1 /*
2 * Copyright © 2009,2010 Red Hat, Inc.
3 * Copyright © 2010,2011,2012 Google, Inc.
4 *
5 * This is part of HarfBuzz, a text shaping library.
6 *
7 * Permission is hereby granted, without written agreement and without
8 * license or royalty fees, to use, copy, modify, and distribute this
9 * software and its documentation for any purpose, provided that the
10 * above copyright notice and the following two paragraphs appear in
11 * all copies of this software.
12 *
13 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17 * DAMAGE.
18 *
19 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
22 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24 *
25 * Red Hat Author(s): Behdad Esfahbod
26 * Google Author(s): Behdad Esfahbod
27 */
28
29 #define HB_SHAPER ot
30 #define hb_ot_shaper_face_data_t hb_ot_layout_t
31 #define hb_ot_shaper_shape_plan_data_t hb_ot_shape_plan_t
32 #include "hb-shaper-impl-private.hh"
33
34 #include "hb-ot-shape-private.hh"
35 #include "hb-ot-shape-complex-private.hh"
36 #include "hb-ot-shape-fallback-private.hh"
37 #include "hb-ot-shape-normalize-private.hh"
38
39 #include "hb-ot-layout-private.hh"
40 #include "hb-unicode-private.hh"
41 #include "hb-set-private.hh"
42
43
44 static hb_tag_t common_features[] = {
45 HB_TAG('c','c','m','p'),
46 HB_TAG('l','o','c','l'),
47 HB_TAG('m','a','r','k'),
48 HB_TAG('m','k','m','k'),
49 HB_TAG('r','l','i','g'),
50 };
51
52
53 static hb_tag_t horizontal_features[] = {
54 HB_TAG('c','a','l','t'),
55 HB_TAG('c','l','i','g'),
56 HB_TAG('c','u','r','s'),
57 HB_TAG('k','e','r','n'),
58 HB_TAG('l','i','g','a'),
59 HB_TAG('r','c','l','t'),
60 };
61
62
63
64 static void
65 hb_ot_shape_collect_features (hb_ot_shape_planner_t *planner,
66 const hb_segment_properties_t *props,
67 const hb_feature_t *user_features,
68 unsigned int num_user_features)
69 {
70 hb_ot_map_builder_t *map = &planner->map;
71
72 map->add_global_bool_feature (HB_TAG('r','v','r','n'));
73 map->add_gsub_pause (NULL);
74
75 switch (props->direction) {
76 case HB_DIRECTION_LTR:
77 map->add_global_bool_feature (HB_TAG ('l','t','r','a'));
78 map->add_global_bool_feature (HB_TAG ('l','t','r','m'));
79 break;
80 case HB_DIRECTION_RTL:
81 map->add_global_bool_feature (HB_TAG ('r','t','l','a'));
82 map->add_feature (HB_TAG ('r','t','l','m'), 1, F_NONE);
83 break;
84 case HB_DIRECTION_TTB:
85 case HB_DIRECTION_BTT:
86 case HB_DIRECTION_INVALID:
87 default:
88 break;
89 }
90
91 map->add_feature (HB_TAG ('f','r','a','c'), 1, F_NONE);
92 map->add_feature (HB_TAG ('n','u','m','r'), 1, F_NONE);
93 map->add_feature (HB_TAG ('d','n','o','m'), 1, F_NONE);
94
95 if (planner->shaper->collect_features)
96 planner->shaper->collect_features (planner);
97
98 for (unsigned int i = 0; i < ARRAY_LENGTH (common_features); i++)
99 map->add_global_bool_feature (common_features[i]);
100
101 if (HB_DIRECTION_IS_HORIZONTAL (props->direction))
102 for (unsigned int i = 0; i < ARRAY_LENGTH (horizontal_features); i++)
103 map->add_feature (horizontal_features[i], 1, F_GLOBAL |
104 (horizontal_features[i] == HB_TAG('k','e','r','n') ?
105 F_HAS_FALLBACK : F_NONE));
106 else
107 {
108 /* We really want to find a 'vert' feature if there's any in the font, no
109 * matter which script/langsys it is listed (or not) under.
