1 /*
2 * Copyright © 2011,2012 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
25 */
26
27 #include "hb-ot-shape-fallback-private.hh"
28 #include "hb-ot-layout-gsubgpos-private.hh"
29
30 static unsigned int
recategorize_combining_class(hb_codepoint_t u,unsigned int klass)31 recategorize_combining_class (hb_codepoint_t u,
32 unsigned int klass)
33 {
34 if (klass >= 200)
35 return klass;
36
37 /* Thai / Lao need some per-character work. */
38 if ((u & ~0xFF) == 0x0E00)
39 {
40 if (unlikely (klass == 0))
41 {
42 switch (u)
43 {
44 case 0x0E31:
45 case 0x0E34:
46 case 0x0E35:
47 case 0x0E36:
48 case 0x0E37:
49 case 0x0E47:
50 case 0x0E4C:
51 case 0x0E4D:
52 case 0x0E4E:
53 klass = HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
54 break;
55
56 case 0x0EB1:
57 case 0x0EB4:
58 case 0x0EB5:
59 case 0x0EB6:
60 case 0x0EB7:
61 case 0x0EBB:
62 case 0x0ECC:
63 case 0x0ECD:
64 klass = HB_UNICODE_COMBINING_CLASS_ABOVE;
65 break;
66
67 case 0x0EBC:
68 klass = HB_UNICODE_COMBINING_CLASS_BELOW;
69 break;
70 }
71 } else {
72 /* Thai virama is below-right */
73 if (u == 0x0E3A)
74 klass = HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT;
75 }
76 }
77
78 switch (klass)
79 {
80
81 /* Hebrew */
82
83 case HB_MODIFIED_COMBINING_CLASS_CCC10: /* sheva */
84 case HB_MODIFIED_COMBINING_CLASS_CCC11: /* hataf segol */
85 case HB_MODIFIED_COMBINING_CLASS_CCC12: /* hataf patah */
86 case HB_MODIFIED_COMBINING_CLASS_CCC13: /* hataf qamats */
87 case HB_MODIFIED_COMBINING_CLASS_CCC14: /* hiriq */
88 case HB_MODIFIED_COMBINING_CLASS_CCC15: /* tsere */
89 case HB_MODIFIED_COMBINING_CLASS_CCC16: /* segol */
90 case HB_MODIFIED_COMBINING_CLASS_CCC17: /* patah */
91 case HB_MODIFIED_COMBINING_CLASS_CCC18: /* qamats */
92 case HB_MODIFIED_COMBINING_CLASS_CCC20: /* qubuts */
93 case HB_MODIFIED_COMBINING_CLASS_CCC22: /* meteg */
94 return HB_UNICODE_COMBINING_CLASS_BELOW;
95
96 case HB_MODIFIED_COMBINING_CLASS_CCC23: /* rafe */
97 return HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE;
98
99 case HB_MODIFIED_COMBINING_CLASS_CCC24: /* shin dot */
100 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
101
102 case HB_MODIFIED_COMBINING_CLASS_CCC25: /* sin dot */
103 case HB_MODIFIED_COMBINING_CLASS_CCC19: /* holam */
104 return HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT;
105
106 case HB_MODIFIED_COMBINING_CLASS_CCC26: /* point varika */
107 return HB_UNICODE_COMBINING_CLASS_ABOVE;
108
109 case HB_MODIFIED_COMBINING_CLASS_CCC21: /* dagesh */
110 break;
111
112
113 /* Arabic and Syriac */
114
115 case HB_MODIFIED_COMBINING_CLASS_CCC27: /* fathatan */
116 case HB_MODIFIED_COMBINING_CLASS_CCC28: /* dammatan */
117 case HB_MODIFIED_COMBINING_CLASS_CCC30: /* fatha */
118 case HB_MODIFIED_COMBINING_CLASS_CCC31: /* damma */
119 case HB_MODIFIED_COMBINING_CLASS_CCC33: /* shadda */
120 case HB_MODIFIED_COMBINING_CLASS_CCC34: /* sukun */
121 case HB_MODIFIED_COMBINING_CLASS_CCC35: /* superscript alef */
122 case HB_MODIFIED_COMBINING_CLASS_CCC36: /* superscript alaph */
123 return HB_UNICODE_COMBINING_CLASS_ABOVE;
124
125 case HB_MODIFIED_COMBINING_CLASS_CCC29: /* kasratan */
126 case HB_MODIFIED_COMBINING_CLASS_CCC32: /* kasra */
127 return HB_UNICODE_COMBINING_CLASS_BELOW;
128
129
130 /* Thai */
131
132 case HB_MODIFIED_COMBINING_CLASS_CCC103: /* sara u / sara uu */
133 return HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT;
134
135 case HB_MODIFIED_COMBINING_CLASS_CCC107: /* mai */
136 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
137
138
139 /* Lao */
140
141 case HB_MODIFIED_COMBINING_CLASS_CCC118: /* sign u / sign uu */
142 return HB_UNICODE_COMBINING_CLASS_BELOW;
143
144 case HB_MODIFIED_COMBINING_CLASS_CCC122: /* mai */
145 return HB_UNICODE_COMBINING_CLASS_ABOVE;
146
147
148 /* Tibetan */
149
150 case HB_MODIFIED_COMBINING_CLASS_CCC129: /* sign aa */
