hb-ot-layout.cc revision 568000274c8edb5f41bc4f876ce21fcc8bdaeed8
1/*
2 * Copyright © 1998-2004  David Turner and Werner Lemberg
3 * Copyright © 2006  Behdad Esfahbod
4 * Copyright © 2007,2008,2009  Red Hat, Inc.
5 * Copyright © 2012  Google, Inc.
6 *
7 *  This is part of HarfBuzz, a text shaping library.
8 *
9 * Permission is hereby granted, without written agreement and without
10 * license or royalty fees, to use, copy, modify, and distribute this
11 * software and its documentation for any purpose, provided that the
12 * above copyright notice and the following two paragraphs appear in
13 * all copies of this software.
14 *
15 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
16 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
17 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
18 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
19 * DAMAGE.
20 *
21 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
22 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
23 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
24 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
25 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
26 *
27 * Red Hat Author(s): Behdad Esfahbod
28 * Google Author(s): Behdad Esfahbod
29 */
30
31#include "hb-ot-layout-private.hh"
32
33#include "hb-ot-layout-gdef-table.hh"
34#include "hb-ot-layout-gsub-table.hh"
35#include "hb-ot-layout-gpos-table.hh"
36
37#include <stdlib.h>
38#include <string.h>
39
40
41HB_SHAPER_DATA_ENSURE_DECLARE(ot, face)
42
43hb_ot_layout_t *
44_hb_ot_layout_create (hb_face_t *face)
45{
46  hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
47  if (unlikely (!layout))
48    return NULL;
49
50  layout->gdef_blob = OT::Sanitizer<OT::GDEF>::sanitize (face->reference_table (HB_OT_TAG_GDEF));
51  layout->gdef = OT::Sanitizer<OT::GDEF>::lock_instance (layout->gdef_blob);
52
53  layout->gsub_blob = OT::Sanitizer<OT::GSUB>::sanitize (face->reference_table (HB_OT_TAG_GSUB));
54  layout->gsub = OT::Sanitizer<OT::GSUB>::lock_instance (layout->gsub_blob);
55
56  layout->gpos_blob = OT::Sanitizer<OT::GPOS>::sanitize (face->reference_table (HB_OT_TAG_GPOS));
57  layout->gpos = OT::Sanitizer<OT::GPOS>::lock_instance (layout->gpos_blob);
58
59  layout->gsub_lookup_count = layout->gsub->get_lookup_count ();
60  layout->gpos_lookup_count = layout->gpos->get_lookup_count ();
61
62  layout->gsub_digests = (hb_set_digest_t *) calloc (layout->gsub->get_lookup_count (), sizeof (hb_set_digest_t));
63  layout->gpos_digests = (hb_set_digest_t *) calloc (layout->gpos->get_lookup_count (), sizeof (hb_set_digest_t));
64
65  if (unlikely ((layout->gsub_lookup_count && !layout->gsub_digests) ||
66		(layout->gpos_lookup_count && !layout->gpos_digests)))
67  {
68    _hb_ot_layout_destroy (layout);
69    return NULL;
70  }
71
72  for (unsigned int i = 0; i < layout->gsub_lookup_count; i++)
73    layout->gsub->get_lookup (i).add_coverage (&layout->gsub_digests[i]);
74  for (unsigned int i = 0; i < layout->gpos_lookup_count; i++)
75    layout->gpos->get_lookup (i).add_coverage (&layout->gpos_digests[i]);
76
77  return layout;
78}
79
80void
81_hb_ot_layout_destroy (hb_ot_layout_t *layout)
82{
83  hb_blob_destroy (layout->gdef_blob);
84  hb_blob_destroy (layout->gsub_blob);
85  hb_blob_destroy (layout->gpos_blob);
86
87  free (layout->gsub_digests);
88  free (layout->gpos_digests);
89
