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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
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
57 using OT::Layout::GSUB;
58 using 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 **/
68
69
70 /*
71 * kern
72 */
73
74 #ifndef HB_NO_OT_KERN
75 /**
76 * hb_ot_layout_has_kerning:
77 * @face: The #hb_face_t to work on
78 *
79 * Tests whether a face includes any kerning data in the 'kern' table.
80 * Does NOT test for kerning lookups in the GPOS table.
81 *
82 * Return value: `true` if data found, `false` otherwise
83 *
84 **/
85 bool
86 hb_ot_layout_has_kerning (hb_face_t *face)
87 {
88 return face->table.kern->has_data ();
89 }
90
91 /**
92 * hb_ot_layout_has_machine_kerning:
93 * @face: The #hb_face_t to work on
94 *
95 * Tests whether a face includes any state-machine kerning in the 'kern' table.
96 * Does NOT examine the GPOS table.
97 *
98 * Return value: `true` if data found, `false` otherwise
99 *
100 **/
101 bool
102 hb_ot_layout_has_machine_kerning (hb_face_t *face)
103 {
104 return face->table.kern->has_state_machine ();
105 }
106
107 /**
108 * hb_ot_layout_has_cross_kerning:
109 * @face: The #hb_face_t to work on
110 *
111 * Tests whether a face has any cross-stream kerning (i.e., kerns
112 * that make adjustments perpendicular to the direction of the text
113 * flow: Y adjustments in horizontal text or X adjustments in
114 * vertical text) in the 'kern' table.
115 *
116 * Does NOT examine the GPOS table.
117 *
118 * Return value: `true` is data found, `false` otherwise
119 *
120 **/
121 bool
122 hb_ot_layout_has_cross_kerning (hb_face_t *face)
123 {
124 return face->table.kern->has_cross_stream ();
125 }
126
127 void
128 hb_ot_layout_kern (const hb_ot_shape_plan_t *plan,
129 hb_font_t *font,
130 hb_buffer_t *buffer)
131 {
132 hb_blob_t *blob = font->face->table.kern.get_blob ();
133 const AAT::kern& kern = *blob->as<AAT::kern> ();
134
135 AAT::hb_aat_apply_context_t c (plan, font, buffer, blob);
136
137 if (!buffer->message (font, "start table kern")) return;
138 kern.apply (&c);
139 (void) buffer->message (font, "end table kern");
140 }
141 #endif
142
143
144 /*
145 * GDEF
146 */
147
148 bool
149 OT::GDEF::is_blocklisted (hb_blob_t *blob,
150 hb_face_t *face) const
151 {
152 #ifdef HB_NO_OT_LAYOUT_BLOCKLIST
153 return false;
154 #endif
155 /* The ugly business of blocklisting individual fonts' tables happen here!
156 * See this thread for why we finally had to bend in and do this:
157 * https://lists.freedesktop.org/archives/harfbuzz/2016-February/005489.html
158 *
159 * In certain versions of Times New Roman Italic and Bold Italic,
160 * ASCII double quotation mark U+0022 has wrong glyph class 3 (mark)
161 * in GDEF. Many versions of Tahoma have bad GDEF tables that
162 * incorrectly classify some spacing marks such as certain IPA
163 * symbols as glyph class 3. So do older versions of Microsoft
164 * Himalaya, and the version of Cantarell shipped by Ubuntu 16.04.
165 *
166 * Nuke the GDEF tables of to avoid unwanted width-zeroing.
167 *
168 * See https://bugzilla.mozilla.org/show_bug.cgi?id=1279925
169 * https://bugzilla.mozilla.org/show_bug.cgi?id=1279693
170 * https://bugzilla.mozilla.org/show_bug.cgi?id=1279875
171 */
172 switch HB_CODEPOINT_ENCODE3(blob->length,
173 face->table.GSUB->table.get_length (),
174 face->table.GPOS->table.get_length ())
175 {
176 /* sha1sum:c5ee92f0bca4bfb7d06c4d03e8cf9f9cf75d2e8a Windows 7? timesi.ttf */
177 case HB_CODEPOINT_ENCODE3 (442, 2874, 42038):
178 /* sha1sum:37fc8c16a0894ab7b749e35579856c73c840867b Windows 7? timesbi.ttf */
179 case HB_CODEPOINT_ENCODE3 (430, 2874, 40662):
180 /* sha1sum:19fc45110ea6cd3cdd0a5faca256a3797a069a80 Windows 7 timesi.ttf */
181 case HB_CODEPOINT_ENCODE3 (442, 2874, 39116):
182 /* sha1sum:6d2d3c9ed5b7de87bc84eae0df95ee5232ecde26 Windows 7 timesbi.ttf */
183 case HB_CODEPOINT_ENCODE3 (430, 2874, 39374):
184 /* sha1sum:8583225a8b49667c077b3525333f84af08c6bcd8 OS X 10.11.3 Times New Roman Italic.ttf */
185 case HB_CODEPOINT_ENCODE3 (490, 3046, 41638):
186 /* sha1sum:ec0f5a8751845355b7c3271d11f9918a966cb8c9 OS X 10.11.3 Times New Roman Bold Italic.ttf */
187 case HB_CODEPOINT_ENCODE3 (478, 3046, 41902):
188 /* sha1sum:96eda93f7d33e79962451c6c39a6b51ee893ce8c tahoma.ttf from Windows 8 */
189 case HB_CODEPOINT_ENCODE3 (898, 12554, 46470):
190 /* sha1sum:20928dc06014e0cd120b6fc942d0c3b1a46ac2bc tahomabd.ttf from Windows 8 */
191 case HB_CODEPOINT_ENCODE3 (910, 12566, 47732):
192 /* sha1sum:4f95b7e4878f60fa3a39ca269618dfde9721a79e tahoma.ttf from Windows 8.1 */
193 case HB_CODEPOINT_ENCODE3 (928, 23298, 59332):
194 /* sha1sum:6d400781948517c3c0441ba42acb309584b73033 tahomabd.ttf from Windows 8.1 */
195 case HB_CODEPOINT_ENCODE3 (940, 23310, 60732):
196 /* tahoma.ttf v6.04 from Windows 8.1 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
197 case HB_CODEPOINT_ENCODE3 (964, 23836, 60072):
198 /* tahomabd.ttf v6.04 from Windows 8.1 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
199 case HB_CODEPOINT_ENCODE3 (976, 23832, 61456):
200 /* sha1sum:e55fa2dfe957a9f7ec26be516a0e30b0c925f846 tahoma.ttf from Windows 10 */
201 case HB_CODEPOINT_ENCODE3 (994, 24474, 60336):
202 /* sha1sum:7199385abb4c2cc81c83a151a7599b6368e92343 tahomabd.ttf from Windows 10 */
203 case HB_CODEPOINT_ENCODE3 (1006, 24470, 61740):
204 /* tahoma.ttf v6.91 from Windows 10 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
205 case HB_CODEPOINT_ENCODE3 (1006, 24576, 61346):
206 /* tahomabd.ttf v6.91 from Windows 10 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
207 case HB_CODEPOINT_ENCODE3 (1018, 24572, 62828):
208 /* sha1sum:b9c84d820c49850d3d27ec498be93955b82772b5 tahoma.ttf from Windows 10 AU */
209 case HB_CODEPOINT_ENCODE3 (1006, 24576, 61352):
210 /* sha1sum:2bdfaab28174bdadd2f3d4200a30a7ae31db79d2 tahomabd.ttf from Windows 10 AU */
211 case HB_CODEPOINT_ENCODE3 (1018, 24572, 62834):
212 /* sha1sum:b0d36cf5a2fbe746a3dd277bffc6756a820807a7 Tahoma.ttf from Mac OS X 10.9 */
213 case HB_CODEPOINT_ENCODE3 (832, 7324, 47162):
214 /* sha1sum:12fc4538e84d461771b30c18b5eb6bd434e30fba Tahoma Bold.ttf from Mac OS X 10.9 */
215 case HB_CODEPOINT_ENCODE3 (844, 7302, 45474):
216 /* sha1sum:eb8afadd28e9cf963e886b23a30b44ab4fd83acc himalaya.ttf from Windows 7 */
217 case HB_CODEPOINT_ENCODE3 (180, 13054, 7254):
218 /* sha1sum:73da7f025b238a3f737aa1fde22577a6370f77b0 himalaya.ttf from Windows 8 */
219 case HB_CODEPOINT_ENCODE3 (192, 12638, 7254):
220 /* sha1sum:6e80fd1c0b059bbee49272401583160dc1e6a427 himalaya.ttf from Windows 8.1 */
221 case HB_CODEPOINT_ENCODE3 (192, 12690, 7254):
222 /* 8d9267aea9cd2c852ecfb9f12a6e834bfaeafe44 cantarell-fonts-0.0.21/otf/Cantarell-Regular.otf */
223 /* 983988ff7b47439ab79aeaf9a45bd4a2c5b9d371 cantarell-fonts-0.0.21/otf/Cantarell-Oblique.otf */
224 case HB_CODEPOINT_ENCODE3 (188, 248, 3852):
225 /* 2c0c90c6f6087ffbfea76589c93113a9cbb0e75f cantarell-fonts-0.0.21/otf/Cantarell-Bold.otf */
226 /* 55461f5b853c6da88069ffcdf7f4dd3f8d7e3e6b cantarell-fonts-0.0.21/otf/Cantarell-Bold-Oblique.otf */
227 case HB_CODEPOINT_ENCODE3 (188, 264, 3426):
228 /* d125afa82a77a6475ac0e74e7c207914af84b37a padauk-2.80/Padauk.ttf RHEL 7.2 */
229 case HB_CODEPOINT_ENCODE3 (1058, 47032, 11818):
230 /* 0f7b80437227b90a577cc078c0216160ae61b031 padauk-2.80/Padauk-Bold.ttf RHEL 7.2*/
231 case HB_CODEPOINT_ENCODE3 (1046, 47030, 12600):
232 /* d3dde9aa0a6b7f8f6a89ef1002e9aaa11b882290 padauk-2.80/Padauk.ttf Ubuntu 16.04 */
233 case HB_CODEPOINT_ENCODE3 (1058, 71796, 16770):
234 /* 5f3c98ccccae8a953be2d122c1b3a77fd805093f padauk-2.80/Padauk-Bold.ttf Ubuntu 16.04 */
235 case HB_CODEPOINT_ENCODE3 (1046, 71790, 17862):
236 /* 6c93b63b64e8b2c93f5e824e78caca555dc887c7 padauk-2.80/Padauk-book.ttf */
237 case HB_CODEPOINT_ENCODE3 (1046, 71788, 17112):
238 /* d89b1664058359b8ec82e35d3531931125991fb9 padauk-2.80/Padauk-bookbold.ttf */
239 case HB_CODEPOINT_ENCODE3 (1058, 71794, 17514):
240 /* 824cfd193aaf6234b2b4dc0cf3c6ef576c0d00ef padauk-3.0/Padauk-book.ttf */
241 case HB_CODEPOINT_ENCODE3 (1330, 109904, 57938):
242 /* 91fcc10cf15e012d27571e075b3b4dfe31754a8a padauk-3.0/Padauk-bookbold.ttf */
243 case HB_CODEPOINT_ENCODE3 (1330, 109904, 58972):
244 /* sha1sum: c26e41d567ed821bed997e937bc0c41435689e85 Padauk.ttf
245 * "Padauk Regular" "Version 2.5", see https://crbug.com/681813 */
246 case HB_CODEPOINT_ENCODE3 (1004, 59092, 14836):
247 return true;
248 }
249 return false;
250 }
251
252 static void
253 _hb_ot_layout_set_glyph_props (hb_font_t *font,
254 hb_buffer_t *buffer)
255 {
256 _hb_buffer_assert_gsubgpos_vars (buffer);
257
258 const OT::GDEF &gdef = *font->face->table.GDEF->table;
259 unsigned int count = buffer->len;
260 for (unsigned int i = 0; i < count; i++)
261 {
262 _hb_glyph_info_set_glyph_props (&buffer->info[i], gdef.get_glyph_props (buffer->info[i].codepoint));
263 _hb_glyph_info_clear_lig_props (&buffer->info[i]);
264 }
265 }
266
267 /* Public API */
268
269 /**
270 * hb_ot_layout_has_glyph_classes:
271 * @face: #hb_face_t to work upon
272 *
273 * Tests whether a face has any glyph classes defined in its GDEF table.