151 return HB_UNICODE_COMBINING_CLASS_BELOW;
152
153 case HB_MODIFIED_COMBINING_CLASS_CCC130: /* sign i*/
154 return HB_UNICODE_COMBINING_CLASS_ABOVE;
155
156 case HB_MODIFIED_COMBINING_CLASS_CCC132: /* sign u */
157 return HB_UNICODE_COMBINING_CLASS_BELOW;
158
159 }
160
161 return klass;
162 }
163
164 void
_hb_ot_shape_fallback_position_recategorize_marks(const hb_ot_shape_plan_t * plan HB_UNUSED,hb_font_t * font HB_UNUSED,hb_buffer_t * buffer)165 _hb_ot_shape_fallback_position_recategorize_marks (const hb_ot_shape_plan_t *plan HB_UNUSED,
166 hb_font_t *font HB_UNUSED,
167 hb_buffer_t *buffer)
168 {
169 unsigned int count = buffer->len;
170 for (unsigned int i = 0; i < count; i++)
171 if (_hb_glyph_info_get_general_category (&buffer->info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) {
172 unsigned int combining_class = _hb_glyph_info_get_modified_combining_class (&buffer->info[i]);
173 combining_class = recategorize_combining_class (buffer->info[i].codepoint, combining_class);
174 _hb_glyph_info_set_modified_combining_class (&buffer->info[i], combining_class);
175 }
176 }
177
178
179 static void
zero_mark_advances(hb_buffer_t * buffer,unsigned int start,unsigned int end)180 zero_mark_advances (hb_buffer_t *buffer,
181 unsigned int start,
182 unsigned int end)
183 {
184 for (unsigned int i = start; i < end; i++)
185 if (_hb_glyph_info_get_general_category (&buffer->info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)
186 {
187 buffer->pos[i].x_advance = 0;
188 buffer->pos[i].y_advance = 0;
189 }
190 }
191
192 static inline void
position_mark(const hb_ot_shape_plan_t * plan,hb_font_t * font,hb_buffer_t * buffer,hb_glyph_extents_t & base_extents,unsigned int i,unsigned int combining_class)193 position_mark (const hb_ot_shape_plan_t *plan,
194 hb_font_t *font,
195 hb_buffer_t *buffer,
196 hb_glyph_extents_t &base_extents,
197 unsigned int i,
198 unsigned int combining_class)
199 {
200 hb_glyph_extents_t mark_extents;
201 if (!font->get_glyph_extents (buffer->info[i].codepoint,
202 &mark_extents))
203 return;
204
205 hb_position_t y_gap = font->y_scale / 16;
206
207 hb_glyph_position_t &pos = buffer->pos[i];
208 pos.x_offset = pos.y_offset = 0;
209
210
211 /* We dont position LEFT and RIGHT marks. */
212
213 /* X positioning */
214 switch (combining_class)
215 {
216 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
217 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
218 if (buffer->props.direction == HB_DIRECTION_LTR) {
219 pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing;
220 break;
221 } else if (buffer->props.direction == HB_DIRECTION_RTL) {
222 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing;
223 break;
224 }
225 /* Fall through */
226
227 default:
228 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
229 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
230 case HB_UNICODE_COMBINING_CLASS_BELOW:
231 case HB_UNICODE_COMBINING_CLASS_ABOVE:
232 /* Center align. */
233 pos.x_offset += base_extents.x_bearing + (base_extents.width - mark_extents.width) / 2 - mark_extents.x_bearing;
234 break;
235
236 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
237 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
238 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
239 /* Left align. */
240 pos.x_offset += base_extents.x_bearing - mark_extents.x_bearing;
241 break;
242
243 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
244 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
245 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
246 /* Right align. */
247 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width - mark_extents.x_bearing;
248 break;
249 }
250
251 /* Y positioning */
252 switch (combining_class)
253 {
254 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
255 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
