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 /* XXX */
  32 #include "hb-buffer-private.h"
  33
  34 #include "hb-ot-layout.h"
  35 #include "hb-ot-layout-private.h"
  36
  37 #include "hb-ot-layout-open-private.h"
  38 #include "hb-ot-layout-gdef-private.h"
  39 #include "hb-ot-layout-gsub-private.h"
  40 #include "hb-ot-layout-gpos-private.h"
  41
  42
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46
  47 hb_ot_layout_t *
  48 hb_ot_layout_create (void)
  49 {
  50   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  51
  52   layout->gdef = &Null(GDEF);
  53   layout->gsub = &Null(GSUB);
  54   layout->gpos = &Null(GPOS);
  55
  56   return layout;
  57 }
  58
  59 hb_ot_layout_t *
  60 hb_ot_layout_create_for_data (const char *font_data,
  61                               int         face_index)
  62 {
  63   hb_ot_layout_t *layout;
  64
  65   if (HB_UNLIKELY (font_data == NULL))
  66     return hb_ot_layout_create ();
  67
  68   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  69
  70   const OpenTypeFontFile &font = OpenTypeFontFile::get_for_data (font_data);
  71   const OpenTypeFontFace &face = font.get_face (face_index);
  72
  73   layout->gdef = &GDEF::get_for_data (font.get_table_data (face.get_table_by_tag (GDEF::Tag)));
  74   layout->gsub = &GSUB::get_for_data (font.get_table_data (face.get_table_by_tag (GSUB::Tag)));
  75   layout->gpos = &GPOS::get_for_data (font.get_table_data (face.get_table_by_tag (GPOS::Tag)));
  76
  77   return layout;
  78 }
  79
  80 void
  81 hb_ot_layout_destroy (hb_ot_layout_t *layout)
  82 {
  83   free (layout);
  84 }
  85
  86 void
  87 hb_ot_layout_set_direction (hb_ot_layout_t *layout,
  88                             hb_bool_t r2l)
  89 {
  90   layout->gpos_info.r2l = !!r2l;
  91 }
  92
  93 void
  94 hb_ot_layout_set_hinting (hb_ot_layout_t *layout,
  95                           hb_bool_t hinted)
  96 {
  97   layout->gpos_info.dvi = !hinted;
  98 }
  99
 100 void
 101 hb_ot_layout_set_scale (hb_ot_layout_t *layout,
 102                         hb_16dot16_t x_scale, hb_16dot16_t y_scale)
 103 {
 104   layout->gpos_info.x_scale = x_scale;
 105   layout->gpos_info.y_scale = y_scale;
 106 }
 107
 108 void
 109 hb_ot_layout_set_ppem (hb_ot_layout_t *layout,
 110                        unsigned int x_ppem, unsigned int y_ppem)
 111 {
 112   layout->gpos_info.x_ppem = x_ppem;
 113   layout->gpos_info.y_ppem = y_ppem;
 114 }
 115
 116
 117 /*
 118  * GDEF
 119  */
 120
 121 /* TODO the public class_t is a mess */
 122
 123 hb_bool_t
 124 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
 125 {
 126   return layout->gdef->has_glyph_classes ();
 127 }
 128
 129 HB_INTERNAL hb_bool_t
 130 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
 131 {
 132   return layout->new_gdef.len > 0;
 133 }
 134
 135 HB_INTERNAL unsigned int
 136 _hb_ot_layout_get_glyph_property (hb_ot_layout_t *layout,
 137                                   hb_codepoint_t  glyph)
 138 {
 139   hb_ot_layout_class_t klass;
 140
 141   klass = layout->gdef->get_glyph_class (glyph);
 142
 143   if (!klass && glyph < layout->new_gdef.len)
 144     klass = layout->new_gdef.klasses[glyph];
 145
 146   switch (klass) {
 147   default:
 148   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 149   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 150   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 151   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 152   case GDEF::MarkGlyph:
 153         /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 154          * introduced without a version bump, so it may not be safe */
 155         klass = layout->gdef->get_mark_attachment_type (glyph);
 156         return HB_OT_LAYOUT_GLYPH_CLASS_MARK + klass << 8;
 157   }
 158 }
 159
 160 HB_INTERNAL hb_bool_t
 161 _hb_ot_layout_check_glyph_property (hb_ot_layout_t  *layout,
 162                                     hb_glyph_info_t *ginfo,
 163                                     unsigned int     lookup_flags,
 164                                     unsigned int    *property_out)
 165 {
 166   unsigned int property;
 167
 168   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 169     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->gindex);
 170   property = ginfo->gproperty;
 171   if (property_out)
 172     *property_out = property;
 173
 174   /* Not covered, if, for example, glyph class is ligature and
 175    * lookup_flags includes LookupFlags::IgnoreLigatures
 176    */
 177   if (property & lookup_flags)
 178     return false;
 179
 180   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 181   {
 182     /* If using mark filtering sets, the high short of
 183      * lookup_flags has the set index.
