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 //#include "hb-ot-post-table.hh"
40
41
42 struct hb_ot_face_metrics_accelerator_t
43 {
44 unsigned int num_metrics;
45 unsigned int num_advances;
46 unsigned int default_advance;
47 unsigned short ascender;
48 unsigned short descender;
49 unsigned short line_gap;
50
51 const OT::_mtx *table;
52 hb_blob_t *blob;
53
54 inline void init (hb_face_t *face,
55 hb_tag_t _hea_tag,
56 hb_tag_t _mtx_tag,
57 hb_tag_t os2_tag)
58 {
59 this->default_advance = face->get_upem ();
60
61 bool got_font_extents = false;
62 if (os2_tag)
63 {
64 hb_blob_t *os2_blob = OT::Sanitizer<OT::os2>::sanitize (face->reference_table (os2_tag));
65 const OT::os2 *os2 = OT::Sanitizer<OT::os2>::lock_instance (os2_blob);
66 #define USE_TYPO_METRICS (1u<<7)
67 if (0 != (os2->fsSelection & USE_TYPO_METRICS))
68 {
69 this->ascender = os2->sTypoAscender;
70 this->descender = os2->sTypoDescender;
71 this->line_gap = os2->sTypoLineGap;
72 got_font_extents = (this->ascender | this->descender) != 0;
73 }
74 hb_blob_destroy (os2_blob);
75 }
76
77 hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));
78 const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);
79 this->num_advances = _hea->numberOfLongMetrics;
80 if (!got_font_extents)
81 {
82 this->ascender = _hea->ascender;
83 this->descender = _hea->descender;
84 this->line_gap = _hea->lineGap;
85 }
86 hb_blob_destroy (_hea_blob);
87
88 this->blob = OT::Sanitizer<OT::_mtx>::sanitize (face->reference_table (_mtx_tag));
89
90 /* Cap num_metrics() and num_advances() based on table length. */
91 unsigned int len = hb_blob_get_length (this->blob);
92 if (unlikely (this->num_advances * 4 > len))
93 this->num_advances = len / 4;
94 this->num_metrics = this->num_advances + (len - 4 * this->num_advances) / 2;
95
96 /* We MUST set num_metrics to zero if num_advances is zero.
97 * Our get_advance() depends on that. */
98 if (unlikely (!this->num_advances))
99 {
100 this->num_metrics = this->num_advances = 0;
101 hb_blob_destroy (this->blob);
102 this->blob = hb_blob_get_empty ();
103 }
104 this->table = OT::Sanitizer<OT::_mtx>::lock_instance (this->blob);
105 }
106
107 inline void fini (void)
108 {
109 hb_blob_destroy (this->blob);
110 }
111
112 inline unsigned int get_advance (hb_codepoint_t glyph) const
113 {
114 if (unlikely (glyph >= this->num_metrics))
115 {
116 /* If this->num_metrics is zero, it means we don't have the metrics table
117 * for this direction: return default advance. Otherwise, it means that the
118 * glyph index is out of bound: return zero. */
119 if (this->num_metrics)
120 return 0;
121 else
122 return this->default_advance;
123 }
124
125 if (glyph >= this->num_advances)
126 glyph = this->num_advances - 1;
127
128 return this->table->longMetric[glyph].advance;
129 }
130 };
131
132 struct hb_ot_face_glyf_accelerator_t
133 {
134 bool short_offset;
135 unsigned int num_glyphs;
136 const OT::loca *loca;
137 const OT::glyf *glyf;
138 hb_blob_t *loca_blob;
139 hb_blob_t *glyf_blob;
140 unsigned int glyf_len;
141
142 inline void init (hb_face_t *face)
143 {
144 hb_blob_t *head_blob = OT::Sanitizer<OT::head>::sanitize (face->reference_table (HB_OT_TAG_head));
145 const OT::head *head = OT::Sanitizer<OT::head>::lock_instance (head_blob);
146 if ((unsigned int) head->indexToLocFormat > 1 || head->glyphDataFormat != 0)
147 {
148 /* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */
149 hb_blob_destroy (head_blob);
150 return;
151 }
152 this->short_offset = 0 == head->indexToLocFormat;
153 hb_blob_destroy (head_blob);
154
155 this->loca_blob = OT::Sanitizer<OT::loca>::sanitize (face->reference_table (HB_OT_TAG_loca));
156 this->loca = OT::Sanitizer<OT::loca>::lock_instance (this->loca_blob);
157 this->glyf_blob = OT::Sanitizer<OT::glyf>::sanitize (face->reference_table (HB_OT_TAG_glyf));
158 this->glyf = OT::Sanitizer<OT::glyf>::lock_instance (this->glyf_blob);
159
160 this->num_glyphs = MAX (1u, hb_blob_get_length (this->loca_blob) / (this->short_offset ? 2 : 4)) - 1;
161 this->glyf_len = hb_blob_get_length (this->glyf_blob);
