2 * Copyright © 2011,2012 Google, Inc.
4 * This is part of HarfBuzz, a text shaping library.
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.
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
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.
24 * Google Author(s): Behdad Esfahbod
27 #include "hb-ot-shape-fallback-private.hh"
28 #include "hb-ot-layout-gsubgpos-private.hh"
31 recategorize_combining_class (hb_codepoint_t u,
37 /* Thai / Lao need some per-character work. */
38 if ((u & ~0xFF) == 0x0E00u)
40 if (unlikely (klass == 0))
53 klass = HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
64 klass = HB_UNICODE_COMBINING_CLASS_ABOVE;
68 klass = HB_UNICODE_COMBINING_CLASS_BELOW;
72 /* Thai virama is below-right */
74 klass = HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT;
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;
96 case HB_MODIFIED_COMBINING_CLASS_CCC23: /* rafe */
97 return HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE;
99 case HB_MODIFIED_COMBINING_CLASS_CCC24: /* shin dot */
100 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
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;
106 case HB_MODIFIED_COMBINING_CLASS_CCC26: /* point varika */
107 return HB_UNICODE_COMBINING_CLASS_ABOVE;
109 case HB_MODIFIED_COMBINING_CLASS_CCC21: /* dagesh */
113 /* Arabic and Syriac */
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;
125 case HB_MODIFIED_COMBINING_CLASS_CCC29: /* kasratan */
126 case HB_MODIFIED_COMBINING_CLASS_CCC32: /* kasra */
127 return HB_UNICODE_COMBINING_CLASS_BELOW;
132 case HB_MODIFIED_COMBINING_CLASS_CCC103: /* sara u / sara uu */
133 return HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT;
135 case HB_MODIFIED_COMBINING_CLASS_CCC107: /* mai */
136 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT;
141 case HB_MODIFIED_COMBINING_CLASS_CCC118: /* sign u / sign uu */
142 return HB_UNICODE_COMBINING_CLASS_BELOW;
144 case HB_MODIFIED_COMBINING_CLASS_CCC122: /* mai */
145 return HB_UNICODE_COMBINING_CLASS_ABOVE;
150 case HB_MODIFIED_COMBINING_CLASS_CCC129: /* sign aa */
151 return HB_UNICODE_COMBINING_CLASS_BELOW;
153 case HB_MODIFIED_COMBINING_CLASS_CCC130: /* sign i*/
154 return HB_UNICODE_COMBINING_CLASS_ABOVE;
156 case HB_MODIFIED_COMBINING_CLASS_CCC132: /* sign u */
157 return HB_UNICODE_COMBINING_CLASS_BELOW;
165 _hb_ot_shape_fallback_position_recategorize_marks (const hb_ot_shape_plan_t *plan HB_UNUSED,
166 hb_font_t *font HB_UNUSED,
169 unsigned int count = buffer->len;
170 hb_glyph_info_t *info = buffer->info;
171 for (unsigned int i = 0; i < count; i++)
172 if (_hb_glyph_info_get_general_category (&info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) {
173 unsigned int combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]);
174 combining_class = recategorize_combining_class (info[i].codepoint, combining_class);
175 _hb_glyph_info_set_modified_combining_class (&info[i], combining_class);
181 zero_mark_advances (hb_buffer_t *buffer,
185 hb_glyph_info_t *info = buffer->info;
186 for (unsigned int i = start; i < end; i++)
187 if (_hb_glyph_info_get_general_category (&info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)
189 buffer->pos[i].x_advance = 0;
190 buffer->pos[i].y_advance = 0;
195 position_mark (const hb_ot_shape_plan_t *plan,
198 hb_glyph_extents_t &base_extents,
200 unsigned int combining_class)
202 hb_glyph_extents_t mark_extents;
203 if (!font->get_glyph_extents (buffer->info[i].codepoint, &mark_extents))
206 hb_position_t y_gap = font->y_scale / 16;
208 hb_glyph_position_t &pos = buffer->pos[i];
209 pos.x_offset = pos.y_offset = 0;
212 /* We don't position LEFT and RIGHT marks. */
215 switch (combining_class)
217 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
218 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
219 if (buffer->props.direction == HB_DIRECTION_LTR) {
220 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing;
222 } else if (buffer->props.direction == HB_DIRECTION_RTL) {
223 pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing;
229 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
230 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
231 case HB_UNICODE_COMBINING_CLASS_BELOW:
232 case HB_UNICODE_COMBINING_CLASS_ABOVE:
234 pos.x_offset += base_extents.x_bearing + (base_extents.width - mark_extents.width) / 2 - mark_extents.x_bearing;
