diff options
Diffstat (limited to 'src/3rdparty/freetype/src/autofit/afhints.h')
-rw-r--r-- | src/3rdparty/freetype/src/autofit/afhints.h | 288 |
1 files changed, 209 insertions, 79 deletions
diff --git a/src/3rdparty/freetype/src/autofit/afhints.h b/src/3rdparty/freetype/src/autofit/afhints.h index 675826835a..92101de7ca 100644 --- a/src/3rdparty/freetype/src/autofit/afhints.h +++ b/src/3rdparty/freetype/src/autofit/afhints.h @@ -4,7 +4,7 @@ /* */ /* Auto-fitter hinting routines (specification). */ /* */ -/* Copyright 2003, 2004, 2005, 2006, 2007, 2008 by */ +/* Copyright 2003-2008, 2010-2012, 2014 by */ /* David Turner, Robert Wilhelm, and Werner Lemberg. */ /* */ /* This file is part of the FreeType project, and may only be used, */ @@ -25,10 +25,10 @@ FT_BEGIN_HEADER - /* - * The definition of outline glyph hints. These are shared by all - * script analysis routines (until now). - */ + /* + * The definition of outline glyph hints. These are shared by all + * writing system analysis routines (until now). + */ typedef enum AF_Dimension_ { @@ -55,6 +55,157 @@ FT_BEGIN_HEADER } AF_Direction; + /* + * The following explanations are mostly taken from the article + * + * Real-Time Grid Fitting of Typographic Outlines + * + * by David Turner and Werner Lemberg + * + * http://www.tug.org/TUGboat/Articles/tb24-3/lemberg.pdf + * + * with appropriate updates. + * + * + * Segments + * + * `af_{cjk,latin,...}_hints_compute_segments' are the functions to + * find segments in an outline. + * + * A segment is a series of at least two consecutive points that are + * approximately aligned along a coordinate axis. The analysis to do + * so is specific to a writing system. + * + * + * Edges + * + * `af_{cjk,latin,...}_hints_compute_edges' are the functions to find + * edges. + * + * As soon as segments are defined, the auto-hinter groups them into + * edges. An edge corresponds to a single position on the main + * dimension that collects one or more segments (allowing for a small + * threshold). + * + * As an example, the `latin' writing system first tries to grid-fit + * edges, then to align segments on the edges unless it detects that + * they form a serif. + * + * + * A H + * | | + * | | + * | | + * | | + * C | | F + * +------<-----+ +-----<------+ + * | B G | + * | | + * | | + * +--------------->------------------+ + * D E + * + * + * Stems + * + * Stems are detected by `af_{cjk,latin,...}_hint_edges'. + * + * Segments need to be `linked' to other ones in order to detect stems. + * A stem is made of two segments that face each other in opposite + * directions and that are sufficiently close to each other. Using + * vocabulary from the TrueType specification, stem segments form a + * `black distance'. + * + * In the above ASCII drawing, the horizontal segments are BC, DE, and + * FG; the vertical segments are AB, CD, EF, and GH. + * + * Each segment has at most one `best' candidate to form a black + * distance, or no candidate at all. Notice that two distinct segments + * can have the same candidate, which frequently means a serif. + * + * A stem is recognized by the following condition: + * + * best segment_1 = segment_2 && best segment_2 = segment_1 + * + * The best candidate is stored in field `link' in structure + * `AF_Segment'. + * + * In the above ASCII drawing, the best candidate for both AB and CD is + * GH, while the best candidate for GH is AB. Similarly, the best + * candidate for EF and GH is AB, while the best candidate for AB is + * GH. + * + * The detection and handling of stems is dependent on the writing + * system. + * + * + * Serifs + * + * Serifs are detected by `af_{cjk,latin,...