162 }
163
164 inline void fini (void)
165 {
166 hb_blob_destroy (this->loca_blob);
167 hb_blob_destroy (this->glyf_blob);
168 }
169
170 inline bool get_extents (hb_codepoint_t glyph,
171 hb_glyph_extents_t *extents) const
172 {
173 if (unlikely (glyph >= this->num_glyphs))
174 return false;
175
176 unsigned int start_offset, end_offset;
177 if (this->short_offset)
178 {
179 start_offset = 2 * this->loca->u.shortsZ[glyph];
180 end_offset = 2 * this->loca->u.shortsZ[glyph + 1];
181 }
182 else
183 {
184 start_offset = this->loca->u.longsZ[glyph];
185 end_offset = this->loca->u.longsZ[glyph + 1];
186 }
187
188 if (start_offset > end_offset || end_offset > this->glyf_len)
189 return false;
190
191 if (end_offset - start_offset < OT::glyfGlyphHeader::static_size)
192 return true; /* Empty glyph; zero extents. */
193
194 const OT::glyfGlyphHeader &glyph_header = OT::StructAtOffset<OT::glyfGlyphHeader> (this->glyf, start_offset);
195
196 extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax);
197 extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax);
198 extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing;
199 extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing;
200
201 return true;
202 }
203 };
204
205 typedef bool (*hb_cmap_get_glyph_func_t) (const void *obj,
206 hb_codepoint_t codepoint,
207 hb_codepoint_t *glyph);
208
209 template <typename Type>
210 static inline bool get_glyph_from (const void *obj,
211 hb_codepoint_t codepoint,
212 hb_codepoint_t *glyph)
213 {
214 const Type *typed_obj = (const Type *) obj;
215 return typed_obj->get_glyph (codepoint, glyph);
216 }
217
218 template <typename Type>
219 static inline bool get_glyph_from_symbol (const void *obj,
220 hb_codepoint_t codepoint,
221 hb_codepoint_t *glyph)
222 {
223 const Type *typed_obj = (const Type *) obj;
224 if (likely (typed_obj->get_glyph (codepoint, glyph)))
225 return true;
226
227 if (codepoint <= 0x00FFu)
228 {
229 /* For symbol-encoded OpenType fonts, we duplicate the
230 * U+F000..F0FF range at U+0000..U+00FF. That's what
231 * Windows seems to do, and that's hinted about at:
232 * http://www.microsoft.com/typography/otspec/recom.htm
233 * under "Non-Standard (Symbol) Fonts". */
234 return typed_obj->get_glyph (0xF000u + codepoint, glyph);
235 }
236
237 return false;
238 }
239
240 struct hb_ot_face_cmap_accelerator_t
241 {
242 hb_cmap_get_glyph_func_t get_glyph_func;
243 const void *get_glyph_data;
244 OT::CmapSubtableFormat4::accelerator_t format4_accel;
245
246 const OT::CmapSubtableFormat14 *uvs_table;
247 hb_blob_t *blob;
248
249 inline void init (hb_face_t *face)
250 {
251 this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));
252 const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
253 const OT::CmapSubtable *subtable = NULL;
254 const OT::CmapSubtableFormat14 *subtable_uvs = NULL;
255
256 bool symbol = false;
257 /* 32-bit subtables. */
258 if (!subtable) subtable = cmap->find_subtable (3, 10);
259 if (!subtable) subtable = cmap->find_subtable (0, 6);
260 if (!subtable) subtable = cmap->find_subtable (0, 4);
261 /* 16-bit subtables. */
262 if (!subtable) subtable = cmap->find_subtable (3, 1);
263 if (!subtable) subtable = cmap->find_subtable (0, 3);
264 if (!subtable) subtable = cmap->find_subtable (0, 2);
265 if (!subtable) subtable = cmap->find_subtable (0, 1);
266 if (!subtable) subtable = cmap->find_subtable (0, 0);
267 if (!subtable)(subtable = cmap->find_subtable (3, 0)) && (symbol = true);
268 /* Meh. */
269 if (!subtable) subtable = &OT::Null(OT::CmapSubtable);
270
271 /* UVS subtable. */
272 if (!subtable_uvs)
273 {
274 const OT::CmapSubtable *st = cmap->find_subtable (0, 5);
275 if (st && st->u.format == 14)
276 subtable_uvs = &st->u.format14;
277 }
278 /* Meh. */
279 if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtableFormat14);
280
281 this->uvs_table = subtable_uvs;
282
283 this->get_glyph_data = subtable;
284 if (unlikely (symbol))
285 this->get_glyph_func = get_glyph_from_symbol<OT::CmapSubtable>;
286 else
287 switch (subtable->u.format) {
