diff options
Diffstat (limited to 'src/3rdparty/libpng/pngrtran.c')
| -rw-r--r-- | src/3rdparty/libpng/pngrtran.c | 2508 |
1 files changed, 1658 insertions, 850 deletions
diff --git a/src/3rdparty/libpng/pngrtran.c b/src/3rdparty/libpng/pngrtran.c index e6e0c46b4d..5561852860 100644 --- a/src/3rdparty/libpng/pngrtran.c +++ b/src/3rdparty/libpng/pngrtran.c @@ -1,8 +1,8 @@ /* pngrtran.c - transforms the data in a row for PNG readers * - * Last changed in libpng 1.5.1 [February 3, 2011] - * Copyright (c) 1998-2011 Glenn Randers-Pehrson + * Last changed in libpng 1.5.10 [March 8, 2012] + * Copyright (c) 1998-2012 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * @@ -106,12 +106,18 @@ png_set_background_fixed(png_structp png_ptr, return; } - png_ptr->transformations |= PNG_BACKGROUND; + png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + png_memcpy(&(png_ptr->background), background_color, png_sizeof(png_color_16)); png_ptr->background_gamma = background_gamma; png_ptr->background_gamma_type = (png_byte)(background_gamma_code); - png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0); + if (need_expand) + png_ptr->transformations |= PNG_BACKGROUND_EXPAND; + else + png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND; } # ifdef PNG_FLOATING_POINT_SUPPORTED @@ -126,8 +132,25 @@ png_set_background(png_structp png_ptr, # endif /* FLOATING_POINT */ #endif /* READ_BACKGROUND */ -#ifdef PNG_READ_16_TO_8_SUPPORTED -/* Strip 16 bit depth files to 8 bit depth */ +/* Scale 16-bit depth files to 8-bit depth. If both of these are set then the + * one that pngrtran does first (scale) happens. This is necessary to allow the + * TRANSFORM and API behavior to be somewhat consistent, and it's simpler. + */ +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED +void PNGAPI +png_set_scale_16(png_structp png_ptr) +{ + png_debug(1, "in png_set_scale_16"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_SCALE_16_TO_8; +} +#endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED +/* Chop 16-bit depth files to 8-bit depth */ void PNGAPI png_set_strip_16(png_structp png_ptr) { @@ -149,12 +172,194 @@ png_set_strip_alpha(png_structp png_ptr) if (png_ptr == NULL) return; - png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; + png_ptr->transformations |= PNG_STRIP_ALPHA; } #endif +#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED) +static png_fixed_point +translate_gamma_flags(png_structp png_ptr, png_fixed_point output_gamma, + int is_screen) +{ + /* Check for flag values. The main reason for having the old Mac value as a + * flag is that it is pretty near impossible to work out what the correct + * value is from Apple documentation - a working Mac system is needed to + * discover the value! + */ + if (output_gamma == PNG_DEFAULT_sRGB || + output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB) + { + /* If there is no sRGB support this just sets the gamma to the standard + * sRGB value. (This is a side effect of using this function!) + */ +# ifdef PNG_READ_sRGB_SUPPORTED + png_ptr->flags |= PNG_FLAG_ASSUME_sRGB; +# endif + if (is_screen) + output_gamma = PNG_GAMMA_sRGB; + else + output_gamma = PNG_GAMMA_sRGB_INVERSE; + } + + else if (output_gamma == PNG_GAMMA_MAC_18 || + output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18) + { + if (is_screen) + output_gamma = PNG_GAMMA_MAC_OLD; + else + output_gamma = PNG_GAMMA_MAC_INVERSE; + } + + return output_gamma; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +static png_fixed_point +convert_gamma_value(png_structp png_ptr, double output_gamma) +{ + /* The following silently ignores cases where fixed point (times 100,000) + * gamma values are passed to the floating point API. This is safe and it + * means the fixed point constants work just fine with the floating point + * API. The alternative would just lead to undetected errors and spurious + * bug reports. Negative values fail inside the _fixed API unless they + * correspond to the flag values. + */ + if (output_gamma > 0 && output_gamma < 128) + output_gamma *= PNG_FP_1; + + /* This preserves -1 and -2 exactly: */ + output_gamma = floor(output_gamma + .5); + + if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN) + png_fixed_error(png_ptr, "gamma value"); + + return (png_fixed_point)output_gamma; +} +# endif +#endif /* READ_ALPHA_MODE || READ_GAMMA */ + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED +void PNGFAPI +png_set_alpha_mode_fixed(png_structp png_ptr, int mode, + png_fixed_point output_gamma) +{ + int compose = 0; + png_fixed_point file_gamma; + + png_debug(1, "in png_set_alpha_mode"); + + if (png_ptr == NULL) + return; + + output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/); + + /* Validate the value to ensure it is in a reasonable range. The value + * is expected to be 1 or greater, but this range test allows for some + * viewing correction values. The intent is to weed out users of this API + * who use the inverse of the gamma value accidentally! Since some of these + * values are reasonable this may have to be changed. + */ + if (output_gamma < 70000 || output_gamma > 300000) + png_error(png_ptr, "output gamma out of expected range"); + + /* The default file gamma is the inverse of the output gamma; the output + * gamma may be changed below so get the file value first: + */ + file_gamma = png_reciprocal(output_gamma); + + /* There are really 8 possibilities here, composed of any combination + * of: + * + * premultiply the color channels + * do not encode non-opaque pixels + * encode the alpha as well as the color channels + * + * The differences disappear if the input/output ('screen') gamma is 1.0, + * because then the encoding is a no-op and there is only the choice of + * premultiplying the color channels or not. + * + * png_set_alpha_mode and png_set_background interact because both use + * png_compose to do the work. Calling both is only useful when + * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along + * with a default gamma value. Otherwise PNG_COMPOSE must not be set. + */ + switch (mode) + { + case PNG_ALPHA_PNG: /* default: png standard */ + /* No compose, but it may be set by png_set_background! */ + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + break; + + case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */ + compose = 1; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + /* The output is linear: */ + output_gamma = PNG_FP_1; + break; + + case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */ + compose = 1; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA; + /* output_gamma records the encoding of opaque pixels! */ + break; + + case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */ + compose = 1; + png_ptr->transformations |= PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + break; + + default: + png_error(png_ptr, "invalid alpha mode"); + } + + /* Only set the default gamma if the file gamma has not been set (this has + * the side effect that the gamma in a second call to png_set_alpha_mode will + * be ignored.) + */ + if (png_ptr->gamma == 0) + png_ptr->gamma = file_gamma; + + /* But always set the output gamma: */ + png_ptr->screen_gamma = output_gamma; + + /* Finally, if pre-multiplying, set the background fields to achieve the + * desired result. + */ + if (compose) + { + /* And obtain alpha pre-multiplication by composing on black: */ + png_memset(&png_ptr->background, 0, sizeof png_ptr->background); + png_ptr->background_gamma = png_ptr->gamma; /* just in case */ + png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE; + png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND; + + if (png_ptr->transformations & PNG_COMPOSE) + png_error(png_ptr, + "conflicting calls to set alpha mode and background"); + + png_ptr->transformations |= PNG_COMPOSE; + } + + /* New API, make sure apps call the correct initializers: */ + png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_alpha_mode(png_structp png_ptr, int mode, double output_gamma) +{ + png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr, + output_gamma)); +} +# endif +#endif + #ifdef PNG_READ_QUANTIZE_SUPPORTED -/* Dither file to 8 bit. Supply a palette, the current number +/* Dither file to 8-bit. Supply a palette, the current number * of elements in the palette, the maximum number of elements * allowed, and a histogram if possible. If the current number * of colors is greater then the maximum number, the palette will be @@ -560,30 +765,6 @@ png_set_quantize(png_structp png_ptr, png_colorp palette, #endif /* PNG_READ_QUANTIZE_SUPPORTED */ #ifdef PNG_READ_GAMMA_SUPPORTED -/* Transform the image from the file_gamma to the screen_gamma. We - * only do transformations on images where the file_gamma and screen_gamma - * are not close reciprocals, otherwise it slows things down slightly, and - * also needlessly introduces small errors. - * - * We will turn off gamma transformation later if no semitransparent entries - * are present in the tRNS array for palette images. We can't do it here - * because we don't necessarily have the tRNS chunk yet. - */ -static int /* PRIVATE */ -png_gamma_threshold(png_fixed_point scrn_gamma, png_fixed_point file_gamma) -{ - /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma - * correction as a difference of the overall transform from 1.0 - * - * We want to compare the threshold with s*f - 1, if we get - * overflow here it is because of wacky gamma values so we - * turn on processing anyway. - */ - png_fixed_point gtest; - return !png_muldiv(>est, scrn_gamma, file_gamma, PNG_FP_1) || - png_gamma_significant(gtest); -} - void PNGFAPI png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma, png_fixed_point file_gamma) @@ -593,10 +774,32 @@ png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma, if (png_ptr == NULL) return; - if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) || - (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) || - png_gamma_threshold(scrn_gamma, file_gamma)) - png_ptr->transformations |= PNG_GAMMA; + /* New in libpng-1.5.4 - reserve particular negative values as flags. */ + scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/); + file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/); + +#if PNG_LIBPNG_VER >= 10600 + /* Checking the gamma values for being >0 was added in 1.5.4 along with the + * premultiplied alpha support; this actually hides an undocumented feature + * of the previous implementation which allowed gamma processing to be + * disabled in background handling. There is no evidence (so far) that this + * was being used; however, png_set_background itself accepted and must still + * accept '0' for the gamma value it takes, because it isn't always used. + * + * Since this is an API change (albeit a very minor one that removes an + * undocumented API feature) it will not be made until libpng-1.6.0. + */ + if (file_gamma <= 0) + png_error(png_ptr, "invalid file gamma in png_set_gamma"); + + if (scrn_gamma <= 0) + png_error(png_ptr, "invalid screen gamma in png_set_gamma"); +#endif + + /* Set the gamma values unconditionally - this overrides the value in the PNG + * file if a gAMA chunk was present. png_set_alpha_mode provides a + * different, easier, way to default the file gamma. + */ png_ptr->gamma = file_gamma; png_ptr->screen_gamma = scrn_gamma; } @@ -605,9 +808,8 @@ png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma, void PNGAPI png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma) { - png_set_gamma_fixed(png_ptr, - png_fixed(png_ptr, scrn_gamma, "png_set_gamma screen gamma"), - png_fixed(png_ptr, file_gamma, "png_set_gamma file gamma")); + png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma), + convert_gamma_value(png_ptr, file_gamma)); } # endif /* FLOATING_POINT_SUPPORTED */ #endif /* READ_GAMMA */ @@ -686,6 +888,26 @@ png_set_tRNS_to_alpha(png_structp png_ptr) } #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */ +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise + * it may not work correctly.) + */ +void PNGAPI +png_set_expand_16(png_structp png_ptr) +{ + png_debug(1, "in png_set_expand_16"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; + + /* New API, make sure apps call the correct initializers: */ + png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED; +} +#endif + #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED void PNGAPI png_set_gray_to_rgb(png_structp png_ptr) @@ -714,15 +936,15 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, switch(error_action) { - case 1: + case PNG_ERROR_ACTION_NONE: png_ptr->transformations |= PNG_RGB_TO_GRAY; break; - case 2: + case PNG_ERROR_ACTION_WARN: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; break; - case 3: + case PNG_ERROR_ACTION_ERROR: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; break; @@ -742,30 +964,43 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, } #endif { - png_uint_16 red_int, green_int; - if (red < 0 || green < 0) + if (red >= 0 && green >= 0 && red + green <= PNG_FP_1) { - red_int = 6968; /* .212671 * 32768 + .5 */ - green_int = 23434; /* .715160 * 32768 + .5 */ - } + png_uint_16 red_int, green_int; - else if (red + green < 100000L) - { - red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L); - green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L); + /* NOTE: this calculation does not round, but this behavior is retained + * for consistency, the inaccuracy is very small. The code here always + * overwrites the coefficients, regardless of whether they have been + * defaulted or set already. + */ + red_int = (png_uint_16)(((png_uint_32)red*32768)/100000); + green_int = (png_uint_16)(((png_uint_32)green*32768)/100000); + + png_ptr->rgb_to_gray_red_coeff = red_int; + png_ptr->rgb_to_gray_green_coeff = green_int; + png_ptr->rgb_to_gray_coefficients_set = 1; } else { - png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients"); - red_int = 6968; - green_int = 23434; + if (red >= 0 && green >= 0) + png_warning(png_ptr, + "ignoring out of range rgb_to_gray coefficients"); + + /* Use the defaults, from the cHRM chunk if set, else the historical + * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See + * png_do_rgb_to_gray for more discussion of the values. In this case + * the coefficients are not marked as 'set' and are not overwritten if + * something has already provided a default. + */ + if (png_ptr->rgb_to_gray_red_coeff == 0 && + png_ptr->rgb_to_gray_green_coeff == 0) + { + png_ptr->rgb_to_gray_red_coeff = 6968; + png_ptr->rgb_to_gray_green_coeff = 23434; + /* png_ptr->rgb_to_gray_blue_coeff = 2366; */ + } } - - png_ptr->rgb_to_gray_red_coeff = red_int; - png_ptr->rgb_to_gray_green_coeff = green_int; - png_ptr->rgb_to_gray_blue_coeff = - (png_uint_16)(32768 - red_int - green_int); } } @@ -807,167 +1042,513 @@ png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr } #endif +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +#ifdef PNG_READ_GAMMA_SUPPORTED +/* In the case of gamma transformations only do transformations on images where + * the [file] gamma and screen_gamma are not close reciprocals, otherwise it + * slows things down slightly, and also needlessly introduces small errors. + */ +static int /* PRIVATE */ +png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma) +{ + /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma + * correction as a difference of the overall transform from 1.0 + * + * We want to compare the threshold with s*f - 1, if we get + * overflow here it is because of wacky gamma values so we + * turn on processing anyway. + */ + png_fixed_point gtest; + return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) || + png_gamma_significant(gtest); +} +#endif + /* Initialize everything needed for the read. This includes modifying * the palette. */ -void /* PRIVATE */ -png_init_read_transformations(png_structp png_ptr) + +/*For the moment 'png_init_palette_transformations' and + * 'png_init_rgb_transformations' only do some flag canceling optimizations. + * The intent is that these two routines should have palette or rgb operations + * extracted from 'png_init_read_transformations'. + */ +static void /* PRIVATE */ +png_init_palette_transformations(png_structp png_ptr) { - png_debug(1, "in png_init_read_transformations"); + /* Called to handle the (input) palette case. In png_do_read_transformations + * the first step is to expand the palette if requested, so this code must + * take care to only make changes that are invariant with respect to the + * palette expansion, or only do them if there is no expansion. + * + * STRIP_ALPHA has already been handled in the caller (by setting num_trans + * to 0.) + */ + int input_has_alpha = 0; + int input_has_transparency = 0; - { -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ - defined(PNG_READ_SHIFT_SUPPORTED) || \ - defined(PNG_READ_GAMMA_SUPPORTED) - int color_type = png_ptr->color_type; -#endif + if (png_ptr->num_trans > 0) + { + int i; + + /* Ignore if all the entries are opaque (unlikely!) */ + for (i=0; i<png_ptr->num_trans; ++i) + if (png_ptr->trans_alpha[i] == 255) + continue; + else if (png_ptr->trans_alpha[i] == 0) + input_has_transparency = 1; + else + input_has_alpha = 1; + } + + /* If no alpha we can optimize. */ + if (!input_has_alpha) + { + /* Any alpha means background and associative alpha processing is + * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA + * and ENCODE_ALPHA are irrelevant. + */ + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + + if (!input_has_transparency) + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND); + } #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + /* png_set_background handling - deals with the complexity of whether the + * background color is in the file format or the screen format in the case + * where an 'expand' will happen. + */ -#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED - /* Detect gray background and attempt to enable optimization - * for gray --> RGB case - * - * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or - * RGB_ALPHA (in which case need_expand is superfluous anyway), the - * background color might actually be gray yet not be flagged as such. - * This is not a problem for the current code, which uses - * PNG_BACKGROUND_IS_GRAY only to decide when to do the - * png_do_gray_to_rgb() transformation. + /* The following code cannot be entered in the alpha pre-multiplication case + * because PNG_BACKGROUND_EXPAND is cancelled below. */ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && - !(color_type & PNG_COLOR_MASK_COLOR)) + (png_ptr->transformations & PNG_EXPAND)) { - png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; - } + { + png_ptr->background.red = + png_ptr->palette[png_ptr->background.index].red; + png_ptr->background.green = + png_ptr->palette[png_ptr->background.index].green; + png_ptr->background.blue = + png_ptr->palette[png_ptr->background.index].blue; + +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_ALPHA) + { + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + /* Invert the alpha channel (in tRNS) unless the pixels are + * going to be expanded, in which case leave it for later + */ + int i, istop = png_ptr->num_trans; + + for (i=0; i<istop; i++) + png_ptr->trans_alpha[i] = (png_byte)(255 - + png_ptr->trans_alpha[i]); + } + } +#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */ + } + } /* background expand and (therefore) no alpha association. */ +#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */ +} - else if ((png_ptr->transformations & PNG_BACKGROUND) && - !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && - (png_ptr->transformations & PNG_GRAY_TO_RGB) && - png_ptr->background.red == png_ptr->background.green && - png_ptr->background.red == png_ptr->background.blue) +static void /* PRIVATE */ +png_init_rgb_transformations(png_structp png_ptr) +{ + /* Added to libpng-1.5.4: check the color type to determine whether there + * is any alpha or transparency in the image and simply cancel the + * background and alpha mode stuff if there isn't. + */ + int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0; + int input_has_transparency = png_ptr->num_trans > 0; + + /* If no alpha we can optimize. */ + if (!input_has_alpha) { - png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; - png_ptr->background.gray = png_ptr->background.red; + /* Any alpha means background and associative alpha processing is + * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA + * and ENCODE_ALPHA are irrelevant. + */ +# ifdef PNG_READ_ALPHA_MODE_SUPPORTED + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; +# endif + + if (!input_has_transparency) + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND); } -#endif +#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + /* png_set_background handling - deals with the complexity of whether the + * background color is in the file format or the screen format in the case + * where an 'expand' will happen. + */ + + /* The following code cannot be entered in the alpha pre-multiplication case + * because PNG_BACKGROUND_EXPAND is cancelled below. + */ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && - (png_ptr->transformations & PNG_EXPAND)) + (png_ptr->transformations & PNG_EXPAND) && + !(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) + /* i.e., GRAY or GRAY_ALPHA */ { - if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */ { /* Expand background and tRNS chunks */ + int gray = png_ptr->background.gray; + int trans_gray = png_ptr->trans_color.gray; + switch (png_ptr->bit_depth) { case 1: - png_ptr->background.gray *= (png_uint_16)0xff; - png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; - if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) - { - png_ptr->trans_color.gray *= (png_uint_16)0xff; - png_ptr->trans_color.red = png_ptr->trans_color.green - = png_ptr->trans_color.blue = png_ptr->trans_color.gray; - } + gray *= 0xff; + trans_gray *= 0xff; break; case 2: - png_ptr->background.gray *= (png_uint_16)0x55; - png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; - if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) - { - png_ptr->trans_color.gray *= (png_uint_16)0x55; - png_ptr->trans_color.red = png_ptr->trans_color.green - = png_ptr->trans_color.blue = png_ptr->trans_color.gray; - } + gray *= 0x55; + trans_gray *= 0x55; break; case 4: - png_ptr->background.gray *= (png_uint_16)0x11; - png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; - if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) - { - png_ptr->trans_color.gray *= (png_uint_16)0x11; - png_ptr->trans_color.red = png_ptr->trans_color.green - = png_ptr->trans_color.blue = png_ptr->trans_color.gray; - } + gray *= 0x11; + trans_gray *= 0x11; break; default: case 8: + /* Already 8 bits, fall through */ case 16: - png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; + /* Already a full 16 bits */ break; } + + png_ptr->background.red = png_ptr->background.green = + png_ptr->background.blue = (png_uint_16)gray; + + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + png_ptr->trans_color.red = png_ptr->trans_color.green = + png_ptr->trans_color.blue = (png_uint_16)trans_gray; + } } - else if (color_type == PNG_COLOR_TYPE_PALETTE) - { - png_ptr->background.red = - png_ptr->palette[png_ptr->background.index].red; - png_ptr->background.green = - png_ptr->palette[png_ptr->background.index].green; - png_ptr->background.blue = - png_ptr->palette[png_ptr->background.index].blue; + } /* background expand and (therefore) no alpha association. */ +#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */ +} -#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED - if (png_ptr->transformations & PNG_INVERT_ALPHA) - { -#ifdef PNG_READ_EXPAND_SUPPORTED - if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) -#endif - { - /* Invert the alpha channel (in tRNS) unless the pixels are - * going to be expanded, in which case leave it for later - */ - int i, istop; - istop=(int)png_ptr->num_trans; - for (i=0; i<istop; i++) - png_ptr->trans_alpha[i] = (png_byte)(255 - - png_ptr->trans_alpha[i]); - } - } -#endif +void /* PRIVATE */ +png_init_read_transformations(png_structp png_ptr) +{ + png_debug(1, "in png_init_read_transformations"); + + /* This internal function is called from png_read_start_row in pngrutil.c + * and it is called before the 'rowbytes' calculation is done, so the code + * in here can change or update the transformations flags. + * + * First do updates that do not depend on the details of the PNG image data + * being processed. + */ +#ifdef PNG_READ_GAMMA_SUPPORTED + /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds + * png_set_alpha_mode and this is another source for a default file gamma so + * the test needs to be performed later - here. In addition prior to 1.5.4 + * the tests were repeated for the PALETTE color type here - this is no + * longer necessary (and doesn't seem to have been necessary before.) + */ + { + /* The following temporary indicates if overall gamma correction is + * required. + */ + int gamma_correction = 0; + + if (png_ptr->gamma != 0) /* has been set */ + { + if (png_ptr->screen_gamma != 0) /* screen set too */ + gamma_correction = png_gamma_threshold(png_ptr->gamma, + png_ptr->screen_gamma); + + else + /* Assume the output matches the input; a long time default behavior + * of libpng, although the standard has nothing to say about this. + */ + png_ptr->screen_gamma = png_reciprocal(png_ptr->gamma); } + + else if (png_ptr->screen_gamma != 0) + /* The converse - assume the file matches the screen, note that this + * perhaps undesireable default can (from 1.5.4) be changed by calling + * png_set_alpha_mode (even if the alpha handling mode isn't required + * or isn't changed from the default.) + */ + png_ptr->gamma = png_reciprocal(png_ptr->screen_gamma); + + else /* neither are set */ + /* Just in case the following prevents any processing - file and screen + * are both assumed to be linear and there is no way to introduce a + * third gamma value other than png_set_background with 'UNIQUE', and, + * prior to 1.5.4 + */ + png_ptr->screen_gamma = png_ptr->gamma = PNG_FP_1; + + /* Now turn the gamma transformation on or off as appropriate. Notice + * that PNG_GAMMA just refers to the file->screen correction. Alpha + * composition may independently cause gamma correction because it needs + * linear data (e.g. if the file has a gAMA chunk but the screen gamma + * hasn't been specified.) In any case this flag may get turned off in + * the code immediately below if the transform can be handled outside the + * row loop. + */ + if (gamma_correction) + png_ptr->transformations |= PNG_GAMMA; + + else + png_ptr->transformations &= ~PNG_GAMMA; } #endif -#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED) - png_ptr->background_1 = png_ptr->background; + /* Certain transformations have the effect of preventing other + * transformations that happen afterward in png_do_read_transformations, + * resolve the interdependencies here. From the code of + * png_do_read_transformations the order is: + * + * 1) PNG_EXPAND (including PNG_EXPAND_tRNS) + * 2) PNG_STRIP_ALPHA (if no compose) + * 3) PNG_RGB_TO_GRAY + * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY + * 5) PNG_COMPOSE + * 6) PNG_GAMMA + * 7) PNG_STRIP_ALPHA (if compose) + * 8) PNG_ENCODE_ALPHA + * 9) PNG_SCALE_16_TO_8 + * 10) PNG_16_TO_8 + * 11) PNG_QUANTIZE (converts to palette) + * 12) PNG_EXPAND_16 + * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY + * 14) PNG_INVERT_MONO + * 15) PNG_SHIFT + * 16) PNG_PACK + * 17) PNG_BGR + * 18) PNG_PACKSWAP + * 19) PNG_FILLER (includes PNG_ADD_ALPHA) + * 20) PNG_INVERT_ALPHA + * 21) PNG_SWAP_ALPHA + * 22) PNG_SWAP_BYTES + * 23) PNG_USER_TRANSFORM [must be last] + */ +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + !(png_ptr->transformations & PNG_COMPOSE)) + { + /* Stripping the alpha channel happens immediately after the 'expand' + * transformations, before all other transformation, so it cancels out + * the alpha handling. It has the side effect negating the effect of + * PNG_EXPAND_tRNS too: + */ + png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA | + PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + + /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen + * so transparency information would remain just so long as it wasn't + * expanded. This produces unexpected API changes if the set of things + * that do PNG_EXPAND_tRNS changes (perfectly possible given the + * documentation - which says ask for what you want, accept what you + * get.) This makes the behavior consistent from 1.5.4: + */ + png_ptr->num_trans = 0; + } +#endif /* STRIP_ALPHA supported, no COMPOSE */ + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED + /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA + * settings will have no effect. + */ + if (!png_gamma_significant(png_ptr->screen_gamma)) + { + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + } #endif -#ifdef PNG_READ_GAMMA_SUPPORTED - if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0) - && png_gamma_threshold(png_ptr->screen_gamma, png_ptr->gamma)) +#if defined(PNG_READ_EXPAND_SUPPORTED) && \ + defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) + /* Detect gray background and attempt to enable optimization for + * gray --> RGB case. + * + * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or + * RGB_ALPHA (in which case need_expand is superfluous anyway), the + * background color might actually be gray yet not be flagged as such. + * This is not a problem for the current code, which uses + * PNG_BACKGROUND_IS_GRAY only to decide when to do the + * png_do_gray_to_rgb() transformation. + * + * TODO: this code needs to be revised to avoid the complexity and + * interdependencies. The color type of the background should be recorded in + * png_set_background, along with the bit depth, then the code has a record + * of exactly what color space the background is currently in. + */ + if (png_ptr->transformations & PNG_BACKGROUND_EXPAND) + { + /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if + * the file was grayscale the background value is gray. + */ + if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + } + + else if (png_ptr->transformations & PNG_COMPOSE) { - int i, k; - k=0; - for (i=0; i<png_ptr->num_trans; i++) + /* PNG_COMPOSE: png_set_background was called with need_expand false, + * so the color is in the color space of the output or png_set_alpha_mode + * was called and the color is black. Ignore RGB_TO_GRAY because that + * happens before GRAY_TO_RGB. + */ + if (png_ptr->transformations & PNG_GRAY_TO_RGB) { - if (png_ptr->trans_alpha[i] != 0 && png_ptr->trans_alpha[i] != 0xff) - k=1; /* Partial transparency is present */ + if (png_ptr->background.red == png_ptr->background.green && + png_ptr->background.red == png_ptr->background.blue) + { + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + png_ptr->background.gray = png_ptr->background.red; + } } - if (k == 0) - png_ptr->transformations &= ~PNG_GAMMA; } +#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED (etc) */ + + /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations + * can be performed directly on the palette, and some (such as rgb to gray) + * can be optimized inside the palette. This is particularly true of the + * composite (background and alpha) stuff, which can be pretty much all done + * in the palette even if the result is expanded to RGB or gray afterward. + * + * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and + * earlier and the palette stuff is actually handled on the first row. This + * leads to the reported bug that the palette returned by png_get_PLTE is not + * updated. + */ + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + png_init_palette_transformations(png_ptr); - if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) && - png_ptr->gamma != 0) + else + png_init_rgb_transformations(png_ptr); + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + defined(PNG_READ_EXPAND_16_SUPPORTED) + if ((png_ptr->transformations & PNG_EXPAND_16) && + (png_ptr->transformations & PNG_COMPOSE) && + !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + png_ptr->bit_depth != 16) + { + /* TODO: fix this. Because the expand_16 operation is after the compose + * handling the background color must be 8, not 16, bits deep, but the + * application will supply a 16-bit value so reduce it here. + * + * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at + * present, so that case is ok (until do_expand_16 is moved.) + * + * NOTE: this discards the low 16 bits of the user supplied background + * color, but until expand_16 works properly there is no choice! + */ +# define CHOP(x) (x)=((png_uint_16)(((png_uint_32)(x)*255+32895) >> 16)) + CHOP(png_ptr->background.red); + CHOP(png_ptr->background.green); + CHOP(png_ptr->background.blue); + CHOP(png_ptr->background.gray); +# undef CHOP + } +#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */ + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \ + defined(PNG_READ_STRIP_16_TO_8_SUPPORTED)) + if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) && + (png_ptr->transformations & PNG_COMPOSE) && + !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + png_ptr->bit_depth == 16) + { + /* On the other hand, if a 16-bit file is to be reduced to 8-bits per + * component this will also happen after PNG_COMPOSE and so the background + * color must be pre-expanded here. + * + * TODO: fix this too. + */ + png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257); + png_ptr->background.green = + (png_uint_16)(png_ptr->background.green * 257); + png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257); + png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257); + } +#endif + + /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the + * background support (see the comments in scripts/pnglibconf.dfa), this + * allows pre-multiplication of the alpha channel to be implemented as + * compositing on black. This is probably sub-optimal and has been done in + * 1.5.4 betas simply to enable external critique and testing (i.e. to + * implement the new API quickly, without lots of internal changes.) + */ + +#ifdef PNG_READ_GAMMA_SUPPORTED +# ifdef PNG_READ_BACKGROUND_SUPPORTED + /* Includes ALPHA_MODE */ + png_ptr->background_1 = png_ptr->background; +# endif + + /* This needs to change - in the palette image case a whole set of tables are + * built when it would be quicker to just calculate the correct value for + * each palette entry directly. Also, the test is too tricky - why check + * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that + * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the + * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction + * the gamma tables will not be built even if composition is required on a + * gamma encoded value. + * + * In 1.5.4 this is addressed below by an additional check on the individual + * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the + * tables. + */ + if ((png_ptr->transformations & PNG_GAMMA) + || ((png_ptr->transformations & PNG_RGB_TO_GRAY) + && (png_gamma_significant(png_ptr->gamma) || + png_gamma_significant(png_ptr->screen_gamma))) + || ((png_ptr->transformations & PNG_COMPOSE) + && (png_gamma_significant(png_ptr->gamma) + || png_gamma_significant(png_ptr->screen_gamma) +# ifdef PNG_READ_BACKGROUND_SUPPORTED + || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE + && png_gamma_significant(png_ptr->background_gamma)) +# endif + )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) + && png_gamma_significant(png_ptr->screen_gamma)) + ) { png_build_gamma_table(png_ptr, png_ptr->bit_depth); #ifdef PNG_READ_BACKGROUND_SUPPORTED - if (png_ptr->transformations & PNG_BACKGROUND) + if (png_ptr->transformations & PNG_COMPOSE) { - if (color_type == PNG_COLOR_TYPE_PALETTE) + /* Issue a warning about this combination: because RGB_TO_GRAY is + * optimized to do the gamma transform if present yet do_background has + * to do the same thing if both options are set a + * double-gamma-correction happens. This is true in all versions of + * libpng to date. + */ + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + png_warning(png_ptr, + "libpng does not support gamma+background+rgb_to_gray"); + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { - /* Could skip if no transparency */ + /* We don't get to here unless there is a tRNS chunk with non-opaque + * entries - see the checking code at the start of this function. + */ png_color back, back_1; png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; @@ -1013,26 +1594,39 @@ png_init_read_transformations(png_structp png_ptr) if (png_gamma_significant(gs)) { + back.red = png_gamma_8bit_correct(png_ptr->background.red, + gs); + back.green = png_gamma_8bit_correct(png_ptr->background.green, + gs); + back.blue = png_gamma_8bit_correct(png_ptr->background.blue, + gs); + } + + else + { back.red = (png_byte)png_ptr->background.red; back.green = (png_byte)png_ptr->background.green; back.blue = (png_byte)png_ptr->background.blue; } + if (png_gamma_significant(g)) + { + back_1.red = png_gamma_8bit_correct(png_ptr->background.red, + g); + back_1.green = png_gamma_8bit_correct( + png_ptr->background.green, g); + back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue, + g); + } + else { - back.red = png_gamma_8bit_correct(png_ptr->background.red, - gs); - back.green = png_gamma_8bit_correct(png_ptr->background.green, - gs); - back.blue = png_gamma_8bit_correct(png_ptr->background.blue, - gs); + back_1.red = (png_byte)png_ptr->background.red; + back_1.green = (png_byte)png_ptr->background.green; + back_1.blue = (png_byte)png_ptr->background.blue; } - back_1.red = png_gamma_8bit_correct(png_ptr->background.red, g); - back_1.green = png_gamma_8bit_correct(png_ptr->background.green, - g); - back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue, - g); } + for (i = 0; i < num_palette; i++) { if (i < (int)png_ptr->num_trans && @@ -1066,22 +1660,22 @@ png_init_read_transformations(png_structp png_ptr) palette[i].blue = png_ptr->gamma_table[palette[i].blue]; } } - /* Prevent the transformations being done again, and make sure - * that the now spurious alpha channel is stripped - the code - * has just reduced background composition and gamma correction - * to a simple alpha channel strip. + + /* Prevent the transformations being done again. + * + * NOTE: this is highly dubious; it removes the transformations in + * place. This seems inconsistent with the general treatment of the + * transformations elsewhere. */ - png_ptr->transformations &= ~PNG_BACKGROUND; - png_ptr->transformations &= ~PNG_GAMMA; - png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; - } + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA); + } /* color_type == PNG_COLOR_TYPE_PALETTE */ /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */ - else - /* color_type != PNG_COLOR_TYPE_PALETTE */ + else /* color_type != PNG_COLOR_TYPE_PALETTE */ { - png_fixed_point g = PNG_FP_1; - png_fixed_point