90  free (layout);
91}
92
93static inline const OT::GDEF&
94_get_gdef (hb_face_t *face)
95{
96  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GDEF);
97  return *hb_ot_layout_from_face (face)->gdef;
98}
99static inline const OT::GSUB&
100_get_gsub (hb_face_t *face)
101{
102  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GSUB);
103  return *hb_ot_layout_from_face (face)->gsub;
104}
105static inline const OT::GPOS&
106_get_gpos (hb_face_t *face)
107{
108  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GPOS);
109  return *hb_ot_layout_from_face (face)->gpos;
110}
111
112
113/*
114 * GDEF
115 */
116
117hb_bool_t
118hb_ot_layout_has_glyph_classes (hb_face_t *face)
119{
120  return _get_gdef (face).has_glyph_classes ();
121}
122
123hb_ot_layout_glyph_class_t
124hb_ot_layout_get_glyph_class (hb_face_t      *face,
125			      hb_codepoint_t  glyph)
126{
127  return (hb_ot_layout_glyph_class_t) _get_gdef (face).get_glyph_class (glyph);
128}
129
130void
131hb_ot_layout_get_glyphs_in_class (hb_face_t                  *face,
132				  hb_ot_layout_glyph_class_t  klass,
133				  hb_set_t                   *glyphs /* OUT */)
134{
135  return _get_gdef (face).get_glyphs_in_class (klass, glyphs);
136}
137
138unsigned int
139hb_ot_layout_get_attach_points (hb_face_t      *face,
140				hb_codepoint_t  glyph,
141				unsigned int    start_offset,
142				unsigned int   *point_count /* IN/OUT */,
143				unsigned int   *point_array /* OUT */)
144{
145  return _get_gdef (face).get_attach_points (glyph, start_offset, point_count, point_array);
146}
147
148unsigned int
149hb_ot_layout_get_ligature_carets (hb_font_t      *font,
150				  hb_direction_t  direction,
151				  hb_codepoint_t  glyph,
152				  unsigned int    start_offset,
153				  unsigned int   *caret_count /* IN/OUT */,
154				  int            *caret_array /* OUT */)
155{
156  return _get_gdef (font->face).get_lig_carets (font, direction, glyph, start_offset, caret_count, caret_array);
157}
158
159
160/*
161 * GSUB/GPOS
162 */
163
164static const OT::GSUBGPOS&
165get_gsubgpos_table (hb_face_t *face,
166		    hb_tag_t   table_tag)
167{
168  switch (table_tag) {
169    case HB_OT_TAG_GSUB: return _get_gsub (face);
170    case HB_OT_TAG_GPOS: return _get_gpos (face);
171    default:             return OT::Null(OT::GSUBGPOS);
172  }
173}
174
175
176unsigned int
177hb_ot_layout_table_get_script_tags (hb_face_t    *face,
178				    hb_tag_t      table_tag,
179				    unsigned int  start_offset,
180				    unsigned int *script_count /* IN/OUT */,
181				    hb_tag_t     *script_tags /* OUT */)
182{
183  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
184
185  return g.get_script_tags (start_offset, script_count, script_tags);
186}
187
188#define HB_OT_TAG_LATIN_SCRIPT		HB_TAG ('l', 'a', 't', 'n')
189
190hb_bool_t
191hb_ot_layout_table_find_script (hb_face_t    *face,
192				hb_tag_t      table_tag,
193				hb_tag_t      script_tag,
194				unsigned int *script_index)
195{
196  ASSERT_STATIC (OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
197  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
198
199  if (g.find_script_index (script_tag, script_index))
200    return true;
201
202  /* try finding 'DFLT' */
203  if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index))
204    return false;
205
206  /* try with 'dflt'; MS site has had typos and many fonts use it now :(.
