1 /*
2 * Copyright © 2010,2012 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-complex-arabic-private.hh"
28 #include "hb-ot-shape-private.hh"
29
30
31 #ifndef HB_DEBUG_ARABIC
32 #define HB_DEBUG_ARABIC (HB_DEBUG+0)
33 #endif
34
35
36 /* buffer var allocations */
37 #define arabic_shaping_action() complex_var_u8_0() /* arabic shaping action */
38
39 #define HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH HB_BUFFER_SCRATCH_FLAG_COMPLEX0
40
41 /* See:
42 * https://github.com/behdad/harfbuzz/commit/6e6f82b6f3dde0fc6c3c7d991d9ec6cfff57823d#commitcomment-14248516 */
43 #define HB_ARABIC_GENERAL_CATEGORY_IS_WORD(gen_cat) \
44 (FLAG_SAFE (gen_cat) & \
45 (FLAG (HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED) | \
46 FLAG (HB_UNICODE_GENERAL_CATEGORY_PRIVATE_USE) | \
47 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) |*/ \
48 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) | \
49 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) | \
50 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) |*/ \
51 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) |*/ \
52 FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \
53 FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | \
54 FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | \
55 FLAG (HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER) | \
56 FLAG (HB_UNICODE_GENERAL_CATEGORY_LETTER_NUMBER) | \
57 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_NUMBER) | \
58 FLAG (HB_UNICODE_GENERAL_CATEGORY_CURRENCY_SYMBOL) | \
59 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_SYMBOL) | \
60 FLAG (HB_UNICODE_GENERAL_CATEGORY_MATH_SYMBOL) | \
61 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_SYMBOL)))
62
63
64 /*
65 * Joining types:
66 */
67
68 /*
69 * Bits used in the joining tables
70 */
71 enum hb_arabic_joining_type_t {
72 JOINING_TYPE_U = 0,
73 JOINING_TYPE_L = 1,
74 JOINING_TYPE_R = 2,
75 JOINING_TYPE_D = 3,
76 JOINING_TYPE_C = JOINING_TYPE_D,
77 JOINING_GROUP_ALAPH = 4,
78 JOINING_GROUP_DALATH_RISH = 5,
79 NUM_STATE_MACHINE_COLS = 6,
80
81 JOINING_TYPE_T = 7,
82 JOINING_TYPE_X = 8 /* means: use general-category to choose between U or T. */
83 };
84
85 #include "hb-ot-shape-complex-arabic-table.hh"
86
87 static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat)
88 {
89 unsigned int j_type = joining_type(u);
90 if (likely (j_type != JOINING_TYPE_X))
91 return j_type;
92
93 return (FLAG_SAFE(gen_cat) &
94 (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) |
95 FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
96 FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT))
97 ) ? JOINING_TYPE_T : JOINING_TYPE_U;
98 }
99
100 #define FEATURE_IS_SYRIAC(tag) hb_in_range<unsigned char> ((unsigned char) (tag), '2', '3')
101
102 static const hb_tag_t arabic_features[] =
103 {
104 HB_TAG('i','s','o','l'),
105 HB_TAG('f','i','n','a'),
106 HB_TAG('f','i','n','2'),
107 HB_TAG('f','i','n','3'),
108 HB_TAG('m','e','d','i'),
109 HB_TAG('m','e','d','2'),
110 HB_TAG('i','n','i','t'),
111 HB_TAG_NONE
112 };
113
114
115 /* Same order as the feature array */
116 enum arabic_action_t {
117 ISOL,
118 FINA,
119 FIN2,
120 FIN3,
121 MEDI,
122 MED2,
123 INIT,
124
125 NONE,
126
127 ARABIC_NUM_FEATURES = NONE,
128
129 /* We abuse the same byte for other things... */
130 STCH_FIXED,
131 STCH_REPEATING,
132 };
133
134 static const struct arabic_state_table_entry {
135 uint8_t prev_action;
136 uint8_t curr_action;
137 uint16_t next_state;
138 } arabic_state_table[][NUM_STATE_MACHINE_COLS] =
139 {
140 /* jt_U, jt_L, jt_R, jt_D, jg_ALAPH, jg_DALATH_RISH */
141
