src/hb-ot-layout.cc

   1 /*
   2  * Copyright (C) 1998-2004  David Turner and Werner Lemberg
   3  * Copyright (C) 2006  Behdad Esfahbod
   4  * Copyright (C) 2007,2008,2009  Red Hat, Inc.
   5  *
   6  *  This is part of HarfBuzz, an OpenType Layout engine library.
   7  *
   8  * Permission is hereby granted, without written agreement and without
   9  * license or royalty fees, to use, copy, modify, and distribute this
  10  * software and its documentation for any purpose, provided that the
  11  * above copyright notice and the following two paragraphs appear in
  12  * all copies of this software.
  13  *
  14  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  17  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  18  * DAMAGE.
  19  *
  20  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  21  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  22  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  23  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  25  *
  26  * Red Hat Author(s): Behdad Esfahbod
  27  */
  28
  29 #define HB_OT_LAYOUT_CC
  30
  31 #include "hb-ot-layout-private.h"
  32
  33 #include "hb-ot-layout-open-private.h"
  34 #include "hb-ot-layout-gdef-private.h"
  35 #include "hb-ot-layout-gsub-private.h"
  36 #include "hb-ot-layout-gpos-private.h"
  37
  38
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42
  43 hb_ot_layout_t *
  44 hb_ot_layout_create (void)
  45 {
  46   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  47
  48   layout->gdef = &Null(GDEF);
  49   layout->gsub = &Null(GSUB);
  50   layout->gpos = &Null(GPOS);
  51
  52   return layout;
  53 }
  54
  55 hb_bool_t
  56 hb_ot_layout_has_substitution (hb_ot_layout_t *layout)
  57 {
  58   return layout->gsub != &Null(GSUB);
  59 }
  60
  61 hb_bool_t
  62 hb_ot_layout_has_positioning (hb_ot_layout_t *layout)
  63 {
  64   return layout->gpos != &Null(GPOS);
  65 }
  66
  67 hb_ot_layout_t *
  68 hb_ot_layout_create_for_data (const char *font_data,
  69                               int         face_index)
  70 {
  71   hb_ot_layout_t *layout;
  72
  73   if (HB_UNLIKELY (font_data == NULL))
  74     return hb_ot_layout_create ();
  75
  76   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  77
  78   const OpenTypeFontFile &font = OpenTypeFontFile::get_for_data (font_data);
  79   const OpenTypeFontFace &face = font.get_face (face_index);
  80
  81   layout->gdef = &GDEF::get_for_data (font.get_table_data (face.get_table_by_tag (GDEF::Tag)));
  82   layout->gsub = &GSUB::get_for_data (font.get_table_data (face.get_table_by_tag (GSUB::Tag)));
  83   layout->gpos = &GPOS::get_for_data (font.get_table_data (face.get_table_by_tag (GPOS::Tag)));
  84
  85   return layout;
  86 }
  87
  88 hb_ot_layout_t *
  89 hb_ot_layout_create_for_tables (const char *gdef_data,
  90                                 const char *gsub_data,
  91                                 const char *gpos_data)
  92 {
  93   hb_ot_layout_t *layout;
  94
  95   if (HB_UNLIKELY (gdef_data == NULL && gsub_data == NULL && gpos_data == NULL))
  96     return hb_ot_layout_create ();
  97
  98   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  99
 100   layout->gdef = &GDEF::get_for_data (gdef_data);
 101   layout->gsub = &GSUB::get_for_data (gsub_data);
 102   layout->gpos = &GPOS::get_for_data (gpos_data);
 103
 104   return layout;
 105 }
 106
 107 void
 108 hb_ot_layout_destroy (hb_ot_layout_t *layout)
 109 {
 110   free (layout);
 111 }
 112
 113 void
 114 hb_ot_layout_set_scale (hb_ot_layout_t *layout,
 115                         hb_16dot16_t x_scale, hb_16dot16_t y_scale)
 116 {
 117   layout->gpos_info.x_scale = x_scale;
 118   layout->gpos_info.y_scale = y_scale;
 119 }
 120
 121 void
 122 hb_ot_layout_set_ppem (hb_ot_layout_t *layout,
 123                        unsigned int x_ppem, unsigned int y_ppem)
 124 {
 125   layout->gpos_info.x_ppem = x_ppem;
 126   layout->gpos_info.y_ppem = y_ppem;
 127 }
 128
 129
 130 /*
 131  * GDEF
 132  */
 133
 134 /* TODO the public class_t is a mess */
 135
 136 hb_bool_t
 137 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
 138 {
 139   return layout->gdef->has_glyph_classes ();
 140 }
 141
 142 HB_INTERNAL hb_bool_t
 143 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
 144 {
 145   return layout->new_gdef.len > 0;
 146 }
 147
 148 HB_INTERNAL unsigned int
 149 _hb_ot_layout_get_glyph_property (hb_ot_layout_t *layout,
 150                                   hb_codepoint_t  glyph)
 151 {
 152   hb_ot_layout_class_t klass;
 153
 154   klass = layout->gdef->get_glyph_class (glyph);
 155
 156   if (!klass && glyph < layout->new_gdef.len)
 157     klass = layout->new_gdef.klasses[glyph];
 158
 159   switch (klass) {
 160   default:
 161   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 162   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 163   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 164   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 165   case GDEF::MarkGlyph:
 166         /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 167          * introduced without a version bump, so it may not be safe */
 168         klass = layout->gdef->get_mark_attachment_type (glyph);
 169         return HB_OT_LAYOUT_GLYPH_CLASS_MARK + (klass << 8);
 170   }
 171 }
 172
 173 HB_INTERNAL hb_bool_t
 174 _hb_ot_layout_check_glyph_property (hb_ot_layout_t  *layout,
 175                                     hb_internal_glyph_info_t *ginfo,
 176                                     unsigned int     lookup_flags,