110 * See various bugs referenced from:
111 * https://github.com/behdad/harfbuzz/issues/63 */
112 map->add_feature (HB_TAG ('v','e','r','t'), 1, F_GLOBAL | F_GLOBAL_SEARCH);
113 }
114
115 if (planner->shaper->override_features)
116 planner->shaper->override_features (planner);
117
118 for (unsigned int i = 0; i < num_user_features; i++) {
119 const hb_feature_t *feature = &user_features[i];
120 map->add_feature (feature->tag, feature->value,
121 (feature->start == 0 && feature->end == (unsigned int) -1) ?
122 F_GLOBAL : F_NONE);
123 }
124 }
125
126
127 /*
128 * shaper face data
129 */
130
131 hb_ot_shaper_face_data_t *
132 _hb_ot_shaper_face_data_create (hb_face_t *face)
133 {
134 return _hb_ot_layout_create (face);
135 }
136
137 void
138 _hb_ot_shaper_face_data_destroy (hb_ot_shaper_face_data_t *data)
139 {
140 _hb_ot_layout_destroy (data);
141 }
142
143
144 /*
145 * shaper font data
146 */
147
148 struct hb_ot_shaper_font_data_t {};
149
150 hb_ot_shaper_font_data_t *
151 _hb_ot_shaper_font_data_create (hb_font_t *font HB_UNUSED)
152 {
153 return (hb_ot_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
154 }
155
156 void
157 _hb_ot_shaper_font_data_destroy (hb_ot_shaper_font_data_t *data)
158 {
159 }
160
161
162 /*
163 * shaper shape_plan data
164 */
165
166 hb_ot_shaper_shape_plan_data_t *
167 _hb_ot_shaper_shape_plan_data_create (hb_shape_plan_t *shape_plan,
168 const hb_feature_t *user_features,
169 unsigned int num_user_features,
170 const int *coords,
171 unsigned int num_coords)
172 {
173 hb_ot_shape_plan_t *plan = (hb_ot_shape_plan_t *) calloc (1, sizeof (hb_ot_shape_plan_t));
174 if (unlikely (!plan))
175 return NULL;
176
177 hb_ot_shape_planner_t planner (shape_plan);
178
179 planner.shaper = hb_ot_shape_complex_categorize (&planner);
180
181 hb_ot_shape_collect_features (&planner, &shape_plan->props,
182 user_features, num_user_features);
183
184 planner.compile (*plan, coords, num_coords);
185
186 if (plan->shaper->data_create) {
187 plan->data = plan->shaper->data_create (plan);
188 if (unlikely (!plan->data))
189 return NULL;
190 }
191
192 return plan;
193 }
194
195 void
196 _hb_ot_shaper_shape_plan_data_destroy (hb_ot_shaper_shape_plan_data_t *plan)
197 {
198 if (plan->shaper->data_destroy)
199 plan->shaper->data_destroy (const_cast<void *> (plan->data));
200
201 plan->finish ();
202
203 free (plan);
204 }
205
206
207 /*
208 * shaper
209 */
210
211 struct hb_ot_shape_context_t
212 {
213 hb_ot_shape_plan_t *plan;
214 hb_font_t *font;
215 hb_face_t *face;
216 hb_buffer_t *buffer;
217 const hb_feature_t *user_features;
218 unsigned int num_user_features;
219
220 /* Transient stuff */
221 bool fallback_positioning;
222 bool fallback_glyph_classes;
223 hb_direction_t target_direction;
224 };
225
226
227
228 /* Main shaper */
229
230
231 /* Prepare */
232
233 static void
234 hb_set_unicode_props (hb_buffer_t *buffer)
235 {
236 unsigned int count = buffer->len;
237 hb_glyph_info_t *info = buffer->info;
238 for (unsigned int i = 0; i < count; i++)
239 _hb_glyph_info_set_unicode_props (&info[i], buffer);
240 }
241
242 static void
243 hb_insert_dotted_circle (hb_buffer_t *buffer, hb_font_t *font)
244 {
245 if (!(buffer->flags & HB_BUFFER_FLAG_BOT) ||
246 buffer->context_len[0] ||
247 _hb_glyph_info_get_general_category (&buffer->info[0]) !=
248 HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)
249 return;
250
251 if (!font->has_glyph (0x25CCu))
252 return;
253
254 hb_glyph_info_t dottedcircle = {0};