288 /* Accelerate format 4 and format 12. */
289 default: this->get_glyph_func = get_glyph_from<OT::CmapSubtable>; break;
290 case 12: this->get_glyph_func = get_glyph_from<OT::CmapSubtableFormat12>; break;
291 case 4:
292 {
293 this->format4_accel.init (&subtable->u.format4);
294 this->get_glyph_data = &this->format4_accel;
295 this->get_glyph_func = this->format4_accel.get_glyph_func;
296 }
297 break;
298 }
299 }
300
301 inline void fini (void)
302 {
303 hb_blob_destroy (this->blob);
304 }
305
306 inline bool get_nominal_glyph (hb_codepoint_t unicode,
307 hb_codepoint_t *glyph) const
308 {
309 return this->get_glyph_func (this->get_glyph_data, unicode, glyph);
310 }
311
312 inline bool get_variation_glyph (hb_codepoint_t unicode,
313 hb_codepoint_t variation_selector,
314 hb_codepoint_t *glyph) const
315 {
316 switch (this->uvs_table->get_glyph_variant (unicode,
317 variation_selector,
318 glyph))
319 {
320 case OT::GLYPH_VARIANT_NOT_FOUND: return false;
321 case OT::GLYPH_VARIANT_FOUND: return true;
322 case OT::GLYPH_VARIANT_USE_DEFAULT: break;
323 }
324
325 return get_nominal_glyph (unicode, glyph);
326 }
327 };
328
329 template <typename T>
330 struct hb_lazy_loader_t
331 {
332 inline void init (hb_face_t *face_)
333 {
334 face = face_;
335 instance = NULL;
336 }
337
338 inline void fini (void)
339 {
340 if (instance && instance != &OT::Null(T))
341 {
342 instance->fini();
343 free (instance);
344 }
345 }
346
347 inline const T* operator-> (void) const
348 {
349 retry:
350 T *p = (T *) hb_atomic_ptr_get (&instance);
351 if (unlikely (!p))
352 {
353 p = (T *) calloc (1, sizeof (T));
354 if (unlikely (!p))
355 return &OT::Null(T);
356 p->init (face);
357 if (unlikely (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), NULL, p)))
358 {
359 p->fini ();
360 goto retry;
361 }
362 }
363 return p;
364 }
365
366 private:
367 hb_face_t *face;
368 T *instance;
369 };
370
371 struct hb_ot_font_t
372 {
373 hb_ot_face_cmap_accelerator_t cmap;
374 hb_ot_face_metrics_accelerator_t h_metrics;
375 hb_ot_face_metrics_accelerator_t v_metrics;
376 hb_lazy_loader_t<hb_ot_face_glyf_accelerator_t> glyf;
377 };
378
379
380 static hb_ot_font_t *
381 _hb_ot_font_create (hb_face_t *face)
382 {
383 hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
384
385 if (unlikely (!ot_font))
386 return NULL;
387
388 ot_font->cmap.init (face);
389 ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, HB_OT_TAG_os2);
390 ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, HB_TAG_NONE); /* TODO Can we do this lazily? */
391 ot_font->glyf.init (face);
392
393 return ot_font;
394 }
395
396 static void
397 _hb_ot_font_destroy (hb_ot_font_t *ot_font)
398 {
399 ot_font->cmap.fini ();
400 ot_font->h_metrics.fini ();
401 ot_font->v_metrics.fini ();
402 ot_font->glyf.fini ();
403
404 free (ot_font);
405 }
406
407
408 static hb_bool_t
409 hb_ot_get_nominal_glyph (hb_font_t *font HB_UNUSED,
410 void *font_data,
411 hb_codepoint_t unicode,
412 hb_codepoint_t *glyph,
413 void *user_data HB_UNUSED)
414
415 {
416 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
417 return ot_font->cmap.get_nominal_glyph (unicode, glyph);
418 }
419
420 static hb_bool_t
421 hb_ot_get_variation_glyph (hb_font_t *font HB_UNUSED,
422 void *font_data,
423 hb_codepoint_t unicode,
424 hb_codepoint_t variation_selector,
425 hb_codepoint_t *glyph,
426 void *user_data HB_UNUSED)
427 {
428 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
429 return ot_font->cmap.get_variation_glyph (unicode, variation_selector, glyph);
430 }
431
432 static hb_position_t
433 hb_ot_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
434 void *font_data,
435 hb_codepoint_t glyph,
436 void *user_data HB_UNUSED)
437 {
438 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
439 return font->em_scale_x (ot_font->h_metrics.get_advance (glyph));
440 }
441
442 static hb_position_t
443 hb_ot_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
444 void *font_data,
445 hb_codepoint_t glyph,
446 void *user_data HB_UNUSED)
447 {
448 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
