of the first pixel plus the
+spacing between each pixel. As of libpng 1.5 there are four macros to
+retrieve this information:
+
+ png_uint_32 x = PNG_PASS_START_COL(pass);
+ png_uint_32 y = PNG_PASS_START_ROW(pass);
+ png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
+ png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
+
+These allow you to write the obvious loop:
+
+ png_uint_32 input_y = 0;
+ png_uint_32 output_y = PNG_PASS_START_ROW(pass);
+
+ while (output_y < output_image_height)
+ {
+ png_uint_32 input_x = 0;
+ png_uint_32 output_x = PNG_PASS_START_COL(pass);
+
+ while (output_x < output_image_width)
+ {
+ image[output_y][output_x] =
+ subimage[pass][input_y][input_x++];
+
+ output_x += xStep;
+ }
+
+ ++input_y;
+ output_y += yStep;
+ }
+
+Notice that the steps between successive output rows and columns are
+returned as shifts. This is possible because the pixels in the subimages
+are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
+image. In practice you may need to directly calculate the output coordinate
+given an input coordinate. libpng provides two further macros for this
+purpose:
+
+ png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
+ png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
+
+Finally a pair of macros are provided to tell you if a particular image
+row or column appears in a given pass:
+
+ int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
+ int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
+
+Bear in mind that you will probably also need to check the width and height
+of the pass in addition to the above to be sure the pass even exists!
+
+With any luck you are convinced by now that you don't want to do your own
+interlace handling. In reality normally the only good reason for doing this
+is if you are processing PNG files on a pixel-by-pixel basis and don't want
+to load the whole file into memory when it is interlaced.
+
+libpng includes a test program, pngvalid, that illustrates reading and
+writing of interlaced images. If you can't get interlacing to work in your
+code and don't want to leave it to libpng (the recommended approach) see
+how pngvalid.c does it.
+
+Finishing a sequential read
+
+After you are finished reading the image through the
+low-level interface, you can finish reading the file. If you are
+interested in comments or time, which may be stored either before or
+after the image data, you should pass the separate png_info struct if
+you want to keep the comments from before and after the image
+separate. If you are not interested, you can pass NULL.
+
+ png_read_end(png_ptr, end_info);
+
+When you are done, you can free all memory allocated by libpng like this:
+
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ &end_info);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+ png_free_data(png_ptr, info_ptr, mask, seq)
+
+ mask - identifies data to be freed, a mask
+ containing the bitwise OR of one or
+ more of
+ PNG_FREE_PLTE, PNG_FREE_TRNS,
+ PNG_FREE_HIST, PNG_FREE_ICCP,
+ PNG_FREE_PCAL, PNG_FREE_ROWS,
+ PNG_FREE_SCAL, PNG_FREE_SPLT,
+ PNG_FREE_TEXT, PNG_FREE_UNKN,
+ or simply PNG_FREE_ALL
+
+ seq - sequence number of item to be freed
+ (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng, and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+The default behavior is only to free data that was allocated internally
+by libpng. This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_zalloc() and passed in via a png_set_*() function, with
+
+ png_data_freer(png_ptr, info_ptr, freer, mask)
+
+ freer - one of
+ PNG_DESTROY_WILL_FREE_DATA
+ PNG_SET_WILL_FREE_DATA
+ PNG_USER_WILL_FREE_DATA
+
+ mask - which data elements are affected
+ same choices as in png_free_data()
+
+This function only affects data that has already been allocated.
+You can call this function after reading the PNG data but before calling
+any png_set_*() functions, to control whether the user or the png_set_*()
+function is responsible for freeing any existing data that might be present,
+and again after the png_set_*() functions to control whether the user
+or png_destroy_*() is supposed to free the data. When the user assumes
+responsibility for libpng-allocated data, the application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_zalloc() to allocate it.
+
+If you allocated your row_pointers in a single block, as suggested above in
+the description of the high level read interface, you must not transfer
+responsibility for freeing it to the png_set_rows or png_read_destroy function,
+because they would also try to free the individual row_pointers[i].
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key. Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+
+The png_free_data() function will turn off the "valid" flag for anything
+it frees. If you need to turn the flag off for a chunk that was freed by
+your application instead of by libpng, you can use
+
+ png_set_invalid(png_ptr, info_ptr, mask);
+
+ mask - identifies the chunks to be made invalid,
+ containing the bitwise OR of one or
+ more of
+ PNG_INFO_gAMA, PNG_INFO_sBIT,
+ PNG_INFO_cHRM, PNG_INFO_PLTE,
+ PNG_INFO_tRNS, PNG_INFO_bKGD,
+ PNG_INFO_hIST, PNG_INFO_pHYs,
+ PNG_INFO_oFFs, PNG_INFO_tIME,
+ PNG_INFO_pCAL, PNG_INFO_sRGB,
+ PNG_INFO_iCCP, PNG_INFO_sPLT,
+ PNG_INFO_sCAL, PNG_INFO_IDAT
+
+For a more compact example of reading a PNG image, see the file example.c.
+
+Reading PNG files progressively
+
+The progressive reader is slightly different then the non-progressive
+reader. Instead of calling png_read_info(), png_read_rows(), and
+png_read_end(), you make one call to png_process_data(), which calls
+callbacks when it has the info, a row, or the end of the image. You
+set up these callbacks with png_set_progressive_read_fn(). You don't
+have to worry about the input/output functions of libpng, as you are
+giving the library the data directly in png_process_data(). I will
+assume that you have read the section on reading PNG files above,
+so I will only highlight the differences (although I will show
+all of the code).
+
+png_structp png_ptr;
+png_infop info_ptr;
+
+ /* An example code fragment of how you would
+ initialize the progressive reader in your
+ application. */
+ int
+ initialize_png_reader()
+ {
+ png_ptr = png_create_read_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ info_ptr = png_create_info_struct(png_ptr);
+
+ if (!info_ptr)
+ {
+ png_destroy_read_struct(&png_ptr,
+ (png_infopp)NULL, (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ /* This one's new. You can provide functions
+ to be called when the header info is valid,
+ when each row is completed, and when the image
+ is finished. If you aren't using all functions,
+ you can specify NULL parameters. Even when all
+ three functions are NULL, you need to call
+ png_set_progressive_read_fn(). You can use
+ any struct as the user_ptr (cast to a void pointer
+ for the function call), and retrieve the pointer
+ from inside the callbacks using the function
+
+ png_get_progressive_ptr(png_ptr);
+
+ which will return a void pointer, which you have
+ to cast appropriately.
+ */
+ png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
+ info_callback, row_callback, end_callback);
+
+ return 0;
+ }
+
+ /* A code fragment that you call as you receive blocks
+ of data */
+ int
+ process_data(png_bytep buffer, png_uint_32 length)
+ {
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ /* This one's new also. Simply give it a chunk
+ of data from the file stream (in order, of
+ course). On machines with segmented memory
+ models machines, don't give it any more than
+ 64K. The library seems to run fine with sizes
+ of 4K. Although you can give it much less if
+ necessary (I assume you can give it chunks of
+ 1 byte, I haven't tried less then 256 bytes
+ yet). When this function returns, you may
+ want to display any rows that were generated
+ in the row callback if you don't already do
+ so there.
+ */
+ png_process_data(png_ptr, info_ptr, buffer, length);
+
+ /* At this point you can call png_process_data_skip if
+ you want to handle data the library will skip yourself;
+ it simply returns the number of bytes to skip (and stops
+ libpng skipping that number of bytes on the next
+ png_process_data call).
+ return 0;
+ }
+
+ /* This function is called (as set by
+ png_set_progressive_read_fn() above) when enough data
+ has been supplied so all of the header has been
+ read.
+ */
+ void
+ info_callback(png_structp png_ptr, png_infop info)
+ {
+ /* Do any setup here, including setting any of
+ the transformations mentioned in the Reading
+ PNG files section. For now, you _must_ call
+ either png_start_read_image() or
+ png_read_update_info() after all the
+ transformations are set (even if you don't set
+ any). You may start getting rows before
+ png_process_data() returns, so this is your
+ last chance to prepare for that.
+
+ This is where you turn on interlace handling,
+ assuming you don't want to do it yourself.
+
+ If you need to you can stop the processing of
+ your original input data at this point by calling
+ png_process_data_pause. This returns the number
+ of unprocessed bytes from the last png_process_data
+ call - it is up to you to ensure that the next call
+ sees these bytes again. If you don't want to bother
+ with this you can get libpng to cache the unread
+ bytes by setting the 'save' parameter (see png.h) but
+ then libpng will have to copy the data internally.
+ */
+ }
+
+ /* This function is called when each row of image
+ data is complete */
+ void
+ row_callback(png_structp png_ptr, png_bytep new_row,
+ png_uint_32 row_num, int pass)
+ {
+ /* If the image is interlaced, and you turned
+ on the interlace handler, this function will
+ be called for every row in every pass. Some
+ of these rows will not be changed from the
+ previous pass. When the row is not changed,
+ the new_row variable will be NULL. The rows
+ and passes are called in order, so you don't
+ really need the row_num and pass, but I'm
+ supplying them because it may make your life
+ easier.
+
+ If you did not turn on interlace handling then
+ the callback is called for each row of each
+ sub-image when the image is interlaced. In this
+ case 'row_num' is the row in the sub-image, not
+ the row in the output image as it is in all other
+ cases.
+
+ For the non-NULL rows of interlaced images when
+ you have switched on libpng interlace handling,
+ you must call png_progressive_combine_row()
+ passing in the row and the old row. You can
+ call this function for NULL rows (it will just
+ return) and for non-interlaced images (it just
+ does the memcpy for you) if it will make the
+ code easier. Thus, you can just do this for
+ all cases if you switch on interlace handling;
+ */
+
+ png_progressive_combine_row(png_ptr, old_row,
+ new_row);
+
+ /* where old_row is what was displayed for
+ previously for the row. Note that the first
+ pass (pass == 0, really) will completely cover
+ the old row, so the rows do not have to be
+ initialized. After the first pass (and only
+ for interlaced images), you will have to pass
+ the current row, and the function will combine
+ the old row and the new row.
+
+ You can also call png_process_data_pause in this
+ callback - see above.
+ */
+ }
+
+ void
+ end_callback(png_structp png_ptr, png_infop info)
+ {
+ /* This function is called after the whole image
+ has been read, including any chunks after the
+ image (up to and including the IEND). You
+ will usually have the same info chunk as you
+ had in the header, although some data may have
+ been added to the comments and time fields.
+
+ Most people won't do much here, perhaps setting
+ a flag that marks the image as finished.
+ */
+ }
+
+
+
+IV. Writing
+
+Much of this is very similar to reading. However, everything of
+importance is repeated here, so you won't have to constantly look
+back up in the reading section to understand writing.
+
+Setup
+
+You will want to do the I/O initialization before you get into libpng,
+so if it doesn't work, you don't have anything to undo. If you are not
+using the standard I/O functions, you will need to replace them with
+custom writing functions. See the discussion under Customizing libpng.
+
+ FILE *fp = fopen(file_name, "wb");
+
+ if (!fp)
+ return (ERROR);
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these can be both relatively large, you may not want to store these
+on the stack, unless you have stack space to spare. Of course, you
+will want to check if they return NULL. If you are also reading,
+you won't want to name your read structure and your write structure
+both "png_ptr"; you can call them anything you like, such as
+"read_ptr" and "write_ptr". Look at pngtest.c, for example.
+
+ png_structp png_ptr = png_create_write_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+ if (!info_ptr)
+ {
+ png_destroy_write_struct(&png_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+If you want to use your own memory allocation routines,
+define PNG_USER_MEM_SUPPORTED and use
+png_create_write_struct_2() instead of png_create_write_struct():
+
+ png_structp png_ptr = png_create_write_struct_2
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn, (png_voidp)
+ user_mem_ptr, user_malloc_fn, user_free_fn);
+
+After you have these structures, you will need to set up the
+error handling. When libpng encounters an error, it expects to
+longjmp() back to your routine. Therefore, you will need to call
+setjmp() and pass the png_jmpbuf(png_ptr). If you
+write the file from different routines, you will need to update
+the png_jmpbuf(png_ptr) every time you enter a new routine that will
+call a png_*() function. See your documentation of setjmp/longjmp
+for your compiler for more information on setjmp/longjmp. See
+the discussion on libpng error handling in the Customizing Libpng
+section below for more information on the libpng error handling.
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ fclose(fp);
+ return (ERROR);
+ }
+ ...
+ return;
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the output code. The default for libpng is to
+use the C function fwrite(). If you use this, you will need to pass a
+valid FILE * in the function png_init_io(). Be sure that the file is
+opened in binary mode. Again, if you wish to handle writing data in
+another way, see the discussion on libpng I/O handling in the Customizing
+Libpng section below.
+
+ png_init_io(png_ptr, fp);
+
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+ png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
+Write callbacks
+
+At this point, you can set up a callback function that will be
+called after each row has been written, which you can use to control
+a progress meter or the like. It's demonstrated in pngtest.c.
+You must supply a function
+
+ void write_row_callback(png_structp png_ptr, png_uint_32 row,
+ int pass);
+ {
+ /* put your code here */
+ }
+
+(You can give it another name that you like instead of "write_row_callback")
+
+To inform libpng about your function, use
+
+ png_set_write_status_fn(png_ptr, write_row_callback);
+
+You now have the option of modifying how the compression library will
+run. The following functions are mainly for testing, but may be useful
+in some cases, like if you need to write PNG files extremely fast and
+are willing to give up some compression, or if you want to get the
+maximum possible compression at the expense of slower writing. If you
+have no special needs in this area, let the library do what it wants by
+not calling this function at all, as it has been tuned to deliver a good
+speed/compression ratio. The second parameter to png_set_filter() is
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream). The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline. See the PNG specification for details on the specific
+filter types.
+
+
+ /* turn on or off filtering, and/or choose
+ specific filters. You can use either a single
+ PNG_FILTER_VALUE_NAME or the bitwise OR of one
+ or more PNG_FILTER_NAME masks.
+ */
+ png_set_filter(png_ptr, 0,
+ PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE |
+ PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB |
+ PNG_FILTER_UP | PNG_FILTER_VALUE_UP |
+ PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG |
+ PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
+ PNG_ALL_FILTERS);
+
+If an application wants to start and stop using particular filters during
+compression, it should start out with all of the filters (to ensure that
+the previous row of pixels will be stored in case it's needed later),
+and then add and remove them after the start of compression.
+
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
+The png_set_compression_*() functions interface to the zlib compression
+library, and should mostly be ignored unless you really know what you are
+doing. The only generally useful call is png_set_compression_level()
+which changes how much time zlib spends on trying to compress the image
+data. See the Compression Library (zlib.h and algorithm.txt, distributed
+with zlib) for details on the compression levels.
+
+ /* set the zlib compression level */
+ png_set_compression_level(png_ptr,
+ Z_BEST_COMPRESSION);
+
+ /* set other zlib parameters */
+ png_set_compression_mem_level(png_ptr, 8);
+ png_set_compression_strategy(png_ptr,
+ Z_DEFAULT_STRATEGY);
+ png_set_compression_window_bits(png_ptr, 15);
+ png_set_compression_method(png_ptr, 8);
+ png_set_compression_buffer_size(png_ptr, 8192)
+
+extern PNG_EXPORT(void,png_set_zbuf_size)
+
+Setting the contents of info for output
+
+You now need to fill in the png_info structure with all the data you
+wish to write before the actual image. Note that the only thing you
+are allowed to write after the image is the text chunks and the time
+chunk (as of PNG Specification 1.2, anyway). See png_write_end() and
+the latest PNG specification for more information on that. If you
+wish to write them before the image, fill them in now, and flag that
+data as being valid. If you want to wait until after the data, don't
+fill them until png_write_end(). For all the fields in png_info and
+their data types, see png.h. For explanations of what the fields
+contain, see the PNG specification.
+
+Some of the more important parts of the png_info are:
+
+ png_set_IHDR(png_ptr, info_ptr, width, height,
+ bit_depth, color_type, interlace_type,
+ compression_type, filter_method)
+
+ width - holds the width of the image
+ in pixels (up to 2^31).
+
+ height - holds the height of the image
+ in pixels (up to 2^31).
+
+ bit_depth - holds the bit depth of one of the
+ image channels.
+ (valid values are 1, 2, 4, 8, 16
+ and depend also on the
+ color_type. See also significant
+ bits (sBIT) below).
+
+ color_type - describes which color/alpha
+ channels are present.
+ PNG_COLOR_TYPE_GRAY
+ (bit depths 1, 2, 4, 8, 16)
+ PNG_COLOR_TYPE_GRAY_ALPHA
+ (bit depths 8, 16)
+ PNG_COLOR_TYPE_PALETTE
+ (bit depths 1, 2, 4, 8)
+ PNG_COLOR_TYPE_RGB
+ (bit_depths 8, 16)
+ PNG_COLOR_TYPE_RGB_ALPHA
+ (bit_depths 8, 16)
+
+ PNG_COLOR_MASK_PALETTE
+ PNG_COLOR_MASK_COLOR
+ PNG_COLOR_MASK_ALPHA
+
+ interlace_type - PNG_INTERLACE_NONE or
+ PNG_INTERLACE_ADAM7
+
+ compression_type - (must be
+ PNG_COMPRESSION_TYPE_DEFAULT)
+
+ filter_method - (must be PNG_FILTER_TYPE_DEFAULT
+ or, if you are writing a PNG to
+ be embedded in a MNG datastream,
+ can also be
+ PNG_INTRAPIXEL_DIFFERENCING)
+
+If you call png_set_IHDR(), the call must appear before any of the
+other png_set_*() functions, because they might require access to some of
+the IHDR settings. The remaining png_set_*() functions can be called
+in any order.
+
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
+
+ png_set_PLTE(png_ptr, info_ptr, palette,
+ num_palette);
+
+ palette - the palette for the file
+ (array of png_color)
+ num_palette - number of entries in the palette
+
+ png_set_gAMA(png_ptr, info_ptr, file_gamma);
+ png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+
+ file_gamma - the gamma at which the image was
+ created (PNG_INFO_gAMA)
+
+ int_file_gamma - 100,000 times the gamma at which
+ the image was created
+
+ png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+ srgb_intent - the rendering intent
+ (PNG_INFO_sRGB) The presence of
+ the sRGB chunk means that the pixel
+ data is in the sRGB color space.
+ This chunk also implies specific
+ values of gAMA and cHRM. Rendering
+ intent is the CSS-1 property that
+ has been defined by the International
+ Color Consortium
+ (http://www.color.org).
+ It can be one of
+ PNG_sRGB_INTENT_SATURATION,
+ PNG_sRGB_INTENT_PERCEPTUAL,
+ PNG_sRGB_INTENT_ABSOLUTE, or
+ PNG_sRGB_INTENT_RELATIVE.
+
+
+ png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
+ srgb_intent);
+
+ srgb_intent - the rendering intent
+ (PNG_INFO_sRGB) The presence of the
+ sRGB chunk means that the pixel
+ data is in the sRGB color space.
+ This function also causes gAMA and
+ cHRM chunks with the specific values
+ that are consistent with sRGB to be
+ written.
+
+ png_set_iCCP(png_ptr, info_ptr, name, compression_type,
+ profile, proflen);
+
+ name - The profile name.
+
+ compression_type - The compression type; always
+ PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+ You may give NULL to this argument to
+ ignore it.
+
+ profile - International Color Consortium color
+ profile data. May contain NULs.
+
+ proflen - length of profile data in bytes.
+
+ png_set_sBIT(png_ptr, info_ptr, sig_bit);
+
+ sig_bit - the number of significant bits for
+ (PNG_INFO_sBIT) each of the gray, red,
+ green, and blue channels, whichever are
+ appropriate for the given color type
+ (png_color_16)
+
+ png_set_tRNS(png_ptr, info_ptr, trans_alpha,
+ num_trans, trans_color);
+
+ trans_alpha - array of alpha (transparency)
+ entries for palette (PNG_INFO_tRNS)
+
+ trans_color - graylevel or color sample values
+ (in order red, green, blue) of the
+ single transparent color for
+ non-paletted images (PNG_INFO_tRNS)
+
+ num_trans - number of transparent entries
+ (PNG_INFO_tRNS)
+
+ png_set_hIST(png_ptr, info_ptr, hist);
+
+ hist - histogram of palette (array of
+ png_uint_16) (PNG_INFO_hIST)
+
+ png_set_tIME(png_ptr, info_ptr, mod_time);
+
+ mod_time - time image was last modified
+ (PNG_VALID_tIME)
+
+ png_set_bKGD(png_ptr, info_ptr, background);
+
+ background - background color (PNG_VALID_bKGD)
+
+ png_set_text(png_ptr, info_ptr, text_ptr, num_text);
+
+ text_ptr - array of png_text holding image
+ comments
+
+ text_ptr[i].compression - type of compression used
+ on "text" PNG_TEXT_COMPRESSION_NONE
+ PNG_TEXT_COMPRESSION_zTXt
+ PNG_ITXT_COMPRESSION_NONE
+ PNG_ITXT_COMPRESSION_zTXt
+ text_ptr[i].key - keyword for comment. Must contain
+ 1-79 characters.
+ text_ptr[i].text - text comments for current
+ keyword. Can be NULL or empty.
+ text_ptr[i].text_length - length of text string,
+ after decompression, 0 for iTXt
+ text_ptr[i].itxt_length - length of itxt string,
+ after decompression, 0 for tEXt/zTXt
+ text_ptr[i].lang - language of comment (NULL or
+ empty for unknown).
+ text_ptr[i].translated_keyword - keyword in UTF-8 (NULL
+ or empty for unknown).
+ Note that the itxt_length, lang, and lang_key
+ members of the text_ptr structure only exist
+ when the library is built with iTXt chunk support.
+
+ num_text - number of comments
+
+ png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
+ num_spalettes);
+
+ palette_ptr - array of png_sPLT_struct structures
+ to be added to the list of palettes
+ in the info structure.
+ num_spalettes - number of palette structures to be
+ added.
