1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 // This file is available under and governed by the GNU General Public
26 // License version 2 only, as published by the Free Software Foundation.
27 // However, the following notice accompanied the original version of this
28 // file:
29 //
30 /*
31 * Copyright © 2011,2012 Google, Inc.
32 *
33 * This is part of HarfBuzz, a text shaping library.
34 *
35 * Permission is hereby granted, without written agreement and without
36 * license or royalty fees, to use, copy, modify, and distribute this
37 * software and its documentation for any purpose, provided that the
38 * above copyright notice and the following two paragraphs appear in
39 * all copies of this software.
40 *
41 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
42 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
43 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
44 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
45 * DAMAGE.
46 *
47 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
48 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
49 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
50 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
51 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
52 *
53 * Google Author(s): Behdad Esfahbod
54 */
55
56 #include "hb-ot-shape-fallback-private.hh"
57 #include "hb-ot-layout-gsubgpos-private.hh"
58
59 static unsigned int
60 recategorize_combining_class (hb_codepoint_t u,
61 unsigned int klass)
62 {
63 if (klass >= 200)
64 return klass;
65
66 /* Thai / Lao need some per-character work. */
67 if ((u & ~0xFF) == 0x0E00u)
68 {
69 if (unlikely (klass == 0))
70 {
71 switch (u)
72 {
73 case 0x0E31u:
74 case 0x0E34u:
75 case 0x0E35u:
76 case 0x0E36u:
77 case 0x0E37u:
78 case 0x0E47u:
79 case 0x0E4Cu:
80 case 0x0E4Du:
81 case 0x0E4Eu:
82 klass = HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
83 break;
84
85 case 0x0EB1u:
86 case 0x0EB4u:
87 case 0x0EB5u:
88 case 0x0EB6u:
89 case 0x0EB7u:
90 case 0x0EBBu:
91 case 0x0ECCu:
92 case 0x0ECDu:
93 klass = HB_UNICODE_COMBINING_CLASS_ABOVE;
94 break;
95
96 case 0x0EBCu:
97 klass = HB_UNICODE_COMBINING_CLASS_BELOW;
98 break;
99 }
100 } else {
101 /* Thai virama is below-right */
102 if (u == 0x0E3Au)
103 klass = HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT;
104 }
105 }
106
107 switch (klass)
108 {
109
110 /* Hebrew */
111
112 case HB_MODIFIED_COMBINING_CLASS_CCC10: /* sheva */
113 case HB_MODIFIED_COMBINING_CLASS_CCC11: /* hataf segol */
114 case HB_MODIFIED_COMBINING_CLASS_CCC12: /* hataf patah */
115 case HB_MODIFIED_COMBINING_CLASS_CCC13: /* hataf qamats */
116 case HB_MODIFIED_COMBINING_CLASS_CCC14: /* hiriq */
117 case HB_MODIFIED_COMBINING_CLASS_CCC15: /* tsere */
118 case HB_MODIFIED_COMBINING_CLASS_CCC16: /* segol */
119 case HB_MODIFIED_COMBINING_CLASS_CCC17: /* patah */
120 case HB_MODIFIED_COMBINING_CLASS_CCC18: /* qamats */
121 case HB_MODIFIED_COMBINING_CLASS_CCC20: /* qubuts */
122 case HB_MODIFIED_COMBINING_CLASS_CCC22: /* meteg */
123 return HB_UNICODE_COMBINING_CLASS_BELOW;
124
125 case HB_MODIFIED_COMBINING_CLASS_CCC23: /* rafe */
126 return HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE;
127
128 case HB_MODIFIED_COMBINING_CLASS_CCC24: /* shin dot */
129 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
130
131 case HB_MODIFIED_COMBINING_CLASS_CCC25: /* sin dot */
132 case HB_MODIFIED_COMBINING_CLASS_CCC19: /* holam */
133 return HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT;
134
135 case HB_MODIFIED_COMBINING_CLASS_CCC26: /* point varika */
136 return HB_UNICODE_COMBINING_CLASS_ABOVE;
137
138 case HB_MODIFIED_COMBINING_CLASS_CCC21: /* dagesh */
139 break;
140
141
142 /* Arabic and Syriac */
143
144 case HB_MODIFIED_COMBINING_CLASS_CCC27: /* fathatan */
145 case HB_MODIFIED_COMBINING_CLASS_CCC28: /* dammatan */
146 case HB_MODIFIED_COMBINING_CLASS_CCC30: /* fatha */