274 *
275 * Return value: `true` if data found, `false` otherwise
276 *
277 **/
278 hb_bool_t
279 hb_ot_layout_has_glyph_classes (hb_face_t *face)
280 {
281 return face->table.GDEF->table->has_glyph_classes ();
282 }
283
284 /**
285 * hb_ot_layout_get_glyph_class:
286 * @face: The #hb_face_t to work on
287 * @glyph: The #hb_codepoint_t code point to query
288 *
289 * Fetches the GDEF class of the requested glyph in the specified face.
290 *
291 * Return value: The #hb_ot_layout_glyph_class_t glyph class of the given code
292 * point in the GDEF table of the face.
293 *
294 * Since: 0.9.7
295 **/
296 hb_ot_layout_glyph_class_t
297 hb_ot_layout_get_glyph_class (hb_face_t *face,
298 hb_codepoint_t glyph)
299 {
300 return (hb_ot_layout_glyph_class_t) face->table.GDEF->table->get_glyph_class (glyph);
301 }
302
303 /**
304 * hb_ot_layout_get_glyphs_in_class:
305 * @face: The #hb_face_t to work on
306 * @klass: The #hb_ot_layout_glyph_class_t GDEF class to retrieve
307 * @glyphs: (out): The #hb_set_t set of all glyphs belonging to the requested
308 * class.
309 *
310 * Retrieves the set of all glyphs from the face that belong to the requested
311 * glyph class in the face's GDEF table.
312 *
313 * Since: 0.9.7
314 **/
315 void
316 hb_ot_layout_get_glyphs_in_class (hb_face_t *face,
317 hb_ot_layout_glyph_class_t klass,
318 hb_set_t *glyphs /* OUT */)
319 {
320 return face->table.GDEF->table->get_glyphs_in_class (klass, glyphs);
321 }
322
323 #ifndef HB_NO_LAYOUT_UNUSED
324 /**
325 * hb_ot_layout_get_attach_points:
326 * @face: The #hb_face_t to work on
327 * @glyph: The #hb_codepoint_t code point to query
328 * @start_offset: offset of the first attachment point to retrieve
329 * @point_count: (inout) (optional): Input = the maximum number of attachment points to return;
330 * Output = the actual number of attachment points returned (may be zero)
331 * @point_array: (out) (array length=point_count): The array of attachment points found for the query
332 *
333 * Fetches a list of all attachment points for the specified glyph in the GDEF
334 * table of the face. The list returned will begin at the offset provided.
335 *
336 * Useful if the client program wishes to cache the list.
337 *
338 * Return value: Total number of attachment points for @glyph.
339 *
340 **/
341 unsigned int
342 hb_ot_layout_get_attach_points (hb_face_t *face,
343 hb_codepoint_t glyph,
344 unsigned int start_offset,
345 unsigned int *point_count /* IN/OUT */,
346 unsigned int *point_array /* OUT */)
347 {
348 return face->table.GDEF->table->get_attach_points (glyph,
349 start_offset,
350 point_count,
351 point_array);
352 }
353 /**
354 * hb_ot_layout_get_ligature_carets:
355 * @font: The #hb_font_t to work on
356 * @direction: The #hb_direction_t text direction to use
357 * @glyph: The #hb_codepoint_t code point to query
358 * @start_offset: offset of the first caret position to retrieve
359 * @caret_count: (inout) (optional): Input = the maximum number of caret positions to return;
360 * Output = the actual number of caret positions returned (may be zero)
361 * @caret_array: (out) (array length=caret_count): The array of caret positions found for the query
362 *
363 * Fetches a list of the caret positions defined for a ligature glyph in the GDEF
364 * table of the font. The list returned will begin at the offset provided.
365 *
366 * Note that a ligature that is formed from n characters will have n-1
367 * caret positions. The first character is not represented in the array,
368 * since its caret position is the glyph position.
369 *
370 * The positions returned by this function are 'unshaped', and will have to
371 * be fixed up for kerning that may be applied to the ligature glyph.
372 *
373 * Return value: Total number of ligature caret positions for @glyph.
374 *
375 **/
376 unsigned int
377 hb_ot_layout_get_ligature_carets (hb_font_t *font,
378 hb_direction_t direction,
379 hb_codepoint_t glyph,
380 unsigned int start_offset,
381 unsigned int *caret_count /* IN/OUT */,
382 hb_position_t *caret_array /* OUT */)
383 {
384 return font->face->table.GDEF->table->get_lig_carets (font, direction, glyph, start_offset, caret_count, caret_array);
385 }
386 #endif
387
388
389 /*
390 * GSUB/GPOS
391 */
392
393 bool
394 GSUB::is_blocklisted (hb_blob_t *blob HB_UNUSED,
395 hb_face_t *face) const
396 {
397 #ifdef HB_NO_OT_LAYOUT_BLOCKLIST
398 return false;
399 #endif
400 return false;
401 }
402
403 bool
404 GPOS::is_blocklisted (hb_blob_t *blob HB_UNUSED,
405 hb_face_t *face HB_UNUSED) const
406 {
407 #ifdef HB_NO_OT_LAYOUT_BLOCKLIST
408 return false;
409 #endif
410 return false;
411 }
412
413 static const OT::GSUBGPOS&
414 get_gsubgpos_table (hb_face_t *face,
415 hb_tag_t table_tag)
416 {
417 switch (table_tag) {
418 case HB_OT_TAG_GSUB: return *face->table.GSUB->table;
419 case HB_OT_TAG_GPOS: return *face->table.GPOS->table;
420 default: return Null (OT::GSUBGPOS);
421 }
422 }
423
424
425 /**
426 * hb_ot_layout_table_get_script_tags:
427 * @face: #hb_face_t to work upon
428 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
429 * @start_offset: offset of the first script tag to retrieve
430 * @script_count: (inout) (optional): Input = the maximum number of script tags to return;
431 * Output = the actual number of script tags returned (may be zero)
432 * @script_tags: (out) (array length=script_count): The array of #hb_tag_t script tags found for the query
433 *
434 * Fetches a list of all scripts enumerated in the specified face's GSUB table
435 * or GPOS table. The list returned will begin at the offset provided.
436 *
437 * Return value: Total number of script tags.
438 *
439 **/
440 unsigned int
441 hb_ot_layout_table_get_script_tags (hb_face_t *face,
442 hb_tag_t table_tag,
443 unsigned int start_offset,
444 unsigned int *script_count /* IN/OUT */,
445 hb_tag_t *script_tags /* OUT */)
446 {
447 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
448
449 return g.get_script_tags (start_offset, script_count, script_tags);
450 }
451
452 #define HB_OT_TAG_LATIN_SCRIPT HB_TAG ('l', 'a', 't', 'n')
453
454 /**
455 * hb_ot_layout_table_find_script:
456 * @face: #hb_face_t to work upon
457 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
458 * @script_tag: #hb_tag_t of the script tag requested
459 * @script_index: (out): The index of the requested script tag
460 *
461 * Fetches the index if a given script tag in the specified face's GSUB table
462 * or GPOS table.
463 *
464 * Return value: `true` if the script is found, `false` otherwise
465 *
466 **/
467 hb_bool_t
468 hb_ot_layout_table_find_script (hb_face_t *face,
469 hb_tag_t table_tag,
470 hb_tag_t script_tag,
471 unsigned int *script_index /* OUT */)
472 {
473 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX), "");
474 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
475
476 if (g.find_script_index (script_tag, script_index))
477 return true;
478
479 /* try finding 'DFLT' */
480 if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index))
481 return false;
482
483 /* try with 'dflt'; MS site has had typos and many fonts use it now :(.
484 * including many versions of DejaVu Sans Mono! */
485 if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index))
486 return false;
487
488 /* try with 'latn'; some old fonts put their features there even though
489 they're really trying to support Thai, for example :( */
490 if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index))
491 return false;
492
493 if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
494 return false;
495 }
496
497 #ifndef HB_DISABLE_DEPRECATED
498 /**
499 * hb_ot_layout_table_choose_script:
500 * @face: #hb_face_t to work upon
501 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
502 * @script_tags: Array of #hb_tag_t script tags
503 * @script_index: (out): The index of the requested script tag
504 * @chosen_script: (out): #hb_tag_t of the script tag requested
505 *
506 * Deprecated since 2.0.0
507 **/
508 hb_bool_t
509 hb_ot_layout_table_choose_script (hb_face_t *face,
510 hb_tag_t table_tag,
511 const hb_tag_t *script_tags,
512 unsigned int *script_index /* OUT */,
513 hb_tag_t *chosen_script /* OUT */)
514 {
515 const hb_tag_t *t;
516 for (t = script_tags; *t; t++);
517 return hb_ot_layout_table_select_script (face, table_tag, t - script_tags, script_tags, script_index, chosen_script);
518 }
519 #endif
520
521 /**
522 * hb_ot_layout_table_select_script:
523 * @face: #hb_face_t to work upon
524 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
525 * @script_count: Number of script tags in the array
526 * @script_tags: Array of #hb_tag_t script tags
527 * @script_index: (out) (optional): The index of the requested script
528 * @chosen_script: (out) (optional): #hb_tag_t of the requested script
529 *
530 * Selects an OpenType script for @table_tag from the @script_tags array.
531 *
532 * If the table does not have any of the requested scripts, then `DFLT`,
533 * `dflt`, and `latn` tags are tried in that order. If the table still does not
534 * have any of these scripts, @script_index and @chosen_script are set to
535 * #HB_OT_LAYOUT_NO_SCRIPT_INDEX.
536 *
537 * Return value:
538 * `true` if one of the requested scripts is selected, `false` if a fallback
539 * script is selected or if no scripts are selected.
540 *
541 * Since: 2.0.0
542 **/
543 hb_bool_t
544 hb_ot_layout_table_select_script (hb_face_t *face,
545 hb_tag_t table_tag,
546 unsigned int script_count,
547 const hb_tag_t *script_tags,
548 unsigned int *script_index /* OUT */,
549 hb_tag_t *chosen_script /* OUT */)
550 {
551 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX), "");
552 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
553 unsigned int i;
554
555 for (i = 0; i < script_count; i++)
556 {
557 if (g.find_script_index (script_tags[i], script_index))
558 {
559 if (chosen_script)
560 *chosen_script = script_tags[i];
561 return true;
562 }
563 }
564
565 /* try finding 'DFLT' */
566 if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index)) {
567 if (chosen_script)
568 *chosen_script = HB_OT_TAG_DEFAULT_SCRIPT;
569 return false;
570 }
571
572 /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
573 if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index)) {
574 if (chosen_script)
575 *chosen_script = HB_OT_TAG_DEFAULT_LANGUAGE;
576 return false;
577 }
578
579 /* try with 'latn'; some old fonts put their features there even though
580 they're really trying to support Thai, for example :( */
581 if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index)) {
582 if (chosen_script)
583 *chosen_script = HB_OT_TAG_LATIN_SCRIPT;
584 return false;
585 }
586
587 if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
588 if (chosen_script)
589 *chosen_script = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
590 return false;
591 }
592
593
594 /**
595 * hb_ot_layout_table_get_feature_tags:
596 * @face: #hb_face_t to work upon
597 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
598 * @start_offset: offset of the first feature tag to retrieve
599 * @feature_count: (inout) (optional): Input = the maximum number of feature tags to return;
600 * Output = the actual number of feature tags returned (may be zero)
601 * @feature_tags: (out) (array length=feature_count): Array of feature tags found in the table
602 *
603 * Fetches a list of all feature tags in the given face's GSUB or GPOS table.