+
+ png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
+ unit_type);
+
+ offset_x - positive offset from the left
+ edge of the screen
+
+ offset_y - positive offset from the top
+ edge of the screen
+
+ unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+ png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
+ unit_type);
+
+ res_x - pixels/unit physical resolution
+ in x direction
+
+ res_y - pixels/unit physical resolution
+ in y direction
+
+ unit_type - PNG_RESOLUTION_UNKNOWN,
+ PNG_RESOLUTION_METER
+
+ png_set_sCAL(png_ptr, info_ptr, unit, width, height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are doubles)
+
+ png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are strings like "2.54")
+
+ png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
+ num_unknowns)
+
+ unknowns - array of png_unknown_chunk
+ structures holding unknown chunks
+ unknowns[i].name - name of unknown chunk
+ unknowns[i].data - data of unknown chunk
+ unknowns[i].size - size of unknown chunk's data
+ unknowns[i].location - position to write chunk in file
+ 0: do not write chunk
+ PNG_HAVE_IHDR: before PLTE
+ PNG_HAVE_PLTE: before IDAT
+ PNG_AFTER_IDAT: after IDAT
+
+The "location" member is set automatically according to
+what part of the output file has already been written.
+You can change its value after calling png_set_unknown_chunks()
+as demonstrated in pngtest.c. Within each of the "locations",
+the chunks are sequenced according to their position in the
+structure (that is, the value of "i", which is the order in which
+the chunk was either read from the input file or defined with
+png_set_unknown_chunks).
+
+A quick word about text and num_text. text is an array of png_text
+structures. num_text is the number of valid structures in the array.
+Each png_text structure holds a language code, a keyword, a text value,
+and a compression type.
+
+The compression types have the same valid numbers as the compression
+types of the image data. Currently, the only valid number is zero.
+However, you can store text either compressed or uncompressed, unlike
+images, which always have to be compressed. So if you don't want the
+text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
+Because tEXt and zTXt chunks don't have a language field, if you
+specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
+any language code or translated keyword will not be written out.
+
+Until text gets around 1000 bytes, it is not worth compressing it.
+After the text has been written out to the file, the compression type
+is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
+so that it isn't written out again at the end (in case you are calling
+png_write_end() with the same struct).
+
+The keywords that are given in the PNG Specification are:
+
+ Title Short (one line) title or
+ caption for image
+
+ Author Name of image's creator
+
+ Description Description of image (possibly long)
+
+ Copyright Copyright notice
+
+ Creation Time Time of original image creation
+ (usually RFC 1123 format, see below)
+
+ Software Software used to create the image
+
+ Disclaimer Legal disclaimer
+
+ Warning Warning of nature of content
+
+ Source Device used to create the image
+
+ Comment Miscellaneous comment; conversion
+ from other image format
+
+The keyword-text pairs work like this. Keywords should be short
+simple descriptions of what the comment is about. Some typical
+keywords are found in the PNG specification, as is some recommendations
+on keywords. You can repeat keywords in a file. You can even write
+some text before the image and some after. For example, you may want
+to put a description of the image before the image, but leave the
+disclaimer until after, so viewers working over modem connections
+don't have to wait for the disclaimer to go over the modem before
+they start seeing the image. Finally, keywords should be full
+words, not abbreviations. Keywords and text are in the ISO 8859-1
+(Latin-1) character set (a superset of regular ASCII) and can not
+contain NUL characters, and should not contain control or other
+unprintable characters. To make the comments widely readable, stick
+with basic ASCII, and avoid machine specific character set extensions
+like the IBM-PC character set. The keyword must be present, but
+you can leave off the text string on non-compressed pairs.
+Compressed pairs must have a text string, as only the text string
+is compressed anyway, so the compression would be meaningless.
+
+PNG supports modification time via the png_time structure. Two
+conversion routines are provided, png_convert_from_time_t() for
+time_t and png_convert_from_struct_tm() for struct tm. The
+time_t routine uses gmtime(). You don't have to use either of
+these, but if you wish to fill in the png_time structure directly,
+you should provide the time in universal time (GMT) if possible
+instead of your local time. Note that the year number is the full
+year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
+that months start with 1.
+
+If you want to store the time of the original image creation, you should
+use a plain tEXt chunk with the "Creation Time" keyword. This is
+necessary because the "creation time" of a PNG image is somewhat vague,
+depending on whether you mean the PNG file, the time the image was
+created in a non-PNG format, a still photo from which the image was
+scanned, or possibly the subject matter itself. In order to facilitate
+machine-readable dates, it is recommended that the "Creation Time"
+tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
+although this isn't a requirement. Unlike the tIME chunk, the
+"Creation Time" tEXt chunk is not expected to be automatically changed
+by the software. To facilitate the use of RFC 1123 dates, a function
+png_convert_to_rfc1123(png_timep) is provided to convert from PNG
+time to an RFC 1123 format string.
+
+Writing unknown chunks
+
+You can use the png_set_unknown_chunks function to queue up chunks
+for writing. You give it a chunk name, raw data, and a size; that's
+all there is to it. The chunks will be written by the next following
+png_write_info_before_PLTE, png_write_info, or png_write_end function.
+Any chunks previously read into the info structure's unknown-chunk
+list will also be written out in a sequence that satisfies the PNG
+specification's ordering rules.
+
+The high-level write interface
+
+At this point there are two ways to proceed; through the high-level
+write interface, or through a sequence of low-level write operations.
+You can use the high-level interface if your image data is present
+in the info structure. All defined output
+transformations are permitted, enabled by the following masks.
+
+ PNG_TRANSFORM_IDENTITY No transformation
+ PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples
+ PNG_TRANSFORM_PACKSWAP Change order of packed
+ pixels to LSB first
+ PNG_TRANSFORM_INVERT_MONO Invert monochrome images
+ PNG_TRANSFORM_SHIFT Normalize pixels to the
+ sBIT depth
+ PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
+ to BGRA
+ PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
+ to AG
+ PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
+ to transparency
+ PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
+ PNG_TRANSFORM_STRIP_FILLER Strip out filler
+ bytes (deprecated).
+ PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
+ filler bytes
+ PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing
+ filler bytes
+
+If you have valid image data in the info structure (you can use
+png_set_rows() to put image data in the info structure), simply do this:
+
+ png_write_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some set of
+transformation flags. This call is equivalent to png_write_info(),
+followed the set of transformations indicated by the transform mask,
+then png_write_image(), and finally png_write_end().
+
+(The final parameter of this call is not yet used. Someday it might point
+to transformation parameters required by some future output transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+
+The low-level write interface
+
+If you are going the low-level route instead, you are now ready to
+write all the file information up to the actual image data. You do
+this with a call to png_write_info().
+
+ png_write_info(png_ptr, info_ptr);
+
+Note that there is one transformation you may need to do before
+png_write_info(). In PNG files, the alpha channel in an image is the
+level of opacity. If your data is supplied as a level of transparency,
+you can invert the alpha channel before you write it, so that 0 is
+fully transparent and 255 (in 8-bit or paletted images) or 65535
+(in 16-bit images) is fully opaque, with
+
+ png_set_invert_alpha(png_ptr);
+
+This must appear before png_write_info() instead of later with the
+other transformations because in the case of paletted images the tRNS
+chunk data has to be inverted before the tRNS chunk is written. If
+your image is not a paletted image, the tRNS data (which in such cases
+represents a single color to be rendered as transparent) won't need to
+be changed, and you can safely do this transformation after your
+png_write_info() call.
+
+If you need to write a private chunk that you want to appear before
+the PLTE chunk when PLTE is present, you can write the PNG info in
+two steps, and insert code to write your own chunk between them:
+
+ png_write_info_before_PLTE(png_ptr, info_ptr);
+ png_set_unknown_chunks(png_ptr, info_ptr, ...);
+ png_write_info(png_ptr, info_ptr);
+
+After you've written the file information, you can set up the library
+to handle any special transformations of the image data. The various
+ways to transform the data will be described in the order that they
+should occur. This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths. Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data. For example, don't swap red and blue on grayscale data.
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code tells
+the library to strip input data that has 4 or 8 bytes per pixel down
+to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
+bytes per pixel).
+
+ png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
+PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
+is stored XRGB or RGBX.
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit files.
+If the data is supplied at 1 pixel per byte, use this code, which will
+correctly pack the pixels into a single byte:
+
+ png_set_packing(png_ptr);
+
+PNG files reduce possible bit depths to 1, 2, 4, 8, and 16. If your
+data is of another bit depth, you can write an sBIT chunk into the
+file so that decoders can recover the original data if desired.
+
+ /* Set the true bit depth of the image data */
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ sig_bit.red = true_bit_depth;
+ sig_bit.green = true_bit_depth;
+ sig_bit.blue = true_bit_depth;
+ }
+
+ else
+ {
+ sig_bit.gray = true_bit_depth;
+ }
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ sig_bit.alpha = true_bit_depth;
+ }
+
+ png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+If the data is stored in the row buffer in a bit depth other than
+one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
+this will scale the values to appear to be the correct bit depth as
+is required by PNG.
+
+ png_set_shift(png_ptr, &sig_bit);
+
+PNG files store 16 bit pixels in network byte order (big-endian,
+ie. most significant bits first). This code would be used if they are
+supplied the other way (little-endian, i.e. least significant bits
+first, the way PCs store them):
+
+ if (bit_depth > 8)
+ png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+ if (bit_depth < 8)
+ png_set_packswap(png_ptr);
+
+PNG files store 3 color pixels in red, green, blue order. This code
+would be used if they are supplied as blue, green, red:
+
+ png_set_bgr(png_ptr);
+
+PNG files describe monochrome as black being zero and white being
+one. This code would be used if the pixels are supplied with this reversed
+(black being one and white being zero):
+
+ png_set_invert_mono(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs. This is done by setting a callback
+with
+
+ png_set_write_user_transform_fn(png_ptr,
+ write_transform_fn);
+
+You must supply the function
+
+ void write_transform_fn(png_structp png_ptr ptr,
+ row_info_ptr row_info, png_bytep data)
+
+See pngtest.c for a working example. Your function will be called
+before any of the other transformations are processed. If supported
+libpng also supplies an information routine that may be called from
+your callback:
+
+ png_get_current_row_number(png_ptr);
+
+This returns the current row passed to the transform. Even with interlaced
+images the value returned is the row in the final output image.
+
+You can also set up a pointer to a user structure for use by your
+callback function.
+
+ png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
+
+The user_channels and user_depth parameters of this function are ignored
+when writing; you can set them to zero as shown.
+
+You can retrieve the pointer via the function png_get_user_transform_ptr().
+For example:
+
+ voidp write_user_transform_ptr =
+ png_get_user_transform_ptr(png_ptr);
+
+It is possible to have libpng flush any pending output, either manually,
+or automatically after a certain number of lines have been written. To
+flush the output stream a single time call:
+
+ png_write_flush(png_ptr);
+
+and to have libpng flush the output stream periodically after a certain
+number of scanlines have been written, call:
+
+ png_set_flush(png_ptr, nrows);
+
+Note that the distance between rows is from the last time png_write_flush()
+was called, or the first row of the image if it has never been called.
+So if you write 50 lines, and then png_set_flush 25, it will flush the
+output on the next scanline, and every 25 lines thereafter, unless
+png_write_flush() is called before 25 more lines have been written.
+If nrows is too small (less than about 10 lines for a 640 pixel wide
+RGB image) the image compression may decrease noticeably (although this
+may be acceptable for real-time applications). Infrequent flushing will
+only degrade the compression performance by a few percent over images
+that do not use flushing.
+
+Writing the image data
+
+That's it for the transformations. Now you can write the image data.
+The simplest way to do this is in one function call. If you have the
+whole image in memory, you can just call png_write_image() and libpng
+will write the image. You will need to pass in an array of pointers to
+each row. This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() or call this function multiple
+times, or any of that other stuff necessary with png_write_rows().
+
+ png_write_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+ png_byte *row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to write the whole image at once, you can
+use png_write_rows() instead. If the file is not interlaced,
+this is simple:
+
+ png_write_rows(png_ptr, row_pointers,
+ number_of_rows);
+
+row_pointers is the same as in the png_write_image() call.
+
+If you are just writing one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+ png_bytep row_pointer = row;
+
+ png_write_row(png_ptr, row_pointer);
+
+When the file is interlaced, things can get a good deal more complicated.
+The only currently (as of the PNG Specification version 1.2, dated July
+1999) defined interlacing scheme for PNG files is the "Adam7" interlace
+scheme, that breaks down an image into seven smaller images of varying
+size. libpng will build these images for you, or you can do them
+yourself. If you want to build them yourself, see the PNG specification
+for details of which pixels to write when.
+
+If you don't want libpng to handle the interlacing details, just
+use png_set_interlace_handling() and call png_write_rows() the
+correct number of times to write all the sub-images
+(png_set_interlace_handling() returns the number of sub-images.)
+
+If you want libpng to build the sub-images, call this before you start
+writing any rows:
+
+ number_of_passes = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed. Currently, this is seven,
+but may change if another interlace type is added.
+
+Then write the complete image number_of_passes times.
+
+ png_write_rows(png_ptr, row_pointers, number_of_rows);
+
+Think carefully before you write an interlaced image. Typically code that
+reads such images reads all the image data into memory, uncompressed, before
+doing any processing. Only code that can display an image on the fly can
+take advantage of the interlacing and even then the image has to be exactly
+the correct size for the output device, because scaling an image requires
+adjacent pixels and these are not available until all the passes have been
+read.
+
+If you do write an interlaced image you will hardly ever need to handle
+the interlacing yourself. Call png_set_interlace_handling() and use the
+approach described above.
+
+The only time it is conceivable that you will really need to write an
+interlaced image pass-by-pass is when you have read one pass by pass and
+made some pixel-by-pixel transformation to it, as described in the read
+code above. In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
+to determine the size of each sub-image in turn and simply write the rows
+you obtained from the read code.
+
+Finishing a sequential write
+
+After you are finished writing the image, you should finish writing
+the file. If you are interested in writing comments or time, you should
+pass an appropriately filled png_info pointer. If you are not interested,
+you can pass NULL.
+
+ png_write_end(png_ptr, info_ptr);
+
+When you are done, you can free all memory used by libpng like this:
+
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+ png_free_data(png_ptr, info_ptr, mask, seq)
+
+ mask - identifies data to be freed, a mask
+ containing the bitwise OR of one or
+ more of
+ PNG_FREE_PLTE, PNG_FREE_TRNS,
+ PNG_FREE_HIST, PNG_FREE_ICCP,
+ PNG_FREE_PCAL, PNG_FREE_ROWS,
+ PNG_FREE_SCAL, PNG_FREE_SPLT,
+ PNG_FREE_TEXT, PNG_FREE_UNKN,
+ or simply PNG_FREE_ALL
+
+ seq - sequence number of item to be freed
+ (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng, and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+If you allocated data such as a palette that you passed in to libpng
+with png_set_*, you must not free it until just before the call to
+png_destroy_write_struct().
+
+The default behavior is only to free data that was allocated internally
+by libpng. This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_zalloc() and passed in via a png_set_*() function, with
+
+ png_data_freer(png_ptr, info_ptr, freer, mask)
+
+ freer - one of
+ PNG_DESTROY_WILL_FREE_DATA
+ PNG_SET_WILL_FREE_DATA
+ PNG_USER_WILL_FREE_DATA
+
+ mask - which data elements are affected
+ same choices as in png_free_data()
+
+For example, to transfer responsibility for some data from a read structure
+to a write structure, you could use
+
+ png_data_freer(read_ptr, read_info_ptr,
+ PNG_USER_WILL_FREE_DATA,
+ PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+ png_data_freer(write_ptr, write_info_ptr,
+ PNG_DESTROY_WILL_FREE_DATA,
+ PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+thereby briefly reassigning responsibility for freeing to the user but
+immediately afterwards reassigning it once more to the write_destroy
+function. Having done this, it would then be safe to destroy the read
+structure and continue to use the PLTE, tRNS, and hIST data in the write
+structure.
+
+This function only affects data that has already been allocated.
+You can call this function before calling after the png_set_*() functions
+to control whether the user or png_destroy_*() is supposed to free the data.
+When the user assumes responsibility for libpng-allocated data, the
+application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_zalloc() to allocate it.
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key. Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+For a more compact example of writing a PNG image, see the file example.c.
+
+V. Modifying/Customizing libpng:
+
+There are two issues here. The first is changing how libpng does
+standard things like memory allocation, input/output, and error handling.
+The second deals with more complicated things like adding new chunks,
+adding new transformations, and generally changing how libpng works.
+Both of those are compile-time issues; that is, they are generally
+determined at the time the code is written, and there is rarely a need
+to provide the user with a means of changing them.
+
+Memory allocation, input/output, and error handling
+
+All of the memory allocation, input/output, and error handling in libpng
+goes through callbacks that are user-settable. The default routines are
+in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change
+these functions, call the appropriate png_set_*_fn() function.
+
+Memory allocation is done through the functions png_malloc(), png_calloc(),
+and png_free(). These currently just call the standard C functions.
+png_calloc() calls png_malloc() and then clears the newly
+allocated memory to zero. There is limited support for certain systems
+with segmented memory architectures and the types of pointers declared by
+png.h match this; you will have to use appropriate pointers in your
+application. Since it is
+unlikely that the method of handling memory allocation on a platform
+will change between applications, these functions must be modified in
+the library at compile time. If you prefer to use a different method
+of allocating and freeing data, you can use png_create_read_struct_2() or
+png_create_write_struct_2() to register your own functions as described
+above. These functions also provide a void pointer that can be retrieved
+via
+
+ mem_ptr=png_get_mem_ptr(png_ptr);
+
+Your replacement memory functions must have prototypes as follows:
+
+ png_voidp malloc_fn(png_structp png_ptr,
+ png_alloc_size_t size);
+
+ void free_fn(png_structp png_ptr, png_voidp ptr);
+
+Your malloc_fn() must return NULL in case of failure. The png_malloc()
+function will normally call png_error() if it receives a NULL from the
+system memory allocator or from your replacement malloc_fn().
+
+Your free_fn() will never be called with a NULL ptr, since libpng's
+png_free() checks for NULL before calling free_fn().
+
+Input/Output in libpng is done through png_read() and png_write(),
+which currently just call fread() and fwrite(). The FILE * is stored in
+png_struct and is initialized via png_init_io(). If you wish to change
+the method of I/O, the library supplies callbacks that you can set
+through the function png_set_read_fn() and png_set_write_fn() at run
+time, instead of calling the png_init_io() function. These functions
+also provide a void pointer that can be retrieved via the function
+png_get_io_ptr(). For example:
+
+ png_set_read_fn(png_structp read_ptr,
+ voidp read_io_ptr, png_rw_ptr read_data_fn)
+
+ png_set_write_fn(png_structp write_ptr,
+ voidp write_io_ptr, png_rw_ptr write_data_fn,
+ png_flush_ptr output_flush_fn);
+
+ voidp read_io_ptr = png_get_io_ptr(read_ptr);
+ voidp write_io_ptr = png_get_io_ptr(write_ptr);
+
+The replacement I/O functions must have prototypes as follows:
+
+ void user_read_data(png_structp png_ptr,
+ png_bytep data, png_size_t length);
+
+ void user_write_data(png_structp png_ptr,
+ png_bytep data, png_size_t length);
+
+ void user_flush_data(png_structp png_ptr);
+
+The user_read_data() function is responsible for detecting and
+handling end-of-data errors.
+
+Supplying NULL for the read, write, or flush functions sets them back
+to using the default C stream functions, which expect the io_ptr to
+point to a standard *FILE structure. It is probably a mistake
+to use NULL for one of write_data_fn and output_flush_fn but not both
+of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
+It is an error to read from a write stream, and vice versa.
+
+Error handling in libpng is done through png_error() and png_warning().
+Errors handled through png_error() are fatal, meaning that png_error()
+should never return to its caller. Currently, this is handled via
+setjmp() and longjmp() (unless you have compiled libpng with
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
+but you could change this to do things like exit() if you should wish,
+as long as your function does not return.
+
+On non-fatal errors, png_warning() is called
+to print a warning message, and then control returns to the calling code.
+By default png_error() and png_warning() print a message on stderr via
+fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
+(because you don't want the messages) or PNG_NO_STDIO defined (because
+fprintf() isn't available). If you wish to change the behavior of the error
+functions, you will need to set up your own message callbacks. These
+functions are normally supplied at the time that the png_struct is created.
+It is also possible to redirect errors and warnings to your own replacement
+functions after png_create_*_struct() has been called by calling:
+
+ png_set_error_fn(png_structp png_ptr,
+ png_voidp error_ptr, png_error_ptr error_fn,
+ png_error_ptr warning_fn);
+
+ png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
+If NULL is supplied for either error_fn or warning_fn, then the libpng
+default function will be used, calling fprintf() and/or longjmp() if a
+problem is encountered. The replacement error functions should have
+parameters as follows:
+
+ void user_error_fn(png_structp png_ptr,
+ png_const_charp error_msg);
+
+ void user_warning_fn(png_structp png_ptr,
+ png_const_charp warning_msg);
+
+The motivation behind using setjmp() and longjmp() is the C++ throw and
+catch exception handling methods. This makes the code much easier to write,
+as there is no need to check every return code of every function call.
+However, there are some uncertainties about the status of local variables
+after a longjmp, so the user may want to be careful about doing anything
+after setjmp returns non-zero besides returning itself. Consult your
+compiler documentation for more details. For an alternative approach, you
+may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net).
+
+Custom chunks
+
+If you need to read or write custom chunks, you may need to get deeper
+into the libpng code. The library now has mechanisms for storing
+and writing chunks of unknown type; you can even declare callbacks
+for custom chunks. However, this may not be good enough if the
+library code itself needs to know about interactions between your
+chunk and existing `intrinsic' chunks.
+
+If you need to write a new intrinsic chunk, first read the PNG
+specification. Acquire a first level of understanding of how it works.
+Pay particular attention to the sections that describe chunk names,
+and look at how other chunks were designed, so you can do things
+similarly. Second, check out the sections of libpng that read and
+write chunks. Try to find a chunk that is similar to yours and use
+it as a template. More details can be found in the comments inside
+the code. It is best to handle unknown chunks in a generic method,
+via callback functions, instead of by modifying libpng functions.
+
+If you wish to write your own transformation for the data, look through
+the part of the code that does the transformations, and check out some of
+the simpler ones to get an idea of how they work. Try to find a similar
+transformation to the one you want to add and copy off of it. More details
+can be found in the comments inside the code itself.
