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 © 2012,2013 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.hh"
32
33#ifndef HB_NO_OT_LAYOUT
34
35#ifdef HB_NO_OT_TAG
36#error "Cannot compile hb-ot-layout.cc with HB_NO_OT_TAG."
37#endif
38
39#include "hb-open-type.hh"
40#include "hb-ot-layout.hh"
41#include "hb-ot-face.hh"
42#include "hb-ot-map.hh"
43#include "hb-map.hh"
44
45#include "hb-ot-kern-table.hh"
46#include "hb-ot-layout-gdef-table.hh"
47#include "hb-ot-layout-gsub-table.hh"
48#include "hb-ot-layout-gpos-table.hh"
49#include "hb-ot-layout-base-table.hh"
50#include "hb-ot-layout-jstf-table.hh" // Just so we compile it; unused otherwise.
51#include "hb-ot-name-table.hh"
52#include "hb-ot-os2-table.hh"
53
54#include "hb-aat-layout-morx-table.hh"
55#include "hb-aat-layout-opbd-table.hh" // Just so we compile it; unused otherwise.
56
57using OT::Layout::GSUB;
58using OT::Layout::GPOS;
59
60/**
61 * SECTION:hb-ot-layout
62 * @title: hb-ot-layout
63 * @short_description: OpenType Layout
64 * @include: hb-ot.h
65 *
66 * Functions for querying OpenType Layout features in the font face.
67 * See the [OpenType specification](http://www.microsoft.com/typography/otspec/)
68 * for details.
69 **/
70
71
72/*
73 * kern
74 */
75
76#ifndef HB_NO_OT_KERN
77/**
78 * hb_ot_layout_has_kerning:
79 * @face: The #hb_face_t to work on
80 *
81 * Tests whether a face includes any kerning data in the 'kern' table.
82 * Does NOT test for kerning lookups in the GPOS table.
83 *
84 * Return value: `true` if data found, `false` otherwise
85 *
86 **/
87bool
88hb_ot_layout_has_kerning (hb_face_t *face)
89{
90 return face->table.kern->has_data ();
91}
92
93/**
94 * hb_ot_layout_has_machine_kerning:
95 * @face: The #hb_face_t to work on
96 *
97 * Tests whether a face includes any state-machine kerning in the 'kern' table.
98 * Does NOT examine the GPOS table.
99 *
100 * Return value: `true` if data found, `false` otherwise
101 *
102 **/
103bool
104hb_ot_layout_has_machine_kerning (hb_face_t *face)
105{
106 return face->table.kern->has_state_machine ();
107}
108
109/**
110 * hb_ot_layout_has_cross_kerning:
111 * @face: The #hb_face_t to work on
112 *
113 * Tests whether a face has any cross-stream kerning (i.e., kerns
114 * that make adjustments perpendicular to the direction of the text
115 * flow: Y adjustments in horizontal text or X adjustments in
116 * vertical text) in the 'kern' table.
117 *
118 * Does NOT examine the GPOS table.
119 *
120 * Return value: `true` is data found, `false` otherwise
121 *
122 **/
123bool
124hb_ot_layout_has_cross_kerning (hb_face_t *face)
125{
126 return face->table.kern->has_cross_stream ();
127}
128
129void
130hb_ot_layout_kern (const hb_ot_shape_plan_t *plan,
131 hb_font_t *font,
132 hb_buffer_t *buffer)
133{
134 hb_blob_t *blob = font->face->table.kern.get_blob ();
135 const AAT::kern& kern = *blob->as<AAT::kern> ();
136
137 AAT::hb_aat_apply_context_t c (plan, font, buffer, blob);
138
139 if (!buffer->message (font, "start table kern")) return;
140 kern.apply (&c);
141 (void) buffer->message (font, "end table kern");
142}
143#endif
144
145
146/*
147 * GDEF
148 */
149
150bool
151OT::GDEF::is_blocklisted (hb_blob_t *blob,
152 hb_face_t *face) const
153{
154#ifdef HB_NO_OT_LAYOUT_BLOCKLIST
155 return false;
156#endif
157 /* The ugly business of blocklisting individual fonts' tables happen here!
158 * See this thread for why we finally had to bend in and do this:
159 * https://lists.freedesktop.org/archives/harfbuzz/2016-February/005489.html
160 *
161 * In certain versions of Times New Roman Italic and Bold Italic,
162 * ASCII double quotation mark U+0022 has wrong glyph class 3 (mark)
163 * in GDEF. Many versions of Tahoma have bad GDEF tables that
164 * incorrectly classify some spacing marks such as certain IPA
165 * symbols as glyph class 3. So do older versions of Microsoft
166 * Himalaya, and the version of Cantarell shipped by Ubuntu 16.04.
167 *
168 * Nuke the GDEF tables of to avoid unwanted width-zeroing.
169 *
170 * See https://bugzilla.mozilla.org/show_bug.cgi?id=1279925
171 * https://bugzilla.mozilla.org/show_bug.cgi?id=1279693
172 * https://bugzilla.mozilla.org/show_bug.cgi?id=1279875
173 */
174 switch HB_CODEPOINT_ENCODE3(blob->length,
175 face->table.GSUB->table.get_length (),
176 face->table.GPOS->table.get_length ())
177 {
178 /* sha1sum:c5ee92f0bca4bfb7d06c4d03e8cf9f9cf75d2e8a Windows 7? timesi.ttf */
179 case HB_CODEPOINT_ENCODE3 (442, 2874, 42038):
180 /* sha1sum:37fc8c16a0894ab7b749e35579856c73c840867b Windows 7? timesbi.ttf */
181 case HB_CODEPOINT_ENCODE3 (430, 2874, 40662):
182 /* sha1sum:19fc45110ea6cd3cdd0a5faca256a3797a069a80 Windows 7 timesi.ttf */
183 case HB_CODEPOINT_ENCODE3 (442, 2874, 39116):
184 /* sha1sum:6d2d3c9ed5b7de87bc84eae0df95ee5232ecde26 Windows 7 timesbi.ttf */
185 case HB_CODEPOINT_ENCODE3 (430, 2874, 39374):
186 /* sha1sum:8583225a8b49667c077b3525333f84af08c6bcd8 OS X 10.11.3 Times New Roman Italic.ttf */
187 case HB_CODEPOINT_ENCODE3 (490, 3046, 41638):
188 /* sha1sum:ec0f5a8751845355b7c3271d11f9918a966cb8c9 OS X 10.11.3 Times New Roman Bold Italic.ttf */
189 case HB_CODEPOINT_ENCODE3 (478, 3046, 41902):
190 /* sha1sum:96eda93f7d33e79962451c6c39a6b51ee893ce8c tahoma.ttf from Windows 8 */
191 case HB_CODEPOINT_ENCODE3 (898, 12554, 46470):
192 /* sha1sum:20928dc06014e0cd120b6fc942d0c3b1a46ac2bc tahomabd.ttf from Windows 8 */
193 case HB_CODEPOINT_ENCODE3 (910, 12566, 47732):
194 /* sha1sum:4f95b7e4878f60fa3a39ca269618dfde9721a79e tahoma.ttf from Windows 8.1 */
195 case HB_CODEPOINT_ENCODE3 (928, 23298, 59332):
196 /* sha1sum:6d400781948517c3c0441ba42acb309584b73033 tahomabd.ttf from Windows 8.1 */
197 case HB_CODEPOINT_ENCODE3 (940, 23310, 60732):
198 /* tahoma.ttf v6.04 from Windows 8.1 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
199 case HB_CODEPOINT_ENCODE3 (964, 23836, 60072):
200 /* tahomabd.ttf v6.04 from Windows 8.1 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
201 case HB_CODEPOINT_ENCODE3 (976, 23832, 61456):
202 /* sha1sum:e55fa2dfe957a9f7ec26be516a0e30b0c925f846 tahoma.ttf from Windows 10 */
203 case HB_CODEPOINT_ENCODE3 (994, 24474, 60336):
204 /* sha1sum:7199385abb4c2cc81c83a151a7599b6368e92343 tahomabd.ttf from Windows 10 */
205 case HB_CODEPOINT_ENCODE3 (1006, 24470, 61740):
206 /* tahoma.ttf v6.91 from Windows 10 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
207 case HB_CODEPOINT_ENCODE3 (1006, 24576, 61346):
208 /* tahomabd.ttf v6.91 from Windows 10 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
209 case HB_CODEPOINT_ENCODE3 (1018, 24572, 62828):
210 /* sha1sum:b9c84d820c49850d3d27ec498be93955b82772b5 tahoma.ttf from Windows 10 AU */
211 case HB_CODEPOINT_ENCODE3 (1006, 24576, 61352):
212 /* sha1sum:2bdfaab28174bdadd2f3d4200a30a7ae31db79d2 tahomabd.ttf from Windows 10 AU */
213 case HB_CODEPOINT_ENCODE3 (1018, 24572, 62834):
214 /* sha1sum:b0d36cf5a2fbe746a3dd277bffc6756a820807a7 Tahoma.ttf from Mac OS X 10.9 */
215 case HB_CODEPOINT_ENCODE3 (832, 7324, 47162):
216 /* sha1sum:12fc4538e84d461771b30c18b5eb6bd434e30fba Tahoma Bold.ttf from Mac OS X 10.9 */
217 case HB_CODEPOINT_ENCODE3 (844, 7302, 45474):
218 /* sha1sum:eb8afadd28e9cf963e886b23a30b44ab4fd83acc himalaya.ttf from Windows 7 */
219 case HB_CODEPOINT_ENCODE3 (180, 13054, 7254):
220 /* sha1sum:73da7f025b238a3f737aa1fde22577a6370f77b0 himalaya.ttf from Windows 8 */
221 case HB_CODEPOINT_ENCODE3 (192, 12638, 7254):
222 /* sha1sum:6e80fd1c0b059bbee49272401583160dc1e6a427 himalaya.ttf from Windows 8.1 */
223 case HB_CODEPOINT_ENCODE3 (192, 12690, 7254):
224 /* 8d9267aea9cd2c852ecfb9f12a6e834bfaeafe44 cantarell-fonts-0.0.21/otf/Cantarell-Regular.otf */
225 /* 983988ff7b47439ab79aeaf9a45bd4a2c5b9d371 cantarell-fonts-0.0.21/otf/Cantarell-Oblique.otf */
226 case HB_CODEPOINT_ENCODE3 (188, 248, 3852):
227 /* 2c0c90c6f6087ffbfea76589c93113a9cbb0e75f cantarell-fonts-0.0.21/otf/Cantarell-Bold.otf */
228 /* 55461f5b853c6da88069ffcdf7f4dd3f8d7e3e6b cantarell-fonts-0.0.21/otf/Cantarell-Bold-Oblique.otf */
229 case HB_CODEPOINT_ENCODE3 (188, 264, 3426):
230 /* d125afa82a77a6475ac0e74e7c207914af84b37a padauk-2.80/Padauk.ttf RHEL 7.2 */
231 case HB_CODEPOINT_ENCODE3 (1058, 47032, 11818):
232 /* 0f7b80437227b90a577cc078c0216160ae61b031 padauk-2.80/Padauk-Bold.ttf RHEL 7.2*/
233 case HB_CODEPOINT_ENCODE3 (1046, 47030, 12600):
234 /* d3dde9aa0a6b7f8f6a89ef1002e9aaa11b882290 padauk-2.80/Padauk.ttf Ubuntu 16.04 */
235 case HB_CODEPOINT_ENCODE3 (1058, 71796, 16770):
236 /* 5f3c98ccccae8a953be2d122c1b3a77fd805093f padauk-2.80/Padauk-Bold.ttf Ubuntu 16.04 */
237 case HB_CODEPOINT_ENCODE3 (1046, 71790, 17862):
238 /* 6c93b63b64e8b2c93f5e824e78caca555dc887c7 padauk-2.80/Padauk-book.ttf */
239 case HB_CODEPOINT_ENCODE3 (1046, 71788, 17112):
240 /* d89b1664058359b8ec82e35d3531931125991fb9 padauk-2.80/Padauk-bookbold.ttf */
241 case HB_CODEPOINT_ENCODE3 (1058, 71794, 17514):
242 /* 824cfd193aaf6234b2b4dc0cf3c6ef576c0d00ef padauk-3.0/Padauk-book.ttf */
243 case HB_CODEPOINT_ENCODE3 (1330, 109904, 57938):
244 /* 91fcc10cf15e012d27571e075b3b4dfe31754a8a padauk-3.0/Padauk-bookbold.ttf */
245 case HB_CODEPOINT_ENCODE3 (1330, 109904, 58972):
246 /* sha1sum: c26e41d567ed821bed997e937bc0c41435689e85 Padauk.ttf
247 * "Padauk Regular" "Version 2.5", see https://crbug.com/681813 */
248 case HB_CODEPOINT_ENCODE3 (1004, 59092, 14836):
249 return true;
250 }
251 return false;
252}
253
254static void
255_hb_ot_layout_set_glyph_props (hb_font_t *font,
256 hb_buffer_t *buffer)
257{
258 _hb_buffer_assert_gsubgpos_vars (buffer);
259
260 const auto &gdef = *font->face->table.GDEF;
261 unsigned int count = buffer->len;
262 hb_glyph_info_t *info = buffer->info;
263 for (unsigned int i = 0; i < count; i++)
264 {
265 _hb_glyph_info_set_glyph_props (&info[i], gdef.get_glyph_props (info[i].codepoint));
266 _hb_glyph_info_clear_lig_props (&info[i]);
267 }
268}
269
270/* Public API */
271
272/**
273 * hb_ot_layout_has_glyph_classes:
274 * @face: #hb_face_t to work upon
275 *
276 * Tests whether a face has any glyph classes defined in its GDEF table.