}_hint_edges'. + * + * In comparison to a stem, a serif (as handled by the auto-hinter + * module that takes care of the `latin' writing system) has + * + * best segment_1 = segment_2 && best segment_2 != segment_1 + * + * where segment_1 corresponds to the serif segment (CD and EF in the + * above ASCII drawing). + * + * The best candidate is stored in field `serif' in structure + * `AF_Segment' (and `link' is set to NULL). + * + * + * Touched points + * + * A point is called `touched' if it has been processed somehow by the + * auto-hinter. It basically means that it shouldn't be moved again + * (or moved only under certain constraints to preserve the already + * applied processing). + * + * + * Flat and round segments + * + * Segments are `round' or `flat', depending on the series of points + * that define them. A segment is round if the next and previous point + * of an extremum (which can be either a single point or sequence of + * points) are both conic or cubic control points. Otherwise, a + * segment with an extremum is flat. + * + * + * Strong Points + * + * Experience has shown that points not part of an edge need to be + * interpolated linearly between their two closest edges, even if these + * are not part of the contour of those particular points. Typical + * candidates for this are + * + * - angle points (i.e., points where the `in' and `out' direction + * differ greatly) + * + * - inflection points (i.e., where the `in' and `out' angles are the + * same, but the curvature changes sign) [currently, such points + * aren't handled specially in the auto-hinter] + * + * `af_glyph_hints_align_strong_points' is the function that takes + * care of such situations; it is equivalent to the TrueType `IP' + * hinting instruction. + * + * + * Weak Points + * + * Other points in the outline must be interpolated using the + * coordinates of their previous and next unfitted contour neighbours. + * These are called `weak points' and are touched by the function + * `af_glyph_hints_align_weak_points', equivalent to the TrueType `IUP' + * hinting instruction. Typical candidates are control points and + * points on the contour without a major direction. + * + * The major effect is to reduce possible distortion caused by + * alignment of edges and strong points, thus weak points are processed + * after strong points. + */ + + /* point hint flags */ typedef enum AF_Flags_ { @@ -65,23 +216,12 @@ FT_BEGIN_HEADER AF_FLAG_CUBIC = 1 << 1, AF_FLAG_CONTROL = AF_FLAG_CONIC | AF_FLAG_CUBIC, - /* point extremum flags */ - AF_FLAG_EXTREMA_X = 1 << 2, - AF_FLAG_EXTREMA_Y = 1 << 3, - - /* point roundness flags */ - AF_FLAG_ROUND_X = 1 << 4, - AF_FLAG_ROUND_Y = 1 << 5, - /* point touch flags */ - AF_FLAG_TOUCH_X = 1 << 6, - AF_FLAG_TOUCH_Y = 1 << 7, + AF_FLAG_TOUCH_X = 1 << 2, + AF_FLAG_TOUCH_Y = 1 << 3, /* candidates for weak interpolation have this flag set */ - AF_FLAG_WEAK_INTERPOLATION = 1 << 8, - - /* all inflection points in the outline have this flag set */ - AF_FLAG_INFLECTION = 1 << 9 + AF_FLAG_WEAK_INTERPOLATION = 1 << 4 } AF_Flags; @@ -89,10 +229,11 @@ FT_BEGIN_HEADER /* edge hint flags */ typedef enum AF_Edge_Flags_ { - AF_EDGE_NORMAL = 0, - AF_EDGE_ROUND = 1 << 0, - AF_EDGE_SERIF = 1 << 1, - AF_EDGE_DONE = 1 << 2 + AF_EDGE_NORMAL = 0, + AF_EDGE_ROUND = 1 << 0, + AF_EDGE_SERIF = 1 << 1, + AF_EDGE_DONE = 1 << 2, + AF_EDGE_NEUTRAL = 1 << 3 /* set if edge aligns to a neutral blue zone */ } AF_Edge_Flags; @@ -109,7 +250,7 @@ FT_BEGIN_HEADER FT_Char out_dir; /* direction of outwards vector */ FT_Pos ox, oy; /* original, scaled position */ - FT_Short fx, fy; /* original, unscaled position (font units) */ + FT_Short fx, fy; /* original, unscaled position (in font units) */ FT_Pos x, y; /* current position */ FT_Pos u, v; /* current (x,y) or (y,x) depending on context */ @@ -137,84 +278,80 @@ FT_BEGIN_HEADER FT_Pos score; /* used during stem matching */ FT_Pos len; /* used during stem matching */ - AF_Point first; /* first point in edge segment */ - AF_Point last; /* last point in edge segment */ - AF_Point* contour; /* ptr to first point of segment's contour */ + AF_Point first; /* first point in edge segment */ + AF_Point last; /* last point in edge segment */ } AF_SegmentRec; typedef struct AF_EdgeRec_ { - FT_Short fpos; /* original, unscaled position (font units) */ - FT_Pos opos; /* original, scaled position */ - FT_Pos pos; /* current position */ + FT_Short fpos; /* original, unscaled position (in font