604 * Note that there might be duplicate feature tags, belonging to different
605 * script/language-system pairs of the table.
606 *
607 * Return value: Total number of feature tags.
608 *
609 * Since: 0.6.0
610 *
611 **/
612 unsigned int
613 hb_ot_layout_table_get_feature_tags (hb_face_t *face,
614 hb_tag_t table_tag,
615 unsigned int start_offset,
616 unsigned int *feature_count /* IN/OUT */,
617 hb_tag_t *feature_tags /* OUT */)
618 {
619 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
620
621 return g.get_feature_tags (start_offset, feature_count, feature_tags);
622 }
623
624
625 /**
626 * hb_ot_layout_table_find_feature:
627 * @face: #hb_face_t to work upon
628 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
629 * @feature_tag: The #hb_tag_t of the requested feature tag
630 * @feature_index: (out): The index of the requested feature
631 *
632 * Fetches the index for a given feature tag in the specified face's GSUB table
633 * or GPOS table.
634 *
635 * Return value: `true` if the feature is found, `false` otherwise
636 *
637 * Since: 0.6.0
638 *
639 **/
640 bool
641 hb_ot_layout_table_find_feature (hb_face_t *face,
642 hb_tag_t table_tag,
643 hb_tag_t feature_tag,
644 unsigned int *feature_index /* OUT */)
645 {
646 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX), "");
647 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
648
649 unsigned int num_features = g.get_feature_count ();
650 for (unsigned int i = 0; i < num_features; i++)
651 {
652 if (feature_tag == g.get_feature_tag (i)) {
653 if (feature_index) *feature_index = i;
654 return true;
655 }
656 }
657
658 if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
659 return false;
660 }
661
662
663 /**
664 * hb_ot_layout_script_get_language_tags:
665 * @face: #hb_face_t to work upon
666 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
667 * @script_index: The index of the requested script tag
668 * @start_offset: offset of the first language tag to retrieve
669 * @language_count: (inout) (optional): Input = the maximum number of language tags to return;
670 * Output = the actual number of language tags returned (may be zero)
671 * @language_tags: (out) (array length=language_count): Array of language tags found in the table
672 *
673 * Fetches a list of language tags in the given face's GSUB or GPOS table, underneath
674 * the specified script index. The list returned will begin at the offset provided.
675 *
676 * Return value: Total number of language tags.
677 *
678 * Since: 0.6.0
679 *
680 **/
681 unsigned int
682 hb_ot_layout_script_get_language_tags (hb_face_t *face,
683 hb_tag_t table_tag,
684 unsigned int script_index,
685 unsigned int start_offset,
686 unsigned int *language_count /* IN/OUT */,
687 hb_tag_t *language_tags /* OUT */)
688 {
689 const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
690
691 return s.get_lang_sys_tags (start_offset, language_count, language_tags);
692 }
693
694
695 #ifndef HB_DISABLE_DEPRECATED
696 /**
697 * hb_ot_layout_script_find_language:
698 * @face: #hb_face_t to work upon
699 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
700 * @script_index: The index of the requested script tag
701 * @language_tag: The #hb_tag_t of the requested language
702 * @language_index: The index of the requested language
703 *
704 * Fetches the index of a given language tag in the specified face's GSUB table
705 * or GPOS table, underneath the specified script tag.
706 *
707 * Return value: `true` if the language tag is found, `false` otherwise
708 *
709 * Since: 0.6.0
710 * Deprecated: 2.0.0
711 **/
712 hb_bool_t
713 hb_ot_layout_script_find_language (hb_face_t *face,
714 hb_tag_t table_tag,
715 unsigned int script_index,
716 hb_tag_t language_tag,
717 unsigned int *language_index)
718 {
719 return hb_ot_layout_script_select_language (face,
720 table_tag,
721 script_index,
722 1,
723 &language_tag,
724 language_index);
725 }
726 #endif
727
728
729 /**
730 * hb_ot_layout_script_select_language:
731 * @face: #hb_face_t to work upon
732 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
733 * @script_index: The index of the requested script tag
734 * @language_count: The number of languages in the specified script
735 * @language_tags: The array of language tags
736 * @language_index: (out): The index of the requested language
737 *
738 * Fetches the index of the first language tag fom @language_tags that is present
739 * in the specified face's GSUB or GPOS table, underneath the specified script
740 * index.
741 *
742 * If none of the given language tags is found, `false` is returned and
743 * @language_index is set to the default language index.
744 *
745 * Return value: `true` if one of the given language tags is found, `false` otherwise
746 *
747 * Since: 2.0.0
748 **/
749 hb_bool_t
750 hb_ot_layout_script_select_language (hb_face_t *face,
751 hb_tag_t table_tag,
752 unsigned int script_index,
753 unsigned int language_count,
754 const hb_tag_t *language_tags,
755 unsigned int *language_index /* OUT */)
756 {
757 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX), "");
758 const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
759 unsigned int i;
760
761 for (i = 0; i < language_count; i++)
762 {
763 if (s.find_lang_sys_index (language_tags[i], language_index))
764 return true;
765 }
766
767 /* try finding 'dflt' */
768 if (s.find_lang_sys_index (HB_OT_TAG_DEFAULT_LANGUAGE, language_index))
769 return false;
770
771 if (language_index)
772 *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
773 return false;
774 }
775
776
777 /**
778 * hb_ot_layout_language_get_required_feature_index:
779 * @face: #hb_face_t to work upon
780 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
781 * @script_index: The index of the requested script tag
782 * @language_index: The index of the requested language tag
783 * @feature_index: (out): The index of the requested feature
784 *
785 * Fetches the index of a requested feature in the given face's GSUB or GPOS table,
786 * underneath the specified script and language.
787 *
788 * Return value: `true` if the feature is found, `false` otherwise
789 *
790 * Since: 0.6.0
791 *
792 **/
793 hb_bool_t
794 hb_ot_layout_language_get_required_feature_index (hb_face_t *face,
795 hb_tag_t table_tag,
796 unsigned int script_index,
797 unsigned int language_index,
798 unsigned int *feature_index /* OUT */)
799 {
800 return hb_ot_layout_language_get_required_feature (face,
801 table_tag,
802 script_index,
803 language_index,
804 feature_index,
805 nullptr);
806 }
807
808
809 /**
810 * hb_ot_layout_language_get_required_feature:
811 * @face: #hb_face_t to work upon
812 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
813 * @script_index: The index of the requested script tag
814 * @language_index: The index of the requested language tag
815 * @feature_index: (out): The index of the requested feature
816 * @feature_tag: (out): The #hb_tag_t of the requested feature
817 *
818 * Fetches the tag of a requested feature index in the given face's GSUB or GPOS table,
819 * underneath the specified script and language.
820 *
821 * Return value: `true` if the feature is found, `false` otherwise
822 *
823 * Since: 0.9.30
824 **/
825 hb_bool_t
826 hb_ot_layout_language_get_required_feature (hb_face_t *face,
827 hb_tag_t table_tag,
828 unsigned int script_index,
829 unsigned int language_index,
830 unsigned int *feature_index /* OUT */,
831 hb_tag_t *feature_tag /* OUT */)
832 {
833 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
834 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
835
836 unsigned int index = l.get_required_feature_index ();
837 if (feature_index) *feature_index = index;
838 if (feature_tag) *feature_tag = g.get_feature_tag (index);
839
840 return l.has_required_feature ();
841 }
842
843
844 /**
845 * hb_ot_layout_language_get_feature_indexes:
846 * @face: #hb_face_t to work upon
847 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
848 * @script_index: The index of the requested script tag
849 * @language_index: The index of the requested language tag
850 * @start_offset: offset of the first feature tag to retrieve
851 * @feature_count: (inout) (optional): Input = the maximum number of feature tags to return;
852 * Output: the actual number of feature tags returned (may be zero)
853 * @feature_indexes: (out) (array length=feature_count): The array of feature indexes found for the query
854 *
855 * Fetches a list of all features in the specified face's GSUB table
856 * or GPOS table, underneath the specified script and language. The list
857 * returned will begin at the offset provided.
858 *
859 * Return value: Total number of features.
860 *
861 * Since: 0.6.0
862 *
863 **/
864 unsigned int
865 hb_ot_layout_language_get_feature_indexes (hb_face_t *face,
866 hb_tag_t table_tag,
867 unsigned int script_index,
868 unsigned int language_index,
869 unsigned int start_offset,
870 unsigned int *feature_count /* IN/OUT */,
871 unsigned int *feature_indexes /* OUT */)
872 {
873 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
874 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
875
876 return l.get_feature_indexes (start_offset, feature_count, feature_indexes);
877 }
878
879
880 /**
881 * hb_ot_layout_language_get_feature_tags:
882 * @face: #hb_face_t to work upon
883 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
884 * @script_index: The index of the requested script tag
885 * @language_index: The index of the requested language tag
886 * @start_offset: offset of the first feature tag to retrieve
887 * @feature_count: (inout) (optional): Input = the maximum number of feature tags to return;
888 * Output = the actual number of feature tags returned (may be zero)
889 * @feature_tags: (out) (array length=feature_count): The array of #hb_tag_t feature tags found for the query
890 *
891 * Fetches a list of all features in the specified face's GSUB table
892 * or GPOS table, underneath the specified script and language. The list
893 * returned will begin at the offset provided.
894 *
895 * Return value: Total number of feature tags.
896 *
897 * Since: 0.6.0
898 *
899 **/
900 unsigned int
901 hb_ot_layout_language_get_feature_tags (hb_face_t *face,
902 hb_tag_t table_tag,
903 unsigned int script_index,
904 unsigned int language_index,
905 unsigned int start_offset,
906 unsigned int *feature_count /* IN/OUT */,
907 hb_tag_t *feature_tags /* OUT */)
908 {
909 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
910 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
911
912 static_assert ((sizeof (unsigned int) == sizeof (hb_tag_t)), "");
913 unsigned int ret = l.get_feature_indexes (start_offset, feature_count, (unsigned int *) feature_tags);
914
915 if (feature_tags) {
916 unsigned int count = *feature_count;
917 for (unsigned int i = 0; i < count; i++)
918 feature_tags[i] = g.get_feature_tag ((unsigned int) feature_tags[i]);
919 }
920
921 return ret;
922 }
923
924
925 /**
926 * hb_ot_layout_language_find_feature:
927 * @face: #hb_face_t to work upon
928 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
929 * @script_index: The index of the requested script tag
930 * @language_index: The index of the requested language tag
931 * @feature_tag: #hb_tag_t of the feature tag requested
932 * @feature_index: (out): The index of the requested feature
933 *
934 * Fetches the index of a given feature tag in the specified face's GSUB table
935 * or GPOS table, underneath the specified script and language.
