lib/taglobal.c

   1 /* taglobal.c */
   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 `afglobal.c' (2011-Mar-28) from FreeType */
  17
  18 /* heavily modified 2011 by Werner Lemberg <wl@gnu.org> */
  19
  20 #include <stdlib.h>
  21
  22 #include "taglobal.h"
  23
  24 /* get writing system specific header files */
  25 #undef WRITING_SYSTEM
  26 #define WRITING_SYSTEM(ws, WS) /* empty */
  27 #include "tawrtsys.h"
  28
  29
  30 #undef WRITING_SYSTEM
  31 #define WRITING_SYSTEM(ws, WS) \
  32           &ta_ ## ws ## _writing_system_class,
  33
  34 TA_WritingSystemClass const ta_writing_system_classes[] =
  35 {
  36
  37 #include "tawrtsys.h"
  38
  39   NULL /* do not remove */
  40 };
  41
  42
  43 #undef SCRIPT
  44 #define SCRIPT(s, S, d) \
  45           &ta_ ## s ## _script_class,
  46
  47 TA_ScriptClass const ta_script_classes[] =
  48 {
  49
  50 #include "tascript.h"
  51
  52   NULL  /* do not remove */
  53 };
  54
  55
  56 #ifdef TA_DEBUG
  57
  58 #undef SCRIPT
  59 #define SCRIPT(s, S, d) #s,
  60
  61 const char* ta_script_names[] =
  62 {
  63
  64 #include "tascript.h"
  65
  66 };
  67
  68 #endif /* TA_DEBUG */
  69
  70
  71 /* Compute the script index of each glyph within a given face. */
  72
  73 static FT_Error
  74 ta_face_globals_compute_script_coverage(TA_FaceGlobals globals)
  75 {
  76   FT_Error error;
  77   FT_Face face = globals->face;
  78   FT_CharMap old_charmap = face->charmap;
  79   FT_Byte* gscripts = globals->glyph_scripts;
  80   FT_UInt ss;
  81   FT_UInt i;
  82
  83
  84   /* the value TA_SCRIPT_NONE means `uncovered glyph' */
  85   memset(globals->glyph_scripts, TA_SCRIPT_NONE, globals->glyph_count);
  86
  87   error = FT_Select_Charmap(face, FT_ENCODING_UNICODE);
  88   if (error)
  89   {
  90     /* ignore this error; we simply use the fallback script */
  91     /* XXX: Shouldn't we rather disable hinting? */
  92     error = FT_Err_Ok;
  93     goto Exit;
  94   }
  95
  96   /* scan each script in a Unicode charmap */
  97   for (ss = 0; ta_script_classes[ss]; ss++)
  98   {
  99     TA_ScriptClass script_class = ta_script_classes[ss];
 100     TA_Script_UniRange range;
 101
 102
 103     if (script_class->script_uni_ranges == NULL)
 104       continue;
 105
 106     /* scan all Unicode points in the range and */
 107     /* set the corresponding glyph script index */
 108     for (range = script_class->script_uni_ranges; range->first != 0; range++)
 109     {
 110       FT_ULong charcode = range->first;
 111       FT_UInt gindex;
 112
 113
 114       gindex = FT_Get_Char_Index(face, charcode);
 115
 116       if (gindex != 0
 117           && gindex < (FT_ULong)globals->glyph_count
 118           && gscripts[gindex] == TA_SCRIPT_NONE)
 119         gscripts[gindex] = (FT_Byte)ss;
 120
 121       for (;;)
 122       {
 123         charcode = FT_Get_Next_Char(face, charcode, &gindex);
 124
 125         if (gindex == 0 || charcode > range->last)
 126           break;
 127
 128         if (gindex < (FT_ULong)globals->glyph_count
 129             && gscripts[gindex] == TA_SCRIPT_NONE)
 130           gscripts[gindex] = (FT_Byte)ss;
 131       }
 132     }
 133   }
 134
 135   /* mark ASCII digits */
 136   for (i = 0x30; i <= 0x39; i++)
 137   {
 138     FT_UInt gindex = FT_Get_Char_Index(face, i);
 139
 140
 141     if (gindex != 0
 142         && gindex < (FT_ULong)globals->glyph_count)
 143       gscripts[gindex] |= TA_DIGIT;
 144   }
 145
 146 Exit:
 147   /* by default, all uncovered glyphs are set to the fallback script */
 148   /* XXX: Shouldn't we disable hinting or do something similar? */
 149   if (globals->font->fallback_script != TA_SCRIPT_NONE)
 150   {
 151     FT_Long nn;
 152
 153
 154     for (nn = 0; nn < globals->glyph_count; nn++)
 155     {
 156       if ((gscripts[nn] & ~TA_DIGIT) == TA_SCRIPT_NONE)
 157       {
 158         gscripts[nn] &= ~TA_SCRIPT_NONE;
 159         gscripts[nn] |= globals->font->fallback_script;
 160       }
 161     }
 162   }
 163
 164   FT_Set_Charmap(face, old_charmap);
 165   return error;
 166 }
 167
 168
 169 FT_Error
 170 ta_face_globals_new(FT_Face face,
 171                     TA_FaceGlobals *aglobals,