142 /* State 0: prev was U, not willing to join. */
143 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,6}, },
144
145 /* State 1: prev was R or ISOL/ALAPH, not willing to join. */
146 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN2,5}, {NONE,ISOL,6}, },
147
148 /* State 2: prev was D/L in ISOL form, willing to join. */
149 { {NONE,NONE,0}, {NONE,ISOL,2}, {INIT,FINA,1}, {INIT,FINA,3}, {INIT,FINA,4}, {INIT,FINA,6}, },
150
151 /* State 3: prev was D in FINA form, willing to join. */
152 { {NONE,NONE,0}, {NONE,ISOL,2}, {MEDI,FINA,1}, {MEDI,FINA,3}, {MEDI,FINA,4}, {MEDI,FINA,6}, },
153
154 /* State 4: prev was FINA ALAPH, not willing to join. */
155 { {NONE,NONE,0}, {NONE,ISOL,2}, {MED2,ISOL,1}, {MED2,ISOL,2}, {MED2,FIN2,5}, {MED2,ISOL,6}, },
156
157 /* State 5: prev was FIN2/FIN3 ALAPH, not willing to join. */
158 { {NONE,NONE,0}, {NONE,ISOL,2}, {ISOL,ISOL,1}, {ISOL,ISOL,2}, {ISOL,FIN2,5}, {ISOL,ISOL,6}, },
159
160 /* State 6: prev was DALATH/RISH, not willing to join. */
161 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN3,5}, {NONE,ISOL,6}, }
162 };
163
164
165 static void
166 nuke_joiners (const hb_ot_shape_plan_t *plan,
167 hb_font_t *font,
168 hb_buffer_t *buffer);
169
170 static void
171 arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
172 hb_font_t *font,
173 hb_buffer_t *buffer);
174
175 static void
176 record_stch (const hb_ot_shape_plan_t *plan,
177 hb_font_t *font,
178 hb_buffer_t *buffer);
179
180 static void
181 collect_features_arabic (hb_ot_shape_planner_t *plan)
182 {
183 hb_ot_map_builder_t *map = &plan->map;
184
185 /* We apply features according to the Arabic spec, with pauses
186 * in between most.
187 *
188 * The pause between init/medi/... and rlig is required. See eg:
189 * https://bugzilla.mozilla.org/show_bug.cgi?id=644184
190 *
191 * The pauses between init/medi/... themselves are not necessarily
192 * needed as only one of those features is applied to any character.
193 * The only difference it makes is when fonts have contextual
194 * substitutions. We now follow the order of the spec, which makes
195 * for better experience if that's what Uniscribe is doing.
196 *
197 * At least for Arabic, looks like Uniscribe has a pause between
198 * rlig and calt. Otherwise the IranNastaliq's ALLAH ligature won't
199 * work. However, testing shows that rlig and calt are applied
200 * together for Mongolian in Uniscribe. As such, we only add a
201 * pause for Arabic, not other scripts.
202 */
203
204 map->add_gsub_pause (nuke_joiners);
205
206 map->add_global_bool_feature (HB_TAG('s','t','c','h'));
207 map->add_gsub_pause (record_stch);
208
209 map->add_global_bool_feature (HB_TAG('c','c','m','p'));
210 map->add_global_bool_feature (HB_TAG('l','o','c','l'));
211
212 map->add_gsub_pause (NULL);
213
214 for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++)
215 {
216 bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]);
217 map->add_feature (arabic_features[i], 1, has_fallback ? F_HAS_FALLBACK : F_NONE);
218 map->add_gsub_pause (NULL);
219 }
220
221 map->add_feature (HB_TAG('r','l','i','g'), 1, F_GLOBAL|F_HAS_FALLBACK);
222 if (plan->props.script == HB_SCRIPT_ARABIC)
223 map->add_gsub_pause (arabic_fallback_shape);
224
225 map->add_global_bool_feature (HB_TAG('c','a','l','t'));
226
227 /* The spec includes 'cswh'. Earlier versions of Windows
228 * used to enable this by default, but testing suggests
229 * that Windows 8 and later do not enable it by default,
230 * and spec now says 'Off by default'.
231 * We disabled this in ae23c24c32.
232 * Note that IranNastaliq uses this feature extensively
233 * to fixup broken glyph sequences. Oh well...
