xref: /aosp_15_r20/external/harfbuzz_ng/src/hb-ot-layout.h (revision 2d1272b857b1f7575e6e246373e1cb218663db8a)
1 /*
2  * Copyright © 2007,2008,2009  Red Hat, Inc.
3  *
4  *  This is part of HarfBuzz, a text shaping library.
5  *
6  * Permission is hereby granted, without written agreement and without
7  * license or royalty fees, to use, copy, modify, and distribute this
8  * software and its documentation for any purpose, provided that the
9  * above copyright notice and the following two paragraphs appear in
10  * all copies of this software.
11  *
12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16  * DAMAGE.
17  *
18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23  *
24  * Red Hat Author(s): Behdad Esfahbod
25  */
26 
27 #if !defined(HB_OT_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
28 #error "Include <hb-ot.h> instead."
29 #endif
30 
31 #ifndef HB_OT_LAYOUT_H
32 #define HB_OT_LAYOUT_H
33 
34 #include "hb.h"
35 
36 #include "hb-ot-name.h"
37 
38 HB_BEGIN_DECLS
39 
40 
41 /**
42  * HB_OT_TAG_BASE:
43  *
44  * OpenType [Baseline Table](https://docs.microsoft.com/en-us/typography/opentype/spec/base).
45  */
46 #define HB_OT_TAG_BASE HB_TAG('B','A','S','E')
47 /**
48  * HB_OT_TAG_GDEF:
49  *
50  * OpenType [Glyph Definition Table](https://docs.microsoft.com/en-us/typography/opentype/spec/gdef).
51  */
52 #define HB_OT_TAG_GDEF HB_TAG('G','D','E','F')
53 /**
54  * HB_OT_TAG_GSUB:
55  *
56  * OpenType [Glyph Substitution Table](https://docs.microsoft.com/en-us/typography/opentype/spec/gsub).
57  */
58 #define HB_OT_TAG_GSUB HB_TAG('G','S','U','B')
59 /**
60  * HB_OT_TAG_GPOS:
61  *
62  * OpenType [Glyph Positioning Table](https://docs.microsoft.com/en-us/typography/opentype/spec/gpos).
63  */
64 #define HB_OT_TAG_GPOS HB_TAG('G','P','O','S')
65 /**
66  * HB_OT_TAG_JSTF:
67  *
68  * OpenType [Justification Table](https://docs.microsoft.com/en-us/typography/opentype/spec/jstf).
69  */
70 #define HB_OT_TAG_JSTF HB_TAG('J','S','T','F')
71 
72 
73 /*
74  * Script & Language tags.
75  */
76 
77 /**
78  * HB_OT_TAG_DEFAULT_SCRIPT:
79  *
80  * OpenType script tag, `DFLT`, for features that are not script-specific.
81  *
82  */
83 #define HB_OT_TAG_DEFAULT_SCRIPT	HB_TAG ('D', 'F', 'L', 'T')
84 /**
85  * HB_OT_TAG_DEFAULT_LANGUAGE:
86  *
87  * OpenType language tag, `dflt`. Not a valid language tag, but some fonts
88  * mistakenly use it.
89  */
90 #define HB_OT_TAG_DEFAULT_LANGUAGE	HB_TAG ('d', 'f', 'l', 't')
91 
92 /**
93  * HB_OT_MAX_TAGS_PER_SCRIPT:
94  *
95  * Maximum number of OpenType tags that can correspond to a give #hb_script_t.
96  *
97  * Since: 2.0.0
98  **/
99 #define HB_OT_MAX_TAGS_PER_SCRIPT	3u
100 /**
101  * HB_OT_MAX_TAGS_PER_LANGUAGE:
102  *
103  * Maximum number of OpenType tags that can correspond to a give #hb_language_t.
