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-glyf-table.hh"
35 #include "hb-ot-head-table.hh"
36 #include "hb-ot-hhea-table.hh"
37 #include "hb-ot-hmtx-table.hh"
38 #include "hb-ot-os2-table.hh"
39
40
41 struct hb_ot_face_metrics_accelerator_t
42 {
43 unsigned int num_metrics;
44 unsigned int num_advances;
45 unsigned int default_advance;
46 unsigned short ascender;
47 unsigned short descender;
48 unsigned short line_gap;
49
50 const OT::_mtx *table;
51 hb_blob_t *blob;
52
inithb_ot_face_metrics_accelerator_t53 inline void init (hb_face_t *face,
54 hb_tag_t _hea_tag,
55 hb_tag_t _mtx_tag,
56 hb_tag_t os2_tag)
57 {
58 this->default_advance = face->get_upem ();
59
60 bool got_font_extents = false;
61 if (os2_tag)
62 {
63 hb_blob_t *os2_blob = OT::Sanitizer<OT::os2>::sanitize (face->reference_table (os2_tag));
64 const OT::os2 *os2 = OT::Sanitizer<OT::os2>::lock_instance (os2_blob);
65 #define USE_TYPO_METRICS (1u<<7)
66 if (0 != (os2->fsSelection & USE_TYPO_METRICS))
67 {
68 this->ascender = os2->sTypoAscender;
69 this->descender = os2->sTypoDescender;
70 this->line_gap = os2->sTypoLineGap;
71 got_font_extents = (this->ascender | this->descender) != 0;
72 }
73 hb_blob_destroy (os2_blob);
74 }
75
76 hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));
77 const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);
78 this->num_advances = _hea->numberOfLongMetrics;
79 if (!got_font_extents)
80 {
81 this->ascender = _hea->ascender;
82 this->descender = _hea->descender;
83 this->line_gap = _hea->lineGap;
84 }
85 hb_blob_destroy (_hea_blob);
86
87 this->blob = OT::Sanitizer<OT::_mtx>::sanitize (face->reference_table (_mtx_tag));
88
89 /* Cap num_metrics() and num_advances() based on table length. */
90 unsigned int len = hb_blob_get_length (this->blob);
91 if (unlikely (this->num_advances * 4 > len))
92 this->num_advances = len / 4;
93 this->num_metrics = this->num_advances + (len - 4 * this->num_advances) / 2;
94
95 /* We MUST set num_metrics to zero if num_advances is zero.
96 * Our get_advance() depends on that. */
97 if (unlikely (!this->num_advances))
98 {
99 this->num_metrics = this->num_advances = 0;
100 hb_blob_destroy (this->blob);
101 this->blob = hb_blob_get_empty ();
102 }
103 this->table = OT::Sanitizer<OT::_mtx>::lock_instance (this->blob);
104 }
105
finihb_ot_face_metrics_accelerator_t106 inline void fini (void)
107 {
108 hb_blob_destroy (this->blob);
109 }
110
get_advancehb_ot_face_metrics_accelerator_t111 inline unsigned int get_advance (hb_codepoint_t glyph) const
112 {
113 if (unlikely (glyph >= this->num_metrics))
114 {
115 /* If this->num_metrics is zero, it means we don't have the metrics table
116 * for this direction: return default advance. Otherwise, it means that the
117 * glyph index is out of bound: return zero. */
118 if (this->num_metrics)
119 return 0;
120 else
121 return this->default_advance;
122 }
123
124 if (glyph >= this->num_advances)
125 glyph = this->num_advances - 1;
126
127 return this->table->longMetric[glyph].advance;
128 }
129 };
130
131 struct hb_ot_face_glyf_accelerator_t
132 {
133 bool short_offset;
134 unsigned int num_glyphs;
135 const OT::loca *loca;
136 const OT::glyf *glyf;
137 hb_blob_t *loca_blob;
138 hb_blob_t *glyf_blob;
139 unsigned int glyf_len;
140
inithb_ot_face_glyf_accelerator_t141 inline void init (hb_face_t *face)
142 {
143 hb_blob_t *head_blob = OT::Sanitizer<OT::head>::sanitize (face->reference_table (HB_OT_TAG_head));
144 const OT::head *head = OT::Sanitizer<OT::head>::lock_instance (head_blob);
145 if ((unsigned int) head->indexToLocFormat > 1 || head->glyphDataFormat != 0)
146 {
147 /* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */
148 hb_blob_destroy (head_blob);
149 return;
150 }
151 this->short_offset = 0 == head->indexToLocFormat;
152 hb_blob_destroy (head_blob);
153
154 this->loca_blob = OT::Sanitizer<OT::loca>::sanitize (face->reference_table (HB_OT_TAG_loca));