936 *
937 * Return value: `true` if the feature is found, `false` otherwise
938 *
939 * Since: 0.6.0
940 *
941 **/
942 hb_bool_t
943 hb_ot_layout_language_find_feature (hb_face_t *face,
944 hb_tag_t table_tag,
945 unsigned int script_index,
946 unsigned int language_index,
947 hb_tag_t feature_tag,
948 unsigned int *feature_index /* OUT */)
949 {
950 static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX), "");
951 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
952 const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
953
954 unsigned int num_features = l.get_feature_count ();
955 for (unsigned int i = 0; i < num_features; i++) {
956 unsigned int f_index = l.get_feature_index (i);
957
958 if (feature_tag == g.get_feature_tag (f_index)) {
959 if (feature_index) *feature_index = f_index;
960 return true;
961 }
962 }
963
964 if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
965 return false;
966 }
967
968
969 /**
970 * hb_ot_layout_feature_get_lookups:
971 * @face: #hb_face_t to work upon
972 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
973 * @feature_index: The index of the requested feature
974 * @start_offset: offset of the first lookup to retrieve
975 * @lookup_count: (inout) (optional): Input = the maximum number of lookups to return;
976 * Output = the actual number of lookups returned (may be zero)
977 * @lookup_indexes: (out) (array length=lookup_count): The array of lookup indexes found for the query
978 *
979 * Fetches a list of all lookups enumerated for the specified feature, in
980 * the specified face's GSUB table or GPOS table. The list returned will
981 * begin at the offset provided.
982 *
983 * Return value: Total number of lookups.
984 *
985 * Since: 0.9.7
986 **/
987 unsigned int
988 hb_ot_layout_feature_get_lookups (hb_face_t *face,
989 hb_tag_t table_tag,
990 unsigned int feature_index,
991 unsigned int start_offset,
992 unsigned int *lookup_count /* IN/OUT */,
993 unsigned int *lookup_indexes /* OUT */)
994 {
995 return hb_ot_layout_feature_with_variations_get_lookups (face,
996 table_tag,
997 feature_index,
998 HB_OT_LAYOUT_NO_VARIATIONS_INDEX,
999 start_offset,
1000 lookup_count,
1001 lookup_indexes);
1002 }
1003
1004
1005 /**
1006 * hb_ot_layout_table_get_lookup_count:
1007 * @face: #hb_face_t to work upon
1008 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1009 *
1010 * Fetches the total number of lookups enumerated in the specified
1011 * face's GSUB table or GPOS table.
1012 *
1013 * Return value: Total number of lookups.
1014 *
1015 * Since: 0.9.22
1016 **/
1017 unsigned int
1018 hb_ot_layout_table_get_lookup_count (hb_face_t *face,
1019 hb_tag_t table_tag)
1020 {
1021 return get_gsubgpos_table (face, table_tag).get_lookup_count ();
1022 }
1023
1024
1025 struct hb_collect_features_context_t
1026 {
1027 hb_collect_features_context_t (hb_face_t *face,
1028 hb_tag_t table_tag,
1029 hb_set_t *feature_indices_,
1030 const hb_tag_t *features)
1031
1032 : g (get_gsubgpos_table (face, table_tag)),
1033 feature_indices (feature_indices_),
1034 has_feature_filter (false),
1035 script_count (0),langsys_count (0), feature_index_count (0)
1036 {
1037 compute_feature_filter (features);
1038 }
1039
1040 void compute_feature_filter (const hb_tag_t *features)
1041 {
1042 if (features == nullptr)
1043 {
1044 has_feature_filter = false;
1045 return;
1046 }
1047
1048 has_feature_filter = true;
1049 hb_set_t features_set;
1050 for (; *features; features++)
1051 features_set.add (*features);
1052
1053 for (unsigned i = 0; i < g.get_feature_count (); i++)
1054 {
1055 hb_tag_t tag = g.get_feature_tag (i);
1056 if (features_set.has (tag))
1057 feature_indices_filter.add(i);
1058 }
1059 }
1060
1061 bool visited (const OT::Script &s)
1062 {
1063 /* We might have Null() object here. Don't want to involve
1064 * that in the memoize. So, detect empty objects and return. */
1065 if (unlikely (!s.has_default_lang_sys () &&
1066 !s.get_lang_sys_count ()))
1067 return true;
1068
1069 if (script_count++ > HB_MAX_SCRIPTS)
1070 return true;
1071
1072 return visited (s, visited_script);
1073 }
1074 bool visited (const OT::LangSys &l)
1075 {
1076 /* We might have Null() object here. Don't want to involve
1077 * that in the memoize. So, detect empty objects and return. */
1078 if (unlikely (!l.has_required_feature () &&
1079 !l.get_feature_count ()))
1080 return true;
1081
1082 if (langsys_count++ > HB_MAX_LANGSYS)
1083 return true;
1084
1085 return visited (l, visited_langsys);
1086 }
1087
1088 bool visited_feature_indices (unsigned count)
1089 {
1090 feature_index_count += count;
1091 return feature_index_count > HB_MAX_FEATURE_INDICES;
1092 }
1093
1094 private:
1095 template <typename T>
1096 bool visited (const T &p, hb_set_t &visited_set)
1097 {
1098 hb_codepoint_t delta = (hb_codepoint_t) ((uintptr_t) &p - (uintptr_t) &g);
1099 if (visited_set.has (delta))
1100 return true;
1101
1102 visited_set.add (delta);
1103 return false;
1104 }
1105
1106 public:
1107 const OT::GSUBGPOS &g;
1108 hb_set_t *feature_indices;
1109 hb_set_t feature_indices_filter;
1110 bool has_feature_filter;
1111
1112 private:
1113 hb_set_t visited_script;
1114 hb_set_t visited_langsys;
1115 unsigned int script_count;
1116 unsigned int langsys_count;
1117 unsigned int feature_index_count;
1118 };
1119
1120 static void
1121 langsys_collect_features (hb_collect_features_context_t *c,
1122 const OT::LangSys &l)
1123 {
1124 if (c->visited (l)) return;
1125
1126 if (!c->has_feature_filter)
1127 {
1128 /* All features. */
1129 if (l.has_required_feature () && !c->visited_feature_indices (1))
1130 c->feature_indices->add (l.get_required_feature_index ());
1131
1132 // TODO(garretrieger): filter out indices >= feature count?
1133 if (!c->visited_feature_indices (l.featureIndex.len))
1134 l.add_feature_indexes_to (c->feature_indices);
1135 }
1136 else
1137 {
1138 if (c->feature_indices_filter.is_empty()) return;
1139 unsigned int num_features = l.get_feature_count ();
1140 for (unsigned int i = 0; i < num_features; i++)
1141 {
1142 unsigned int feature_index = l.get_feature_index (i);
1143 if (!c->feature_indices_filter.has (feature_index)) continue;
1144
1145 c->feature_indices->add (feature_index);
1146 c->feature_indices_filter.del (feature_index);
1147 }
1148 }
1149 }
1150
1151 static void
1152 script_collect_features (hb_collect_features_context_t *c,
1153 const OT::Script &s,
1154 const hb_tag_t *languages)
1155 {
1156 if (c->visited (s)) return;
1157
1158 if (!languages)
1159 {
1160 /* All languages. */
1161 if (s.has_default_lang_sys ())
1162 langsys_collect_features (c,
1163 s.get_default_lang_sys ());
1164
1165
1166 unsigned int count = s.get_lang_sys_count ();
1167 for (unsigned int language_index = 0; language_index < count; language_index++)
1168 langsys_collect_features (c,
1169 s.get_lang_sys (language_index));
1170 }
1171 else
1172 {
1173 for (; *languages; languages++)
1174 {
1175 unsigned int language_index;
1176 if (s.find_lang_sys_index (*languages, &language_index))
1177 langsys_collect_features (c,
1178 s.get_lang_sys (language_index));
1179
1180 }
1181 }
1182 }
1183
1184
1185 /**
1186 * hb_ot_layout_collect_features:
1187 * @face: #hb_face_t to work upon
1188 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1189 * @scripts: (nullable) (array zero-terminated=1): The array of scripts to collect features for,
1190 * terminated by %HB_TAG_NONE
1191 * @languages: (nullable) (array zero-terminated=1): The array of languages to collect features for,
1192 * terminated by %HB_TAG_NONE
1193 * @features: (nullable) (array zero-terminated=1): The array of features to collect,
1194 * terminated by %HB_TAG_NONE
1195 * @feature_indexes: (out): The array of feature indexes found for the query
1196 *
1197 * Fetches a list of all feature indexes in the specified face's GSUB table
1198 * or GPOS table, underneath the specified scripts, languages, and features.
1199 * If no list of scripts is provided, all scripts will be queried. If no list
1200 * of languages is provided, all languages will be queried. If no list of
1201 * features is provided, all features will be queried.
1202 *
1203 * Since: 1.8.5
1204 **/
1205 void
1206 hb_ot_layout_collect_features (hb_face_t *face,
1207 hb_tag_t table_tag,
1208 const hb_tag_t *scripts,
1209 const hb_tag_t *languages,
1210 const hb_tag_t *features,
1211 hb_set_t *feature_indexes /* OUT */)
1212 {
1213 hb_collect_features_context_t c (face, table_tag, feature_indexes, features);
1214 if (!scripts)
1215 {
1216 /* All scripts. */
1217 unsigned int count = c.g.get_script_count ();
1218 for (unsigned int script_index = 0; script_index < count; script_index++)
1219 script_collect_features (&c,
1220 c.g.get_script (script_index),
1221 languages);
1222 }
1223 else
1224 {
1225 for (; *scripts; scripts++)
1226 {
1227 unsigned int script_index;
1228 if (c.g.find_script_index (*scripts, &script_index))
1229 script_collect_features (&c,
1230 c.g.get_script (script_index),
1231 languages);
1232 }
1233 }
1234 }
1235
1236
1237 /**
1238 * hb_ot_layout_collect_lookups:
1239 * @face: #hb_face_t to work upon
1240 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1241 * @scripts: (nullable) (array zero-terminated=1): The array of scripts to collect lookups for,
1242 * terminated by %HB_TAG_NONE
1243 * @languages: (nullable) (array zero-terminated=1): The array of languages to collect lookups for,
1244 * terminated by %HB_TAG_NONE
1245 * @features: (nullable) (array zero-terminated=1): The array of features to collect lookups for,
1246 * terminated by %HB_TAG_NONE
1247 * @lookup_indexes: (out): The array of lookup indexes found for the query
1248 *
1249 * Fetches a list of all feature-lookup indexes in the specified face's GSUB
1250 * table or GPOS table, underneath the specified scripts, languages, and
1251 * features. If no list of scripts is provided, all scripts will be queried.
1252 * If no list of languages is provided, all languages will be queried. If no
1253 * list of features is provided, all features will be queried.