104  *
105  * Since: 2.0.0
106  **/
107 #define HB_OT_MAX_TAGS_PER_LANGUAGE	3u
108 
109 HB_EXTERN void
110 hb_ot_tags_from_script_and_language (hb_script_t   script,
111 				     hb_language_t language,
112 				     unsigned int *script_count /* IN/OUT */,
113 				     hb_tag_t     *script_tags /* OUT */,
114 				     unsigned int *language_count /* IN/OUT */,
115 				     hb_tag_t     *language_tags /* OUT */);
116 
117 HB_EXTERN hb_script_t
118 hb_ot_tag_to_script (hb_tag_t tag);
119 
120 HB_EXTERN hb_language_t
121 hb_ot_tag_to_language (hb_tag_t tag);
122 
123 HB_EXTERN void
124 hb_ot_tags_to_script_and_language (hb_tag_t       script_tag,
125 				   hb_tag_t       language_tag,
126 				   hb_script_t   *script /* OUT */,
127 				   hb_language_t *language /* OUT */);
128 
129 
130 /*
131  * GDEF
132  */
133 
134 HB_EXTERN hb_bool_t
135 hb_ot_layout_has_glyph_classes (hb_face_t *face);
136 
137 /**
138  * hb_ot_layout_glyph_class_t:
139  * @HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED: Glyphs not matching the other classifications
140  * @HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH: Spacing, single characters, capable of accepting marks
141  * @HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE: Glyphs that represent ligation of multiple characters
142  * @HB_OT_LAYOUT_GLYPH_CLASS_MARK: Non-spacing, combining glyphs that represent marks
143  * @HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT: Spacing glyphs that represent part of a single character
144  *
145  * The GDEF classes defined for glyphs.
146  *
147  **/
148 typedef enum {
149   HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED	= 0,
150   HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH	= 1,
151   HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE	= 2,
152   HB_OT_LAYOUT_GLYPH_CLASS_MARK		= 3,
153   HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT	= 4
154 } hb_ot_layout_glyph_class_t;
155 
156 HB_EXTERN hb_ot_layout_glyph_class_t
157 hb_ot_layout_get_glyph_class (hb_face_t      *face,
158 			      hb_codepoint_t  glyph);
159 
160 HB_EXTERN void
161 hb_ot_layout_get_glyphs_in_class (hb_face_t                  *face,
162 				  hb_ot_layout_glyph_class_t  klass,
163 				  hb_set_t                   *glyphs /* OUT */);
164 
165 /* Not that useful.  Provides list of attach points for a glyph that a
166  * client may want to cache */
167 HB_EXTERN unsigned int
168 hb_ot_layout_get_attach_points (hb_face_t      *face,
169 				hb_codepoint_t  glyph,
170 				unsigned int    start_offset,
171 				unsigned int   *point_count /* IN/OUT */,
172 				unsigned int   *point_array /* OUT */);
173 
174 /* Ligature caret positions */
175 HB_EXTERN unsigned int
176 hb_ot_layout_get_ligature_carets (hb_font_t      *font,
177 				  hb_direction_t  direction,
178 				  hb_codepoint_t  glyph,
179 				  unsigned int    start_offset,
180 				  unsigned int   *caret_count /* IN/OUT */,
181 				  hb_position_t  *caret_array /* OUT */);
182 
183 
184 /*
185  * GSUB/GPOS feature query and enumeration interface
186  */
187 
188 /**
189  * HB_OT_LAYOUT_NO_SCRIPT_INDEX:
190  *
191  * Special value for script index indicating unsupported script.
192  */
193 #define HB_OT_LAYOUT_NO_SCRIPT_INDEX		0xFFFFu
194 /**
195  * HB_OT_LAYOUT_NO_FEATURE_INDEX:
196  *
197  * Special value for feature index indicating unsupported feature.
198  */
199 #define HB_OT_LAYOUT_NO_FEATURE_INDEX		0xFFFFu
200 /**
201  * HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX:
202  *
203  * Special value for language index indicating default or unsupported language.
204  */
205 #define HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX	0xFFFFu
206 /**
207  * HB_OT_LAYOUT_NO_VARIATIONS_INDEX:
208  *
209  * Special value for variations index indicating unsupported variation.