147 case HB_MODIFIED_COMBINING_CLASS_CCC31: /* damma */
148 case HB_MODIFIED_COMBINING_CLASS_CCC33: /* shadda */
149 case HB_MODIFIED_COMBINING_CLASS_CCC34: /* sukun */
150 case HB_MODIFIED_COMBINING_CLASS_CCC35: /* superscript alef */
151 case HB_MODIFIED_COMBINING_CLASS_CCC36: /* superscript alaph */
152 return HB_UNICODE_COMBINING_CLASS_ABOVE;
153
154 case HB_MODIFIED_COMBINING_CLASS_CCC29: /* kasratan */
155 case HB_MODIFIED_COMBINING_CLASS_CCC32: /* kasra */
156 return HB_UNICODE_COMBINING_CLASS_BELOW;
157
158
159 /* Thai */
160
161 case HB_MODIFIED_COMBINING_CLASS_CCC103: /* sara u / sara uu */
162 return HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT;
163
164 case HB_MODIFIED_COMBINING_CLASS_CCC107: /* mai */
165 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
166
167
168 /* Lao */
169
170 case HB_MODIFIED_COMBINING_CLASS_CCC118: /* sign u / sign uu */
171 return HB_UNICODE_COMBINING_CLASS_BELOW;
172
173 case HB_MODIFIED_COMBINING_CLASS_CCC122: /* mai */
174 return HB_UNICODE_COMBINING_CLASS_ABOVE;
175
176
177 /* Tibetan */
178
179 case HB_MODIFIED_COMBINING_CLASS_CCC129: /* sign aa */
180 return HB_UNICODE_COMBINING_CLASS_BELOW;
181
182 case HB_MODIFIED_COMBINING_CLASS_CCC130: /* sign i*/
183 return HB_UNICODE_COMBINING_CLASS_ABOVE;
184
185 case HB_MODIFIED_COMBINING_CLASS_CCC132: /* sign u */
186 return HB_UNICODE_COMBINING_CLASS_BELOW;
187
188 }
189
190 return klass;
191 }
192
193 void
194 _hb_ot_shape_fallback_position_recategorize_marks (const hb_ot_shape_plan_t *plan HB_UNUSED,
195 hb_font_t *font HB_UNUSED,
196 hb_buffer_t *buffer)
197 {
198 unsigned int count = buffer->len;
199 hb_glyph_info_t *info = buffer->info;
200 for (unsigned int i = 0; i < count; i++)
201 if (_hb_glyph_info_get_general_category (&info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) {
202 unsigned int combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]);
203 combining_class = recategorize_combining_class (info[i].codepoint, combining_class);
204 _hb_glyph_info_set_modified_combining_class (&info[i], combining_class);
205 }
206 }
207
208
209 static void
210 zero_mark_advances (hb_buffer_t *buffer,
211 unsigned int start,
212 unsigned int end)
213 {
214 hb_glyph_info_t *info = buffer->info;
215 for (unsigned int i = start; i < end; i++)
216 if (_hb_glyph_info_get_general_category (&info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)
217 {
218 buffer->pos[i].x_advance = 0;
219 buffer->pos[i].y_advance = 0;
220 }
221 }
222
223 static inline void
224 position_mark (const hb_ot_shape_plan_t *plan,
225 hb_font_t *font,
226 hb_buffer_t *buffer,
227 hb_glyph_extents_t &base_extents,
228 unsigned int i,
229 unsigned int combining_class)
230 {
231 hb_glyph_extents_t mark_extents;
232 if (!font->get_glyph_extents (buffer->info[i].codepoint,
233 &mark_extents))
234 return;
235
236 hb_position_t y_gap = font->y_scale / 16;
237
238 hb_glyph_position_t &pos = buffer->pos[i];
239 pos.x_offset = pos.y_offset = 0;
240
241
242 /* We dont position LEFT and RIGHT marks. */
243
244 /* X positioning */
245 switch (combining_class)
246 {
247 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
248 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
249 if (buffer->props.direction == HB_DIRECTION_LTR) {
250 pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing;
251 break;
252 } else if (buffer->props.direction == HB_DIRECTION_RTL) {
253 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing;
254 break;
255 }
256 /* Fall through */
257
258 default:
259 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
260 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
261 case HB_UNICODE_COMBINING_CLASS_BELOW:
262 case HB_UNICODE_COMBINING_CLASS_ABOVE:
263 /* Center align. */
264 pos.x_offset += base_extents.x_bearing + (base_extents.width - mark_extents.width) / 2 - mark_extents.x_bearing;
265 break;
266
267 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