gs = PNG_FP_1; + int gs_sig, g_sig; + png_fixed_point g = PNG_FP_1; /* Correction to linear */ + png_fixed_point gs = PNG_FP_1; /* Correction to screen */ switch (png_ptr->background_gamma_type) { @@ -1105,34 +1699,45 @@ png_init_read_transformations(png_structp png_ptr) png_error(png_ptr, "invalid background gamma type"); } - png_ptr->background_1.gray = png_gamma_correct(png_ptr, - png_ptr->background.gray, g); + g_sig = png_gamma_significant(g); + gs_sig = png_gamma_significant(gs); + + if (g_sig) + png_ptr->background_1.gray = png_gamma_correct(png_ptr, + png_ptr->background.gray, g); - png_ptr->background.gray = png_gamma_correct(png_ptr, - png_ptr->background.gray, gs); + if (gs_sig) + png_ptr->background.gray = png_gamma_correct(png_ptr, + png_ptr->background.gray, gs); if ((png_ptr->background.red != png_ptr->background.green) || (png_ptr->background.red != png_ptr->background.blue) || (png_ptr->background.red != png_ptr->background.gray)) { /* RGB or RGBA with color background */ - png_ptr->background_1.red = png_gamma_correct(png_ptr, - png_ptr->background.red, g); + if (g_sig) + { + png_ptr->background_1.red = png_gamma_correct(png_ptr, + png_ptr->background.red, g); - png_ptr->background_1.green = png_gamma_correct(png_ptr, - png_ptr->background.green, g); + png_ptr->background_1.green = png_gamma_correct(png_ptr, + png_ptr->background.green, g); - png_ptr->background_1.blue = png_gamma_correct(png_ptr, - png_ptr->background.blue, g); + png_ptr->background_1.blue = png_gamma_correct(png_ptr, + png_ptr->background.blue, g); + } - png_ptr->background.red = png_gamma_correct(png_ptr, - png_ptr->background.red, gs); + if (gs_sig) + { + png_ptr->background.red = png_gamma_correct(png_ptr, + png_ptr->background.red, gs); - png_ptr->background.green = png_gamma_correct(png_ptr, - png_ptr->background.green, gs); + png_ptr->background.green = png_gamma_correct(png_ptr, + png_ptr->background.green, gs); - png_ptr->background.blue = png_gamma_correct(png_ptr, - png_ptr->background.blue, gs); + png_ptr->background.blue = png_gamma_correct(png_ptr, + png_ptr->background.blue, gs); + } } else @@ -1144,17 +1749,30 @@ png_init_read_transformations(png_structp png_ptr) png_ptr->background.red = png_ptr->background.green = png_ptr->background.blue = png_ptr->background.gray; } - } - } + + /* The background is now in screen gamma: */ + png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN; + } /* color_type != PNG_COLOR_TYPE_PALETTE */ + }/* png_ptr->transformations & PNG_BACKGROUND */ + else /* Transformation does not include PNG_BACKGROUND */ #endif /* PNG_READ_BACKGROUND_SUPPORTED */ - if (color_type == PNG_COLOR_TYPE_PALETTE) + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + /* RGB_TO_GRAY needs to have non-gamma-corrected values! */ + && ((png_ptr->transformations & PNG_EXPAND) == 0 || + (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0) +#endif + ) { png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; int i; + /*NOTE: there are other transformations that should probably be in here + * too. + */ for (i = 0; i < num_palette; i++) { palette[i].red = png_ptr->gamma_table[palette[i].red]; @@ -1164,16 +1782,17 @@ png_init_read_transformations(png_structp png_ptr) /* Done the gamma correction. */ png_ptr->transformations &= ~PNG_GAMMA; - } + } /* color_type == PALETTE && !PNG_BACKGROUND transformation */ } #ifdef PNG_READ_BACKGROUND_SUPPORTED else #endif #endif /* PNG_READ_GAMMA_SUPPORTED */ + #ifdef PNG_READ_BACKGROUND_SUPPORTED - /* No GAMMA transformation */ - if ((png_ptr->transformations & PNG_BACKGROUND) && - (color_type == PNG_COLOR_TYPE_PALETTE)) + /* No GAMMA transformation (see the hanging else 4 lines above) */ + if ((png_ptr->transformations & PNG_COMPOSE) && + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) { int i; int istop = (int)png_ptr->num_trans; @@ -1205,45 +1824,52 @@ png_init_read_transformations(png_structp png_ptr) } } - /* Handled alpha, still need to strip the channel. */ - png_ptr->transformations &= ~PNG_BACKGROUND; - png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; + png_ptr->transformations &= ~PNG_COMPOSE; } #endif /* PNG_READ_BACKGROUND_SUPPORTED */ #ifdef PNG_READ_SHIFT_SUPPORTED if ((png_ptr->transformations & PNG_SHIFT) && - (color_type == PNG_COLOR_TYPE_PALETTE)) + !(png_ptr->transformations & PNG_EXPAND) && + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) { - png_uint_16 i; - png_uint_16 istop = png_ptr->num_palette; - int sr = 8 - png_ptr->sig_bit.red; - int sg = 8 - png_ptr->sig_bit.green; - int sb = 8 - png_ptr->sig_bit.blue; + int i; + int istop = png_ptr->num_palette; + int shift = 8 - png_ptr->sig_bit.red; - if (sr < 0 || sr > 8) - sr = 0; + png_ptr->transformations &= ~PNG_SHIFT; - if (sg < 0 || sg > 8) - sg = 0; + /* significant bits can be in the range 1 to 7 for a meaninful result, if + * the number of significant bits is 0 then no shift is done (this is an + * error condition which is silently ignored.) + */ + if (shift > 0 && shift < 8) for (i=0; i<istop; ++i) + { + int component = png_ptr->palette[i].red; - if (sb < 0 || sb > 8) - sb = 0; + component >>= shift; + png_ptr->palette[i].red = (png_byte)component; + } - for (i = 0; i < istop; i++) + shift = 8 - png_ptr->sig_bit.green; + if (shift > 0 && shift < 8) for (i=0; i<istop; ++i) { - png_ptr->palette[i].red >>= sr; - png_ptr->palette[i].green >>= sg; - png_ptr->palette[i].blue >>= sb; + int component = png_ptr->palette[i].green; + + component >>= shift; + png_ptr->palette[i].green = (png_byte)component; + } + + shift = 8 - png_ptr->sig_bit.blue; + if (shift > 0 && shift < 8) for (i=0; i<istop; ++i) + { + int component = png_ptr->palette[i].blue; + + component >>= shift; + png_ptr->palette[i].blue = (png_byte)component; } } #endif /* PNG_READ_SHIFT_SUPPORTED */ - } -#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \ - && !defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr) - return; -#endif } /* Modify the info structure to reflect the transformations. The @@ -1260,8 +1886,11 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) { if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { - if (png_ptr->num_trans && - (png_ptr->transformations & PNG_EXPAND_tRNS)) + /* This check must match what actually happens in + * png_do_expand_palette; if it ever checks the tRNS chunk to see if + * it is all opaque we must do the same (at present it does not.) + */ + if (png_ptr->num_trans > 0) info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA; else @@ -1285,45 +1914,72 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) } #endif -#ifdef PNG_READ_BACKGROUND_SUPPORTED - if (png_ptr->transformations & PNG_BACKGROUND) - { - info_ptr->color_type = (png_byte)(info_ptr->color_type & - ~PNG_COLOR_MASK_ALPHA); - info_ptr->num_trans = 0; +#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) + /* The following is almost certainly wrong unless the background value is in + * the screen space! + */ + if (png_ptr->transformations & PNG_COMPOSE) info_ptr->background = png_ptr->background; - } #endif #ifdef PNG_READ_GAMMA_SUPPORTED - if (png_ptr->transformations & PNG_GAMMA) - { - info_ptr->gamma = png_ptr->gamma; - } + /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4), + * however it seems that the code in png_init_read_transformations, which has + * been called before this from png_read_update_info->png_read_start_row + * sometimes does the gamma transform and cancels the flag. + */ + info_ptr->gamma = png_ptr->gamma; #endif -#ifdef PNG_READ_16_TO_8_SUPPORTED -#ifdef PNG_READ_16BIT_SUPPORTED - if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16)) - info_ptr->bit_depth = 8; -#else - /* Force chopping 16-bit input down to 8 */ if (info_ptr->bit_depth == 16) { - png_ptr->transformations |=PNG_16_TO_8; - info_ptr->bit_depth = 8; +# ifdef PNG_READ_16BIT_SUPPORTED +# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + info_ptr->bit_depth = 8; +# endif + +# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_16_TO_8) + info_ptr->bit_depth = 8; +# endif + +# else + /* No 16 bit support: force chopping 16-bit input down to 8, in this case + * the app program can chose if both APIs are available by setting the + * correct scaling to use. + */ +# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + /* For compatibility with previous versions use the strip method by + * default. This code works because if PNG_SCALE_16_TO_8 is already + * set the code below will do that in preference to the chop. + */ + png_ptr->transformations |= PNG_16_TO_8; + info_ptr->bit_depth = 8; +# else + +# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + png_ptr->transformations |= PNG_SCALE_16_TO_8; + info_ptr->bit_depth = 8; +# else + + CONFIGURATION ERROR: you must enable at least one 16 to 8 method +# endif +# endif +#endif /* !READ_16BIT_SUPPORTED */ } -#endif -#endif #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED if (png_ptr->transformations & PNG_GRAY_TO_RGB) - info_ptr->color_type |= PNG_COLOR_MASK_COLOR; + info_ptr->color_type = (png_byte)(info_ptr->color_type | + PNG_COLOR_MASK_COLOR); #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED if (png_ptr->transformations & PNG_RGB_TO_GRAY) - info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR; + info_ptr->color_type = (png_byte)(info_ptr->color_type & + ~PNG_COLOR_MASK_COLOR); #endif #ifdef PNG_READ_QUANTIZE_SUPPORTED @@ -1338,6 +1994,14 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) } #endif +#ifdef PNG_READ_EXPAND_16_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 && + info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) + { + info_ptr->bit_depth = 16; + } +#endif + #ifdef PNG_READ_PACK_SUPPORTED if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8)) info_ptr->bit_depth = 8; @@ -1353,8 +2017,12 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) info_ptr->channels = 1; #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED - if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA) - info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; + if (png_ptr->transformations & PNG_STRIP_ALPHA) + { + info_ptr->color_type = (png_byte)(info_ptr->color_type & + ~PNG_COLOR_MASK_ALPHA); + info_ptr->num_trans = 0; + } #endif if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) @@ -1390,6 +2058,14 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED) info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width); + /* Adding in 1.5.4: cache the above value in png_struct so that we can later + * check in png_rowbytes that the user buffer won't get overwritten. Note + * that the field is not always set - if png_read_update_info isn't called + * the application has to either not do any transforms or get the calculation + * right itself. + */ + png_ptr->info_rowbytes = info_ptr->rowbytes; + #ifndef PNG_READ_EXPAND_SUPPORTED if (png_ptr) return; @@ -1401,69 +2077,71 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED) * decide how it fits in with the other transformations here. */ void /* PRIVATE */ -png_do_read_transformations(png_structp png_ptr) +png_do_read_transformations(png_structp png_ptr, png_row_infop row_info) { png_debug(1, "in png_do_read_transformations"); if (png_ptr->row_buf == NULL) { -#ifdef PNG_CONSOLE_IO_SUPPORTED - char msg[50]; - - png_snprintf2(msg, 50, - "NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number, - png_ptr->pass); - png_error(png_ptr, msg); -#else + /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this + * error is incredibly rare and incredibly easy to debug without this + * information. + */ png_error(png_ptr, "NULL row buffer"); -#endif } -#ifdef PNG_WARN_UNINITIALIZED_ROW - if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) - /* Application has failed to call either png_read_start_image() - * or png_read_update_info() after setting transforms that expand - * pixels. This check added to libpng-1.2.19 + + /* The following is debugging; prior to 1.5.4 the code was never compiled in; + * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro + * PNG_WARN_UNINITIALIZED_ROW removed. In 1.5 the new flag is set only for + * selected new APIs to ensure that there is no API change. + */ + if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 && + !(png_ptr->flags & PNG_FLAG_ROW_INIT)) + { + /* Application has failed to call either png_read_start_image() or + * png_read_update_info() after setting transforms that expand pixels. + * This check added to libpng-1.2.19 (but not enabled until 1.5.4). */ -#if (PNG_WARN_UNINITIALIZED_ROW==1) png_error(png_ptr, "Uninitialized row"); -#else - png_warning(png_ptr, "Uninitialized row"); -#endif -#endif + } #ifdef PNG_READ_EXPAND_SUPPORTED if (png_ptr->transformations & PNG_EXPAND) { - if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE) + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) { - png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_do_expand_palette(row_info, png_ptr->row_buf + 1, png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans); } + else { if (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND_tRNS)) - png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_do_expand(row_info, png_ptr->row_buf + 1, &(png_ptr->trans_color)); - else - png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, + else + png_do_expand(row_info, png_ptr->row_buf + 1, NULL); } } #endif #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED - if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA) - png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, - PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)); + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + !(png_ptr->transformations & PNG_COMPOSE) && + (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(row_info, png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED if (png_ptr->transformations & PNG_RGB_TO_GRAY) { int rgb_error = - png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), + png_do_rgb_to_gray(png_ptr, row_info, png_ptr->row_buf + 1); if (rgb_error) @@ -1517,107 +2195,146 @@ png_do_read_transformations(png_structp png_ptr) */ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) - png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1); #endif -#ifdef PNG_READ_BACKGROUND_SUPPORTED - if ((png_ptr->transformations & PNG_BACKGROUND) && - ((png_ptr->num_trans != 0) || - (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) - png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1, - &(png_ptr->trans_color), &(png_ptr->background) -#ifdef PNG_READ_GAMMA_SUPPORTED - , &(png_ptr->background_1), - png_ptr->gamma_table, png_ptr->gamma_from_1, - png_ptr->gamma_to_1, png_ptr->gamma_16_table, - png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1, - png_ptr->gamma_shift -#endif - ); +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) + if (png_ptr->transformations & PNG_COMPOSE) + png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr); #endif #ifdef PNG_READ_GAMMA_SUPPORTED if ((png_ptr->transformations & PNG_GAMMA) && -#ifdef PNG_READ_BACKGROUND_SUPPORTED - !((png_ptr->transformations & PNG_BACKGROUND) && +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + /* Because RGB_TO_GRAY does the gamma transform. */ + !(png_ptr->transformations & PNG_RGB_TO_GRAY) && +#endif +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) + /* Because PNG_COMPOSE does the gamma transform if there is something to + * do (if there is an alpha channel or transparency.) + */ + !((png_ptr->transformations & PNG_COMPOSE) && ((png_ptr->num_trans != 0) || (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && #endif + /* Because png_init_read_transformations transforms the palette, unless + * RGB_TO_GRAY will do the transform. + */ (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)) - png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1, - png_ptr->gamma_table, png_ptr->gamma_16_table, - png_ptr->gamma_shift); + png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr); +#endif + +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + (png_ptr->transformations & PNG_COMPOSE) && + (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(row_info, png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); +#endif + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED + if ((png_ptr->transformations & PNG_ENCODE_ALPHA) && + (row_info->color_type & PNG_COLOR_MASK_ALPHA)) + png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr); +#endif + +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1); #endif -#ifdef PNG_READ_16_TO_8_SUPPORTED +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + /* There is no harm in doing both of these because only one has any effect, + * by putting the 'scale' option first if the app asks for scale (either by + * calling the API or in a TRANSFORM flag) this is what happens. + */ if (png_ptr->transformations & PNG_16_TO_8) - png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_chop(row_info, png_ptr->row_buf + 1); #endif #ifdef PNG_READ_QUANTIZE_SUPPORTED if (png_ptr->transformations & PNG_QUANTIZE) { - png_do_quantize(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_do_quantize(row_info, png_ptr->row_buf + 1, png_ptr->palette_lookup, png_ptr->quantize_index); - if (png_ptr->row_info.rowbytes == 0) + if (row_info->rowbytes == 0) png_error(png_ptr, "png_do_quantize returned rowbytes=0"); } #endif /* PNG_READ_QUANTIZE_SUPPORTED */ +#ifdef PNG_READ_EXPAND_16_SUPPORTED + /* Do the expansion now, after all the arithmetic has been done. Notice + * that previous transformations can handle the PNG_EXPAND_16 flag if this + * is efficient (particularly true in the case of gamma correction, where + * better accuracy results faster!) + */ + if (png_ptr->transformations & PNG_EXPAND_16) + png_do_expand_16(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + /*NOTE: moved here in 1.5.4 (from much later in this list.) */ + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && + (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) + png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1); +#endif + #ifdef PNG_READ_INVERT_SUPPORTED if (png_ptr->transformations & PNG_INVERT_MONO) - png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_invert(row_info, png_ptr->row_buf + 1); #endif #ifdef PNG_READ_SHIFT_SUPPORTED if (png_ptr->transformations & PNG_SHIFT) - png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_do_unshift(row_info, png_ptr->row_buf + 1, &(png_ptr->shift)); #endif #ifdef PNG_READ_PACK_SUPPORTED if (png_ptr->transformations & PNG_PACK) - png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_unpack(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED + /* Added at libpng-1.5.10 */ + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) + png_do_check_palette_indexes(png_ptr, row_info); #endif #ifdef PNG_READ_BGR_SUPPORTED if (png_ptr->transformations & PNG_BGR) - png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_bgr(row_info, png_ptr->row_buf + 1); #endif #ifdef PNG_READ_PACKSWAP_SUPPORTED if (png_ptr->transformations & PNG_PACKSWAP) - png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED - /* If gray -> RGB, do so now only if we did not do so above */ - if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && - (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) - png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_packswap(row_info, png_ptr->row_buf + 1); #endif #ifdef PNG_READ_FILLER_SUPPORTED if (png_ptr->transformations & PNG_FILLER) - png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_do_read_filler(row_info, png_ptr->row_buf + 1, (png_uint_32)png_ptr->filler, png_ptr->flags); #endif #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_INVERT_ALPHA) - png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1); #endif #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_SWAP_ALPHA) - png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1); #endif #ifdef PNG_READ_16BIT_SUPPORTED #ifdef PNG_READ_SWAP_SUPPORTED if (png_ptr->transformations & PNG_SWAP_BYTES) - png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_swap(row_info, png_ptr->row_buf + 1); #endif #endif @@ -1626,8 +2343,8 @@ png_do_read_transformations(png_structp png_ptr) { if (png_ptr->read_user_transform_fn != NULL) (*(png_ptr->read_user_transform_fn)) /* User read transform function */ - (png_ptr, /* png_ptr */ - &(png_ptr->row_info), /* row_info: */ + (png_ptr, /* png_ptr */ + row_info, /* row_info: */ /* png_uint_32 width; width of row */ /* png_size_t rowbytes; number of bytes in row */ /* png_byte color_type; color type of pixels */ @@ -1637,19 +2354,17 @@ png_do_read_transformations(png_structp png_ptr) png_ptr->row_buf + 1); /* start of pixel data for row */ #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED if (png_ptr->user_transform_depth) - png_ptr->row_info.bit_depth = png_ptr->user_transform_depth; + row_info->bit_depth = png_ptr->user_transform_depth; if (png_ptr->user_transform_channels) - png_ptr->row_info.channels = png_ptr->user_transform_channels; + row_info->channels = png_ptr->user_transform_channels; #endif - png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth * - png_ptr->row_info.channels); + row_info->pixel_depth = (png_byte)(row_info->bit_depth * + row_info->channels); - png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth, - png_ptr->row_info.width); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width); } #endif - } #ifdef PNG_READ_PACK_SUPPORTED @@ -1761,105 +2476,128 @@ void /* PRIVATE */ png_do_unshift(png_row_infop row_info, png_bytep row, png_const_color_8p sig_bits) { + int color_type; + png_debug(1, "in png_do_unshift"); - if ( - row_info->color_type != PNG_COLOR_TYPE_PALETTE) + /* The palette case has already been handled in the _init routine. */ + color_type = row_info->color_type; + + if (color_type != PNG_COLOR_TYPE_PALETTE) { int shift[4]; int channels = 0; - int c; - png_uint_16 value = 0; - png_uint_32 row_width = row_info->width; + int bit_depth = row_info->bit_depth; - if (row_info->color_type & PNG_COLOR_MASK_COLOR) + if (color_type & PNG_COLOR_MASK_COLOR) { - shift[channels++] = row_info->bit_depth - sig_bits->red; - shift[channels++] = row_info->bit_depth - sig_bits->green; - shift[channels++] = row_info->bit_depth - sig_bits->blue; + shift[channels++] = bit_depth - sig_bits->red; + shift[channels++] = bit_depth - sig_bits->green; + shift[channels++] = bit_depth - sig_bits->blue; } else { - shift[channels++] = row_info->bit_depth - sig_bits->gray; + shift[channels++] = bit_depth - sig_bits->gray; } - if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + if (color_type & PNG_COLOR_MASK_ALPHA) { - shift[channels++] = row_info->bit_depth - sig_bits->alpha; + shift[channels++] = bit_depth - sig_bits->alpha; } - for (c = 0; c < channels; c++) { - if (shift[c] <= 0) - shift[c] = 0; + int c, have_shift; - else - value = 1; - } + for (c = have_shift = 0; c < channels; ++c) + { + /* A shift of more than the bit depth is an error condition but it + * gets ignored here. + */ + if (shift[c] <= 0 || shift[c] >= bit_depth) + shift[c] = 0; - if (!value) - return; + else + have_shift = 1; + } - switch (row_info->bit_depth) + if (!have_shift) + return; + } + + switch (bit_depth) { default: - break; + /* Must be 1bpp gray: should not be here! */ + /* NOTREACHED */ + break; case 2: + /* Must be 2bpp gray */ + /* assert(channels == 1 && shift[0] == 1) */ { - png_bytep bp; - png_size_t i; - png_size_t istop = row_info->rowbytes; + png_bytep bp = row; + png_bytep bp_end = bp + row_info->rowbytes; - for (bp = row, i = 0; i < istop; i++) + while (bp < bp_end) { - *bp >>= 1; - *bp++ &= 0x55; + int b = (*bp >> 1) & 0x55; + *bp++ = (png_byte)b; } break; } case 4: + /* Must be 4bpp gray */ + /* assert(channels == 1) */ { png_bytep bp = row; - png_size_t i; - png_size_t istop = row_info->rowbytes; - png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) | - (png_byte)((int)0xf >> shift[0])); + png_bytep bp_end = bp + row_info->rowbytes; + int gray_shift = shift[0]; + int mask = 0xf >> gray_shift; + + mask |= mask << 4; - for (i = 0; i < istop; i++) + while (bp < bp_end) { - *bp >>= shift[0]; - *bp++ &= mask; + int b = (*bp >> gray_shift) & mask; + *bp++ = (png_byte)b; } break; } case 8: + /* Single byte components, G, GA, RGB, RGBA */ { png_bytep bp = row; - png_uint_32 i; - png_uint_32 istop = row_width * channels; + png_bytep bp_end = bp + row_info->rowbytes; + int channel = 0; - for (i = 0; i < istop; i++) + while (bp < bp_end) { - *bp++ >>= shift[i%channels]; + int b = *bp >> shift[channel]; + if (++channel >= channels) + channel = 0; + *bp++ = (png_byte)b; } break; } #ifdef PNG_READ_16BIT_SUPPORTED case 16: + /* Double byte components, G, GA, RGB, RGBA */ { png_bytep bp = row; - png_uint_32 i; - png_uint_32 istop = channels * row_width; + png_bytep bp_end = bp + row_info->rowbytes; + int channel = 0; - for (i = 0; i < istop; i++) + while (bp < bp_end) { - value = (png_uint_16)((*bp << 8) + *(bp + 1)); - value >>= shift[i%channels]; + int value = (bp[0] << 8) + bp[1]; + + value >>= shift[channel]; + if (++channel >= channels) + channel = 0; *bp++ = (png_byte)(value >> 8); *bp++ = (png_byte)(value & 0xff); } @@ -1871,54 +2609,86 @@ png_do_unshift(png_row_infop row_info, png_bytep row, } #endif -#ifdef PNG_READ_16_TO_8_SUPPORTED -/* Chop rows of bit depth 16 down to 8 */ +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED +/* Scale rows of bit depth 16 down to 8 accurately */ void /* PRIVATE */ -png_do_chop(png_row_infop row_info, png_bytep row) +png_do_scale_16_to_8(png_row_infop row_info, png_bytep row) { - png_debug(1, "in png_do_chop"); + png_debug(1, "in png_do_scale_16_to_8"); if (row_info->bit_depth == 16) { - png_bytep sp = row; - png_bytep dp = row; - png_uint_32 i; - png_uint_32 istop = row_info->width * row_info->channels; + png_bytep sp = row; /* source */ + png_bytep dp = row; /* destination */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ - for (i = 0; i<istop; i++, sp += 2, dp++) + while (sp < ep) { -#ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED - /* This