210  */
211 #define HB_OT_LAYOUT_NO_VARIATIONS_INDEX	0xFFFFFFFFu
212 
213 HB_EXTERN unsigned int
214 hb_ot_layout_table_get_script_tags (hb_face_t    *face,
215 				    hb_tag_t      table_tag,
216 				    unsigned int  start_offset,
217 				    unsigned int *script_count /* IN/OUT */,
218 				    hb_tag_t     *script_tags /* OUT */);
219 
220 HB_EXTERN hb_bool_t
221 hb_ot_layout_table_find_script (hb_face_t    *face,
222 				hb_tag_t      table_tag,
223 				hb_tag_t      script_tag,
224 				unsigned int *script_index /* OUT */);
225 
226 HB_EXTERN hb_bool_t
227 hb_ot_layout_table_select_script (hb_face_t      *face,
228 				  hb_tag_t        table_tag,
229 				  unsigned int    script_count,
230 				  const hb_tag_t *script_tags,
231 				  unsigned int   *script_index /* OUT */,
232 				  hb_tag_t       *chosen_script /* OUT */);
233 
234 HB_EXTERN unsigned int
235 hb_ot_layout_table_get_feature_tags (hb_face_t    *face,
236 				     hb_tag_t      table_tag,
237 				     unsigned int  start_offset,
238 				     unsigned int *feature_count /* IN/OUT */,
239 				     hb_tag_t     *feature_tags /* OUT */);
240 
241 HB_EXTERN unsigned int
242 hb_ot_layout_script_get_language_tags (hb_face_t    *face,
243 				       hb_tag_t      table_tag,
244 				       unsigned int  script_index,
245 				       unsigned int  start_offset,
246 				       unsigned int *language_count /* IN/OUT */,
247 				       hb_tag_t     *language_tags /* OUT */);
248 
249 HB_EXTERN hb_bool_t
250 hb_ot_layout_script_select_language (hb_face_t      *face,
251 				     hb_tag_t        table_tag,
252 				     unsigned int    script_index,
253 				     unsigned int    language_count,
254 				     const hb_tag_t *language_tags,
255 				     unsigned int   *language_index /* OUT */);
256 
257 HB_EXTERN hb_bool_t
258 hb_ot_layout_script_select_language2 (hb_face_t      *face,
259 				     hb_tag_t        table_tag,
260 				     unsigned int    script_index,
261 				     unsigned int    language_count,
262 				     const hb_tag_t *language_tags,
263 				     unsigned int   *language_index /* OUT */,
264 				     hb_tag_t       *chosen_language /* OUT */);
265 
266 HB_EXTERN hb_bool_t
267 hb_ot_layout_language_get_required_feature_index (hb_face_t    *face,
268 						  hb_tag_t      table_tag,
269 						  unsigned int  script_index,
270 						  unsigned int  language_index,
271 						  unsigned int *feature_index /* OUT */);
272 
273 HB_EXTERN hb_bool_t
274 hb_ot_layout_language_get_required_feature (hb_face_t    *face,
275 					    hb_tag_t      table_tag,
276 					    unsigned int  script_index,
277 					    unsigned int  language_index,
278 					    unsigned int *feature_index /* OUT */,
279 					    hb_tag_t     *feature_tag /* OUT */);
280 
281 HB_EXTERN unsigned int
282 hb_ot_layout_language_get_feature_indexes (hb_face_t    *face,
283 					   hb_tag_t      table_tag,
284 					   unsigned int  script_index,
285 					   unsigned int  language_index,
286 					   unsigned int  start_offset,
287 					   unsigned int *feature_count /* IN/OUT */,
288 					   unsigned int *feature_indexes /* OUT */);
289 
290 HB_EXTERN unsigned int
291 hb_ot_layout_language_get_feature_tags (hb_face_t    *face,
292 					hb_tag_t      table_tag,
293 					unsigned int  script_index,
294 					unsigned int  language_index,
295 					unsigned int  start_offset,
296 					unsigned int *feature_count /* IN/OUT */,
297 					hb_tag_t     *feature_tags /* OUT */);
298 
299 HB_EXTERN hb_bool_t
300 hb_ot_layout_language_find_feature (hb_face_t    *face,
301 				    hb_tag_t      table_tag,
302 				    unsigned int  script_index,
303 				    unsigned int  language_index,
304 				    hb_tag_t      feature_tag,