255 dottedcircle.codepoint = 0x25CCu;
256 _hb_glyph_info_set_unicode_props (&dottedcircle, buffer);
257
258 buffer->clear_output ();
259
260 buffer->idx = 0;
261 hb_glyph_info_t info = dottedcircle;
262 info.cluster = buffer->cur().cluster;
263 info.mask = buffer->cur().mask;
264 buffer->output_info (info);
265 while (buffer->idx < buffer->len && !buffer->in_error)
266 buffer->next_glyph ();
267
268 buffer->swap_buffers ();
269 }
270
271 static void
272 hb_form_clusters (hb_buffer_t *buffer)
273 {
274 if (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_NON_ASCII) ||
275 buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES)
276 return;
277
278 /* Loop duplicated in hb_ensure_native_direction(), and in _hb-coretext.cc */
279 unsigned int base = 0;
280 unsigned int count = buffer->len;
281 hb_glyph_info_t *info = buffer->info;
282 for (unsigned int i = 1; i < count; i++)
283 {
284 if (likely (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])) &&
285 !_hb_glyph_info_is_joiner (&info[i])))
286 {
287 buffer->merge_clusters (base, i);
288 base = i;
289 }
290 }
291 buffer->merge_clusters (base, count);
292 }
293
294 static void
295 hb_ensure_native_direction (hb_buffer_t *buffer)
296 {
297 hb_direction_t direction = buffer->props.direction;
298
299 /* TODO vertical:
300 * The only BTT vertical script is Ogham, but it's not clear to me whether OpenType
301 * Ogham fonts are supposed to be implemented BTT or not. Need to research that
302 * first. */
303 if ((HB_DIRECTION_IS_HORIZONTAL (direction) && direction != hb_script_get_horizontal_direction (buffer->props.script)) ||
304 (HB_DIRECTION_IS_VERTICAL (direction) && direction != HB_DIRECTION_TTB))
305 {
306 /* Same loop as hb_form_clusters().
307 * Since form_clusters() merged clusters already, we don't merge. */
308 unsigned int base = 0;
309 unsigned int count = buffer->len;
310 hb_glyph_info_t *info = buffer->info;
311 for (unsigned int i = 1; i < count; i++)
312 {
313 if (likely (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i]))))
314 {
315 if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
316 buffer->merge_clusters (base, i);
317 buffer->reverse_range (base, i);
318
319 base = i;
320 }
321 }
322 if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
323 buffer->merge_clusters (base, count);
324 buffer->reverse_range (base, count);
325
326 buffer->reverse ();
327
328 buffer->props.direction = HB_DIRECTION_REVERSE (buffer->props.direction);
329 }
330 }
331
332
333 /* Substitute */
334
335 static inline void
336 hb_ot_mirror_chars (hb_ot_shape_context_t *c)
337 {
338 if (HB_DIRECTION_IS_FORWARD (c->target_direction))
339 return;
340
341 hb_buffer_t *buffer = c->buffer;
342 hb_unicode_funcs_t *unicode = buffer->unicode;
343 hb_mask_t rtlm_mask = c->plan->rtlm_mask;
344
345 unsigned int count = buffer->len;
346 hb_glyph_info_t *info = buffer->info;
347 for (unsigned int i = 0; i < count; i++) {
348 hb_codepoint_t codepoint = unicode->mirroring (info[i].codepoint);
349 if (likely (codepoint == info[i].codepoint || !c->font->has_glyph (codepoint)))
350 info[i].mask |= rtlm_mask;
351 else
352 info[i].codepoint = codepoint;
353 }
354 }
355
356 static inline void
357 hb_ot_shape_setup_masks_fraction (hb_ot_shape_context_t *c)
358 {
359 if (!(c->buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_NON_ASCII) ||
360 !c->plan->has_frac)
361 return;
362
363 hb_buffer_t *buffer = c->buffer;
364
365 /* TODO look in pre/post context text also. */