1254 *
1255 * Since: 0.9.8
1256 **/
1257 void
1258 hb_ot_layout_collect_lookups (hb_face_t *face,
1259 hb_tag_t table_tag,
1260 const hb_tag_t *scripts,
1261 const hb_tag_t *languages,
1262 const hb_tag_t *features,
1263 hb_set_t *lookup_indexes /* OUT */)
1264 {
1265 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1266
1267 hb_set_t feature_indexes;
1268 hb_ot_layout_collect_features (face, table_tag, scripts, languages, features, &feature_indexes);
1269
1270 for (hb_codepoint_t feature_index = HB_SET_VALUE_INVALID;
1271 hb_set_next (&feature_indexes, &feature_index);)
1272 g.get_feature (feature_index).add_lookup_indexes_to (lookup_indexes);
1273
1274 g.feature_variation_collect_lookups (&feature_indexes, nullptr, lookup_indexes);
1275 }
1276
1277
1278 #ifndef HB_NO_LAYOUT_COLLECT_GLYPHS
1279 /**
1280 * hb_ot_layout_lookup_collect_glyphs:
1281 * @face: #hb_face_t to work upon
1282 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1283 * @lookup_index: The index of the feature lookup to query
1284 * @glyphs_before: (out): Array of glyphs preceding the substitution range
1285 * @glyphs_input: (out): Array of input glyphs that would be substituted by the lookup
1286 * @glyphs_after: (out): Array of glyphs following the substitution range
1287 * @glyphs_output: (out): Array of glyphs that would be the substituted output of the lookup
1288 *
1289 * Fetches a list of all glyphs affected by the specified lookup in the
1290 * specified face's GSUB table or GPOS table.
1291 *
1292 * Since: 0.9.7
1293 **/
1294 void
1295 hb_ot_layout_lookup_collect_glyphs (hb_face_t *face,
1296 hb_tag_t table_tag,
1297 unsigned int lookup_index,
1298 hb_set_t *glyphs_before, /* OUT. May be NULL */
1299 hb_set_t *glyphs_input, /* OUT. May be NULL */
1300 hb_set_t *glyphs_after, /* OUT. May be NULL */
1301 hb_set_t *glyphs_output /* OUT. May be NULL */)
1302 {
1303 OT::hb_collect_glyphs_context_t c (face,
1304 glyphs_before,
1305 glyphs_input,
1306 glyphs_after,
1307 glyphs_output);
1308
1309 switch (table_tag)
1310 {
1311 case HB_OT_TAG_GSUB:
1312 {
1313 const OT::SubstLookup& l = face->table.GSUB->table->get_lookup (lookup_index);
1314 l.collect_glyphs (&c);
1315 return;
1316 }
1317 case HB_OT_TAG_GPOS:
1318 {
1319 const OT::PosLookup& l = face->table.GPOS->table->get_lookup (lookup_index);
1320 l.collect_glyphs (&c);
1321 return;
1322 }
1323 }
1324 }
1325 #endif
1326
1327
1328 /* Variations support */
1329
1330
1331 /**
1332 * hb_ot_layout_table_find_feature_variations:
1333 * @face: #hb_face_t to work upon
1334 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1335 * @coords: The variation coordinates to query
1336 * @num_coords: The number of variation coordinates
1337 * @variations_index: (out): The array of feature variations found for the query
1338 *
1339 * Fetches a list of feature variations in the specified face's GSUB table
1340 * or GPOS table, at the specified variation coordinates.
1341 *
1342 * Return value: `true` if feature variations were found, `false` otherwise.
1343 *
1344 * Since: 1.4.0
1345 *
1346 **/
1347 hb_bool_t
1348 hb_ot_layout_table_find_feature_variations (hb_face_t *face,
1349 hb_tag_t table_tag,
1350 const int *coords,
1351 unsigned int num_coords,
1352 unsigned int *variations_index /* out */)
1353 {
1354 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1355
1356 return g.find_variations_index (coords, num_coords, variations_index);
1357 }
1358
1359
1360 /**
1361 * hb_ot_layout_feature_with_variations_get_lookups:
1362 * @face: #hb_face_t to work upon
1363 * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
1364 * @feature_index: The index of the feature to query
1365 * @variations_index: The index of the feature variation to query
1366 * @start_offset: offset of the first lookup to retrieve
1367 * @lookup_count: (inout) (optional): Input = the maximum number of lookups to return;
1368 * Output = the actual number of lookups returned (may be zero)
1369 * @lookup_indexes: (out) (array length=lookup_count): The array of lookups found for the query
1370 *
1371 * Fetches a list of all lookups enumerated for the specified feature, in
1372 * the specified face's GSUB table or GPOS table, enabled at the specified
1373 * variations index. The list returned will begin at the offset provided.
1374 *
1375 * Return value: Total number of lookups.
1376 *
1377 * Since: 1.4.0
1378 *
1379 **/
1380 unsigned int
1381 hb_ot_layout_feature_with_variations_get_lookups (hb_face_t *face,
1382 hb_tag_t table_tag,
1383 unsigned int feature_index,
1384 unsigned int variations_index,
1385 unsigned int start_offset,
1386 unsigned int *lookup_count /* IN/OUT */,
1387 unsigned int *lookup_indexes /* OUT */)
1388 {
1389 static_assert ((OT::FeatureVariations::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_VARIATIONS_INDEX), "");
1390 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1391
1392 const OT::Feature &f = g.get_feature_variation (feature_index, variations_index);
1393
1394 return f.get_lookup_indexes (start_offset, lookup_count, lookup_indexes);
1395 }
1396
1397
1398 /*
1399 * OT::GSUB
1400 */
1401
1402
1403 /**
1404 * hb_ot_layout_has_substitution:
1405 * @face: #hb_face_t to work upon
1406 *
1407 * Tests whether the specified face includes any GSUB substitutions.
1408 *
1409 * Return value: `true` if data found, `false` otherwise
1410 *
1411 * Since: 0.6.0
1412 *
1413 **/
1414 hb_bool_t
1415 hb_ot_layout_has_substitution (hb_face_t *face)
1416 {
1417 return face->table.GSUB->table->has_data ();
1418 }
1419
1420
1421 /**
1422 * hb_ot_layout_lookup_would_substitute:
1423 * @face: #hb_face_t to work upon
1424 * @lookup_index: The index of the lookup to query
1425 * @glyphs: The sequence of glyphs to query for substitution
1426 * @glyphs_length: The length of the glyph sequence
1427 * @zero_context: #hb_bool_t indicating whether pre-/post-context are disallowed
1428 * in substitutions
1429 *
1430 * Tests whether a specified lookup in the specified face would
1431 * trigger a substitution on the given glyph sequence.
1432 *
1433 * Return value: `true` if a substitution would be triggered, `false` otherwise
1434 *
1435 * Since: 0.9.7
1436 **/
1437 hb_bool_t
1438 hb_ot_layout_lookup_would_substitute (hb_face_t *face,
1439 unsigned int lookup_index,
1440 const hb_codepoint_t *glyphs,
1441 unsigned int glyphs_length,
1442 hb_bool_t zero_context)
1443 {
1444 if (unlikely (lookup_index >= face->table.GSUB->lookup_count)) return false;
1445 OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, (bool) zero_context);
1446
1447 const OT::SubstLookup& l = face->table.GSUB->table->get_lookup (lookup_index);
1448 return l.would_apply (&c, &face->table.GSUB->accels[lookup_index]);
1449 }
1450
1451
1452 /**
1453 * hb_ot_layout_substitute_start:
1454 * @font: #hb_font_t to use
1455 * @buffer: #hb_buffer_t buffer to work upon
1456 *
1457 * Called before substitution lookups are performed, to ensure that glyph
1458 * class and other properties are set on the glyphs in the buffer.
1459 *
1460 **/
1461 void
1462 hb_ot_layout_substitute_start (hb_font_t *font,
1463 hb_buffer_t *buffer)
1464 {
1465 _hb_ot_layout_set_glyph_props (font, buffer);
1466 }
1467
1468 /**
1469 * hb_ot_layout_lookup_substitute_closure:
1470 * @face: #hb_face_t to work upon
1471 * @lookup_index: index of the feature lookup to query
1472 * @glyphs: (out): Array of glyphs comprising the transitive closure of the lookup
1473 *
1474 * Compute the transitive closure of glyphs needed for a
1475 * specified lookup.
1476 *
1477 * Since: 0.9.7
1478 **/
1479 void
1480 hb_ot_layout_lookup_substitute_closure (hb_face_t *face,
1481 unsigned int lookup_index,
1482 hb_set_t *glyphs /* OUT */)
1483 {
1484 hb_map_t done_lookups_glyph_count;
1485 hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> done_lookups_glyph_set;
1486 OT::hb_closure_context_t c (face, glyphs, &done_lookups_glyph_count, &done_lookups_glyph_set);
1487
1488 const OT::SubstLookup& l = face->table.GSUB->table->get_lookup (lookup_index);
1489
1490 l.closure (&c, lookup_index);
1491 }
1492
1493 /**
1494 * hb_ot_layout_lookups_substitute_closure:
1495 * @face: #hb_face_t to work upon
1496 * @lookups: The set of lookups to query
1497 * @glyphs: (out): Array of glyphs comprising the transitive closure of the lookups
1498 *
1499 * Compute the transitive closure of glyphs needed for all of the
1500 * provided lookups.
1501 *
1502 * Since: 1.8.1
1503 **/
1504 void
1505 hb_ot_layout_lookups_substitute_closure (hb_face_t *face,
1506 const hb_set_t *lookups,
1507 hb_set_t *glyphs /* OUT */)
1508 {
1509 hb_map_t done_lookups_glyph_count;
1510 hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> done_lookups_glyph_set;
1511 OT::hb_closure_context_t c (face, glyphs, &done_lookups_glyph_count, &done_lookups_glyph_set);
1512 const GSUB& gsub = *face->table.GSUB->table;
1513
1514 unsigned int iteration_count = 0;
1515 unsigned int glyphs_length;
1516 do
1517 {
1518 c.reset_lookup_visit_count ();
1519 glyphs_length = glyphs->get_population ();
1520 if (lookups)
1521 {
1522 for (hb_codepoint_t lookup_index = HB_SET_VALUE_INVALID; hb_set_next (lookups, &lookup_index);)
1523 gsub.get_lookup (lookup_index).closure (&c, lookup_index);
1524 }
1525 else
1526 {
1527 for (unsigned int i = 0; i < gsub.get_lookup_count (); i++)
1528 gsub.get_lookup (i).closure (&c, i);
1529 }
1530 } while (iteration_count++ <= HB_CLOSURE_MAX_STAGES &&
1531 glyphs_length != glyphs->get_population ());
1532 }
1533
1534 /*
1535 * GPOS
1536 */
1537
1538
1539 /**
1540 * hb_ot_layout_has_positioning:
1541 * @face: #hb_face_t to work upon
1542 *
1543 * Tests whether the specified face includes any GPOS positioning.
1544 *
1545 * Return value: `true` if the face has GPOS data, `false` otherwise
1546 *
1547 **/
1548 hb_bool_t
1549 hb_ot_layout_has_positioning (hb_face_t *face)
1550 {
1551 return face->table.GPOS->table->has_data ();
1552 }
1553
1554 /**
1555 * hb_ot_layout_position_start:
1556 * @font: #hb_font_t to use
1557 * @buffer: #hb_buffer_t buffer to work upon
1558 *
1559 * Called before positioning lookups are performed, to ensure that glyph
1560 * attachment types and glyph-attachment chains are set for the glyphs in the buffer.
1561 *
1562 **/
1563 void
1564 hb_ot_layout_position_start (hb_font_t *font, hb_buffer_t *buffer)
1565 {
1566 GPOS::position_start (font, buffer);
1567 }
1568
1569
1570 /**
1571 * hb_ot_layout_position_finish_advances:
1572 * @font: #hb_font_t to use
1573 * @buffer: #hb_buffer_t buffer to work upon
1574 *
1575 * Called after positioning lookups are performed, to finish glyph advances.
1576 *
1577 **/
1578 void
1579 hb_ot_layout_position_finish_advances (hb_font_t *font, hb_buffer_t *buffer)
1580 {
1581 GPOS::position_finish_advances (font, buffer);
1582 }
1583
1584 /**
1585 * hb_ot_layout_position_finish_offsets:
1586 * @font: #hb_font_t to use
1587 * @buffer: #hb_buffer_t buffer to work upon
1588 *
1589 * Called after positioning lookups are performed, to finish glyph offsets.
