1 /*
2 * Copyright © 2011,2014 Google, Inc.
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 *
24 * Google Author(s): Behdad Esfahbod, Roozbeh Pournader
25 */
26
27 #include "hb-private.hh"
28
29 #include "hb-ot.h"
30
31 #include "hb-font-private.hh"
32
33 #include "hb-ot-cmap-table.hh"
34 #include "hb-ot-cbdt-table.hh"
35 #include "hb-ot-glyf-table.hh"
36 #include "hb-ot-head-table.hh"
37 #include "hb-ot-hhea-table.hh"
38 #include "hb-ot-hmtx-table.hh"
39 #include "hb-ot-os2-table.hh"
40 #include "hb-ot-var-hvar-table.hh"
41 //#include "hb-ot-post-table.hh"
42
43
44 struct hb_ot_face_metrics_accelerator_t
45 {
46 unsigned int num_metrics;
47 unsigned int num_advances;
48 unsigned int default_advance;
49 unsigned short ascender;
50 unsigned short descender;
51 unsigned short line_gap;
52 bool has_font_extents;
53
54 const OT::hmtxvmtx *table;
55 hb_blob_t *blob;
56
57 const OT::HVARVVAR *var;
58 hb_blob_t *var_blob;
59
inithb_ot_face_metrics_accelerator_t60 inline void init (hb_face_t *face,
61 hb_tag_t _hea_tag,
62 hb_tag_t _mtx_tag,
63 hb_tag_t _var_tag,
64 hb_tag_t os2_tag,
65 unsigned int default_advance = 0)
66 {
67 this->default_advance = default_advance ? default_advance : face->get_upem ();
68
69 bool got_font_extents = false;
70 if (os2_tag)
71 {
72 hb_blob_t *os2_blob = OT::Sanitizer<OT::os2>::sanitize (face->reference_table (os2_tag));
73 const OT::os2 *os2 = OT::Sanitizer<OT::os2>::lock_instance (os2_blob);
74 #define USE_TYPO_METRICS (1u<<7)
75 if (0 != (os2->fsSelection & USE_TYPO_METRICS))
76 {
77 this->ascender = os2->sTypoAscender;
78 this->descender = os2->sTypoDescender;
79 this->line_gap = os2->sTypoLineGap;
80 got_font_extents = (this->ascender | this->descender) != 0;
81 }
82 hb_blob_destroy (os2_blob);
83 }
84
85 hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));
86 const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);
87 this->num_advances = _hea->numberOfLongMetrics;
88 if (!got_font_extents)
89 {
90 this->ascender = _hea->ascender;
91 this->descender = _hea->descender;
92 this->line_gap = _hea->lineGap;
93 got_font_extents = (this->ascender | this->descender) != 0;
94 }
95 hb_blob_destroy (_hea_blob);
96
97 this->has_font_extents = got_font_extents;
98
99 this->blob = OT::Sanitizer<OT::hmtxvmtx>::sanitize (face->reference_table (_mtx_tag));
100
101 /* Cap num_metrics() and num_advances() based on table length. */
102 unsigned int len = hb_blob_get_length (this->blob);
103 if (unlikely (this->num_advances * 4 > len))
104 this->num_advances = len / 4;
105 this->num_metrics = this->num_advances + (len - 4 * this->num_advances) / 2;
106
107 /* We MUST set num_metrics to zero if num_advances is zero.
108 * Our get_advance() depends on that. */
109 if (unlikely (!this->num_advances))
110 {
111 this->num_metrics = this->num_advances = 0;
112 hb_blob_destroy (this->blob);
113 this->blob = hb_blob_get_empty ();
114 }
115 this->table = OT::Sanitizer<OT::hmtxvmtx>::lock_instance (this->blob);
116
117 this->var_blob = OT::Sanitizer<OT::HVARVVAR>::sanitize (face->reference_table (_var_tag));
118 this->var = OT::Sanitizer<OT::HVARVVAR>::lock_instance (this->var_blob);
119 }
120
finihb_ot_face_metrics_accelerator_t121 inline void fini (void)
122 {
123 hb_blob_destroy (this->blob);
124 hb_blob_destroy (this->var_blob);
125 }
126
get_advancehb_ot_face_metrics_accelerator_t127 inline unsigned int get_advance (hb_codepoint_t glyph,
128 hb_font_t *font) const
129 {
130 if (unlikely (glyph >= this->num_metrics))
131 {
132 /* If this->num_metrics is zero, it means we don't have the metrics table
133 * for this direction: return default advance. Otherwise, it means that the
134 * glyph index is out of bound: return zero. */
135 if (this->num_metrics)
136 return 0;
137 else
138 return this->default_advance;
139 }
140
141 return this->table->longMetric[MIN (glyph, this->num_advances - 1)].advance
142 + this->var->get_advance_var (glyph, font->coords, font->num_coords); // TODO Optimize?!