277 *
278 * Return value: `true` if data found, `false` otherwise
279 *
280 **/
281hb_bool_t
282hb_ot_layout_has_glyph_classes (hb_face_t *face)
283{
284 return face->table.GDEF->table->has_glyph_classes ();
285}
286
287/**
288 * hb_ot_layout_get_glyph_class:
289 * @face: The #hb_face_t to work on
290 * @glyph: The #hb_codepoint_t code point to query
291 *
292 * Fetches the GDEF class of the requested glyph in the specified face.
293 *
294 * Return value: The #hb_ot_layout_glyph_class_t glyph class of the given code
295 * point in the GDEF table of the face.
296 *
297 * Since: 0.9.7
298 **/
299hb_ot_layout_glyph_class_t
300hb_ot_layout_get_glyph_class (hb_face_t *face,
301 hb_codepoint_t glyph)
302{
303 return (hb_ot_layout_glyph_class_t) face->table.GDEF->table->get_glyph_class (glyph);
304}
305
306/**
307 * hb_ot_layout_get_glyphs_in_class:
308 * @face: The #hb_face_t to work on
309 * @klass: The #hb_ot_layout_glyph_class_t GDEF class to retrieve
310 * @glyphs: (out): The #hb_set_t set of all glyphs belonging to the requested
311 * class.
312 *
313 * Retrieves the set of all glyphs from the face that belong to the requested
314 * glyph class in the face's GDEF table.
315 *
316 * Since: 0.9.7
317 **/
318void
319hb_ot_layout_get_glyphs_in_class (hb_face_t *face,
320 hb_ot_layout_glyph_class_t klass,
321 hb_set_t *glyphs /* OUT */)
322{
323 return face->table.GDEF->table->get_glyphs_in_class (klass, glyphs);
324}
325
326#ifndef HB_NO_LAYOUT_UNUSED
327/**
328 * hb_ot_layout_get_attach_points:
329 * @face: The #hb_face_t to work on
330 * @glyph: The #hb_codepoint_t code point to query
331 * @start_offset: offset of the first attachment point to retrieve
332 * @point_count: (inout) (optional): Input = the maximum number of attachment points to return;
333 * Output = the actual number of attachment points returned (may be zero)
334 * @point_array: (out) (array length=point_count): The array of attachment points found for the query
335 *
336 * Fetches a list of all attachment points for the specified glyph in the GDEF
337 * table of the face. The list returned will begin at the offset provided.
338 *
339 * Useful if the client program wishes to cache the list.
340 *
341 * Return value: Total number of attachment points for @glyph.
342 *
343 **/
344unsigned int
345hb_ot_layout_get_attach_points (hb_face_t *face,
346 hb_codepoint_t glyph,
347 unsigned int start_offset,
348 unsigned int *point_count /* IN/OUT */,
349 unsigned int *point_array /* OUT */)
350{
351 return face->table.GDEF->table->get_attach_points (glyph,
352 start_offset,
353 point_count,
354 point_array);
355}
356/**
357 * hb_ot_layout_get_ligature_carets:
358 * @font: The #hb_font_t to work on
359 * @direction: The #hb_direction_t text direction to use
360 * @glyph: The #hb_codepoint_t code point to query
361 * @start_offset: offset of the first caret position to retrieve
362 * @caret_count: (inout) (optional): Input = the maximum number of caret positions to return;
363 * Output = the actual number of caret positions returned (may be zero)
364 * @caret_array: (out) (array length=caret_count): The array of caret positions found for the query
365 *
366 * Fetches a list of the caret positions defined for a ligature glyph in the GDEF
367 * table of the font. The list returned will begin at the offset provided.
368 *
369 * Note that a ligature that is formed from n characters will have n-1
370 * caret positions. The first character is not represented in the array,
371 * since its caret position is the glyph position.
372 *
373 * The positions returned by this function are 'unshaped', and will have to
374 * be fixed up for kerning that may be applied to the ligature glyph.
375 *
376 * Return value: Total number of ligature caret positions for @glyph.
377 *
378 **/
379unsigned int
380hb_ot_layout_get_ligature_carets (hb_font_t *font,
381 hb_direction_t direction,
382 hb_codepoint_t glyph,
383 unsigned int start_offset,
384 unsigned int *caret_count /* IN/OUT */,
385 hb_position_t *caret_array /* OUT */)
386{
387 return font->face->table.GDEF->table->get_lig_carets (font, direction, glyph, start_offset, caret_count, caret_array);
388}
389#endif
390
391
392/*
393 * GSUB/GPOS
394 */
395
396bool
397GSUB::is_blocklisted (hb_blob_t *blob HB_UNUSED,
398 hb_face_t *face) const
399{
400#ifdef HB_NO_OT_LAYOUT_BLOCKLIST
401 return false;
402#endif
403 return false;
404}
405
406bool
407GPOS::is_blocklisted (hb_blob_t *blob HB_UNUSED,
408 hb_face_t *face HB_UNUSED) const
409{
410#ifdef HB_NO_OT_LAYOUT_BLOCKLIST
411 return false;
412#endif
413 return false;
414}
415
416static const OT::GSUBGPOS&
417get_gsubgpos_table (hb_face_t *face,
418 hb_tag_t table_tag)
419{
420 switch (table_tag) {
421 case HB_OT_TAG_GSUB: return *face->table.GSUB->table;
422 case HB_OT_TAG_GPOS: return *face->table.GPOS->table;
423 default: return Null (OT::GSUBGPOS);
424 }
425}
426
427
428/**
429 * hb_ot_layout_table_get_script_tags:
430 * @face: #hb_face_t to work upon
431 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
432 * @start_offset: offset of the first script tag to retrieve
433 * @script_count: (inout) (optional): Input = the maximum number of script tags to return;
434 * Output = the actual number of script tags returned (may be zero)
435 * @script_tags: (out) (array length=script_count): The array of #hb_tag_t script tags found for the query
436 *
437 * Fetches a list of all scripts enumerated in the specified face's GSUB table
438 * or GPOS table. The list returned will begin at the offset provided.
439 *
440 * Return value: Total number of script tags.
441 *
442 **/
443unsigned int
444hb_ot_layout_table_get_script_tags (hb_face_t *face,
445 hb_tag_t table_tag,
446 unsigned int start_offset,
447 unsigned int *script_count /* IN/OUT */,
448 hb_tag_t *script_tags /* OUT */)
449{
450 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
451
452 return g.get_script_tags (start_offset, script_count, script_tags);
453}
454
455#define HB_OT_TAG_LATIN_SCRIPT HB_TAG ('l', 'a', 't', 'n')
456
457/**
458 * hb_ot_layout_table_find_script:
459 * @face: #hb_face_t to work upon
460 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
461 * @script_tag: #hb_tag_t of the script tag requested
462 * @script_index: (out): The index of the requested script tag
463 *
464 * Fetches the index if a given script tag in the specified face's GSUB table
465 * or GPOS table.
466 *
467 * Return value: `true` if the script is found, `false` otherwise
468 *
469 **/
470hb_bool_t
471hb_ot_layout_table_find_script (hb_face_t *face,
472 hb_tag_t table_tag,
473 hb_tag_t script_tag,
474 unsigned int *script_index /* OUT */)
475{
476 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX), "");
477 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
478
479 if (g.find_script_index (script_tag, script_index))
480 return true;
481
482 /* try finding 'DFLT' */
483 if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index))
484 return false;
485
486 /* try with 'dflt'; MS site has had typos and many fonts use it now :(.
487 * including many versions of DejaVu Sans Mono! */
488 if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index))
489 return false;
490
491 /* try with 'latn'; some old fonts put their features there even though
492 they're really trying to support Thai, for example :( */
493 if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index))
494 return false;
495
496 if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
497 return false;
498}
499
500#ifndef HB_DISABLE_DEPRECATED
501/**
502 * hb_ot_layout_table_choose_script:
503 * @face: #hb_face_t to work upon
504 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
505 * @script_tags: Array of #hb_tag_t script tags
506 * @script_index: (out): The index of the chosen script
507 * @chosen_script: (out): #hb_tag_t of the chosen script
508 *
509 * Deprecated since 2.0.0
510 **/
511hb_bool_t
512hb_ot_layout_table_choose_script (hb_face_t *face,
513 hb_tag_t table_tag,
514 const hb_tag_t *script_tags,
515 unsigned int *script_index /* OUT */,
516 hb_tag_t *chosen_script /* OUT */)
517{
518 const hb_tag_t *t;
519 for (t = script_tags; *t; t++);
520 return hb_ot_layout_table_select_script (face, table_tag, t - script_tags, script_tags, script_index, chosen_script);
521}
522#endif
523
524/**
525 * hb_ot_layout_table_select_script:
526 * @face: #hb_face_t to work upon
527 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
528 * @script_count: Number of script tags in the array
529 * @script_tags: Array of #hb_tag_t script tags
530 * @script_index: (out) (optional): The index of the requested script
531 * @chosen_script: (out) (optional): #hb_tag_t of the requested script
532 *
533 * Selects an OpenType script for @table_tag from the @script_tags array.
534 *
535 * If the table does not have any of the requested scripts, then `DFLT`,
536 * `dflt`, and `latn` tags are tried in that order. If the table still does not
537 * have any of these scripts, @script_index is set to
538 * #HB_OT_LAYOUT_NO_SCRIPT_INDEX and @chosen_script is set to #HB_TAG_NONE.
539 *
540 * Return value:
541 * `true` if one of the requested scripts is selected, `false` if a fallback
542 * script is selected or if no scripts are selected.
543 *
544 * Since: 2.0.0
545 **/
546hb_bool_t
547hb_ot_layout_table_select_script (hb_face_t *face,
548 hb_tag_t table_tag,
549 unsigned int script_count,
550 const hb_tag_t *script_tags,
551 unsigned int *script_index /* OUT */,
552 hb_tag_t *chosen_script /* OUT */)
553{
554 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX), "");
555 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
556 unsigned int i;
557
558 for (i = 0; i < script_count; i++)
559 {
560 if (g.find_script_index (script_tags[i], script_index))
561 {
562 if (chosen_script)
563 *chosen_script = script_tags[i];
564 return true;
565 }
566 }
567
568 /* try finding 'DFLT' */
569 if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index)) {
570 if (chosen_script)
571 *chosen_script = HB_OT_TAG_DEFAULT_SCRIPT;
572 return false;
573 }
574
575 /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
576 if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index)) {
577 if (chosen_script)
578 *chosen_script = HB_OT_TAG_DEFAULT_LANGUAGE;
579 return false;
580 }
581
582 /* try with 'latn'; some old fonts put their features there even though
583 they're really trying to support Thai, for example :( */
584 if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index)) {
585 if (chosen_script)
586 *chosen_script = HB_OT_TAG_LATIN_SCRIPT;
587 return false;
588 }
589
590 if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
591 if (chosen_script)
592 *chosen_script = HB_TAG_NONE;
593 return false;
594}
595
596
597/**
598 * hb_ot_layout_table_get_feature_tags:
599 * @face: #hb_face_t to work upon
600 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
601 * @start_offset: offset of the first feature tag to retrieve
602 * @feature_count: (inout) (optional): Input = the maximum number of feature tags to return;
603 * Output = the actual number of feature tags returned (may be zero)
604 * @feature_tags: (out) (array length=feature_count): Array of feature tags found in the table
605 *
606 * Fetches a list of all feature tags in the given face's GSUB or GPOS table.
607 * Note that there might be duplicate feature tags, belonging to different
608 * script/language-system pairs of the table.
609 *
610 * Return value: Total number of feature tags.
611 *
612 * Since: 0.6.0
613 *
614 **/
615unsigned int
616hb_ot_layout_table_get_feature_tags (hb_face_t *face,
617 hb_tag_t table_tag,
618 unsigned int start_offset,
619 unsigned int *feature_count /* IN/OUT */,
620 hb_tag_t *feature_tags /* OUT */)
621{
622 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
623
624 return g.get_feature_tags (start_offset, feature_count, feature_tags);
625}
626
627
628/**
629 * hb_ot_layout_table_find_feature:
630 * @face: #hb_face_t to work upon
631 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
632 * @feature_tag: The #hb_tag_t of the requested feature tag
633 * @feature_index: (out): The index of the requested feature
634 *
635 * Fetches the index for a given feature tag in the specified face's GSUB table
636 * or GPOS table.