does a more accurate scaling of the 16-bit color - * value, rather than a simple low-byte truncation. - * - * What the ideal calculation should be: - * *dp = (((((png_uint_32)(*sp) << 8) | - * (png_uint_32)(*(sp + 1))) * 255 + 127) - * / (png_uint_32)65535L; - * - * GRR: no, I think this is what it really should be: - * *dp = (((((png_uint_32)(*sp) << 8) | - * (png_uint_32)(*(sp + 1))) + 128L) - * / (png_uint_32)257L; - * - * GRR: here's the exact calculation with shifts: - * temp = (((png_uint_32)(*sp) << 8) | - * (png_uint_32)(*(sp + 1))) + 128L; - * *dp = (temp - (temp >> 8)) >> 8; - * - * Approximate calculation with shift/add instead of multiply/divide: - * *dp = ((((png_uint_32)(*sp) << 8) | - * (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8; - * - * What we actually do to avoid extra shifting and conversion: - */ + /* The input is an array of 16 bit components, these must be scaled to + * 8 bits each. For a 16 bit value V the required value (from the PNG + * specification) is: + * + * (V * 255) / 65535 + * + * This reduces to round(V / 257), or floor((V + 128.5)/257) + * + * Represent V as the two byte value vhi.vlo. Make a guess that the + * result is the top byte of V, vhi, then the correction to this value + * is: + * + * error = floor(((V-vhi.vhi) + 128.5) / 257) + * = floor(((vlo-vhi) + 128.5) / 257) + * + * This can be approximated using integer arithmetic (and a signed + * shift): + * + * error = (vlo-vhi+128) >> 8; + * + * The approximate differs from the exact answer only when (vlo-vhi) is + * 128; it then gives a correction of +1 when the exact correction is + * 0. This gives 128 errors. The exact answer (correct for all 16 bit + * input values) is: + * + * error = (vlo-vhi+128)*65535 >> 24; + * + * An alternative arithmetic calculation which also gives no errors is: + * + * (V * 255 + 32895) >> 16 + */ - *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0); -#else - /* Simply discard the low order byte */ - *dp = *sp; + png_int_32 tmp = *sp++; /* must be signed! */ + tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24; + *dp++ = (png_byte)tmp; + } + + row_info->bit_depth = 8; + row_info->pixel_depth = (png_byte)(8 * row_info->channels); + row_info->rowbytes = row_info->width * row_info->channels; + } +} #endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED +void /* PRIVATE */ +/* Simply discard the low byte. This was the default behavior prior + * to libpng-1.5.4. + */ +png_do_chop(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_chop"); + + if (row_info->bit_depth == 16) + { + png_bytep sp = row; /* source */ + png_bytep dp = row; /* destination */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ + + while (sp < ep) + { + *dp++ = *sp; + sp += 2; /* skip low byte */ } + row_info->bit_depth = 8; row_info->pixel_depth = (png_byte)(8 * row_info->channels); row_info->rowbytes = row_info->width * row_info->channels; @@ -2390,7 +3160,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) } } } - row_info->channels += (png_byte)2; + row_info->channels = (png_byte)(row_info->channels + 2); row_info->color_type |= PNG_COLOR_MASK_COLOR; row_info->pixel_depth = (png_byte)(row_info->channels * row_info->bit_depth); @@ -2401,33 +3171,61 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED /* Reduce RGB files to grayscale, with or without alpha - * using the equation given in Poynton's ColorFAQ at - * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008) - * New link: - * <http://www.poynton.com/notes/colour_and_gamma/> + * using the equation given in Poynton's ColorFAQ of 1998-01-04 at + * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but + * versions dated 1998 through November 2002 have been archived at + * http://web.archive.org/web/20000816232553/http://www.inforamp.net/ + * ~poynton/notes/colour_and_gamma/ColorFAQ.txt ) * Charles Poynton poynton at poynton.com * * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B * - * We approximate this with + * which can be expressed with integers as + * + * Y = (6969 * R + 23434 * G + 2365 * B)/32768 * - * Y = 0.21268 * R + 0.7151 * G + 0.07217 * B + * Poynton's current link (as of January 2003 through July 2011): + * <http://www.poynton.com/notes/colour_and_gamma/> + * has changed the numbers slightly: + * + * Y = 0.2126*R + 0.7152*G + 0.0722*B * * which can be expressed with integers as * - * Y = (6969 * R + 23434 * G + 2365 * B)/32768 + * Y = (6966 * R + 23436 * G + 2366 * B)/32768 + * + * Historically, however, libpng uses numbers derived from the ITU-R Rec 709 + * end point chromaticities and the D65 white point. Depending on the + * precision used for the D65 white point this produces a variety of different + * numbers, however if the four decimal place value used in ITU-R Rec 709 is + * used (0.3127,0.3290) the Y calculation would be: + * + * Y = (6968 * R + 23435 * G + 2366 * B)/32768 + * + * While this is correct the rounding results in an overflow for white, because + * the sum of the rounded coefficients is 32769, not 32768. Consequently + * libpng uses, instead, the closest non-overflowing approximation: + * + * Y = (6968 * R + 23434 * G + 2366 * B)/32768 * - * The calculation is to be done in a linear colorspace. + * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk + * (including an sRGB chunk) then the chromaticities are used to calculate the + * coefficients. See the chunk handling in pngrutil.c for more information. * - * Other integer coefficents can be used via png_set_rgb_to_gray(). + * In all cases the calculation is to be done in a linear colorspace. If no + * gamma information is available to correct the encoding of the original RGB + * values this results in an implicit assumption that the original PNG RGB + * values were linear. + * + * Other integer coefficents can be used via png_set_rgb_to_gray(). Because + * the API takes just red and green coefficients the blue coefficient is + * calculated to make the sum 32768. This will result in different rounding + * to that used above. */ int /* PRIVATE */ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) { - png_uint_32 i; - - png_uint_32 row_width = row_info->width; int rgb_error = 0; png_debug(1, "in png_do_rgb_to_gray"); @@ -2435,235 +3233,180 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) && (row_info->color_type & PNG_COLOR_MASK_COLOR)) { - png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff; - png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff; - png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff; + PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff; + PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff; + PNG_CONST png_uint_32 bc = 32768 - rc - gc; + PNG_CONST png_uint_32 row_width = row_info->width; + PNG_CONST int have_alpha = + (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0; - if (row_info->color_type == PNG_COLOR_TYPE_RGB) + if (row_info->bit_depth == 8) { - if (row_info->bit_depth == 8) - { #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + /* Notice that gamma to/from 1 are not necessarily inverses (if + * there is an overall gamma correction). Prior to 1.5.5 this code + * checked the linearized values for equality; this doesn't match + * the documentation, the original values must be checked. + */ + if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) { - png_bytep sp = row; - png_bytep dp = row; + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); - for (i = 0; i < row_width; i++) + if (red != green || red != blue) { - png_byte red = png_ptr->gamma_to_1[*(sp++)]; - png_byte green = png_ptr->gamma_to_1[*(sp++)]; - png_byte blue = png_ptr->gamma_to_1[*(sp++)]; - - if (red != green || red != blue) - { - rgb_error |= 1; - *(dp++) = png_ptr->gamma_from_1[ - (rc*red + gc*green + bc*blue)>>15]; - } + red = png_ptr->gamma_to_1[red]; + green = png_ptr->gamma_to_1[green]; + blue = png_ptr->gamma_to_1[blue]; - else - *(dp++) = *(sp - 1); + rgb_error |= 1; + *(dp++) = png_ptr->gamma_from_1[ + (rc*red + gc*green + bc*blue + 16384)>>15]; } - } - else -#endif - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) - { - png_byte red = *(sp++); - png_byte green = *(sp++); - png_byte blue = *(sp++); - if (red != green || red != blue) - { - rgb_error |= 1; - *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15); - } + else + { + /* If there is no overall correction the table will not be + * set. + */ + if (png_ptr->gamma_table != NULL) + red = png_ptr->gamma_table[red]; - else - *(dp++) = *(sp - 1); + *(dp++) = red; } + + if (have_alpha) + *(dp++) = *(sp++); } } - - else /* RGB bit_depth == 16 */ + else +#endif { -#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_16_to_1 != NULL && - png_ptr->gamma_16_from_1 != NULL) - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) - { - png_uint_16 red, green, blue, w; - - red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - - if (red == green && red == blue) - w = red; - - else - { - png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) - >> png_ptr->gamma_shift][red>>8]; - png_uint_16 green_1 = - png_ptr->gamma_16_to_1[(green&0xff) >> - png_ptr->gamma_shift][green>>8]; - png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) - >> png_ptr->gamma_shift][blue>>8]; - png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1 - + bc*blue_1)>>15); - w = png_ptr->gamma_16_from_1[(gray16&0xff) >> - png_ptr->gamma_shift][gray16 >> 8]; - rgb_error |= 1; - } + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; - *(dp++) = (png_byte)((w>>8) & 0xff); - *(dp++) = (png_byte)(w & 0xff); - } - } - else -#endif + for (i = 0; i < row_width; i++) { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) - { - png_uint_16 red, green, blue, gray16; + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); - red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + if (red != green || red != blue) + { + rgb_error |= 1; + /*NOTE: this is the historical approach which simply + * truncates the results. + */ + *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15); + } - if (red != green || red != blue) - rgb_error |= 1; + else + *(dp++) = red; - gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15); - *(dp++) = (png_byte)((gray16>>8) & 0xff); - *(dp++) = (png_byte)(gray16 & 0xff); - } + if (have_alpha) + *(dp++) = *(sp++); } } } - if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + + else /* RGB bit_depth == 16 */ { - if (row_info->bit_depth == 8) - { #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) - { - png_byte red = png_ptr->gamma_to_1[*(sp++)]; - png_byte green = png_ptr->gamma_to_1[*(sp++)]; - png_byte blue = png_ptr->gamma_to_1[*(sp++)]; + png_uint_16 red, green, blue, w; - if (red != green || red != blue) - rgb_error |= 1; + red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - *(dp++) = png_ptr->gamma_from_1 - [(rc*red + gc*green + bc*blue)>>15]; + if (red == green && red == blue) + { + if (png_ptr->gamma_16_table != NULL) + w = png_ptr->gamma_16_table[(red&0xff) + >> png_ptr->gamma_shift][red>>8]; - *(dp++) = *(sp++); /* alpha */ + else + w = red; } - } - else -#endif - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) + + else + { + png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) + >> png_ptr->gamma_shift][red>>8]; + png_uint_16 green_1 = + png_ptr->gamma_16_to_1[(green&0xff) >> + png_ptr->gamma_shift][green>>8]; + png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) + >> png_ptr->gamma_shift][blue>>8]; + png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1 + + bc*blue_1 + 16384)>>15); + w = png_ptr->gamma_16_from_1[(gray16&0xff) >> + png_ptr->gamma_shift][gray16 >> 8]; + rgb_error |= 1; + } + + *(dp++) = (png_byte)((w>>8) & 0xff); + *(dp++) = (png_byte)(w & 0xff); + + if (have_alpha) { - png_byte red = *(sp++); - png_byte green = *(sp++); - png_byte blue = *(sp++); - if (red != green || red != blue) - rgb_error |= 1; - - *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15); - *(dp++) = *(sp++); /* alpha */ + *(dp++) = *(sp++); + *(dp++) = *(sp++); } } } - else /* RGBA bit_depth == 16 */ + else +#endif { -#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_16_to_1 != NULL && - png_ptr->gamma_16_from_1 != NULL) - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) - { - png_uint_16 red, green, blue, w; - - red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - - if (red == green && red == blue) - w = red; - - else - { - png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >> - png_ptr->gamma_shift][red>>8]; - - png_uint_16 green_1 = - png_ptr->gamma_16_to_1[(green&0xff) >> - png_ptr->gamma_shift][green>>8]; + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; - png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >> - png_ptr->gamma_shift][blue>>8]; + for (i = 0; i < row_width; i++) + { + png_uint_16 red, green, blue, gray16; - png_uint_16 gray16 = (png_uint_16)((rc * red_1 - + gc * green_1 + bc * blue_1)>>15); + red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; - w = png_ptr->gamma_16_from_1[(gray16&0xff) >> - png_ptr->gamma_shift][gray16 >> 8]; + if (red != green || red != blue) + rgb_error |= 1; - rgb_error |= 1; - } + /* From 1.5.5 in the 16 bit case do the accurate conversion even + * in the 'fast' case - this is because this is where the code + * ends up when handling linear 16 bit data. + */ + gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >> + 15); + *(dp++) = (png_byte)((gray16>>8) & 0xff); + *(dp++) = (png_byte)(gray16 & 0xff); - *(dp++) = (png_byte)((w>>8) & 0xff); - *(dp++) = (png_byte)(w & 0xff); - *(dp++) = *(sp++); /* alpha */ - *(dp++) = *(sp++); - } - } - else -#endif - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) + if (have_alpha) { - png_uint_16 red, green, blue, gray16; - red = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2; - green = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2; - blue = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2; - - if (red != green || red != blue) - rgb_error |= 1; - - gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15); - *(dp++) = (png_byte)((gray16>>8) & 0xff); - *(dp++) = (png_byte)(gray16 & 0xff); - *(dp++) = *(sp++); /* alpha */ + *(dp++) = *(sp++); *(dp++) = *(sp++); } } } } - row_info->channels -= 2; + + row_info->channels = (png_byte)(row_info->channels - 2); row_info->color_type = (png_byte)(row_info->color_type & ~PNG_COLOR_MASK_COLOR); row_info->pixel_depth = (png_byte)(row_info->channels * @@ -2673,11 +3416,13 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) return rgb_error; } #endif +#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ +#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED /* Build a grayscale palette. Palette is assumed to be 1 << bit_depth * large of png_color. This lets grayscale images be treated as * paletted. Most useful for gamma correction and simplification - * of code. + * of code. This API is not used internally. */ void PNGAPI png_build_grayscale_palette(int bit_depth, png_colorp palette) @@ -2727,34 +3472,37 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette) palette[i].blue = (png_byte)v; } } +#endif -#ifdef PNG_READ_BACKGROUND_SUPPORTED +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) /* Replace any alpha or transparency with the supplied background color. * "background" is already in the screen gamma, while "background_1" is * at a gamma of 1.0. Paletted files have already been taken care of. */ void /* PRIVATE */ -png_do_background(png_row_infop row_info, png_bytep row, - png_const_color_16p trans_color, png_const_color_16p background +png_do_compose(png_row_infop row_info, png_bytep row, png_structp png_ptr) +{ #ifdef PNG_READ_GAMMA_SUPPORTED - , png_const_color_16p background_1, png_const_bytep gamma_table, - png_const_bytep gamma_from_1, png_const_bytep gamma_to_1, - png_const_uint_16pp gamma_16, png_const_uint_16pp gamma_16_from_1, - png_const_uint_16pp gamma_16_to_1, int gamma_shift + png_const_bytep gamma_table = png_ptr->gamma_table; + png_const_bytep gamma_from_1 = png_ptr->gamma_from_1; + png_const_bytep gamma_to_1 = png_ptr->gamma_to_1; + png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table; + png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1; + png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1; + int gamma_shift = png_ptr->gamma_shift; #endif - ) -{ - png_bytep sp, dp; + + png_bytep sp; png_uint_32 i; png_uint_32 row_width = row_info->width; + int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0; int shift; - png_debug(1, "in png_do_background"); + png_debug(1, "in png_do_compose"); - if (background != NULL && - (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) || - (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_color))) { switch (row_info->color_type) { @@ -2769,10 +3517,10 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x01) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } if (!shift) @@ -2797,10 +3545,10 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x03) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } else @@ -2831,10 +3579,10 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x03) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } if (!shift) @@ -2860,10 +3608,10 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x0f) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } else @@ -2894,10 +3642,10 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x0f) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } if (!shift) @@ -2921,8 +3669,8 @@ png_do_background(png_row_infop row_info, png_bytep row, sp = row; for (i = 0; i < row_width; i++, sp++) { - if (*sp == trans_color->gray) - *sp = (png_byte)background->gray; + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; else *sp = gamma_table[*sp]; @@ -2934,8 +3682,8 @@ png_do_background(png_row_infop row_info, png_bytep row, sp = row; for (i = 0; i < row_width; i++, sp++) { - if (*sp == trans_color->gray) - *sp = (png_byte)background->gray; + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; } } break; @@ -2953,11 +3701,11 @@ png_do_background(png_row_infop row_info, png_bytep row, v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); - if (v == trans_color->gray) + if (v == png_ptr->trans_color.gray) { /* Background is already in screen gamma */ - *sp = (png_byte)((background->gray >> 8) & 0xff); - *(sp + 1) = (png_byte)(background->gray & 0xff); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } else @@ -2978,10 +3726,10 @@ png_do_background(png_row_infop row_info, png_bytep row, v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); - if (v == trans_color->gray) + if (v == png_ptr->trans_color.gray) { - *sp = (png_byte)((background->gray >> 8) & 0xff); - *(sp + 1) = (png_byte)(background->gray & 0xff); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } } } @@ -3004,13 +3752,13 @@ png_do_background(png_row_infop row_info, png_bytep row, sp = row; for (i = 0; i < row_width; i++, sp += 3) { - if (*sp == trans_color->red && - *(sp + 1) == trans_color->green && - *(sp + 2) == trans_color->blue) + if (*sp == png_ptr->trans_color.red && + *(sp + 1) == png_ptr->trans_color.green && + *(sp + 2) == png_ptr->trans_color.blue) { - *sp = (png_byte)background->red; - *(sp + 1) = (png_byte)background->green; - *(sp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } else @@ -3027,13 +3775,13 @@ png_do_background(png_row_infop row_info, png_bytep row, sp = row; for (i = 0; i < row_width; i++, sp += 3) { - if (*sp == trans_color->red && - *(sp + 1) == trans_color->green && - *(sp + 2) == trans_color->blue) + if (*sp == png_ptr->trans_color.red && + *(sp + 1) == png_ptr->trans_color.green && + *(sp + 2) == png_ptr->trans_color.blue) { - *sp = (png_byte)background->red; - *(sp + 1) = (png_byte)background->green; - *(sp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } } } @@ -3054,16 +3802,17 @@ png_do_background(png_row_infop row_info, png_bytep row, png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + *(sp + 5)); - if (r == trans_color->red && g == trans_color->green && - b == trans_color->blue) + if (r == png_ptr->trans_color.red && + g == png_ptr->trans_color.green && + b == png_ptr->trans_color.blue) { /* Background is already in screen gamma */ - *sp = (png_byte)((background->red >> 8) & 0xff); - *(sp + 1) = (png_byte)(background->red & 0xff); - *(sp + 2) = (png_byte)((background->green >> 8) & 0xff); - *(sp + 3) = (png_byte)(background->green & 0xff); - *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff); - *(sp + 5) = (png_byte)(background->blue & 0xff); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } else @@ -3097,15 +3846,16 @@ png_do_background(png_row_infop row_info, png_bytep row, png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + *(sp + 5)); - if (r == trans_color->red && g == trans_color->green && - b == trans_color->blue) + if (r == png_ptr->trans_color.red && + g == png_ptr->trans_color.green && + b == png_ptr->trans_color.blue) { - *sp = (png_byte)((background->red >> 8) & 0xff); - *(sp + 1) = (png_byte)(background->red & 0xff); - *(sp + 2) = (png_byte)((background->green >> 8) & 0xff); - *(sp + 3) = (png_byte)(background->green & 0xff); - *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff); - *(sp + 5) = (png_byte)(background->blue & 0xff); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } } } @@ -3122,18 +3872,17 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_table != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 2, dp++) + for (i = 0; i < row_width; i++, sp += 2) { png_uint_16 a = *(sp + 1); if (a == 0xff) - *dp = gamma_table[*sp]; + *sp = gamma_table[*sp]; else if (a == 0) { /* Background is already in screen gamma */ - *dp = (png_byte)background->gray; + *sp = (png_byte)png_ptr->background.gray; } else @@ -3141,8 +3890,10 @@ png_do_background(png_row_infop row_info, png_bytep row, png_byte v, w; v = gamma_to_1[*sp]; - png_composite(w, v, a, background_1->gray); - *dp = gamma_from_1[w]; + png_composite(w, v, a, png_ptr->background_1.gray); + if (!optimize) + w = gamma_from_1[w]; + *sp = w; } } } @@ -3150,24 +3901,15 @@ png_do_background(png_row_infop row_info, png_bytep row, #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 2, dp++) + for (i = 0; i < row_width; i++, sp += 2) { png_byte a = *(sp + 1); - if (a == 0xff) - *dp = *sp; - -#ifdef PNG_READ_GAMMA_SUPPORTED - else if (a == 0) - *dp = (png_byte)background->gray; - - else - png_composite(*dp, *sp, a, background_1->gray); + if (a == 0) + *sp = (png_byte)png_ptr->background.gray; -#else - *dp = (png_byte)background->gray; -#endif + else if (a < 0xff) + png_composite(*sp, *sp, a, png_ptr->background_1.gray); } } } @@ -3178,8 +3920,7 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_16_to_1 != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 2) + for (i = 0; i < row_width; i++, sp += 4) { png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8) + *(sp + 3)); @@ -3189,69 +3930,56 @@ png_do_background(png_row_infop row_info, png_bytep row, png_uint_16 v; v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; - *dp = (png_byte)((v >> 8) & 0xff); - *(dp + 1) = (png_byte)(v & 0xff); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); } -#ifdef PNG_READ_GAMMA_SUPPORTED else if (a == 0) -#else - else -#endif { /* Background is already in screen gamma */ - *dp = (png_byte)((background->gray >> 8) & 0xff); - *(dp + 1) = (png_byte)(background->gray & 0xff); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } -#ifdef PNG_READ_GAMMA_SUPPORTED else { png_uint_16 g, v, w; g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp]; - png_composite_16(v, g, a, background_1->gray); - w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8]; - *dp = (png_byte)((w >> 8) & 0xff); - *(dp + 1) = (png_byte)(w & 0xff); + png_composite_16(v, g, a, png_ptr->background_1.gray); + if (optimize) + w = v; + else + w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8]; + *sp = (png_byte)((w >> 8) & 0xff); + *(sp + 1) = (png_byte)(w & 0xff); } -#endif } } else #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 2) + for (i = 0; i < row_width; i++, sp += 4) { png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8) + *(sp + 3)); - if (a == (png_uint_16)0xffff) - png_memcpy(dp, sp, 2); - -#ifdef PNG_READ_GAMMA_SUPPORTED - else if (a == 0) -#else - else -#endif + if (a == 0) { - *dp = (png_byte)((background->gray >> 8) & 0xff); - *(dp + 1) = (png_byte)(background->gray & 0xff); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } -#ifdef PNG_READ_GAMMA_SUPPORTED - else + else if (a < 0xffff) { png_uint_16 g, v; g = (png_uint_16)(((*sp) << 8) + *(sp + 1)); - png_composite_16(v, g, a, background_1->gray); - *dp = (png_byte)((v >> 8) & 0xff); - *(dp + 1) = (png_byte)(v & 0xff); + png_composite_16(v, g, a, png_ptr->background_1.gray); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); } -#endif } } } @@ -3267,24 +3995,23 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_table != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 3) + for (i = 0; i < row_width; i++, sp += 4) { png_byte a = *(sp + 3); if (a == 0xff) { - *dp = gamma_table[*sp]; - *(dp + 1) = gamma_table[*(sp + 1)]; - *(dp + 2) = gamma_table[*(sp + 2)]; + *sp = gamma_table[*sp]; + *(sp + 1) = gamma_table[*(sp + 1)]; + *(sp + 2) = gamma_table[*(sp + 2)]; } else if (a == 0) { /* Background is already in screen gamma */ - *dp = (png_byte)background->red; - *(dp + 1) = (png_byte)background->green; - *(dp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } else @@ -3292,16 +4019,19 @@ png_do_background(png_row_infop row_info, png_bytep row, png_byte v, w; v = gamma_to_1[*sp]; - png_composite(w, v, a, background_1->red); - *dp = gamma_from_1[w]; + png_composite(w, v, a, png_ptr->background_1.red); + if (!optimize) w = gamma_from_1[w]; + *sp = w; v = gamma_to_1[*(sp + 1)]; - png_composite(w, v, a, background_1->green); - *(dp + 1) = gamma_from_1[w]; + png_composite(w, v, a, png_ptr->background_1.green); + if (!optimize) w = gamma_from_1[w]; + *(sp + 1) = w; v = gamma_to_1[*(sp + 2)]; - png_composite(w, v, a, background_1->blue); - *(dp + 2) = gamma_from_1[w]; + png_composite(w, v, a, png_ptr->background_1.blue); + if (!optimize) w = gamma_from_1[w]; + *(sp + 2) = w; } } } @@ -3309,34 +4039,26 @@ png_do_background(png_row_infop row_info, png_bytep row, #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 3) + for (i = 0; i < row_width; i++, sp += 4) { png_byte a = *(sp + 3); - if (a == 0xff) - { - *dp = *sp; - *(dp + 1) = *(sp + 1); - *(dp + 2) = *(sp + 2); - } - - else if (a == 0) + if (a == 0) { - *dp = (png_byte)background->red; - *(dp + 1) = (png_byte)background->green; - *(dp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } - else + else if (a < 0xff) { - png_composite(*dp, *sp, a, background->red); + png_composite(*sp, *sp, a, png_ptr->background.red); - png_composite(*(dp + 1), *(sp + 1), a, - background->green); + png_composite(*(sp + 1), *(sp + 1), a, + png_ptr->background.green); - png_composite(*(dp + 2), *(sp + 2), a, - background->blue); + png_composite(*(sp + 2), *(sp + 2), a, + png_ptr->background.blue); } } } @@ -3348,8 +4070,7 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_16_to_1 != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 8, dp += 6) + for (i = 0; i < row_width; i++, sp += 8) { png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) << 8) + (png_uint_16)(*(sp + 7))); @@ -3359,53 +4080,55 @@ png_do_background(png_row_infop row_info, png_bytep row, png_uint_16 v; v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; - *dp = (png_byte)((v >> 8) & 0xff); - *(dp + 1) = (png_byte)(v & 0xff); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)]; - *(dp + 2) = (png_byte)((v >> 8) & 0xff); - *(dp + 3) = (png_byte)(v & 0xff); + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 3) = (png_byte)(v & 0xff); v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)]; - *(dp + 4) = (png_byte)((v >> 8) & 0xff); - *(dp + 5) = (png_byte)(v & 0xff); + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 5) = (png_byte)(v & 0xff); } else if (a == 0) { /* Background is already in screen gamma */ - *dp = (png_byte)((background->red >> 8) & 0xff); - *(dp + 1) = (png_byte)(background->red & 0xff); - *(dp + 2) = (png_byte)((background->green >> 8) & 0xff); - *(dp + 3) = (png_byte)(background->green & 0xff); - *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff); - *(dp + 5) = (png_byte)(background->blue & 0xff); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } else { - png_uint_16 v, w, x; + png_uint_16 v, w; v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp]; - png_composite_16(w, v, a, background_1->red); - - x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; - *dp = (png_byte)((x >> 8) & 0xff); - *(dp + 1) = (png_byte)(x & 0xff); + png_composite_16(w, v, a, png_ptr->background_1.red); + if (!optimize) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; + *sp = (png_byte)((w >> 8) & 0xff); + *(sp + 1) = (png_byte)(w & 0xff); v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)]; - png_composite_16(w, v, a, background_1->green); + png_composite_16(w, v, a, png_ptr->background_1.green); + if (!optimize) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; - x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; - *(dp + 2) = (png_byte)((x >> 8) & 0xff); - *(dp + 3) = (png_byte)(x & 0xff); + *(sp + 2) = (png_byte)((w >> 8) & 0xff); + *(sp + 3) = (png_byte)(w & 0xff); v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)]; - png_composite_16(w, v, a, background_1->blue); + png_composite_16(w, v, a, png_ptr->background_1.blue); + if (!optimize) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; - x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8]; - *(dp + 4) = (png_byte)((x >> 8) & 0xff); - *(dp + 5) = (png_byte)(x & 0xff); + *(sp + 4) = (png_byte)((w >> 8) & 0xff); + *(sp + 5) = (png_byte)(w & 0xff); } } } @@ -3414,28 +4137,22 @@ png_do_background(png_row_infop row_info, png_bytep row, #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 8, dp += 6) + for (i = 0; i < row_width; i++, sp += 8) { png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) << 8) + (png_uint_16)(*(sp + 7))); - if (a == (png_uint_16)0xffff) - { - png_memcpy(dp, sp, 6); - } - - else if (a == 0) + if (a == 0) { - *dp = (png_byte)((background->red >> 8) & 0xff); - *(dp + 1) = (png_byte)(background->red & 0xff); - *(dp + 2) = (png_byte)((background->green >> 8) & 0xff); - *(dp + 3) = (png_byte)(background->green & 0xff); - *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff); - *(dp + 5) = (png_byte)(background->blue & 0xff); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } - else + else if (a < 0xffff) { png_uint_16 v; @@ -3445,17 +4162,17 @@ png_do_background(png_row_infop row_info, png_bytep row, png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + *(sp + 5)); - png_composite_16(v, r, a, background->red); - *dp = (png_byte)((v >> 8) & 0xff); - *(dp + 1) = (png_byte)(v & 0xff); + png_composite_16(v, r, a, png_ptr->background.red); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); - png_composite_16(v, g, a, background->green); - *(dp + 2) = (png_byte)((v >> 8) & 0xff); - *(dp + 3) = (png_byte)(v & 0xff); + png_composite_16(v, g, a, png_ptr->background.green); + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 3) = (png_byte)(v & 0xff); - png_composite_16(v, b, a, background->blue); - *(dp + 4) = (png_byte)((v >> 8) & 0xff); - *(dp + 5) = (png_byte)(v & 0xff); + png_composite_16(v, b, a, png_ptr->background.blue); + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 5) = (png_byte)(v & 0xff); } } } @@ -3466,19 +4183,9 @@ png_do_background(png_row_infop row_info, png_bytep row, default: break; } - - if (row_info->color_type & PNG_COLOR_MASK_ALPHA) - { - row_info->color_type = (png_byte)(row_info->color_type & - ~PNG_COLOR_MASK_ALPHA); - row_info->channels--; - row_info->pixel_depth = (png_byte)(row_info->channels * - row_info->bit_depth); - row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); - } } } -#endif +#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */ #ifdef PNG_READ_GAMMA_SUPPORTED /* Gamma correct the image, avoiding the alpha channel. Make sure @@ -3488,10 +4195,12 @@ png_do_background(png_row_infop row_info, png_bytep row, * build_gamma_table(). */ void /* PRIVATE */ -png_do_gamma(png_row_infop row_info, png_bytep row, - png_const_bytep gamma_table, png_const_uint_16pp gamma_16_table, - int gamma_shift) +png_do_gamma(png_row_infop row_info, png_bytep row, png_structp png_ptr) { + png_const_bytep gamma_table = png_ptr->gamma_table; + png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table; + int gamma_shift = png_ptr->gamma_shift; + png_bytep sp; png_uint_32 i; png_uint_32 row_width=row_info->width; @@ -3681,6 +4390,73 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } #endif +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED +/* Encode the alpha channel to the output gamma (the input channel is always + * linear.) Called only with color types that have an alpha channel. Needs the + * from_1 tables. + */ +void /* PRIVATE */ +png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structp png_ptr) +{ + png_uint_32 row_width = row_info->width; + + png_debug(1, "in png_do_encode_alpha"); + + if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + { + if (row_info->bit_depth == 8) + { + PNG_CONST png_bytep table = png_ptr->gamma_from_1; + + if (table != NULL) + { + PNG_CONST int step = + (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2; + + /* The alpha channel is the last component: */ + row += step - 1; + + for (; row_width > 0; --row_width, row += step) + *row = table[*row]; + + return; + } + } + + else if (row_info->bit_depth == 16) + { + PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1; + PNG_CONST int gamma_shift = png_ptr->gamma_shift; + + if (table != NULL) + { + PNG_CONST int step = + (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4; + + /* The alpha channel is the last component: */ + row += step - 2; + + for (; row_width > 0; --row_width, row += step) + { + png_uint_16 v; + + v = table[*(row + 1) >> gamma_shift][*row]; + *row = (png_byte)((v >> 8) & 0xff); + *(row + 1) = (png_byte)(v & 0xff); + } + + return; + } + } + } + + /* Only get to here if called with a weird row_info; no harm has been done, + * so just issue a warning. + */ + png_warning(png_ptr, "png_do_encode_alpha: unexpected call"); +} +#endif + #ifdef PNG_READ_EXPAND_SUPPORTED /* Expands a palette row to an RGB or RGBA row depending * upon whether you supply trans and num_trans. @@ -3786,7 +4562,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, if (row_info->bit_depth == 8) { { - if (trans_alpha != NULL) + if (num_trans > 0) { sp = row + (png_size_t)row_width - 1; dp = row + (png_size_t)(row_width << 2) - 1; @@ -3840,7 +4616,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, */ void /* PRIVATE */ png_do_expand(png_row_infop row_info, png_bytep row, - png_const_color_16p trans_value) + png_const_color_16p trans_color) { int shift, value; png_bytep sp, dp; @@ -3852,7 +4628,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, { if (row_info->color_type == PNG_COLOR_TYPE_GRAY) { - png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0); + png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0); if (row_info->bit_depth < 8) { @@ -3944,7 +4720,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width; } - if (trans_value != NULL) + if (trans_color != NULL) { if (row_info->bit_depth == 8) { @@ -3996,13 +4772,13 @@ png_do_expand(png_row_infop row_info, png_bytep row, row_width); } } - else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value) + else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color) { if (row_info->bit_depth == 8) { - png_byte red = (png_byte)(trans_value->red & 0xff); - png_byte green = (png_byte)(trans_value->green & 0xff); - png_byte blue = (png_byte)(trans_value->blue & 0xff); + png_byte red = (png_byte)(trans_color->red & 0xff); + png_byte green = (png_byte)(trans_color->green & 0xff); + png_byte blue = (png_byte)(trans_color->blue & 0xff); sp = row + (png_size_t)row_info->rowbytes - 1; dp = row + (png_size_t)(row_width << 2) - 1; for (i = 0; i < row_width; i++) @@ -4020,12 +4796,12 @@ png_do_expand(png_row_infop row_info, png_bytep row, } else if (row_info->bit_depth == 16) { - png_byte red_high = (png_byte)((trans_value->red >> 8) & 0xff); - png_byte green_high = (png_byte)((trans_value->green >> 8) & 0xff); - png_byte blue_high = (png_byte)((trans_value->blue >> 8) & 0xff); - png_byte red_low = (png_byte)(trans_value->red & 0xff); - png_byte green_low = (png_byte)(trans_value->green & 0xff); - png_byte blue_low = (png_byte)(trans_value->blue & 0xff); + png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff); + png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff); + png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff); + png_byte red_low = (png_byte)(trans_color->red & 0xff); + png_byte green_low = (png_byte)(trans_color->green & 0xff); + png_byte blue_low = (png_byte)(trans_color->blue & 0xff); sp = row + row_info->rowbytes - 1; dp = row + (png_size_t)(row_width << 3) - 1; for (i = 0; i < row_width; i++) @@ -4064,6 +4840,37 @@ png_do_expand(png_row_infop row_info, png_bytep row, } #endif +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* If the bit depth is 8 and the color type is not a palette type expand the + * whole row to 16 bits. Has no effect otherwise. + */ +void /* PRIVATE */ +png_do_expand_16(png_row_infop row_info, png_bytep row) +{ + if (row_info->bit_depth == 8 && + row_info->color_type != PNG_COLOR_TYPE_PALETTE) + { + /* The row have a sequence of bytes containing [0..255] and we need + * to turn it into another row containing [0..65535], to do this we + * calculate: + * + * (input / 255) * 65535 + * + * Which happens to be exactly input * 257 and this can be achieved + * simply by byte replication in place (copying backwards). + */ + png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */ + png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */ + while (dp > sp) + dp[-2] = dp[-1] = *--sp, dp -= 2; + + row_info->rowbytes *= 2; + row_info->bit_depth = 16; + row_info->pixel_depth = (png_byte)(row_info->channels * 16); + } +} +#endif + #ifdef PNG_READ_QUANTIZE_SUPPORTED void /* PRIVATE */ png_do_quantize(png_row_infop row_info, png_bytep row, @@ -4157,6 +4964,7 @@ png_do_quantize(png_row_infop row_info, png_bytep row, } } #endif /* PNG_READ_QUANTIZE_SUPPORTED */ +#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ #ifdef PNG_MNG_FEATURES_SUPPORTED /* Undoes intrapixel differencing */ @@ -4210,8 +5018,8 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1); png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3); png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5); - png_uint_32 red = (png_uint_32)((s0 + s1 + 65536L) & 0xffffL); - png_uint_32 blue = (png_uint_32)((s2 + s1 + 65536L) & 0xffffL); + png_uint_32 red = (s0 + s1 + 65536) & 0xffff; + png_uint_32 blue = (s2 + s1 + 65536) & 0xffff; *(rp ) = (png_byte)((red >> 8) & 0xff); *(rp + 1) = (png_byte)(red & 0xff); *(rp + 4) = (png_byte)((blue >> 8) & 0xff); |