143 }
144 };
145
146 struct hb_ot_face_glyf_accelerator_t
147 {
148 bool short_offset;
149 unsigned int num_glyphs;
150 const OT::loca *loca;
151 const OT::glyf *glyf;
152 hb_blob_t *loca_blob;
153 hb_blob_t *glyf_blob;
154 unsigned int glyf_len;
155
inithb_ot_face_glyf_accelerator_t156 inline void init (hb_face_t *face)
157 {
158 hb_blob_t *head_blob = OT::Sanitizer<OT::head>::sanitize (face->reference_table (HB_OT_TAG_head));
159 const OT::head *head = OT::Sanitizer<OT::head>::lock_instance (head_blob);
160 if ((unsigned int) head->indexToLocFormat > 1 || head->glyphDataFormat != 0)
161 {
162 /* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */
163 hb_blob_destroy (head_blob);
164 return;
165 }
166 this->short_offset = 0 == head->indexToLocFormat;
167 hb_blob_destroy (head_blob);
168
169 this->loca_blob = OT::Sanitizer<OT::loca>::sanitize (face->reference_table (HB_OT_TAG_loca));
170 this->loca = OT::Sanitizer<OT::loca>::lock_instance (this->loca_blob);
171 this->glyf_blob = OT::Sanitizer<OT::glyf>::sanitize (face->reference_table (HB_OT_TAG_glyf));
172 this->glyf = OT::Sanitizer<OT::glyf>::lock_instance (this->glyf_blob);
173
174 this->num_glyphs = MAX (1u, hb_blob_get_length (this->loca_blob) / (this->short_offset ? 2 : 4)) - 1;
175 this->glyf_len = hb_blob_get_length (this->glyf_blob);
176 }
177
finihb_ot_face_glyf_accelerator_t178 inline void fini (void)
179 {
180 hb_blob_destroy (this->loca_blob);
181 hb_blob_destroy (this->glyf_blob);
182 }
183
get_extentshb_ot_face_glyf_accelerator_t184 inline bool get_extents (hb_codepoint_t glyph,
185 hb_glyph_extents_t *extents) const
186 {
187 if (unlikely (glyph >= this->num_glyphs))
188 return false;
189
190 unsigned int start_offset, end_offset;
191 if (this->short_offset)
192 {
193 start_offset = 2 * this->loca->u.shortsZ[glyph];
194 end_offset = 2 * this->loca->u.shortsZ[glyph + 1];
195 }
196 else
197 {
198 start_offset = this->loca->u.longsZ[glyph];
199 end_offset = this->loca->u.longsZ[glyph + 1];
200 }
201
202 if (start_offset > end_offset || end_offset > this->glyf_len)
203 return false;
204
205 if (end_offset - start_offset < OT::glyfGlyphHeader::static_size)
206 return true; /* Empty glyph; zero extents. */
207
208 const OT::glyfGlyphHeader &glyph_header = OT::StructAtOffset<OT::glyfGlyphHeader> (this->glyf, start_offset);
209
210 extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax);
211 extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax);
212 extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing;
213 extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing;
214
215 return true;
216 }
217 };
218
219 struct hb_ot_face_cbdt_accelerator_t
220 {
221 hb_blob_t *cblc_blob;
222 hb_blob_t *cbdt_blob;
223 const OT::CBLC *cblc;
224 const OT::CBDT *cbdt;
225
226 unsigned int cbdt_len;
227 float upem;
228
inithb_ot_face_cbdt_accelerator_t229 inline void init (hb_face_t *face)
230 {
231 upem = face->get_upem();
232
233 cblc_blob = OT::Sanitizer<OT::CBLC>::sanitize (face->reference_table (HB_OT_TAG_CBLC));
234 cbdt_blob = OT::Sanitizer<OT::CBDT>::sanitize (face->reference_table (HB_OT_TAG_CBDT));
235 cbdt_len = hb_blob_get_length (cbdt_blob);
236
237 if (hb_blob_get_length (cblc_blob) == 0) {
238 cblc = NULL;
239 cbdt = NULL;
240 return; /* Not a bitmap font. */
241 }
242 cblc = OT::Sanitizer<OT::CBLC>::lock_instance (cblc_blob);
243 cbdt = OT::Sanitizer<OT::CBDT>::lock_instance (cbdt_blob);
244
245 }
246
finihb_ot_face_cbdt_accelerator_t247 inline void fini (void)
248 {
249 hb_blob_destroy (this->cblc_blob);
250 hb_blob_destroy (this->cbdt_blob);
251 }
252
get_extentshb_ot_face_cbdt_accelerator_t253 inline bool get_extents (hb_codepoint_t glyph, hb_glyph_extents_t *extents) const
254 {
255 unsigned int x_ppem = upem, y_ppem = upem; /* TODO Use font ppem if available. */
256
257 if (cblc == NULL)
258 return false; // Not a color bitmap font.