234 * Test case: U+0643,U+0640,U+0631. */
235 //map->add_gsub_pause (NULL);
236 //map->add_global_bool_feature (HB_TAG('c','s','w','h'));
237 map->add_global_bool_feature (HB_TAG('m','s','e','t'));
238 }
239
240 #include "hb-ot-shape-complex-arabic-fallback.hh"
241
242 struct arabic_shape_plan_t
243 {
244 ASSERT_POD ();
245
246 /* The "+ 1" in the next array is to accommodate for the "NONE" command,
247 * which is not an OpenType feature, but this simplifies the code by not
248 * having to do a "if (... < NONE) ..." and just rely on the fact that
249 * mask_array[NONE] == 0. */
250 hb_mask_t mask_array[ARABIC_NUM_FEATURES + 1];
251
252 arabic_fallback_plan_t *fallback_plan;
253
254 unsigned int do_fallback : 1;
255 unsigned int has_stch : 1;
256 };
257
258 void *
259 data_create_arabic (const hb_ot_shape_plan_t *plan)
260 {
261 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t));
262 if (unlikely (!arabic_plan))
263 return NULL;
264
265 arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC;
266 arabic_plan->has_stch = !!plan->map.get_1_mask (HB_TAG ('s','t','c','h'));
267 for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) {
268 arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]);
269 arabic_plan->do_fallback = arabic_plan->do_fallback &&
270 (FEATURE_IS_SYRIAC (arabic_features[i]) ||
271 plan->map.needs_fallback (arabic_features[i]));
272 }
273
274 return arabic_plan;
275 }
276
277 void
278 data_destroy_arabic (void *data)
279 {
280 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) data;
281
282 arabic_fallback_plan_destroy (arabic_plan->fallback_plan);
283
284 free (data);
285 }
286
287 static void
288 arabic_joining (hb_buffer_t *buffer)
289 {
290 unsigned int count = buffer->len;
291 hb_glyph_info_t *info = buffer->info;
292 unsigned int prev = (unsigned int) -1, state = 0;
293
294 /* Check pre-context */
295 for (unsigned int i = 0; i < buffer->context_len[0]; i++)
296 {
297 unsigned int this_type = get_joining_type (buffer->context[0][i], buffer->unicode->general_category (buffer->context[0][i]));
298
299 if (unlikely (this_type == JOINING_TYPE_T))
300 continue;
301
302 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
303 state = entry->next_state;
304 break;
305 }
306
307 for (unsigned int i = 0; i < count; i++)
308 {
309 unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i]));
310
311 if (unlikely (this_type == JOINING_TYPE_T)) {
312 info[i].arabic_shaping_action() = NONE;
313 continue;
314 }
315
316 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
317
318 if (entry->prev_action != NONE && prev != (unsigned int) -1)
319 info[prev].arabic_shaping_action() = entry->prev_action;
320
321 info[i].arabic_shaping_action() = entry->curr_action;
322
323 prev = i;
324 state = entry->next_state;
325 }
326
327 for (unsigned int i = 0; i < buffer->context_len[1]; i++)
328 {
329 unsigned int this_type = get_joining_type (buffer->context[1][i], buffer->unicode->general_category (buffer->context[1][i]));
330
331 if (unlikely (this_type == JOINING_TYPE_T))
332 continue;
333
334 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
335 if (entry->prev_action != NONE && prev != (unsigned int) -1)
336 info[prev].arabic_shaping_action() = entry->prev_action;
337 break;
338 }
339 }
340
341 static void
342 mongolian_variation_selectors (hb_buffer_t *buffer)
343 {
344 /* Copy arabic_shaping_action() from base to Mongolian variation selectors. */
345 unsigned int count = buffer->len;
346 hb_glyph_info_t *info = buffer->info;
347 for (unsigned int i = 1; i < count; i++)
348 if (unlikely (hb_in_range (info[i].codepoint, 0x180Bu, 0x180Du)))
349 info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action();
350 }
351
352 void
353 setup_masks_arabic_plan (const arabic_shape_plan_t *arabic_plan,
354 hb_buffer_t *buffer,
355 hb_script_t script)
356 {
357 HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
358
359 arabic_joining (buffer);
360 if (script == HB_SCRIPT_MONGOLIAN)
361 mongolian_variation_selectors (buffer);
362
363 unsigned int count = buffer->len;
364 hb_glyph_info_t *info = buffer->info;
365 for (unsigned int i = 0; i < count; i++)
366 info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()];
367 }
368
369 static void
370 setup_masks_arabic (const hb_ot_shape_plan_t *plan,
371 hb_buffer_t *buffer,
372 hb_font_t *font HB_UNUSED)
373 {
374 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
375 setup_masks_arabic_plan (arabic_plan, buffer, plan->props.script);
376 }
377
378
379 static void
380 nuke_joiners (const hb_ot_shape_plan_t *plan HB_UNUSED,
381 hb_font_t *font HB_UNUSED,
382 hb_buffer_t *buffer)
383 {
