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 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, 622 true, /* fallback_position */ 623 }; 624
