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_bool_t
  60 hb_ot_layout_has_substitution (hb_ot_layout_t *layout)
  61 {
  62   return layout->gsub != &Null(GSUB);
  63 }
  64
  65 hb_bool_t
  66 hb_ot_layout_has_positioning (hb_ot_layout_t *layout)
  67 {
  68   return layout->gpos != &Null(GPOS);
  69 }
  70
  71 hb_ot_layout_t *
  72 hb_ot_layout_create_for_data (const char *font_data,
  73                               int         face_index)
  74 {
  75   hb_ot_layout_t *layout;
  76
  77   if (HB_UNLIKELY (font_data == NULL))
  78     return hb_ot_layout_create ();
  79
  80   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  81
  82   const OpenTypeFontFile &font = OpenTypeFontFile::get_for_data (font_data);
  83   const OpenTypeFontFace &face = font.get_face (face_index);
  84
  85   layout->gdef = &GDEF::get_for_data (font.get_table_data (face.get_table_by_tag (GDEF::Tag)));
  86   layout->gsub = &GSUB::get_for_data (font.get_table_data (face.get_table_by_tag (GSUB::Tag)));
  87   layout->gpos = &GPOS::get_for_data (font.get_table_data (face.get_table_by_tag (GPOS::Tag)));
  88
  89   return layout;
  90 }
  91
  92 hb_ot_layout_t *
  93 hb_ot_layout_create_for_tables (const char *gdef_data,
  94                                 const char *gsub_data,
  95                                 const char *gpos_data)
  96 {
  97   hb_ot_layout_t *layout;
  98
  99   if (HB_UNLIKELY (gdef_data == NULL && gsub_data == NULL && gpos_data == NULL))
 100     return hb_ot_layout_create ();
 101
 102   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
 103
 104   layout->gdef = &GDEF::get_for_data (gdef_data);
 105   layout->gsub = &GSUB::get_for_data (gsub_data);
 106   layout->gpos = &GPOS::get_for_data (gpos_data);
 107
 108   return layout;
 109 }
 110
 111 void
 112 hb_ot_layout_destroy (hb_ot_layout_t *layout)
 113 {
 114   free (layout);
 115 }
 116
 117 void
 118 hb_ot_layout_set_scale (hb_ot_layout_t *layout,
 119                         hb_16dot16_t x_scale, hb_16dot16_t y_scale)
 120 {
 121   layout->gpos_info.x_scale = x_scale;
 122   layout->gpos_info.y_scale = y_scale;
 123 }
 124
 125 void
 126 hb_ot_layout_set_ppem (hb_ot_layout_t *layout,
 127                        unsigned int x_ppem, unsigned int y_ppem)
 128 {
 129   layout->gpos_info.x_ppem = x_ppem;
 130   layout->gpos_info.y_ppem = y_ppem;
 131 }
 132
 133
 134 /*
 135  * GDEF
 136  */
 137
 138 /* TODO the public class_t is a mess */
 139
 140 hb_bool_t
 141 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
 142 {
 143   return layout->gdef->has_glyph_classes ();
 144 }
 145
 146 HB_INTERNAL hb_bool_t
 147 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
 148 {
 149   return layout->new_gdef.len > 0;
 150 }
 151
 152 HB_INTERNAL unsigned int
 153 _hb_ot_layout_get_glyph_property (hb_ot_layout_t *layout,
 154                                   hb_codepoint_t  glyph)
 155 {
 156   hb_ot_layout_class_t klass;
 157
 158   klass = layout->gdef->get_glyph_class (glyph);
 159
 160   if (!klass && glyph < layout->new_gdef.len)
 161     klass = layout->new_gdef.klasses[glyph];
 162
 163   switch (klass) {
 164   default:
 165   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 166   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 167   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 168   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 169   case GDEF::MarkGlyph:
 170         /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 171          * introduced without a version bump, so it may not be safe */
 172         klass = layout->gdef->get_mark_attachment_type (glyph);
 173         return HB_OT_LAYOUT_GLYPH_CLASS_MARK + (klass << 8);
 174   }
 175 }
 176
 177 HB_INTERNAL hb_bool_t
 178 _hb_ot_layout_check_glyph_property (hb_ot_layout_t  *layout,
 179                                     hb_glyph_info_t *ginfo,
 180                                     unsigned int     lookup_flags,
 181                                     unsigned int    *property_out)
 182 {
 183   unsigned int property;
 184
 185   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 186     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->gindex);
 187   property = ginfo->gproperty;
 188   if (property_out)
 189     *property_out = property;
 190
 191   /* Not covered, if, for example, glyph class is ligature and
 192    * lookup_flags includes LookupFlags::IgnoreLigatures
 193    */
 194   if (property & lookup_flags)
 195     return false;
 196
 197   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 198   {
 199     /* If using mark filtering sets, the high short of
 200      * lookup_flags has the set index.