 177                                     unsigned int    *property_out)
 178 {
 179   unsigned int property;
 180
 181   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 182     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->codepoint);
 183   property = ginfo->gproperty;
 184   if (property_out)
 185     *property_out = property;
 186
 187   /* Not covered, if, for example, glyph class is ligature and
 188    * lookup_flags includes LookupFlags::IgnoreLigatures
 189    */
 190   if (property & lookup_flags)
 191     return false;
 192
 193   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 194   {
 195     /* If using mark filtering sets, the high short of
 196      * lookup_flags has the set index.
 197      */
 198     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 199       return layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->codepoint);
 200
 201     /* The second byte of lookup_flags has the meaning
 202      * "ignore marks of attachment type different than
 203      * the attachment type specified."
 204      */
 205     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 206       return (lookup_flags & LookupFlag::MarkAttachmentType) == (property & LookupFlag::MarkAttachmentType);
 207   }
 208
 209   return true;
 210 }
 211
 212 HB_INTERNAL hb_bool_t
 213 _hb_ot_layout_skip_mark (hb_ot_layout_t  *layout,
 214                          hb_internal_glyph_info_t *ginfo,
 215                          unsigned int     lookup_flags,
 216                          unsigned int    *property_out)
 217 {
 218   unsigned int property;
 219
 220   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 221     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->codepoint);
 222   property = ginfo->gproperty;
 223   if (property_out)
 224     *property_out = property;
 225
 226   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 227   {
 228     /* Skip mark if lookup_flags includes LookupFlags::IgnoreMarks */
 229     if (lookup_flags & LookupFlag::IgnoreMarks)
 230       return true;
 231
 232     /* If using mark filtering sets, the high short of lookup_flags has the set index. */
 233     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 234       return !layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->codepoint);
 235
 236     /* The second byte of lookup_flags has the meaning "ignore marks of attachment type
 237      * different than the attachment type specified." */
 238     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 239       return (lookup_flags & LookupFlag::MarkAttachmentType) != (property & LookupFlag::MarkAttachmentType);
 240   }
 241
 242   return false;
 243 }
 244
 245 HB_INTERNAL void
 246 _hb_ot_layout_set_glyph_property (hb_ot_layout_t *layout,
 247                                   hb_codepoint_t  glyph,
 248                                   unsigned int    property)
 249 { hb_ot_layout_set_glyph_class (layout, glyph, (hb_ot_layout_glyph_class_t) (property & 0xff)); }
 250
 251
 252 hb_ot_layout_glyph_class_t
 253 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 254                               hb_codepoint_t  glyph)
 255 { return (hb_ot_layout_glyph_class_t) (_hb_ot_layout_get_glyph_property (layout, glyph) & 0xff); }
 256
 257 void
 258 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 259                               hb_codepoint_t              glyph,
 260                               hb_ot_layout_glyph_class_t  klass)
 261 {
 262   /* TODO optimize this? similar to old harfbuzz code for example */
 263
 264   hb_ot_layout_class_t gdef_klass;
 265   int len = layout->new_gdef.len;
 266
 267   if (HB_UNLIKELY (glyph > 65535))
 268     return;
 269
 270   /* XXX this is not threadsafe */
 271   if (glyph >= len) {
 272     int new_len;
 273     unsigned char *new_klasses;
 274
 275     new_len = len == 0 ? 120 : 2 * len;
 276     if (new_len > 65535)
 277       new_len = 65535;
 278     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 279
 280     if (HB_UNLIKELY (!new_klasses))
 281       return;
 282
 283     memset (new_klasses + len, 0, new_len - len);
 284
 285     layout->new_gdef.klasses = new_klasses;
 286     layout->new_gdef.len = new_len;
 287   }
 288
 289   switch (klass) {
 290   default:
 291   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 292   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 293   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 294   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 295   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 296   }
 297
 298   layout->new_gdef.klasses[glyph] = gdef_klass;
 299   return;
 300 }
 301
 302 void
 303 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 304                                   uint16_t        num_total_glyphs,
 305                                   hb_codepoint_t *glyphs,
 306                                   unsigned char  *klasses,
 307                                   uint16_t        count)
 308 {
 309   if (HB_UNLIKELY (!count || !glyphs || !klasses))
 310     return;
 311
 312   if (layout->new_gdef.len == 0) {
 313     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 314     layout->new_gdef.len = count;
 315   }
 316
 317   for (unsigned int i = 0; i < count; i++)
 318     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 319 }
 320
 321 hb_bool_t
 322 hb_ot_layout_get_attach_points (hb_ot_layout_t *layout,
 323                                 hb_codepoint_t  glyph,
 324                                 unsigned int   *point_count /* IN/OUT */,