637 *
638 * Return value: `true` if the feature is found, `false` otherwise
639 *
640 * Since: 0.6.0
641 *
642 **/
643bool
644hb_ot_layout_table_find_feature (hb_face_t *face,
645 hb_tag_t table_tag,
646 hb_tag_t feature_tag,
647 unsigned int *feature_index /* OUT */)
648{
649 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX), "");
650 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
651
652 unsigned int num_features = g.get_feature_count ();
653 for (unsigned int i = 0; i < num_features; i++)
654 {
655 if (feature_tag == g.get_feature_tag (i)) {
656 if (feature_index) *feature_index = i;
657 return true;
658 }
659 }
660
661 if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
662 return false;
663}
664
665
666/**
667 * hb_ot_layout_script_get_language_tags:
668 * @face: #hb_face_t to work upon
669 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
670 * @script_index: The index of the requested script tag
671 * @start_offset: offset of the first language tag to retrieve
672 * @language_count: (inout) (optional): Input = the maximum number of language tags to return;
673 * Output = the actual number of language tags returned (may be zero)
674 * @language_tags: (out) (array length=language_count): Array of language tags found in the table
675 *
676 * Fetches a list of language tags in the given face's GSUB or GPOS table, underneath
677 * the specified script index. The list returned will begin at the offset provided.
678 *
679 * Return value: Total number of language tags.
680 *
681 * Since: 0.6.0
682 *
683 **/
684unsigned int
685hb_ot_layout_script_get_language_tags (hb_face_t *face,
686 hb_tag_t table_tag,
687 unsigned int script_index,
688 unsigned int start_offset,
689 unsigned int *language_count /* IN/OUT */,
690 hb_tag_t *language_tags /* OUT */)
691{
692 const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
693
694 return s.get_lang_sys_tags (start_offset, language_count, language_tags);
695}
696
697
698#ifndef HB_DISABLE_DEPRECATED
699/**
700 * hb_ot_layout_script_find_language:
701 * @face: #hb_face_t to work upon
702 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
703 * @script_index: The index of the requested script tag
704 * @language_tag: The #hb_tag_t of the requested language
705 * @language_index: The index of the requested language
706 *
707 * Fetches the index of a given language tag in the specified face's GSUB table
708 * or GPOS table, underneath the specified script tag.
709 *
710 * Return value: `true` if the language tag is found, `false` otherwise
711 *
712 * Since: 0.6.0
713 * Deprecated: 2.0.0
714 **/
715hb_bool_t
716hb_ot_layout_script_find_language (hb_face_t *face,
717 hb_tag_t table_tag,
718 unsigned int script_index,
719 hb_tag_t language_tag,
720 unsigned int *language_index)
721{
722 return hb_ot_layout_script_select_language (face,
723 table_tag,
724 script_index,
725 1,
726 &language_tag,
727 language_index);
728}
729#endif
730
731
732/**
733 * hb_ot_layout_script_select_language2:
734 * @face: #hb_face_t to work upon
735 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
736 * @script_index: The index of the requested script tag
737 * @language_count: The number of languages in the specified script
738 * @language_tags: The array of language tags
739 * @language_index: (out): The index of the chosen language
740 * @chosen_language: (out): #hb_tag_t of the chosen language
741 *
742 * Fetches the index of the first language tag fom @language_tags that is present
743 * in the specified face's GSUB or GPOS table, underneath the specified script
744 * index.
745 *
746 * If none of the given language tags is found, `false` is returned and
747 * @language_index is set to #HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX and
748 * @chosen_language is set to #HB_TAG_NONE.
749 *
750 * Return value: `true` if one of the given language tags is found, `false` otherwise
751 *
752 * Since: 7.0.0
753 **/
754hb_bool_t
755hb_ot_layout_script_select_language2 (hb_face_t *face,
756 hb_tag_t table_tag,
757 unsigned int script_index,
758 unsigned int language_count,
759 const hb_tag_t *language_tags,
760 unsigned int *language_index /* OUT */,
761 hb_tag_t *chosen_language /* OUT */)
762{
763 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX), "");
764 const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
765 unsigned int i;
766
767 for (i = 0; i < language_count; i++)
768 {
769 if (s.find_lang_sys_index (language_tags[i], language_index))
770 {
771 if (chosen_language)
772 *chosen_language = language_tags[i];
773 return true;
774 }
775 }
776
777 /* try finding 'dflt' */
778 if (s.find_lang_sys_index (HB_OT_TAG_DEFAULT_LANGUAGE, language_index))
779 {
780 if (chosen_language)
781 *chosen_language = HB_OT_TAG_DEFAULT_LANGUAGE;
782 return false;
783 }
784
785 if (language_index)
786 *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
787 if (chosen_language)
788 *chosen_language = HB_TAG_NONE;
789 return false;
790}
791
792/**
793 * hb_ot_layout_script_select_language:
794 * @face: #hb_face_t to work upon
795 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
796 * @script_index: The index of the requested script tag
797 * @language_count: The number of languages in the specified script
798 * @language_tags: The array of language tags
799 * @language_index: (out): The index of the requested language
800 *
801 * Fetches the index of the first language tag fom @language_tags that is present
802 * in the specified face's GSUB or GPOS table, underneath the specified script
803 * index.
804 *
805 * If none of the given language tags is found, `false` is returned and
806 * @language_index is set to the default language index.
807 *
808 * Return value: `true` if one of the given language tags is found, `false` otherwise
809 *
810 * Since: 2.0.0
811 **/
812hb_bool_t
813hb_ot_layout_script_select_language (hb_face_t *face,
814 hb_tag_t table_tag,
815 unsigned int script_index,
816 unsigned int language_count,
817 const hb_tag_t *language_tags,
818 unsigned int *language_index /* OUT */)
819{
820 return hb_ot_layout_script_select_language2 (face, table_tag,
821 script_index,
822 language_count, language_tags,
823 language_index, nullptr);
824}
825
826/**
827 * hb_ot_layout_language_get_required_feature_index:
828 * @face: #hb_face_t to work upon
829 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
830 * @script_index: The index of the requested script tag
831 * @language_index: The index of the requested language tag
832 * @feature_index: (out): The index of the requested feature
833 *
834 * Fetches the index of a requested feature in the given face's GSUB or GPOS table,
835 * underneath the specified script and language.
836 *
837 * Return value: `true` if the feature is found, `false` otherwise
838 *
839 * Since: 0.6.0
840 *
841 **/
842hb_bool_t
843hb_ot_layout_language_get_required_feature_index (hb_face_t *face,
844 hb_tag_t table_tag,
845 unsigned int script_index,
846 unsigned int language_index,
847 unsigned int *feature_index /* OUT */)
848{
849 return hb_ot_layout_language_get_required_feature (face,
850 table_tag,
851 script_index,
852 language_index,
853 feature_index,
854 nullptr);
855}
856
857
858/**
859 * hb_ot_layout_language_get_required_feature:
860 * @face: #hb_face_t to work upon
861 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
862 * @script_index: The index of the requested script tag
863 * @language_index: The index of the requested language tag
864 * @feature_index: (out): The index of the requested feature
865 * @feature_tag: (out): The #hb_tag_t of the requested feature
866 *
867 * Fetches the tag of a requested feature index in the given face's GSUB or GPOS table,
868 * underneath the specified script and language.
869 *
870 * Return value: `true` if the feature is found, `false` otherwise
871 *
872 * Since: 0.9.30
873 **/
874hb_bool_t
875hb_ot_layout_language_get_required_feature (hb_face_t *face,
876 hb_tag_t table_tag,
877 unsigned int script_index,
878 unsigned int language_index,
879 unsigned int *feature_index /* OUT */,
880 hb_tag_t *feature_tag /* OUT */)
881{
882 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
883 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
884
885 unsigned int index = l.get_required_feature_index ();
886 if (feature_index) *feature_index = index;
887 if (feature_tag) *feature_tag = g.get_feature_tag (index);
888
889 return l.has_required_feature ();
890}
891
892
893/**
894 * hb_ot_layout_language_get_feature_indexes:
895 * @face: #hb_face_t to work upon
896 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
897 * @script_index: The index of the requested script tag
898 * @language_index: The index of the requested language tag
899 * @start_offset: offset of the first feature tag to retrieve
900 * @feature_count: (inout) (optional): Input = the maximum number of feature tags to return;
901 * Output: the actual number of feature tags returned (may be zero)
902 * @feature_indexes: (out) (array length=feature_count): The array of feature indexes found for the query
903 *
904 * Fetches a list of all features in the specified face's GSUB table
905 * or GPOS table, underneath the specified script and language. The list
906 * returned will begin at the offset provided.
907 *
908 * Return value: Total number of features.
909 *
910 * Since: 0.6.0
911 *
912 **/
913unsigned int
914hb_ot_layout_language_get_feature_indexes (hb_face_t *face,
915 hb_tag_t table_tag,
916 unsigned int script_index,
917 unsigned int language_index,
918 unsigned int start_offset,
919 unsigned int *feature_count /* IN/OUT */,
920 unsigned int *feature_indexes /* OUT */)
921{
922 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
923 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
924
925 return l.get_feature_indexes (start_offset, feature_count, feature_indexes);
926}
927
928
929/**
930 * hb_ot_layout_language_get_feature_tags:
931 * @face: #hb_face_t to work upon
932 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
933 * @script_index: The index of the requested script tag
934 * @language_index: The index of the requested language tag
935 * @start_offset: offset of the first feature tag to retrieve
936 * @feature_count: (inout) (optional): Input = the maximum number of feature tags to return;
937 * Output = the actual number of feature tags returned (may be zero)
938 * @feature_tags: (out) (array length=feature_count): The array of #hb_tag_t feature tags found for the query
939 *
940 * Fetches a list of all features in the specified face's GSUB table
941 * or GPOS table, underneath the specified script and language. The list
942 * returned will begin at the offset provided.
943 *
944 * Return value: Total number of feature tags.
945 *
946 * Since: 0.6.0
947 *
948 **/
949unsigned int
950hb_ot_layout_language_get_feature_tags (hb_face_t *face,
951 hb_tag_t table_tag,
952 unsigned int script_index,
953 unsigned int language_index,
954 unsigned int start_offset,
955 unsigned int *feature_count /* IN/OUT */,
956 hb_tag_t *feature_tags /* OUT */)
957{
958 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
959 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
960
961 static_assert ((sizeof (unsigned int) == sizeof (hb_tag_t)), "");
962 unsigned int ret = l.get_feature_indexes (start_offset, feature_count, (unsigned int *) feature_tags);
963
964 if (feature_tags) {
965 unsigned int count = *feature_count;
966 for (unsigned int i = 0; i < count; i++)
967 feature_tags[i] = g.get_feature_tag ((unsigned int) feature_tags[i]);
968 }
969
970 return ret;
971}
972
973
974/**
975 * hb_ot_layout_language_find_feature:
976 * @face: #hb_face_t to work upon
977 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
978 * @script_index: The index of the requested script tag
979 * @language_index: The index of the requested language tag
980 * @feature_tag: #hb_tag_t of the feature tag requested
981 * @feature_index: (out): The index of the requested feature
982 *
983 * Fetches the index of a given feature tag in the specified face's GSUB table
984 * or GPOS table, underneath the specified script and language.
985 *
986 * Return value: `true` if the feature is found, `false` otherwise
987 *
988 * Since: 0.6.0
989 *
990 **/
991hb_bool_t
992hb_ot_layout_language_find_feature (hb_face_t *face,
993 hb_tag_t table_tag,
994 unsigned int script_index,
995 unsigned int language_index,
996 hb_tag_t feature_tag,
997 unsigned int *feature_index /* OUT */)
998{
999 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX), "");
1000 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1001 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
1002
1003 unsigned int num_features = l.get_feature_count ();
1004 for (unsigned int i = 0; i < num_features; i++) {
1005 unsigned int f_index = l.get_feature_index (i);
1006
1007 if (feature_tag == g.get_feature_tag (f_index)) {
1008 if (feature_index) *feature_index = f_index;
1009 return true;
1010 }
1011 }
1012
1013 if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
1014 return false;
1015}
1016
1017
1018/**
1019 * hb_ot_layout_feature_get_lookups:
1020 * @face: #hb_face_t to work upon
1021 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1022 * @feature_index: The index of the requested feature
1023 * @start_offset: offset of the first lookup to retrieve
1024 * @lookup_count: (inout) (optional): Input = the maximum number of lookups to return;
1025 * Output = the actual number of lookups returned (may be zero)
1026 * @lookup_indexes: (out) (array length=lookup_count): The array of lookup indexes found for the query
1027 *
1028 * Fetches a list of all lookups enumerated for the specified feature, in
1029 * the specified face's GSUB table or GPOS table. The list returned will
1030 * begin at the offset provided.