366 unsigned int count = buffer->len;
367 hb_glyph_info_t *info = buffer->info;
368 for (unsigned int i = 0; i < count; i++)
369 {
370 if (info[i].codepoint == 0x2044u) /* FRACTION SLASH */
371 {
372 unsigned int start = i, end = i + 1;
373 while (start &&
374 _hb_glyph_info_get_general_category (&info[start - 1]) ==
375 HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER)
376 start--;
377 while (end < count &&
378 _hb_glyph_info_get_general_category (&info[end]) ==
379 HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER)
380 end++;
381
382 for (unsigned int j = start; j < i; j++)
383 info[j].mask |= c->plan->numr_mask | c->plan->frac_mask;
384 info[i].mask |= c->plan->frac_mask;
385 for (unsigned int j = i + 1; j < end; j++)
386 info[j].mask |= c->plan->frac_mask | c->plan->dnom_mask;
387
388 i = end - 1;
389 }
390 }
391 }
392
393 static inline void
394 hb_ot_shape_initialize_masks (hb_ot_shape_context_t *c)
395 {
396 hb_ot_map_t *map = &c->plan->map;
397 hb_buffer_t *buffer = c->buffer;
398
399 hb_mask_t global_mask = map->get_global_mask ();
400 buffer->reset_masks (global_mask);
401 }
402
403 static inline void
404 hb_ot_shape_setup_masks (hb_ot_shape_context_t *c)
405 {
406 hb_ot_map_t *map = &c->plan->map;
407 hb_buffer_t *buffer = c->buffer;
408
409 hb_ot_shape_setup_masks_fraction (c);
410
411 if (c->plan->shaper->setup_masks)
412 c->plan->shaper->setup_masks (c->plan, buffer, c->font);
413
414 for (unsigned int i = 0; i < c->num_user_features; i++)
415 {
416 const hb_feature_t *feature = &c->user_features[i];
417 if (!(feature->start == 0 && feature->end == (unsigned int)-1)) {
418 unsigned int shift;
419 hb_mask_t mask = map->get_mask (feature->tag, &shift);
420 buffer->set_masks (feature->value << shift, mask, feature->start, feature->end);
421 }
422 }
423 }
424
425 static void
426 hb_ot_zero_width_default_ignorables (hb_ot_shape_context_t *c)
427 {
428 hb_buffer_t *buffer = c->buffer;
429
430 if (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_DEFAULT_IGNORABLES) ||
431 (buffer->flags & HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES))
432 return;
433
434 unsigned int count = buffer->len;
435 hb_glyph_info_t *info = buffer->info;
436 hb_glyph_position_t *pos = buffer->pos;
437 unsigned int i = 0;
438 for (i = 0; i < count; i++)
439 if (unlikely (_hb_glyph_info_is_default_ignorable (&info[i])))
440 pos[i].x_advance = pos[i].y_advance = pos[i].x_offset = pos[i].y_offset = 0;
441 }
442
443 static void
444 hb_ot_hide_default_ignorables (hb_ot_shape_context_t *c)
445 {
446 hb_buffer_t *buffer = c->buffer;
447
448 if (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_DEFAULT_IGNORABLES) ||
449 (buffer->flags & HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES))
450 return;
451
452 unsigned int count = buffer->len;
453 hb_glyph_info_t *info = buffer->info;
454 hb_glyph_position_t *pos = buffer->pos;
455 unsigned int i = 0;
456 for (i = 0; i < count; i++)
457 {
458 if (unlikely (_hb_glyph_info_is_default_ignorable (&info[i])))
459 break;
460 }
461
462 /* No default-ignorables found; return. */
463 if (i == count)
464 return;
465
466 hb_codepoint_t space;
467 if (c->font->get_nominal_glyph (' ', &space))
468 {
469 /* Replace default-ignorables with a zero-advance space glyph. */
470 for (/*continue*/; i < count; i++)
471 {
472 if (_hb_glyph_info_is_default_ignorable (&info[i]))
473 info[i].codepoint = space;
474 }
475 }
476 else
477 {
478 /* Merge clusters and delete default-ignorables.