 325                                 unsigned int   *point_array /* OUT */)
 326 {
 327   return layout->gdef->get_attach_points (glyph, point_count, point_array);
 328 }
 329
 330 hb_bool_t
 331 hb_ot_layout_get_lig_carets (hb_ot_layout_t *layout,
 332                              hb_codepoint_t  glyph,
 333                              unsigned int   *caret_count /* IN/OUT */,
 334                              int            *caret_array /* OUT */)
 335 {
 336   return layout->gdef->get_lig_carets (layout, glyph, caret_count, caret_array);
 337 }
 338
 339 /*
 340  * GSUB/GPOS
 341  */
 342
 343 static const GSUBGPOS&
 344 get_gsubgpos_table (hb_ot_layout_t            *layout,
 345                     hb_ot_layout_table_type_t  table_type)
 346 {
 347   switch (table_type) {
 348     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 349     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 350     default:                           return Null(GSUBGPOS);
 351   }
 352 }
 353
 354
 355 unsigned int
 356 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 357                                      hb_ot_layout_table_type_t  table_type)
 358 {
 359   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 360
 361   return g.get_script_count ();
 362 }
 363
 364 hb_tag_t
 365 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 366                                    hb_ot_layout_table_type_t  table_type,
 367                                    unsigned int               script_index)
 368 {
 369   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 370
 371   return g.get_script_tag (script_index);
 372 }
 373
 374 hb_bool_t
 375 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 376                                 hb_ot_layout_table_type_t  table_type,
 377                                 hb_tag_t                   script_tag,
 378                                 unsigned int              *script_index)
 379 {
 380   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 381   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 382
 383   if (g.find_script_index (script_tag, script_index))
 384     return TRUE;
 385
 386   /* try finding 'DFLT' */
 387   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 388     return FALSE;
 389
 390   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 391   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 392     return FALSE;
 393
 394   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 395   return FALSE;
 396 }
 397
 398 unsigned int
 399 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 400                                       hb_ot_layout_table_type_t  table_type)
 401 {
 402   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 403
 404   return g.get_feature_count ();
 405 }
 406
 407 hb_tag_t
 408 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 409                                     hb_ot_layout_table_type_t  table_type,
 410                                     unsigned int               feature_index)
 411 {
 412   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 413
 414   return g.get_feature_tag (feature_index);
 415 }
 416
 417 hb_bool_t
 418 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 419                                  hb_ot_layout_table_type_t  table_type,
 420                                  hb_tag_t                   feature_tag,
 421                                  unsigned int              *feature_index)
 422 {
 423   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 424   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 425
 426   if (g.find_feature_index (feature_tag, feature_index))
 427     return TRUE;
 428
 429   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 430   return FALSE;
 431 }
 432
 433 unsigned int
 434 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 435                                      hb_ot_layout_table_type_t  table_type)
 436 {
 437   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 438
 439   return g.get_lookup_count ();
 440 }
 441
 442
 443 unsigned int
 444 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 445                                         hb_ot_layout_table_type_t  table_type,
 446                                         unsigned int               script_index)
 447 {
 448   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 449
 450   return s.get_lang_sys_count ();
 451 }
 452
 453 hb_tag_t
 454 hb_ot_layout_script_get_language_tag (hb_ot_layout_t            *layout,
 455                                       hb_ot_layout_table_type_t  table_type,
 456                                       unsigned int               script_index,
 457                                       unsigned int               language_index)
 458 {
 459   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 460
 461   return s.get_lang_sys_tag (language_index);
 462 }
 463
 464 hb_bool_t
 465 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 466                                    hb_ot_layout_table_type_t  table_type,
 467                                    unsigned int               script_index,
 468                                    hb_tag_t                   language_tag,
 469                                    unsigned int              *language_index)
 470 {
 471   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 472   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 473
 474   if (s.find_lang_sys_index (language_tag, language_index))
 475     return TRUE;
 476