259
260 const OT::IndexSubtableRecord *subtable_record = this->cblc->find_table(glyph, &x_ppem, &y_ppem);
261 if (subtable_record == NULL)
262 return false;
263
264 if (subtable_record->get_extents (extents))
265 return true;
266
267 unsigned int image_offset = 0, image_length = 0, image_format = 0;
268 if (!subtable_record->get_image_data (glyph, &image_offset, &image_length, &image_format))
269 return false;
270
271 {
272 /* TODO Move the following into CBDT struct when adding more formats. */
273
274 if (unlikely (image_offset > cbdt_len || cbdt_len - image_offset < image_length))
275 return false;
276
277 switch (image_format)
278 {
279 case 17: {
280 if (unlikely (image_length < OT::GlyphBitmapDataFormat17::min_size))
281 return false;
282
283 const OT::GlyphBitmapDataFormat17& glyphFormat17 =
284 OT::StructAtOffset<OT::GlyphBitmapDataFormat17> (this->cbdt, image_offset);
285 glyphFormat17.glyphMetrics.get_extents (extents);
286 }
287 break;
288 default:
289 // TODO: Support other image formats.
290 return false;
291 }
292 }
293
294 /* Convert to the font units. */
295 extents->x_bearing *= upem / (float) x_ppem;
296 extents->y_bearing *= upem / (float) y_ppem;
297 extents->width *= upem / (float) x_ppem;
298 extents->height *= upem / (float) y_ppem;
299
300 return true;
301 }
302 };
303
304 typedef bool (*hb_cmap_get_glyph_func_t) (const void *obj,
305 hb_codepoint_t codepoint,
306 hb_codepoint_t *glyph);
307
308 template <typename Type>
get_glyph_from(const void * obj,hb_codepoint_t codepoint,hb_codepoint_t * glyph)309 static inline bool get_glyph_from (const void *obj,
310 hb_codepoint_t codepoint,
311 hb_codepoint_t *glyph)
312 {
313 const Type *typed_obj = (const Type *) obj;
314 return typed_obj->get_glyph (codepoint, glyph);
315 }
316
317 template <typename Type>
get_glyph_from_symbol(const void * obj,hb_codepoint_t codepoint,hb_codepoint_t * glyph)318 static inline bool get_glyph_from_symbol (const void *obj,
319 hb_codepoint_t codepoint,
320 hb_codepoint_t *glyph)
321 {
322 const Type *typed_obj = (const Type *) obj;
323 if (likely (typed_obj->get_glyph (codepoint, glyph)))
324 return true;
325
326 if (codepoint <= 0x00FFu)
327 {
328 /* For symbol-encoded OpenType fonts, we duplicate the
329 * U+F000..F0FF range at U+0000..U+00FF. That's what
330 * Windows seems to do, and that's hinted about at:
331 * http://www.microsoft.com/typography/otspec/recom.htm
332 * under "Non-Standard (Symbol) Fonts". */
333 return typed_obj->get_glyph (0xF000u + codepoint, glyph);
334 }
335
336 return false;
337 }
338
339 struct hb_ot_face_cmap_accelerator_t
340 {
341 hb_cmap_get_glyph_func_t get_glyph_func;
342 const void *get_glyph_data;
343 OT::CmapSubtableFormat4::accelerator_t format4_accel;
344
345 const OT::CmapSubtableFormat14 *uvs_table;
346 hb_blob_t *blob;
347
inithb_ot_face_cmap_accelerator_t348 inline void init (hb_face_t *face)
349 {
350 this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));
351 const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
352 const OT::CmapSubtable *subtable = NULL;
353 const OT::CmapSubtableFormat14 *subtable_uvs = NULL;
354
355 bool symbol = false;
356 /* 32-bit subtables. */
357 if (!subtable) subtable = cmap->find_subtable (3, 10);
358 if (!subtable) subtable = cmap->find_subtable (0, 6);
359 if (!subtable) subtable = cmap->find_subtable (0, 4);
360 /* 16-bit subtables. */
