lib/tatypes.h

   1 /* tatypes.h */
   2
   3 /*
   4  * Copyright (C) 2011-2013 by Werner Lemberg.
   5  *
   6  * This file is part of the ttfautohint library, and may only be used,
   7  * modified, and distributed under the terms given in `COPYING'.  By
   8  * continuing to use, modify, or distribute this file you indicate that you
   9  * have read `COPYING' and understand and accept it fully.
  10  *
  11  * The file `COPYING' mentioned in the previous paragraph is distributed
  12  * with the ttfautohint library.
  13  */
  14
  15
  16 /* originally file `aftypes.h' (2011-Mar-30) from FreeType */
  17
  18 /* heavily modified 2011 by Werner Lemberg <wl@gnu.org> */
  19
  20 #ifndef __TATYPES_H__
  21 #define __TATYPES_H__
  22
  23 #include <ft2build.h>
  24
  25 #include FT_FREETYPE_H
  26 #include FT_OUTLINE_H
  27
  28 #include "tablue.h"
  29
  30
  31 /* enable one of the following three definitions for debugging */
  32 /* #define TA_DEBUG */
  33 /* #define TA_DEBUG_HORZ */
  34 #define TA_DEBUG_VERT
  35
  36 #if defined TA_DEBUG_HORZ
  37 #  define TA_DEBUG_STARTDIM TA_DIMENSION_HORZ
  38 #  define TA_DEBUG_ENDDIM TA_DIMENSION_HORZ
  39 #  define TA_DEBUG
  40 #elif defined TA_DEBUG_VERT
  41 #  define TA_DEBUG_STARTDIM TA_DIMENSION_VERT
  42 #  define TA_DEBUG_ENDDIM TA_DIMENSION_VERT
  43 #  define TA_DEBUG
  44 #elif defined TA_DEBUG
  45 #  define TA_DEBUG_STARTDIM TA_DIMENSION_VERT
  46 #  define TA_DEBUG_ENDDIM TA_DIMENSION_HORZ
  47 #endif
  48
  49 #ifdef TA_DEBUG
  50
  51 #define TA_LOG(x) \
  52   do \
  53   { \
  54     if (_ta_debug) \
  55       _ta_message x; \
  56   } while (0)
  57
  58 void
  59 _ta_message(const char* format,
  60             ...);
  61
  62 extern int _ta_debug;
  63 extern int _ta_debug_disable_horz_hints;
  64 extern int _ta_debug_disable_vert_hints;
  65 extern int _ta_debug_disable_blue_hints;
  66 extern void* _ta_debug_hints;
  67
  68 #else /* !TA_DEBUG */
  69
  70 #define TA_LOG(x) \
  71   do { } while (0) /* nothing */
  72
  73 #endif /* !TA_DEBUG */
  74
  75
  76 #define TA_ABS(a) ((a) < 0 ? -(a) : (a))
  77
  78 /* from file `ftobjs.h' from FreeType */
  79 #define TA_PAD_FLOOR(x, n) ((x) & ~((n) - 1))
  80 #define TA_PAD_ROUND(x, n) TA_PAD_FLOOR((x) + ((n) / 2), n)
  81 #define TA_PAD_CEIL(x, n) TA_PAD_FLOOR((x) + ((n) - 1), n)
  82
  83 #define TA_PIX_FLOOR(x) ((x) & ~63)
  84 #define TA_PIX_ROUND(x) TA_PIX_FLOOR((x) + 32)
  85 #define TA_PIX_CEIL(x) TA_PIX_FLOOR((x) + 63)
  86
  87
  88 typedef struct TA_WidthRec_
  89 {
  90   FT_Pos org; /* original position/width in font units */
  91   FT_Pos cur; /* current/scaled position/width in device sub-pixels */
  92   FT_Pos fit; /* current/fitted position/width in device sub-pixels */
  93 } TA_WidthRec, *TA_Width;
  94
  95
  96 /* the auto-hinter doesn't need a very high angular accuracy */
  97 typedef FT_Int TA_Angle;
  98
  99 #define TA_ANGLE_PI 256
 100 #define TA_ANGLE_2PI (TA_ANGLE_PI * 2)
 101 #define TA_ANGLE_PI2 (TA_ANGLE_PI / 2)
 102 #define TA_ANGLE_PI4 (TA_ANGLE_PI / 4)
 103
 104 #define TA_ANGLE_DIFF(result, angle1, angle2) \
 105           do \
 106           { \
 107             TA_Angle _delta = (angle2) - (angle1); \
 108 \
 109 \
 110             _delta %= TA_ANGLE_2PI; \
 111             if (_delta < 0) \
 112               _delta += TA_ANGLE_2PI; \
 113 \
 114             if (_delta > TA_ANGLE_PI) \
 115               _delta -= TA_ANGLE_2PI; \
 116 \
 117             result = _delta; \
 118           } while (0)
 119
 120