 477   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 478   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 479     return FALSE;
 480
 481   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 482   return FALSE;
 483 }
 484
 485 hb_bool_t
 486 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 487                                                   hb_ot_layout_table_type_t  table_type,
 488                                                   unsigned int               script_index,
 489                                                   unsigned int               language_index,
 490                                                   unsigned int              *feature_index)
 491 {
 492   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 493
 494   if (feature_index) *feature_index = l.get_required_feature_index ();
 495
 496   return l.has_required_feature ();
 497 }
 498
 499 unsigned int
 500 hb_ot_layout_language_get_feature_count (hb_ot_layout_t            *layout,
 501                                          hb_ot_layout_table_type_t  table_type,
 502                                          unsigned int               script_index,
 503                                          unsigned int               language_index)
 504 {
 505   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 506
 507   return l.get_feature_count ();
 508 }
 509
 510 unsigned int
 511 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 512                                          hb_ot_layout_table_type_t  table_type,
 513                                          unsigned int               script_index,
 514                                          unsigned int               language_index,
 515                                          unsigned int               num_feature)
 516 {
 517   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 518   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 519
 520   return l.get_feature_index (num_feature);
 521 }
 522
 523 hb_tag_t
 524 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 525                                        hb_ot_layout_table_type_t  table_type,
 526                                        unsigned int               script_index,
 527                                        unsigned int               language_index,
 528                                        unsigned int               num_feature)
 529 {
 530   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 531   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 532   unsigned int feature_index = l.get_feature_index (num_feature);
 533
 534   return g.get_feature_tag (feature_index);
 535 }
 536
 537
 538 hb_bool_t
 539 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 540                                     hb_ot_layout_table_type_t  table_type,
 541                                     unsigned int               script_index,
 542                                     unsigned int               language_index,
 543                                     hb_tag_t                   feature_tag,
 544                                     unsigned int              *feature_index)
 545 {
 546   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 547   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 548   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 549
 550   unsigned int num_features = l.get_feature_count ();
 551   for (unsigned int i = 0; i < num_features; i++) {
 552     unsigned int f_index = l.get_feature_index (i);
 553
 554     if (feature_tag == g.get_feature_tag (f_index)) {
 555       if (feature_index) *feature_index = f_index;
 556       return TRUE;
 557     }
 558   }
 559
 560   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 561   return FALSE;
 562 }
 563
 564 unsigned int
 565 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 566                                        hb_ot_layout_table_type_t  table_type,
 567                                        unsigned int               feature_index)
 568 {
 569   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 570   const Feature &f = g.get_feature (feature_index);
 571
 572   return f.get_lookup_count ();
 573 }
 574
 575 unsigned int
 576 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 577                                        hb_ot_layout_table_type_t  table_type,
 578                                        unsigned int               feature_index,
 579                                        unsigned int               num_lookup)
 580 {
 581   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 582   const Feature &f = g.get_feature (feature_index);
 583
 584   return f.get_lookup_index (num_lookup);
 585 }
 586
 587 /*
 588  * GSUB
 589  */
 590
 591 hb_bool_t
 592 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 593                                 hb_buffer_t                 *buffer,
 594                                 unsigned int                 lookup_index,
 595                                 hb_ot_layout_feature_mask_t  mask)
 596 {
 597   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 598 }
 599
 600 /*
 601  * GPOS
 602  */
 603
 604 hb_bool_t
 605 hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
 606                                 hb_buffer_t                 *buffer,
 607                                 unsigned int                 lookup_index,
 608                                 hb_ot_layout_feature_mask_t  mask)
 609 {
 610   return layout->gpos->position_lookup (layout, buffer, lookup_index, mask);
 611 }