units) */ + FT_Pos opos; /* original, scaled position */ + FT_Pos pos; /* current position */ FT_Byte flags; /* edge flags */ FT_Char dir; /* edge direction */ FT_Fixed scale; /* used to speed up interpolation between edges */ - AF_Width blue_edge; /* non-NULL if this is a blue edge */ - AF_Edge link; - AF_Edge serif; - FT_Short num_linked; + AF_Width blue_edge; /* non-NULL if this is a blue edge */ + AF_Edge link; /* link edge */ + AF_Edge serif; /* primary edge for serifs */ + FT_Short num_linked; /* number of linked edges */ + FT_Int score; /* used during stem matching */ - FT_Int score; - - AF_Segment first; - AF_Segment last; + AF_Segment first; /* first segment in edge */ + AF_Segment last; /* last segment in edge */ } AF_EdgeRec; typedef struct AF_AxisHintsRec_ { - FT_Int num_segments; - FT_Int max_segments; - AF_Segment segments; + FT_Int num_segments; /* number of used segments */ + FT_Int max_segments; /* number of allocated segments */ + AF_Segment segments; /* segments array */ #ifdef AF_SORT_SEGMENTS FT_Int mid_segments; #endif - FT_Int num_edges; - FT_Int max_edges; - AF_Edge edges; + FT_Int num_edges; /* number of used edges */ + FT_Int max_edges; /* number of allocated edges */ + AF_Edge edges; /* edges array */ - AF_Direction major_dir; + AF_Direction major_dir; /* either vertical or horizontal */ } AF_AxisHintsRec, *AF_AxisHints; typedef struct AF_GlyphHintsRec_ { - FT_Memory memory; + FT_Memory memory; - FT_Fixed x_scale; - FT_Pos x_delta; + FT_Fixed x_scale; + FT_Pos x_delta; - FT_Fixed y_scale; - FT_Pos y_delta; + FT_Fixed y_scale; + FT_Pos y_delta; - FT_Pos edge_distance_threshold; + FT_Int max_points; /* number of allocated points */ + FT_Int num_points; /* number of used points */ + AF_Point points; /* points array */ - FT_Int max_points; - FT_Int num_points; - AF_Point points; + FT_Int max_contours; /* number of allocated contours */ + FT_Int num_contours; /* number of used contours */ + AF_Point* contours; /* contours array */ - FT_Int max_contours; - FT_Int num_contours; - AF_Point* contours; + AF_AxisHintsRec axis[AF_DIMENSION_MAX]; - AF_AxisHintsRec axis[AF_DIMENSION_MAX]; + FT_UInt32 scaler_flags; /* copy of scaler flags */ + FT_UInt32 other_flags; /* free for style-specific */ + /* implementations */ + AF_StyleMetrics metrics; - FT_UInt32 scaler_flags; /* copy of scaler flags */ - FT_UInt32 other_flags; /* free for script-specific */ - /* implementations */ - AF_ScriptMetrics metrics; + FT_Pos xmin_delta; /* used for warping */ + FT_Pos xmax_delta; - FT_Pos xmin_delta; /* used for warping */ - FT_Pos xmax_delta; - } AF_GlyphHintsRec; @@ -222,7 +359,7 @@ FT_BEGIN_HEADER #define AF_HINTS_TEST_OTHER( h, f ) ( (h)->other_flags & (f) ) -#ifdef AF_DEBUG +#ifdef FT_DEBUG_AUTOFIT #define AF_HINTS_DO_HORIZONTAL( h ) \ ( !_af_debug_disable_horz_hints && \ @@ -237,7 +374,7 @@ FT_BEGIN_HEADER #define AF_HINTS_DO_BLUES( h ) ( !_af_debug_disable_blue_hints ) -#else /* !AF_DEBUG */ +#else /* !FT_DEBUG_AUTOFIT */ #define AF_HINTS_DO_HORIZONTAL( h ) \ !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_HORIZONTAL ) @@ -250,7 +387,7 @@ FT_BEGIN_HEADER #define AF_HINTS_DO_BLUES( h ) 1 -#endif /* !AF_DEBUG */ +#endif /* !FT_DEBUG_AUTOFIT */ FT_LOCAL( AF_Direction ) @@ -274,20 +411,13 @@ FT_BEGIN_HEADER af_glyph_hints_init( AF_GlyphHints hints, FT_Memory memory ); - - - /* - * recompute all AF_Point in a AF_GlyphHints from the definitions - * in a source outline - */ FT_LOCAL( void ) - af_glyph_hints_rescale( AF_GlyphHints hints, - AF_ScriptMetrics metrics ); + af_glyph_hints_rescale( AF_GlyphHints hints, + AF_StyleMetrics metrics ); FT_LOCAL( FT_Error ) af_glyph_hints_reload( AF_GlyphHints hints, - FT_Outline* outline, - FT_Bool get_inflections ); + FT_Outline* outline ); FT_LOCAL( void ) af_glyph_hints_save( AF_GlyphHints hints, @@ -305,7 +435,7 @@ FT_BEGIN_HEADER af_glyph_hints_align_weak_points( AF_GlyphHints hints, AF_Dimension dim ); -#ifdef AF_USE_WARPER +#ifdef AF_CONFIG_OPTION_USE_WARPER FT_LOCAL( void ) af_glyph_hints_scale_dim( AF_GlyphHints hints, AF_Dimension dim, |