 201      */
 202     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 203       return layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->gindex);
 204
 205     /* The second byte of lookup_flags has the meaning
 206      * "ignore marks of attachment type different than
 207      * the attachment type specified."
 208      */
 209     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 210       return (lookup_flags & LookupFlag::MarkAttachmentType) == (property & LookupFlag::MarkAttachmentType);
 211   }
 212
 213   return true;
 214 }
 215
 216 HB_INTERNAL hb_bool_t
 217 _hb_ot_layout_skip_mark (hb_ot_layout_t  *layout,
 218                          hb_glyph_info_t *ginfo,
 219                          unsigned int     lookup_flags,
 220                          unsigned int    *property_out)
 221 {
 222   unsigned int property;
 223
 224   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 225     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->gindex);
 226   property = ginfo->gproperty;
 227   if (property_out)
 228     *property_out = property;
 229
 230   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 231   {
 232     /* Skip mark if lookup_flags includes LookupFlags::IgnoreMarks */
 233     if (lookup_flags & LookupFlag::IgnoreMarks)
 234       return true;
 235
 236     /* If using mark filtering sets, the high short of lookup_flags has the set index. */
 237     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 238       return !layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->gindex);
 239
 240     /* The second byte of lookup_flags has the meaning "ignore marks of attachment type
 241      * different than the attachment type specified." */
 242     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 243       return (lookup_flags & LookupFlag::MarkAttachmentType) != (property & LookupFlag::MarkAttachmentType);
 244   }
 245
 246   return false;
 247 }
 248
 249 HB_INTERNAL void
 250 _hb_ot_layout_set_glyph_property (hb_ot_layout_t *layout,
 251                                   hb_codepoint_t  glyph,
 252                                   unsigned int    property)
 253 { hb_ot_layout_set_glyph_class (layout, glyph, (hb_ot_layout_glyph_class_t) (property & 0xff)); }
 254
 255
 256 hb_ot_layout_glyph_class_t
 257 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 258                               hb_codepoint_t  glyph)
 259 { return (hb_ot_layout_glyph_class_t) (_hb_ot_layout_get_glyph_property (layout, glyph) & 0xff); }
 260
 261 void
 262 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 263                               hb_codepoint_t              glyph,
 264                               hb_ot_layout_glyph_class_t  klass)
 265 {
 266   /* TODO optimize this, similar to old harfbuzz code for example */
 267
 268   hb_ot_layout_class_t gdef_klass;
 269   int len = layout->new_gdef.len;
 270
 271   if (HB_UNLIKELY (glyph > 65535))
 272     return;
 273
 274   if (glyph >= len) {
 275     int new_len;
 276     unsigned char *new_klasses;
 277
 278     new_len = len == 0 ? 120 : 2 * len;
 279     if (new_len > 65535)
 280       new_len = 65535;
 281     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 282
 283     if (HB_UNLIKELY (!new_klasses))
 284       return;
 285
 286     memset (new_klasses + len, 0, new_len - len);
 287
 288     layout->new_gdef.klasses = new_klasses;
 289     layout->new_gdef.len = new_len;
 290   }
 291
 292   switch (klass) {
 293   default:
 294   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 295   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 296   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 297   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 298   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 299   }
 300
 301   layout->new_gdef.klasses[glyph] = gdef_klass;
 302   return;
 303 }
 304
 305 void
 306 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 307                                   uint16_t        num_total_glyphs,
 308                                   hb_codepoint_t *glyphs,
 309                                   unsigned char  *klasses,
 310                                   uint16_t        count)
 311 {
 312   if (HB_UNLIKELY (!count || !glyphs || !klasses))
 313     return;
 314
 315   if (layout->new_gdef.len == 0) {
 316     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 317     layout->new_gdef.len = count;
 318   }
 319
 320   for (unsigned int i = 0; i < count; i++)
 321     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 322 }
 323
 324 hb_bool_t
 325 hb_ot_layout_get_attach_points (hb_ot_layout_t *layout,
 326                                 hb_codepoint_t  glyph,
 327                                 unsigned int   *point_count /* IN/OUT */,
 328                                 unsigned int   *point_array /* OUT */)
 329 {
 330   return layout->gdef->get_attach_points (glyph, point_count, point_array);
 331 }
 332
 333 hb_bool_t
 334 hb_ot_layout_get_lig_carets (hb_ot_layout_t *layout,
 335                              hb_codepoint_t  glyph,
 336                              unsigned int   *caret_count /* IN/OUT */,
 337                              int            *caret_array /* OUT */)
 338 {