305 				    unsigned int *feature_index /* OUT */);
306 
307 HB_EXTERN unsigned int
308 hb_ot_layout_feature_get_lookups (hb_face_t    *face,
309 				  hb_tag_t      table_tag,
310 				  unsigned int  feature_index,
311 				  unsigned int  start_offset,
312 				  unsigned int *lookup_count /* IN/OUT */,
313 				  unsigned int *lookup_indexes /* OUT */);
314 
315 HB_EXTERN unsigned int
316 hb_ot_layout_table_get_lookup_count (hb_face_t    *face,
317 				     hb_tag_t      table_tag);
318 
319 HB_EXTERN void
320 hb_ot_layout_collect_features (hb_face_t      *face,
321 			       hb_tag_t        table_tag,
322 			       const hb_tag_t *scripts,
323 			       const hb_tag_t *languages,
324 			       const hb_tag_t *features,
325 			       hb_set_t       *feature_indexes /* OUT */);
326 
327 HB_EXTERN void
328 hb_ot_layout_collect_features_map (hb_face_t      *face,
329 				   hb_tag_t        table_tag,
330 				   unsigned        script_index,
331 				   unsigned        language_index,
332 				   hb_map_t       *feature_map /* OUT */);
333 
334 HB_EXTERN void
335 hb_ot_layout_collect_lookups (hb_face_t      *face,
336 			      hb_tag_t        table_tag,
337 			      const hb_tag_t *scripts,
338 			      const hb_tag_t *languages,
339 			      const hb_tag_t *features,
340 			      hb_set_t       *lookup_indexes /* OUT */);
341 
342 HB_EXTERN void
343 hb_ot_layout_lookup_collect_glyphs (hb_face_t    *face,
344 				    hb_tag_t      table_tag,
345 				    unsigned int  lookup_index,
346 				    hb_set_t     *glyphs_before, /* OUT.  May be NULL */
347 				    hb_set_t     *glyphs_input,  /* OUT.  May be NULL */
348 				    hb_set_t     *glyphs_after,  /* OUT.  May be NULL */
349 				    hb_set_t     *glyphs_output  /* OUT.  May be NULL */);
350 
351 
352 /* Variations support */
353 
354 HB_EXTERN hb_bool_t
355 hb_ot_layout_table_find_feature_variations (hb_face_t    *face,
356 					    hb_tag_t      table_tag,
357 					    const int    *coords,
358 					    unsigned int  num_coords,
359 					    unsigned int *variations_index /* out */);
360 
361 HB_EXTERN unsigned int
362 hb_ot_layout_feature_with_variations_get_lookups (hb_face_t    *face,
363 						  hb_tag_t      table_tag,
364 						  unsigned int  feature_index,
365 						  unsigned int  variations_index,
366 						  unsigned int  start_offset,
367 						  unsigned int *lookup_count /* IN/OUT */,
368 						  unsigned int *lookup_indexes /* OUT */);
369 
370 
371 /*
372  * GSUB
373  */
374 
375 HB_EXTERN hb_bool_t
376 hb_ot_layout_has_substitution (hb_face_t *face);
377 
378 HB_EXTERN unsigned
379 hb_ot_layout_lookup_get_glyph_alternates (hb_face_t      *face,
380 					  unsigned        lookup_index,
381 					  hb_codepoint_t  glyph,
382 					  unsigned        start_offset,
383 					  unsigned       *alternate_count /* IN/OUT */,
384 					  hb_codepoint_t *alternate_glyphs /* OUT */);
385 
386 HB_EXTERN hb_bool_t
387 hb_ot_layout_lookup_would_substitute (hb_face_t            *face,
388 				      unsigned int          lookup_index,
389 				      const hb_codepoint_t *glyphs,
390 				      unsigned int          glyphs_length,
391 				      hb_bool_t             zero_context);
392 
393 HB_EXTERN void
394 hb_ot_layout_lookup_substitute_closure (hb_face_t    *face,
395 					unsigned int  lookup_index,
396 					hb_set_t     *glyphs
397 					/*TODO , hb_bool_t  inclusive */);
398 
399 HB_EXTERN void
400 hb_ot_layout_lookups_substitute_closure (hb_face_t      *face,
401 					 const hb_set_t *lookups,
402 					 hb_set_t       *glyphs);
403 
404 
405 /*
406  * GPOS
407  */
408 
409 HB_EXTERN hb_bool_t
410 hb_ot_layout_has_positioning (hb_face_t *face);
411 
412 /* Optical 'size' feature info.  Returns true if found.