1590 *
1591 **/
1592 void
1593 hb_ot_layout_position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer)
1594 {
1595 GPOS::position_finish_offsets (font, buffer);
1596 }
1597
1598
1599 #ifndef HB_NO_LAYOUT_FEATURE_PARAMS
1600 /**
1601 * hb_ot_layout_get_size_params:
1602 * @face: #hb_face_t to work upon
1603 * @design_size: (out): The design size of the face
1604 * @subfamily_id: (out): The identifier of the face within the font subfamily
1605 * @subfamily_name_id: (out): The ‘name’ table name ID of the face within the font subfamily
1606 * @range_start: (out): The minimum size of the recommended size range for the face
1607 * @range_end: (out): The maximum size of the recommended size range for the face
1608 *
1609 * Fetches optical-size feature data (i.e., the `size` feature from GPOS). Note that
1610 * the subfamily_id and the subfamily name string (accessible via the subfamily_name_id)
1611 * as used here are defined as pertaining only to fonts within a font family that differ
1612 * specifically in their respective size ranges; other ways to differentiate fonts within
1613 * a subfamily are not covered by the `size` feature.
1614 *
1615 * For more information on this distinction, see the [`size` feature documentation](
1616 * https://docs.microsoft.com/en-us/typography/opentype/spec/features_pt#tag-size).
1617 *
1618 * Return value: `true` if data found, `false` otherwise
1619 *
1620 * Since: 0.9.10
1621 **/
1622 hb_bool_t
1623 hb_ot_layout_get_size_params (hb_face_t *face,
1624 unsigned int *design_size, /* OUT. May be NULL */
1625 unsigned int *subfamily_id, /* OUT. May be NULL */
1626 hb_ot_name_id_t *subfamily_name_id, /* OUT. May be NULL */
1627 unsigned int *range_start, /* OUT. May be NULL */
1628 unsigned int *range_end /* OUT. May be NULL */)
1629 {
1630 const GPOS &gpos = *face->table.GPOS->table;
1631 const hb_tag_t tag = HB_TAG ('s','i','z','e');
1632
1633 unsigned int num_features = gpos.get_feature_count ();
1634 for (unsigned int i = 0; i < num_features; i++)
1635 {
1636 if (tag == gpos.get_feature_tag (i))
1637 {
1638 const OT::Feature &f = gpos.get_feature (i);
1639 const OT::FeatureParamsSize &params = f.get_feature_params ().get_size_params (tag);
1640
1641 if (params.designSize)
1642 {
1643 if (design_size) *design_size = params.designSize;
1644 if (subfamily_id) *subfamily_id = params.subfamilyID;
1645 if (subfamily_name_id) *subfamily_name_id = params.subfamilyNameID;
1646 if (range_start) *range_start = params.rangeStart;
1647 if (range_end) *range_end = params.rangeEnd;
1648
1649 return true;
1650 }
1651 }
1652 }
1653
1654 if (design_size) *design_size = 0;
1655 if (subfamily_id) *subfamily_id = 0;
1656 if (subfamily_name_id) *subfamily_name_id = HB_OT_NAME_ID_INVALID;
1657 if (range_start) *range_start = 0;
1658 if (range_end) *range_end = 0;
1659
1660 return false;
1661 }
1662
1663
1664 /**
1665 * hb_ot_layout_feature_get_name_ids:
1666 * @face: #hb_face_t to work upon
1667 * @table_tag: table tag to query, "GSUB" or "GPOS".
1668 * @feature_index: index of feature to query.
1669 * @label_id: (out) (optional): The ‘name’ table name ID that specifies a string
1670 * for a user-interface label for this feature. (May be NULL.)
1671 * @tooltip_id: (out) (optional): The ‘name’ table name ID that specifies a string
1672 * that an application can use for tooltip text for this
1673 * feature. (May be NULL.)
1674 * @sample_id: (out) (optional): The ‘name’ table name ID that specifies sample text
1675 * that illustrates the effect of this feature. (May be NULL.)
1676 * @num_named_parameters: (out) (optional): Number of named parameters. (May be zero.)
1677 * @first_param_id: (out) (optional): The first ‘name’ table name ID used to specify
1678 * strings for user-interface labels for the feature
1679 * parameters. (Must be zero if numParameters is zero.)
1680 *
1681 * Fetches name indices from feature parameters for "Stylistic Set" ('ssXX') or
1682 * "Character Variant" ('cvXX') features.
1683 *
1684 * Return value: `true` if data found, `false` otherwise
1685 *
1686 * Since: 2.0.0
1687 **/
1688 hb_bool_t
1689 hb_ot_layout_feature_get_name_ids (hb_face_t *face,
1690 hb_tag_t table_tag,
1691 unsigned int feature_index,
1692 hb_ot_name_id_t *label_id, /* OUT. May be NULL */
1693 hb_ot_name_id_t *tooltip_id, /* OUT. May be NULL */
1694 hb_ot_name_id_t *sample_id, /* OUT. May be NULL */
1695 unsigned int *num_named_parameters, /* OUT. May be NULL */
1696 hb_ot_name_id_t *first_param_id /* OUT. May be NULL */)
1697 {
1698 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1699
1700 hb_tag_t feature_tag = g.get_feature_tag (feature_index);
1701 const OT::Feature &f = g.get_feature (feature_index);
1702
1703 const OT::FeatureParams &feature_params = f.get_feature_params ();
1704 if (&feature_params != &Null (OT::FeatureParams))
1705 {
1706 const OT::FeatureParamsStylisticSet& ss_params =
1707 feature_params.get_stylistic_set_params (feature_tag);
1708 if (&ss_params != &Null (OT::FeatureParamsStylisticSet)) /* ssXX */
1709 {
1710 if (label_id) *label_id = ss_params.uiNameID;
1711 // ssXX features don't have the rest
1712 if (tooltip_id) *tooltip_id = HB_OT_NAME_ID_INVALID;
1713 if (sample_id) *sample_id = HB_OT_NAME_ID_INVALID;
1714 if (num_named_parameters) *num_named_parameters = 0;
1715 if (first_param_id) *first_param_id = HB_OT_NAME_ID_INVALID;
1716 return true;
1717 }
1718 const OT::FeatureParamsCharacterVariants& cv_params =
1719 feature_params.get_character_variants_params (feature_tag);
1720 if (&cv_params != &Null (OT::FeatureParamsCharacterVariants)) /* cvXX */
1721 {
1722 if (label_id) *label_id = cv_params.featUILableNameID;
1723 if (tooltip_id) *tooltip_id = cv_params.featUITooltipTextNameID;
1724 if (sample_id) *sample_id = cv_params.sampleTextNameID;
1725 if (num_named_parameters) *num_named_parameters = cv_params.numNamedParameters;
1726 if (first_param_id) *first_param_id = cv_params.firstParamUILabelNameID;
1727 return true;
1728 }
1729 }
1730
1731 if (label_id) *label_id = HB_OT_NAME_ID_INVALID;
1732 if (tooltip_id) *tooltip_id = HB_OT_NAME_ID_INVALID;
1733 if (sample_id) *sample_id = HB_OT_NAME_ID_INVALID;
1734 if (num_named_parameters) *num_named_parameters = 0;
1735 if (first_param_id) *first_param_id = HB_OT_NAME_ID_INVALID;
1736 return false;
1737 }
1738 /**
1739 * hb_ot_layout_feature_get_characters:
1740 * @face: #hb_face_t to work upon
1741 * @table_tag: table tag to query, "GSUB" or "GPOS".
1742 * @feature_index: index of feature to query.
1743 * @start_offset: offset of the first character to retrieve
1744 * @char_count: (inout) (optional): Input = the maximum number of characters to return;
1745 * Output = the actual number of characters returned (may be zero)
1746 * @characters: (out caller-allocates) (array length=char_count): A buffer pointer.
1747 * The Unicode codepoints of the characters for which this feature provides
1748 * glyph variants.
1749 *
1750 * Fetches a list of the characters defined as having a variant under the specified
1751 * "Character Variant" ("cvXX") feature tag.
1752 *
1753 * Return value: Number of total sample characters in the cvXX feature.
1754 *
1755 * Since: 2.0.0
1756 **/
1757 unsigned int
1758 hb_ot_layout_feature_get_characters (hb_face_t *face,
1759 hb_tag_t table_tag,
1760 unsigned int feature_index,
1761 unsigned int start_offset,
1762 unsigned int *char_count, /* IN/OUT. May be NULL */
1763 hb_codepoint_t *characters /* OUT. May be NULL */)
1764 {
1765 const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
1766 return g.get_feature (feature_index)
1767 .get_feature_params ()
1768 .get_character_variants_params(g.get_feature_tag (feature_index))
1769 .get_characters (start_offset, char_count, characters);
1770 }
1771 #endif
1772
1773
1774 /*
1775 * Parts of different types are implemented here such that they have direct
1776 * access to GSUB/GPOS lookups.