 184      */
 185     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 186       return layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->gindex);
 187
 188     /* The second byte of lookup_flags has the meaning
 189      * "ignore marks of attachment type different than
 190      * the attachment type specified."
 191      */
 192     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 193       return (lookup_flags & LookupFlag::MarkAttachmentType) == (property & LookupFlag::MarkAttachmentType);
 194   }
 195
 196   return true;
 197 }
 198
 199 HB_INTERNAL hb_bool_t
 200 _hb_ot_layout_skip_mark (hb_ot_layout_t  *layout,
 201                          hb_glyph_info_t *ginfo,
 202                          unsigned int     lookup_flags,
 203                          unsigned int    *property_out)
 204 {
 205   unsigned int property;
 206
 207   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 208     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->gindex);
 209   property = ginfo->gproperty;
 210   if (property_out)
 211     *property_out = property;
 212
 213   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 214   {
 215     /* Skip mark if lookup_flags includes LookupFlags::IgnoreMarks */
 216     if (lookup_flags & LookupFlag::IgnoreMarks)
 217       return true;
 218
 219     /* If using mark filtering sets, the high short of lookup_flags has the set index. */
 220     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 221       return !layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->gindex);
 222
 223     /* The second byte of lookup_flags has the meaning "ignore marks of attachment type
 224      * different than the attachment type specified." */
 225     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 226       return (lookup_flags & LookupFlag::MarkAttachmentType) != (property & LookupFlag::MarkAttachmentType);
 227   }
 228
 229   return false;
 230 }
 231
 232 HB_INTERNAL void
 233 _hb_ot_layout_set_glyph_property (hb_ot_layout_t *layout,
 234                                   hb_codepoint_t  glyph,
 235                                   unsigned int    property)
 236 { hb_ot_layout_set_glyph_class (layout, glyph, (hb_ot_layout_glyph_class_t) (property & 0xff)); }
 237
 238
 239 hb_ot_layout_glyph_class_t
 240 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 241                               hb_codepoint_t  glyph)
 242 { return (hb_ot_layout_glyph_class_t) (_hb_ot_layout_get_glyph_property (layout, glyph) & 0xff); }
 243
 244 void
 245 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 246                               hb_codepoint_t              glyph,
 247                               hb_ot_layout_glyph_class_t  klass)
 248 {
 249   /* TODO optimize this, similar to old harfbuzz code for example */
 250
 251   hb_ot_layout_class_t gdef_klass;
 252   int len = layout->new_gdef.len;
 253
 254   if (HB_UNLIKELY (glyph > 65535))
 255     return;
 256
 257   if (glyph >= len) {
 258     int new_len;
 259     unsigned char *new_klasses;
 260
 261     new_len = len == 0 ? 120 : 2 * len;
 262     if (new_len > 65535)
 263       new_len = 65535;
 264     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 265
 266     if (HB_UNLIKELY (!new_klasses))
 267       return;
 268
 269     memset (new_klasses + len, 0, new_len - len);
 270
 271     layout->new_gdef.klasses = new_klasses;
 272     layout->new_gdef.len = new_len;
 273   }
 274
 275   switch (klass) {
 276   default:
 277   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 278   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 279   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 280   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 281   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 282   }
 283
 284   layout->new_gdef.klasses[glyph] = gdef_klass;
 285   return;
 286 }
 287
 288 void
 289 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 290                                   uint16_t        num_total_glyphs,
 291                                   hb_codepoint_t *glyphs,
 292                                   unsigned char  *klasses,
 293                                   uint16_t        count)
 294 {
 295   if (HB_UNLIKELY (!count || !glyphs || !klasses))
 296     return;
 297
 298   if (layout->new_gdef.len == 0) {
 299     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 300     layout->new_gdef.len = count;
 301   }
 302
 303   for (unsigned int i = 0; i < count; i++)
 304     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 305 }
 306
 307 hb_bool_t
 308 hb_ot_layout_get_attach_points (hb_ot_layout_t *layout,
 309                                 hb_codepoint_t  glyph,
 310                                 unsigned int   *point_count /* IN/OUT */,
 311                                 unsigned int   *point_array /* OUT */)
 312 {
 313   return layout->gdef->get_attach_points (glyph, point_count, point_array);
 314 }
 315
 316 hb_bool_t
 317 hb_ot_layout_get_lig_carets (hb_ot_layout_t *layout,
 318                              hb_codepoint_t  glyph,
 319                              unsigned int   *caret_count /* IN/OUT */,
 320                              int            *caret_array /* OUT */)