 121 /* opaque handle to glyph-specific hints -- */
 122 /* see `tahints.h' for more details */
 123 typedef struct TA_GlyphHintsRec_* TA_GlyphHints;
 124
 125
 126 /* a scaler models the target pixel device that will receive */
 127 /* the auto-hinted glyph image */
 128 #define TA_SCALER_FLAG_NO_HORIZONTAL 0x01 /* disable horizontal hinting */
 129 #define TA_SCALER_FLAG_NO_VERTICAL 0x02 /* disable vertical hinting */
 130 #define TA_SCALER_FLAG_NO_ADVANCE 0x04 /* disable advance hinting */
 131
 132 typedef struct TA_ScalerRec_
 133 {
 134   FT_Face face; /* source font face */
 135   FT_Fixed x_scale; /* from font units to 1/64th device pixels */
 136   FT_Fixed y_scale; /* from font units to 1/64th device pixels */
 137   FT_Pos x_delta; /* in 1/64th device pixels */
 138   FT_Pos y_delta; /* in 1/64th device pixels */
 139   FT_Render_Mode render_mode; /* monochrome, anti-aliased, LCD, etc.*/
 140   FT_UInt32 flags; /* additional control flags, see above */
 141 } TA_ScalerRec, *TA_Scaler;
 142
 143 #define TA_SCALER_EQUAL_SCALES(a, b) \
 144           ((a)->x_scale == (b)->x_scale \
 145            && (a)->y_scale == (b)->y_scale \
 146            && (a)->x_delta == (b)->x_delta \
 147            && (a)->y_delta == (b)->y_delta)
 148
 149
 150 /* This is the main structure which combines writing systems and script */
 151 /* data (for a given face object, see below). */
 152
 153 typedef struct TA_WritingSystemClassRec_ const* TA_WritingSystemClass;
 154 typedef struct TA_ScriptClassRec_ const* TA_ScriptClass;
 155 typedef struct TA_FaceGlobalsRec_* TA_FaceGlobals;
 156
 157 typedef struct TA_ScriptMetricsRec_
 158 {
 159   TA_ScriptClass script_class;
 160   TA_ScalerRec scaler;
 161   FT_Bool digits_have_same_width;
 162
 163   TA_FaceGlobals globals; /* to access properties */
 164 } TA_ScriptMetricsRec, *TA_ScriptMetrics;
 165
 166
 167 /* this function parses an FT_Face to compute global metrics */
 168 /* for a specific script */
 169 typedef FT_Error
 170 (*TA_Script_InitMetricsFunc)(TA_ScriptMetrics metrics,
 171                              FT_Face face);
 172 typedef void
 173 (*TA_Script_ScaleMetricsFunc)(TA_ScriptMetrics metrics,
 174                               TA_Scaler scaler);
 175 typedef void
 176 (*TA_Script_DoneMetricsFunc)(TA_ScriptMetrics metrics);
 177 typedef FT_Error
 178 (*TA_Script_InitHintsFunc)(TA_GlyphHints hints,
 179                            TA_ScriptMetrics metrics);
 180 typedef void
 181 (*TA_Script_ApplyHintsFunc)(TA_GlyphHints hints,
 182                             FT_Outline* outline,
 183                             TA_ScriptMetrics metrics);
 184
 185
 186 /*
 187  *  In FreeType, a writing system consists of multiple scripts which can
 188  *  be handled similarly *in a typographical way*; the relationship is not
 189  *  based on history.  For example, both the Greek and the unrelated
 190  *  Armenian scripts share the same features like ascender, descender,
 191  *  x-height, etc.  Essentially, a writing system is covered by a
 192  *  submodule of the auto-fitter; it contains
 193  *
 194  *  - a specific global analyzer which computes global metrics specific to
 195  *    the script (based on script-specific characters to identify ascender
 196  *    height, x-height, etc.),
 197  *
 198  *  - a specific glyph analyzer that computes segments and edges for each
 199  *    glyph covered by the script,
 200  *
 201  *  - a specific grid-fitting algorithm that distorts the scaled glyph
 202  *    outline according to the results of the glyph analyzer.