1777 */
1778
1779
1780 struct GSUBProxy
1781 {
1782 static constexpr unsigned table_index = 0u;
1783 static constexpr bool always_inplace = false;
1784 typedef OT::SubstLookup Lookup;
1785
1786 GSUBProxy (hb_face_t *face) :
1787 table (*face->table.GSUB->table),
1788 accels (face->table.GSUB->accels) {}
1789
1790 const GSUB &table;
1791 const OT::hb_ot_layout_lookup_accelerator_t *accels;
1792 };
1793
1794 struct GPOSProxy
1795 {
1796 static constexpr unsigned table_index = 1u;
1797 static constexpr bool always_inplace = true;
1798 typedef OT::PosLookup Lookup;
1799
1800 GPOSProxy (hb_face_t *face) :
1801 table (*face->table.GPOS->table),
1802 accels (face->table.GPOS->accels) {}
1803
1804 const GPOS &table;
1805 const OT::hb_ot_layout_lookup_accelerator_t *accels;
1806 };
1807
1808
1809 static inline bool
1810 apply_forward (OT::hb_ot_apply_context_t *c,
1811 const OT::hb_ot_layout_lookup_accelerator_t &accel)
1812 {
1813 bool use_cache = accel.cache_enter (c);
1814
1815 bool ret = false;
1816 hb_buffer_t *buffer = c->buffer;
1817 while (buffer->idx < buffer->len && buffer->successful)
1818 {
1819 bool applied = false;
1820 if (accel.digest.may_have (buffer->cur().codepoint) &&
1821 (buffer->cur().mask & c->lookup_mask) &&
1822 c->check_glyph_property (&buffer->cur(), c->lookup_props))
1823 {
1824 applied = accel.apply (c, use_cache);
1825 }
1826
1827 if (applied)
1828 ret = true;
1829 else
1830 (void) buffer->next_glyph ();
1831 }
1832
1833 if (use_cache)
1834 accel.cache_leave (c);
1835
1836 return ret;
1837 }
1838
1839 static inline bool
1840 apply_backward (OT::hb_ot_apply_context_t *c,
1841 const OT::hb_ot_layout_lookup_accelerator_t &accel)
1842 {
1843 bool ret = false;
1844 hb_buffer_t *buffer = c->buffer;
1845 do
1846 {
1847 if (accel.digest.may_have (buffer->cur().codepoint) &&
1848 (buffer->cur().mask & c->lookup_mask) &&
1849 c->check_glyph_property (&buffer->cur(), c->lookup_props))
1850 ret |= accel.apply (c, false);
1851
1852 /* The reverse lookup doesn't "advance" cursor (for good reason). */
1853 buffer->idx--;
1854
1855 }
1856 while ((int) buffer->idx >= 0);
1857 return ret;
1858 }
1859
1860 template <typename Proxy>
1861 static inline bool
1862 apply_string (OT::hb_ot_apply_context_t *c,
1863 const typename Proxy::Lookup &lookup,
1864 const OT::hb_ot_layout_lookup_accelerator_t &accel)
1865 {
1866 bool ret = false;
1867 hb_buffer_t *buffer = c->buffer;
1868
1869 if (unlikely (!buffer->len || !c->lookup_mask))
1870 return ret;
1871
1872 c->set_lookup_props (lookup.get_props ());
1873
1874 if (likely (!lookup.is_reverse ()))
1875 {
1876 /* in/out forward substitution/positioning */
1877 if (!Proxy::always_inplace)
1878 buffer->clear_output ();
1879
1880 buffer->idx = 0;
1881 ret = apply_forward (c, accel);
1882
1883 if (!Proxy::always_inplace)
1884 buffer->sync ();
1885 }
1886 else
1887 {
1888 /* in-place backward substitution/positioning */
1889 assert (!buffer->have_output);
1890 buffer->idx = buffer->len - 1;
1891 ret = apply_backward (c, accel);
1892 }
1893
1894 return ret;
1895 }
1896
1897 template <typename Proxy>
1898 inline void hb_ot_map_t::apply (const Proxy &proxy,
1899 const hb_ot_shape_plan_t *plan,
1900 hb_font_t *font,
1901 hb_buffer_t *buffer) const
1902 {
1903 const unsigned int table_index = proxy.table_index;
1904 unsigned int i = 0;
1905 OT::hb_ot_apply_context_t c (table_index, font, buffer);
1906 c.set_recurse_func (Proxy::Lookup::template dispatch_recurse_func<OT::hb_ot_apply_context_t>);
1907
1908 for (unsigned int stage_index = 0; stage_index < stages[table_index].length; stage_index++)
1909 {
1910 const stage_map_t *stage = &stages[table_index][stage_index];
1911 for (; i < stage->last_lookup; i++)
1912 {
1913 auto &lookup = lookups[table_index][i];
1914
1915 unsigned int lookup_index = lookup.index;
1916 if (!buffer->message (font, "start lookup %d feature '%c%c%c%c'", lookup_index, HB_UNTAG (lookup.feature_tag))) continue;
1917
1918 /* c.digest is a digest of all the current glyphs in the buffer
1919 * (plus some past glyphs).
1920 *
1921 * Only try applying the lookup if there is any overlap. */
1922 if (proxy.accels[lookup_index].digest.may_have (c.digest))
1923 {
1924 c.set_lookup_index (lookup_index);
1925 c.set_lookup_mask (lookup.mask);
1926 c.set_auto_zwj (lookup.auto_zwj);
1927 c.set_auto_zwnj (lookup.auto_zwnj);
1928 c.set_random (lookup.random);
1929 c.set_per_syllable (lookup.per_syllable);
1930
1931 apply_string<Proxy> (&c,
1932 proxy.table.get_lookup (lookup_index),
1933 proxy.accels[lookup_index]);
1934 }
1935 else
1936 (void) buffer->message (font, "skipped lookup %d feature '%c%c%c%c' because no glyph matches", lookup_index, HB_UNTAG (lookup.feature_tag));
1937
1938 (void) buffer->message (font, "end lookup %d feature '%c%c%c%c'", lookup_index, HB_UNTAG (lookup.feature_tag));
1939 }
1940
1941 if (stage->pause_func)
1942 {
1943 if (stage->pause_func (plan, font, buffer))
1944 {
1945 /* Refresh working buffer digest since buffer changed. */
1946 c.digest = buffer->digest ();
1947 }
1948 }
1949 }
1950 }
1951
1952 void hb_ot_map_t::substitute (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
1953 {
1954 GSUBProxy proxy (font->face);
1955 if (!buffer->message (font, "start table GSUB")) return;
1956 apply (proxy, plan, font, buffer);
1957 (void) buffer->message (font, "end table GSUB");
1958 }
1959
1960 void hb_ot_map_t::position (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
1961 {
1962 GPOSProxy proxy (font->face);
1963 if (!buffer->message (font, "start table GPOS")) return;
1964 apply (proxy, plan, font, buffer);
1965 (void) buffer->message (font, "end table GPOS");
1966 }
1967
1968 void
1969 hb_ot_layout_substitute_lookup (OT::hb_ot_apply_context_t *c,
1970 const OT::SubstLookup &lookup,
1971 const OT::hb_ot_layout_lookup_accelerator_t &accel)
1972 {
1973 apply_string<GSUBProxy> (c, lookup, accel);
1974 }
1975
1976 #ifndef HB_NO_BASE
1977 /**
1978 * hb_ot_layout_get_horizontal_baseline_tag_for_script:
1979 * @script: a script tag.
1980 *
1981 * Fetches the dominant horizontal baseline tag used by @script.
1982 *
1983 * Return value: dominant baseline tag for the @script.
1984 *
1985 * Since: 4.0.0
1986 **/
1987 hb_ot_layout_baseline_tag_t
1988 hb_ot_layout_get_horizontal_baseline_tag_for_script (hb_script_t script)
1989 {
1990 /* Keep in sync with hb_ot_layout_get_baseline_with_fallback */
1991 switch ((int) script)
1992 {
1993 /* Unicode-1.1 additions */
1994 case HB_SCRIPT_BENGALI:
1995 case HB_SCRIPT_DEVANAGARI:
1996 case HB_SCRIPT_GUJARATI:
1997 case HB_SCRIPT_GURMUKHI:
1998 /* Unicode-2.0 additions */
1999 case HB_SCRIPT_TIBETAN:
2000 /* Unicode-4.0 additions */
2001 case HB_SCRIPT_LIMBU:
2002 /* Unicode-4.1 additions */
2003 case HB_SCRIPT_SYLOTI_NAGRI:
2004 /* Unicode-5.0 additions */
2005 case HB_SCRIPT_PHAGS_PA:
2006 /* Unicode-5.2 additions */
2007 case HB_SCRIPT_MEETEI_MAYEK:
2008 /* Unicode-6.1 additions */
2009 case HB_SCRIPT_SHARADA:
2010 case HB_SCRIPT_TAKRI:
2011 /* Unicode-7.0 additions */
2012 case HB_SCRIPT_MODI:
2013 case HB_SCRIPT_SIDDHAM:
2014 case HB_SCRIPT_TIRHUTA:
2015 /* Unicode-9.0 additions */
2016 case HB_SCRIPT_MARCHEN:
2017 case HB_SCRIPT_NEWA:
2018 /* Unicode-10.0 additions */
2019 case HB_SCRIPT_SOYOMBO:
2020 case HB_SCRIPT_ZANABAZAR_SQUARE:
2021 /* Unicode-11.0 additions */
2022 case HB_SCRIPT_DOGRA:
2023 case HB_SCRIPT_GUNJALA_GONDI:
2024 /* Unicode-12.0 additions */
2025 case HB_SCRIPT_NANDINAGARI:
2026 return HB_OT_LAYOUT_BASELINE_TAG_HANGING;
2027
2028 /* Unicode-1.1 additions */
2029 case HB_SCRIPT_HANGUL:
2030 case HB_SCRIPT_HAN:
2031 case HB_SCRIPT_HIRAGANA:
2032 case HB_SCRIPT_KATAKANA:
2033 /* Unicode-3.0 additions */
2034 case HB_SCRIPT_BOPOMOFO:
2035 /* Unicode-9.0 additions */
2036 case HB_SCRIPT_TANGUT:
2037 /* Unicode-10.0 additions */
2038 case HB_SCRIPT_NUSHU:
2039 /* Unicode-13.0 additions */
2040 case HB_SCRIPT_KHITAN_SMALL_SCRIPT:
2041 return HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT;
2042
2043 default:
2044 return HB_OT_LAYOUT_BASELINE_TAG_ROMAN;
2045 }
2046 }
2047
2048 /**
2049 * hb_ot_layout_get_baseline:
2050 * @font: a font
2051 * @baseline_tag: a baseline tag
2052 * @direction: text direction.
2053 * @script_tag: script tag.
2054 * @language_tag: language tag, currently unused.
2055 * @coord: (out) (nullable): baseline value if found.
2056 *
2057 * Fetches a baseline value from the face.
2058 *
2059 * Return value: `true` if found baseline value in the font.
2060 *
2061 * Since: 2.6.0
2062 **/
2063 hb_bool_t
2064 hb_ot_layout_get_baseline (hb_font_t *font,
2065 hb_ot_layout_baseline_tag_t baseline_tag,
2066 hb_direction_t direction,
2067 hb_tag_t script_tag,
2068 hb_tag_t language_tag,
2069 hb_position_t *coord /* OUT. May be NULL. */)
2070 {
2071 return font->face->table.BASE->get_baseline (font, baseline_tag, direction, script_tag, language_tag, coord);
2072 }
2073
2074 /**
2075 * hb_ot_layout_get_baseline_with_fallback:
2076 * @font: a font
2077 * @baseline_tag: a baseline tag
2078 * @direction: text direction.
2079 * @script_tag: script tag.
2080 * @language_tag: language tag, currently unused.
2081 * @coord: (out): baseline value if found.
2082 *
2083 * Fetches a baseline value from the face, and synthesizes
2084 * it if the font does not have it.
2085 *
2086 * Since: 4.0.0
2087 **/
2088 void
2089 hb_ot_layout_get_baseline_with_fallback (hb_font_t *font,
2090 hb_ot_layout_baseline_tag_t baseline_tag,
2091 hb_direction_t direction,
2092 hb_tag_t script_tag,
2093 hb_tag_t language_tag,
2094 hb_position_t *coord /* OUT */)
2095 {
2096 if (hb_ot_layout_get_baseline (font,
2097 baseline_tag,
2098 direction,
2099 script_tag,
2100 language_tag,
2101 coord))
2102 return;
2103
2104 /* Synthesize missing baselines.
2105 * See https://www.w3.org/TR/css-inline-3/#baseline-synthesis-fonts
2106 */
2107 switch (baseline_tag)
2108 {
2109 case HB_OT_LAYOUT_BASELINE_TAG_ROMAN:
2110 *coord = 0; // FIXME origin ?