479 * NOTE! We can't use out-buffer as we have positioning data. */
480 unsigned int j = i;
481 for (; i < count; i++)
482 {
483 if (_hb_glyph_info_is_default_ignorable (&info[i]))
484 {
485 /* Merge clusters.
486 * Same logic as buffer->delete_glyph(), but for in-place removal. */
487
488 unsigned int cluster = info[i].cluster;
489 if (i + 1 < count && cluster == info[i + 1].cluster)
490 continue; /* Cluster survives; do nothing. */
491
492 if (j)
493 {
494 /* Merge cluster backward. */
495 if (cluster < info[j - 1].cluster)
496 {
497 unsigned int old_cluster = info[j - 1].cluster;
498 for (unsigned k = j; k && info[k - 1].cluster == old_cluster; k--)
499 info[k - 1].cluster = cluster;
500 }
501 continue;
502 }
503
504 if (i + 1 < count)
505 buffer->merge_clusters (i, i + 2); /* Merge cluster forward. */
506
507 continue;
508 }
509
510 if (j != i)
511 {
512 info[j] = info[i];
513 pos[j] = pos[i];
514 }
515 j++;
516 }
517 buffer->len = j;
518 }
519 }
520
521
522 static inline void
523 hb_ot_map_glyphs_fast (hb_buffer_t *buffer)
524 {
525 /* Normalization process sets up glyph_index(), we just copy it. */
526 unsigned int count = buffer->len;
527 hb_glyph_info_t *info = buffer->info;
528 for (unsigned int i = 0; i < count; i++)
529 info[i].codepoint = info[i].glyph_index();
530
531 buffer->content_type = HB_BUFFER_CONTENT_TYPE_GLYPHS;
532 }
533
534 static inline void
535 hb_synthesize_glyph_classes (hb_ot_shape_context_t *c)
536 {
537 unsigned int count = c->buffer->len;
538 hb_glyph_info_t *info = c->buffer->info;
539 for (unsigned int i = 0; i < count; i++)
540 {
541 hb_ot_layout_glyph_props_flags_t klass;
542
543 /* Never mark default-ignorables as marks.
544 * They won't get in the way of lookups anyway,
545 * but having them as mark will cause them to be skipped
546 * over if the lookup-flag says so, but at least for the
547 * Mongolian variation selectors, looks like Uniscribe
548 * marks them as non-mark. Some Mongolian fonts without
549 * GDEF rely on this. Another notable character that
550 * this applies to is COMBINING GRAPHEME JOINER. */
551 klass = (_hb_glyph_info_get_general_category (&info[i]) !=
552 HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK ||
553 _hb_glyph_info_is_default_ignorable (&info[i])) ?
