--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/autofit/afhints.h Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,468 @@
+/***************************************************************************/
+/* */
+/* 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 FT_DEBUG_AUTOFIT
+
+#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 /* !FT_DEBUG_AUTOFIT */
+
+#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 /* !FT_DEBUG_AUTOFIT */
+
+
+ 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 */