207   * including many versions of DejaVu Sans Mono! */
208  if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index))
209    return false;
210
211  /* try with 'latn'; some old fonts put their features there even though
212     they're really trying to support Thai, for example :( */
213  if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index))
214    return false;
215
216  if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
217  return false;
218}
219
220hb_bool_t
221hb_ot_layout_table_choose_script (hb_face_t      *face,
222				  hb_tag_t        table_tag,
223				  const hb_tag_t *script_tags,
224				  unsigned int   *script_index,
225				  hb_tag_t       *chosen_script)
226{
227  ASSERT_STATIC (OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
228  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
229
230  while (*script_tags)
231  {
232    if (g.find_script_index (*script_tags, script_index)) {
233      if (chosen_script)
234        *chosen_script = *script_tags;
235      return true;
236    }
237    script_tags++;
238  }
239
240  /* try finding 'DFLT' */
241  if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index)) {
242    if (chosen_script)
243      *chosen_script = HB_OT_TAG_DEFAULT_SCRIPT;
244    return false;
245  }
246
247  /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
248  if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index)) {
249    if (chosen_script)
250      *chosen_script = HB_OT_TAG_DEFAULT_LANGUAGE;
251    return false;
252  }
253
254  /* try with 'latn'; some old fonts put their features there even though
255     they're really trying to support Thai, for example :( */
256  if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index)) {
257    if (chosen_script)
258      *chosen_script = HB_OT_TAG_LATIN_SCRIPT;
259    return false;
260  }
261
262  if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
263  if (chosen_script)
264    *chosen_script = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
265  return false;
266}
267
268unsigned int
269hb_ot_layout_table_get_feature_tags (hb_face_t    *face,
270				     hb_tag_t      table_tag,
271				     unsigned int  start_offset,
272				     unsigned int *feature_count /* IN/OUT */,
273				     hb_tag_t     *feature_tags /* OUT */)
274{
275  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
276
277  return g.get_feature_tags (start_offset, feature_count, feature_tags);
278}
279
280
281unsigned int
282hb_ot_layout_script_get_language_tags (hb_face_t    *face,
283				       hb_tag_t      table_tag,
284				       unsigned int  script_index,
285				       unsigned int  start_offset,
286				       unsigned int *language_count /* IN/OUT */,
287				       hb_tag_t     *language_tags /* OUT */)
288{
289  const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
290
291  return s.get_lang_sys_tags (start_offset, language_count, language_tags);
292}
293
294hb_bool_t
295hb_ot_layout_script_find_language (hb_face_t    *face,
296				   hb_tag_t      table_tag,
297				   unsigned int  script_index,
298				   hb_tag_t      language_tag,
299				   unsigned int *language_index)
300{
301  ASSERT_STATIC (OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
302  const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
303
304  if (s.find_lang_sys_index (language_tag, language_index))
305    return true;
306
307  /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
308  if (s.find_lang_sys_index (HB_OT_TAG_DEFAULT_LANGUAGE, language_index))
309    return false;
310
311  if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
312  return false;
313}
314
315hb_bool_t
316hb_ot_layout_language_get_required_feature_index (hb_face_t    *face,
317						  hb_tag_t      table_tag,
318						  unsigned int  script_index,
319						  unsigned int  language_index,
320						  unsigned int *feature_index)
321{
322  const OT::LangSys &l = get_gsubgpos_table (face, table_tag).get_script (script_index).get_lang_sys (language_index);
323
324  if (feature_index) *feature_index = l.get_required_feature_index ();
325
326  return l.has_required_feature ();
327}
328
329unsigned int
330hb_ot_layout_language_get_feature_indexes (hb_face_t    *face,
331					   hb_tag_t      table_tag,
332					   unsigned int  script_index,
333					   unsigned int  language_index,
334					   unsigned int  start_offset,
335					   unsigned int *feature_count /* IN/OUT */,
336					   unsigned int *feature_indexes /* OUT */)
337{