361 if (!subtable) subtable = cmap->find_subtable (3, 1);
362 if (!subtable) subtable = cmap->find_subtable (0, 3);
363 if (!subtable) subtable = cmap->find_subtable (0, 2);
364 if (!subtable) subtable = cmap->find_subtable (0, 1);
365 if (!subtable) subtable = cmap->find_subtable (0, 0);
366 if (!subtable)
367 {
368 subtable = cmap->find_subtable (3, 0);
369 if (subtable) symbol = true;
370 }
371 /* Meh. */
372 if (!subtable) subtable = &OT::Null(OT::CmapSubtable);
373
374 /* UVS subtable. */
375 if (!subtable_uvs)
376 {
377 const OT::CmapSubtable *st = cmap->find_subtable (0, 5);
378 if (st && st->u.format == 14)
379 subtable_uvs = &st->u.format14;
380 }
381 /* Meh. */
382 if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtableFormat14);
383
384 this->uvs_table = subtable_uvs;
385
386 this->get_glyph_data = subtable;
387 if (unlikely (symbol))
388 this->get_glyph_func = get_glyph_from_symbol<OT::CmapSubtable>;
389 else
390 switch (subtable->u.format) {
391 /* Accelerate format 4 and format 12. */
392 default: this->get_glyph_func = get_glyph_from<OT::CmapSubtable>; break;
393 case 12: this->get_glyph_func = get_glyph_from<OT::CmapSubtableFormat12>; break;
394 case 4:
395 {
396 this->format4_accel.init (&subtable->u.format4);
397 this->get_glyph_data = &this->format4_accel;
398 this->get_glyph_func = this->format4_accel.get_glyph_func;
399 }
400 break;
401 }
402 }
403
finihb_ot_face_cmap_accelerator_t404 inline void fini (void)
405 {
406 hb_blob_destroy (this->blob);
407 }
408
get_nominal_glyphhb_ot_face_cmap_accelerator_t409 inline bool get_nominal_glyph (hb_codepoint_t unicode,
410 hb_codepoint_t *glyph) const
411 {
412 return this->get_glyph_func (this->get_glyph_data, unicode, glyph);
413 }
414
get_variation_glyphhb_ot_face_cmap_accelerator_t415 inline bool get_variation_glyph (hb_codepoint_t unicode,
416 hb_codepoint_t variation_selector,
417 hb_codepoint_t *glyph) const
418 {
419 switch (this->uvs_table->get_glyph_variant (unicode,
420 variation_selector,
421 glyph))
422 {
423 case OT::GLYPH_VARIANT_NOT_FOUND: return false;
424 case OT::GLYPH_VARIANT_FOUND: return true;
425 case OT::GLYPH_VARIANT_USE_DEFAULT: break;
426 }
427
428 return get_nominal_glyph (unicode, glyph);
429 }
430 };
431
432 struct hb_ot_font_t
433 {
434 hb_ot_face_cmap_accelerator_t cmap;
435 hb_ot_face_metrics_accelerator_t h_metrics;
436 hb_ot_face_metrics_accelerator_t v_metrics;
437 OT::hb_lazy_loader_t<hb_ot_face_glyf_accelerator_t> glyf;
438 OT::hb_lazy_loader_t<hb_ot_face_cbdt_accelerator_t> cbdt;
439 };
440
441
442 static hb_ot_font_t *
_hb_ot_font_create(hb_face_t * face)443 _hb_ot_font_create (hb_face_t *face)
444 {
445 hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
446
447 if (unlikely (!ot_font))
448 return NULL;
449
450 ot_font->cmap.init (face);
451 ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, HB_OT_TAG_HVAR, HB_OT_TAG_os2);
452 ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, HB_OT_TAG_VVAR, HB_TAG_NONE,
453 ot_font->h_metrics.ascender - ot_font->h_metrics.descender); /* TODO Can we do this lazily? */
454 ot_font->glyf.init (face);
455 ot_font->cbdt.init (face);
456
457 return ot_font;
458 }
459
460 static void
_hb_ot_font_destroy(hb_ot_font_t * ot_font)461 _hb_ot_font_destroy (hb_ot_font_t *ot_font)
462 {
463 ot_font->cmap.fini ();
464 ot_font->h_metrics.fini ();
465 ot_font->v_metrics.fini ();