 172                     FONT* font)
 173 {
 174   FT_Error error;
 175   TA_FaceGlobals globals;
 176
 177
 178   globals = (TA_FaceGlobals)calloc(1, sizeof (TA_FaceGlobalsRec) +
 179                                       face->num_glyphs * sizeof (FT_Byte));
 180   if (!globals)
 181   {
 182     error = FT_Err_Out_Of_Memory;
 183     goto Err;
 184   }
 185
 186   globals->face = face;
 187   globals->glyph_count = face->num_glyphs;
 188   globals->glyph_scripts = (FT_Byte*)(globals + 1);
 189   globals->font = font;
 190
 191   error = ta_face_globals_compute_script_coverage(globals);
 192   if (error)
 193   {
 194     ta_face_globals_free(globals);
 195     globals = NULL;
 196   }
 197
 198   globals->increase_x_height = TA_PROP_INCREASE_X_HEIGHT_MAX;
 199
 200 Err:
 201   *aglobals = globals;
 202   return error;
 203 }
 204
 205
 206 void
 207 ta_face_globals_free(TA_FaceGlobals globals)
 208 {
 209   if (globals)
 210   {
 211     FT_UInt nn;
 212
 213
 214     for (nn = 0; nn < TA_SCRIPT_MAX; nn++)
 215     {
 216       if (globals->metrics[nn])
 217       {
 218         TA_ScriptClass script_class =
 219           ta_script_classes[nn];
 220         TA_WritingSystemClass writing_system_class =
 221           ta_writing_system_classes[script_class->writing_system];
 222
 223
 224         if (writing_system_class->script_metrics_done)
 225           writing_system_class->script_metrics_done(globals->metrics[nn]);
 226
 227         free(globals->metrics[nn]);
 228         globals->metrics[nn] = NULL;
 229       }
 230     }
 231
 232     globals->glyph_count = 0;
 233     globals->glyph_scripts = NULL; /* no need to free this one! */
 234     globals->face = NULL;
 235
 236     free(globals);
 237     globals = NULL;
 238   }
 239 }
 240
 241
 242 FT_Error
 243 ta_face_globals_get_metrics(TA_FaceGlobals globals,
 244                             FT_UInt gindex,
 245                             FT_UInt options,
 246                             TA_ScriptMetrics *ametrics)
 247 {
 248   TA_ScriptMetrics metrics = NULL;
 249   TA_Script script = (TA_Script)(options & 15);
 250   TA_ScriptClass script_class;
 251   TA_WritingSystemClass writing_system_class;
 252   FT_Error error = FT_Err_Ok;
 253
 254
 255   if (gindex >= (FT_ULong)globals->glyph_count)
 256   {
 257     error = FT_Err_Invalid_Argument;
 258     goto Exit;
 259   }
 260
 261   /* if we have a forced script (via `options'), use it, */
 262   /* otherwise look into `glyph_scripts' array */
 263   if (script == TA_SCRIPT_DFLT || script + 1 >= TA_SCRIPT_MAX)
 264     script = (TA_Script)(globals->glyph_scripts[gindex] & TA_SCRIPT_NONE);
 265
 266   script_class =
 267     ta_script_classes[script];
 268   writing_system_class =
 269     ta_writing_system_classes[script_class->writing_system];
 270
 271   metrics = globals->metrics[script];
 272   if (metrics == NULL)
 273   {
 274     /* create the global metrics object if necessary */
 275     metrics = (TA_ScriptMetrics)
 276                 calloc(1, writing_system_class->script_metrics_size);
 277     if (!metrics)
 278     {
 279       error = FT_Err_Out_Of_Memory;
 280       goto Exit;
 281     }
 282
 283     metrics->script_class = script_class;
 284     metrics->globals = globals;
 285
 286     if (writing_system_class->script_metrics_init)
 287     {
 288       error = writing_system_class->script_metrics_init(metrics,
 289                                                         globals->face);
 290       if (error)
 291       {
 292         if (writing_system_class->script_metrics_done)
 293           writing_system_class->script_metrics_done(metrics);
 294
 295         free(metrics);
 296         metrics = NULL;
 297         goto Exit;
 298       }
 299     }
 300
 301     globals->metrics[script] = metrics;
 302   }
 303
 304 Exit:
 305   *ametrics = metrics;
 306
 307   return error;
 308 }
 309
 310
 311 FT_Bool
 312 ta_face_globals_is_digit(TA_FaceGlobals globals,
 313                          FT_UInt gindex)
 314 {
 315   if (gindex < (FT_ULong)globals->glyph_count)
 316     return (FT_Bool)(globals->glyph_scripts[gindex] & TA_DIGIT);
 317
 318   return (FT_Bool)0;
 319 }
 320
 321 /* end of taglobal.c */