384 unsigned int count = buffer->len;
385 hb_glyph_info_t *info = buffer->info;
386 for (unsigned int i = 0; i < count; i++)
387 if (_hb_glyph_info_is_zwj (&info[i]))
388 _hb_glyph_info_flip_joiners (&info[i]);
389 }
390
391 static void
392 arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
393 hb_font_t *font,
394 hb_buffer_t *buffer)
395 {
396 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
397
398 if (!arabic_plan->do_fallback)
399 return;
400
401 retry:
402 arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) hb_atomic_ptr_get (&arabic_plan->fallback_plan);
403 if (unlikely (!fallback_plan))
404 {
405 /* This sucks. We need a font to build the fallback plan... */
406 fallback_plan = arabic_fallback_plan_create (plan, font);
407 if (unlikely (!hb_atomic_ptr_cmpexch (&(const_cast<arabic_shape_plan_t *> (arabic_plan))->fallback_plan, NULL, fallback_plan))) {
408 arabic_fallback_plan_destroy (fallback_plan);
409 goto retry;
410 }
411 }
412
413 arabic_fallback_plan_shape (fallback_plan, font, buffer);
414 }
415
416 /*
417 * Stretch feature: "stch".
418 * See example here:
419 * https://www.microsoft.com/typography/OpenTypeDev/syriac/intro.htm
420 * We implement this in a generic way, such that the Arabic subtending
421 * marks can use it as well.
422 */
423
424 static void
425 record_stch (const hb_ot_shape_plan_t *plan,
426 hb_font_t *font,
427 hb_buffer_t *buffer)
428 {
429 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
430 if (!arabic_plan->has_stch)
431 return;
432
433 /* 'stch' feature was just applied. Look for anything that multiplied,
434 * and record it for stch treatment later. Note that rtlm, frac, etc
435 * are applied before stch, but we assume that they didn't result in
436 * anything multiplying into 5 pieces, so it's safe-ish... */
437
438 unsigned int count = buffer->len;
439 hb_glyph_info_t *info = buffer->info;
440 for (unsigned int i = 0; i < count; i++)
441 if (unlikely (_hb_glyph_info_multiplied (&info[i])))
442 {
443 unsigned int comp = _hb_glyph_info_get_lig_comp (&info[i]);
444 info[i].arabic_shaping_action() = comp % 2 ? STCH_REPEATING : STCH_FIXED;
445 buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH;
446 }
447 }
448
449 static void
450 apply_stch (const hb_ot_shape_plan_t *plan,
451 hb_buffer_t *buffer,
452 hb_font_t *font)
453 {
454 if (likely (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH)))
455 return;
456
457 /* The Arabic shaper currently always processes in RTL mode, so we should
458 * stretch / position the stretched pieces to the left / preceding glyphs. */
459
460 /* We do a two pass implementation:
461 * First pass calculates the exact number of extra glyphs we need,
462 * We then enlarge buffer to have that much room,
463 * Second pass applies the stretch, copying things to the end of buffer.
464 */
465
466 int sign = font->x_scale < 0 ? -1 : +1;
467 unsigned int extra_glyphs_needed = 0; // Set during MEASURE, used during CUT
468 typedef enum { MEASURE, CUT } step_t;
469
470 for (step_t step = MEASURE; step <= CUT; step = (step_t) (step + 1))
471 {
472 unsigned int count = buffer->len;
473 hb_glyph_info_t *info = buffer->info;
474 hb_glyph_position_t *pos = buffer->pos;
475 unsigned int new_len = count + extra_glyphs_needed; // write head during CUT
476 unsigned int j = new_len;
477 for (unsigned int i = count; i; i--)
478 {
479 if (!hb_in_range<unsigned> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING))
480 {
481 if (step == CUT)
482 {
483 --j;
484 info[j] = info[i - 1];
485 pos[j] = pos[i - 1];
486 }
487 continue;
488 }
489
490 /* Yay, justification! */
491
492 hb_position_t w_total = 0; // Total to be filled
493 hb_position_t w_fixed = 0; // Sum of fixed tiles
494 hb_position_t w_repeating = 0; // Sum of repeating tiles
495 int n_fixed = 0;
496 int n_repeating = 0;
497
498 unsigned int end = i;
499 while (i &&
500 hb_in_range<unsigned> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING))
501 {
502 i--;
503 hb_position_t width = font->get_glyph_h_advance (info[i].codepoint);
504 if (info[i].arabic_shaping_action() == STCH_FIXED)
505 {
506 w_fixed += width;
507 n_fixed++;
508 }
509 else
510 {
511 w_repeating += width;
512 n_repeating++;
513 }
514 }
515 unsigned int start = i;
516 unsigned int context = i;
517 while (context &&
518 !hb_in_range<unsigned> (info[context - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING) &&
519 (_hb_glyph_info_is_default_ignorable (&info[context - 1]) ||
520 HB_ARABIC_GENERAL_CATEGORY_IS_WORD (_hb_glyph_info_get_general_category (&info[context - 1]))))
521 {
522 context--;
523 w_total += pos[context].x_advance;
524 }
525 i++; // Don't touch i again.