2111 break;
2112
2113 case HB_OT_LAYOUT_BASELINE_TAG_MATH:
2114 {
2115 hb_codepoint_t glyph;
2116 hb_glyph_extents_t extents;
2117 if (HB_DIRECTION_IS_HORIZONTAL (direction) &&
2118 (hb_font_get_nominal_glyph (font, 0x2212u, &glyph) ||
2119 hb_font_get_nominal_glyph (font, '-', &glyph)) &&
2120 hb_font_get_glyph_extents (font, glyph, &extents))
2121 {
2122 *coord = extents.y_bearing + extents.height / 2;
2123 }
2124 else
2125 {
2126 hb_position_t x_height = font->y_scale / 2;
2127 #ifndef HB_NO_METRICS
2128 hb_ot_metrics_get_position_with_fallback (font, HB_OT_METRICS_TAG_X_HEIGHT, &x_height);
2129 #endif
2130 *coord = x_height / 2;
2131 }
2132 }
2133 break;
2134
2135 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT:
2136 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT:
2137 {
2138 hb_position_t embox_top, embox_bottom;
2139
2140 hb_ot_layout_get_baseline_with_fallback (font,
2141 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT,
2142 direction,
2143 script_tag,
2144 language_tag,
2145 &embox_top);
2146 hb_ot_layout_get_baseline_with_fallback (font,
2147 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
2148 direction,
2149 script_tag,
2150 language_tag,
2151 &embox_bottom);
2152
2153 if (baseline_tag == HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT)
2154 *coord = embox_top + (embox_bottom - embox_top) / 10;
2155 else
2156 *coord = embox_bottom + (embox_top - embox_bottom) / 10;
2157 }
2158 break;
2159
2160 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT:
2161 if (hb_ot_layout_get_baseline (font,
2162 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
2163 direction,
2164 script_tag,
2165 language_tag,
2166 coord))
2167 *coord += HB_DIRECTION_IS_HORIZONTAL (direction) ? font->y_scale : font->x_scale;
2168 else
2169 {
2170 hb_font_extents_t font_extents;
2171 hb_font_get_extents_for_direction (font, direction, &font_extents);
2172 *coord = font_extents.ascender;
2173 }
2174 break;
2175
2176 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT:
2177 if (hb_ot_layout_get_baseline (font,
2178 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT,
2179 direction,
2180 script_tag,
2181 language_tag,
2182 coord))
2183 *coord -= HB_DIRECTION_IS_HORIZONTAL (direction) ? font->y_scale : font->x_scale;
2184 else
2185 {
2186 hb_font_extents_t font_extents;
2187 hb_font_get_extents_for_direction (font, direction, &font_extents);
2188 *coord = font_extents.descender;
2189 }
2190 break;
2191
2192 case HB_OT_LAYOUT_BASELINE_TAG_HANGING:
2193 if (HB_DIRECTION_IS_HORIZONTAL (direction))
2194 {
2195 hb_codepoint_t ch;
2196 hb_codepoint_t glyph;
2197 hb_glyph_extents_t extents;
2198
2199 /* Keep in sync with hb_ot_layout_get_horizontal_baseline_for_script */
2200 switch ((int) script_tag)
2201 {
2202 /* Unicode-1.1 additions */
2203 case HB_SCRIPT_BENGALI: ch = 0x0995u; break;
2204 case HB_SCRIPT_DEVANAGARI: ch = 0x0915u; break;
2205 case HB_SCRIPT_GUJARATI: ch = 0x0a95u; break;
2206 case HB_SCRIPT_GURMUKHI: ch = 0x0a15u; break;
2207 /* Unicode-2.0 additions */
2208 case HB_SCRIPT_TIBETAN: ch = 0x0f40u; break;
2209 /* Unicode-4.0 additions */
2210 case HB_SCRIPT_LIMBU: ch = 0x1901u; break;
2211 /* Unicode-4.1 additions */
2212 case HB_SCRIPT_SYLOTI_NAGRI: ch = 0xa807u; break;
2213 /* Unicode-5.0 additions */
2214 case HB_SCRIPT_PHAGS_PA: ch = 0xa840u; break;
2215 /* Unicode-5.2 additions */
2216 case HB_SCRIPT_MEETEI_MAYEK: ch = 0xabc0u; break;
2217 /* Unicode-6.1 additions */
2218 case HB_SCRIPT_SHARADA: ch = 0x11191u; break;
2219 case HB_SCRIPT_TAKRI: ch = 0x1168cu; break;
2220 /* Unicode-7.0 additions */
2221 case HB_SCRIPT_MODI: ch = 0x1160eu;break;
2222 case HB_SCRIPT_SIDDHAM: ch = 0x11590u; break;
2223 case HB_SCRIPT_TIRHUTA: ch = 0x1148fu; break;
2224 /* Unicode-9.0 additions */
2225 case HB_SCRIPT_MARCHEN: ch = 0x11c72u; break;
2226 case HB_SCRIPT_NEWA: ch = 0x1140eu; break;
2227 /* Unicode-10.0 additions */
2228 case HB_SCRIPT_SOYOMBO: ch = 0x11a5cu; break;
2229 case HB_SCRIPT_ZANABAZAR_SQUARE: ch = 0x11a0bu; break;
2230 /* Unicode-11.0 additions */
2231 case HB_SCRIPT_DOGRA: ch = 0x1180au; break;
2232 case HB_SCRIPT_GUNJALA_GONDI: ch = 0x11d6cu; break;
2233 /* Unicode-12.0 additions */
2234 case HB_SCRIPT_NANDINAGARI: ch = 0x119b0u; break;
2235 default: ch = 0; break;
2236 }
2237
2238 if (ch &&
2239 hb_font_get_nominal_glyph (font, ch, &glyph) &&
2240 hb_font_get_glyph_extents (font, glyph, &extents))
2241 *coord = extents.y_bearing;
2242 else
2243 *coord = font->y_scale * 6 / 10; // FIXME makes assumptions about origin
2244 }
2245 else
2246 *coord = font->x_scale * 6 / 10; // FIXME makes assumptions about origin
2247 break;
2248
2249 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_CENTRAL:
2250 {
2251 hb_position_t top, bottom;
2252 hb_ot_layout_get_baseline_with_fallback (font,
2253 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT,
2254 direction,
2255 script_tag,
2256 language_tag,
2257 &top);
2258 hb_ot_layout_get_baseline_with_fallback (font,
2259 HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
2260 direction,
2261 script_tag,
2262 language_tag,
2263 &bottom);
2264 *coord = (top + bottom) / 2;
2265
2266 }
2267 break;
2268
2269 case HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_CENTRAL:
2270 {
2271 hb_position_t top, bottom;
2272 hb_ot_layout_get_baseline_with_fallback (font,
2273 HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT,
2274 direction,
2275 script_tag,
2276 language_tag,
2277 &top);
2278 hb_ot_layout_get_baseline_with_fallback (font,
2279 HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT,
2280 direction,
2281 script_tag,
2282 language_tag,
2283 &bottom);
2284 *coord = (top + bottom) / 2;
2285
2286 }
2287 break;
2288
2289 case _HB_OT_LAYOUT_BASELINE_TAG_MAX_VALUE:
2290 default:
2291 *coord = 0;
2292 break;
2293 }
2294 }
2295
2296 #endif
2297
2298
2299 struct hb_get_glyph_alternates_dispatch_t :
2300 hb_dispatch_context_t<hb_get_glyph_alternates_dispatch_t, unsigned>
2301 {
2302 static return_t default_return_value () { return 0; }
2303 bool stop_sublookup_iteration (return_t r) const { return r; }
2304
2305 private:
2306 template <typename T, typename ...Ts> auto
2307 _dispatch (const T &obj, hb_priority<1>, Ts&&... ds) HB_AUTO_RETURN
2308 ( obj.get_glyph_alternates (std::forward<Ts> (ds)...) )
2309 template <typename T, typename ...Ts> auto
2310 _dispatch (const T &obj, hb_priority<0>, Ts&&... ds) HB_AUTO_RETURN
2311 ( default_return_value () )
2312 public:
2313 template <typename T, typename ...Ts> auto
2314 dispatch (const T &obj, Ts&&... ds) HB_AUTO_RETURN
2315 ( _dispatch (obj, hb_prioritize, std::forward<Ts> (ds)...) )
2316 };
2317
2318 #ifndef HB_NO_LAYOUT_RARELY_USED
2319 /**
2320 * hb_ot_layout_lookup_get_glyph_alternates:
2321 * @face: a face.
2322 * @lookup_index: index of the feature lookup to query.
2323 * @glyph: a glyph id.
2324 * @start_offset: starting offset.
2325 * @alternate_count: (inout) (optional): Input = the maximum number of alternate glyphs to return;
2326 * Output = the actual number of alternate glyphs returned (may be zero).
2327 * @alternate_glyphs: (out caller-allocates) (array length=alternate_count): A glyphs buffer.
2328 * Alternate glyphs associated with the glyph id.
2329 *
2330 * Fetches alternates of a glyph from a given GSUB lookup index.
2331 *
2332 * Return value: Total number of alternates found in the specific lookup index for the given glyph id.
2333 *
2334 * Since: 2.6.8
2335 **/
2336 HB_EXTERN unsigned
2337 hb_ot_layout_lookup_get_glyph_alternates (hb_face_t *face,
2338 unsigned lookup_index,
2339 hb_codepoint_t glyph,
2340 unsigned start_offset,
2341 unsigned *alternate_count /* IN/OUT. May be NULL. */,
2342 hb_codepoint_t *alternate_glyphs /* OUT. May be NULL. */)
2343 {
2344 hb_get_glyph_alternates_dispatch_t c;
2345 const OT::SubstLookup &lookup = face->table.GSUB->table->get_lookup (lookup_index);
2346 auto ret = lookup.dispatch (&c, glyph, start_offset, alternate_count, alternate_glyphs);
2347 if (!ret && alternate_count) *alternate_count = 0;
2348 return ret;
2349 }
2350
2351
2352 struct hb_position_single_dispatch_t :
2353 hb_dispatch_context_t<hb_position_single_dispatch_t, bool>
2354 {
2355 static return_t default_return_value () { return false; }
2356 bool stop_sublookup_iteration (return_t r) const { return r; }
2357
2358 private:
2359 template <typename T, typename ...Ts> auto
2360 _dispatch (const T &obj, hb_priority<1>, Ts&&... ds) HB_AUTO_RETURN
2361 ( obj.position_single (std::forward<Ts> (ds)...) )
2362 template <typename T, typename ...Ts> auto
2363 _dispatch (const T &obj, hb_priority<0>, Ts&&... ds) HB_AUTO_RETURN
2364 ( default_return_value () )
2365 public:
2366 template <typename T, typename ...Ts> auto
2367 dispatch (const T &obj, Ts&&... ds) HB_AUTO_RETURN
2368 ( _dispatch (obj, hb_prioritize, std::forward<Ts> (ds)...) )
2369 };
2370
2371 /**
2372 * hb_ot_layout_lookup_get_optical_bound:
2373 * @font: a font.
2374 * @lookup_index: index of the feature lookup to query.
2375 * @direction: edge of the glyph to query.
2376 * @glyph: a glyph id.
2377 *
2378 * Fetches the optical bound of a glyph positioned at the margin of text.
2379 * The direction identifies which edge of the glyph to query.
2380 *
2381 * Return value: Adjustment value. Negative values mean the glyph will stick out of the margin.
2382 *
2383 * Since: 5.3.0
2384 **/
2385 hb_position_t
2386 hb_ot_layout_lookup_get_optical_bound (hb_font_t *font,
2387 unsigned lookup_index,
2388 hb_direction_t direction,
2389 hb_codepoint_t glyph)
2390 {
2391 const OT::PosLookup &lookup = font->face->table.GPOS->table->get_lookup (lookup_index);
2392 hb_glyph_position_t pos = {0};
2393 hb_position_single_dispatch_t c;
2394 lookup.dispatch (&c, font, direction, glyph, pos);
2395 hb_position_t ret = 0;
2396 switch (direction)
2397 {
2398 case HB_DIRECTION_LTR:
2399 ret = pos.x_offset;
2400 break;
2401 case HB_DIRECTION_RTL:
2402 ret = pos.x_advance - pos.x_offset;
2403 break;
2404 case HB_DIRECTION_TTB:
2405 ret = pos.y_offset;
2406 break;
2407 case HB_DIRECTION_BTT:
2408 ret = pos.y_advance - pos.y_offset;
2409 break;
2410 case HB_DIRECTION_INVALID:
2411 default:
2412 break;
2413 }
2414 return ret;
2415 }
2416 #endif
2417
2418
2419 #endif