155 this->loca = OT::Sanitizer<OT::loca>::lock_instance (this->loca_blob);
156 this->glyf_blob = OT::Sanitizer<OT::glyf>::sanitize (face->reference_table (HB_OT_TAG_glyf));
157 this->glyf = OT::Sanitizer<OT::glyf>::lock_instance (this->glyf_blob);
158
159 this->num_glyphs = MAX (1u, hb_blob_get_length (this->loca_blob) / (this->short_offset ? 2 : 4)) - 1;
160 this->glyf_len = hb_blob_get_length (this->glyf_blob);
161 }
162
finihb_ot_face_glyf_accelerator_t163 inline void fini (void)
164 {
165 hb_blob_destroy (this->loca_blob);
166 hb_blob_destroy (this->glyf_blob);
167 }
168
get_extentshb_ot_face_glyf_accelerator_t169 inline bool get_extents (hb_codepoint_t glyph,
170 hb_glyph_extents_t *extents) const
171 {
172 if (unlikely (glyph >= this->num_glyphs))
173 return false;
174
175 unsigned int start_offset, end_offset;
176 if (this->short_offset)
177 {
178 start_offset = 2 * this->loca->u.shortsZ[glyph];
179 end_offset = 2 * this->loca->u.shortsZ[glyph + 1];
180 }
181 else
182 {
183 start_offset = this->loca->u.longsZ[glyph];
184 end_offset = this->loca->u.longsZ[glyph + 1];
185 }
186
187 if (start_offset > end_offset || end_offset > this->glyf_len)
188 return false;
189
190 if (end_offset - start_offset < OT::glyfGlyphHeader::static_size)
191 return true; /* Empty glyph; zero extents. */
192
193 const OT::glyfGlyphHeader &glyph_header = OT::StructAtOffset<OT::glyfGlyphHeader> (this->glyf, start_offset);
194
195 extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax);
196 extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax);
197 extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing;
198 extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing;
199
200 return true;
201 }
202 };
203
204 typedef bool (*hb_cmap_get_glyph_func_t) (const void *obj,
205 hb_codepoint_t codepoint,
206 hb_codepoint_t *glyph);
207
208 template <typename Type>
get_glyph_from(const void * obj,hb_codepoint_t codepoint,hb_codepoint_t * glyph)209 static inline bool get_glyph_from (const void *obj,
210 hb_codepoint_t codepoint,
211 hb_codepoint_t *glyph)
212 {
213 const Type *typed_obj = (const Type *) obj;
214 return typed_obj->get_glyph (codepoint, glyph);
215 }
216
217 struct hb_ot_face_cmap_accelerator_t
218 {
219 hb_cmap_get_glyph_func_t get_glyph_func;
220 const void *get_glyph_data;
221 OT::CmapSubtableFormat4::accelerator_t format4_accel;
222
223 const OT::CmapSubtableFormat14 *uvs_table;
224 hb_blob_t *blob;
225
inithb_ot_face_cmap_accelerator_t226 inline void init (hb_face_t *face)
227 {
228 this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));
229 const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
230 const OT::CmapSubtable *subtable = NULL;
231 const OT::CmapSubtableFormat14 *subtable_uvs = NULL;
232
233 /* 32-bit subtables. */
234 if (!subtable) subtable = cmap->find_subtable (3, 10);
235 if (!subtable) subtable = cmap->find_subtable (0, 6);
236 if (!subtable) subtable = cmap->find_subtable (0, 4);
237 /* 16-bit subtables. */
238 if (!subtable) subtable = cmap->find_subtable (3, 1);
239 if (!subtable) subtable = cmap->find_subtable (0, 3);
240 if (!subtable) subtable = cmap->find_subtable (0, 2);
241 if (!subtable) subtable = cmap->find_subtable (0, 1);
242 if (!subtable) subtable = cmap->find_subtable (0, 0);
243 if (!subtable) subtable = cmap->find_subtable (3, 0);
244 /* Meh. */
245 if (!subtable) subtable = &OT::Null(OT::CmapSubtable);
246
247 /* UVS subtable. */
248 if (!subtable_uvs)
249 {
250 const OT::CmapSubtable *st = cmap->find_subtable (0, 5);
251 if (st && st->u.format == 14)
252 subtable_uvs = &st->u.format14;
253 }
254 /* Meh. */
255 if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtableFormat14);
256
257 this->uvs_table = subtable_uvs;
258
259 this->get_glyph_data = subtable;
260 switch (subtable->u.format) {
261 /* Accelerate format 4 and format 12. */
262 default: this->get_glyph_func = get_glyph_from<OT::CmapSubtable>; break;
263 case 12: this->get_glyph_func = get_glyph_from<OT::CmapSubtableFormat12>; break;