338  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
339  const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
340
341  return l.get_feature_indexes (start_offset, feature_count, feature_indexes);
342}
343
344unsigned int
345hb_ot_layout_language_get_feature_tags (hb_face_t    *face,
346					hb_tag_t      table_tag,
347					unsigned int  script_index,
348					unsigned int  language_index,
349					unsigned int  start_offset,
350					unsigned int *feature_count /* IN/OUT */,
351					hb_tag_t     *feature_tags /* OUT */)
352{
353  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
354  const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
355
356  ASSERT_STATIC (sizeof (unsigned int) == sizeof (hb_tag_t));
357  unsigned int ret = l.get_feature_indexes (start_offset, feature_count, (unsigned int *) feature_tags);
358
359  if (feature_tags) {
360    unsigned int count = *feature_count;
361    for (unsigned int i = 0; i < count; i++)
362      feature_tags[i] = g.get_feature_tag ((unsigned int) feature_tags[i]);
363  }
364
365  return ret;
366}
367
368
369hb_bool_t
370hb_ot_layout_language_find_feature (hb_face_t    *face,
371				    hb_tag_t      table_tag,
372				    unsigned int  script_index,
373				    unsigned int  language_index,
374				    hb_tag_t      feature_tag,
375				    unsigned int *feature_index)
376{
377  ASSERT_STATIC (OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
378  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
379  const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
380
381  unsigned int num_features = l.get_feature_count ();
382  for (unsigned int i = 0; i < num_features; i++) {
383    unsigned int f_index = l.get_feature_index (i);
384
385    if (feature_tag == g.get_feature_tag (f_index)) {
386      if (feature_index) *feature_index = f_index;
387      return true;
388    }
389  }
390
391  if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
392  return false;
393}
394
395unsigned int
396hb_ot_layout_feature_get_lookups (hb_face_t    *face,
397				  hb_tag_t      table_tag,
398				  unsigned int  feature_index,
399				  unsigned int  start_offset,
400				  unsigned int *lookup_count /* IN/OUT */,
401				  unsigned int *lookup_indexes /* OUT */)
402{
403  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
404  const OT::Feature &f = g.get_feature (feature_index);
405
406  return f.get_lookup_indexes (start_offset, lookup_count, lookup_indexes);
407}
408
409static void
410_hb_ot_layout_collect_lookups_lookups (hb_face_t      *face,
411				       hb_tag_t        table_tag,
412				       unsigned int    feature_index,
413				       hb_set_t       *lookup_indexes /* OUT */)
414{
415  unsigned int lookup_indices[32];
416  unsigned int offset, len;
417
418  offset = 0;
419  do {
420    len = ARRAY_LENGTH (lookup_indices);
421    hb_ot_layout_feature_get_lookups (face,
422				      table_tag,
423				      feature_index,
424				      offset, &len,
425				      lookup_indices);
426
427    for (unsigned int i = 0; i < len; i++)
428      lookup_indexes->add (lookup_indices[i]);
429
430    offset += len;
431  } while (len == ARRAY_LENGTH (lookup_indices));
432}
433
434static void
435_hb_ot_layout_collect_lookups_features (hb_face_t      *face,
436					hb_tag_t        table_tag,
437					unsigned int    script_index,
438					unsigned int    language_index,
439					const hb_tag_t *features,
440					hb_set_t       *lookup_indexes /* OUT */)
441{
442  unsigned int required_feature_index;
443  if (hb_ot_layout_language_get_required_feature_index (face,
444							table_tag,
445							script_index,
446							language_index,
447							&required_feature_index))
448    _hb_ot_layout_collect_lookups_lookups (face,
449					   table_tag,
450					   required_feature_index,
451					   lookup_indexes);
452
453  if (!features)
454  {
455    /* All features */
456    unsigned int feature_indices[32];
457    unsigned int offset, len;
458
459    offset = 0;
460    do {
461      len = ARRAY_LENGTH (feature_indices);
462      hb_ot_layout_language_get_feature_indexes (face,
463						 table_tag,
464						 script_index,
465						 language_index,
466						 offset, &len,
467						 feature_indices);
468
469      for (unsigned int i = 0; i < len; i++)
470	_hb_ot_layout_collect_lookups_lookups (face,
471					       table_tag,
472					       feature_indices[i],
473					       lookup_indexes);
474
475      offset += len;
476    } while (len == ARRAY_LENGTH (feature_indices));
477  }
478  else
479  {
480    for (; *features; features++)