526
527 DEBUG_MSG (ARABIC, NULL, "%s stretch at (%d,%d,%d)",
528 step == MEASURE ? "measuring" : "cutting", context, start, end);
529 DEBUG_MSG (ARABIC, NULL, "rest of word: count=%d width %d", start - context, w_total);
530 DEBUG_MSG (ARABIC, NULL, "fixed tiles: count=%d width=%d", n_fixed, w_fixed);
531 DEBUG_MSG (ARABIC, NULL, "repeating tiles: count=%d width=%d", n_repeating, w_repeating);
532
533 /* Number of additional times to repeat each repeating tile. */
534 int n_copies = 0;
535
536 hb_position_t w_remaining = w_total - w_fixed;
537 if (sign * w_remaining > sign * w_repeating && sign * w_repeating > 0)
538 n_copies = (sign * w_remaining) / (sign * w_repeating) - 1;
539
540 /* See if we can improve the fit by adding an extra repeat and squeezing them together a bit. */
541 hb_position_t extra_repeat_overlap = 0;
542 hb_position_t shortfall = sign * w_remaining - sign * w_repeating * (n_copies + 1);
543 if (shortfall > 0)
544 {
545 ++n_copies;
546 hb_position_t excess = (n_copies + 1) * sign * w_repeating - sign * w_remaining;
547 if (excess > 0)
548 extra_repeat_overlap = excess / (n_copies * n_repeating);
549 }
550
551 if (step == MEASURE)
552 {
553 extra_glyphs_needed += n_copies * n_repeating;
554 DEBUG_MSG (ARABIC, NULL, "will add extra %d copies of repeating tiles", n_copies);
555 }
556 else
557 {
558 hb_position_t x_offset = 0;
559 for (unsigned int k = end; k > start; k--)
560 {
561 hb_position_t width = font->get_glyph_h_advance (info[k - 1].codepoint);
562
563 unsigned int repeat = 1;
564 if (info[k - 1].arabic_shaping_action() == STCH_REPEATING)
565 repeat += n_copies;
566
567 DEBUG_MSG (ARABIC, NULL, "appending %d copies of glyph %d; j=%d",
568 repeat, info[k - 1].codepoint, j);
569 for (unsigned int n = 0; n < repeat; n++)
570 {
571 x_offset -= width;
572 if (n > 0)
573 x_offset += extra_repeat_overlap;
574 pos[k - 1].x_offset = x_offset;
575 /* Append copy. */
576 --j;
577 info[j] = info[k - 1];
578 pos[j] = pos[k - 1];
579 }
580 }
581 }
582 }
583
584 if (step == MEASURE)
585 {
586 if (unlikely (!buffer->ensure (count + extra_glyphs_needed)))
587 break;
588 }
589 else
590 {
591 assert (j == 0);
592 buffer->len = new_len;
593 }
594 }
595 }
596
597
598 static void
599 postprocess_glyphs_arabic (const hb_ot_shape_plan_t *plan,
600 hb_buffer_t *buffer,
601 hb_font_t *font)
602 {
603 apply_stch (plan, buffer, font);
604
605 HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
606 }
607
608 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic =
609 {
610 "arabic",
611 collect_features_arabic,
612 NULL, /* override_features */
613 data_create_arabic,
614 data_destroy_arabic,
615 NULL, /* preprocess_text */
616 postprocess_glyphs_arabic,
617 HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
618 NULL, /* decompose */
619 NULL, /* compose */
620 setup_masks_arabic,
621 NULL, /* disable_otl */
622 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
623 true, /* fallback_position */
624 };