+
+Configuring for 16 bit platforms
+
+You will want to look into zconf.h to tell zlib (and thus libpng) that
+it cannot allocate more then 64K at a time. Even if you can, the memory
+won't be accessible. So limit zlib and libpng to 64K by defining MAXSEG_64K.
+
+Configuring for DOS
+
+For DOS users who only have access to the lower 640K, you will
+have to limit zlib's memory usage via a png_set_compression_mem_level()
+call. See zlib.h or zconf.h in the zlib library for more information.
+
+Configuring for Medium Model
+
+Libpng's support for medium model has been tested on most of the popular
+compilers. Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
+defined, and FAR gets defined to far in pngconf.h, and you should be
+all set. Everything in the library (except for zlib's structure) is
+expecting far data. You must use the typedefs with the p or pp on
+the end for pointers (or at least look at them and be careful). Make
+note that the rows of data are defined as png_bytepp, which is an
+unsigned char far * far *.
+
+Configuring for gui/windowing platforms:
+
+You will need to write new error and warning functions that use the GUI
+interface, as described previously, and set them to be the error and
+warning functions at the time that png_create_*_struct() is called,
+in order to have them available during the structure initialization.
+They can be changed later via png_set_error_fn(). On some compilers,
+you may also have to change the memory allocators (png_malloc, etc.).
+
+Configuring for compiler xxx:
+
+All includes for libpng are in pngconf.h. If you need to add, change
+or delete an include, this is the place to do it.
+The includes that are not needed outside libpng are placed in pngpriv.h,
+which is only used by the routines inside libpng itself.
+The files in libpng proper only include pngpriv.h and png.h, which
+in turn includes pngconf.h.
+
+Configuring zlib:
+
+There are special functions to configure the compression. Perhaps the
+most useful one changes the compression level, which currently uses
+input compression values in the range 0 - 9. The library normally
+uses the default compression level (Z_DEFAULT_COMPRESSION = 6). Tests
+have shown that for a large majority of images, compression values in
+the range 3-6 compress nearly as well as higher levels, and do so much
+faster. For online applications it may be desirable to have maximum speed
+(Z_BEST_SPEED = 1). With versions of zlib after v0.99, you can also
+specify no compression (Z_NO_COMPRESSION = 0), but this would create
+files larger than just storing the raw bitmap. You can specify the
+compression level by calling:
+
+ png_set_compression_level(png_ptr, level);
+
+Another useful one is to reduce the memory level used by the library.
+The memory level defaults to 8, but it can be lowered if you are
+short on memory (running DOS, for example, where you only have 640K).
+Note that the memory level does have an effect on compression; among
+other things, lower levels will result in sections of incompressible
+data being emitted in smaller stored blocks, with a correspondingly
+larger relative overhead of up to 15% in the worst case.
+
+ png_set_compression_mem_level(png_ptr, level);
+
+The other functions are for configuring zlib. They are not recommended
+for normal use and may result in writing an invalid PNG file. See
+zlib.h for more information on what these mean.
+
+ png_set_compression_strategy(png_ptr,
+ strategy);
+
+ png_set_compression_window_bits(png_ptr,
+ window_bits);
+
+ png_set_compression_method(png_ptr, method);
+ png_set_compression_buffer_size(png_ptr, size);
+
+Controlling row filtering
+
+If you want to control whether libpng uses filtering or not, which
+filters are used, and how it goes about picking row filters, you
+can call one of these functions. The selection and configuration
+of row filters can have a significant impact on the size and
+encoding speed and a somewhat lesser impact on the decoding speed
+of an image. Filtering is enabled by default for RGB and grayscale
+images (with and without alpha), but not for paletted images nor
+for any images with bit depths less than 8 bits/pixel.
+
+The 'method' parameter sets the main filtering method, which is
+currently only '0' in the PNG 1.2 specification. The 'filters'
+parameter sets which filter(s), if any, should be used for each
+scanline. Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS
+to turn filtering on and off, respectively.
+
+Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
+PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
+ORed together with '|' to specify one or more filters to use.
+These filters are described in more detail in the PNG specification.
+If you intend to change the filter type during the course of writing
+the image, you should start with flags set for all of the filters
+you intend to use so that libpng can initialize its internal
+structures appropriately for all of the filter types. (Note that this
+means the first row must always be adaptively filtered, because libpng
+currently does not allocate the filter buffers until png_write_row()
+is called for the first time.)
+
+ filters = PNG_FILTER_NONE | PNG_FILTER_SUB
+ PNG_FILTER_UP | PNG_FILTER_AVG |
+ PNG_FILTER_PAETH | PNG_ALL_FILTERS;
+
+ png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
+ filters);
+ The second parameter can also be
+ PNG_INTRAPIXEL_DIFFERENCING if you are
+ writing a PNG to be embedded in a MNG
+ datastream. This parameter must be the
+ same as the value of filter_method used
+ in png_set_IHDR().
+
+It is also possible to influence how libpng chooses from among the
+available filters. This is done in one or both of two ways - by
+telling it how important it is to keep the same filter for successive
+rows, and by telling it the relative computational costs of the filters.
+
+ double weights[3] = {1.5, 1.3, 1.1},
+ costs[PNG_FILTER_VALUE_LAST] =
+ {1.0, 1.3, 1.3, 1.5, 1.7};
+
+ png_set_filter_heuristics(png_ptr,
+ PNG_FILTER_HEURISTIC_WEIGHTED, 3,
+ weights, costs);
+
+The weights are multiplying factors that indicate to libpng that the
+row filter should be the same for successive rows unless another row filter
+is that many times better than the previous filter. In the above example,
+if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
+"sum of absolute differences" 1.5 x 1.3 times higher than other filters
+and still be chosen, while the NONE filter could have a sum 1.1 times
+higher than other filters and still be chosen. Unspecified weights are
+taken to be 1.0, and the specified weights should probably be declining
+like those above in order to emphasize recent filters over older filters.
+
+The filter costs specify for each filter type a relative decoding cost
+to be considered when selecting row filters. This means that filters
+with higher costs are less likely to be chosen over filters with lower
+costs, unless their "sum of absolute differences" is that much smaller.
+The costs do not necessarily reflect the exact computational speeds of
+the various filters, since this would unduly influence the final image
+size.
+
+Note that the numbers above were invented purely for this example and
+are given only to help explain the function usage. Little testing has
+been done to find optimum values for either the costs or the weights.
+
+Removing unwanted object code
+
+There are a bunch of #define's in pngconf.h that control what parts of
+libpng are compiled. All the defines end in _SUPPORTED. If you are
+never going to use a capability, you can change the #define to #undef
+before recompiling libpng and save yourself code and data space, or
+you can turn off individual capabilities with defines that begin with
+PNG_NO_.
+
+In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
+
+You can also turn all of the transforms and ancillary chunk capabilities
+off en masse with compiler directives that define
+PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
+or all four,
+along with directives to turn on any of the capabilities that you do
+want. The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra
+transformations but still leave the library fully capable of reading
+and writing PNG files with all known public chunks. Use of the
+PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
+that is incapable of reading or writing ancillary chunks. If you are
+not using the progressive reading capability, you can turn that off
+with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
+capability, which you'll still have).
+
+All the reading and writing specific code are in separate files, so the
+linker should only grab the files it needs. However, if you want to
+make sure, or if you are building a stand alone library, all the
+reading files start with pngr and all the writing files start with
+pngw. The files that don't match either (like png.c, pngtrans.c, etc.)
+are used for both reading and writing, and always need to be included.
+The progressive reader is in pngpread.c
+
+If you are creating or distributing a dynamically linked library (a .so
+or DLL file), you should not remove or disable any parts of the library,
+as this will cause applications linked with different versions of the
+library to fail if they call functions not available in your library.
+The size of the library itself should not be an issue, because only
+those sections that are actually used will be loaded into memory.
+
+Requesting debug printout
+
+The macro definition PNG_DEBUG can be used to request debugging
+printout. Set it to an integer value in the range 0 to 3. Higher
+numbers result in increasing amounts of debugging information. The
+information is printed to the "stderr" file, unless another file
+name is specified in the PNG_DEBUG_FILE macro definition.
+
+When PNG_DEBUG > 0, the following functions (macros) become available:
+
+ png_debug(level, message)
+ png_debug1(level, message, p1)
+ png_debug2(level, message, p1, p2)
+
+in which "level" is compared to PNG_DEBUG to decide whether to print
+the message, "message" is the formatted string to be printed,
+and p1 and p2 are parameters that are to be embedded in the string
+according to printf-style formatting directives. For example,
+
+ png_debug1(2, "foo=%d\n", foo);
+
+is expanded to
+
+ if (PNG_DEBUG > 2)
+ fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo);
+
+When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
+can still use PNG_DEBUG to control your own debugging:
+
+ #ifdef PNG_DEBUG
+ fprintf(stderr, ...
+ #endif
+
+When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
+having level = 0 will be printed. There aren't any such statements in
+this version of libpng, but if you insert some they will be printed.
+
+VI. MNG support
+
+The MNG specification (available at http://www.libpng.org/pub/mng) allows
+certain extensions to PNG for PNG images that are embedded in MNG datastreams.
+Libpng can support some of these extensions. To enable them, use the
+png_permit_mng_features() function:
+
+ feature_set = png_permit_mng_features(png_ptr, mask)
+
+ mask is a png_uint_32 containing the bitwise OR of the
+ features you want to enable. These include
+ PNG_FLAG_MNG_EMPTY_PLTE
+ PNG_FLAG_MNG_FILTER_64
+ PNG_ALL_MNG_FEATURES
+
+ feature_set is a png_uint_32 that is the bitwise AND of
+ your mask with the set of MNG features that is
+ supported by the version of libpng that you are using.
+
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature. The PNG datastream must be wrapped
+in a MNG datastream. As a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks. Libpng does not provide support for these
+or any other MNG chunks; your application must provide its own support for
+them. You may wish to consider using libmng (available at
+http://www.libmng.com) instead.
+
+VII. Changes to Libpng from version 0.88
+
+It should be noted that versions of libpng later than 0.96 are not
+distributed by the original libpng author, Guy Schalnat, nor by
+Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
+distributed versions 0.89 through 0.96, but rather by another member
+of the original PNG Group, Glenn Randers-Pehrson. Guy and Andreas are
+still alive and well, but they have moved on to other things.
+
+The old libpng functions png_read_init(), png_write_init(),
+png_info_init(), png_read_destroy(), and png_write_destroy() have been
+moved to PNG_INTERNAL in version 0.95 to discourage their use. These
+functions will be removed from libpng version 1.4.0.
+
+The preferred method of creating and initializing the libpng structures is
+via the png_create_read_struct(), png_create_write_struct(), and
+png_create_info_struct() because they isolate the size of the structures
+from the application, allow version error checking, and also allow the
+use of custom error handling routines during the initialization, which
+the old functions do not. The functions png_read_destroy() and
+png_write_destroy() do not actually free the memory that libpng
+allocated for these structs, but just reset the data structures, so they
+can be used instead of png_destroy_read_struct() and
+png_destroy_write_struct() if you feel there is too much system overhead
+allocating and freeing the png_struct for each image read.
+
+Setting the error callbacks via png_set_message_fn() before
+png_read_init() as was suggested in libpng-0.88 is no longer supported
+because this caused applications that do not use custom error functions
+to fail if the png_ptr was not initialized to zero. It is still possible
+to set the error callbacks AFTER png_read_init(), or to change them with
+png_set_error_fn(), which is essentially the same function, but with a new
+name to force compilation errors with applications that try to use the old
+method.
+
+Starting with version 1.0.7, you can find out which version of the library
+you are using at run-time:
+
+ png_uint_32 libpng_vn = png_access_version_number();
+
+The number libpng_vn is constructed from the major version, minor
+version with leading zero, and release number with leading zero,
+(e.g., libpng_vn for version 1.0.7 is 10007).
+
+You can also check which version of png.h you used when compiling your
+application:
+
+ png_uint_32 application_vn = PNG_LIBPNG_VER;
+
+VIII. Changes to Libpng from version 1.0.x to 1.2.x
+
+Support for user memory management was enabled by default. To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for the iTXt chunk has been enabled by default as of
+version 1.2.41.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added. However, we never got
+around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15. It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3. This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default. The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+ PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+ PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+ PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+ PNG_ASM_FLAG_MMX_READ_INTERLACE
+ PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+ PNG_ASM_FLAG_MMX_READ_FILTER_UP
+ PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+ PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+ PNG_ASM_FLAGS_INITIALIZED
+ PNG_MMX_READ_FLAGS
+ PNG_MMX_FLAGS
+ PNG_MMX_WRITE_FLAGS
+ PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+ png_get_mmx_flagmask()
+ png_set_mmx_thresholds()
+ png_get_asm_flags()
+ png_get_mmx_bitdepth_threshold()
+ png_get_mmx_rowbytes_threshold()
+ png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+These macros are deprecated:
+
+ PNG_READ_TRANSFORMS_NOT_SUPPORTED
+ PNG_PROGRESSIVE_READ_NOT_SUPPORTED
+ PNG_NO_SEQUENTIAL_READ_SUPPORTED
+ PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
+ PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+ PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+They have been replaced, respectively, by:
+
+ PNG_NO_READ_TRANSFORMS
+ PNG_NO_PROGRESSIVE_READ
+ PNG_NO_SEQUENTIAL_READ
+ PNG_NO_WRITE_TRANSFORMS
+ PNG_NO_READ_ANCILLARY_CHUNKS
+ PNG_NO_WRITE_ANCILLARY_CHUNKS
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+ png_check_sig(sig, num)
+was replaced with
+ !png_sig_cmp(sig, 0, num)
+It has been deprecated since libpng-0.90.
+
+The function
+ png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+ png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+IX. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states by adding png_ptr member io_state
+and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
+input transforms.
+
+Checking for and reporting of errors in the IHDR chunk is more thorough.
+
+Support for global arrays was removed, to improve thread safety.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+Typecasted NULL definitions such as
+ #define png_voidp_NULL (png_voidp)NULL
+were eliminated. If you used these in your application, just use
+NULL instead.
+
+The png_struct and info_struct members "trans" and "trans_values" were
+changed to "trans_alpha" and "trans_color", respectively.
+
+The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
+were removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+The PNG_LEGACY_SUPPORTED macro was eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed. They have been deprecated since libpng-0.95.
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9. Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the obsolete png_check_sig(), png_memcpy_check(), and
+png_memset_check() functions. Instead use !png_sig_cmp(), memcpy(),
+and memset(), respectively.
+
+The function png_set_gray_1_2_4_to_8() was removed. It has been
+deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
+png_set_expand_gray_1_2_4_to_8() because the former function also
+expanded palette images.
+
+Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
+were added and are used by default instead of the corresponding
+functions. Unfortunately,
+from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+
+We changed the prototype for png_malloc() from
+ png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+ png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+This also applies to the prototype for the user replacement malloc_fn().
+
+The png_calloc() function was added and is used in place of
+of "png_malloc(); memset();" except in the case in png_read_png()
+where the array consists of pointers; in this case a "for" loop is used
+after the png_malloc() to set the pointers to NULL, to give robust.
+behavior in case the application runs out of memory part-way through
+the process.
+
+We changed the prototypes of png_get_compression_buffer_size() and
+png_set_compression_buffer_size() to work with png_size_t instead of
+png_uint_32.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+The png_zalloc() function no longer zeroes out the memory that it
+allocates.
+
+Support for dithering was disabled by default in libpng-1.4.0, because
+been well tested and doesn't actually "dither". The code was not
+removed, however, and could be enabled by building libpng with
+PNG_READ_DITHER_SUPPORTED defined. In libpng-1.4.2, this support
+was reenabled, but the function was renamed png_set_quantize() to
+reflect more accurately what it actually does. At the same time,
+the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
+PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
+was renamed to PNG_READ_QUANTIZE_SUPPORTED.
+
+We removed the trailing '.' from the warning and error messages.
+
+X. Changes to Libpng from version 1.4.x to 1.5.x
+
+From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+
+A. Changes that affect users of libpng
+
+There are no substantial API changes between the non-deprecated parts of
+the 1.4.5 API and the 1.5.0 API, however the ability to directly access
+the main libpng control structures, png_struct and png_info, deprecated
+in earlier versions of libpng, has been completely removed from
+libpng 1.5.
+
+We no longer include zlib.h in png.h. Applications that need access
+to information in zlib.h will need to add the '#include "zlib.h"'
+directive. It does not matter whether it is placed prior to or after
+the '"#include png.h"' directive.
+
+We moved the png_strcpy(), png_strncpy(), png_strlen(), png_memcpy(),
+png_memcmp(), png_sprintf, and png_memcpy() macros into a private
+header file (pngpriv.h) that is not accessible to applications.
+
+In png_get_iCCP, the type of "profile" was changed from png_charpp
+to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
+
+There are changes of form in png.h, including new and changed macros to
+declare
+parts of the API. Some API functions with arguments that are pointers to
+data not modified within the function have been corrected to declare
+these arguments with PNG_CONST.
+
+Much of the internal use of C macros to control the library build has also
+changed and some of this is visible in the exported header files, in
+particular the use of macros to control data and API elements visible
+during application compilation may require significant revision to
+application code. (It is extremely rare for an application to do this.)
+
+Any program that compiled against libpng 1.4 and did not use deprecated
+features or access internal library structures should compile and work
+against libpng 1.5.
+
+libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
+interlaced images. The macros return the number of rows and columns in
+each pass and information that can be used to de-interlace and (if
+absolutely necessary) interlace an image.
+
+libpng 1.5.0 adds an API png_longjmp(png_ptr, value). This API calls
+the application provided png_longjmp_ptr on the internal, but application
+initialized, jmpbuf. It is provided as a convenience to avoid the need
+to use the png_jmpbuf macro, which had the unnecessary side effect of
+resetting the internal png_longjmp_ptr value.
+
+libpng 1.5.0 includes a complete fixed point API. By default this is
+present along with the corresponding floating point API. In general the
+fixed point API is faster and smaller than the floating point one because
+the PNG file format used fixed point, not floating point. This applies
+even if the library uses floating point in internal calculations. A new
+macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
+uses floating point arithmetic (the default) or fixed point arithmetic
+internally for performance critical calculations such as gamma correction.
+In some cases, the gamma calculations may produce slightly different
+results. This has changed the results in png_rgb_to_gray and in alpha
+composition (png_set_background for example). This applies even if the
+original image was already linear (gamma == 1.0) and, therefore, it is
+not necessary to linearize the image. This is because libpng has *not*
+been changed to optimize that case correctly, yet.
+
+Fixed point support for the sCAL chunk comes with an important caveat;
+the sCAL specification uses a decimal encoding of floating point values
+and the accuracy of PNG fixed point values is insufficient for
+representation of these values. Consequently a "string" API
+(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
+arbitrary sCAL chunks in the absence of either the floating point API or
+internal floating point calculations.
+
+Applications no longer need to include the optional distribution header
+file pngusr.h or define the corresponding macros during application
+build in order to see the correct variant of the libpng API. From 1.5.0
+application code can check for the corresponding _SUPPORTED macro:
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+ /* code that uses the inch conversion APIs. */
+#endif
+
+This macro will only be defined if the inch conversion functions have been
+compiled into libpng. The full set of macros, and whether or not support
+has been compiled in, are available in the header file pnglibconf.h.
+This header file is specific to the libpng build. Notice that prior to
+1.5.0 the _SUPPORTED macros would always have the default definition unless
+reset by pngusr.h or by explicit settings on the compiler command line.
+These settings may produce compiler warnings or errors in 1.5.0 because
+of macro redefinition.
+
+From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32. libpng 1.5.0
+is consistent with the implementation in 1.4.5 and 1.2.x (where the macro
+did not exist.)
+
+Applications can now choose whether to use these macros or to call the
+corresponding function by defining PNG_USE_READ_MACROS or
+PNG_NO_USE_READ_MACROS before including png.h. Notice that this is
+only supported from 1.5.0 -defining PNG_NO_USE_READ_MACROS prior to 1.5.0
+ will lead to a link failure.
+
+B. Changes to the build and configuration of libpng
+
+Details of internal changes to the library code can be found in the CHANGES
+file. These will be of no concern to the vast majority of library users or
+builders, however the few who configure libpng to a non-default feature
+set may need to change how this is done.
+
+There should be no need for library builders to alter build scripts if
+these use the distributed build support - configure or the makefiles -
+however users of the makefiles may care to update their build scripts
+to build pnglibconf.h where the corresponding makefile does not do so.
+
+Building libpng with a non-default configuration has changed completely.
+The old method using pngusr.h should still work correctly even though the
+way pngusr.h is used in the build has been changed, however library
+builders will probably want to examine the changes to take advantage of
+new capabilities and to simplify their build system.
+
+B.1 Specific changes to library configuration capabilities
+
+The library now supports a complete fixed point implementation and can
+thus be used on systems which have no floating point support or very
+limited or slow support. Previously gamma correction, an essential part
+of complete PNG support, required reasonably fast floating point.
+
+As part of this the choice of internal implementation has been made
+independent of the choice of fixed versus floating point APIs and all the
+missing fixed point APIs have been implemented.
+
+The exact mechanism used to control attributes of API functions has
+changed. A single set of operating system independent macro definitions
+is used and operating system specific directives are defined in
+pnglibconf.h
+
+As part of this the mechanism used to choose procedure call standards on
+those systems that allow a choice has been changed. At present this only
+affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
+running on Intel processors. As before PNGAPI is defined where required
+to control the exported API functions; however, two new macros, PNGCBAPI
+and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
+(PNGCAPI) for functions that must match a C library prototype (currently
+only png_longjmp_ptr, which must match the C longjmp function.) The new
+approach is documented in pngconf.h
+
+Despite these changes libpng 1.5.0 only supports the native C function
+calling standard on those platforms tested so far (__cdecl on Microsoft
+Windows). This is because the support requirements for alternative
+calling conventions seem to no longer exist. Developers who find it
+necessary to set PNG_API_RULE to 1 should advise the mailing list
+(png-mng-implement) of this and library builders who use Openwatcom and
+therefore set PNG_API_RULE to 2 should also contact the mailing list.
+
+A new test program, pngvalid, is provided in addition to pngtest.
+pngvalid validates the arithmetic accuracy of the gamma correction
+calculations and includes a number of validations of the file format.