481    {
482      unsigned int feature_index;
483      if (hb_ot_layout_language_find_feature (face,
484					      table_tag,
485					      script_index,
486					      language_index,
487					      *features,
488					      &feature_index))
489        _hb_ot_layout_collect_lookups_lookups (face,
490					       table_tag,
491					       feature_index,
492					       lookup_indexes);
493    }
494  }
495}
496
497static void
498_hb_ot_layout_collect_lookups_languages (hb_face_t      *face,
499					 hb_tag_t        table_tag,
500					 unsigned int    script_index,
501					 const hb_tag_t *languages,
502					 const hb_tag_t *features,
503					 hb_set_t       *lookup_indexes /* OUT */)
504{
505  _hb_ot_layout_collect_lookups_features (face,
506					  table_tag,
507					  script_index,
508					  HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX,
509					  features,
510					  lookup_indexes);
511
512  if (!languages)
513  {
514    /* All languages */
515    unsigned int count = hb_ot_layout_script_get_language_tags (face,
516								table_tag,
517								script_index,
518								0, NULL, NULL);
519    for (unsigned int language_index = 0; language_index < count; language_index++)
520      _hb_ot_layout_collect_lookups_features (face,
521					      table_tag,
522					      script_index,
523					      language_index,
524					      features,
525					      lookup_indexes);
526  }
527  else
528  {
529    for (; *languages; languages++)
530    {
531      unsigned int language_index;
532      if (hb_ot_layout_script_find_language (face,
533					     table_tag,
534					     script_index,
535					     *languages,
536					     &language_index))
537        _hb_ot_layout_collect_lookups_features (face,
538						table_tag,
539						script_index,
540						language_index,
541						features,
542						lookup_indexes);
543    }
544  }
545}
546
547void
548hb_ot_layout_collect_lookups (hb_face_t      *face,
549			      hb_tag_t        table_tag,
550			      const hb_tag_t *scripts,
551			      const hb_tag_t *languages,
552			      const hb_tag_t *features,
553			      hb_set_t       *lookup_indexes /* OUT */)
554{
555  if (!scripts)
556  {
557    /* All scripts */
558    unsigned int count = hb_ot_layout_table_get_script_tags (face,
559							     table_tag,
560							     0, NULL, NULL);
561    for (unsigned int script_index = 0; script_index < count; script_index++)
562      _hb_ot_layout_collect_lookups_languages (face,
563					       table_tag,
564					       script_index,
565					       languages,
566					       features,
567					       lookup_indexes);
568  }
569  else
570  {
571    for (; *scripts; scripts++)
572    {
573      unsigned int script_index;
574      if (hb_ot_layout_table_find_script (face,
575					  table_tag,
576					  *scripts,
577					  &script_index))
578        _hb_ot_layout_collect_lookups_languages (face,
579						 table_tag,
580						 script_index,
581						 languages,
582						 features,
583						 lookup_indexes);
584    }
585  }
586}
587
588void
589hb_ot_layout_lookup_collect_glyphs (hb_face_t    *face,
590				    hb_tag_t      table_tag,
591				    unsigned int  lookup_index,
592				    hb_set_t     *glyphs_before, /* OUT. May be NULL */
593				    hb_set_t     *glyphs_input,  /* OUT. May be NULL */
594				    hb_set_t     *glyphs_after,  /* OUT. May be NULL */
595				    hb_set_t     *glyphs_output  /* OUT. May be NULL */)
596{
597  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return;
598
599  OT::hb_collect_glyphs_context_t c (face,
600				     glyphs_before,
601				     glyphs_input,
602				     glyphs_after,
603				     glyphs_output);
604
605  switch (table_tag)
606  {
607    case HB_OT_TAG_GSUB:
608    {
609      const OT::SubstLookup& l = hb_ot_layout_from_face (face)->gsub->get_lookup (lookup_index);
610      l.collect_glyphs_lookup (&c);
611      return;
612    }
613    case HB_OT_TAG_GPOS:
614    {
615      const OT::PosLookup& l = hb_ot_layout_from_face (face)->gpos->get_lookup (lookup_index);
616      l.collect_glyphs_lookup (&c);
617      return;
618    }
619  }
620}
621
622
623/*
624 * OT::GSUB
625 */
626
627hb_bool_t
628hb_ot_layout_has_substitution (hb_face_t *face)
629{
630  return &_get_gsub (face) != &OT::Null(OT::GSUB);
631}
632
633hb_bool_t
634hb_ot_layout_lookup_would_substitute (hb_face_t            *face,
635				      unsigned int          lookup_index,
636				      const hb_codepoint_t *glyphs,
637				      unsigned int          glyphs_length,
