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,
207 hb_position_t y_gap = font->y_scale / 16;
209 hb_glyph_position_t &pos = buffer->pos[i];
210 pos.x_offset = pos.y_offset = 0;
213 /* We dont position LEFT and RIGHT marks. */
216 switch (combining_class)
218 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
219 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
220 if (buffer->props.direction == HB_DIRECTION_LTR) {
221 pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing;
223 } else if (buffer->props.direction == HB_DIRECTION_RTL) {
224 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing;
230 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
231 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
232 case HB_UNICODE_COMBINING_CLASS_BELOW:
233 case HB_UNICODE_COMBINING_CLASS_ABOVE:
235 pos.x_offset += base_extents.x_bearing + (base_extents.width - mark_extents.width) / 2 - mark_extents.x_bearing;
238 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
239 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
240 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
242 pos.x_offset += base_extents.x_bearing - mark_extents.x_bearing;
245 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
246 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
247 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
249 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width - mark_extents.x_bearing;
254 switch (combining_class)
256 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
257 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT:
258 case HB_UNICODE_COMBINING_CLASS_BELOW:
259 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT:
260 /* Add gap, fall-through. */
261 base_extents.height -= y_gap;
264 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
265 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
266 pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing;
267 /* Never shift up "below" marks. */
268 if ((y_gap > 0) == (pos.y_offset > 0))
270 base_extents.height -= pos.y_offset;
273 base_extents.height += mark_extents.height;
276 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
277 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT:
278 case HB_UNICODE_COMBINING_CLASS_ABOVE:
279 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT:
280 /* Add gap, fall-through. */
281 base_extents.y_bearing += y_gap;
282 base_extents.height -= y_gap;
285 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
286 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
287 pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height);
288 /* Don't shift down "above" marks too much. */
289 if ((y_gap > 0) != (pos.y_offset > 0))
291 unsigned int correction = -pos.y_offset / 2;
292 base_extents.y_bearing += correction;
293 base_extents.height -= correction;
294 pos.y_offset += correction;
296 base_extents.y_bearing -= mark_extents.height;
297 base_extents.height += mark_extents.height;
303 position_around_base (const hb_ot_shape_plan_t *plan,
309 hb_direction_t horiz_dir = HB_DIRECTION_INVALID;
310 hb_glyph_extents_t base_extents;
311 if (!font->get_glyph_extents (buffer->info[base].codepoint,
314 /* If extents don't work, zero marks and go home. */
315 zero_mark_advances (buffer, base + 1, end);
318 base_extents.x_bearing += buffer->pos[base].x_offset;
319 base_extents.y_bearing += buffer->pos[base].y_offset;
321 unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]);
322 unsigned int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]);
324 hb_position_t x_offset = 0, y_offset = 0;
325 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
326 x_offset -= buffer->pos[base].x_advance;
327 y_offset -= buffer->pos[base].y_advance;
330 hb_glyph_extents_t component_extents = base_extents;
331 unsigned int last_lig_component = (unsigned int) -1;
332 unsigned int last_combining_class = 255;
333 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */
334 hb_glyph_info_t *info = buffer->info;
335 for (unsigned int i = base + 1; i < end; i++)
336 if (_hb_glyph_info_get_modified_combining_class (&info[i]))
338 if (num_lig_components > 1) {
339 unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&info[i]);
340 unsigned int this_lig_component = _hb_glyph_info_get_lig_comp (&info[i]) - 1;
341 /* Conditions for attaching to the last component. */
342 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components)
343 this_lig_component = num_lig_components - 1;
344 if (last_lig_component != this_lig_component)
346 last_lig_component = this_lig_component;
347 last_combining_class = 255;
348 component_extents = base_extents;