554 HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH :
555 HB_OT_LAYOUT_GLYPH_PROPS_MARK;
556 _hb_glyph_info_set_glyph_props (&info[i], klass);
557 }
558 }
559
560 static inline void
561 hb_ot_substitute_default (hb_ot_shape_context_t *c)
562 {
563 hb_buffer_t *buffer = c->buffer;
564
565 hb_ot_shape_initialize_masks (c);
566
567 hb_ot_mirror_chars (c);
568
569 HB_BUFFER_ALLOCATE_VAR (buffer, glyph_index);
570
571 _hb_ot_shape_normalize (c->plan, buffer, c->font);
572
573 hb_ot_shape_setup_masks (c);
574
575 /* This is unfortunate to go here, but necessary... */
576 if (c->fallback_positioning)
577 _hb_ot_shape_fallback_position_recategorize_marks (c->plan, c->font, buffer);
578
579 hb_ot_map_glyphs_fast (buffer);
580
581 HB_BUFFER_DEALLOCATE_VAR (buffer, glyph_index);
582 }
583
584 static inline void
585 hb_ot_substitute_complex (hb_ot_shape_context_t *c)
586 {
587 hb_buffer_t *buffer = c->buffer;
588
589 hb_ot_layout_substitute_start (c->font, buffer);
590
591 if (!hb_ot_layout_has_glyph_classes (c->face))
592 hb_synthesize_glyph_classes (c);
593
594 c->plan->substitute (c->font, buffer);
595
596 return;
597 }
598
599 static inline void
600 hb_ot_substitute (hb_ot_shape_context_t *c)
601 {
602 hb_ot_substitute_default (c);
603
604 _hb_buffer_allocate_gsubgpos_vars (c->buffer);
605
606 hb_ot_substitute_complex (c);
607 }
608
609 /* Position */
610
611 static inline void
612 adjust_mark_offsets (hb_glyph_position_t *pos)
613 {
614 pos->x_offset -= pos->x_advance;
615 pos->y_offset -= pos->y_advance;
616 }
617
618 static inline void
619 zero_mark_width (hb_glyph_position_t *pos)
620 {
621 pos->x_advance = 0;
622 pos->y_advance = 0;
623 }
624
625 static inline void
626 zero_mark_widths_by_gdef (hb_buffer_t *buffer, bool adjust_offsets)
627 {
628 unsigned int count = buffer->len;
629 hb_glyph_info_t *info = buffer->info;
630 for (unsigned int i = 0; i < count; i++)
631 if (_hb_glyph_info_is_mark (&info[i]))
632 {
633 if (adjust_offsets)
634 adjust_mark_offsets (&buffer->pos[i]);
635 zero_mark_width (&buffer->pos[i]);
636 }
637 }
638
639 static inline void
640 hb_ot_position_default (hb_ot_shape_context_t *c)
641 {
642 hb_direction_t direction = c->buffer->props.direction;
643 unsigned int count = c->buffer->len;
644 hb_glyph_info_t *info = c->buffer->info;
645 hb_glyph_position_t *pos = c->buffer->pos;
646
647 if (HB_DIRECTION_IS_HORIZONTAL (direction))
648 {
649 for (unsigned int i = 0; i < count; i++)
650 pos[i].x_advance = c->font->get_glyph_h_advance (info[i].codepoint);
651 /* The nil glyph_h_origin() func returns 0, so no need to apply it. */
652 if (c->font->has_glyph_h_origin_func ())
653 for (unsigned int i = 0; i < count; i++)
654 c->font->subtract_glyph_h_origin (info[i].codepoint,
655 &pos[i].x_offset,
656 &pos[i].y_offset);
657 }
658 else
659 {
660 for (unsigned int i = 0; i < count; i++)
661 {
662 pos[i].y_advance = c->font->get_glyph_v_advance (info[i].codepoint);
663 c->font->subtract_glyph_v_origin (info[i].codepoint,
664 &pos[i].x_offset,
665 &pos[i].y_offset);
666 }
667 }
668 if (c->buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_SPACE_FALLBACK)
669 _hb_ot_shape_fallback_spaces (c->plan, c->font, c->buffer);
670 }
671
672 static inline void
673 hb_ot_position_complex (hb_ot_shape_context_t *c)
674 {
675 hb_ot_layout_position_start (c->font, c->buffer);
676
677 unsigned int count = c->buffer->len;
678
679 /* If the font has no GPOS, AND, no fallback positioning will
680 * happen, AND, direction is forward, then when zeroing mark
681 * widths, we shift the mark with it, such that the mark
682 * is positioned hanging over the previous glyph. When
683 * direction is backward we don't shift and it will end up
684 * hanging over the next glyph after the final reordering.
685 * If fallback positinoing happens or GPOS is present, we don't
686 * care.