413  * https://docs.microsoft.com/en-us/typography/opentype/spec/features_pt#size */
414 HB_EXTERN hb_bool_t
415 hb_ot_layout_get_size_params (hb_face_t       *face,
416 			      unsigned int    *design_size,       /* OUT.  May be NULL */
417 			      unsigned int    *subfamily_id,      /* OUT.  May be NULL */
418 			      hb_ot_name_id_t *subfamily_name_id, /* OUT.  May be NULL */
419 			      unsigned int    *range_start,       /* OUT.  May be NULL */
420 			      unsigned int    *range_end          /* OUT.  May be NULL */);
421 
422 HB_EXTERN hb_position_t
423 hb_ot_layout_lookup_get_optical_bound (hb_font_t      *font,
424 				       unsigned        lookup_index,
425 				       hb_direction_t  direction,
426 				       hb_codepoint_t  glyph);
427 
428 
429 /*
430  * GSUB/GPOS
431  */
432 
433 HB_EXTERN hb_bool_t
434 hb_ot_layout_feature_get_name_ids (hb_face_t       *face,
435 				   hb_tag_t         table_tag,
436 				   unsigned int     feature_index,
437 				   hb_ot_name_id_t *label_id             /* OUT.  May be NULL */,
438 				   hb_ot_name_id_t *tooltip_id           /* OUT.  May be NULL */,
439 				   hb_ot_name_id_t *sample_id            /* OUT.  May be NULL */,
440 				   unsigned int    *num_named_parameters /* OUT.  May be NULL */,
441 				   hb_ot_name_id_t *first_param_id       /* OUT.  May be NULL */);
442 
443 
444 HB_EXTERN unsigned int
445 hb_ot_layout_feature_get_characters (hb_face_t      *face,
446 				     hb_tag_t        table_tag,
447 				     unsigned int    feature_index,
448 				     unsigned int    start_offset,
449 				     unsigned int   *char_count    /* IN/OUT.  May be NULL */,
450 				     hb_codepoint_t *characters    /* OUT.     May be NULL */);
451 
452 
453 /*
454  * BASE
455  */
456 
457 HB_EXTERN hb_bool_t
458 hb_ot_layout_get_font_extents (hb_font_t         *font,
459 			       hb_direction_t     direction,
460 			       hb_tag_t           script_tag,
461 			       hb_tag_t           language_tag,
462 			       hb_font_extents_t *extents);
463 
464 HB_EXTERN hb_bool_t
465 hb_ot_layout_get_font_extents2 (hb_font_t         *font,
466 				hb_direction_t     direction,
467 				hb_script_t        script,
468 				hb_language_t      language,
469 				hb_font_extents_t *extents);
470 
471 /**
472  * hb_ot_layout_baseline_tag_t:
473  * @HB_OT_LAYOUT_BASELINE_TAG_ROMAN: The baseline used by alphabetic scripts such as Latin, Cyrillic and Greek.
474  * In vertical writing mode, the alphabetic baseline for characters rotated 90 degrees clockwise.
475  * (This would not apply to alphabetic characters that remain upright in vertical writing mode, since these
476  * characters are not rotated.)