349 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) {
350 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction))
351 horiz_dir = plan->props.direction;
353 horiz_dir = hb_script_get_horizontal_direction (plan->props.script);
355 if (horiz_dir == HB_DIRECTION_LTR)
356 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components;
358 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components;
359 component_extents.width /= num_lig_components;
363 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]);
364 if (last_combining_class != this_combining_class)
366 last_combining_class = this_combining_class;
367 cluster_extents = component_extents;
370 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class);
372 buffer->pos[i].x_advance = 0;
373 buffer->pos[i].y_advance = 0;
374 buffer->pos[i].x_offset += x_offset;
375 buffer->pos[i].y_offset += y_offset;
378 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
379 x_offset -= buffer->pos[i].x_advance;
380 y_offset -= buffer->pos[i].y_advance;
382 x_offset += buffer->pos[i].x_advance;
383 y_offset += buffer->pos[i].y_advance;
389 position_cluster (const hb_ot_shape_plan_t *plan,
398 /* Find the base glyph */
399 hb_glyph_info_t *info = buffer->info;
400 for (unsigned int i = start; i < end; i++)
401 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])))
403 /* Find mark glyphs */
405 for (j = i + 1; j < end; j++)
406 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[j])))
409 position_around_base (plan, font, buffer, i, j);
416 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan,
420 _hb_buffer_assert_gsubgpos_vars (buffer);
422 unsigned int start = 0;
423 unsigned int count = buffer->len;
424 hb_glyph_info_t *info = buffer->info;
425 for (unsigned int i = 1; i < count; i++)
426 if (likely (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])))) {
427 position_cluster (plan, font, buffer, start, i);
430 position_cluster (plan, font, buffer, start, count);
434 /* Performs old-style TrueType kerning. */
436 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
440 if (!plan->has_kern) return;
442 OT::hb_apply_context_t c (1, font, buffer);
443 c.set_lookup_mask (plan->kern_mask);
444 c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
445 OT::hb_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input;
446 skippy_iter.init (&c);
448 unsigned int count = buffer->len;
449 hb_glyph_info_t *info = buffer->info;
450 hb_glyph_position_t *pos = buffer->pos;
451 for (unsigned int idx = 0; idx < count;)
453 skippy_iter.reset (idx, 1);
454 if (!skippy_iter.next ())
460 hb_position_t x_kern, y_kern;
461 font->get_glyph_kerning_for_direction (info[idx].codepoint,
462 info[skippy_iter.idx].codepoint,
463 buffer->props.direction,
468 hb_position_t kern1 = x_kern >> 1;
469 hb_position_t kern2 = x_kern - kern1;
470 pos[idx].x_advance += kern1;
471 pos[skippy_iter.idx].x_advance += kern2;
472 pos[skippy_iter.idx].x_offset += kern2;
477 hb_position_t kern1 = y_kern >> 1;
478 hb_position_t kern2 = y_kern - kern1;
479 pos[idx].y_advance += kern1;
480 pos[skippy_iter.idx].y_advance += kern2;
481 pos[skippy_iter.idx].y_offset += kern2;
484 idx = skippy_iter.idx;
489 /* Adjusts width of various spaces. */
491 _hb_ot_shape_fallback_spaces (const hb_ot_shape_plan_t *plan,
495 if (!HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
498 hb_glyph_info_t *info = buffer->info;
499 hb_glyph_position_t *pos = buffer->pos;
500 unsigned int count = buffer->len;
501 for (unsigned int i = 0; i < count; i++)
502 if (_hb_glyph_info_is_unicode_space (&info[i]) && !_hb_glyph_info_ligated (&info[i]))
504 hb_unicode_funcs_t::space_t space_type = _hb_glyph_info_get_unicode_space_fallback_type (&info[i]);
505 hb_codepoint_t glyph;
506 typedef hb_unicode_funcs_t t;
509 case t::NOT_SPACE: /* Shouldn't happen. */
520 pos[i].x_advance = (font->x_scale + ((int) space_type)/2) / (int) space_type;
523 case t::SPACE_4_EM_18:
524 pos[i].x_advance = font->x_scale * 4 / 18;
527 case t::SPACE_FIGURE:
528 for (char u = '0'; u <= '9'; u++)
529 if (font->get_nominal_glyph (u, &glyph))
531 pos[i].x_advance = font->get_glyph_h_advance (glyph);
536 case t::SPACE_PUNCTUATION:
537 if (font->get_nominal_glyph ('.', &glyph))
538 pos[i].x_advance = font->get_glyph_h_advance (glyph);
539 else if (font->get_nominal_glyph (',', &glyph))
540 pos[i].x_advance = font->get_glyph_h_advance (glyph);
543 case t::SPACE_NARROW:
545 * Unicode doc http://www.unicode.org/charts/PDF/U2000.pdf says ~1/4 or 1/5 of EM.
546 * However, in my testing, many fonts have their regular space being about that
547 * size. To me, a percentage of the space width makes more sense. Half is as
549 pos[i].x_advance /= 2;