237 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
238 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
239 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
241 pos.x_offset += base_extents.x_bearing - mark_extents.x_bearing;
244 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
245 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
246 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
248 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width - mark_extents.x_bearing;
253 switch (combining_class)
255 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
256 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
257 case HB_UNICODE_COMBINING_CLASS_BELOW:
258 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
259 /* Add gap, fall-through. */
260 base_extents.height -= y_gap;
263 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
264 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
265 pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing;
266 /* Never shift up "below" marks. */
267 if ((y_gap > 0) == (pos.y_offset > 0))
269 base_extents.height -= pos.y_offset;
272 base_extents.height += mark_extents.height;
275 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
276 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
277 case HB_UNICODE_COMBINING_CLASS_ABOVE:
278 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
279 /* Add gap, fall-through. */
280 base_extents.y_bearing += y_gap;
281 base_extents.height -= y_gap;
284 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
285 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
286 pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height);
287 /* Don't shift down "above" marks too much. */
288 if ((y_gap > 0) != (pos.y_offset > 0))
290 unsigned int correction = -pos.y_offset / 2;
291 base_extents.y_bearing += correction;
292 base_extents.height -= correction;
293 pos.y_offset += correction;
295 base_extents.y_bearing -= mark_extents.height;
296 base_extents.height += mark_extents.height;
302 position_around_base (const hb_ot_shape_plan_t *plan,
308 hb_direction_t horiz_dir = HB_DIRECTION_INVALID;
310 buffer->unsafe_to_break (base, end);
312 hb_glyph_extents_t base_extents;
313 if (!font->get_glyph_extents (buffer->info[base].codepoint,
316 /* If extents don't work, zero marks and go home. */
317 zero_mark_advances (buffer, base + 1, end);
320 base_extents.x_bearing += buffer->pos[base].x_offset;
321 base_extents.y_bearing += buffer->pos[base].y_offset;
323 unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]);
324 /* Use integer for num_lig_components such that it doesn't convert to unsigned
325 * when we divide or multiply by it. */
326 int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]);
328 hb_position_t x_offset = 0, y_offset = 0;
329 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
330 x_offset -= buffer->pos[base].x_advance;
331 y_offset -= buffer->pos[base].y_advance;
334 hb_glyph_extents_t component_extents = base_extents;
335 int last_lig_component = -1;
336 unsigned int last_combining_class = 255;
337 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */
338 hb_glyph_info_t *info = buffer->info;
339 for (unsigned int i = base + 1; i < end; i++)
340 if (_hb_glyph_info_get_modified_combining_class (&info[i]))
342 if (num_lig_components > 1) {
343 unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&info[i]);
344 int this_lig_component = _hb_glyph_info_get_lig_comp (&info[i]) - 1;
345 /* Conditions for attaching to the last component. */
346 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components)
347 this_lig_component = num_lig_components - 1;
348 if (last_lig_component != this_lig_component)
350 last_lig_component = this_lig_component;
351 last_combining_class = 255;
352 component_extents = base_extents;
353 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) {
354 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction))
355 horiz_dir = plan->props.direction;
357 horiz_dir = hb_script_get_horizontal_direction (plan->props.script);
359 if (horiz_dir == HB_DIRECTION_LTR)
360 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components;
362 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components;
363 component_extents.width /= num_lig_components;