687 */
688 bool adjust_offsets_when_zeroing = c->fallback_positioning &&
689 !c->plan->shaper->fallback_position &&
690 HB_DIRECTION_IS_FORWARD (c->buffer->props.direction);
691
692 switch (c->plan->shaper->zero_width_marks)
693 {
694 case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY:
695 zero_mark_widths_by_gdef (c->buffer, adjust_offsets_when_zeroing);
696 break;
697
698 default:
699 case HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE:
700 case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE:
701 break;
702 }
703
704 if (likely (!c->fallback_positioning))
705 {
706 hb_glyph_info_t *info = c->buffer->info;
707 hb_glyph_position_t *pos = c->buffer->pos;
708
709 /* Change glyph origin to what GPOS expects (horizontal), apply GPOS, change it back. */
710
711 /* The nil glyph_h_origin() func returns 0, so no need to apply it. */
712 if (c->font->has_glyph_h_origin_func ())
713 for (unsigned int i = 0; i < count; i++)
714 c->font->add_glyph_h_origin (info[i].codepoint,
715 &pos[i].x_offset,
716 &pos[i].y_offset);
717
718 c->plan->position (c->font, c->buffer);
719
720 /* The nil glyph_h_origin() func returns 0, so no need to apply it. */
721 if (c->font->has_glyph_h_origin_func ())
722 for (unsigned int i = 0; i < count; i++)
723 c->font->subtract_glyph_h_origin (info[i].codepoint,
724 &pos[i].x_offset,
725 &pos[i].y_offset);
726
727 }
728
729 switch (c->plan->shaper->zero_width_marks)
730 {
731 case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE:
732 zero_mark_widths_by_gdef (c->buffer, adjust_offsets_when_zeroing);
733 break;
734
735 default:
736 case HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE:
737 case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY:
738 break;
739 }
740
741 /* Finishing off GPOS has to follow a certain order. */
742 hb_ot_layout_position_finish_advances (c->font, c->buffer);
743 hb_ot_zero_width_default_ignorables (c);
744 hb_ot_layout_position_finish_offsets (c->font, c->buffer);
745 }
746
747 static inline void
748 hb_ot_position (hb_ot_shape_context_t *c)
749 {
750 c->buffer->clear_positions ();
751
752 hb_ot_position_default (c);
753
754 hb_ot_position_complex (c);
755
756 if (c->fallback_positioning && c->plan->shaper->fallback_position)
757 _hb_ot_shape_fallback_position (c->plan, c->font, c->buffer);
758
759 if (HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction))
760 hb_buffer_reverse (c->buffer);
761
762 /* Visual fallback goes here. */
763
764 if (c->fallback_positioning)
765 _hb_ot_shape_fallback_kern (c->plan, c->font, c->buffer);
766
767 _hb_buffer_deallocate_gsubgpos_vars (c->buffer);
768 }
769
770
771 /* Pull it all together! */
772
773 static void
774 hb_ot_shape_internal (hb_ot_shape_context_t *c)
775 {
776 c->buffer->deallocate_var_all ();
777 c->buffer->scratch_flags = HB_BUFFER_SCRATCH_FLAG_DEFAULT;
778 if (likely (!_hb_unsigned_int_mul_overflows (c->buffer->len, HB_BUFFER_MAX_EXPANSION_FACTOR)))
779 {
780 c->buffer->max_len = MAX (c->buffer->len * HB_BUFFER_MAX_EXPANSION_FACTOR,
781 (unsigned) HB_BUFFER_MAX_LEN_MIN);
782 }
783
784 bool disable_otl = c->plan->shaper->disable_otl && c->plan->shaper->disable_otl (c->plan);
785 //c->fallback_substitute = disable_otl || !hb_ot_layout_has_substitution (c->face);
786 c->fallback_positioning = disable_otl || !hb_ot_layout_has_positioning (c->face);
787 c->fallback_glyph_classes = disable_otl || !hb_ot_layout_has_glyph_classes (c->face);