268 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
269 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
270 /* Left align. */
271 pos.x_offset += base_extents.x_bearing - mark_extents.x_bearing;
272 break;
273
274 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
275 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
276 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
277 /* Right align. */
278 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width - mark_extents.x_bearing;
279 break;
280 }
281
282 /* Y positioning */
283 switch (combining_class)
284 {
285 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
286 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
287 case HB_UNICODE_COMBINING_CLASS_BELOW:
288 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
289 /* Add gap, fall-through. */
290 base_extents.height -= y_gap;
291
292 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
293 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
294 pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing;
295 /* Never shift up "below" marks. */
296 if ((y_gap > 0) == (pos.y_offset > 0))
297 {
298 base_extents.height -= pos.y_offset;
299 pos.y_offset = 0;
300 }
301 base_extents.height += mark_extents.height;
302 break;
303
304 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
305 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
306 case HB_UNICODE_COMBINING_CLASS_ABOVE:
307 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
308 /* Add gap, fall-through. */
309 base_extents.y_bearing += y_gap;
310 base_extents.height -= y_gap;
311
312 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
313 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
314 pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height);
315 /* Don't shift down "above" marks too much. */
316 if ((y_gap > 0) != (pos.y_offset > 0))
317 {
318 unsigned int correction = -pos.y_offset / 2;
319 base_extents.y_bearing += correction;
320 base_extents.height -= correction;
321 pos.y_offset += correction;
322 }
323 base_extents.y_bearing -= mark_extents.height;
324 base_extents.height += mark_extents.height;
325 break;
326 }
327 }
328
329 static inline void
330 position_around_base (const hb_ot_shape_plan_t *plan,
331 hb_font_t *font,
332 hb_buffer_t *buffer,
333 unsigned int base,
334 unsigned int end)
335 {
336 hb_direction_t horiz_dir = HB_DIRECTION_INVALID;
337 hb_glyph_extents_t base_extents;
338 if (!font->get_glyph_extents (buffer->info[base].codepoint,
339 &base_extents))
340 {
341 /* If extents don't work, zero marks and go home. */
342 zero_mark_advances (buffer, base + 1, end);
343 return;
344 }
345 base_extents.x_bearing += buffer->pos[base].x_offset;
346 base_extents.y_bearing += buffer->pos[base].y_offset;
347
348 unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]);
349 unsigned int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]);
350
351 hb_position_t x_offset = 0, y_offset = 0;
352 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
353 x_offset -= buffer->pos[base].x_advance;
354 y_offset -= buffer->pos[base].y_advance;
355 }
356
357 hb_glyph_extents_t component_extents = base_extents;
358 unsigned int last_lig_component = (unsigned int) -1;
359 unsigned int last_combining_class = 255;
360 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */
361 hb_glyph_info_t *info = buffer->info;
362 for (unsigned int i = base + 1; i < end; i++)
363 if (_hb_glyph_info_get_modified_combining_class (&info[i]))
364 {
365 if (num_lig_components > 1) {
366 unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&info[i]);
367 unsigned int this_lig_component = _hb_glyph_info_get_lig_comp (&info[i]) - 1;
368 /* Conditions for attaching to the last component. */
369 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components)
370 this_lig_component = num_lig_components - 1;
371 if (last_lig_component != this_lig_component)
372 {
373 last_lig_component = this_lig_component;