+A subset of the full range of tests is run when "make check" is done
+(in the 'configure' build.) pngvalid also allows total allocated memory
+usage to be evaluated and performs additional memory overwrite validation.
+
+Many changes to individual feature macros have been made. The following
+are the changes most likely to be noticed by library builders who
+configure libpng:
+
+1) All feature macros now have consistent naming:
+
+#define PNG_NO_feature turns the feature off
+#define PNG_feature_SUPPORTED turns the feature on
+
+pnglibconf.h contains one line for each feature macro which is either:
+
+#define PNG_feature_SUPPORTED
+
+if the feature is supported or:
+
+/*#undef PNG_feature_SUPPORTED*/
+
+if it is not. Library code consistently checks for the 'SUPPORTED' macro.
+It does not, and should not, check for the 'NO' macro which will not
+normally be defined even if the feature is not supported.
+
+Compatibility with the old names is provided as follows:
+
+PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
+
+And the following definitions disable the corresponding feature:
+
+PNG_SETJMP_NOT_SUPPORTED disables SETJMP
+PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
+PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
+PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
+PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
+PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
+
+Library builders should remove use of the above, inconsistent, names.
+
+2) Warning and error message formatting was previously conditional on
+the STDIO feature. The library has been changed to use the
+CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
+the library no longer uses the printf(3) functions, even though the
+default read/write implementations use (FILE) style stdio.h functions.
+
+3) Three feature macros now control the fixed/floating point decisions:
+
+PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
+
+PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
+practice these are normally required internally anyway (because the PNG
+file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
+merely stops the function from being exported.
+
+PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
+point implementation or the fixed point one. Typically the fixed point
+implementation is larger and slower than the floating point implementation
+on a system that supports floating point, however it may be faster on a
+system which lacks floating point hardware and therefore uses a software
+emulation.
+
+4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the
+functions to read and write ints to be disabled independently of
+PNG_USE_READ_MACROS, which allows libpng to be built with the functions
+even though the default is to use the macros - this allows applications
+to choose at app buildtime whether or not to use macros (previously
+impossible because the functions weren't in the default build.)
+
+B.2 Changes to the configuration mechanism
+
+Prior to libpng-1.5.0 library builders who needed to configure libpng
+had either to modify the exported pngconf.h header file to add system
+specific configuration or had to write feature selection macros into
+pngusr.h and cause this to be included into pngconf.h by defining
+PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
+application built without PNG_USER_CONFIG defined would see the
+unmodified, default, libpng API and thus would probably fail to link.
+
+These mechanisms still work in the configure build and in any makefile
+build that builds pnglibconf.h although the feature selection macros
+have changed somewhat as described above. In 1.5.0, however, pngusr.h is
+processed only once, when the exported header file pnglibconf.h is built.
+pngconf.h no longer includes pngusr.h, therefore it is ignored after the
+build of pnglibconf.h and it is never included in an application build.
+
+The rarely used alternative of adding a list of feature macros to the
+CFLAGS setting in the build also still works, however the macros will be
+copied to pnglibconf.h and this may produce macro redefinition warnings
+when the individual C files are compiled.
+
+All configuration now only works if pnglibconf.h is built from
+scripts/pnglibconf.dfa. This requires the program awk. Brian Kernighan
+(the original author of awk) maintains C source code of that awk and this
+and all known later implementations (often called by subtly different
+names - nawk and gawk for example) are adequate to build pnglibconf.h.
+The Sun Microsystems (now Oracle) program 'awk' is an earlier version
+and does not work, this may also apply to other systems that have a
+functioning awk called 'nawk'.
+
+Configuration options are now documented in scripts/pnglibconf.dfa. This
+file also includes dependency information that ensures a configuration is
+consistent; that is, if a feature is switched off dependent features are
+also removed. As a recommended alternative to using feature macros in
+pngusr.h a system builder may also define equivalent options in pngusr.dfa
+(or, indeed, any file) and add that to the configuration by setting
+DFA_XTRA to the file name. The makefiles in contrib/pngminim illustrate
+how to do this, and a case where pngusr.h is still required.
+
+XI. Detecting libpng
+
+The png_get_io_ptr() function has been present since libpng-0.88, has never
+changed, and is unaffected by conditional compilation macros. It is the
+best choice for use in configure scripts for detecting the presence of any
+libpng version since 0.88. In an autoconf "configure.in" you could use
+
+ AC_CHECK_LIB(png, png_get_io_ptr, ...
+
+XII. Source code repository
+
+Since about February 2009, version 1.2.34, libpng has been under "git" source
+control. The git repository was built from old libpng-x.y.z.tar.gz files
+going back to version 0.70. You can access the git repository (read only)
+at
+
+ git://libpng.git.sourceforge.net/gitroot/libpng
+
+or you can browse it via "gitweb" at
+
+ http://libpng.git.sourceforge.net/git/gitweb.cgi?p=libpng
+
+Patches can be sent to glennrp at users.sourceforge.net or to
+png-mng-implement at lists.sourceforge.net or you can upload them to
+the libpng bug tracker at
+
+ http://libpng.sourceforge.net
+
+We also accept patches built from the tar or zip distributions, and
+simple verbal discriptions of bug fixes, reported either to the
+SourceForge bug tracker or to the png-mng-implement at lists.sf.net
+mailing list.
+
+XIII. Coding style
+
+Our coding style is similar to the "Allman" style, with curly
+braces on separate lines:
+
+ if (condition)
+ {
+ action;
+ }
+
+ else if (another condition)
+ {
+ another action;
+ }
+
+The braces can be omitted from simple one-line actions:
+
+ if (condition)
+ return (0);
+
+We use 3-space indentation, except for continued statements which
+are usually indented the same as the first line of the statement
+plus four more spaces.
+
+For macro definitions we use 2-space indentation, always leaving the "#"
+in the first column.
+
+ #ifndef PNG_NO_FEATURE
+ # ifndef PNG_FEATURE_SUPPORTED
+ # define PNG_FEATURE_SUPPORTED
+ # endif
+ #endif
+
+Comments appear with the leading "/*" at the same indentation as
+the statement that follows the comment:
+
+ /* Single-line comment */
+ statement;
+
+ /* This is a multiple-line
+ * comment.
+ */
+ statement;
+
+Very short comments can be placed after the end of the statement
+to which they pertain:
+
+ statement; /* comment */
+
+We don't use C++ style ("//") comments. We have, however,
+used them in the past in some now-abandoned MMX assembler
+code.
+
+Functions and their curly braces are not indented, and
+exported functions are marked with PNGAPI:
+
+ /* This is a public function that is visible to
+ * application programmers. It does thus-and-so.
+ */
+ void PNGAPI
+ png_exported_function(png_ptr, png_info, foo)
+ {
+ body;
+ }
+
+The prototypes for all exported functions appear in png.h,
+above the comment that says
+
+ /* Maintainer: Put new public prototypes here ... */
+
+We mark all non-exported functions with "/* PRIVATE */"":
+
+ void /* PRIVATE */
+ png_non_exported_function(png_ptr, png_info, foo)
+ {
+ body;
+ }
+
+The prototypes for non-exported functions (except for those in
+pngtest) appear in
+pngpriv.h
+above the comment that says
+
+ /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
+
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG_". We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
+We put a space after each comma and after each semicolon
+in "for" statements, and we put spaces before and after each
+C binary operator and after "for" or "while", and before
+"?". We don't put a space between a typecast and the expression
+being cast, nor do we put one between a function name and the
+left parenthesis that follows it:
+
+ for (i = 2; i > 0; --i)
+ y[i] = a(x) + (int)b;
+
+We prefer #ifdef and #ifndef to #if defined() and if !defined()
+when there is only one macro being tested.
+
+We do not use the TAB character for indentation in the C sources.
+
+Lines do not exceed 80 characters.
+
+Other rules can be inferred by inspecting the libpng source.
+
+XIV. Y2K Compliance in libpng
+
+February 3, 2011
+
+Since the PNG Development group is an ad-hoc body, we can't make
+an official declaration.
+
+This is your unofficial assurance that libpng from version 0.71 and
+upward through 1.5.1 are Y2K compliant. It is my belief that earlier
+versions were also Y2K compliant.
+
+Libpng only has three year fields. One is a 2-byte unsigned integer that
+will hold years up to 65535. The other two hold the date in text
+format, and will hold years up to 9999.
+
+The integer is
+ "png_uint_16 year" in png_time_struct.
+
+The strings are
+ "png_charp time_buffer" in png_struct and
+ "near_time_buffer", which is a local character string in png.c.
+
+There are seven time-related functions:
+
+ png_convert_to_rfc_1123() in png.c
+ (formerly png_convert_to_rfc_1152() in error)
+ png_convert_from_struct_tm() in pngwrite.c, called
+ in pngwrite.c
+ png_convert_from_time_t() in pngwrite.c
+ png_get_tIME() in pngget.c
+ png_handle_tIME() in pngrutil.c, called in pngread.c
+ png_set_tIME() in pngset.c
+ png_write_tIME() in pngwutil.c, called in pngwrite.c
+
+All appear to handle dates properly in a Y2K environment. The
+png_convert_from_time_t() function calls gmtime() to convert from system
+clock time, which returns (year - 1900), which we properly convert to
+the full 4-digit year. There is a possibility that applications using
+libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
+function, or that they are incorrectly passing only a 2-digit year
+instead of "year - 1900" into the png_convert_from_struct_tm() function,
+but this is not under our control. The libpng documentation has always
+stated that it works with 4-digit years, and the APIs have been
+documented as such.
+
+The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
+integer to hold the year, and can hold years as large as 65535.
+
+zlib, upon which libpng depends, is also Y2K compliant. It contains
+no date-related code.
+
+
+ Glenn Randers-Pehrson
+ libpng maintainer
+ PNG Development Group
diff --git a/src/3rdparty/libpng/libpng.3 b/src/3rdparty/libpng/libpng.3
new file mode 100644
index 0000000000..ecc42777bf
--- /dev/null
+++ b/src/3rdparty/libpng/libpng.3
@@ -0,0 +1,5376 @@
+.TH LIBPNG 3 "February 3, 2011"
+.SH NAME
+libpng \- Portable Network Graphics (PNG) Reference Library 1.5.1
+.SH SYNOPSIS
+\fI\fB
+
+\fB#include <png.h>\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_access_version_number \fI(void\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_calloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_chunk_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_structp png_create_read_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_structp png_create_read_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask)\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_destroy_write_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_err (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_bKGD (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fI*background\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_channels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_cHRM (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*white_x\fP\fB, double \fP\fI*white_y\fP\fB, double \fP\fI*red_x\fP\fB, double \fP\fI*red_y\fP\fB, double \fP\fI*green_x\fP\fB, double \fP\fI*green_y\fP\fB, double \fP\fI*blue_x\fP\fB, double \fI*blue_y\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_cHRM_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*white_x\fP\fB, png_uint_32 \fP\fI*white_y\fP\fB, png_uint_32 \fP\fI*red_x\fP\fB, png_uint_32 \fP\fI*red_y\fP\fB, png_uint_32 \fP\fI*green_x\fP\fB, png_uint_32 \fP\fI*green_y\fP\fB, png_uint_32 \fP\fI*blue_x\fP\fB, png_uint_32 \fI*blue_y\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_chunk_cache_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fI\fB
+
+\fBpng_alloc_size_t png_get_chunk_malloc_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_color_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_compression_buffer_size (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_compression_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_copyright (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_current_row_number \fI(png_const_structp\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_current_pass_number \fI(png_const_structp\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_get_error_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_filter_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_gAMA (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fI*file_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_gAMA_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fI*int_file_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_header_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_header_version (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_hIST (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_iCCP (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_bytepp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*width\fP\fB, png_uint_32 \fP\fI*height\fP\fB, int \fP\fI*bit_depth\fP\fB, int \fP\fI*color_type\fP\fB, int \fP\fI*interlace_type\fP\fB, int \fP\fI*compression_type\fP\fB, int \fI*filter_type\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_image_height (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_image_width (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_interlace_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_const_bytep png_get_io_chunk_name (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_io_chunk_type (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_io_state (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_libpng_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_get_mem_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_oFFs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_pCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fI*purpose\fP\fB, png_int_32 \fP\fI*X0\fP\fB, png_int_32 \fP\fI*X1\fP\fB, int \fP\fI*type\fP\fB, int \fP\fI*nparams\fP\fB, png_charp \fP\fI*units\fP\fB, png_charpp \fI*params\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_pHYs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fI\fB
+
+\fBfloat png_get_pixel_aspect_ratio (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_pHYs_dpi (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_fixed_point png_get_pixel_aspect_ratio_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_get_progressive_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_PLTE (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fI*palette\fP\fB, int \fI*num_palette\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_byte png_get_rgb_to_gray_status (png_const_structp \fIpng_ptr)
+
+\fBpng_uint_32 png_get_rowbytes (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_bytepp png_get_rows (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_sBIT (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fI*sig_bit\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_get_sCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, double* \fP\fIwidth\fP\fB, double* \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_get_sCAL_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_fixed_pointp \fP\fIwidth\fP\fB, png_fixed_pointp \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_get_sCAL_s (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_charpp \fP\fIwidth\fP\fB, png_charpp \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_bytep png_get_signature (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_sPLT (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fI*splt_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_sRGB (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int \fI*file_srgb_intent\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_text (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fI*text_ptr\fP\fB, int \fI*num_text\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_tIME (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fI*mod_time\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_tRNS (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans_alpha\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_color\fP\fB);\fP
+
+\fI\fB
+
+\fB/* This function is really an inline macro. \fI*/
+
+\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_uint_31 (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIbuf\fP\fB);\fP
+
+\fI\fB
+
+\fB/* This function is really an inline macro. \fI*/
+
+\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_unknown_chunks (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkpp \fIunknowns\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_get_user_chunk_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_user_height_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_get_user_transform_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_user_width_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_valid (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIflag\fP\fB);\fP
+
+\fI\fB
+
+\fBfloat png_get_x_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_fixed_point png_get_x_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_int_32 png_get_x_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_int_32 png_get_x_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_x_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_x_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBfloat png_get_y_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_fixed_point png_get_y_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_int_32 png_get_y_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_int_32 png_get_y_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_y_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_y_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_size\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_size_t png_process_data_pause \fP\fI(png_structp\fP\fB, int \fIsave\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_process_data_skip \fI(png_structp\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_bytepp \fP\fIdisplay_row\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_background_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, png_uint_32 \fIbackground_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_benign_errors (png_structp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_bgr (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fIbackground\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_chunk_cache_max (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIuser_chunk_cache_max\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_crc_action (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcrit_action\fP\fB, int \fIancil_action\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_error_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarning_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_expand (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_expand_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_filler (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_filter (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImethod\fP\fB, int \fIfilters\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_filter_heuristics (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_doublep \fP\fIfilter_weights\fP\fB, png_doublep \fIfilter_costs\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_filter_heuristics_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_fixed_point_p \fP\fIfilter_weights\fP\fB, png_fixed_point_p \fIfilter_costs\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_flush (png_structp \fP\fIpng_ptr\fP\fB, int \fInrows\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_gamma (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIscreen_gamma\fP\fB, double \fIdefault_file_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_gamma_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIscreen_gamma\fP\fB, png_uint_32 \fIdefault_file_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIfile_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_gray_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_const_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_const_bytep \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_set_interlace_handling (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_invalid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fImask\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_invert_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_invert_mono (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIinterlace_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fIfilter_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP
+
+\fI\fB
+
+\fBjmp_buf* png_set_longjmp_fn (png_structp \fP\fIpng_ptr\fP\fB, png_longjmp_ptr \fP\fIlongjmp_fn\fP\fB, size_t \fIjmp_buf_size\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_chunk_malloc_max (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIuser_chunk_cache_max\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_compression_buffer_size (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_mem_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_packing (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_packswap (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_palette_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIres_x\fP\fB, png_uint_32 \fP\fIres_y\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_progressive_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIprogressive_ptr\fP\fB, png_progressive_info_ptr \fP\fIinfo_fn\fP\fB, png_progressive_row_ptr \fP\fIrow_fn\fP\fB, png_progressive_end_ptr \fIend_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_quantize (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_quantize\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fIread_data_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_read_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_read_status_ptr \fIread_row_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_read_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIread_user_transform_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_rgb_to_gray (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIerror_action\fP\fB, double \fP\fIred\fP\fB, double \fIgreen\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_rgb_to_gray_fixed (png_structp \fP\fIpng_ptr\fP\fB, int error_action png_uint_32 \fP\fIred\fP\fB, png_uint_32 \fIgreen\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytepp \fIrow_pointers\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fIsig_bit\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sCAL_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_fixed_point \fP\fIwidth\fP\fB, png_fixed_point \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_shift (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fItrue_bits\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sig_bytes (png_structp \fP\fIpng_ptr\fP\fB, int \fInum_bytes\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fP\fIsplt_ptr\fP\fB, int \fInum_spalettes\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_sRGB_gAMA_and_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_strip_16 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_strip_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_strip_error_numbers (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIstrip_mode\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_swap_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fItext_ptr\fP\fB, int \fInum_text\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans_alpha\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_color\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_tRNS_to_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_unknown_chunk_location (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIchunk\fP\fB, int \fIlocation\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_user_limits (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIuser_width_max\fP\fB, png_uint_32 \fIuser_height_max\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_user_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_transform_ptr\fP\fB, int \fP\fIuser_transform_depth\fP\fB, int \fIuser_transform_channels\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_write_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fP\fIwrite_data_fn\fP\fB, png_flush_ptr \fIoutput_flush_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_write_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_write_status_ptr \fIwrite_row_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, png_size_t \fP\fIstart\fP\fB, png_size_t \fInum_to_check\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_chunk_start (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_flush (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_info_before_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoidpf png_zalloc (voidpf \fP\fIpng_ptr\fP\fB, uInt \fP\fIitems\fP\fB, uInt \fIsize\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_zfree (voidpf \fP\fIpng_ptr\fP\fB, voidpf \fIptr\fP\fB);\fP
+
+\fI\fB
+
+.SH DESCRIPTION
+The
+.I libpng
+library supports encoding, decoding, and various manipulations of
+the Portable Network Graphics (PNG) format image files. It uses the
+.IR zlib(3)
+compression library.
+Following is a copy of the libpng-manual.txt file that accompanies libpng.
+.SH LIBPNG.TXT
+libpng-manual.txt - A description on how to use and modify libpng
+
+ libpng version 1.5.1 - February 3, 2011
+ Updated and distributed by Glenn Randers-Pehrson
+ <glennrp at users.sourceforge.net>
+ Copyright (c) 1998-2011 Glenn Randers-Pehrson
+
+ This document is released under the libpng license.
+ For conditions of distribution and use, see the disclaimer
+ and license in png.h
+
+ Based on:
+
+ libpng versions 0.97, January 1998, through 1.5.1 - February 3, 2011
+ Updated and distributed by Glenn Randers-Pehrson
+ Copyright (c) 1998-2011 Glenn Randers-Pehrson
+
+ libpng 1.0 beta 6 version 0.96 May 28, 1997
+ Updated and distributed by Andreas Dilger
+ Copyright (c) 1996, 1997 Andreas Dilger
+
+ libpng 1.0 beta 2 - version 0.88 January 26, 1996
+ For conditions of distribution and use, see copyright
+ notice in png.h. Copyright (c) 1995, 1996 Guy Eric
+ Schalnat, Group 42, Inc.
+
+ Updated/rewritten per request in the libpng FAQ
+ Copyright (c) 1995, 1996 Frank J. T. Wojcik
+ December 18, 1995 & January 20, 1996
+
+.SH I. Introduction
+
+This file describes how to use and modify the PNG reference library
+(known as libpng) for your own use. There are five sections to this
+file: introduction, structures, reading, writing, and modification and
+configuration notes for various special platforms. In addition to this
+file, example.c is a good starting point for using the library, as
+it is heavily commented and should include everything most people
+will need. We assume that libpng is already installed; see the
+INSTALL file for instructions on how to install libpng.
+
+For examples of libpng usage, see the files "example.c", "pngtest.c",
+and the files in the "contrib" directory, all of which are included in
+the libpng distribution.
+
+Libpng was written as a companion to the PNG specification, as a way
+of reducing the amount of time and effort it takes to support the PNG
+file format in application programs.
+
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2003 (E)) at
+<http://www.w3.org/TR/2003/REC-PNG-20031110/
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<http://www.libpng.org/pub/png/documents/>. It is technically equivalent
+to the PNG specification (second edition) but has some additional material.
+
+The PNG-1.0 specification is available
+as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a
+W3C Recommendation <http://www.w3.org/TR/REC.png.html>.
+
+Some additional chunks are described in the special-purpose public chunks
+documents at <http://www.libpng.org/pub/png/documents/>.
+
+Other information
+about PNG, and the latest version of libpng, can be found at the PNG home
+page, <http://www.libpng.org/pub/png/>.
+
+Most users will not have to modify the library significantly; advanced
+users may want to modify it more. All attempts were made to make it as
+complete as possible, while keeping the code easy to understand.
+Currently, this library only supports C. Support for other languages
+is being considered.
+
+Libpng has been designed to handle multiple sessions at one time,
+to be easily modifiable, to be portable to the vast majority of
+machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
+to use. The ultimate goal of libpng is to promote the acceptance of
+the PNG file format in whatever way possible. While there is still
+work to be done (see the TODO file), libpng should cover the
+majority of the needs of its users.
+
+Libpng uses zlib for its compression and decompression of PNG files.
+Further information about zlib, and the latest version of zlib, can
+be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
+The zlib compression utility is a general purpose utility that is
+useful for more than PNG files, and can be used without libpng.
+See the documentation delivered with zlib for more details.
+You can usually find the source files for the zlib utility wherever you
+find the libpng source files.
+
+Libpng is thread safe, provided the threads are using different
+instances of the structures. Each thread should have its own
+png_struct and png_info instances, and thus its own image.
+Libpng does not protect itself against two threads using the
+same instance of a structure.
+
+.SH II. Structures
+
+There are two main structures that are important to libpng, png_struct
+and png_info. Both are internal structures that are no longer exposed
+in the libpng interface (as of libpng 1.5.0).