256 case HB_UNICODE_COMBINING_CLASS_BELOW:
257 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
258 /* Add gap, fall-through. */
259 base_extents.height -= y_gap;
260
261 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
262 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
263 pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing;
264 /* Never shift up "below" marks. */
265 if ((y_gap > 0) == (pos.y_offset > 0))
266 {
267 base_extents.height -= pos.y_offset;
268 pos.y_offset = 0;
269 }
270 base_extents.height += mark_extents.height;
271 break;
272
273 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
274 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
275 case HB_UNICODE_COMBINING_CLASS_ABOVE:
276 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
277 /* Add gap, fall-through. */
278 base_extents.y_bearing += y_gap;
279 base_extents.height -= y_gap;
280
281 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
282 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
283 pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height);
284 /* Don't shift down "above" marks too much. */
285 if ((y_gap > 0) != (pos.y_offset > 0))
286 {
287 unsigned int correction = -pos.y_offset / 2;
288 base_extents.y_bearing += correction;
289 base_extents.height -= correction;
290 pos.y_offset += correction;
291 }
292 base_extents.y_bearing -= mark_extents.height;
293 base_extents.height += mark_extents.height;
294 break;
295 }
296 }
297
298 static inline void
position_around_base(const hb_ot_shape_plan_t * plan,hb_font_t * font,hb_buffer_t * buffer,unsigned int base,unsigned int end)299 position_around_base (const hb_ot_shape_plan_t *plan,
300 hb_font_t *font,
301 hb_buffer_t *buffer,
302 unsigned int base,
303 unsigned int end)
304 {
305 hb_direction_t horiz_dir = HB_DIRECTION_INVALID;
306 hb_glyph_extents_t base_extents;
307 if (!font->get_glyph_extents (buffer->info[base].codepoint,
308 &base_extents))
309 {
310 /* If extents don't work, zero marks and go home. */
311 zero_mark_advances (buffer, base + 1, end);
312 return;
313 }
314 base_extents.x_bearing += buffer->pos[base].x_offset;
315 base_extents.y_bearing += buffer->pos[base].y_offset;
316
317 unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]);
318 unsigned int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]);
319
320 hb_position_t x_offset = 0, y_offset = 0;
321 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
322 x_offset -= buffer->pos[base].x_advance;
323 y_offset -= buffer->pos[base].y_advance;
324 }
325
326 hb_glyph_extents_t component_extents = base_extents;
327 unsigned int last_lig_component = (unsigned int) -1;
328 unsigned int last_combining_class = 255;
329 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */
330 for (unsigned int i = base + 1; i < end; i++)
331 if (_hb_glyph_info_get_modified_combining_class (&buffer->info[i]))
332 {
333 if (num_lig_components > 1) {
334 unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&buffer->info[i]);
335 unsigned int this_lig_component = _hb_glyph_info_get_lig_comp (&buffer->info[i]) - 1;
336 /* Conditions for attaching to the last component. */
337 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components)
338 this_lig_component = num_lig_components - 1;
339 if (last_lig_component != this_lig_component)
340 {
341 last_lig_component = this_lig_component;
342 last_combining_class = 255;
343 component_extents = base_extents;
344 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) {
345 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction))
346 horiz_dir = plan->props.direction;
347 else
348 horiz_dir = hb_script_get_horizontal_direction (plan->props.script);
349 }
350 if (horiz_dir == HB_DIRECTION_LTR)
351 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components;
352 else
353 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components;