 203  */
 204
 205 #define __TAWRTSYS_H__ /* don't load header files */
 206 #undef WRITING_SYSTEM
 207 #define WRITING_SYSTEM(ws, WS) \
 208           TA_WRITING_SYSTEM_ ## WS,
 209
 210 /* The list of known writing systems. */
 211 typedef enum TA_WritingSystem_
 212 {
 213 #include "tawrtsys.h"
 214
 215   TA_WRITING_SYSTEM_MAX /* do not remove */
 216 } TA_WritingSystem;
 217
 218 #undef __TAWRTSYS_H__
 219
 220
 221 typedef struct TA_WritingSystemClassRec_
 222 {
 223   TA_WritingSystem writing_system;
 224
 225   FT_Offset script_metrics_size;
 226   TA_Script_InitMetricsFunc script_metrics_init;
 227   TA_Script_ScaleMetricsFunc script_metrics_scale;
 228   TA_Script_DoneMetricsFunc script_metrics_done;
 229
 230   TA_Script_InitHintsFunc script_hints_init;
 231   TA_Script_ApplyHintsFunc script_hints_apply;
 232 } TA_WritingSystemClassRec;
 233
 234
 235 /*
 236  *  Each script is associated with a set of Unicode ranges which gets used
 237  *  to test whether the font face supports the script.  It also references
 238  *  the writing system it belongs to.
 239  *
 240  *  We use four-letter script tags from the OpenType specification.
 241  */
 242
 243 #undef SCRIPT
 244 #define SCRIPT(s, S) \
 245           TA_SCRIPT_ ## S,
 246
 247 /* The list of known scripts. */
 248 typedef enum TA_Script_
 249 {
 250 #include "tascript.h"
 251
 252   TA_SCRIPT_MAX /* do not remove */
 253 } TA_Script;
 254
 255
 256 typedef struct TA_Script_UniRangeRec_
 257 {
 258   FT_UInt32 first;
 259   FT_UInt32 last;
 260 } TA_Script_UniRangeRec;
 261
 262 #define TA_UNIRANGE_REC(a, b) \
 263           { (FT_UInt32)(a), (FT_UInt32)(b) }
 264
 265 typedef const TA_Script_UniRangeRec* TA_Script_UniRange;
 266
 267 typedef struct TA_ScriptClassRec_
 268 {
 269   TA_Script script;
 270   TA_Blue_Stringset blue_stringset;
 271   TA_WritingSystem writing_system;
 272
 273   TA_Script_UniRange script_uni_ranges; /* last must be { 0, 0 } */
 274   FT_UInt32 standard_char; /* for default width and height */
 275 } TA_ScriptClassRec;
 276
 277 #endif /* __TATYPES_H__ */
 278
 279 /* end of tatypes.h */