264 case 4:
265 {
266 this->format4_accel.init (&subtable->u.format4);
267 this->get_glyph_data = &this->format4_accel;
268 this->get_glyph_func = this->format4_accel.get_glyph_func;
269 }
270 break;
271 }
272 }
273
finihb_ot_face_cmap_accelerator_t274 inline void fini (void)
275 {
276 hb_blob_destroy (this->blob);
277 }
278
get_nominal_glyphhb_ot_face_cmap_accelerator_t279 inline bool get_nominal_glyph (hb_codepoint_t unicode,
280 hb_codepoint_t *glyph) const
281 {
282 return this->get_glyph_func (this->get_glyph_data, unicode, glyph);
283 }
284
get_variation_glyphhb_ot_face_cmap_accelerator_t285 inline bool get_variation_glyph (hb_codepoint_t unicode,
286 hb_codepoint_t variation_selector,
287 hb_codepoint_t *glyph) const
288 {
289 switch (this->uvs_table->get_glyph_variant (unicode,
290 variation_selector,
291 glyph))
292 {
293 case OT::GLYPH_VARIANT_NOT_FOUND: return false;
294 case OT::GLYPH_VARIANT_FOUND: return true;
295 case OT::GLYPH_VARIANT_USE_DEFAULT: break;
296 }
297
298 return get_nominal_glyph (unicode, glyph);
299 }
300 };
301
302
303 struct hb_ot_font_t
304 {
305 hb_ot_face_cmap_accelerator_t cmap;
306 hb_ot_face_metrics_accelerator_t h_metrics;
307 hb_ot_face_metrics_accelerator_t v_metrics;
308 hb_ot_face_glyf_accelerator_t glyf;
309 };
310
311
312 static hb_ot_font_t *
_hb_ot_font_create(hb_face_t * face)313 _hb_ot_font_create (hb_face_t *face)
314 {
315 hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
316
317 if (unlikely (!ot_font))
318 return NULL;
319
320 ot_font->cmap.init (face);
321 ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, HB_OT_TAG_os2);
322 ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, HB_TAG_NONE); /* TODO Can we do this lazily? */
323 ot_font->glyf.init (face);
324
325 return ot_font;
326 }
327
328 static void
_hb_ot_font_destroy(hb_ot_font_t * ot_font)329 _hb_ot_font_destroy (hb_ot_font_t *ot_font)
330 {
331 ot_font->cmap.fini ();
332 ot_font->h_metrics.fini ();
333 ot_font->v_metrics.fini ();
334 ot_font->glyf.fini ();
335
336 free (ot_font);
337 }
338
339
340 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)341 hb_ot_get_nominal_glyph (hb_font_t *font HB_UNUSED,
342 void *font_data,
343 hb_codepoint_t unicode,
344 hb_codepoint_t *glyph,
345 void *user_data HB_UNUSED)
346
347 {
348 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
349 return ot_font->cmap.get_nominal_glyph (unicode, glyph);
350 }
351
352 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)353 hb_ot_get_variation_glyph (hb_font_t *font HB_UNUSED,
354 void *font_data,
355 hb_codepoint_t unicode,
356 hb_codepoint_t variation_selector,
357 hb_codepoint_t *glyph,
358 void *user_data HB_UNUSED)
359 {
360 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
361 return ot_font->cmap.get_variation_glyph (unicode, variation_selector, glyph);
362 }
363
364 static hb_position_t
hb_ot_get_glyph_h_advance(hb_font_t * font HB_UNUSED,void * font_data,hb_codepoint_t glyph,void * user_data HB_UNUSED)365 hb_ot_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
366 void *font_data,
367 hb_codepoint_t glyph,
368 void *user_data HB_UNUSED)
369 {
370 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
371 return font->em_scale_x (ot_font->h_metrics.get_advance (glyph));
372 }
373
374 static hb_position_t
hb_ot_get_glyph_v_advance(hb_font_t * font HB_UNUSED,void * font_data,hb_codepoint_t glyph,void * user_data HB_UNUSED)375 hb_ot_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
376 void *font_data,
377 hb_codepoint_t glyph,
378 void *user_data HB_UNUSED)
379 {
380 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
381 return font->em_scale_y (-(int) ot_font->v_metrics.get_advance (glyph));
382 }
383
384 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)385 hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
386 void *font_data,
387 hb_codepoint_t glyph,
388 hb_glyph_extents_t *extents,
389 void *user_data HB_UNUSED)