354 component_extents.width /= num_lig_components;
355 }
356 }
357
358 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&buffer->info[i]);
359 if (last_combining_class != this_combining_class)
360 {
361 last_combining_class = this_combining_class;
362 cluster_extents = component_extents;
363 }
364
365 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class);
366
367 buffer->pos[i].x_advance = 0;
368 buffer->pos[i].y_advance = 0;
369 buffer->pos[i].x_offset += x_offset;
370 buffer->pos[i].y_offset += y_offset;
371
372 } else {
373 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
374 x_offset -= buffer->pos[i].x_advance;
375 y_offset -= buffer->pos[i].y_advance;
376 } else {
377 x_offset += buffer->pos[i].x_advance;
378 y_offset += buffer->pos[i].y_advance;
379 }
380 }
381 }
382
383 static inline void
position_cluster(const hb_ot_shape_plan_t * plan,hb_font_t * font,hb_buffer_t * buffer,unsigned int start,unsigned int end)384 position_cluster (const hb_ot_shape_plan_t *plan,
385 hb_font_t *font,
386 hb_buffer_t *buffer,
387 unsigned int start,
388 unsigned int end)
389 {
390 if (end - start < 2)
391 return;
392
393 /* Find the base glyph */
394 for (unsigned int i = start; i < end; i++)
395 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->info[i])))
396 {
397 /* Find mark glyphs */
398 unsigned int j;
399 for (j = i + 1; j < end; j++)
400 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->info[j])))
401 break;
402
403 position_around_base (plan, font, buffer, i, j);
404
405 i = j - 1;
406 }
407 }
408
409 void
_hb_ot_shape_fallback_position(const hb_ot_shape_plan_t * plan,hb_font_t * font,hb_buffer_t * buffer)410 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan,
411 hb_font_t *font,
412 hb_buffer_t *buffer)
413 {
414 unsigned int start = 0;
415 unsigned int last_cluster = buffer->info[0].cluster;
416 unsigned int count = buffer->len;
417 for (unsigned int i = 1; i < count; i++)
418 if (buffer->info[i].cluster != last_cluster) {
419 position_cluster (plan, font, buffer, start, i);
420 start = i;
421 last_cluster = buffer->info[i].cluster;
422 }
423 position_cluster (plan, font, buffer, start, count);
424 }
425
426
427 /* Performs old-style TrueType kerning. */
428 void
_hb_ot_shape_fallback_kern(const hb_ot_shape_plan_t * plan,hb_font_t * font,hb_buffer_t * buffer)429 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
430 hb_font_t *font,
431 hb_buffer_t *buffer)
432 {
433 hb_mask_t kern_mask = plan->map.get_1_mask (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction) ?
434 HB_TAG ('k','e','r','n') : HB_TAG ('v','k','r','n'));
435 if (!kern_mask) return;
436
437 unsigned int count = buffer->len;
438
439 OT::hb_apply_context_t c (1, font, buffer);
440 c.set_lookup_mask (kern_mask);
441 c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
442
443 hb_glyph_info_t *info = buffer->info;
444 hb_glyph_position_t *pos = buffer->pos;
445
446 for (unsigned int idx = 0; idx < count;)
447 {
448 OT::hb_apply_context_t::skipping_forward_iterator_t skippy_iter (&c, idx, 1);
449 if (!skippy_iter.next ())
450 {
451 idx++;
452 continue;
453 }
454
455 hb_position_t x_kern, y_kern;
456 font->get_glyph_kerning_for_direction (info[idx].codepoint,
457 info[skippy_iter.idx].codepoint,
458 buffer->props.direction,
459 &x_kern, &y_kern);
460
461 if (x_kern)
462 {
463 hb_position_t kern1 = x_kern >> 1;
464 hb_position_t kern2 = x_kern - kern1;
465 pos[idx].x_advance += kern1;
466 pos[skippy_iter.idx].x_advance += kern2;
467 pos[skippy_iter.idx].x_offset += kern2;
468 }
469
470 if (y_kern)
471 {
472 hb_position_t kern1 = y_kern >> 1;
473 hb_position_t kern2 = y_kern - kern1;
474 pos[idx].y_advance += kern1;
475 pos[skippy_iter.idx].y_advance += kern2;
476 pos[skippy_iter.idx].y_offset += kern2;
477 }
478
479 idx = skippy_iter.idx;
480 }
481 }
482