638				      hb_bool_t             zero_context)
639{
640  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return false;
641  return hb_ot_layout_lookup_would_substitute_fast (face, lookup_index, glyphs, glyphs_length, zero_context);
642}
643
644hb_bool_t
645hb_ot_layout_lookup_would_substitute_fast (hb_face_t            *face,
646					   unsigned int          lookup_index,
647					   const hb_codepoint_t *glyphs,
648					   unsigned int          glyphs_length,
649					   hb_bool_t             zero_context)
650{
651  if (unlikely (lookup_index >= hb_ot_layout_from_face (face)->gsub_lookup_count)) return false;
652  OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, zero_context);
653
654  const OT::SubstLookup& l = hb_ot_layout_from_face (face)->gsub->get_lookup (lookup_index);
655
656  return l.would_apply (&c, &hb_ot_layout_from_face (face)->gsub_digests[lookup_index]);
657}
658
659void
660hb_ot_layout_substitute_start (hb_font_t *font, hb_buffer_t *buffer)
661{
662  OT::GSUB::substitute_start (font, buffer);
663}
664
665hb_bool_t
666hb_ot_layout_substitute_lookup (hb_font_t    *font,
667				hb_buffer_t  *buffer,
668				unsigned int  lookup_index,
669				hb_mask_t     mask)
670{
671  if (unlikely (lookup_index >= hb_ot_layout_from_face (font->face)->gsub_lookup_count)) return false;
672
673  OT::hb_apply_context_t c (font, buffer, mask);
674
675  const OT::SubstLookup& l = hb_ot_layout_from_face (font->face)->gsub->get_lookup (lookup_index);
676
677  return l.apply_string (&c, &hb_ot_layout_from_face (font->face)->gsub_digests[lookup_index]);
678}
679
680void
681hb_ot_layout_substitute_finish (hb_font_t *font, hb_buffer_t *buffer)
682{
683  OT::GSUB::substitute_finish (font, buffer);
684}
685
686void
687hb_ot_layout_lookup_substitute_closure (hb_face_t    *face,
688				        unsigned int  lookup_index,
689				        hb_set_t     *glyphs)
690{
691  OT::hb_closure_context_t c (face, glyphs);
692
693  const OT::SubstLookup& l = _get_gsub (face).get_lookup (lookup_index);
694
695  l.closure (&c);
696}
697
698/*
699 * OT::GPOS
700 */
701
702hb_bool_t
703hb_ot_layout_has_positioning (hb_face_t *face)
704{
705  return &_get_gpos (face) != &OT::Null(OT::GPOS);
706}
707
708void
709hb_ot_layout_position_start (hb_font_t *font, hb_buffer_t *buffer)
710{
711  OT::GPOS::position_start (font, buffer);
712}
713
714hb_bool_t
715hb_ot_layout_position_lookup (hb_font_t    *font,
716			      hb_buffer_t  *buffer,
717			      unsigned int  lookup_index,
718			      hb_mask_t     mask)
719{
720  if (unlikely (lookup_index >= hb_ot_layout_from_face (font->face)->gpos_lookup_count)) return false;
721
722  OT::hb_apply_context_t c (font, buffer, mask);
723
724  const OT::PosLookup& l = hb_ot_layout_from_face (font->face)->gpos->get_lookup (lookup_index);
725
726  return l.apply_string (&c, &hb_ot_layout_from_face (font->face)->gpos_digests[lookup_index]);
727}
728
729void
730hb_ot_layout_position_finish (hb_font_t *font, hb_buffer_t *buffer)
731{
732  OT::GPOS::position_finish (font, buffer);
733}
734
735hb_bool_t
736hb_ot_layout_get_size_params (hb_face_t    *face,
737			      unsigned int *design_size,       /* OUT.  May be NULL */
738			      unsigned int *subfamily_id,      /* OUT.  May be NULL */
739			      unsigned int *subfamily_name_id, /* OUT.  May be NULL */
740			      unsigned int *range_start,       /* OUT.  May be NULL */
741			      unsigned int *range_end          /* OUT.  May be NULL */)
742{
743  const OT::GPOS &gpos = _get_gpos (face);
744  const hb_tag_t tag = HB_TAG ('s','i','z','e');
745
746  unsigned int num_features = gpos.get_feature_count ();
747  for (unsigned int i = 0; i < num_features; i++)
748  {
749    if (tag == gpos.get_feature_tag (i))
750    {
751      const OT::Feature &f = gpos.get_feature (i);
752      const OT::FeatureParamsSize &params = f.get_feature_params ().get_size_params (tag);
753
754      if (params.designSize)
755      {
756#define PARAM(a, A) if (a) *a = params.A
757	PARAM (design_size, designSize);
758	PARAM (subfamily_id, subfamilyID);
759	PARAM (subfamily_name_id, subfamilyNameID);
760	PARAM (range_start, rangeStart);
761	PARAM (range_end, rangeEnd);
762#undef PARAM
763
764	return true;
765      }
766    }
767  }
768
769#define PARAM(a, A) if (a) *a = 0
770  PARAM (design_size, designSize);
771  PARAM (subfamily_id, subfamilyID);
772  PARAM (subfamily_name_id, subfamilyNameID);
773  PARAM (range_start, rangeStart);
774  PARAM (range_end, rangeEnd);
775#undef PARAM
776
777  return false;
778}
779