374 last_combining_class = 255;
375 component_extents = base_extents;
376 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) {
377 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction))
378 horiz_dir = plan->props.direction;
379 else
380 horiz_dir = hb_script_get_horizontal_direction (plan->props.script);
381 }
382 if (horiz_dir == HB_DIRECTION_LTR)
383 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components;
384 else
385 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components;
386 component_extents.width /= num_lig_components;
387 }
388 }
389
390 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]);
391 if (last_combining_class != this_combining_class)
392 {
393 last_combining_class = this_combining_class;
394 cluster_extents = component_extents;
395 }
396
397 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class);
398
399 buffer->pos[i].x_advance = 0;
400 buffer->pos[i].y_advance = 0;
401 buffer->pos[i].x_offset += x_offset;
402 buffer->pos[i].y_offset += y_offset;
403
404 } else {
405 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
406 x_offset -= buffer->pos[i].x_advance;
407 y_offset -= buffer->pos[i].y_advance;
408 } else {
409 x_offset += buffer->pos[i].x_advance;
410 y_offset += buffer->pos[i].y_advance;
411 }
412 }
413 }
414
415 static inline void
416 position_cluster (const hb_ot_shape_plan_t *plan,
417 hb_font_t *font,
418 hb_buffer_t *buffer,
419 unsigned int start,
420 unsigned int end)
421 {
422 if (end - start < 2)
423 return;
424
425 /* Find the base glyph */
426 hb_glyph_info_t *info = buffer->info;
427 for (unsigned int i = start; i < end; i++)
428 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])))
429 {
430 /* Find mark glyphs */
431 unsigned int j;
432 for (j = i + 1; j < end; j++)
433 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[j])))
434 break;
435
436 position_around_base (plan, font, buffer, i, j);
437
438 i = j - 1;
439 }
440 }
441
442 void
443 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan,
444 hb_font_t *font,
445 hb_buffer_t *buffer)
446 {
447 _hb_buffer_assert_gsubgpos_vars (buffer);
448
449 unsigned int start = 0;
450 unsigned int count = buffer->len;
451 hb_glyph_info_t *info = buffer->info;
452 for (unsigned int i = 1; i < count; i++)
453 if (likely (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])))) {
454 position_cluster (plan, font, buffer, start, i);
455 start = i;
456 }
457 position_cluster (plan, font, buffer, start, count);
458 }
459
460
461 /* Performs old-style TrueType kerning. */
462 void
463 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
464 hb_font_t *font,
465 hb_buffer_t *buffer)
466 {
467 if (!plan->has_kern) return;
468
469 OT::hb_apply_context_t c (1, font, buffer);
470 c.set_lookup_mask (plan->kern_mask);
471 c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
472 OT::hb_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input;
473 skippy_iter.init (&c);
474
475 unsigned int count = buffer->len;
476 hb_glyph_info_t *info = buffer->info;
477 hb_glyph_position_t *pos = buffer->pos;
478 for (unsigned int idx = 0; idx < count;)
479 {
480 skippy_iter.reset (idx, 1);
481 if (!skippy_iter.next ())
482 {
483 idx++;
484 continue;
485 }
486
487 hb_position_t x_kern, y_kern;
488 font->get_glyph_kerning_for_direction (info[idx].codepoint,
489 info[skippy_iter.idx].codepoint,
490 buffer->props.direction,
491 &x_kern, &y_kern);
492
493 if (x_kern)
494 {
495 hb_position_t kern1 = x_kern >> 1;
496 hb_position_t kern2 = x_kern - kern1;
497 pos[idx].x_advance += kern1;
498 pos[skippy_iter.idx].x_advance += kern2;
499 pos[skippy_iter.idx].x_offset += kern2;
500 }
501
502 if (y_kern)
503 {
504 hb_position_t kern1 = y_kern >> 1;
505 hb_position_t kern2 = y_kern - kern1;
506 pos[idx].y_advance += kern1;
507 pos[skippy_iter.idx].y_advance += kern2;
508 pos[skippy_iter.idx].y_offset += kern2;
509 }
510
511 idx = skippy_iter.idx;
512 }
513 }