390 {
391 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
392 bool ret = ot_font->glyf.get_extents (glyph, extents);
393 extents->x_bearing = font->em_scale_x (extents->x_bearing);
394 extents->y_bearing = font->em_scale_y (extents->y_bearing);
395 extents->width = font->em_scale_x (extents->width);
396 extents->height = font->em_scale_y (extents->height);
397 return ret;
398 }
399
400 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)401 hb_ot_get_font_h_extents (hb_font_t *font HB_UNUSED,
402 void *font_data,
403 hb_font_extents_t *metrics,
404 void *user_data HB_UNUSED)
405 {
406 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
407 metrics->ascender = font->em_scale_y (ot_font->h_metrics.ascender);
408 metrics->descender = font->em_scale_y (ot_font->h_metrics.descender);
409 metrics->line_gap = font->em_scale_y (ot_font->h_metrics.line_gap);
410 return true;
411 }
412
413 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)414 hb_ot_get_font_v_extents (hb_font_t *font HB_UNUSED,
415 void *font_data,
416 hb_font_extents_t *metrics,
417 void *user_data HB_UNUSED)
418 {
419 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
420 metrics->ascender = font->em_scale_x (ot_font->v_metrics.ascender);
421 metrics->descender = font->em_scale_x (ot_font->v_metrics.descender);
422 metrics->line_gap = font->em_scale_x (ot_font->v_metrics.line_gap);
423 return true;
424 }
425
426 static hb_font_funcs_t *static_ot_funcs = NULL;
427
428 #ifdef HB_USE_ATEXIT
429 static
free_static_ot_funcs(void)430 void free_static_ot_funcs (void)
431 {
432 hb_font_funcs_destroy (static_ot_funcs);
433 }
434 #endif
435
436 static hb_font_funcs_t *
_hb_ot_get_font_funcs(void)437 _hb_ot_get_font_funcs (void)
438 {
439 retry:
440 hb_font_funcs_t *funcs = (hb_font_funcs_t *) hb_atomic_ptr_get (&static_ot_funcs);
441
442 if (unlikely (!funcs))
443 {
444 funcs = hb_font_funcs_create ();
445
446 hb_font_funcs_set_font_h_extents_func (funcs, hb_ot_get_font_h_extents, NULL, NULL);
447 hb_font_funcs_set_font_v_extents_func (funcs, hb_ot_get_font_v_extents, NULL, NULL);
448 hb_font_funcs_set_nominal_glyph_func (funcs, hb_ot_get_nominal_glyph, NULL, NULL);
449 hb_font_funcs_set_variation_glyph_func (funcs, hb_ot_get_variation_glyph, NULL, NULL);
450 hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ot_get_glyph_h_advance, NULL, NULL);
451 hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ot_get_glyph_v_advance, NULL, NULL);
452 //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ot_get_glyph_h_origin, NULL, NULL);
453 //hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ot_get_glyph_v_origin, NULL, NULL);
454 //hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ot_get_glyph_h_kerning, NULL, NULL); TODO
455 //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ot_get_glyph_v_kerning, NULL, NULL);
456 hb_font_funcs_set_glyph_extents_func (funcs, hb_ot_get_glyph_extents, NULL, NULL);
457 //hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ot_get_glyph_contour_point, NULL, NULL); TODO
458 //hb_font_funcs_set_glyph_name_func (funcs, hb_ot_get_glyph_name, NULL, NULL); TODO
459 //hb_font_funcs_set_glyph_from_name_func (funcs, hb_ot_get_glyph_from_name, NULL, NULL); TODO
460
461 hb_font_funcs_make_immutable (funcs);
462
463 if (!hb_atomic_ptr_cmpexch (&static_ot_funcs, NULL, funcs)) {
464 hb_font_funcs_destroy (funcs);
465 goto retry;
466 }
467
468 #ifdef HB_USE_ATEXIT
469 atexit (free_static_ot_funcs); /* First person registers atexit() callback. */
470 #endif
471 };
472
473 return funcs;
474 }
475
476
477 /**
478 * hb_ot_font_set_funcs:
479 *
480 * Since: 0.9.28
481 **/
482 void
hb_ot_font_set_funcs(hb_font_t * font)483 hb_ot_font_set_funcs (hb_font_t *font)
484 {
485 hb_ot_font_t *ot_font = _hb_ot_font_create (font->face);
486 if (unlikely (!ot_font))
487 return;
488
489 hb_font_set_funcs (font,
490 _hb_ot_get_font_funcs (),
491 ot_font,
492 (hb_destroy_func_t) _hb_ot_font_destroy);
493 }
494