788
789 /* Save the original direction, we use it later. */
790 c->target_direction = c->buffer->props.direction;
791
792 _hb_buffer_allocate_unicode_vars (c->buffer);
793
794 c->buffer->clear_output ();
795
796 hb_set_unicode_props (c->buffer);
797 hb_insert_dotted_circle (c->buffer, c->font);
798 hb_form_clusters (c->buffer);
799
800 hb_ensure_native_direction (c->buffer);
801
802 if (c->plan->shaper->preprocess_text)
803 c->plan->shaper->preprocess_text (c->plan, c->buffer, c->font);
804
805 hb_ot_substitute (c);
806 hb_ot_position (c);
807
808 hb_ot_hide_default_ignorables (c);
809
810 if (c->plan->shaper->postprocess_glyphs)
811 c->plan->shaper->postprocess_glyphs (c->plan, c->buffer, c->font);
812
813 _hb_buffer_deallocate_unicode_vars (c->buffer);
814
815 c->buffer->props.direction = c->target_direction;
816
817 c->buffer->max_len = HB_BUFFER_MAX_LEN_DEFAULT;
818 c->buffer->deallocate_var_all ();
819 }
820
821
822 hb_bool_t
823 _hb_ot_shape (hb_shape_plan_t *shape_plan,
824 hb_font_t *font,
825 hb_buffer_t *buffer,
826 const hb_feature_t *features,
827 unsigned int num_features)
828 {
829 hb_ot_shape_context_t c = {HB_SHAPER_DATA_GET (shape_plan), font, font->face, buffer, features, num_features};
830 hb_ot_shape_internal (&c);
831
832 return true;
833 }
834
835
836 /**
837 * hb_ot_shape_plan_collect_lookups:
838 *
839 * Since: 0.9.7
840 **/
841 void
842 hb_ot_shape_plan_collect_lookups (hb_shape_plan_t *shape_plan,
843 hb_tag_t table_tag,
844 hb_set_t *lookup_indexes /* OUT */)
845 {
846 /* XXX Does the first part always succeed? */
847 HB_SHAPER_DATA_GET (shape_plan)->collect_lookups (table_tag, lookup_indexes);
848 }
849
850
851 /* TODO Move this to hb-ot-shape-normalize, make it do decompose, and make it public. */
852 static void
853 add_char (hb_font_t *font,
854 hb_unicode_funcs_t *unicode,
855 hb_bool_t mirror,
856 hb_codepoint_t u,
857 hb_set_t *glyphs)
858 {
859 hb_codepoint_t glyph;
860 if (font->get_nominal_glyph (u, &glyph))
861 glyphs->add (glyph);
862 if (mirror)
863 {
864 hb_codepoint_t m = unicode->mirroring (u);
865 if (m != u && font->get_nominal_glyph (m, &glyph))
866 glyphs->add (glyph);
867 }
868 }
869
870
871 /**
872 * hb_ot_shape_glyphs_closure:
873 *
874 * Since: 0.9.2
875 **/
876 void
877 hb_ot_shape_glyphs_closure (hb_font_t *font,
878 hb_buffer_t *buffer,
879 const hb_feature_t *features,
880 unsigned int num_features,
881 hb_set_t *glyphs)
882 {
883 hb_ot_shape_plan_t plan;
884
885 const char *shapers[] = {"ot", NULL};
886 hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached (font->face, &buffer->props,
887 features, num_features, shapers);
888
889 bool mirror = hb_script_get_horizontal_direction (buffer->props.script) == HB_DIRECTION_RTL;
890
891 unsigned int count = buffer->len;
892 hb_glyph_info_t *info = buffer->info;
893 for (unsigned int i = 0; i < count; i++)
894 add_char (font, buffer->unicode, mirror, info[i].codepoint, glyphs);
895
896 hb_set_t lookups;
897 lookups.init ();
898 hb_ot_shape_plan_collect_lookups (shape_plan, HB_OT_TAG_GSUB, &lookups);
899
900 /* And find transitive closure. */
901 hb_set_t copy;
902 copy.init ();
903 do {
904 copy.set (glyphs);
905 for (hb_codepoint_t lookup_index = -1; hb_set_next (&lookups, &lookup_index);)
906 hb_ot_layout_lookup_substitute_closure (font->face, lookup_index, glyphs);
907 } while (!copy.is_equal (glyphs));
908
909 hb_shape_plan_destroy (shape_plan);
910 }