1031 *
1032 * Return value: Total number of lookups.
1033 *
1034 * Since: 0.9.7
1035 **/
1036unsigned int
1037hb_ot_layout_feature_get_lookups (hb_face_t *face,
1038 hb_tag_t table_tag,
1039 unsigned int feature_index,
1040 unsigned int start_offset,
1041 unsigned int *lookup_count /* IN/OUT */,
1042 unsigned int *lookup_indexes /* OUT */)
1043{
1044 return hb_ot_layout_feature_with_variations_get_lookups (face,
1045 table_tag,
1046 feature_index,
1047 HB_OT_LAYOUT_NO_VARIATIONS_INDEX,
1048 start_offset,
1049 lookup_count,
1050 lookup_indexes);
1051}
1052
1053
1054/**
1055 * hb_ot_layout_table_get_lookup_count:
1056 * @face: #hb_face_t to work upon
1057 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1058 *
1059 * Fetches the total number of lookups enumerated in the specified
1060 * face's GSUB table or GPOS table.
1061 *
1062 * Return value: Total number of lookups.
1063 *
1064 * Since: 0.9.22
1065 **/
1066unsigned int
1067hb_ot_layout_table_get_lookup_count (hb_face_t *face,
1068 hb_tag_t table_tag)
1069{
1070 return get_gsubgpos_table (face, table_tag).get_lookup_count ();
1071}
1072
1073
1074struct hb_collect_features_context_t
1075{
1076 hb_collect_features_context_t (hb_face_t *face,
1077 hb_tag_t table_tag,
1078 hb_set_t *feature_indices_,
1079 const hb_tag_t *features)
1080
1081 : g (get_gsubgpos_table (face, table_tag)),
1082 feature_indices (feature_indices_),
1083 has_feature_filter (false),
1084 script_count (0),langsys_count (0), feature_index_count (0)
1085 {
1086 compute_feature_filter (features);
1087 }
1088
1089 void compute_feature_filter (const hb_tag_t *features)
1090 {
1091 if (features == nullptr)
1092 {
1093 has_feature_filter = false;
1094 return;
1095 }
1096
1097 has_feature_filter = true;
1098 hb_set_t features_set;
1099 for (; *features; features++)
1100 features_set.add (*features);
1101
1102 for (unsigned i = 0; i < g.get_feature_count (); i++)
1103 {
1104 hb_tag_t tag = g.get_feature_tag (i);
1105 if (features_set.has (tag))
1106 feature_indices_filter.add(i);
1107 }
1108 }
1109
1110 bool visited (const OT::Script &s)
1111 {
1112 /* We might have Null() object here. Don't want to involve
1113 * that in the memoize. So, detect empty objects and return. */
1114 if (unlikely (!s.has_default_lang_sys () &&
1115 !s.get_lang_sys_count ()))
1116 return true;
1117
1118 if (script_count++ > HB_MAX_SCRIPTS)
1119 return true;
1120
1121 return visited (s, visited_script);
1122 }
1123 bool visited (const OT::LangSys &l)
1124 {
1125 /* We might have Null() object here. Don't want to involve
1126 * that in the memoize. So, detect empty objects and return. */
1127 if (unlikely (!l.has_required_feature () &&
1128 !l.get_feature_count ()))
1129 return true;
1130
1131 if (langsys_count++ > HB_MAX_LANGSYS)
1132 return true;
1133
1134 return visited (l, visited_langsys);
1135 }
1136
1137 bool visited_feature_indices (unsigned count)
1138 {
1139 feature_index_count += count;
1140 return feature_index_count > HB_MAX_FEATURE_INDICES;
1141 }
1142
1143 private:
1144 template <typename T>
1145 bool visited (const T &p, hb_set_t &visited_set)
1146 {
1147 hb_codepoint_t delta = (hb_codepoint_t) ((uintptr_t) &p - (uintptr_t) &g);
1148 if (visited_set.has (delta))
1149 return true;
1150
1151 visited_set.add (delta);
1152 return false;
1153 }
1154
1155 public:
1156 const OT::GSUBGPOS &g;
1157 hb_set_t *feature_indices;
1158 hb_set_t feature_indices_filter;
1159 bool has_feature_filter;
1160
1161 private:
1162 hb_set_t visited_script;
1163 hb_set_t visited_langsys;
1164 unsigned int script_count;
1165 unsigned int langsys_count;
1166 unsigned int feature_index_count;
1167};
1168
1169static void
1170langsys_collect_features (hb_collect_features_context_t *c,
1171 const OT::LangSys &l)
1172{
1173 if (c->visited (l)) return;
1174
1175 if (!c->has_feature_filter)
1176 {
1177 /* All features. */
1178 if (l.has_required_feature () && !c->visited_feature_indices (1))
1179 c->feature_indices->add (l.get_required_feature_index ());
1180
1181 // TODO(garretrieger): filter out indices >= feature count?
1182 if (!c->visited_feature_indices (l.featureIndex.len))
1183 l.add_feature_indexes_to (c->feature_indices);
1184 }
1185 else
1186 {
1187 if (c->feature_indices_filter.is_empty()) return;
1188 unsigned int num_features = l.get_feature_count ();
1189 for (unsigned int i = 0; i < num_features; i++)
1190 {
1191 unsigned int feature_index = l.get_feature_index (i);
1192 if (!c->feature_indices_filter.has (feature_index)) continue;
1193
1194 c->feature_indices->add (feature_index);
1195 c->feature_indices_filter.del (feature_index);
1196 }
1197 }
1198}
1199
1200static void
1201script_collect_features (hb_collect_features_context_t *c,
1202 const OT::Script &s,
1203 const hb_tag_t *languages)
1204{
1205 if (c->visited (s)) return;
1206
1207 if (!languages)
1208 {
1209 /* All languages. */
1210 if (s.has_default_lang_sys ())
1211 langsys_collect_features (c,
1212 s.get_default_lang_sys ());
1213
1214
1215 unsigned int count = s.get_lang_sys_count ();
1216 for (unsigned int language_index = 0; language_index < count; language_index++)
1217 langsys_collect_features (c,
1218 s.get_lang_sys (language_index));
1219 }
1220 else
1221 {
1222 for (; *languages; languages++)
1223 {
1224 unsigned int language_index;
1225 if (s.find_lang_sys_index (*languages, &language_index))
1226 langsys_collect_features (c,
1227 s.get_lang_sys (language_index));
1228
1229 }
1230 }
1231}
1232
1233
1234/**
1235 * hb_ot_layout_collect_features:
1236 * @face: #hb_face_t to work upon
1237 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1238 * @scripts: (nullable) (array zero-terminated=1): The array of scripts to collect features for,
1239 * terminated by %HB_TAG_NONE
1240 * @languages: (nullable) (array zero-terminated=1): The array of languages to collect features for,
1241 * terminated by %HB_TAG_NONE
1242 * @features: (nullable) (array zero-terminated=1): The array of features to collect,
1243 * terminated by %HB_TAG_NONE
1244 * @feature_indexes: (out): The set of feature indexes found for the query
1245 *
1246 * Fetches a list of all feature indexes in the specified face's GSUB table
1247 * or GPOS table, underneath the specified scripts, languages, and features.
1248 * If no list of scripts is provided, all scripts will be queried. If no list
1249 * of languages is provided, all languages will be queried. If no list of
1250 * features is provided, all features will be queried.
1251 *
1252 * Since: 1.8.5
1253 **/
1254void
1255hb_ot_layout_collect_features (hb_face_t *face,
1256 hb_tag_t table_tag,
1257 const hb_tag_t *scripts,
1258 const hb_tag_t *languages,
1259 const hb_tag_t *features,
1260 hb_set_t *feature_indexes /* OUT */)
1261{
1262 hb_collect_features_context_t c (face, table_tag, feature_indexes, features);
1263 if (!scripts)
1264 {
1265 /* All scripts. */
1266 unsigned int count = c.g.get_script_count ();
1267 for (unsigned int script_index = 0; script_index < count; script_index++)
1268 script_collect_features (&c,
1269 c.g.get_script (script_index),
1270 languages);
1271 }
1272 else
1273 {
1274 for (; *scripts; scripts++)
1275 {
1276 unsigned int script_index;
1277 if (c.g.find_script_index (*scripts, &script_index))
1278 script_collect_features (&c,
1279 c.g.get_script (script_index),
1280 languages);
1281 }
1282 }
1283}
1284
1285/**
1286 * hb_ot_layout_collect_features_map:
1287 * @face: #hb_face_t to work upon
1288 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1289 * @script_index: The index of the requested script tag
1290 * @language_index: The index of the requested language tag
1291 * @feature_map: (out): The map of feature tag to feature index.
1292 *
1293 * Fetches the mapping from feature tags to feature indexes for
1294 * the specified script and language.
1295 *
1296 * Since: 8.1.0
1297 **/
1298void
1299hb_ot_layout_collect_features_map (hb_face_t *face,
1300 hb_tag_t table_tag,
1301 unsigned script_index,
1302 unsigned language_index,
1303 hb_map_t *feature_map /* OUT */)
1304{
1305 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1306 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
1307
1308 unsigned int count = l.get_feature_indexes (0, nullptr, nullptr);
1309 feature_map->alloc (count);
1310
1311 for (unsigned int i = 0; i < count; i++)
1312 {
1313 unsigned feature_index = 0;
1314 unsigned feature_count = 1;
1315 l.get_feature_indexes (i, &feature_count, &feature_index);
1316 if (!feature_count)
1317 break;
1318 hb_tag_t feature_tag = g.get_feature_tag (feature_index);
1319 feature_map->set (feature_tag, feature_index);
1320 }
1321}
1322
1323
1324/**
1325 * hb_ot_layout_collect_lookups:
1326 * @face: #hb_face_t to work upon
1327 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1328 * @scripts: (nullable) (array zero-terminated=1): The array of scripts to collect lookups for,
1329 * terminated by %HB_TAG_NONE
1330 * @languages: (nullable) (array zero-terminated=1): The array of languages to collect lookups for,
1331 * terminated by %HB_TAG_NONE
1332 * @features: (nullable) (array zero-terminated=1): The array of features to collect lookups for,
1333 * terminated by %HB_TAG_NONE
1334 * @lookup_indexes: (out): The array of lookup indexes found for the query
1335 *
1336 * Fetches a list of all feature-lookup indexes in the specified face's GSUB
1337 * table or GPOS table, underneath the specified scripts, languages, and
1338 * features. If no list of scripts is provided, all scripts will be queried.
1339 * If no list of languages is provided, all languages will be queried. If no
1340 * list of features is provided, all features will be queried.
1341 *
1342 * Since: 0.9.8
1343 **/
1344void
1345hb_ot_layout_collect_lookups (hb_face_t *face,
1346 hb_tag_t table_tag,
1347 const hb_tag_t *scripts,
1348 const hb_tag_t *languages,
1349 const hb_tag_t *features,
1350 hb_set_t *lookup_indexes /* OUT */)
1351{
1352 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1353
1354 hb_set_t feature_indexes;
1355 hb_ot_layout_collect_features (face, table_tag, scripts, languages, features, &feature_indexes);
1356
1357 for (auto feature_index : feature_indexes)
1358 g.get_feature (feature_index).add_lookup_indexes_to (lookup_indexes);
1359
1360 g.feature_variation_collect_lookups (&feature_indexes, nullptr, lookup_indexes);
1361}
1362
1363
1364#ifndef HB_NO_LAYOUT_COLLECT_GLYPHS
1365/**
1366 * hb_ot_layout_lookup_collect_glyphs:
1367 * @face: #hb_face_t to work upon
1368 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1369 * @lookup_index: The index of the feature lookup to query
1370 * @glyphs_before: (out): Array of glyphs preceding the substitution range
1371 * @glyphs_input: (out): Array of input glyphs that would be substituted by the lookup
1372 * @glyphs_after: (out): Array of glyphs following the substitution range
1373 * @glyphs_output: (out): Array of glyphs that would be the substituted output of the lookup
1374 *
1375 * Fetches a list of all glyphs affected by the specified lookup in the
1376 * specified face's GSUB table or GPOS table.