+
+The png_info structure is designed to provide information about the
+PNG file. At one time, the fields of png_info were intended to be
+directly accessible to the user. However, this tended to cause problems
+with applications using dynamically loaded libraries, and as a result
+a set of interface functions for png_info (the png_get_*() and png_set_*()
+functions) was developed.
+
+The png_struct structure is the object used by the library to decode a
+single image. As of 1.5.0 this structure is also not exposed.
+
+Almost all libpng APIs require a pointer to a png_struct as the first argument.
+Many (in particular the png_set and png_get APIs) also require a pointer
+to png_info as the second argument. Some application visible macros
+defined in png.h designed for basic data access (reading and writing
+integers in the PNG format) break this rule, but it's almost always safe
+to assume that a (png_struct*) has to be passed to call an API function.
+
+The png.h header file is an invaluable reference for programming with libpng.
+And while I'm on the topic, make sure you include the libpng header file:
+
+#include <png.h>
+
+.SS Types
+
+The png.h header file defines a number of integral types used by the
+APIs. Most of these are fairly obvious; for example types corresponding
+to integers of particular sizes and types for passing color values.
+
+One exception is how non-integral numbers are handled. For application
+convenience most APIs that take such numbers have C (double) arguments,
+however internally PNG, and libpng, use 32 bit signed integers and encode
+the value by multiplying by 100,000. As of libpng 1.5.0 a convenience
+macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
+which is simply (png_int_32).
+
+All APIs that take (double) arguments also have an matching API that
+takes the corresponding fixed point integer arguments. The fixed point
+API has the same name as the floating point one with _fixed appended.
+The actual range of values permitted in the APIs is frequently less than
+the full range of (png_fixed_point) (-21474 to +21474). When APIs require
+a non-negative argument the type is recorded as png_uint_32 above. Consult
+the header file and the text below for more information.
+
+Special care must be take with sCAL chunk handling because the chunk itself
+uses non-integral values encoded as strings containing decimal floating point
+numbers. See the comments in the header file.
+
+.SS Configuration
+
+The main header file function declarations are frequently protected by C
+preprocessing directives of the form:
+
+ #ifdef PNG_feature_SUPPORTED
+ declare-function
+ #endif
+
+The library can be built without support for these APIs, although a
+standard build will have all implemented APIs. Application programs
+should check the feature macros before using an API for maximum
+portability. From libpng 1.5.0 the feature macros set during the build
+of libpng are recorded in the header file "pnglibconf.h" and this file
+is always included by png.h.
+
+If you don't need to change the library configuration from the default skip to
+the next section ("Reading").
+
+Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
+of the build project files in the 'projects' directory simply copy
+scripts/pnglibconf.h.prebuilt to pnglibconf.h. This means that these build
+systems do not permit easy auto-configuration of the library - they only
+support the default configuration.
+
+The easiest way to make minor changes to the libpng configuration when
+auto-configuration is supported is to add definitions to the command line
+using (typically) CPPFLAGS. For example:
+
+CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
+
+will change the internal libpng math implementation for gamma correction and
+other arithmetic calculations to fixed point, avoiding the need for fast
+floating point support. The result can be seen in the generated pnglibconf.h -
+make sure it contains the changed feature macro setting.
+
+If you need to make more extensive configuration changes - more than one or two
+feature macro settings - you can either add -DPNG_USER_CONFIG to the build
+command line and put a list of feature macro settings in pngusr.h or you can set
+DFA_XTRA (a makefile variable) to a file containing the same information in the
+form of 'option' settings.
+
+A. Changing pnglibconf.h
+
+A variety of methods exist to build libpng. Not all of these support
+reconfiguration of pnglibconf.h. To reconfigure pnglibconf.h it must either be
+rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
+
+Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt and changing
+the lines defining the supported features, paying very close attention to the
+'option' information in scripts/pnglibconf.dfa that describes those features and
+their requirements. This is easy to get wrong.
+
+B. Configuration using DFA_XTRA
+
+Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
+variant such as 'nawk' or 'gawk', is available. The configure build will
+automatically find an appropriate awk and build pnglibconf.h.
+scripts/pnglibconf.mak contains a set of make rules for doing the same thing if
+configure is not used, and many of the makefiles in the scripts directory use
+this approach.
+
+When rebuilding simply write new file containing changed options and set
+DFA_XTRA to the name of this file. This causes the build to append the new file
+to the end of scripts/pnglibconf.dfa. pngusr.dfa should contain lines of the
+following forms:
+
+everything = off
+
+This turns all optional features off. Include it at the start of pngusr.dfa to
+make it easier to build a minimal configuration. You will need to turn at least
+some features on afterward to enable either reading or writing code, or both.
+
+option feature on
+option feature off
+
+Enable or disable a single feature. This will automatically enable other
+features required by a feature that is turned on or disable other features that
+require a feature which is turned off. Conflicting settings will cause an error
+message to be emitted by awk.
+
+setting feature default value
+
+Changes the default value of setting 'feature' to 'value'. There are a small
+number of settings listed at the top of pnglibconf.h, they are documented in the
+source code. Most of these values have performance implications for the library
+but most of them have no visible effect on the API. Some can also be overridden
+from the API.
+
+C. Configuration using PNG_USR_CONFIG
+
+If -DPNG_USR_CONFIG is added to the CFLAGS when pnglibconf.h is built the file
+pngusr.h will automatically be included before the options in
+scripts/pnglibconf.dfa are processed. pngusr.h should contain only macro
+definitions turning features on or off or setting settings.
+
+Apart from the global setting "everything = off" all the options listed above
+can be set using macros in pngusr.h:
+
+#define PNG_feature_SUPPORTED
+
+is equivalent to:
+
+option feature on
+
+#define PNG_NO_feature
+
+is equivalent to:
+
+option feature off
+
+#define PNG_feature value
+
+is equivalent to:
+
+setting feature default value
+
+Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
+pngusr file you supply override the contents of scripts/pnglibconf.dfa
+
+If confusing or incomprehensible behavior results it is possible to
+examine the intermediate file pnglibconf.dfn to find the full set of
+dependency information for each setting and option. Simply locate the
+feature in the file and read the C comments that precede it.
+
+.SH III. Reading
+
+We'll now walk you through the possible functions to call when reading
+in a PNG file sequentially, briefly explaining the syntax and purpose
+of each one. See example.c and png.h for more detail. While
+progressive reading is covered in the next section, you will still
+need some of the functions discussed in this section to read a PNG
+file.
+
+.SS Setup
+
+You will want to do the I/O initialization(*) before you get into libpng,
+so if it doesn't work, you don't have much to undo. Of course, you
+will also want to insure that you are, in fact, dealing with a PNG
+file. Libpng provides a simple check to see if a file is a PNG file.
+To use it, pass in the first 1 to 8 bytes of the file to the function
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
+
+If you are intending to keep the file pointer open for use in libpng,
+you must ensure you don't read more than 8 bytes from the beginning
+of the file, and you also have to make a call to png_set_sig_bytes_read()
+with the number of bytes you read from the beginning. Libpng will
+then only check the bytes (if any) that your program didn't read.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions. See the discussion under
+Customizing libpng.
+
+
+ FILE *fp = fopen(file_name, "rb");
+ if (!fp)
+ {
+ return (ERROR);
+ }
+
+ fread(header, 1, number, fp);
+ is_png = !png_sig_cmp(header, 0, number);
+
+ if (!is_png)
+ {
+ return (NOT_PNG);
+ }
+
+
+Next, png_struct and png_info need to be allocated and initialized. In
+order to ensure that the size of these structures is correct even with a
+dynamically linked libpng, there are functions to initialize and
+allocate the structures. We also pass the library version, optional
+pointers to error handling functions, and a pointer to a data struct for
+use by the error functions, if necessary (the pointer and functions can
+be NULL if the default error handlers are to be used). See the section
+on Changes to Libpng below regarding the old initialization functions.
+The structure allocation functions quietly return NULL if they fail to
+create the structure, so your application should check for that.
+
+ png_structp png_ptr = png_create_read_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+
+ if (!info_ptr)
+ {
+ png_destroy_read_struct(&png_ptr,
+ (png_infopp)NULL, (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ png_infop end_info = png_create_info_struct(png_ptr);
+
+ if (!end_info)
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+If you want to use your own memory allocation routines,
+use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
+png_create_read_struct_2() instead of png_create_read_struct():
+
+ png_structp png_ptr = png_create_read_struct_2
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn, (png_voidp)
+ user_mem_ptr, user_malloc_fn, user_free_fn);
+
+The error handling routines passed to png_create_read_struct()
+and the memory alloc/free routines passed to png_create_struct_2()
+are only necessary if you are not using the libpng supplied error
+handling and memory alloc/free functions.
+
+When libpng encounters an error, it expects to longjmp back
+to your routine. Therefore, you will need to call setjmp and pass
+your png_jmpbuf(png_ptr). If you read the file from different
+routines, you will need to update the jmpbuf field every time you enter
+a new routine that will call a png_*() function.
+
+See your documentation of setjmp/longjmp for your compiler for more
+information on setjmp/longjmp. See the discussion on libpng error
+handling in the Customizing Libpng section below for more information
+on the libpng error handling. If an error occurs, and libpng longjmp's
+back to your setjmp, you will want to call png_destroy_read_struct() to
+free any memory.
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ &end_info);
+ fclose(fp);
+ return (ERROR);
+ }
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the input code. The default for libpng is to
+use the C function fread(). If you use this, you will need to pass a
+valid FILE * in the function png_init_io(). Be sure that the file is
+opened in binary mode. If you wish to handle reading data in another
+way, you need not call the png_init_io() function, but you must then
+implement the libpng I/O methods discussed in the Customizing Libpng
+section below.
+
+ png_init_io(png_ptr, fp);
+
+If you had previously opened the file and read any of the signature from
+the beginning in order to see if this was a PNG file, you need to let
+libpng know that there are some bytes missing from the start of the file.
+
+ png_set_sig_bytes(png_ptr, number);
+
+You can change the zlib compression buffer size to be used while
+reading compressed data with
+
+ png_set_compression_buffer_size(png_ptr, buffer_size);
+
+where the default size is 8192 bytes. Note that the buffer size
+is changed immediately and the buffer is reallocated immediately,
+instead of setting a flag to be acted upon later.
+
+If you want CRC errors to be handled in a different manner than
+the default, use
+
+ png_set_crc_action(png_ptr, crit_action, ancil_action);
+
+The values for png_set_crc_action() say how libpng is to handle CRC errors in
+ancillary and critical chunks, and whether to use the data contained
+therein. Note that it is impossible to "discard" data in a critical
+chunk.
+
+Choices for (int) crit_action are
+ PNG_CRC_DEFAULT 0 error/quit
+ PNG_CRC_ERROR_QUIT 1 error/quit
+ PNG_CRC_WARN_USE 3 warn/use data
+ PNG_CRC_QUIET_USE 4 quiet/use data
+ PNG_CRC_NO_CHANGE 5 use the current value
+
+Choices for (int) ancil_action are
+ PNG_CRC_DEFAULT 0 error/quit
+ PNG_CRC_ERROR_QUIT 1 error/quit
+ PNG_CRC_WARN_DISCARD 2 warn/discard data
+ PNG_CRC_WARN_USE 3 warn/use data
+ PNG_CRC_QUIET_USE 4 quiet/use data
+ PNG_CRC_NO_CHANGE 5 use the current value
+
+.SS Setting up callback code
+
+You can set up a callback function to handle any unknown chunks in the
+input stream. You must supply the function
+
+ read_chunk_callback(png_structp png_ptr,
+ png_unknown_chunkp chunk);
+ {
+ /* The unknown chunk structure contains your
+ chunk data, along with similar data for any other
+ unknown chunks: */
+
+ png_byte name[5];
+ png_byte *data;
+ png_size_t size;
+
+ /* Note that libpng has already taken care of
+ the CRC handling */
+
+ /* put your code here. Search for your chunk in the
+ unknown chunk structure, process it, and return one
+ of the following: */
+
+ return (-n); /* chunk had an error */
+ return (0); /* did not recognize */
+ return (n); /* success */
+ }
+
+(You can give your function another name that you like instead of
+"read_chunk_callback")
+
+To inform libpng about your function, use
+
+ png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
+ read_chunk_callback);
+
+This names not only the callback function, but also a user pointer that
+you can retrieve with
+
+ png_get_user_chunk_ptr(png_ptr);
+
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks will be saved when read, in case your callback function will need
+one or more of them. This behavior can be changed with the
+png_set_keep_unknown_chunks() function, described below.
+
+At this point, you can set up a callback function that will be
+called after each row has been read, which you can use to control
+a progress meter or the like. It's demonstrated in pngtest.c.
+You must supply a function
+
+ void read_row_callback(png_structp png_ptr,
+ png_uint_32 row, int pass);
+ {
+ /* put your code here */
+ }
+
+(You can give it another name that you like instead of "read_row_callback")
+
+To inform libpng about your function, use
+
+ png_set_read_status_fn(png_ptr, read_row_callback);
+
+.SS Unknown-chunk handling
+
+Now you get to set the way the library processes unknown chunks in the
+input PNG stream. Both known and unknown chunks will be read. Normal
+behavior is that known chunks will be parsed into information in
+various info_ptr members while unknown chunks will be discarded. This
+behavior can be wasteful if your application will never use some known
+chunk types. To change this, you can call:
+
+ png_set_keep_unknown_chunks(png_ptr, keep,
+ chunk_list, num_chunks);
+ keep - 0: default unknown chunk handling
+ 1: ignore; do not keep
+ 2: keep only if safe-to-copy
+ 3: keep even if unsafe-to-copy
+
+ You can use these definitions:
+ PNG_HANDLE_CHUNK_AS_DEFAULT 0
+ PNG_HANDLE_CHUNK_NEVER 1
+ PNG_HANDLE_CHUNK_IF_SAFE 2
+ PNG_HANDLE_CHUNK_ALWAYS 3
+
+ chunk_list - list of chunks affected (a byte string,
+ five bytes per chunk, NULL or '\0' if
+ num_chunks is 0)
+
+ num_chunks - number of chunks affected; if 0, all
+ unknown chunks are affected. If nonzero,
+ only the chunks in the list are affected
+
+Unknown chunks declared in this way will be saved as raw data onto a
+list of png_unknown_chunk structures. If a chunk that is normally
+known to libpng is named in the list, it will be handled as unknown,
+according to the "keep" directive. If a chunk is named in successive
+instances of png_set_keep_unknown_chunks(), the final instance will
+take precedence. The IHDR and IEND chunks should not be named in
+chunk_list; if they are, libpng will process them normally anyway.
+
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+ png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'};
+
+ #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+ png_byte unused_chunks[]=
+ {
+ 104, 73, 83, 84, (png_byte) '\0', /* hIST */
+ 105, 84, 88, 116, (png_byte) '\0', /* iTXt */
+ 112, 67, 65, 76, (png_byte) '\0', /* pCAL */
+ 115, 67, 65, 76, (png_byte) '\0', /* sCAL */
+ 115, 80, 76, 84, (png_byte) '\0', /* sPLT */
+ 116, 73, 77, 69, (png_byte) '\0', /* tIME */
+ };
+ #endif
+
+ ...
+
+ #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+ /* ignore all unknown chunks: */
+ png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+
+ /* except for vpAg: */
+ png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+
+ /* also ignore unused known chunks: */
+ png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+ (int)sizeof(unused_chunks)/5);
+ #endif
+
+.SS User limits
+
+The PNG specification allows the width and height of an image to be as
+large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
+Since very few applications really need to process such large images,
+we have imposed an arbitrary 1-million limit on rows and columns.
+Larger images will be rejected immediately with a png_error() call. If
+you wish to override this limit, you can use
+
+ png_set_user_limits(png_ptr, width_max, height_max);
+
+to set your own limits, or use width_max = height_max = 0x7fffffffL
+to allow all valid dimensions (libpng may reject some very large images
+anyway because of potential buffer overflow conditions).
+
+You should put this statement after you create the PNG structure and
+before calling png_read_info(), png_read_png(), or png_process_data().
+If you need to retrieve the limits that are being applied, use
+
+ width_max = png_get_user_width_max(png_ptr);
+ height_max = png_get_user_height_max(png_ptr);
+
+The PNG specification sets no limit on the number of ancillary chunks
+allowed in a PNG datastream. You can impose a limit on the total number
+of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with
+
+ png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
+
+where 0x7fffffffL means unlimited. You can retrieve this limit with
+
+ chunk_cache_max = png_get_chunk_cache_max(png_ptr);
+
+This limit also applies to the number of buffers that can be allocated
+by png_decompress_chunk() while decompressing iTXt, zTXt, and iCCP chunks.
+
+You can also set a limit on the amount of memory that a compressed chunk
+other than IDAT can occupy, with
+
+ png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
+
+and you can retrieve the limit with
+
+ chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
+
+Any chunks that would cause either of these limits to be exceeded will
+be ignored.
+
+.SS The high-level read interface
+
+At this point there are two ways to proceed; through the high-level
+read interface, or through a sequence of low-level read operations.
+You can use the high-level interface if (a) you are willing to read
+the entire image into memory, and (b) the input transformations
+you want to do are limited to the following set:
+
+ PNG_TRANSFORM_IDENTITY No transformation
+ PNG_TRANSFORM_STRIP_16 Strip 16-bit samples to
+ 8 bits
+ PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
+ PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit
+ samples to bytes
+ PNG_TRANSFORM_PACKSWAP Change order of packed
+ pixels to LSB first
+ PNG_TRANSFORM_EXPAND Perform set_expand()
+ PNG_TRANSFORM_INVERT_MONO Invert monochrome images
+ PNG_TRANSFORM_SHIFT Normalize pixels to the
+ sBIT depth
+ PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
+ to BGRA
+ PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
+ to AG
+ PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
+ to transparency
+ PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
+ PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples
+ to RGB (or GA to RGBA)
+
+(This excludes setting a background color, doing gamma transformation,
+quantizing, and setting filler.) If this is the case, simply do this:
+
+ png_read_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some
+set of transformation flags. This call is equivalent to png_read_info(),
+followed the set of transformations indicated by the transform mask,
+then png_read_image(), and finally png_read_end().
+
+(The final parameter of this call is not yet used. Someday it might point
+to transformation parameters required by some future input transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+
+After you have called png_read_png(), you can retrieve the image data
+with
+
+ row_pointers = png_get_rows(png_ptr, info_ptr);
+
+where row_pointers is an array of pointers to the pixel data for each row:
+
+ png_bytep row_pointers[height];
+
+If you know your image size and pixel size ahead of time, you can allocate
+row_pointers prior to calling png_read_png() with
+
+ if (height > PNG_UINT_32_MAX/png_sizeof(png_byte))
+ png_error (png_ptr,
+ "Image is too tall to process in memory");
+
+ if (width > PNG_UINT_32_MAX/pixel_size)
+ png_error (png_ptr,
+ "Image is too wide to process in memory");
+
+ row_pointers = png_malloc(png_ptr,
+ height*png_sizeof(png_bytep));
+
+ for (int i=0; i<height, i++)
+ row_pointers[i]=NULL; /* security precaution */
+
+ for (int i=0; i<height, i++)
+ row_pointers[i]=png_malloc(png_ptr,
+ width*pixel_size);
+
+ png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+Alternatively you could allocate your image in one big block and define
+row_pointers[i] to point into the proper places in your block.
+
+If you use png_set_rows(), the application is responsible for freeing
+row_pointers (and row_pointers[i], if they were separately allocated).
+
+If you don't allocate row_pointers ahead of time, png_read_png() will
+do it, and it'll be free'ed by libpng when you call png_destroy_*().
+
+.SS The low-level read interface
+
+If you are going the low-level route, you are now ready to read all
+the file information up to the actual image data. You do this with a
+call to png_read_info().
+
+ png_read_info(png_ptr, info_ptr);
+
+This will process all chunks up to but not including the image data.
+
+.SS Querying the info structure
+
+Functions are used to get the information from the info_ptr once it
+has been read. Note that these fields may not be completely filled
+in until png_read_end() has read the chunk data following the image.
+
+ png_get_IHDR(png_ptr, info_ptr, &width, &height,
+ &bit_depth, &color_type, &interlace_type,
+ &compression_type, &filter_method);
+
+ width - holds the width of the image
+ in pixels (up to 2^31).
+
+ height - holds the height of the image
+ in pixels (up to 2^31).
+
+ bit_depth - holds the bit depth of one of the
+ image channels. (valid values are
+ 1, 2, 4, 8, 16 and depend also on
+ the color_type. See also
+ significant bits (sBIT) below).
+
+ color_type - describes which color/alpha channels
+ are present.
+ PNG_COLOR_TYPE_GRAY
+ (bit depths 1, 2, 4, 8, 16)
+ PNG_COLOR_TYPE_GRAY_ALPHA
+ (bit depths 8, 16)
+ PNG_COLOR_TYPE_PALETTE
+ (bit depths 1, 2, 4, 8)
+ PNG_COLOR_TYPE_RGB
+ (bit_depths 8, 16)
+ PNG_COLOR_TYPE_RGB_ALPHA
+ (bit_depths 8, 16)
+
+ PNG_COLOR_MASK_PALETTE
+ PNG_COLOR_MASK_COLOR
+ PNG_COLOR_MASK_ALPHA
+
+ interlace_type - (PNG_INTERLACE_NONE or
+ PNG_INTERLACE_ADAM7)
+
+ compression_type - (must be PNG_COMPRESSION_TYPE_BASE
+ for PNG 1.0)
+
+ filter_method - (must be PNG_FILTER_TYPE_BASE
+ for PNG 1.0, and can also be
+ PNG_INTRAPIXEL_DIFFERENCING if
+ the PNG datastream is embedded in
+ a MNG-1.0 datastream)
+
+ Any or all of interlace_type, compression_type, or
+ filter_method can be NULL if you are
+ not interested in their values.
+
+ Note that png_get_IHDR() returns 32-bit data into
+ the application's width and height variables.
+ This is an unsafe situation if these are 16-bit
+ variables. In such situations, the
+ png_get_image_width() and png_get_image_height()
+ functions described below are safer.