 339   return layout->gdef->get_lig_carets (layout, glyph, caret_count, caret_array);
 340 }
 341
 342 /*
 343  * GSUB/GPOS
 344  */
 345
 346 static const GSUBGPOS&
 347 get_gsubgpos_table (hb_ot_layout_t            *layout,
 348                     hb_ot_layout_table_type_t  table_type)
 349 {
 350   switch (table_type) {
 351     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 352     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 353     default:                           return Null(GSUBGPOS);
 354   }
 355 }
 356
 357
 358 unsigned int
 359 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 360                                      hb_ot_layout_table_type_t  table_type)
 361 {
 362   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 363
 364   return g.get_script_count ();
 365 }
 366
 367 hb_tag_t
 368 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 369                                    hb_ot_layout_table_type_t  table_type,
 370                                    unsigned int               script_index)
 371 {
 372   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 373
 374   return g.get_script_tag (script_index);
 375 }
 376
 377 hb_bool_t
 378 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 379                                 hb_ot_layout_table_type_t  table_type,
 380                                 hb_tag_t                   script_tag,
 381                                 unsigned int              *script_index)
 382 {
 383   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 384   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 385
 386   if (g.find_script_index (script_tag, script_index))
 387     return TRUE;
 388
 389   /* try finding 'DFLT' */
 390   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 391     return FALSE;
 392
 393   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 394   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 395     return FALSE;
 396
 397   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 398   return FALSE;
 399 }
 400
 401 unsigned int
 402 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 403                                       hb_ot_layout_table_type_t  table_type)
 404 {
 405   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 406
 407   return g.get_feature_count ();
 408 }
 409
 410 hb_tag_t
 411 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 412                                     hb_ot_layout_table_type_t  table_type,
 413                                     unsigned int               feature_index)
 414 {
 415   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 416
 417   return g.get_feature_tag (feature_index);
 418 }
 419
 420 hb_bool_t
 421 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 422                                  hb_ot_layout_table_type_t  table_type,
 423                                  hb_tag_t                   feature_tag,
 424                                  unsigned int              *feature_index)
 425 {
 426   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 427   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 428
 429   if (g.find_feature_index (feature_tag, feature_index))
 430     return TRUE;
 431
 432   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 433   return FALSE;
 434 }
 435
 436 unsigned int
 437 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 438                                      hb_ot_layout_table_type_t  table_type)
 439 {
 440   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 441
 442   return g.get_lookup_count ();
 443 }
 444
 445
 446 unsigned int
 447 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 448                                         hb_ot_layout_table_type_t  table_type,
 449                                         unsigned int               script_index)
 450 {
 451   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 452
 453   return s.get_lang_sys_count ();
 454 }
 455
 456 hb_tag_t
 457 hb_ot_layout_script_get_language_tag (hb_ot_layout_t            *layout,
 458                                       hb_ot_layout_table_type_t  table_type,
 459                                       unsigned int               script_index,
 460                                       unsigned int               language_index)
 461 {
 462   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 463
 464   return s.get_lang_sys_tag (language_index);
 465 }
 466
 467 hb_bool_t
 468 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 469                                    hb_ot_layout_table_type_t  table_type,
 470                                    unsigned int               script_index,
 471                                    hb_tag_t                   language_tag,
 472                                    unsigned int              *language_index)
 473 {
 474   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 475   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 476
 477   if (s.find_lang_sys_index (language_tag, language_index))
 478     return TRUE;
 479
 480   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 481   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 482     return FALSE;
 483
 484   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 485   return FALSE;