1377 *
1378 * Since: 0.9.7
1379 **/
1380void
1381hb_ot_layout_lookup_collect_glyphs (hb_face_t *face,
1382 hb_tag_t table_tag,
1383 unsigned int lookup_index,
1384 hb_set_t *glyphs_before, /* OUT. May be NULL */
1385 hb_set_t *glyphs_input, /* OUT. May be NULL */
1386 hb_set_t *glyphs_after, /* OUT. May be NULL */
1387 hb_set_t *glyphs_output /* OUT. May be NULL */)
1388{
1389 OT::hb_collect_glyphs_context_t c (face,
1390 glyphs_before,
1391 glyphs_input,
1392 glyphs_after,
1393 glyphs_output);
1394
1395 switch (table_tag)
1396 {
1397 case HB_OT_TAG_GSUB:
1398 {
1399 const OT::SubstLookup& l = face->table.GSUB->table->get_lookup (lookup_index);
1400 l.collect_glyphs (&c);
1401 return;
1402 }
1403 case HB_OT_TAG_GPOS:
1404 {
1405 const OT::PosLookup& l = face->table.GPOS->table->get_lookup (lookup_index);
1406 l.collect_glyphs (&c);
1407 return;
1408 }
1409 }
1410}
1411#endif
1412
1413
1414/* Variations support */
1415
1416
1417/**
1418 * hb_ot_layout_table_find_feature_variations:
1419 * @face: #hb_face_t to work upon
1420 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1421 * @coords: The variation coordinates to query
1422 * @num_coords: The number of variation coordinates
1423 * @variations_index: (out): The array of feature variations found for the query
1424 *
1425 * Fetches a list of feature variations in the specified face's GSUB table
1426 * or GPOS table, at the specified variation coordinates.
1427 *
1428 * Return value: `true` if feature variations were found, `false` otherwise.
1429 *
1430 * Since: 1.4.0
1431 *
1432 **/
1433hb_bool_t
1434hb_ot_layout_table_find_feature_variations (hb_face_t *face,
1435 hb_tag_t table_tag,
1436 const int *coords,
1437 unsigned int num_coords,
1438 unsigned int *variations_index /* out */)
1439{
1440 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1441
1442 return g.find_variations_index (coords, num_coords, variations_index);
1443}
1444
1445
1446/**
1447 * hb_ot_layout_feature_with_variations_get_lookups:
1448 * @face: #hb_face_t to work upon
1449 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1450 * @feature_index: The index of the feature to query
1451 * @variations_index: The index of the feature variation to query
1452 * @start_offset: offset of the first lookup to retrieve
1453 * @lookup_count: (inout) (optional): Input = the maximum number of lookups to return;
1454 * Output = the actual number of lookups returned (may be zero)
1455 * @lookup_indexes: (out) (array length=lookup_count): The array of lookups found for the query
1456 *
1457 * Fetches a list of all lookups enumerated for the specified feature, in
1458 * the specified face's GSUB table or GPOS table, enabled at the specified
1459 * variations index. The list returned will begin at the offset provided.
1460 *
1461 * Return value: Total number of lookups.
1462 *
1463 * Since: 1.4.0
1464 *
1465 **/
1466unsigned int
1467hb_ot_layout_feature_with_variations_get_lookups (hb_face_t *face,
1468 hb_tag_t table_tag,
1469 unsigned int feature_index,
1470 unsigned int variations_index,
1471 unsigned int start_offset,
1472 unsigned int *lookup_count /* IN/OUT */,
1473 unsigned int *lookup_indexes /* OUT */)
1474{
1475 static_assert ((OT::FeatureVariations::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_VARIATIONS_INDEX), "");
1476 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1477
1478 const OT::Feature &f = g.get_feature_variation (feature_index, variations_index);
1479
1480 return f.get_lookup_indexes (start_offset, lookup_count, lookup_indexes);
1481}
1482
1483
1484/*
1485 * OT::GSUB
1486 */
1487
1488
1489/**
1490 * hb_ot_layout_has_substitution:
1491 * @face: #hb_face_t to work upon
1492 *
1493 * Tests whether the specified face includes any GSUB substitutions.
1494 *
1495 * Return value: `true` if data found, `false` otherwise
1496 *
1497 * Since: 0.6.0
1498 *
1499 **/
1500hb_bool_t
1501hb_ot_layout_has_substitution (hb_face_t *face)
1502{
1503 return face->table.GSUB->table->has_data ();
1504}
1505
1506
1507/**
1508 * hb_ot_layout_lookup_would_substitute:
1509 * @face: #hb_face_t to work upon
1510 * @lookup_index: The index of the lookup to query
1511 * @glyphs: The sequence of glyphs to query for substitution
1512 * @glyphs_length: The length of the glyph sequence
1513 * @zero_context: #hb_bool_t indicating whether pre-/post-context are disallowed
1514 * in substitutions
1515 *
1516 * Tests whether a specified lookup in the specified face would
1517 * trigger a substitution on the given glyph sequence.
1518 *
1519 * Return value: `true` if a substitution would be triggered, `false` otherwise
1520 *
1521 * Since: 0.9.7
1522 **/
1523hb_bool_t
1524hb_ot_layout_lookup_would_substitute (hb_face_t *face,
1525 unsigned int lookup_index,
1526 const hb_codepoint_t *glyphs,
1527 unsigned int glyphs_length,
1528 hb_bool_t zero_context)
1529{
1530 auto &gsub = face->table.GSUB;
1531 if (unlikely (lookup_index >= gsub->lookup_count)) return false;
1532 OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, (bool) zero_context);
1533
1534 const OT::SubstLookup& l = gsub->table->get_lookup (lookup_index);
1535 auto *accel = gsub->get_accel (lookup_index);
1536 return accel && l.would_apply (&c, accel);
1537}
1538
1539
1540/**
1541 * hb_ot_layout_substitute_start:
1542 * @font: #hb_font_t to use
1543 * @buffer: #hb_buffer_t buffer to work upon
1544 *
1545 * Called before substitution lookups are performed, to ensure that glyph
1546 * class and other properties are set on the glyphs in the buffer.
1547 *
1548 **/
1549void
1550hb_ot_layout_substitute_start (hb_font_t *font,
1551 hb_buffer_t *buffer)
1552{
1553 _hb_ot_layout_set_glyph_props (font, buffer);
1554}
1555
1556/**
1557 * hb_ot_layout_lookup_substitute_closure:
1558 * @face: #hb_face_t to work upon
1559 * @lookup_index: index of the feature lookup to query
1560 * @glyphs: (out): Array of glyphs comprising the transitive closure of the lookup
1561 *
1562 * Compute the transitive closure of glyphs needed for a
1563 * specified lookup.
1564 *
1565 * Since: 0.9.7
1566 **/
1567void
1568hb_ot_layout_lookup_substitute_closure (hb_face_t *face,
1569 unsigned int lookup_index,
1570 hb_set_t *glyphs /* OUT */)
1571{
1572 hb_map_t done_lookups_glyph_count;
1573 hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> done_lookups_glyph_set;
1574 OT::hb_closure_context_t c (face, glyphs, &done_lookups_glyph_count, &done_lookups_glyph_set);
1575
1576 const OT::SubstLookup& l = face->table.GSUB->table->get_lookup (lookup_index);
1577
1578 l.closure (&c, lookup_index);
1579}
1580
1581/**
1582 * hb_ot_layout_lookups_substitute_closure:
1583 * @face: #hb_face_t to work upon
1584 * @lookups: The set of lookups to query
1585 * @glyphs: (out): Array of glyphs comprising the transitive closure of the lookups
1586 *
1587 * Compute the transitive closure of glyphs needed for all of the
1588 * provided lookups.
1589 *
1590 * Since: 1.8.1
1591 **/
1592void
1593hb_ot_layout_lookups_substitute_closure (hb_face_t *face,
1594 const hb_set_t *lookups,
1595 hb_set_t *glyphs /* OUT */)
1596{
1597 hb_map_t done_lookups_glyph_count;
1598 hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> done_lookups_glyph_set;
1599 OT::hb_closure_context_t c (face, glyphs, &done_lookups_glyph_count, &done_lookups_glyph_set);
1600 const GSUB& gsub = *face->table.GSUB->table;
1601
1602 unsigned int iteration_count = 0;
1603 unsigned int glyphs_length;
1604 do
1605 {
1606 c.reset_lookup_visit_count ();
1607 glyphs_length = glyphs->get_population ();
1608 if (lookups)
1609 {
1610 for (auto lookup_index : *lookups)
1611 gsub.get_lookup (lookup_index).closure (&c, lookup_index);
1612 }
1613 else
1614 {
1615 for (unsigned int i = 0; i < gsub.get_lookup_count (); i++)
1616 gsub.get_lookup (i).closure (&c, i);
1617 }
1618 } while (iteration_count++ <= HB_CLOSURE_MAX_STAGES &&
1619 glyphs_length != glyphs->get_population ());
1620}
1621
1622/*
1623 * GPOS
1624 */
1625
1626
1627/**
1628 * hb_ot_layout_has_positioning:
1629 * @face: #hb_face_t to work upon
1630 *
1631 * Tests whether the specified face includes any GPOS positioning.
1632 *
1633 * Return value: `true` if the face has GPOS data, `false` otherwise
1634 *
1635 **/
1636hb_bool_t
1637hb_ot_layout_has_positioning (hb_face_t *face)
1638{
1639 return face->table.GPOS->table->has_data ();
1640}
1641
1642/**
1643 * hb_ot_layout_position_start:
1644 * @font: #hb_font_t to use
1645 * @buffer: #hb_buffer_t buffer to work upon
1646 *
1647 * Called before positioning lookups are performed, to ensure that glyph
1648 * attachment types and glyph-attachment chains are set for the glyphs in the buffer.
1649 *
1650 **/
1651void
1652hb_ot_layout_position_start (hb_font_t *font, hb_buffer_t *buffer)
1653{
1654 GPOS::position_start (font, buffer);
1655}
1656
1657
1658/**
1659 * hb_ot_layout_position_finish_advances:
1660 * @font: #hb_font_t to use
1661 * @buffer: #hb_buffer_t buffer to work upon
1662 *
1663 * Called after positioning lookups are performed, to finish glyph advances.
1664 *
1665 **/
1666void
1667hb_ot_layout_position_finish_advances (hb_font_t *font, hb_buffer_t *buffer)
1668{
1669 GPOS::position_finish_advances (font, buffer);
1670}
1671
1672/**
1673 * hb_ot_layout_position_finish_offsets:
1674 * @font: #hb_font_t to use
1675 * @buffer: #hb_buffer_t buffer to work upon
1676 *
1677 * Called after positioning lookups are performed, to finish glyph offsets.
1678 *
1679 **/
1680void
1681hb_ot_layout_position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer)
1682{
1683 GPOS::position_finish_offsets (font, buffer);
1684}
1685
1686
1687#ifndef HB_NO_LAYOUT_FEATURE_PARAMS
1688/**
1689 * hb_ot_layout_get_size_params:
1690 * @face: #hb_face_t to work upon
1691 * @design_size: (out): The design size of the face
1692 * @subfamily_id: (out): The identifier of the face within the font subfamily
1693 * @subfamily_name_id: (out): The ‘name’ table name ID of the face within the font subfamily
1694 * @range_start: (out): The minimum size of the recommended size range for the face
1695 * @range_end: (out): The maximum size of the recommended size range for the face
1696 *
1697 * Fetches optical-size feature data (i.e., the `size` feature from GPOS). Note that
1698 * the subfamily_id and the subfamily name string (accessible via the subfamily_name_id)
1699 * as used here are defined as pertaining only to fonts within a font family that differ
1700 * specifically in their respective size ranges; other ways to differentiate fonts within
1701 * a subfamily are not covered by the `size` feature.
1702 *
1703 * For more information on this distinction, see the [`size` feature documentation](
1704 * https://docs.microsoft.com/en-us/typography/opentype/spec/features_pt#tag-size).
1705 *
1706 * Return value: `true` if data found, `false` otherwise
1707 *
1708 * Since: 0.9.10
1709 **/
1710hb_bool_t
1711hb_ot_layout_get_size_params (hb_face_t *face,
1712 unsigned int *design_size, /* OUT. May be NULL */
1713 unsigned int *subfamily_id, /* OUT. May be NULL */
1714 hb_ot_name_id_t *subfamily_name_id, /* OUT. May be NULL */
1715 unsigned int *range_start, /* OUT. May be NULL */
1716 unsigned int *range_end /* OUT. May be NULL */)
1717{
1718 const GPOS &gpos = *face->table.GPOS->table;
1719 const hb_tag_t tag = HB_TAG ('s','i','z','e');
1720
1721 unsigned int num_features = gpos.get_feature_count ();
1722 for (unsigned int i = 0; i < num_features; i++)
1723 {
1724 if (tag == gpos.get_feature_tag (i))
1725 {
1726 const OT::Feature &f = gpos.get_feature (i);
1727 const OT::FeatureParamsSize &params = f.get_feature_params ().get_size_params (tag);
1728
1729 if (params.designSize)
1730 {
1731 if (design_size) *design_size = params.designSize;
1732 if (subfamily_id) *subfamily_id = params.subfamilyID;
1733 if (subfamily_name_id) *subfamily_name_id = params.subfamilyNameID;
1734 if (range_start) *range_start = params.rangeStart;
1735 if (range_end) *range_end = params.rangeEnd;
1736
1737 return true;
1738 }
1739 }
1740 }
1741
1742 if (design_size) *design_size = 0;
1743 if (subfamily_id) *subfamily_id = 0;
1744 if (subfamily_name_id) *subfamily_name_id = HB_OT_NAME_ID_INVALID;
1745 if (range_start) *range_start = 0;
1746 if (range_end) *range_end = 0;
1747
1748 return false;
1749}
1750
1751
1752/**
1753 * hb_ot_layout_feature_get_name_ids:
1754 * @face: #hb_face_t to work upon
1755 * @table_tag: table tag to query, "GSUB" or "GPOS".