+
+ width = png_get_image_width(png_ptr,
+ info_ptr);
+
+ height = png_get_image_height(png_ptr,
+ info_ptr);
+
+ bit_depth = png_get_bit_depth(png_ptr,
+ info_ptr);
+
+ color_type = png_get_color_type(png_ptr,
+ info_ptr);
+
+ interlace_type = png_get_interlace_type(png_ptr,
+ info_ptr);
+
+ compression_type = png_get_compression_type(png_ptr,
+ info_ptr);
+
+ filter_method = png_get_filter_type(png_ptr,
+ info_ptr);
+
+ channels = png_get_channels(png_ptr, info_ptr);
+
+ channels - number of channels of info for the
+ color type (valid values are 1 (GRAY,
+ PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
+ 4 (RGB_ALPHA or RGB + filler byte))
+
+ rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+ rowbytes - number of bytes needed to hold a row
+
+ signature = png_get_signature(png_ptr, info_ptr);
+
+ signature - holds the signature read from the
+ file (if any). The data is kept in
+ the same offset it would be if the
+ whole signature were read (i.e. if an
+ application had already read in 4
+ bytes of signature before starting
+ libpng, the remaining 4 bytes would
+ be in signature[4] through signature[7]
+ (see png_set_sig_bytes())).
+
+These are also important, but their validity depends on whether the chunk
+has been read. The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
+png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
+data has been read, or zero if it is missing. The parameters to the
+png_get_<chunk> are set directly if they are simple data types, or a
+pointer into the info_ptr is returned for any complex types.
+
+ png_get_PLTE(png_ptr, info_ptr, &palette,
+ &num_palette);
+
+ palette - the palette for the file
+ (array of png_color)
+
+ num_palette - number of entries in the palette
+
+ png_get_gAMA(png_ptr, info_ptr, &file_gamma);
+ png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
+
+ file_gamma - the gamma at which the file is
+ written (PNG_INFO_gAMA)
+
+ int_file_gamma - 100,000 times the gamma at which the
+ file is written
+
+ png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
+
+ file_srgb_intent - the rendering intent (PNG_INFO_sRGB)
+ The presence of the sRGB chunk
+ means that the pixel data is in the
+ sRGB color space. This chunk also
+ implies specific values of gAMA and
+ cHRM.
+
+ png_get_iCCP(png_ptr, info_ptr, &name,
+ &compression_type, &profile, &proflen);
+
+ name - The profile name.
+
+ compression_type - The compression type; always
+ PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+ You may give NULL to this argument to
+ ignore it.
+
+ profile - International Color Consortium color
+ profile data. May contain NULs.
+
+ proflen - length of profile data in bytes.
+
+ png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+
+ sig_bit - the number of significant bits for
+ (PNG_INFO_sBIT) each of the gray,
+ red, green, and blue channels,
+ whichever are appropriate for the
+ given color type (png_color_16)
+
+ png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
+ &num_trans, &trans_color);
+
+ trans_alpha - array of alpha (transparency)
+ entries for palette (PNG_INFO_tRNS)
+
+ num_trans - number of transparent entries
+ (PNG_INFO_tRNS)
+
+ trans_color - graylevel or color sample values of
+ the single transparent color for
+ non-paletted images (PNG_INFO_tRNS)
+
+ png_get_hIST(png_ptr, info_ptr, &hist);
+ (PNG_INFO_hIST)
+
+ hist - histogram of palette (array of
+ png_uint_16)
+
+ png_get_tIME(png_ptr, info_ptr, &mod_time);
+
+ mod_time - time image was last modified
+ (PNG_VALID_tIME)
+
+ png_get_bKGD(png_ptr, info_ptr, &background);
+
+ background - background color (PNG_VALID_bKGD)
+ valid 16-bit red, green and blue
+ values, regardless of color_type
+
+ num_comments = png_get_text(png_ptr, info_ptr,
+ &text_ptr, &num_text);
+
+ num_comments - number of comments
+
+ text_ptr - array of png_text holding image
+ comments
+
+ text_ptr[i].compression - type of compression used
+ on "text" PNG_TEXT_COMPRESSION_NONE
+ PNG_TEXT_COMPRESSION_zTXt
+ PNG_ITXT_COMPRESSION_NONE
+ PNG_ITXT_COMPRESSION_zTXt
+
+ text_ptr[i].key - keyword for comment. Must contain
+ 1-79 characters.
+
+ text_ptr[i].text - text comments for current
+ keyword. Can be empty.
+
+ text_ptr[i].text_length - length of text string,
+ after decompression, 0 for iTXt
+
+ text_ptr[i].itxt_length - length of itxt string,
+ after decompression, 0 for tEXt/zTXt
+
+ text_ptr[i].lang - language of comment (empty
+ string for unknown).
+
+ text_ptr[i].lang_key - keyword in UTF-8
+ (empty string for unknown).
+
+ Note that the itxt_length, lang, and lang_key
+ members of the text_ptr structure only exist
+ when the library is built with iTXt chunk support.
+
+ num_text - number of comments (same as
+ num_comments; you can put NULL here
+ to avoid the duplication)
+
+ Note while png_set_text() will accept text, language,
+ and translated keywords that can be NULL pointers, the
+ structure returned by png_get_text will always contain
+ regular zero-terminated C strings. They might be
+ empty strings but they will never be NULL pointers.
+
+ num_spalettes = png_get_sPLT(png_ptr, info_ptr,
+ &palette_ptr);
+
+ num_spalettes - number of sPLT chunks read.
+
+ palette_ptr - array of palette structures holding
+ contents of one or more sPLT chunks
+ read.
+
+ png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
+ &unit_type);
+
+ offset_x - positive offset from the left edge
+ of the screen
+
+ offset_y - positive offset from the top edge
+ of the screen
+
+ unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+ png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
+ &unit_type);
+
+ res_x - pixels/unit physical resolution in
+ x direction
+
+ res_y - pixels/unit physical resolution in
+ x direction
+
+ unit_type - PNG_RESOLUTION_UNKNOWN,
+ PNG_RESOLUTION_METER
+
+ png_get_sCAL(png_ptr, info_ptr, &unit, &width,
+ &height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are doubles)
+
+ png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
+ &height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are strings like "2.54")
+
+ num_unknown_chunks = png_get_unknown_chunks(png_ptr,
+ info_ptr, &unknowns)
+
+ unknowns - array of png_unknown_chunk
+ structures holding unknown chunks
+
+ unknowns[i].name - name of unknown chunk
+
+ unknowns[i].data - data of unknown chunk
+
+ unknowns[i].size - size of unknown chunk's data
+
+ unknowns[i].location - position of chunk in file
+
+ The value of "i" corresponds to the order in which the
+ chunks were read from the PNG file or inserted with the
+ png_set_unknown_chunks() function.
+
+The data from the pHYs chunk can be retrieved in several convenient
+forms:
+
+ res_x = png_get_x_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_y = png_get_y_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_x_and_y = png_get_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_x = png_get_x_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ res_y = png_get_y_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ res_x_and_y = png_get_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
+ info_ptr)
+
+ Each of these returns 0 [signifying "unknown"] if
+ the data is not present or if res_x is 0;
+ res_x_and_y is 0 if res_x != res_y
+
+ Note that because of the way the resolutions are
+ stored internally, the inch conversions won't
+ come out to exactly even number. For example,
+ 72 dpi is stored as 0.28346 pixels/meter, and
+ when this is retrieved it is 71.9988 dpi, so
+ be sure to round the returned value appropriately
+ if you want to display a reasonable-looking result.
+
+The data from the oFFs chunk can be retrieved in several convenient
+forms:
+
+ x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
+
+ y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
+
+ x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
+
+ y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
+
+ Each of these returns 0 [signifying "unknown" if both
+ x and y are 0] if the data is not present or if the
+ chunk is present but the unit is the pixel. The
+ remark about inexact inch conversions applies here
+ as well, because a value in inches can't always be
+ converted to microns and back without some loss
+ of precision.
+
+For more information, see the png_info definition in png.h and the
+PNG specification for chunk contents. Be careful with trusting
+rowbytes, as some of the transformations could increase the space
+needed to hold a row (expand, filler, gray_to_rgb, etc.).
+See png_read_update_info(), below.
+
+A quick word about text_ptr and num_text. PNG stores comments in
+keyword/text pairs, one pair per chunk, with no limit on the number
+of text chunks, and a 2^31 byte limit on their size. While there are
+suggested keywords, there is no requirement to restrict the use to these
+strings. It is strongly suggested that keywords and text be sensible
+to humans (that's the point), so don't use abbreviations. Non-printing
+symbols are not allowed. See the PNG specification for more details.
+There is also no requirement to have text after the keyword.
+
+Keywords should be limited to 79 Latin-1 characters without leading or
+trailing spaces, but non-consecutive spaces are allowed within the
+keyword. It is possible to have the same keyword any number of times.
+The text_ptr is an array of png_text structures, each holding a
+pointer to a language string, a pointer to a keyword and a pointer to
+a text string. The text string, language code, and translated
+keyword may be empty or NULL pointers. The keyword/text
+pairs are put into the array in the order that they are received.
+However, some or all of the text chunks may be after the image, so, to
+make sure you have read all the text chunks, don't mess with these
+until after you read the stuff after the image. This will be
+mentioned again below in the discussion that goes with png_read_end().
+
+.SS Input transformations
+
+After you've read the header information, you can set up the library
+to handle any special transformations of the image data. The various
+ways to transform the data will be described in the order that they
+should occur. This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths. Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data. For example, don't swap red and blue on grayscale data.
+
+The colors used for the background and transparency values should be
+supplied in the same format/depth as the current image data. They
+are stored in the same format/depth as the image data in a bKGD or tRNS
+chunk, so this is what libpng expects for this data. The colors are
+transformed to keep in sync with the image data when an application
+calls the png_read_update_info() routine (see below).
+
+Data will be decoded into the supplied row buffers packed into bytes
+unless the library has been told to transform it into another format.
+For example, 4 bit/pixel paletted or grayscale data will be returned
+2 pixels/byte with the leftmost pixel in the high-order bits of the
+byte, unless png_set_packing() is called. 8-bit RGB data will be stored
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_strip_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert filler bytes, either before or
+after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
+be modified with
+png_set_filler(), png_set_add_alpha(), or png_set_strip_16().
+
+The following code transforms grayscale images of less than 8 to 8 bits,
+changes paletted images to RGB, and adds a full alpha channel if there is
+transparency information in a tRNS chunk. This is most useful on
+grayscale images with bit depths of 2 or 4 or if there is a multiple-image
+viewing application that wishes to treat all images in the same way.
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ png_set_palette_to_rgb(png_ptr);
+
+ if (color_type == PNG_COLOR_TYPE_GRAY &&
+ bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+ if (png_get_valid(png_ptr, info_ptr,
+ PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
+
+These three functions are actually aliases for png_set_expand(), added
+in libpng version 1.0.4, with the function names expanded to improve code
+readability. In some future version they may actually do different
+things.
+
+As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
+added. It expands the sample depth without changing tRNS to alpha.
+
+As of libpng version 1.5.1, not all possible expansions are supported.
+
+In the following table, the 01 means grayscale with depth<8, 31 means
+indexed with depth<8, other numerals represent the color type, "T" means
+the tRNS chunk is present, A means an alpha channel is present, and O
+means tRNS or alpha is present but all pixels in the image are opaque.
+
+ FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O
+ TO
+ 01 -
+ 31 -
+ 0 1 -
+ 0T -
+ 0O -
+ 2 GX -
+ 2T -
+ 2O -
+ 3 1 -
+ 3T -
+ 3O -
+ 4A T -
+ 4O -
+ 6A GX TX TX -
+ 6O GX TX -
+
+Within the matrix,
+ "-" means the transformation is not supported.
+ "X" means the transformation is obtained by png_set_expand().
+ "1" means the transformation is obtained by
+ png_set_expand_gray_1_2_4_to_8
+ "G" means the transformation is obtained by
+ png_set_gray_to_rgb().
+ "P" means the transformation is obtained by
+ png_set_expand_palette_to_rgb().
+ "T" means the transformation is obtained by
+ png_set_tRNS_to_alpha().
+
+PNG can have files with 16 bits per channel. If you only can handle
+8 bits per channel, this will strip the pixels down to 8 bit.
+
+ if (bit_depth == 16)
+ png_set_strip_16(png_ptr);
+
+If, for some reason, you don't need the alpha channel on an image,
+and you want to remove it rather than combining it with the background
+(but the image author certainly had in mind that you *would* combine
+it with the background, so that's what you should probably do):
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ png_set_strip_alpha(png_ptr);
+
+In PNG files, the alpha channel in an image
+is the level of opacity. If you need the alpha channel in an image to
+be the level of transparency instead of opacity, you can invert the
+alpha channel (or the tRNS chunk data) after it's read, so that 0 is
+fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
+images) is fully transparent, with
+
+ png_set_invert_alpha(png_ptr);
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit
+files. This code expands to 1 pixel per byte without changing the
+values of the pixels:
+
+ if (bit_depth < 8)
+ png_set_packing(png_ptr);
+
+PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels
+stored in a PNG image have been "scaled" or "shifted" up to the next
+higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
+to 8 bits/sample in the range [0, 255]). However, it is also possible
+to convert the PNG pixel data back to the original bit depth of the
+image. This call reduces the pixels back down to the original bit depth:
+
+ png_color_8p sig_bit;
+
+ if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+ png_set_shift(png_ptr, sig_bit);
+
+PNG files store 3-color pixels in red, green, blue order. This code
+changes the storage of the pixels to blue, green, red:
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_bgr(png_ptr);
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
+into 4 or 8 bytes for windowing systems that need them in this format:
+
+ if (color_type == PNG_COLOR_TYPE_RGB)
+ png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
+
+where "filler" is the 8 or 16-bit number to fill with, and the location is
+either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
+you want the filler before the RGB or after. This transformation
+does not affect images that already have full alpha channels. To add an
+opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
+will generate RGBA pixels.
+
+Note that png_set_filler() does not change the color type. If you want
+to do that, you can add a true alpha channel with
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_GRAY)
+ png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+This function was added in libpng-1.2.7.
+
+If you are reading an image with an alpha channel, and you need the
+data as ARGB instead of the normal PNG format RGBA:
+
+ if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_swap_alpha(png_ptr);
+
+For some uses, you may want a grayscale image to be represented as
+RGB. This code will do that conversion:
+
+ if (color_type == PNG_COLOR_TYPE_GRAY ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_gray_to_rgb(png_ptr);
+
+Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
+with alpha.
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_rgb_to_gray_fixed(png_ptr, error_action,
+ int red_weight, int green_weight);
+
+ error_action = 1: silently do the conversion
+
+ error_action = 2: issue a warning if the original
+ image has any pixel where
+ red != green or red != blue
+
+ error_action = 3: issue an error and abort the
+ conversion if the original
+ image has any pixel where
+ red != green or red != blue
+
+ red_weight: weight of red component times 100000
+
+ green_weight: weight of green component times 100000
+ If either weight is negative, default
+ weights (21268, 71514) are used.
+
+If you have set error_action = 1 or 2, you can
+later check whether the image really was gray, after processing
+the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
+It will return a png_byte that is zero if the image was gray or
+1 if there were any non-gray pixels. bKGD and sBIT data
+will be silently converted to grayscale, using the green channel
+data, regardless of the error_action setting.
+
+With red_weight+green_weight<=100000,
+the normalized graylevel is computed:
+
+ int rw = red_weight * 65536;
+ int gw = green_weight * 65536;
+ int bw = 65536 - (rw + gw);
+ gray = (rw*red + gw*green + bw*blue)/65536;
+
+The default values approximate those recommended in the Charles
+Poynton's Color FAQ, <http://www.inforamp.net/~poynton/>
+Copyright (c) 1998-01-04 Charles Poynton <poynton at inforamp.net>
+
+ Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+
+Libpng approximates this with integers scaled by 32768:
+
+ Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
+The calculation is done in a linear colorspace, if the image gamma
+can be determined.
+
+If you have a grayscale and you are using png_set_expand_depth(),
+png_set_expand(), or png_set_gray_to_rgb to change to truecolor or to
+a higher bit-depth, you must either supply the background color as a gray
+value at the original file bit-depth (need_expand = 1) or else supply the
+background color as an RGB triplet at the final, expanded bit depth
+(need_expand = 0). Similarly, if you are reading a paletted image, you
+must either supply the background color as a palette index (need_expand = 1)
+or as an RGB triplet that may or may not be in the palette (need_expand = 0).
+
+ png_color_16 my_background;
+ png_color_16p image_background;
+
+ if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+ png_set_background(png_ptr, image_background,
+ PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+ else
+ png_set_background(png_ptr, &my_background,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
+
+The png_set_background() function tells libpng to composite images
+with alpha or simple transparency against the supplied background
+color. If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page). You
+need to tell libpng whether the color is in the gamma space of the
+display (PNG_BACKGROUND_GAMMA_SCREEN for colors you supply), the file
+(PNG_BACKGROUND_GAMMA_FILE for colors from the bKGD chunk), or one
+that is neither of these gammas (PNG_BACKGROUND_GAMMA_UNIQUE - I don't
+know why anyone would use this, but it's here).
+
+To properly display PNG images on any kind of system, the application needs
+to know what the display gamma is. Ideally, the user will know this, and
+the application will allow them to set it. One method of allowing the user
+to set the display gamma separately for each system is to check for a
+SCREEN_GAMMA or DISPLAY_GAMMA environment variable, which will hopefully be
+correctly set.
+
+Note that display_gamma is the overall gamma correction required to produce
+pleasing results, which depends on the lighting conditions in the surrounding
+environment. In a dim or brightly lit room, no compensation other than
+the physical gamma exponent of the monitor is needed, while in a dark room
+a slightly smaller exponent is better.
+
+ double gamma, screen_gamma;
+
+ if (/* We have a user-defined screen
+ gamma value */)
+ {
+ screen_gamma = user_defined_screen_gamma;
+ }
+
+ /* One way that applications can share the same
+ screen gamma value */
+ else if ((gamma_str = getenv("SCREEN_GAMMA"))
+ != NULL)
+ {
+ screen_gamma = (double)atof(gamma_str);
+ }
+
+ /* If we don't have another value */
+ else
+ {
+ screen_gamma = 2.2; /* A good guess for a
+ PC monitor in a bright office or a dim room */
+
+ screen_gamma = 2.0; /* A good guess for a
+ PC monitor in a dark room */
+
+ screen_gamma = 1.7 or 1.0; /* A good
+ guess for Mac systems */
+ }
+
+The functions png_set_gamma() and its fixed point equivalent
+png_set_gamma_fixed() handle gamma transformations of the data.
+Pass both the file gamma and the current screen_gamma. If the file does
+not have a gamma value, you can pass one anyway if you have an idea what
+it is (usually 0.45455 is a good guess for GIF images on PCs). Note
+that file gammas are inverted from screen gammas. See the discussions
+on gamma in the PNG specification for an excellent description of what
+gamma is, and why all applications should support it. It is strongly
+recommended that PNG viewers support gamma correction.
+
+ if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
+ png_set_gamma(png_ptr, screen_gamma, file_gamma);
+
+ else
+ png_set_gamma(png_ptr, screen_gamma, 0.45455);
+
+If you need to reduce an RGB file to a paletted file, or if a paletted
+file has more entries then will fit on your screen, png_set_quantize()
+will do that. Note that this is a simple match quantization that merely
+finds the closest color available. This should work fairly well with
+optimized palettes, but fairly badly with linear color cubes. If you
+pass a palette that is larger then maximum_colors, the file will
+reduce the number of colors in the palette so it will fit into
+maximum_colors. If there is a histogram, it will use it to make
+more intelligent choices when reducing the palette. If there is no
+histogram, it may not do as good a job.
+
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ if (png_get_valid(png_ptr, info_ptr,
+ PNG_INFO_PLTE))
+ {
+ png_uint_16p histogram = NULL;
+
+ png_get_hIST(png_ptr, info_ptr,
+ &histogram);
+ png_set_quantize(png_ptr, palette, num_palette,
+ max_screen_colors, histogram, 1);
+ }
+
+ else
+ {
+ png_color std_color_cube[MAX_SCREEN_COLORS] =
+ { ... colors ... };
+
+ png_set_quantize(png_ptr, std_color_cube,
+ MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
+ NULL,0);
+ }
+ }
+
+PNG files describe monochrome as black being zero and white being one.
+The following code will reverse this (make black be one and white be
+zero):
+
+ if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
+ png_set_invert_mono(png_ptr);
+
+This function can also be used to invert grayscale and gray-alpha images:
+
+ if (color_type == PNG_COLOR_TYPE_GRAY ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_invert_mono(png_ptr);
+
+PNG files store 16 bit pixels in network byte order (big-endian,
+ie. most significant bits first). This code changes the storage to the
+other way (little-endian, i.e. least significant bits first, the
+way PCs store them):
+
+ if (bit_depth == 16)
+ png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+ if (bit_depth < 8)
+ png_set_packswap(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs. This is done by setting a callback
+with
+
+ png_set_read_user_transform_fn(png_ptr,
+ read_transform_fn);
+
+You must supply the function
+
+ void read_transform_fn(png_structp png_ptr, row_info_ptr
+ row_info, png_bytep data)
+
+See pngtest.c for a working example. Your function will be called
+after all of the other transformations have been processed. Take care with
+interlaced images if you do the interlace yourself - the width of the row is the
+width in 'row_info', not the overall image width.
+
+If supported libpng provides two information routines that you can use to find
+where you are in processing the image:
+
+ png_get_current_pass_number(png_structp png_ptr);
+ png_get_current_row_number(png_structp png_ptr);
+
+Don't try using these outside a transform callback - firstly they are only
+supported if user transforms are supported, secondly they may well return
+unexpected results unless the row is actually being processed at the moment they
+are called.
+
+You can also set up a pointer to a user structure for use by your
+callback function, and you can inform libpng that your transform
+function will change the number of channels or bit depth with the
+function
+
+ png_set_user_transform_info(png_ptr, user_ptr,
+ user_depth, user_channels);
+
+The user's application, not libpng, is responsible for allocating and
+freeing any memory required for the user structure.
+
+You can retrieve the pointer via the function
+png_get_user_transform_ptr(). For example:
+
+ voidp read_user_transform_ptr =
+ png_get_user_transform_ptr(png_ptr);
+
+The last thing to handle is interlacing; this is covered in detail below,
+but you must call the function here if you want libpng to handle expansion
+of the interlaced image.