 321 {
 322   return layout->gdef->get_lig_carets (layout, glyph, caret_count, caret_array);
 323 }
 324
 325 /*
 326  * GSUB/GPOS
 327  */
 328
 329 static const GSUBGPOS&
 330 get_gsubgpos_table (hb_ot_layout_t            *layout,
 331                     hb_ot_layout_table_type_t  table_type)
 332 {
 333   switch (table_type) {
 334     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 335     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 336     default:                           return Null(GSUBGPOS);
 337   }
 338 }
 339
 340
 341 unsigned int
 342 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 343                                      hb_ot_layout_table_type_t  table_type)
 344 {
 345   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 346
 347   return g.get_script_count ();
 348 }
 349
 350 hb_tag_t
 351 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 352                                    hb_ot_layout_table_type_t  table_type,
 353                                    unsigned int               script_index)
 354 {
 355   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 356
 357   return g.get_script_tag (script_index);
 358 }
 359
 360 hb_bool_t
 361 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 362                                 hb_ot_layout_table_type_t  table_type,
 363                                 hb_tag_t                   script_tag,
 364                                 unsigned int              *script_index)
 365 {
 366   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 367   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 368
 369   if (g.find_script_index (script_tag, script_index))
 370     return TRUE;
 371
 372   /* try finding 'DFLT' */
 373   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 374     return FALSE;
 375
 376   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 377   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 378     return FALSE;
 379
 380   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 381   return FALSE;
 382 }
 383
 384 unsigned int
 385 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 386                                       hb_ot_layout_table_type_t  table_type)
 387 {
 388   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 389
 390   return g.get_feature_count ();
 391 }
 392
 393 hb_tag_t
 394 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 395                                     hb_ot_layout_table_type_t  table_type,
 396                                     unsigned int               feature_index)
 397 {
 398   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 399
 400   return g.get_feature_tag (feature_index);
 401 }
 402
 403 hb_bool_t
 404 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 405                                  hb_ot_layout_table_type_t  table_type,
 406                                  hb_tag_t                   feature_tag,
 407                                  unsigned int              *feature_index)
 408 {
 409   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 410   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 411
 412   if (g.find_feature_index (feature_tag, feature_index))
 413     return TRUE;
 414
 415   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 416   return FALSE;
 417 }
 418
 419 unsigned int
 420 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 421                                      hb_ot_layout_table_type_t  table_type)
 422 {
 423   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 424
 425   return g.get_lookup_count ();
 426 }
 427
 428
 429 unsigned int
 430 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 431                                         hb_ot_layout_table_type_t  table_type,
 432                                         unsigned int               script_index)
 433 {
 434   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 435
 436   return s.get_lang_sys_count ();
 437 }
 438
 439 hb_tag_t
 440 hb_ot_layout_script_get_language_tag (hb_ot_layout_t            *layout,
 441                                       hb_ot_layout_table_type_t  table_type,
 442                                       unsigned int               script_index,
 443                                       unsigned int               language_index)
 444 {
 445   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 446
 447   return s.get_lang_sys_tag (language_index);
 448 }
 449
 450 hb_bool_t
 451 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 452                                    hb_ot_layout_table_type_t  table_type,
 453                                    unsigned int               script_index,
 454                                    hb_tag_t                   language_tag,
 455                                    unsigned int              *language_index)
 456 {
 457   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 458   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 459
 460   if (s.find_lang_sys_index (language_tag, language_index))
 461     return TRUE;
 462
 463   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 464   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 465     return FALSE;