466 ot_font->glyf.fini ();
467 ot_font->cbdt.fini ();
468
469 free (ot_font);
470 }
471
472
473 static hb_bool_t
hb_ot_get_nominal_glyph(hb_font_t * font HB_UNUSED,void * font_data,hb_codepoint_t unicode,hb_codepoint_t * glyph,void * user_data HB_UNUSED)474 hb_ot_get_nominal_glyph (hb_font_t *font HB_UNUSED,
475 void *font_data,
476 hb_codepoint_t unicode,
477 hb_codepoint_t *glyph,
478 void *user_data HB_UNUSED)
479
480 {
481 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
482 return ot_font->cmap.get_nominal_glyph (unicode, glyph);
483 }
484
485 static hb_bool_t
hb_ot_get_variation_glyph(hb_font_t * font HB_UNUSED,void * font_data,hb_codepoint_t unicode,hb_codepoint_t variation_selector,hb_codepoint_t * glyph,void * user_data HB_UNUSED)486 hb_ot_get_variation_glyph (hb_font_t *font HB_UNUSED,
487 void *font_data,
488 hb_codepoint_t unicode,
489 hb_codepoint_t variation_selector,
490 hb_codepoint_t *glyph,
491 void *user_data HB_UNUSED)
492 {
493 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
494 return ot_font->cmap.get_variation_glyph (unicode, variation_selector, glyph);
495 }
496
497 static hb_position_t
hb_ot_get_glyph_h_advance(hb_font_t * font,void * font_data,hb_codepoint_t glyph,void * user_data HB_UNUSED)498 hb_ot_get_glyph_h_advance (hb_font_t *font,
499 void *font_data,
500 hb_codepoint_t glyph,
501 void *user_data HB_UNUSED)
502 {
503 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
504 return font->em_scale_x (ot_font->h_metrics.get_advance (glyph, font));
505 }
506
507 static hb_position_t
hb_ot_get_glyph_v_advance(hb_font_t * font,void * font_data,hb_codepoint_t glyph,void * user_data HB_UNUSED)508 hb_ot_get_glyph_v_advance (hb_font_t *font,
509 void *font_data,
510 hb_codepoint_t glyph,
511 void *user_data HB_UNUSED)
512 {
513 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
514 return font->em_scale_y (-(int) ot_font->v_metrics.get_advance (glyph, font));
515 }
516
517 static hb_bool_t
hb_ot_get_glyph_extents(hb_font_t * font HB_UNUSED,void * font_data,hb_codepoint_t glyph,hb_glyph_extents_t * extents,void * user_data HB_UNUSED)518 hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
519 void *font_data,
520 hb_codepoint_t glyph,
521 hb_glyph_extents_t *extents,
522 void *user_data HB_UNUSED)
523 {
524 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
525 bool ret = ot_font->glyf->get_extents (glyph, extents);
526 if (!ret)
527 ret = ot_font->cbdt->get_extents (glyph, extents);
528 // TODO Hook up side-bearings variations.
529 extents->x_bearing = font->em_scale_x (extents->x_bearing);
530 extents->y_bearing = font->em_scale_y (extents->y_bearing);
531 extents->width = font->em_scale_x (extents->width);
532 extents->height = font->em_scale_y (extents->height);
533 return ret;
534 }
535
536 static hb_bool_t
hb_ot_get_font_h_extents(hb_font_t * font HB_UNUSED,void * font_data,hb_font_extents_t * metrics,void * user_data HB_UNUSED)537 hb_ot_get_font_h_extents (hb_font_t *font HB_UNUSED,
538 void *font_data,
539 hb_font_extents_t *metrics,
540 void *user_data HB_UNUSED)
541 {
542 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
543 metrics->ascender = font->em_scale_y (ot_font->h_metrics.ascender);
544 metrics->descender = font->em_scale_y (ot_font->h_metrics.descender);
545 metrics->line_gap = font->em_scale_y (ot_font->h_metrics.line_gap);
546 // TODO Hook up variations.