367 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]);
368 if (last_combining_class != this_combining_class)
370 last_combining_class = this_combining_class;
371 cluster_extents = component_extents;
374 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class);
376 buffer->pos[i].x_advance = 0;
377 buffer->pos[i].y_advance = 0;
378 buffer->pos[i].x_offset += x_offset;
379 buffer->pos[i].y_offset += y_offset;
382 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
383 x_offset -= buffer->pos[i].x_advance;
384 y_offset -= buffer->pos[i].y_advance;
386 x_offset += buffer->pos[i].x_advance;
387 y_offset += buffer->pos[i].y_advance;
393 position_cluster (const hb_ot_shape_plan_t *plan,
402 /* Find the base glyph */
403 hb_glyph_info_t *info = buffer->info;
404 for (unsigned int i = start; i < end; i++)
405 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])))
407 /* Find mark glyphs */
409 for (j = i + 1; j < end; j++)
410 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[j])))
413 position_around_base (plan, font, buffer, i, j);
420 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan,
424 _hb_buffer_assert_gsubgpos_vars (buffer);
426 unsigned int start = 0;
427 unsigned int count = buffer->len;
428 hb_glyph_info_t *info = buffer->info;
429 for (unsigned int i = 1; i < count; i++)
430 if (likely (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])))) {
431 position_cluster (plan, font, buffer, start, i);
434 position_cluster (plan, font, buffer, start, count);
438 /* Performs old-style TrueType kerning. */
440 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
444 if (!plan->has_kern) return;
446 OT::hb_ot_apply_context_t c (1, font, buffer);
447 c.set_lookup_mask (plan->kern_mask);
448 c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
449 OT::hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input;
450 skippy_iter.init (&c);
452 unsigned int count = buffer->len;
453 hb_glyph_info_t *info = buffer->info;
454 hb_glyph_position_t *pos = buffer->pos;
455 for (unsigned int idx = 0; idx < count;)
457 skippy_iter.reset (idx, 1);
458 if (!skippy_iter.next ())
464 hb_position_t x_kern, y_kern;
465 font->get_glyph_kerning_for_direction (info[idx].codepoint,
466 info[skippy_iter.idx].codepoint,
467 buffer->props.direction,
472 hb_position_t kern1 = x_kern >> 1;
473 hb_position_t kern2 = x_kern - kern1;
474 pos[idx].x_advance += kern1;
475 pos[skippy_iter.idx].x_advance += kern2;
476 pos[skippy_iter.idx].x_offset += kern2;
477 buffer->unsafe_to_break (idx, skippy_iter.idx + 1);
482 hb_position_t kern1 = y_kern >> 1;
483 hb_position_t kern2 = y_kern - kern1;
484 pos[idx].y_advance += kern1;
485 pos[skippy_iter.idx].y_advance += kern2;
486 pos[skippy_iter.idx].y_offset += kern2;
487 buffer->unsafe_to_break (idx, skippy_iter.idx + 1);
490 idx = skippy_iter.idx;
495 /* Adjusts width of various spaces. */
497 _hb_ot_shape_fallback_spaces (const hb_ot_shape_plan_t *plan,
501 if (!HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
504 hb_glyph_info_t *info = buffer->info;
505 hb_glyph_position_t *pos = buffer->pos;
506 unsigned int count = buffer->len;
507 for (unsigned int i = 0; i < count; i++)
508 if (_hb_glyph_info_is_unicode_space (&info[i]) && !_hb_glyph_info_ligated (&info[i]))
510 hb_unicode_funcs_t::space_t space_type = _hb_glyph_info_get_unicode_space_fallback_type (&info[i]);
511 hb_codepoint_t glyph;
512 typedef hb_unicode_funcs_t t;
515 case t::NOT_SPACE: /* Shouldn't happen. */
526 pos[i].x_advance = (font->x_scale + ((int) space_type)/2) / (int) space_type;
529 case t::SPACE_4_EM_18:
530 pos[i].x_advance = (int64_t) font->x_scale * 4 / 18;
533 case t::SPACE_FIGURE:
534 for (char u = '0'; u <= '9'; u++)
535 if (font->get_nominal_glyph (u, &glyph))
537 pos[i].x_advance = font->get_glyph_h_advance (glyph);
542 case t::SPACE_PUNCTUATION:
543 if (font->get_nominal_glyph ('.', &glyph))
544 pos[i].x_advance = font->get_glyph_h_advance (glyph);
545 else if (font->get_nominal_glyph (',', &glyph))
546 pos[i].x_advance = font->get_glyph_h_advance (glyph);
549 case t::SPACE_NARROW:
551 * Unicode doc http://www.unicode.org/charts/PDF/U2000.pdf says ~1/4 or 1/5 of EM.
552 * However, in my testing, many fonts have their regular space being about that
553 * size. To me, a percentage of the space width makes more sense. Half is as
555 pos[i].x_advance /= 2;