449 return font->em_scale_y (-(int) ot_font->v_metrics.get_advance (glyph));
450 }
451
452 static hb_bool_t
453 hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
454 void *font_data,
455 hb_codepoint_t glyph,
456 hb_glyph_extents_t *extents,
457 void *user_data HB_UNUSED)
458 {
459 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
460 bool ret = ot_font->glyf->get_extents (glyph, extents);
461 extents->x_bearing = font->em_scale_x (extents->x_bearing);
462 extents->y_bearing = font->em_scale_y (extents->y_bearing);
463 extents->width = font->em_scale_x (extents->width);
464 extents->height = font->em_scale_y (extents->height);
465 return ret;
466 }
467
468 static hb_bool_t
469 hb_ot_get_font_h_extents (hb_font_t *font HB_UNUSED,
470 void *font_data,
471 hb_font_extents_t *metrics,
472 void *user_data HB_UNUSED)
473 {
474 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
475 metrics->ascender = font->em_scale_y (ot_font->h_metrics.ascender);
476 metrics->descender = font->em_scale_y (ot_font->h_metrics.descender);
477 metrics->line_gap = font->em_scale_y (ot_font->h_metrics.line_gap);
478 return true;
479 }
480
481 static hb_bool_t
482 hb_ot_get_font_v_extents (hb_font_t *font HB_UNUSED,
483 void *font_data,
484 hb_font_extents_t *metrics,
485 void *user_data HB_UNUSED)
486 {
487 const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
488 metrics->ascender = font->em_scale_x (ot_font->v_metrics.ascender);
489 metrics->descender = font->em_scale_x (ot_font->v_metrics.descender);
490 metrics->line_gap = font->em_scale_x (ot_font->v_metrics.line_gap);
491 return true;
492 }
493
494 static hb_font_funcs_t *static_ot_funcs = NULL;
495
496 #ifdef HB_USE_ATEXIT
497 static
498 void free_static_ot_funcs (void)
499 {
500 hb_font_funcs_destroy (static_ot_funcs);
501 }
502 #endif
503
504 static hb_font_funcs_t *
505 _hb_ot_get_font_funcs (void)
506 {
507 retry:
508 hb_font_funcs_t *funcs = (hb_font_funcs_t *) hb_atomic_ptr_get (&static_ot_funcs);
509
510 if (unlikely (!funcs))
511 {
512 funcs = hb_font_funcs_create ();
513
514 hb_font_funcs_set_font_h_extents_func (funcs, hb_ot_get_font_h_extents, NULL, NULL);
515 hb_font_funcs_set_font_v_extents_func (funcs, hb_ot_get_font_v_extents, NULL, NULL);
516 hb_font_funcs_set_nominal_glyph_func (funcs, hb_ot_get_nominal_glyph, NULL, NULL);
517 hb_font_funcs_set_variation_glyph_func (funcs, hb_ot_get_variation_glyph, NULL, NULL);
518 hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ot_get_glyph_h_advance, NULL, NULL);
519 hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ot_get_glyph_v_advance, NULL, NULL);
520 //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ot_get_glyph_h_origin, NULL, NULL);
521 //hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ot_get_glyph_v_origin, NULL, NULL);
522 //hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ot_get_glyph_h_kerning, NULL, NULL); TODO
523 //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ot_get_glyph_v_kerning, NULL, NULL);
524 hb_font_funcs_set_glyph_extents_func (funcs, hb_ot_get_glyph_extents, NULL, NULL);
525 //hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ot_get_glyph_contour_point, NULL, NULL); TODO
526 //hb_font_funcs_set_glyph_name_func (funcs, hb_ot_get_glyph_name, NULL, NULL); TODO
527 //hb_font_funcs_set_glyph_from_name_func (funcs, hb_ot_get_glyph_from_name, NULL, NULL); TODO
528
529 hb_font_funcs_make_immutable (funcs);
530
531 if (!hb_atomic_ptr_cmpexch (&static_ot_funcs, NULL, funcs)) {
532 hb_font_funcs_destroy (funcs);
533 goto retry;
534 }
535
536 #ifdef HB_USE_ATEXIT
537 atexit (free_static_ot_funcs); /* First person registers atexit() callback. */
538 #endif
539 };
540
541 return funcs;
542 }
543
544
545 /**
546 * hb_ot_font_set_funcs:
547 *
548 * Since: 0.9.28
549 **/
550 void
551 hb_ot_font_set_funcs (hb_font_t *font)
552 {
553 hb_ot_font_t *ot_font = _hb_ot_font_create (font->face);
554 if (unlikely (!ot_font))
555 return;
556
557 hb_font_set_funcs (font,
558 _hb_ot_get_font_funcs (),
559 ot_font,
560 (hb_destroy_func_t) _hb_ot_font_destroy);
561 }