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kc3-lang/freetype/src/autofit/afhints.h
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Author :
Werner Lemberg
Date : 2011-03-02 03:52:36
Hash : 576fc2c0
Message : Add AF_CONFIG_OPTION_USE_WARPER to control the autofit warper. * devel/ftoption.h, include/freetype/config/ftoption.h (AF_CONFIG_OPTION_USE_WARPER): New macro. * src/autofit/aftypes.h (AF_USE_WARPER): Remove. * src/autofit/*: s/AF_USE_WARPER/AF_CONFIG_OPTION_USE_WARPER/. * src/autofit/afwarp.c [!AF_CONFIG_OPTION_USE_WARPER]: Replace dummy variable assignment with a typedef.
- src/autofit/afhints.h
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/***************************************************************************/ /* */ /* afhints.h */ /* */ /* Auto-fitter hinting routines (specification). */ /* */ /* Copyright 2003-2008, 2010-2011 by */ /* David Turner, Robert Wilhelm, and Werner Lemberg. */ /* */ /* This file is part of the FreeType project, and may only be used, */ /* modified, and distributed under the terms of the FreeType project */ /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ /* this file you indicate that you have read the license and */ /* understand and accept it fully. */ /* */ /***************************************************************************/ #ifndef __AFHINTS_H__ #define __AFHINTS_H__ #include "aftypes.h" #define xxAF_SORT_SEGMENTS FT_BEGIN_HEADER /* * The definition of outline glyph hints. These are shared by all * script analysis routines (until now). */ typedef enum AF_Dimension_ { AF_DIMENSION_HORZ = 0, /* x coordinates, */ /* i.e., vertical segments & edges */ AF_DIMENSION_VERT = 1, /* y coordinates, */ /* i.e., horizontal segments & edges */ AF_DIMENSION_MAX /* do not remove */ } AF_Dimension; /* hint directions -- the values are computed so that two vectors are */ /* in opposite directions iff `dir1 + dir2 == 0' */ typedef enum AF_Direction_ { AF_DIR_NONE = 4, AF_DIR_RIGHT = 1, AF_DIR_LEFT = -1, AF_DIR_UP = 2, AF_DIR_DOWN = -2 } 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 * * * Segments * * `af_{cjk,latin,...}_hints_compute_segments' are the functions to * find segments in an outline. A segment is a series of consecutive * points that are approximately aligned along a coordinate axis. The * analysis to do so is specific to a script. * * A segment must have at least two points, except in the case of * `fake' segments that are generated to hint metrics appropriately, * and which consist of a single point. * * * 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). * * The auto-hinter first tries to grid fit edges, then to align * segments on the edges unless it detects that they form a serif. * * `af_{cjk,latin,...}_hints_compute_edges' are the functions to find * edges; they are specific to a script. * * * A H * | | * | | * | | * | | * C | | F * +------<-----+ +-----<------+ * | B G | * | | * | | * +--------------->------------------+ * D E * * * Stems * * 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'. * * Stems are detected by `af_{cjk,latin,...}_hint_edges'. * * 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. * * * Serifs * * On the opposite, a serif 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). * * Serifs are detected by `af_{cjk,latin,...}_hint_edges'. * * * 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 which are 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) * * `af_glyph_hints_align_strong_points' is the function which 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_ { AF_FLAG_NONE = 0, /* point type flags */ AF_FLAG_CONIC = 1 << 0, 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, /* 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_Flags; /* 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_Flags; typedef struct AF_PointRec_* AF_Point; typedef struct AF_SegmentRec_* AF_Segment; typedef struct AF_EdgeRec_* AF_Edge; typedef struct AF_PointRec_ { FT_UShort flags; /* point flags used by hinter */ FT_Char in_dir; /* direction of inwards vector */ 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_Pos x, y; /* current position */ FT_Pos u, v; /* current (x,y) or (y,x) depending on context */ AF_Point next; /* next point in contour */ AF_Point prev; /* previous point in contour */ } AF_PointRec; typedef struct AF_SegmentRec_ { FT_Byte flags; /* edge/segment flags for this segment */ FT_Char dir; /* segment direction */ FT_Short pos; /* position of segment */ FT_Short min_coord; /* minimum coordinate of segment */ FT_Short max_coord; /* maximum coordinate of segment */ FT_Short height; /* the hinted segment height */ AF_Edge edge; /* the segment's parent edge */ AF_Segment edge_next; /* link to next segment in parent edge */ AF_Segment link; /* (stem) link segment */ AF_Segment serif; /* primary segment for serifs */ FT_Pos num_linked; /* number of linked segments */ 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_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_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; /* link edge */ AF_Edge serif; /* primary edge for serifs */ FT_Short num_linked; /* number of linked edges */ FT_Int score; /* used during stem matching */ AF_Segment first; /* first segment in edge */ AF_Segment last; /* last segment in edge */ } AF_EdgeRec; typedef struct AF_AxisHintsRec_ { 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; /* number of used edges */ FT_Int max_edges; /* number of allocated edges */ AF_Edge edges; /* edges array */ AF_Direction major_dir; /* either vertical or horizontal */ } AF_AxisHintsRec, *AF_AxisHints; typedef struct AF_GlyphHintsRec_ { FT_Memory memory; FT_Fixed x_scale; FT_Pos x_delta; FT_Fixed y_scale; FT_Pos y_delta; FT_Int max_points; /* number of allocated points */ FT_Int num_points; /* number of used points */ AF_Point points; /* points array */ FT_Int max_contours; /* number of allocated contours */ FT_Int num_contours; /* number of used contours */ AF_Point* contours; /* contours array */ AF_AxisHintsRec axis[AF_DIMENSION_MAX]; 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; } AF_GlyphHintsRec; #define AF_HINTS_TEST_SCALER( h, f ) ( (h)->scaler_flags & (f) ) #define AF_HINTS_TEST_OTHER( h, f ) ( (h)->other_flags & (f) ) #ifdef AF_DEBUG #define AF_HINTS_DO_HORIZONTAL( h ) \ ( !_af_debug_disable_horz_hints && \ !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_HORIZONTAL ) ) #define AF_HINTS_DO_VERTICAL( h ) \ ( !_af_debug_disable_vert_hints && \ !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_VERTICAL ) ) #define AF_HINTS_DO_ADVANCE( h ) \ !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_ADVANCE ) #define AF_HINTS_DO_BLUES( h ) ( !_af_debug_disable_blue_hints ) #else /* !AF_DEBUG */ #define AF_HINTS_DO_HORIZONTAL( h ) \ !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_HORIZONTAL ) #define AF_HINTS_DO_VERTICAL( h ) \ !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_VERTICAL ) #define AF_HINTS_DO_ADVANCE( h ) \ !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_ADVANCE ) #define AF_HINTS_DO_BLUES( h ) 1 #endif /* !AF_DEBUG */ FT_LOCAL( AF_Direction ) af_direction_compute( FT_Pos dx, FT_Pos dy ); FT_LOCAL( FT_Error ) af_axis_hints_new_segment( AF_AxisHints axis, FT_Memory memory, AF_Segment *asegment ); FT_LOCAL( FT_Error) af_axis_hints_new_edge( AF_AxisHints axis, FT_Int fpos, AF_Direction dir, FT_Memory memory, AF_Edge *edge ); FT_LOCAL( void ) af_glyph_hints_init( AF_GlyphHints hints, FT_Memory memory ); FT_LOCAL( void ) af_glyph_hints_rescale( AF_GlyphHints hints, AF_ScriptMetrics metrics ); FT_LOCAL( FT_Error ) af_glyph_hints_reload( AF_GlyphHints hints, FT_Outline* outline ); FT_LOCAL( void ) af_glyph_hints_save( AF_GlyphHints hints, FT_Outline* outline ); FT_LOCAL( void ) af_glyph_hints_align_edge_points( AF_GlyphHints hints, AF_Dimension dim ); FT_LOCAL( void ) af_glyph_hints_align_strong_points( AF_GlyphHints hints, AF_Dimension dim ); FT_LOCAL( void ) af_glyph_hints_align_weak_points( AF_GlyphHints hints, AF_Dimension dim ); #ifdef AF_CONFIG_OPTION_USE_WARPER FT_LOCAL( void ) af_glyph_hints_scale_dim( AF_GlyphHints hints, AF_Dimension dim, FT_Fixed scale, FT_Pos delta ); #endif FT_LOCAL( void ) af_glyph_hints_done( AF_GlyphHints hints ); /* */ #define AF_SEGMENT_LEN( seg ) ( (seg)->max_coord - (seg)->min_coord ) #define AF_SEGMENT_DIST( seg1, seg2 ) ( ( (seg1)->pos > (seg2)->pos ) \ ? (seg1)->pos - (seg2)->pos \ : (seg2)->pos - (seg1)->pos ) FT_END_HEADER #endif /* __AFHINTS_H__ */ /* END */