547 return ot_font->h_metrics.has_font_extents;
548 }
549
550 static hb_bool_t
hb_ot_get_font_v_extents(hb_font_t * font HB_UNUSED,void * font_data,hb_font_extents_t * metrics,void * user_data HB_UNUSED)551 hb_ot_get_font_v_extents (hb_font_t *font HB_UNUSED,
552 void *font_data,
553 hb_font_extents_t *metrics,
554 void *user_data HB_UNUSED)
555 {
556 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
557 metrics->ascender = font->em_scale_x (ot_font->v_metrics.ascender);
558 metrics->descender = font->em_scale_x (ot_font->v_metrics.descender);
559 metrics->line_gap = font->em_scale_x (ot_font->v_metrics.line_gap);
560 // TODO Hook up variations.
561 return ot_font->v_metrics.has_font_extents;
562 }
563
564 static hb_font_funcs_t *static_ot_funcs = NULL;
565
566 #ifdef HB_USE_ATEXIT
567 static
free_static_ot_funcs(void)568 void free_static_ot_funcs (void)
569 {
570 hb_font_funcs_destroy (static_ot_funcs);
571 }
572 #endif
573
574 static hb_font_funcs_t *
_hb_ot_get_font_funcs(void)575 _hb_ot_get_font_funcs (void)
576 {
577 retry:
578 hb_font_funcs_t *funcs = (hb_font_funcs_t *) hb_atomic_ptr_get (&static_ot_funcs);
579
580 if (unlikely (!funcs))
581 {
582 funcs = hb_font_funcs_create ();
583
584 hb_font_funcs_set_font_h_extents_func (funcs, hb_ot_get_font_h_extents, NULL, NULL);
585 hb_font_funcs_set_font_v_extents_func (funcs, hb_ot_get_font_v_extents, NULL, NULL);
586 hb_font_funcs_set_nominal_glyph_func (funcs, hb_ot_get_nominal_glyph, NULL, NULL);
587 hb_font_funcs_set_variation_glyph_func (funcs, hb_ot_get_variation_glyph, NULL, NULL);
588 hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ot_get_glyph_h_advance, NULL, NULL);
589 hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ot_get_glyph_v_advance, NULL, NULL);
590 //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ot_get_glyph_h_origin, NULL, NULL);
591 //hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ot_get_glyph_v_origin, NULL, NULL);
592 //hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ot_get_glyph_h_kerning, NULL, NULL); TODO
593 //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ot_get_glyph_v_kerning, NULL, NULL);
594 hb_font_funcs_set_glyph_extents_func (funcs, hb_ot_get_glyph_extents, NULL, NULL);
595 //hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ot_get_glyph_contour_point, NULL, NULL); TODO
596 //hb_font_funcs_set_glyph_name_func (funcs, hb_ot_get_glyph_name, NULL, NULL); TODO
597 //hb_font_funcs_set_glyph_from_name_func (funcs, hb_ot_get_glyph_from_name, NULL, NULL); TODO
598
599 hb_font_funcs_make_immutable (funcs);
600
601 if (!hb_atomic_ptr_cmpexch (&static_ot_funcs, NULL, funcs)) {
602 hb_font_funcs_destroy (funcs);
603 goto retry;
604 }
605
606 #ifdef HB_USE_ATEXIT
607 atexit (free_static_ot_funcs); /* First person registers atexit() callback. */
608 #endif
609 };
610
611 return funcs;
612 }
613
614
615 /**
616 * hb_ot_font_set_funcs:
617 *
618 * Since: 0.9.28
619 **/
620 void
hb_ot_font_set_funcs(hb_font_t * font)621 hb_ot_font_set_funcs (hb_font_t *font)
622 {
623 hb_ot_font_t *ot_font = _hb_ot_font_create (font->face);
624 if (unlikely (!ot_font))
625 return;
626
627 hb_font_set_funcs (font,
628 _hb_ot_get_font_funcs (),
629 ot_font,
630 (hb_destroy_func_t) _hb_ot_font_destroy);
631 }
632