477  * @HB_OT_LAYOUT_BASELINE_TAG_HANGING: The hanging baseline. In horizontal direction, this is the horizontal
478  * line from which syllables seem, to hang in Tibetan and other similar scripts. In vertical writing mode,
479  * for Tibetan (or some other similar script) characters rotated 90 degrees clockwise.
480  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT: Ideographic character face bottom or left edge,
481  * if the direction is horizontal or vertical, respectively.
482  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT: Ideographic character face top or right edge,
483  * if the direction is horizontal or vertical, respectively.
484  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_CENTRAL: The center of the ideographic character face. Since: 4.0.0
485  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT: Ideographic em-box bottom or left edge,
486  * if the direction is horizontal or vertical, respectively.
487  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT: Ideographic em-box top or right edge baseline,
488  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_CENTRAL: The center of the ideographic em-box. Since: 4.0.0
489  * if the direction is horizontal or vertical, respectively.
490  * @HB_OT_LAYOUT_BASELINE_TAG_MATH: The baseline about which mathematical characters are centered.
491  * In vertical writing mode when mathematical characters rotated 90 degrees clockwise, are centered.
492  *
493  * Baseline tags from [Baseline Tags](https://docs.microsoft.com/en-us/typography/opentype/spec/baselinetags) registry.
494  *
495  * Since: 2.6.0
496  */
497 typedef enum {
498   HB_OT_LAYOUT_BASELINE_TAG_ROMAN			= HB_TAG ('r','o','m','n'),
499   HB_OT_LAYOUT_BASELINE_TAG_HANGING			= HB_TAG ('h','a','n','g'),
500   HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT	= HB_TAG ('i','c','f','b'),
501   HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT	= HB_TAG ('i','c','f','t'),
502   HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_CENTRAL		= HB_TAG ('I','c','f','c'),
503   HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT	= HB_TAG ('i','d','e','o'),
504   HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT	= HB_TAG ('i','d','t','p'),
505   HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_CENTRAL		= HB_TAG ('I','d','c','e'),
506   HB_OT_LAYOUT_BASELINE_TAG_MATH			= HB_TAG ('m','a','t','h'),
507 
508   /*< private >*/
509   _HB_OT_LAYOUT_BASELINE_TAG_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
510 } hb_ot_layout_baseline_tag_t;
511 
512 HB_EXTERN hb_ot_layout_baseline_tag_t
513 hb_ot_layout_get_horizontal_baseline_tag_for_script (hb_script_t script);
514 
515 HB_EXTERN hb_bool_t
516 hb_ot_layout_get_baseline (hb_font_t                   *font,
517 			   hb_ot_layout_baseline_tag_t  baseline_tag,
518 			   hb_direction_t               direction,
519 			   hb_tag_t                     script_tag,
520 			   hb_tag_t                     language_tag,
521 			   hb_position_t               *coord        /* OUT.  May be NULL. */);
522 
523 HB_EXTERN hb_bool_t
524 hb_ot_layout_get_baseline2 (hb_font_t                   *font,
525 			    hb_ot_layout_baseline_tag_t  baseline_tag,
526 			    hb_direction_t               direction,
527 			    hb_script_t                  script,
528 			    hb_language_t                language,
529 			    hb_position_t               *coord        /* OUT.  May be NULL. */);
530 
531 HB_EXTERN void
532 hb_ot_layout_get_baseline_with_fallback (hb_font_t                   *font,
533 					 hb_ot_layout_baseline_tag_t  baseline_tag,
534 					 hb_direction_t               direction,
535 					 hb_tag_t                     script_tag,
536 					 hb_tag_t                     language_tag,
537 					 hb_position_t               *coord        /* OUT */);
538 
539 HB_EXTERN void
540 hb_ot_layout_get_baseline_with_fallback2 (hb_font_t                   *font,
541 					  hb_ot_layout_baseline_tag_t  baseline_tag,
542 					  hb_direction_t               direction,
543 					  hb_script_t                  script,
544 					  hb_language_t                language,
545 					  hb_position_t               *coord        /* OUT */);
546 
547 HB_END_DECLS
548 
549 #endif /* HB_OT_LAYOUT_H */
550