 466
 467   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 468   return FALSE;
 469 }
 470
 471 hb_bool_t
 472 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 473                                                   hb_ot_layout_table_type_t  table_type,
 474                                                   unsigned int               script_index,
 475                                                   unsigned int               language_index,
 476                                                   unsigned int              *feature_index)
 477 {
 478   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 479
 480   if (feature_index) *feature_index = l.get_required_feature_index ();
 481
 482   return l.has_required_feature ();
 483 }
 484
 485 unsigned int
 486 hb_ot_layout_language_get_feature_count (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 {
 491   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 492
 493   return l.get_feature_count ();
 494 }
 495
 496 unsigned int
 497 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 498                                          hb_ot_layout_table_type_t  table_type,
 499                                          unsigned int               script_index,
 500                                          unsigned int               language_index,
 501                                          unsigned int               num_feature)
 502 {
 503   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 504   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 505
 506   return l.get_feature_index (num_feature);
 507 }
 508
 509 hb_tag_t
 510 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 511                                        hb_ot_layout_table_type_t  table_type,
 512                                        unsigned int               script_index,
 513                                        unsigned int               language_index,
 514                                        unsigned int               num_feature)
 515 {
 516   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 517   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 518   unsigned int feature_index = l.get_feature_index (num_feature);
 519
 520   return g.get_feature_tag (feature_index);
 521 }
 522
 523
 524 hb_bool_t
 525 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 526                                     hb_ot_layout_table_type_t  table_type,
 527                                     unsigned int               script_index,
 528                                     unsigned int               language_index,
 529                                     hb_tag_t                   feature_tag,
 530                                     unsigned int              *feature_index)
 531 {
 532   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 533   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 534   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 535
 536   unsigned int num_features = l.get_feature_count ();
 537   for (unsigned int i = 0; i < num_features; i++) {
 538     unsigned int f_index = l.get_feature_index (i);
 539
 540     if (feature_tag == g.get_feature_tag (f_index)) {
 541       if (feature_index) *feature_index = f_index;
 542       return TRUE;
 543     }
 544   }
 545
 546   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 547   return FALSE;
 548 }
 549
 550 unsigned int
 551 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 552                                        hb_ot_layout_table_type_t  table_type,
 553                                        unsigned int               feature_index)
 554 {
 555   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 556   const Feature &f = g.get_feature (feature_index);
 557
 558   return f.get_lookup_count ();
 559 }
 560
 561 unsigned int
 562 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 563                                        hb_ot_layout_table_type_t  table_type,
 564                                        unsigned int               feature_index,
 565                                        unsigned int               num_lookup)
 566 {
 567   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 568   const Feature &f = g.get_feature (feature_index);
 569
 570   return f.get_lookup_index (num_lookup);
 571 }
 572
 573 /*
 574  * GSUB
 575  */
 576
 577 hb_bool_t
 578 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 579                                 hb_buffer_t                 *buffer,
 580                                 unsigned int                 lookup_index,
 581                                 hb_ot_layout_feature_mask_t  mask)
 582 {
 583   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 584 }
 585
 586 /*
 587  * GPOS
 588  */
 589
 590 hb_bool_t
 591 hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
 592                                 hb_buffer_t                 *buffer,
 593                                 unsigned int                 lookup_index,
 594                                 hb_ot_layout_feature_mask_t  mask)
 595 {
 596   return layout->gpos->position_lookup (layout, buffer, lookup_index, mask);
 597 }