1756 * @feature_index: index of feature to query.
1757 * @label_id: (out) (optional): The ‘name’ table name ID that specifies a string
1758 * for a user-interface label for this feature. (May be NULL.)
1759 * @tooltip_id: (out) (optional): The ‘name’ table name ID that specifies a string
1760 * that an application can use for tooltip text for this
1761 * feature. (May be NULL.)
1762 * @sample_id: (out) (optional): The ‘name’ table name ID that specifies sample text
1763 * that illustrates the effect of this feature. (May be NULL.)
1764 * @num_named_parameters: (out) (optional): Number of named parameters. (May be zero.)
1765 * @first_param_id: (out) (optional): The first ‘name’ table name ID used to specify
1766 * strings for user-interface labels for the feature
1767 * parameters. (Must be zero if numParameters is zero.)
1768 *
1769 * Fetches name indices from feature parameters for "Stylistic Set" ('ssXX') or
1770 * "Character Variant" ('cvXX') features.
1771 *
1772 * Return value: `true` if data found, `false` otherwise
1773 *
1774 * Since: 2.0.0
1775 **/
1776hb_bool_t
1777hb_ot_layout_feature_get_name_ids (hb_face_t *face,
1778 hb_tag_t table_tag,
1779 unsigned int feature_index,
1780 hb_ot_name_id_t *label_id, /* OUT. May be NULL */
1781 hb_ot_name_id_t *tooltip_id, /* OUT. May be NULL */
1782 hb_ot_name_id_t *sample_id, /* OUT. May be NULL */
1783 unsigned int *num_named_parameters, /* OUT. May be NULL */
1784 hb_ot_name_id_t *first_param_id /* OUT. May be NULL */)
1785{
1786 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1787
1788 hb_tag_t feature_tag = g.get_feature_tag (feature_index);
1789 const OT::Feature &f = g.get_feature (feature_index);
1790
1791 const OT::FeatureParams &feature_params = f.get_feature_params ();
1792 if (&feature_params != &Null (OT::FeatureParams))
1793 {
1794 const OT::FeatureParamsStylisticSet& ss_params =
1795 feature_params.get_stylistic_set_params (feature_tag);
1796 if (&ss_params != &Null (OT::FeatureParamsStylisticSet)) /* ssXX */
1797 {
1798 if (label_id) *label_id = ss_params.uiNameID;
1799 // ssXX features don't have the rest
1800 if (tooltip_id) *tooltip_id = HB_OT_NAME_ID_INVALID;
1801 if (sample_id) *sample_id = HB_OT_NAME_ID_INVALID;
1802 if (num_named_parameters) *num_named_parameters = 0;
1803 if (first_param_id) *first_param_id = HB_OT_NAME_ID_INVALID;
1804 return true;
1805 }
1806 const OT::FeatureParamsCharacterVariants& cv_params =
1807 feature_params.get_character_variants_params (feature_tag);
1808 if (&cv_params != &Null (OT::FeatureParamsCharacterVariants)) /* cvXX */
1809 {
1810 if (label_id) *label_id = cv_params.featUILableNameID;
1811 if (tooltip_id) *tooltip_id = cv_params.featUITooltipTextNameID;
1812 if (sample_id) *sample_id = cv_params.sampleTextNameID;
1813 if (num_named_parameters) *num_named_parameters = cv_params.numNamedParameters;
1814 if (first_param_id) *first_param_id = cv_params.firstParamUILabelNameID;
1815 return true;
1816 }
1817 }
1818
1819 if (label_id) *label_id = HB_OT_NAME_ID_INVALID;
1820 if (tooltip_id) *tooltip_id = HB_OT_NAME_ID_INVALID;
1821 if (sample_id) *sample_id = HB_OT_NAME_ID_INVALID;
1822 if (num_named_parameters) *num_named_parameters = 0;
1823 if (first_param_id) *first_param_id = HB_OT_NAME_ID_INVALID;
1824 return false;
1825}
1826/**
1827 * hb_ot_layout_feature_get_characters:
1828 * @face: #hb_face_t to work upon
1829 * @table_tag: table tag to query, "GSUB" or "GPOS".
1830 * @feature_index: index of feature to query.
1831 * @start_offset: offset of the first character to retrieve
1832 * @char_count: (inout) (optional): Input = the maximum number of characters to return;
1833 * Output = the actual number of characters returned (may be zero)
1834 * @characters: (out caller-allocates) (array length=char_count): A buffer pointer.
1835 * The Unicode codepoints of the characters for which this feature provides
1836 * glyph variants.
1837 *
1838 * Fetches a list of the characters defined as having a variant under the specified
1839 * "Character Variant" ("cvXX") feature tag.
1840 *
1841 * Return value: Number of total sample characters in the cvXX feature.
1842 *
1843 * Since: 2.0.0
1844 **/
1845unsigned int
1846hb_ot_layout_feature_get_characters (hb_face_t *face,
1847 hb_tag_t table_tag,
1848 unsigned int feature_index,
1849 unsigned int start_offset,
1850 unsigned int *char_count, /* IN/OUT. May be NULL */
1851 hb_codepoint_t *characters /* OUT. May be NULL */)
1852{
1853 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1854 return g.get_feature (feature_index)
1855 .get_feature_params ()
1856 .get_character_variants_params(g.get_feature_tag (feature_index))
1857 .get_characters (start_offset, char_count, characters);
1858}
1859#endif
1860
1861
1862/*
1863 * Parts of different types are implemented here such that they have direct
1864 * access to GSUB/GPOS lookups.
1865 */
1866
1867
1868struct GSUBProxy
1869{
1870 static constexpr unsigned table_index = 0u;
1871 static constexpr bool always_inplace = false;
1872 typedef OT::SubstLookup Lookup;
1873
1874 GSUBProxy (hb_face_t *face) :
1875 accel (*face->table.GSUB) {}
1876
1877 const GSUB::accelerator_t &accel;
1878};
1879
1880struct GPOSProxy
1881{
1882 static constexpr unsigned table_index = 1u;
1883 static constexpr bool always_inplace = true;
1884 typedef OT::PosLookup Lookup;
1885
1886 GPOSProxy (hb_face_t *face) :
1887 accel (*face->table.GPOS) {}
1888
1889 const GPOS::accelerator_t &accel;
1890};
1891
1892
1893static inline bool
1894apply_forward (OT::hb_ot_apply_context_t *c,
1895 const OT::hb_ot_layout_lookup_accelerator_t &accel,
1896 unsigned subtable_count)
1897{
1898 bool use_cache = accel.cache_enter (c);
1899
1900 bool ret = false;
1901 hb_buffer_t *buffer = c->buffer;
1902 while (buffer->idx < buffer->len && buffer->successful)
1903 {
1904 bool applied = false;
1905 if (accel.digest.may_have (buffer->cur().codepoint) &&
1906 (buffer->cur().mask & c->lookup_mask) &&
1907 c->check_glyph_property (&buffer->cur(), c->lookup_props))
1908 {
1909 applied = accel.apply (c, subtable_count, use_cache);
1910 }
1911
1912 if (applied)
1913 ret = true;
1914 else
1915 (void) buffer->next_glyph ();
1916 }
1917
1918 if (use_cache)
1919 accel.cache_leave (c);
1920
1921 return ret;
1922}
1923
1924static inline bool
1925apply_backward (OT::hb_ot_apply_context_t *c,
1926 const OT::hb_ot_layout_lookup_accelerator_t &accel,
1927 unsigned subtable_count)
1928{
1929 bool ret = false;
1930 hb_buffer_t *buffer = c->buffer;
1931 do
1932 {
1933 if (accel.digest.may_have (buffer->cur().codepoint) &&
1934 (buffer->cur().mask & c->lookup_mask) &&
1935 c->check_glyph_property (&buffer->cur(), c->lookup_props))
1936 ret |= accel.apply (c, subtable_count, false);
1937
1938 /* The reverse lookup doesn't "advance" cursor (for good reason). */
1939 buffer->idx--;
1940
1941 }
1942 while ((int) buffer->idx >= 0);
1943 return ret;
1944}
1945
1946template <typename Proxy>
1947static inline bool
1948apply_string (OT::hb_ot_apply_context_t *c,
1949 const typename Proxy::Lookup &lookup,
1950 const OT::hb_ot_layout_lookup_accelerator_t &accel)
1951{
1952 hb_buffer_t *buffer = c->buffer;
1953 unsigned subtable_count = lookup.get_subtable_count ();
1954
1955 if (unlikely (!buffer->len || !c->lookup_mask))
1956 return false;
1957
1958 bool ret = false;
1959
1960 c->set_lookup_props (lookup.get_props ());
1961
1962 if (likely (!lookup.is_reverse ()))
1963 {
1964 /* in/out forward substitution/positioning */
1965 if (!Proxy::always_inplace)
1966 buffer->clear_output ();
1967
1968 buffer->idx = 0;
1969 ret = apply_forward (c, accel, subtable_count);
1970
1971 if (!Proxy::always_inplace)
1972 buffer->sync ();
1973 }
1974 else
1975 {
1976 /* in-place backward substitution/positioning */
1977 assert (!buffer->have_output);
1978 buffer->idx = buffer->len - 1;
1979 ret = apply_backward (c, accel, subtable_count);
1980 }
1981
1982 return ret;
1983}
1984
1985template <typename Proxy>
1986inline void hb_ot_map_t::apply (const Proxy &proxy,
1987 const hb_ot_shape_plan_t *plan,
1988 hb_font_t *font,
1989 hb_buffer_t *buffer) const
1990{
1991 const unsigned int table_index = proxy.table_index;
1992 unsigned int i = 0;
1993 OT::hb_ot_apply_context_t c (table_index, font, buffer, proxy.accel.get_blob ());
1994 c.set_recurse_func (Proxy::Lookup::template dispatch_recurse_func<OT::hb_ot_apply_context_t>);
1995
1996 for (unsigned int stage_index = 0; stage_index < stages[table_index].length; stage_index++)
1997 {
1998 const stage_map_t *stage = &stages[table_index][stage_index];
1999 for (; i < stage->last_lookup; i++)
2000 {
2001 auto &lookup = lookups[table_index][i];
2002
2003 unsigned int lookup_index = lookup.index;
2004
2005 auto *accel = proxy.accel.get_accel (lookup_index);
2006 if (unlikely (!accel)) continue;
2007
2008 if (buffer->messaging () &&
2009 !buffer->message (font, "start lookup %u feature '%c%c%c%c'", lookup_index, HB_UNTAG (lookup.feature_tag))) continue;
2010
2011 /* c.digest is a digest of all the current glyphs in the buffer
2012 * (plus some past glyphs).