+
+ number_of_passes = png_set_interlace_handling(png_ptr);
+
+After setting the transformations, libpng can update your png_info
+structure to reflect any transformations you've requested with this
+call. This is most useful to update the info structure's rowbytes
+field so you can use it to allocate your image memory. This function
+will also update your palette with the correct screen_gamma and
+background if these have been given with the calls above.
+
+ png_read_update_info(png_ptr, info_ptr);
+
+After you call png_read_update_info(), you can allocate any
+memory you need to hold the image. The row data is simply
+raw byte data for all forms of images. As the actual allocation
+varies among applications, no example will be given. If you
+are allocating one large chunk, you will need to build an
+array of pointers to each row, as it will be needed for some
+of the functions below.
+
+Remember: Before you call png_read_update_info(), the png_get_
+functions return the values corresponding to the original PNG image.
+After you call png_read_update_info the values refer to the image
+that libpng will output. Consequently you must call all the png_set_
+functions before you call png_read_update_info(). This is particularly
+important for png_set_interlace_handling() - if you are going to call
+png_read_update_info() you must call png_set_interlace_handling() before
+it unless you want to receive interlaced output.
+
+.SS Reading image data
+
+After you've allocated memory, you can read the image data.
+The simplest way to do this is in one function call. If you are
+allocating enough memory to hold the whole image, you can just
+call png_read_image() and libpng will read in all the image data
+and put it in the memory area supplied. You will need to pass in
+an array of pointers to each row.
+
+This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() (unless you call
+png_read_update_info()) or call this function multiple times, or any
+of that other stuff necessary with png_read_rows().
+
+ png_read_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+ png_bytep row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to read in the whole image at once, you can
+use png_read_rows() instead. If there is no interlacing (check
+interlace_type == PNG_INTERLACE_NONE), this is simple:
+
+ png_read_rows(png_ptr, row_pointers, NULL,
+ number_of_rows);
+
+where row_pointers is the same as in the png_read_image() call.
+
+If you are doing this just one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+ png_bytep row_pointer = row;
+ png_read_row(png_ptr, row_pointer, NULL);
+
+If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
+get somewhat harder. The only current (PNG Specification version 1.2)
+interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
+a somewhat complicated 2D interlace scheme, known as Adam7, that
+breaks down an image into seven smaller images of varying size, based
+on an 8x8 grid. This number is defined (from libpng 1.5) as
+PNG_INTERLACE_ADAM7_PASSES in png.h
+
+libpng can fill out those images or it can give them to you "as is".
+It is almost always better to have libpng handle the interlacing for you.
+If you want the images filled out, there are two ways to do that. The one
+mentioned in the PNG specification is to expand each pixel to cover
+those pixels that have not been read yet (the "rectangle" method).
+This results in a blocky image for the first pass, which gradually
+smooths out as more pixels are read. The other method is the "sparkle"
+method, where pixels are drawn only in their final locations, with the
+rest of the image remaining whatever colors they were initialized to
+before the start of the read. The first method usually looks better,
+but tends to be slower, as there are more pixels to put in the rows.
+
+If, as is likely, you want libpng to expand the images, call this before
+calling png_start_read_image() or png_read_update_info():
+
+ if (interlace_type == PNG_INTERLACE_ADAM7)
+ number_of_passes
+ = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed. Currently, this is seven,
+but may change if another interlace type is added. This function can be
+called even if the file is not interlaced, where it will return one pass.
+You then need to read the whole image 'number_of_passes' times. Each time
+will distribute the pixels from the current pass to the correct place in
+the output image, so you need to supply the same rows to png_read_rows in
+each pass.
+
+If you are not going to display the image after each pass, but are
+going to wait until the entire image is read in, use the sparkle
+effect. This effect is faster and the end result of either method
+is exactly the same. If you are planning on displaying the image
+after each pass, the "rectangle" effect is generally considered the
+better looking one.
+
+If you only want the "sparkle" effect, just call png_read_rows() as
+normal, with the third parameter NULL. Make sure you make pass over
+the image number_of_passes times, and you don't change the data in the
+rows between calls. You can change the locations of the data, just
+not the data. Each pass only writes the pixels appropriate for that
+pass, and assumes the data from previous passes is still valid.
+
+ png_read_rows(png_ptr, row_pointers, NULL,
+ number_of_rows);
+
+If you only want the first effect (the rectangles), do the same as
+before except pass the row buffer in the third parameter, and leave
+the second parameter NULL.
+
+ png_read_rows(png_ptr, NULL, row_pointers,
+ number_of_rows);
+
+If you don't want libpng to handle the interlacing details, just call
+png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
+Each of the images is a valid image by itself, however you will almost
+certainly need to distribute the pixels from each sub-image to the
+correct place. This is where everything gets very tricky.
+
+If you want to retrieve the separate images you must pass the correct
+number of rows to each successive call of png_read_rows(). The calculation
+gets pretty complicated for small images, where some sub-images may
+not even exist because either their width or height ends up zero.
+libpng provides two macros to help you in 1.5 and later versions:
+
+ png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
+ png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
+
+Respectively these tell you the width and height of the sub-image
+corresponding to the numbered pass. 'pass' is in in the range 0 to 6 -
+this can be confusing because the specification refers to the same passes
+as 1 to 7! Be careful, you must check both the width and height before
+calling png_read_rows() and not call it for that pass if either is zero.
+
+You can, of course, read each sub-image row by row. If you want to
+produce optimal code to make a pixel-by-pixel transformation of an
+interlaced image this is the best approach; read each row of each pass,
+transform it, and write it out to a new interlaced image.
+
+If you want to de-interlace the image yourself libpng provides further
+macros to help that tell you where to place the pixels in the output image.
+Because the interlacing scheme is rectangular - sub-image pixels are always
+arranged on a rectangular grid - all you need to know for each pass is the
+starting column and row in the output image of the first pixel plus the
+spacing between each pixel. As of libpng 1.5 there are four macros to
+retrieve this information:
+
+ png_uint_32 x = PNG_PASS_START_COL(pass);
+ png_uint_32 y = PNG_PASS_START_ROW(pass);
+ png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
+ png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
+
+These allow you to write the obvious loop:
+
+ png_uint_32 input_y = 0;
+ png_uint_32 output_y = PNG_PASS_START_ROW(pass);
+
+ while (output_y < output_image_height)
+ {
+ png_uint_32 input_x = 0;
+ png_uint_32 output_x = PNG_PASS_START_COL(pass);
+
+ while (output_x < output_image_width)
+ {
+ image[output_y][output_x] =
+ subimage[pass][input_y][input_x++];
+
+ output_x += xStep;
+ }
+
+ ++input_y;
+ output_y += yStep;
+ }
+
+Notice that the steps between successive output rows and columns are
+returned as shifts. This is possible because the pixels in the subimages
+are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
+image. In practice you may need to directly calculate the output coordinate
+given an input coordinate. libpng provides two further macros for this
+purpose:
+
+ png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
+ png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
+
+Finally a pair of macros are provided to tell you if a particular image
+row or column appears in a given pass:
+
+ int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
+ int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
+
+Bear in mind that you will probably also need to check the width and height
+of the pass in addition to the above to be sure the pass even exists!
+
+With any luck you are convinced by now that you don't want to do your own
+interlace handling. In reality normally the only good reason for doing this
+is if you are processing PNG files on a pixel-by-pixel basis and don't want
+to load the whole file into memory when it is interlaced.
+
+libpng includes a test program, pngvalid, that illustrates reading and
+writing of interlaced images. If you can't get interlacing to work in your
+code and don't want to leave it to libpng (the recommended approach) see
+how pngvalid.c does it.
+
+.SS Finishing a sequential read
+
+After you are finished reading the image through the
+low-level interface, you can finish reading the file. If you are
+interested in comments or time, which may be stored either before or
+after the image data, you should pass the separate png_info struct if
+you want to keep the comments from before and after the image
+separate. If you are not interested, you can pass NULL.
+
+ png_read_end(png_ptr, end_info);
+
+When you are done, you can free all memory allocated by libpng like this:
+
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ &end_info);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+ png_free_data(png_ptr, info_ptr, mask, seq)
+
+ mask - identifies data to be freed, a mask
+ containing the bitwise OR of one or
+ more of
+ PNG_FREE_PLTE, PNG_FREE_TRNS,
+ PNG_FREE_HIST, PNG_FREE_ICCP,
+ PNG_FREE_PCAL, PNG_FREE_ROWS,
+ PNG_FREE_SCAL, PNG_FREE_SPLT,
+ PNG_FREE_TEXT, PNG_FREE_UNKN,
+ or simply PNG_FREE_ALL
+
+ seq - sequence number of item to be freed
+ (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng, and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+The default behavior is only to free data that was allocated internally
+by libpng. This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_zalloc() and passed in via a png_set_*() function, with
+
+ png_data_freer(png_ptr, info_ptr, freer, mask)
+
+ freer - one of
+ PNG_DESTROY_WILL_FREE_DATA
+ PNG_SET_WILL_FREE_DATA
+ PNG_USER_WILL_FREE_DATA
+
+ mask - which data elements are affected
+ same choices as in png_free_data()
+
+This function only affects data that has already been allocated.
+You can call this function after reading the PNG data but before calling
+any png_set_*() functions, to control whether the user or the png_set_*()
+function is responsible for freeing any existing data that might be present,
+and again after the png_set_*() functions to control whether the user
+or png_destroy_*() is supposed to free the data. When the user assumes
+responsibility for libpng-allocated data, the application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_zalloc() to allocate it.
+
+If you allocated your row_pointers in a single block, as suggested above in
+the description of the high level read interface, you must not transfer
+responsibility for freeing it to the png_set_rows or png_read_destroy function,
+because they would also try to free the individual row_pointers[i].
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key. Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+
+The png_free_data() function will turn off the "valid" flag for anything
+it frees. If you need to turn the flag off for a chunk that was freed by
+your application instead of by libpng, you can use
+
+ png_set_invalid(png_ptr, info_ptr, mask);
+
+ mask - identifies the chunks to be made invalid,
+ containing the bitwise OR of one or
+ more of
+ PNG_INFO_gAMA, PNG_INFO_sBIT,
+ PNG_INFO_cHRM, PNG_INFO_PLTE,
+ PNG_INFO_tRNS, PNG_INFO_bKGD,
+ PNG_INFO_hIST, PNG_INFO_pHYs,
+ PNG_INFO_oFFs, PNG_INFO_tIME,
+ PNG_INFO_pCAL, PNG_INFO_sRGB,
+ PNG_INFO_iCCP, PNG_INFO_sPLT,
+ PNG_INFO_sCAL, PNG_INFO_IDAT
+
+For a more compact example of reading a PNG image, see the file example.c.
+
+.SS Reading PNG files progressively
+
+The progressive reader is slightly different then the non-progressive
+reader. Instead of calling png_read_info(), png_read_rows(), and
+png_read_end(), you make one call to png_process_data(), which calls
+callbacks when it has the info, a row, or the end of the image. You
+set up these callbacks with png_set_progressive_read_fn(). You don't
+have to worry about the input/output functions of libpng, as you are
+giving the library the data directly in png_process_data(). I will
+assume that you have read the section on reading PNG files above,
+so I will only highlight the differences (although I will show
+all of the code).
+
+png_structp png_ptr;
+png_infop info_ptr;
+
+ /* An example code fragment of how you would
+ initialize the progressive reader in your
+ application. */
+ int
+ initialize_png_reader()
+ {
+ png_ptr = png_create_read_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ info_ptr = png_create_info_struct(png_ptr);
+
+ if (!info_ptr)
+ {
+ png_destroy_read_struct(&png_ptr,
+ (png_infopp)NULL, (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ /* This one's new. You can provide functions
+ to be called when the header info is valid,
+ when each row is completed, and when the image
+ is finished. If you aren't using all functions,
+ you can specify NULL parameters. Even when all
+ three functions are NULL, you need to call
+ png_set_progressive_read_fn(). You can use
+ any struct as the user_ptr (cast to a void pointer
+ for the function call), and retrieve the pointer
+ from inside the callbacks using the function
+
+ png_get_progressive_ptr(png_ptr);
+
+ which will return a void pointer, which you have
+ to cast appropriately.
+ */
+ png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
+ info_callback, row_callback, end_callback);
+
+ return 0;
+ }
+
+ /* A code fragment that you call as you receive blocks
+ of data */
+ int
+ process_data(png_bytep buffer, png_uint_32 length)
+ {
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ /* This one's new also. Simply give it a chunk
+ of data from the file stream (in order, of
+ course). On machines with segmented memory
+ models machines, don't give it any more than
+ 64K. The library seems to run fine with sizes
+ of 4K. Although you can give it much less if
+ necessary (I assume you can give it chunks of
+ 1 byte, I haven't tried less then 256 bytes
+ yet). When this function returns, you may
+ want to display any rows that were generated
+ in the row callback if you don't already do
+ so there.
+ */
+ png_process_data(png_ptr, info_ptr, buffer, length);
+
+ /* At this point you can call png_process_data_skip if
+ you want to handle data the library will skip yourself;
+ it simply returns the number of bytes to skip (and stops
+ libpng skipping that number of bytes on the next
+ png_process_data call).
+ return 0;
+ }
+
+ /* This function is called (as set by
+ png_set_progressive_read_fn() above) when enough data
+ has been supplied so all of the header has been
+ read.
+ */
+ void
+ info_callback(png_structp png_ptr, png_infop info)
+ {
+ /* Do any setup here, including setting any of
+ the transformations mentioned in the Reading
+ PNG files section. For now, you _must_ call
+ either png_start_read_image() or
+ png_read_update_info() after all the
+ transformations are set (even if you don't set
+ any). You may start getting rows before
+ png_process_data() returns, so this is your
+ last chance to prepare for that.
+
+ This is where you turn on interlace handling,
+ assuming you don't want to do it yourself.
+
+ If you need to you can stop the processing of
+ your original input data at this point by calling
+ png_process_data_pause. This returns the number
+ of unprocessed bytes from the last png_process_data
+ call - it is up to you to ensure that the next call
+ sees these bytes again. If you don't want to bother
+ with this you can get libpng to cache the unread
+ bytes by setting the 'save' parameter (see png.h) but
+ then libpng will have to copy the data internally.
+ */
+ }
+
+ /* This function is called when each row of image
+ data is complete */
+ void
+ row_callback(png_structp png_ptr, png_bytep new_row,
+ png_uint_32 row_num, int pass)
+ {
+ /* If the image is interlaced, and you turned
+ on the interlace handler, this function will
+ be called for every row in every pass. Some
+ of these rows will not be changed from the
+ previous pass. When the row is not changed,
+ the new_row variable will be NULL. The rows
+ and passes are called in order, so you don't
+ really need the row_num and pass, but I'm
+ supplying them because it may make your life
+ easier.
+
+ If you did not turn on interlace handling then
+ the callback is called for each row of each
+ sub-image when the image is interlaced. In this
+ case 'row_num' is the row in the sub-image, not
+ the row in the output image as it is in all other
+ cases.
+
+ For the non-NULL rows of interlaced images when
+ you have switched on libpng interlace handling,
+ you must call png_progressive_combine_row()
+ passing in the row and the old row. You can
+ call this function for NULL rows (it will just
+ return) and for non-interlaced images (it just
+ does the memcpy for you) if it will make the
+ code easier. Thus, you can just do this for
+ all cases if you switch on interlace handling;
+ */
+
+ png_progressive_combine_row(png_ptr, old_row,
+ new_row);
+
+ /* where old_row is what was displayed for
+ previously for the row. Note that the first
+ pass (pass == 0, really) will completely cover
+ the old row, so the rows do not have to be
+ initialized. After the first pass (and only
+ for interlaced images), you will have to pass
+ the current row, and the function will combine
+ the old row and the new row.
+
+ You can also call png_process_data_pause in this
+ callback - see above.
+ */
+ }
+
+ void
+ end_callback(png_structp png_ptr, png_infop info)
+ {
+ /* This function is called after the whole image
+ has been read, including any chunks after the
+ image (up to and including the IEND). You
+ will usually have the same info chunk as you
+ had in the header, although some data may have
+ been added to the comments and time fields.
+
+ Most people won't do much here, perhaps setting
+ a flag that marks the image as finished.
+ */
+ }
+
+
+
+.SH IV. Writing
+
+Much of this is very similar to reading. However, everything of
+importance is repeated here, so you won't have to constantly look
+back up in the reading section to understand writing.
+
+.SS Setup
+
+You will want to do the I/O initialization before you get into libpng,
+so if it doesn't work, you don't have anything to undo. If you are not
+using the standard I/O functions, you will need to replace them with
+custom writing functions. See the discussion under Customizing libpng.
+
+ FILE *fp = fopen(file_name, "wb");
+
+ if (!fp)
+ return (ERROR);
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these can be both relatively large, you may not want to store these
+on the stack, unless you have stack space to spare. Of course, you
+will want to check if they return NULL. If you are also reading,
+you won't want to name your read structure and your write structure
+both "png_ptr"; you can call them anything you like, such as
+"read_ptr" and "write_ptr". Look at pngtest.c, for example.
+
+ png_structp png_ptr = png_create_write_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+ if (!info_ptr)
+ {
+ png_destroy_write_struct(&png_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+If you want to use your own memory allocation routines,
+define PNG_USER_MEM_SUPPORTED and use
+png_create_write_struct_2() instead of png_create_write_struct():
+
+ png_structp png_ptr = png_create_write_struct_2
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn, (png_voidp)
+ user_mem_ptr, user_malloc_fn, user_free_fn);
+
+After you have these structures, you will need to set up the
+error handling. When libpng encounters an error, it expects to
+longjmp() back to your routine. Therefore, you will need to call
+setjmp() and pass the png_jmpbuf(png_ptr). If you
+write the file from different routines, you will need to update
+the png_jmpbuf(png_ptr) every time you enter a new routine that will
+call a png_*() function. See your documentation of setjmp/longjmp
+for your compiler for more information on setjmp/longjmp. See
+the discussion on libpng error handling in the Customizing Libpng
+section below for more information on the libpng error handling.
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ fclose(fp);
+ return (ERROR);
+ }
+ ...
+ return;
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the output code. The default for libpng is to
+use the C function fwrite(). If you use this, you will need to pass a
+valid FILE * in the function png_init_io(). Be sure that the file is
+opened in binary mode. Again, if you wish to handle writing data in
+another way, see the discussion on libpng I/O handling in the Customizing
+Libpng section below.
+
+ png_init_io(png_ptr, fp);
+
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+ png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
+.SS Write callbacks
+
+At this point, you can set up a callback function that will be
+called after each row has been written, which you can use to control
+a progress meter or the like. It's demonstrated in pngtest.c.
+You must supply a function
+
+ void write_row_callback(png_structp png_ptr, png_uint_32 row,
+ int pass);
+ {
+ /* put your code here */
+ }
+
+(You can give it another name that you like instead of "write_row_callback")
+
+To inform libpng about your function, use
+
+ png_set_write_status_fn(png_ptr, write_row_callback);
+
+You now have the option of modifying how the compression library will
+run. The following functions are mainly for testing, but may be useful
+in some cases, like if you need to write PNG files extremely fast and
+are willing to give up some compression, or if you want to get the
+maximum possible compression at the expense of slower writing. If you
+have no special needs in this area, let the library do what it wants by
+not calling this function at all, as it has been tuned to deliver a good
+speed/compression ratio. The second parameter to png_set_filter() is
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream). The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline. See the PNG specification for details on the specific
+filter types.
+
+
+ /* turn on or off filtering, and/or choose
+ specific filters. You can use either a single
+ PNG_FILTER_VALUE_NAME or the bitwise OR of one
+ or more PNG_FILTER_NAME masks.
+ */
+ png_set_filter(png_ptr, 0,
+ PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE |
+ PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB |
+ PNG_FILTER_UP | PNG_FILTER_VALUE_UP |
+ PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG |
+ PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
+ PNG_ALL_FILTERS);
+
+If an application wants to start and stop using particular filters during
+compression, it should start out with all of the filters (to ensure that
+the previous row of pixels will be stored in case it's needed later),
+and then add and remove them after the start of compression.
+
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
+The png_set_compression_*() functions interface to the zlib compression
+library, and should mostly be ignored unless you really know what you are
+doing. The only generally useful call is png_set_compression_level()
+which changes how much time zlib spends on trying to compress the image
+data. See the Compression Library (zlib.h and algorithm.txt, distributed
+with zlib) for details on the compression levels.
+
+ /* set the zlib compression level */
+ png_set_compression_level(png_ptr,
+ Z_BEST_COMPRESSION);
+
+ /* set other zlib parameters */
+ png_set_compression_mem_level(png_ptr, 8);
+ png_set_compression_strategy(png_ptr,
+ Z_DEFAULT_STRATEGY);
+ png_set_compression_window_bits(png_ptr, 15);
+ png_set_compression_method(png_ptr, 8);
+ png_set_compression_buffer_size(png_ptr, 8192)
+
+extern PNG_EXPORT(void,png_set_zbuf_size)
+
+.SS Setting the contents of info for output
+
+You now need to fill in the png_info structure with all the data you
+wish to write before the actual image. Note that the only thing you
+are allowed to write after the image is the text chunks and the time
+chunk (as of PNG Specification 1.2, anyway). See png_write_end() and
+the latest PNG specification for more information on that. If you
+wish to write them before the image, fill them in now, and flag that
+data as being valid. If you want to wait until after the data, don't
+fill them until png_write_end(). For all the fields in png_info and
+their data types, see png.h. For explanations of what the fields
+contain, see the PNG specification.
+
+Some of the more important parts of the png_info are:
+
+ png_set_IHDR(png_ptr, info_ptr, width, height,
+ bit_depth, color_type, interlace_type,
+ compression_type, filter_method)
+
+ width - holds the width of the image
+ in pixels (up to 2^31).
+
+ height - holds the height of the image
+ in pixels (up to 2^31).
+
+ bit_depth - holds the bit depth of one of the
+ image channels.
+ (valid values are 1, 2, 4, 8, 16
+ and depend also on the
+ color_type. See also significant
+ bits (sBIT) below).
+
+ color_type - describes which color/alpha
+ channels are present.