 486 }
 487
 488 hb_bool_t
 489 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 490                                                   hb_ot_layout_table_type_t  table_type,
 491                                                   unsigned int               script_index,
 492                                                   unsigned int               language_index,
 493                                                   unsigned int              *feature_index)
 494 {
 495   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 496
 497   if (feature_index) *feature_index = l.get_required_feature_index ();
 498
 499   return l.has_required_feature ();
 500 }
 501
 502 unsigned int
 503 hb_ot_layout_language_get_feature_count (hb_ot_layout_t            *layout,
 504                                          hb_ot_layout_table_type_t  table_type,
 505                                          unsigned int               script_index,
 506                                          unsigned int               language_index)
 507 {
 508   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 509
 510   return l.get_feature_count ();
 511 }
 512
 513 unsigned int
 514 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 515                                          hb_ot_layout_table_type_t  table_type,
 516                                          unsigned int               script_index,
 517                                          unsigned int               language_index,
 518                                          unsigned int               num_feature)
 519 {
 520   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 521   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 522
 523   return l.get_feature_index (num_feature);
 524 }
 525
 526 hb_tag_t
 527 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 528                                        hb_ot_layout_table_type_t  table_type,
 529                                        unsigned int               script_index,
 530                                        unsigned int               language_index,
 531                                        unsigned int               num_feature)
 532 {
 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   unsigned int feature_index = l.get_feature_index (num_feature);
 536
 537   return g.get_feature_tag (feature_index);
 538 }
 539
 540
 541 hb_bool_t
 542 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 543                                     hb_ot_layout_table_type_t  table_type,
 544                                     unsigned int               script_index,
 545                                     unsigned int               language_index,
 546                                     hb_tag_t                   feature_tag,
 547                                     unsigned int              *feature_index)
 548 {
 549   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 550   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 551   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 552
 553   unsigned int num_features = l.get_feature_count ();
 554   for (unsigned int i = 0; i < num_features; i++) {
 555     unsigned int f_index = l.get_feature_index (i);
 556
 557     if (feature_tag == g.get_feature_tag (f_index)) {
 558       if (feature_index) *feature_index = f_index;
 559       return TRUE;
 560     }
 561   }
 562
 563   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 564   return FALSE;
 565 }
 566
 567 unsigned int
 568 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 569                                        hb_ot_layout_table_type_t  table_type,
 570                                        unsigned int               feature_index)
 571 {
 572   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 573   const Feature &f = g.get_feature (feature_index);
 574
 575   return f.get_lookup_count ();
 576 }
 577
 578 unsigned int
 579 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 580                                        hb_ot_layout_table_type_t  table_type,
 581                                        unsigned int               feature_index,
 582                                        unsigned int               num_lookup)
 583 {
 584   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 585   const Feature &f = g.get_feature (feature_index);
 586
 587   return f.get_lookup_index (num_lookup);
 588 }
 589
 590 /*
 591  * GSUB
 592  */
 593
 594 hb_bool_t
 595 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 596                                 hb_buffer_t                 *buffer,
 597                                 unsigned int                 lookup_index,
 598                                 hb_ot_layout_feature_mask_t  mask)
 599 {
 600   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 601 }
 602
 603 /*
 604  * GPOS
 605  */
 606
 607 hb_bool_t
 608 hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
 609                                 hb_buffer_t                 *buffer,
 610                                 unsigned int                 lookup_index,
 611                                 hb_ot_layout_feature_mask_t  mask)
 612 {
 613   return layout->gpos->position_lookup (layout, buffer, lookup_index, mask);
 614 }