2013 *
2014 * Only try applying the lookup if there is any overlap. */
2015 if (accel->digest.may_have (c.digest))
2016 {
2017 c.set_lookup_index (lookup_index);
2018 c.set_lookup_mask (lookup.mask, false);
2019 c.set_auto_zwj (lookup.auto_zwj, false);
2020 c.set_auto_zwnj (lookup.auto_zwnj, false);
2021 c.set_random (lookup.random);
2022 c.set_per_syllable (lookup.per_syllable, false);
2023 /* apply_string's set_lookup_props initializes the iterators. */
2024
2025 apply_string<Proxy> (&c,
2026 proxy.accel.table->get_lookup (lookup_index),
2027 *accel);
2028 }
2029 else if (buffer->messaging ())
2030 (void) buffer->message (font, "skipped lookup %u feature '%c%c%c%c' because no glyph matches", lookup_index, HB_UNTAG (lookup.feature_tag));
2031
2032 if (buffer->messaging ())
2033 (void) buffer->message (font, "end lookup %u feature '%c%c%c%c'", lookup_index, HB_UNTAG (lookup.feature_tag));
2034 }
2035
2036 if (stage->pause_func)
2037 {
2038 if (stage->pause_func (plan, font, buffer))
2039 {
2040 /* Refresh working buffer digest since buffer changed. */
2041 c.digest = buffer->digest ();
2042 }
2043 }
2044 }
2045}
2046
2047void hb_ot_map_t::substitute (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
2048{
2049 GSUBProxy proxy (font->face);
2050 if (buffer->messaging () &&
2051 !buffer->message (font, "start table GSUB script tag '%c%c%c%c'", HB_UNTAG (chosen_script[0]))) return;
2052 apply (proxy, plan, font, buffer);
2053 if (buffer->messaging ())
2054 (void) buffer->message (font, "end table GSUB script tag '%c%c%c%c'", HB_UNTAG (chosen_script[0]));
2055}
2056
2057void hb_ot_map_t::position (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
2058{
2059 GPOSProxy proxy (font->face);
2060 if (buffer->messaging () &&
2061 !buffer->message (font, "start table GPOS script tag '%c%c%c%c'", HB_UNTAG (chosen_script[1]))) return;
2062 apply (proxy, plan, font, buffer);
2063 if (buffer->messaging ())
2064 (void) buffer->message (font, "end table GPOS script tag '%c%c%c%c'", HB_UNTAG (chosen_script[1]));
2065}
2066
2067void
2068hb_ot_layout_substitute_lookup (OT::hb_ot_apply_context_t *c,
2069 const OT::SubstLookup &lookup,
2070 const OT::hb_ot_layout_lookup_accelerator_t &accel)
2071{
2072 apply_string<GSUBProxy> (c, lookup, accel);
2073}
2074
2075#ifndef HB_NO_BASE
2076
2077static void
2078choose_base_tags (hb_script_t script,
2079 hb_language_t language,
2080 hb_tag_t *script_tag,
2081 hb_tag_t *language_tag)
2082{
2083 hb_tag_t script_tags[HB_OT_MAX_TAGS_PER_SCRIPT];
2084 unsigned script_count = ARRAY_LENGTH (script_tags);
2085
2086 hb_tag_t language_tags[HB_OT_MAX_TAGS_PER_LANGUAGE];
2087 unsigned language_count = ARRAY_LENGTH (language_tags);
2088
2089 hb_ot_tags_from_script_and_language (script, language,
2090 &script_count, script_tags,
2091 &language_count, language_tags);
2092
2093 *script_tag = script_count ? script_tags[script_count - 1] : HB_OT_TAG_DEFAULT_SCRIPT;
2094 *language_tag = language_count ? language_tags[language_count - 1] : HB_OT_TAG_DEFAULT_LANGUAGE;
2095}
2096
2097/**
2098 * hb_ot_layout_get_font_extents:
2099 * @font: a font
2100 * @direction: text direction.
2101 * @script_tag: script tag.
2102 * @language_tag: language tag.
2103 * @extents: (out) (nullable): font extents if found.
2104 *
2105 * Fetches script/language-specific font extents. These values are
2106 * looked up in the `BASE` table's `MinMax` records.
2107 *
2108 * If no such extents are found, the default extents for the font are
2109 * fetched. As such, the return value of this function can for the
2110 * most part be ignored. Note that the per-script/language extents
2111 * do not have a line-gap value, and the line-gap is set to zero in
2112 * that case.
2113 *
2114 * Return value: `true` if found script/language-specific font extents.
2115 *
2116 * Since: 8.0.0
2117 **/
2118hb_bool_t
2119hb_ot_layout_get_font_extents (hb_font_t *font,
2120 hb_direction_t direction,
2121 hb_tag_t script_tag,
2122 hb_tag_t language_tag,
2123 hb_font_extents_t *extents)
2124{
2125 hb_position_t min, max;
2126 if (font->face->table.BASE->get_min_max (font, direction, script_tag, language_tag, HB_TAG_NONE,
2127 &min, &max))
2128 {
2129 if (extents)
2130 {
2131 extents->ascender = max;
2132 extents->descender = min;
2133 extents->line_gap = 0;
2134 }
2135 return true;
2136 }
2137
2138 hb_font_get_extents_for_direction (font, direction, extents);
2139 return false;
2140}
2141
2142/**
2143 * hb_ot_layout_get_font_extents2:
2144 * @font: a font
2145 * @direction: text direction.
2146 * @script: script.
2147 * @language: (nullable): language.
2148 * @extents: (out) (nullable): font extents if found.
2149 *
2150 * Fetches script/language-specific font extents. These values are
2151 * looked up in the `BASE` table's `MinMax` records.
2152 *
2153 * If no such extents are found, the default extents for the font are
2154 * fetched. As such, the return value of this function can for the
2155 * most part be ignored. Note that the per-script/language extents
2156 * do not have a line-gap value, and the line-gap is set to zero in
2157 * that case.
2158 *
2159 * This function is like hb_ot_layout_get_font_extents() but takes
2160 * #hb_script_t and #hb_language_t instead of OpenType #hb_tag_t.
2161 *
2162 * Return value: `true` if found script/language-specific font extents.
2163 *
2164 * Since: 8.0.0
2165 **/
2166hb_bool_t
2167hb_ot_layout_get_font_extents2 (hb_font_t *font,
2168 hb_direction_t direction,
2169 hb_script_t script,
2170 hb_language_t language,
2171 hb_font_extents_t *extents)
2172{
2173 hb_tag_t script_tag, language_tag;
2174 choose_base_tags (script, language, &script_tag, &language_tag);
2175 return hb_ot_layout_get_font_extents (font,
2176 direction,
2177 script_tag,
2178 language_tag,
2179 extents);
2180}
2181
2182/**
2183 * hb_ot_layout_get_horizontal_baseline_tag_for_script:
2184 * @script: a script tag.
2185 *
2186 * Fetches the dominant horizontal baseline tag used by @script.
2187 *
2188 * Return value: dominant baseline tag for the @script.
2189 *
2190 * Since: 4.0.0
2191 **/
2192hb_ot_layout_baseline_tag_t
2193hb_ot_layout_get_horizontal_baseline_tag_for_script (hb_script_t script)
2194{
2195 /* Keep in sync with hb_ot_layout_get_baseline_with_fallback */
2196 switch ((int) script)
2197 {
2198 /* Unicode-1.1 additions */
2199 case HB_SCRIPT_BENGALI:
2200 case HB_SCRIPT_DEVANAGARI:
2201 case HB_SCRIPT_GUJARATI:
2202 case HB_SCRIPT_GURMUKHI:
2203 /* Unicode-2.0 additions */
2204 case HB_SCRIPT_TIBETAN:
2205 /* Unicode-4.0 additions */
2206 case HB_SCRIPT_LIMBU:
2207 /* Unicode-4.1 additions */
2208 case HB_SCRIPT_SYLOTI_NAGRI:
2209 /* Unicode-5.0 additions */
2210 case HB_SCRIPT_PHAGS_PA:
2211 /* Unicode-5.2 additions */
2212 case HB_SCRIPT_MEETEI_MAYEK:
2213 /* Unicode-6.1 additions */
2214 case HB_SCRIPT_SHARADA:
2215 case HB_SCRIPT_TAKRI:
2216 /* Unicode-7.0 additions */
2217 case HB_SCRIPT_MODI:
2218 case HB_SCRIPT_SIDDHAM:
2219 case HB_SCRIPT_TIRHUTA:
2220 /* Unicode-9.0 additions */
2221 case HB_SCRIPT_MARCHEN:
2222 case HB_SCRIPT_NEWA:
2223 /* Unicode-10.0 additions */
2224 case HB_SCRIPT_SOYOMBO:
2225 case HB_SCRIPT_ZANABAZAR_SQUARE:
2226 /* Unicode-11.0 additions */
2227 case HB_SCRIPT_DOGRA:
2228 case HB_SCRIPT_GUNJALA_GONDI:
2229 /* Unicode-12.0 additions */
2230 case HB_SCRIPT_NANDINAGARI:
2231 return HB_OT_LAYOUT_BASELINE_TAG_HANGING;
2232
2233 /* Unicode-1.1 additions */
2234 case HB_SCRIPT_HANGUL:
2235 case HB_SCRIPT_HAN:
2236 case HB_SCRIPT_HIRAGANA:
2237 case HB_SCRIPT_KATAKANA:
2238 /* Unicode-3.0 additions */
2239 case HB_SCRIPT_BOPOMOFO:
2240 /* Unicode-9.0 additions */
2241 case HB_SCRIPT_TANGUT:
2242 /* Unicode-10.0 additions */
2243 case HB_SCRIPT_NUSHU:
2244 /* Unicode-13.0 additions */
2245 case HB_SCRIPT_KHITAN_SMALL_SCRIPT:
2246 return HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT;
2247
2248 default:
2249 return HB_OT_LAYOUT_BASELINE_TAG_ROMAN;
2250 }
2251}
2252
2253/**
2254 * hb_ot_layout_get_baseline:
2255 * @font: a font
2256 * @baseline_tag: a baseline tag
2257 * @direction: text direction.
2258 * @script_tag: script tag.
2259 * @language_tag: language tag, currently unused.
2260 * @coord: (out) (nullable): baseline value if found.
2261 *
2262 * Fetches a baseline value from the face.
2263 *
2264 * Return value: `true` if found baseline value in the font.
2265 *
2266 * Since: 2.6.0
2267 **/
2268hb_bool_t
2269hb_ot_layout_get_baseline (hb_font_t *font,
2270 hb_ot_layout_baseline_tag_t baseline_tag,
2271 hb_direction_t direction,
2272 hb_tag_t script_tag,
2273 hb_tag_t language_tag,
2274 hb_position_t *coord /* OUT. May be NULL. */)
2275{
2276 return font->face->table.BASE->get_baseline (font, baseline_tag, direction, script_tag, language_tag, coord);
2277}
2278
2279/**
2280 * hb_ot_layout_get_baseline2:
2281 * @font: a font
2282 * @baseline_tag: a baseline tag
2283 * @direction: text direction.
2284 * @script: script.
2285 * @language: (nullable): language, currently unused.
2286 * @coord: (out) (nullable): baseline value if found.
2287 *
2288 * Fetches a baseline value from the face.
2289 *
2290 * This function is like hb_ot_layout_get_baseline() but takes
2291 * #hb_script_t and #hb_language_t instead of OpenType #hb_tag_t.
2292 *
2293 * Return value: `true` if found baseline value in the font.
2294 *
2295 * Since: 8.0.0
2296 **/
2297hb_bool_t
2298hb_ot_layout_get_baseline2 (hb_font_t *font,
2299 hb_ot_layout_baseline_tag_t baseline_tag,
2300 hb_direction_t direction,
2301 hb_script_t script,
2302 hb_language_t language,
2303 hb_position_t *coord /* OUT. May be NULL. */)
2304{
2305 hb_tag_t script_tag, language_tag;
2306 choose_base_tags (script, language, &script_tag, &language_tag);
2307 return hb_ot_layout_get_baseline (font,
2308 baseline_tag,
2309 direction,
2310 script_tag,
2311 language_tag,
2312 coord);
2313}
2314
2315/**
2316 * hb_ot_layout_get_baseline_with_fallback:
2317 * @font: a font
2318 * @baseline_tag: a baseline tag
2319 * @direction: text direction.
2320 * @script_tag: script tag.
2321 * @language_tag: language tag, currently unused.
2322 * @coord: (out): baseline value if found.
2323 *
2324 * Fetches a baseline value from the face, and synthesizes
2325 * it if the font does not have it.
2326 *
2327 * Since: 4.0.0
2328 **/
2329void
2330hb_ot_layout_get_baseline_with_fallback (hb_font_t *font,
2331 hb_ot_layout_baseline_tag_t baseline_tag,
2332 hb_direction_t direction,
2333 hb_tag_t script_tag,
2334 hb_tag_t language_tag,
2335 hb_position_t *coord /* OUT */)
2336{
2337 if (hb_ot_layout_get_baseline (font,
2338 baseline_tag,
2339 direction,
2340 script_tag,
2341 language_tag,
2342 coord))
2343 return;
2344
2345 /* Synthesize missing baselines.
2346 * See https://www.w3.org/TR/css-inline-3/#baseline-synthesis-fonts
2347 */
2348 switch (baseline_tag)
2349 {
2350 case HB_OT_LAYOUT_BASELINE_TAG_ROMAN:
2351 *coord = 0; // FIXME origin ?