+ PNG_COLOR_TYPE_GRAY
+ (bit depths 1, 2, 4, 8, 16)
+ PNG_COLOR_TYPE_GRAY_ALPHA
+ (bit depths 8, 16)
+ PNG_COLOR_TYPE_PALETTE
+ (bit depths 1, 2, 4, 8)
+ PNG_COLOR_TYPE_RGB
+ (bit_depths 8, 16)
+ PNG_COLOR_TYPE_RGB_ALPHA
+ (bit_depths 8, 16)
+
+ PNG_COLOR_MASK_PALETTE
+ PNG_COLOR_MASK_COLOR
+ PNG_COLOR_MASK_ALPHA
+
+ interlace_type - PNG_INTERLACE_NONE or
+ PNG_INTERLACE_ADAM7
+
+ compression_type - (must be
+ PNG_COMPRESSION_TYPE_DEFAULT)
+
+ filter_method - (must be PNG_FILTER_TYPE_DEFAULT
+ or, if you are writing a PNG to
+ be embedded in a MNG datastream,
+ can also be
+ PNG_INTRAPIXEL_DIFFERENCING)
+
+If you call png_set_IHDR(), the call must appear before any of the
+other png_set_*() functions, because they might require access to some of
+the IHDR settings. The remaining png_set_*() functions can be called
+in any order.
+
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
+
+ png_set_PLTE(png_ptr, info_ptr, palette,
+ num_palette);
+
+ palette - the palette for the file
+ (array of png_color)
+ num_palette - number of entries in the palette
+
+ png_set_gAMA(png_ptr, info_ptr, file_gamma);
+ png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+
+ file_gamma - the gamma at which the image was
+ created (PNG_INFO_gAMA)
+
+ int_file_gamma - 100,000 times the gamma at which
+ the image was created
+
+ png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+ srgb_intent - the rendering intent
+ (PNG_INFO_sRGB) The presence of
+ the sRGB chunk means that the pixel
+ data is in the sRGB color space.
+ This chunk also implies specific
+ values of gAMA and cHRM. Rendering
+ intent is the CSS-1 property that
+ has been defined by the International
+ Color Consortium
+ (http://www.color.org).
+ It can be one of
+ PNG_sRGB_INTENT_SATURATION,
+ PNG_sRGB_INTENT_PERCEPTUAL,
+ PNG_sRGB_INTENT_ABSOLUTE, or
+ PNG_sRGB_INTENT_RELATIVE.
+
+
+ png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
+ srgb_intent);
+
+ srgb_intent - the rendering intent
+ (PNG_INFO_sRGB) The presence of the
+ sRGB chunk means that the pixel
+ data is in the sRGB color space.
+ This function also causes gAMA and
+ cHRM chunks with the specific values
+ that are consistent with sRGB to be
+ written.
+
+ png_set_iCCP(png_ptr, info_ptr, name, compression_type,
+ profile, proflen);
+
+ name - The profile name.
+
+ compression_type - The compression type; always
+ PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+ You may give NULL to this argument to
+ ignore it.
+
+ profile - International Color Consortium color
+ profile data. May contain NULs.
+
+ proflen - length of profile data in bytes.
+
+ png_set_sBIT(png_ptr, info_ptr, sig_bit);
+
+ sig_bit - the number of significant bits for
+ (PNG_INFO_sBIT) each of the gray, red,
+ green, and blue channels, whichever are
+ appropriate for the given color type
+ (png_color_16)
+
+ png_set_tRNS(png_ptr, info_ptr, trans_alpha,
+ num_trans, trans_color);
+
+ trans_alpha - array of alpha (transparency)
+ entries for palette (PNG_INFO_tRNS)
+
+ trans_color - graylevel or color sample values
+ (in order red, green, blue) of the
+ single transparent color for
+ non-paletted images (PNG_INFO_tRNS)
+
+ num_trans - number of transparent entries
+ (PNG_INFO_tRNS)
+
+ png_set_hIST(png_ptr, info_ptr, hist);
+
+ hist - histogram of palette (array of
+ png_uint_16) (PNG_INFO_hIST)
+
+ png_set_tIME(png_ptr, info_ptr, mod_time);
+
+ mod_time - time image was last modified
+ (PNG_VALID_tIME)
+
+ png_set_bKGD(png_ptr, info_ptr, background);
+
+ background - background color (PNG_VALID_bKGD)
+
+ png_set_text(png_ptr, info_ptr, text_ptr, num_text);
+
+ text_ptr - array of png_text holding image
+ comments
+
+ text_ptr[i].compression - type of compression used
+ on "text" PNG_TEXT_COMPRESSION_NONE
+ PNG_TEXT_COMPRESSION_zTXt
+ PNG_ITXT_COMPRESSION_NONE
+ PNG_ITXT_COMPRESSION_zTXt
+ text_ptr[i].key - keyword for comment. Must contain
+ 1-79 characters.
+ text_ptr[i].text - text comments for current
+ keyword. Can be NULL or empty.
+ text_ptr[i].text_length - length of text string,
+ after decompression, 0 for iTXt
+ text_ptr[i].itxt_length - length of itxt string,
+ after decompression, 0 for tEXt/zTXt
+ text_ptr[i].lang - language of comment (NULL or
+ empty for unknown).
+ text_ptr[i].translated_keyword - keyword in UTF-8 (NULL
+ or empty for unknown).
+ Note that the itxt_length, lang, and lang_key
+ members of the text_ptr structure only exist
+ when the library is built with iTXt chunk support.
+
+ num_text - number of comments
+
+ png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
+ num_spalettes);
+
+ palette_ptr - array of png_sPLT_struct structures
+ to be added to the list of palettes
+ in the info structure.
+ num_spalettes - number of palette structures to be
+ added.
+
+ png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
+ unit_type);
+
+ offset_x - positive offset from the left
+ edge of the screen
+
+ offset_y - positive offset from the top
+ edge of the screen
+
+ unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+ png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
+ unit_type);
+
+ res_x - pixels/unit physical resolution
+ in x direction
+
+ res_y - pixels/unit physical resolution
+ in y direction
+
+ unit_type - PNG_RESOLUTION_UNKNOWN,
+ PNG_RESOLUTION_METER
+
+ png_set_sCAL(png_ptr, info_ptr, unit, width, height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are doubles)
+
+ png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are strings like "2.54")
+
+ png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
+ num_unknowns)
+
+ unknowns - array of png_unknown_chunk
+ structures holding unknown chunks
+ unknowns[i].name - name of unknown chunk
+ unknowns[i].data - data of unknown chunk
+ unknowns[i].size - size of unknown chunk's data
+ unknowns[i].location - position to write chunk in file
+ 0: do not write chunk
+ PNG_HAVE_IHDR: before PLTE
+ PNG_HAVE_PLTE: before IDAT
+ PNG_AFTER_IDAT: after IDAT
+
+The "location" member is set automatically according to
+what part of the output file has already been written.
+You can change its value after calling png_set_unknown_chunks()
+as demonstrated in pngtest.c. Within each of the "locations",
+the chunks are sequenced according to their position in the
+structure (that is, the value of "i", which is the order in which
+the chunk was either read from the input file or defined with
+png_set_unknown_chunks).
+
+A quick word about text and num_text. text is an array of png_text
+structures. num_text is the number of valid structures in the array.
+Each png_text structure holds a language code, a keyword, a text value,
+and a compression type.
+
+The compression types have the same valid numbers as the compression
+types of the image data. Currently, the only valid number is zero.
+However, you can store text either compressed or uncompressed, unlike
+images, which always have to be compressed. So if you don't want the
+text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
+Because tEXt and zTXt chunks don't have a language field, if you
+specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
+any language code or translated keyword will not be written out.
+
+Until text gets around 1000 bytes, it is not worth compressing it.
+After the text has been written out to the file, the compression type
+is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
+so that it isn't written out again at the end (in case you are calling
+png_write_end() with the same struct).
+
+The keywords that are given in the PNG Specification are:
+
+ Title Short (one line) title or
+ caption for image
+
+ Author Name of image's creator
+
+ Description Description of image (possibly long)
+
+ Copyright Copyright notice
+
+ Creation Time Time of original image creation
+ (usually RFC 1123 format, see below)
+
+ Software Software used to create the image
+
+ Disclaimer Legal disclaimer
+
+ Warning Warning of nature of content
+
+ Source Device used to create the image
+
+ Comment Miscellaneous comment; conversion
+ from other image format
+
+The keyword-text pairs work like this. Keywords should be short
+simple descriptions of what the comment is about. Some typical
+keywords are found in the PNG specification, as is some recommendations
+on keywords. You can repeat keywords in a file. You can even write
+some text before the image and some after. For example, you may want
+to put a description of the image before the image, but leave the
+disclaimer until after, so viewers working over modem connections
+don't have to wait for the disclaimer to go over the modem before
+they start seeing the image. Finally, keywords should be full
+words, not abbreviations. Keywords and text are in the ISO 8859-1
+(Latin-1) character set (a superset of regular ASCII) and can not
+contain NUL characters, and should not contain control or other
+unprintable characters. To make the comments widely readable, stick
+with basic ASCII, and avoid machine specific character set extensions
+like the IBM-PC character set. The keyword must be present, but
+you can leave off the text string on non-compressed pairs.
+Compressed pairs must have a text string, as only the text string
+is compressed anyway, so the compression would be meaningless.
+
+PNG supports modification time via the png_time structure. Two
+conversion routines are provided, png_convert_from_time_t() for
+time_t and png_convert_from_struct_tm() for struct tm. The
+time_t routine uses gmtime(). You don't have to use either of
+these, but if you wish to fill in the png_time structure directly,
+you should provide the time in universal time (GMT) if possible
+instead of your local time. Note that the year number is the full
+year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
+that months start with 1.
+
+If you want to store the time of the original image creation, you should
+use a plain tEXt chunk with the "Creation Time" keyword. This is
+necessary because the "creation time" of a PNG image is somewhat vague,
+depending on whether you mean the PNG file, the time the image was
+created in a non-PNG format, a still photo from which the image was
+scanned, or possibly the subject matter itself. In order to facilitate
+machine-readable dates, it is recommended that the "Creation Time"
+tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
+although this isn't a requirement. Unlike the tIME chunk, the
+"Creation Time" tEXt chunk is not expected to be automatically changed
+by the software. To facilitate the use of RFC 1123 dates, a function
+png_convert_to_rfc1123(png_timep) is provided to convert from PNG
+time to an RFC 1123 format string.
+
+.SS Writing unknown chunks
+
+You can use the png_set_unknown_chunks function to queue up chunks
+for writing. You give it a chunk name, raw data, and a size; that's
+all there is to it. The chunks will be written by the next following
+png_write_info_before_PLTE, png_write_info, or png_write_end function.
+Any chunks previously read into the info structure's unknown-chunk
+list will also be written out in a sequence that satisfies the PNG
+specification's ordering rules.
+
+.SS The high-level write interface
+
+At this point there are two ways to proceed; through the high-level
+write interface, or through a sequence of low-level write operations.
+You can use the high-level interface if your image data is present
+in the info structure. All defined output
+transformations are permitted, enabled by the following masks.
+
+ PNG_TRANSFORM_IDENTITY No transformation
+ PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples
+ PNG_TRANSFORM_PACKSWAP Change order of packed
+ pixels to LSB first
+ PNG_TRANSFORM_INVERT_MONO Invert monochrome images
+ PNG_TRANSFORM_SHIFT Normalize pixels to the
+ sBIT depth
+ PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
+ to BGRA
+ PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
+ to AG
+ PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
+ to transparency
+ PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
+ PNG_TRANSFORM_STRIP_FILLER Strip out filler
+ bytes (deprecated).
+ PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
+ filler bytes
+ PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing
+ filler bytes
+
+If you have valid image data in the info structure (you can use
+png_set_rows() to put image data in the info structure), simply do this:
+
+ png_write_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some set of
+transformation flags. This call is equivalent to png_write_info(),
+followed the set of transformations indicated by the transform mask,
+then png_write_image(), and finally png_write_end().
+
+(The final parameter of this call is not yet used. Someday it might point
+to transformation parameters required by some future output transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+
+.SS The low-level write interface
+
+If you are going the low-level route instead, you are now ready to
+write all the file information up to the actual image data. You do
+this with a call to png_write_info().
+
+ png_write_info(png_ptr, info_ptr);
+
+Note that there is one transformation you may need to do before
+png_write_info(). In PNG files, the alpha channel in an image is the
+level of opacity. If your data is supplied as a level of transparency,
+you can invert the alpha channel before you write it, so that 0 is
+fully transparent and 255 (in 8-bit or paletted images) or 65535
+(in 16-bit images) is fully opaque, with
+
+ png_set_invert_alpha(png_ptr);
+
+This must appear before png_write_info() instead of later with the
+other transformations because in the case of paletted images the tRNS
+chunk data has to be inverted before the tRNS chunk is written. If
+your image is not a paletted image, the tRNS data (which in such cases
+represents a single color to be rendered as transparent) won't need to
+be changed, and you can safely do this transformation after your
+png_write_info() call.
+
+If you need to write a private chunk that you want to appear before
+the PLTE chunk when PLTE is present, you can write the PNG info in
+two steps, and insert code to write your own chunk between them:
+
+ png_write_info_before_PLTE(png_ptr, info_ptr);
+ png_set_unknown_chunks(png_ptr, info_ptr, ...);
+ png_write_info(png_ptr, info_ptr);
+
+After you've written the file information, you can set up the library
+to handle any special transformations of the image data. The various
+ways to transform the data will be described in the order that they
+should occur. This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths. Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data. For example, don't swap red and blue on grayscale data.
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code tells
+the library to strip input data that has 4 or 8 bytes per pixel down
+to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
+bytes per pixel).
+
+ png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
+PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
+is stored XRGB or RGBX.
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit files.
+If the data is supplied at 1 pixel per byte, use this code, which will
+correctly pack the pixels into a single byte:
+
+ png_set_packing(png_ptr);
+
+PNG files reduce possible bit depths to 1, 2, 4, 8, and 16. If your
+data is of another bit depth, you can write an sBIT chunk into the
+file so that decoders can recover the original data if desired.
+
+ /* Set the true bit depth of the image data */
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ sig_bit.red = true_bit_depth;
+ sig_bit.green = true_bit_depth;
+ sig_bit.blue = true_bit_depth;
+ }
+
+ else
+ {
+ sig_bit.gray = true_bit_depth;
+ }
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ sig_bit.alpha = true_bit_depth;
+ }
+
+ png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+If the data is stored in the row buffer in a bit depth other than
+one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
+this will scale the values to appear to be the correct bit depth as
+is required by PNG.
+
+ png_set_shift(png_ptr, &sig_bit);
+
+PNG files store 16 bit pixels in network byte order (big-endian,
+ie. most significant bits first). This code would be used if they are
+supplied the other way (little-endian, i.e. least significant bits
+first, the way PCs store them):
+
+ if (bit_depth > 8)
+ png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+ if (bit_depth < 8)
+ png_set_packswap(png_ptr);
+
+PNG files store 3 color pixels in red, green, blue order. This code
+would be used if they are supplied as blue, green, red:
+
+ png_set_bgr(png_ptr);
+
+PNG files describe monochrome as black being zero and white being
+one. This code would be used if the pixels are supplied with this reversed
+(black being one and white being zero):
+
+ png_set_invert_mono(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs. This is done by setting a callback
+with
+
+ png_set_write_user_transform_fn(png_ptr,
+ write_transform_fn);
+
+You must supply the function
+
+ void write_transform_fn(png_structp png_ptr ptr,
+ row_info_ptr row_info, png_bytep data)
+
+See pngtest.c for a working example. Your function will be called
+before any of the other transformations are processed. If supported
+libpng also supplies an information routine that may be called from
+your callback:
+
+ png_get_current_row_number(png_ptr);
+
+This returns the current row passed to the transform. Even with interlaced
+images the value returned is the row in the final output image.
+
+You can also set up a pointer to a user structure for use by your
+callback function.
+
+ png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
+
+The user_channels and user_depth parameters of this function are ignored
+when writing; you can set them to zero as shown.
+
+You can retrieve the pointer via the function png_get_user_transform_ptr().
+For example:
+
+ voidp write_user_transform_ptr =
+ png_get_user_transform_ptr(png_ptr);
+
+It is possible to have libpng flush any pending output, either manually,
+or automatically after a certain number of lines have been written. To
+flush the output stream a single time call:
+
+ png_write_flush(png_ptr);
+
+and to have libpng flush the output stream periodically after a certain
+number of scanlines have been written, call:
+
+ png_set_flush(png_ptr, nrows);
+
+Note that the distance between rows is from the last time png_write_flush()
+was called, or the first row of the image if it has never been called.
+So if you write 50 lines, and then png_set_flush 25, it will flush the
+output on the next scanline, and every 25 lines thereafter, unless
+png_write_flush() is called before 25 more lines have been written.
+If nrows is too small (less than about 10 lines for a 640 pixel wide
+RGB image) the image compression may decrease noticeably (although this
+may be acceptable for real-time applications). Infrequent flushing will
+only degrade the compression performance by a few percent over images
+that do not use flushing.
+
+.SS Writing the image data
+
+That's it for the transformations. Now you can write the image data.
+The simplest way to do this is in one function call. If you have the
+whole image in memory, you can just call png_write_image() and libpng
+will write the image. You will need to pass in an array of pointers to
+each row. This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() or call this function multiple
+times, or any of that other stuff necessary with png_write_rows().
+
+ png_write_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+ png_byte *row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to write the whole image at once, you can
+use png_write_rows() instead. If the file is not interlaced,
+this is simple:
+
+ png_write_rows(png_ptr, row_pointers,
+ number_of_rows);
+
+row_pointers is the same as in the png_write_image() call.
+
+If you are just writing one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+ png_bytep row_pointer = row;
+
+ png_write_row(png_ptr, row_pointer);
+
+When the file is interlaced, things can get a good deal more complicated.
+The only currently (as of the PNG Specification version 1.2, dated July
+1999) defined interlacing scheme for PNG files is the "Adam7" interlace
+scheme, that breaks down an image into seven smaller images of varying
+size. libpng will build these images for you, or you can do them
+yourself. If you want to build them yourself, see the PNG specification
+for details of which pixels to write when.
+
+If you don't want libpng to handle the interlacing details, just
+use png_set_interlace_handling() and call png_write_rows() the
+correct number of times to write all the sub-images
+(png_set_interlace_handling() returns the number of sub-images.)
+
+If you want libpng to build the sub-images, call this before you start
+writing any rows:
+
+ number_of_passes = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed. Currently, this is seven,
+but may change if another interlace type is added.
+
+Then write the complete image number_of_passes times.
+
+ png_write_rows(png_ptr, row_pointers, number_of_rows);
+
+Think carefully before you write an interlaced image. Typically code that
+reads such images reads all the image data into memory, uncompressed, before
+doing any processing. Only code that can display an image on the fly can
+take advantage of the interlacing and even then the image has to be exactly
+the correct size for the output device, because scaling an image requires
+adjacent pixels and these are not available until all the passes have been
+read.
+
+If you do write an interlaced image you will hardly ever need to handle
+the interlacing yourself. Call png_set_interlace_handling() and use the
+approach described above.
+
+The only time it is conceivable that you will really need to write an
+interlaced image pass-by-pass is when you have read one pass by pass and
+made some pixel-by-pixel transformation to it, as described in the read
+code above. In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
+to determine the size of each sub-image in turn and simply write the rows
+you obtained from the read code.
+
+.SS Finishing a sequential write
+
+After you are finished writing the image, you should finish writing
+the file. If you are interested in writing comments or time, you should
+pass an appropriately filled png_info pointer. If you are not interested,
+you can pass NULL.
+
+ png_write_end(png_ptr, info_ptr);
+
+When you are done, you can free all memory used by libpng like this:
+
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+ png_free_data(png_ptr, info_ptr, mask, seq)
+
+ mask - identifies data to be freed, a mask
+ containing the bitwise OR of one or
+ more of
+ PNG_FREE_PLTE, PNG_FREE_TRNS,
+ PNG_FREE_HIST, PNG_FREE_ICCP,
+ PNG_FREE_PCAL, PNG_FREE_ROWS,
+ PNG_FREE_SCAL, PNG_FREE_SPLT,
+ PNG_FREE_TEXT, PNG_FREE_UNKN,
+ or simply PNG_FREE_ALL
+
+ seq - sequence number of item to be freed
+ (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng, and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+If you allocated data such as a palette that you passed in to libpng
+with png_set_*, you must not free it until just before the call to
+png_destroy_write_struct().
+
+The default behavior is only to free data that was allocated internally
+by libpng. This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_zalloc() and passed in via a png_set_*() function, with
+
+ png_data_freer(png_ptr, info_ptr, freer, mask)
+
+ freer - one of
+ PNG_DESTROY_WILL_FREE_DATA
+ PNG_SET_WILL_FREE_DATA
+ PNG_USER_WILL_FREE_DATA
+
+ mask - which data elements are affected
+ same choices as in png_free_data()
+
+For example, to transfer responsibility for some data from a read structure
+to a write structure, you could use
+
+ png_data_freer(read_ptr, read_info_ptr,
+ PNG_USER_WILL_FREE_DATA,
+ PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+ png_data_freer(write_ptr, write_info_ptr,
+ PNG_DESTROY_WILL_FREE_DATA,
+ PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+thereby briefly reassigning responsibility for freeing to the user but
+immediately afterwards reassigning it once more to the write_destroy
+function. Having done this, it would then be safe to destroy the read
+structure and continue to use the PLTE, tRNS, and hIST data in the write
+structure.
+
+This function only affects data that has already been allocated.
+You can call this function before calling after the png_set_*() functions
+to control whether the user or png_destroy_*() is supposed to free the data.
+When the user assumes responsibility for libpng-allocated data, the
+application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_zalloc() to allocate it.
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key. Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+For a more compact example of writing a PNG image, see the file example.c.
+
+.SH V. Modifying/Customizing libpng:
+
+There are two issues here. The first is changing how libpng does
+standard things like memory allocation, input/output, and error handling.
+The second deals with more complicated things like adding new chunks,
+adding new transformations, and generally changing how libpng works.
+Both of those are compile-time issues; that is, they are generally
+determined at the time the code is written, and there is rarely a need
+to provide the user with a means of changing them.
+
+Memory allocation, input/output, and error handling
+
+All of the memory allocation, input/output, and error handling in libpng
+goes through callbacks that are user-settable. The default routines are
+in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, re