2352 break;
2353
2354 case HB_OT_LAYOUT_BASELINE_TAG_MATH:
2355 {
2356 hb_codepoint_t glyph;
2357 hb_glyph_extents_t extents;
2358 if (HB_DIRECTION_IS_HORIZONTAL (direction) &&
2359 (hb_font_get_nominal_glyph (font, 0x2212u, &glyph) ||
2360 hb_font_get_nominal_glyph (font, '-', &glyph)) &&
2361 hb_font_get_glyph_extents (font, glyph, &extents))
2362 {
2363 *coord = extents.y_bearing + extents.height / 2;
2364 }
2365 else
2366 {
2367 hb_position_t x_height = font->y_scale / 2;
2368#ifndef HB_NO_METRICS
2369 hb_ot_metrics_get_position_with_fallback (font, HB_OT_METRICS_TAG_X_HEIGHT, &x_height);
2370#endif
2371 *coord = x_height / 2;
2372 }
2373 }
2374 break;
2375
2376 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT:
2377 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT:
2378 {
2379 hb_position_t embox_top, embox_bottom;
2380
2381 hb_ot_layout_get_baseline_with_fallback (font,
2382 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT,
2383 direction,
2384 script_tag,
2385 language_tag,
2386 &embox_top);
2387 hb_ot_layout_get_baseline_with_fallback (font,
2388 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
2389 direction,
2390 script_tag,
2391 language_tag,
2392 &embox_bottom);
2393
2394 if (baseline_tag == HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT)
2395 *coord = embox_top + (embox_bottom - embox_top) / 10;
2396 else
2397 *coord = embox_bottom + (embox_top - embox_bottom) / 10;
2398 }
2399 break;
2400
2401 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT:
2402 if (hb_ot_layout_get_baseline (font,
2403 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
2404 direction,
2405 script_tag,
2406 language_tag,
2407 coord))
2408 *coord += HB_DIRECTION_IS_HORIZONTAL (direction) ? font->y_scale : font->x_scale;
2409 else
2410 {
2411 hb_font_extents_t font_extents;
2412 hb_font_get_extents_for_direction (font, direction, &font_extents);
2413 *coord = font_extents.ascender;
2414 }
2415 break;
2416
2417 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT:
2418 if (hb_ot_layout_get_baseline (font,
2419 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT,
2420 direction,
2421 script_tag,
2422 language_tag,
2423 coord))
2424 *coord -= HB_DIRECTION_IS_HORIZONTAL (direction) ? font->y_scale : font->x_scale;
2425 else
2426 {
2427 hb_font_extents_t font_extents;
2428 hb_font_get_extents_for_direction (font, direction, &font_extents);
2429 *coord = font_extents.descender;
2430 }
2431 break;
2432
2433 case HB_OT_LAYOUT_BASELINE_TAG_HANGING:
2434 if (HB_DIRECTION_IS_HORIZONTAL (direction))
2435 {
2436 hb_codepoint_t ch;
2437 hb_codepoint_t glyph;
2438 hb_glyph_extents_t extents;
2439
2440 /* Keep in sync with hb_ot_layout_get_horizontal_baseline_for_script */
2441 switch ((int) script_tag)
2442 {
2443 /* Unicode-1.1 additions */
2444 case HB_SCRIPT_BENGALI: ch = 0x0995u; break;
2445 case HB_SCRIPT_DEVANAGARI: ch = 0x0915u; break;
2446 case HB_SCRIPT_GUJARATI: ch = 0x0a95u; break;
2447 case HB_SCRIPT_GURMUKHI: ch = 0x0a15u; break;
2448 /* Unicode-2.0 additions */
2449 case HB_SCRIPT_TIBETAN: ch = 0x0f40u; break;
2450 /* Unicode-4.0 additions */
2451 case HB_SCRIPT_LIMBU: ch = 0x1901u; break;
2452 /* Unicode-4.1 additions */
2453 case HB_SCRIPT_SYLOTI_NAGRI: ch = 0xa807u; break;
2454 /* Unicode-5.0 additions */
2455 case HB_SCRIPT_PHAGS_PA: ch = 0xa840u; break;
2456 /* Unicode-5.2 additions */
2457 case HB_SCRIPT_MEETEI_MAYEK: ch = 0xabc0u; break;
2458 /* Unicode-6.1 additions */
2459 case HB_SCRIPT_SHARADA: ch = 0x11191u; break;
2460 case HB_SCRIPT_TAKRI: ch = 0x1168cu; break;
2461 /* Unicode-7.0 additions */
2462 case HB_SCRIPT_MODI: ch = 0x1160eu;break;
2463 case HB_SCRIPT_SIDDHAM: ch = 0x11590u; break;
2464 case HB_SCRIPT_TIRHUTA: ch = 0x1148fu; break;
2465 /* Unicode-9.0 additions */
2466 case HB_SCRIPT_MARCHEN: ch = 0x11c72u; break;
2467 case HB_SCRIPT_NEWA: ch = 0x1140eu; break;
2468 /* Unicode-10.0 additions */
2469 case HB_SCRIPT_SOYOMBO: ch = 0x11a5cu; break;
2470 case HB_SCRIPT_ZANABAZAR_SQUARE: ch = 0x11a0bu; break;
2471 /* Unicode-11.0 additions */
2472 case HB_SCRIPT_DOGRA: ch = 0x1180au; break;
2473 case HB_SCRIPT_GUNJALA_GONDI: ch = 0x11d6cu; break;
2474 /* Unicode-12.0 additions */
2475 case HB_SCRIPT_NANDINAGARI: ch = 0x119b0u; break;
2476 default: ch = 0; break;
2477 }
2478
2479 if (ch &&
2480 hb_font_get_nominal_glyph (font, ch, &glyph) &&
2481 hb_font_get_glyph_extents (font, glyph, &extents))
2482 *coord = extents.y_bearing;
2483 else
2484 *coord = font->y_scale * 6 / 10; // FIXME makes assumptions about origin
2485 }
2486 else
2487 *coord = font->x_scale * 6 / 10; // FIXME makes assumptions about origin
2488 break;
2489
2490 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_CENTRAL:
2491 {
2492 hb_position_t top, bottom;
2493 hb_ot_layout_get_baseline_with_fallback (font,
2494 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT,
2495 direction,
2496 script_tag,
2497 language_tag,
2498 &top);
2499 hb_ot_layout_get_baseline_with_fallback (font,
2500 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
2501 direction,
2502 script_tag,
2503 language_tag,
2504 &bottom);
2505 *coord = (top + bottom) / 2;
2506
2507 }
2508 break;
2509
2510 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_CENTRAL:
2511 {
2512 hb_position_t top, bottom;
2513 hb_ot_layout_get_baseline_with_fallback (font,
2514 HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT,
2515 direction,
2516 script_tag,
2517 language_tag,
2518 &top);
2519 hb_ot_layout_get_baseline_with_fallback (font,
2520 HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT,
2521 direction,
2522 script_tag,
2523 language_tag,
2524 &bottom);
2525 *coord = (top + bottom) / 2;
2526
2527 }
2528 break;
2529
2530 case _HB_OT_LAYOUT_BASELINE_TAG_MAX_VALUE:
2531 default:
2532 *coord = 0;
2533 break;
2534 }
2535}
2536
2537/**
2538 * hb_ot_layout_get_baseline_with_fallback2:
2539 * @font: a font
2540 * @baseline_tag: a baseline tag
2541 * @direction: text direction.
2542 * @script: script.
2543 * @language: (nullable): language, currently unused.
2544 * @coord: (out): baseline value if found.
2545 *
2546 * Fetches a baseline value from the face, and synthesizes
2547 * it if the font does not have it.
2548 *
2549 * This function is like hb_ot_layout_get_baseline_with_fallback() but takes
2550 * #hb_script_t and #hb_language_t instead of OpenType #hb_tag_t.
2551 *
2552 * Since: 8.0.0
2553 **/
2554void
2555hb_ot_layout_get_baseline_with_fallback2 (hb_font_t *font,
2556 hb_ot_layout_baseline_tag_t baseline_tag,
2557 hb_direction_t direction,
2558 hb_script_t script,
2559 hb_language_t language,
2560 hb_position_t *coord /* OUT */)
2561{
2562 hb_tag_t script_tag, language_tag;
2563 choose_base_tags (script, language, &script_tag, &language_tag);
2564 hb_ot_layout_get_baseline_with_fallback (font,
2565 baseline_tag,
2566 direction,
2567 script_tag,
2568 language_tag,
2569 coord);
2570}
2571
2572#endif
2573
2574
2575struct hb_get_glyph_alternates_dispatch_t :
2576 hb_dispatch_context_t<hb_get_glyph_alternates_dispatch_t, unsigned>
2577{
2578 static return_t default_return_value () { return 0; }
2579 bool stop_sublookup_iteration (return_t r) const { return r; }
2580
2581 private:
2582 template <typename T, typename ...Ts> auto
2583 _dispatch (const T &obj, hb_priority<1>, Ts&&... ds) HB_AUTO_RETURN
2584 ( obj.get_glyph_alternates (std::forward<Ts> (ds)...) )
2585 template <typename T, typename ...Ts> auto
2586 _dispatch (const T &obj, hb_priority<0>, Ts&&... ds) HB_AUTO_RETURN
2587 ( default_return_value () )
2588 public:
2589 template <typename T, typename ...Ts> auto
2590 dispatch (const T &obj, Ts&&... ds) HB_AUTO_RETURN
2591 ( _dispatch (obj, hb_prioritize, std::forward<Ts> (ds)...) )
2592};
2593
2594#ifndef HB_NO_LAYOUT_RARELY_USED
2595/**
2596 * hb_ot_layout_lookup_get_glyph_alternates:
2597 * @face: a face.
2598 * @lookup_index: index of the feature lookup to query.
2599 * @glyph: a glyph id.
2600 * @start_offset: starting offset.
2601 * @alternate_count: (inout) (optional): Input = the maximum number of alternate glyphs to return;
2602 * Output = the actual number of alternate glyphs returned (may be zero).
2603 * @alternate_glyphs: (out caller-allocates) (array length=alternate_count): A glyphs buffer.
2604 * Alternate glyphs associated with the glyph id.
2605 *
2606 * Fetches alternates of a glyph from a given GSUB lookup index.
2607 *
2608 * Return value: Total number of alternates found in the specific lookup index for the given glyph id.
2609 *
2610 * Since: 2.6.8
2611 **/
2612HB_EXTERN unsigned
2613hb_ot_layout_lookup_get_glyph_alternates (hb_face_t *face,
2614 unsigned lookup_index,
2615 hb_codepoint_t glyph,
2616 unsigned start_offset,
2617 unsigned *alternate_count /* IN/OUT. May be NULL. */,
2618 hb_codepoint_t *alternate_glyphs /* OUT. May be NULL. */)
2619{
2620 hb_get_glyph_alternates_dispatch_t c;
2621 const OT::SubstLookup &lookup = face->table.GSUB->table->get_lookup (lookup_index);
2622 auto ret = lookup.dispatch (&c, glyph, start_offset, alternate_count, alternate_glyphs);
2623 if (!ret && alternate_count) *alternate_count = 0;
2624 return ret;
2625}
2626
2627
2628struct hb_position_single_dispatch_t :
2629 hb_dispatch_context_t<hb_position_single_dispatch_t, bool>
2630{
2631 static return_t default_return_value () { return false; }
2632 bool stop_sublookup_iteration (return_t r) const { return r; }
2633
2634 private:
2635 template <typename T, typename ...Ts> auto
2636 _dispatch (const T &obj, hb_priority<1>, Ts&&... ds) HB_AUTO_RETURN
2637 ( obj.position_single (std::forward<Ts> (ds)...) )
2638 template <typename T, typename ...Ts> auto
2639 _dispatch (const T &obj, hb_priority<0>, Ts&&... ds) HB_AUTO_RETURN
2640 ( default_return_value () )
2641 public:
2642 template <typename T, typename ...Ts> auto
2643 dispatch (const T &obj, Ts&&... ds) HB_AUTO_RETURN
2644 ( _dispatch (obj, hb_prioritize, std::forward<Ts> (ds)...) )
2645};
2646
2647/**
2648 * hb_ot_layout_lookup_get_optical_bound:
2649 * @font: a font.
2650 * @lookup_index: index of the feature lookup to query.
2651 * @direction: edge of the glyph to query.
2652 * @glyph: a glyph id.
2653 *
2654 * Fetches the optical bound of a glyph positioned at the margin of text.
2655 * The direction identifies which edge of the glyph to query.
2656 *
2657 * Return value: Adjustment value. Negative values mean the glyph will stick out of the margin.
2658 *
2659 * Since: 5.3.0
2660 **/
2661hb_position_t
2662hb_ot_layout_lookup_get_optical_bound (hb_font_t *font,
2663 unsigned lookup_index,
2664 hb_direction_t direction,
2665 hb_codepoint_t glyph)
2666{
2667 const OT::PosLookup &lookup = font->face->table.GPOS->table->get_lookup (lookup_index);
2668 hb_blob_t *blob = font->face->table.GPOS->get_blob ();
2669 hb_glyph_position_t pos = {0};
2670 hb_position_single_dispatch_t c;
2671 lookup.dispatch (&c, font, blob, direction, glyph, pos);
2672 hb_position_t ret = 0;
2673 switch (direction)
2674 {
2675 case HB_DIRECTION_LTR:
2676 ret = pos.x_offset;
2677 break;
2678 case HB_DIRECTION_RTL:
2679 ret = pos.x_advance - pos.x_offset;
2680 break;
2681 case HB_DIRECTION_TTB:
2682 ret = pos.y_offset;
2683 break;
2684 case HB_DIRECTION_BTT:
2685 ret = pos.y_advance - pos.y_offset;
2686 break;
2687 case HB_DIRECTION_INVALID:
2688 default:
2689 break;
2690 }
2691 return ret;
2692}
2693#endif
2694
2695
2696#endif
2697