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-private.hh" 28 #include "hb-debug.hh" 29 #include "hb-ot-shape-complex-arabic-private.hh" 30 #include "hb-ot-shape-private.hh" 31 32 33 /* buffer var allocations */ 34 #define arabic_shaping_action() complex_var_u8_0() /* arabic shaping action */ 35 36 #define HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH HB_BUFFER_SCRATCH_FLAG_COMPLEX0 37 38 /* See: 39 * https://github.com/harfbuzz/harfbuzz/commit/6e6f82b6f3dde0fc6c3c7d991d9ec6cfff57823d#commitcomment-14248516 */ 40 #define HB_ARABIC_GENERAL_CATEGORY_IS_WORD(gen_cat) \ 41 (FLAG_UNSAFE (gen_cat) & \ 42 (FLAG (HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED) | \ 43 FLAG (HB_UNICODE_GENERAL_CATEGORY_PRIVATE_USE) | \ 44 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) |*/ \ 45 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) | \ 46 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) | \ 47 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) |*/ \ 48 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) |*/ \ 49 FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \ 50 FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | \ 51 FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | \ 52 FLAG (HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER) | \ 53 FLAG (HB_UNICODE_GENERAL_CATEGORY_LETTER_NUMBER) | \ 54 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_NUMBER) | \ 55 FLAG (HB_UNICODE_GENERAL_CATEGORY_CURRENCY_SYMBOL) | \ 56 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_SYMBOL) | \ 57 FLAG (HB_UNICODE_GENERAL_CATEGORY_MATH_SYMBOL) | \ 58 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_SYMBOL))) 59 60 61 /* 62 * Joining types: 63 */ 64 65 /* 66 * Bits used in the joining tables 67 */ 68 enum hb_arabic_joining_type_t { 69 JOINING_TYPE_U = 0, 70 JOINING_TYPE_L = 1, 71 JOINING_TYPE_R = 2, 72 JOINING_TYPE_D = 3, 73 JOINING_TYPE_C = JOINING_TYPE_D, 74 JOINING_GROUP_ALAPH = 4, 75 JOINING_GROUP_DALATH_RISH = 5, 76 NUM_STATE_MACHINE_COLS = 6, 77 78 JOINING_TYPE_T = 7, 79 JOINING_TYPE_X = 8 /* means: use general-category to choose between U or T. */ 80 }; 81 82 #include "hb-ot-shape-complex-arabic-table.hh" 83 84 static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat) 85 { 86 unsigned int j_type = joining_type(u); 87 if (likely (j_type != JOINING_TYPE_X)) 88 return j_type; 89 90 return (FLAG_UNSAFE(gen_cat) & 91 (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | 92 FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | 93 FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT)) 94 ) ? JOINING_TYPE_T : JOINING_TYPE_U; 95 } 96 97 #define FEATURE_IS_SYRIAC(tag) hb_in_range<unsigned char> ((unsigned char) (tag), '2', '3') 98 99 static const hb_tag_t arabic_features[] = 100 { 101 HB_TAG('i','s','o','l'), 102 HB_TAG('f','i','n','a'), 103 HB_TAG('f','i','n','2'), 104 HB_TAG('f','i','n','3'), 105 HB_TAG('m','e','d','i'), 106 HB_TAG('m','e','d','2'), 107 HB_TAG('i','n','i','t'), 108 HB_TAG_NONE 109 }; 110 111 112 /* Same order as the feature array */ 113 enum arabic_action_t { 114 ISOL, 115 FINA, 116 FIN2, 117 FIN3, 118 MEDI, 119 MED2, 120 INIT, 121 122 NONE, 123 124 ARABIC_NUM_FEATURES = NONE, 125 126 /* We abuse the same byte for other things... */ 127 STCH_FIXED, 128 STCH_REPEATING, 129 }; 130 131 static const struct arabic_state_table_entry { 132 uint8_t prev_action; 133 uint8_t curr_action; 134 uint16_t next_state; 135 } arabic_state_table[][NUM_STATE_MACHINE_COLS] = 136 { 137 /* jt_U, jt_L, jt_R, jt_D, jg_ALAPH, jg_DALATH_RISH */ 138 139 /* State 0: prev was U, not willing to join. */ 140 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,6}, }, 141 142 /* State 1: prev was R or ISOL/ALAPH, not willing to join. */ 143 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN2,5}, {NONE,ISOL,6}, }, 144 145 /* State 2: prev was D/L in ISOL form, willing to join. */ 146 { {NONE,NONE,0}, {NONE,ISOL,2}, {INIT,FINA,1}, {INIT,FINA,3}, {INIT,FINA,4}, {INIT,FINA,6}, }, 147 148 /* State 3: prev was D in FINA form, willing to join. */ 149 { {NONE,NONE,0}, {NONE,ISOL,2}, {MEDI,FINA,1}, {MEDI,FINA,3}, {MEDI,FINA,4}, {MEDI,FINA,6}, }, 150 151 /* State 4: prev was FINA ALAPH, not willing to join. */ 152 { {NONE,NONE,0}, {NONE,ISOL,2}, {MED2,ISOL,1}, {MED2,ISOL,2}, {MED2,FIN2,5}, {MED2,ISOL,6}, }, 153 154 /* State 5: prev was FIN2/FIN3 ALAPH, not willing to join. */ 155 { {NONE,NONE,0}, {NONE,ISOL,2}, {ISOL,ISOL,1}, {ISOL,ISOL,2}, {ISOL,FIN2,5}, {ISOL,ISOL,6}, }, 156 157 /* State 6: prev was DALATH/RISH, not willing to join. */ 158 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN3,5}, {NONE,ISOL,6}, } 159 }; 160 161 162 static void 163 nuke_joiners (const hb_ot_shape_plan_t *plan, 164 hb_font_t *font, 165 hb_buffer_t *buffer); 166 167 static void 168 arabic_fallback_shape (const hb_ot_shape_plan_t *plan, 169 hb_font_t *font, 170 hb_buffer_t *buffer); 171 172 static void 173 record_stch (const hb_ot_shape_plan_t *plan, 174 hb_font_t *font, 175 hb_buffer_t *buffer); 176 177 static void 178 collect_features_arabic (hb_ot_shape_planner_t *plan) 179 { 180 hb_ot_map_builder_t *map = &plan->map; 181 182 /* We apply features according to the Arabic spec, with pauses 183 * in between most. 184 * 185 * The pause between init/medi/... and rlig is required. See eg: 186 * https://bugzilla.mozilla.org/show_bug.cgi?id=644184 187 * 188 * The pauses between init/medi/... themselves are not necessarily 189 * needed as only one of those features is applied to any character. 190 * The only difference it makes is when fonts have contextual 191 * substitutions. We now follow the order of the spec, which makes 192 * for better experience if that's what Uniscribe is doing. 193 * 194 * At least for Arabic, looks like Uniscribe has a pause between 195 * rlig and calt. Otherwise the IranNastaliq's ALLAH ligature won't 196 * work. However, testing shows that rlig and calt are applied 197 * together for Mongolian in Uniscribe. As such, we only add a 198 * pause for Arabic, not other scripts. 199 * 200 * A pause after calt is required to make KFGQPC Uthmanic Script HAFS 201 * work correctly. See https://github.com/harfbuzz/harfbuzz/issues/505 202 */ 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 (nullptr); 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 (nullptr); 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 /* No pause after rclt. See 98460779bae19e4d64d29461ff154b3527bf8420. */ 226 map->add_global_bool_feature (HB_TAG('r','c','l','t')); 227 map->add_global_bool_feature (HB_TAG('c','a','l','t')); 228 map->add_gsub_pause (nullptr); 229 230 /* The spec includes 'cswh'. Earlier versions of Windows 231 * used to enable this by default, but testing suggests 232 * that Windows 8 and later do not enable it by default, 233 * and spec now says 'Off by default'. 234 * We disabled this in ae23c24c32. 235 * Note that IranNastaliq uses this feature extensively 236 * to fixup broken glyph sequences. Oh well... 237 * Test case: U+0643,U+0640,U+0631. */ 238 //map->add_global_bool_feature (HB_TAG('c','s','w','h')); 239 map->add_global_bool_feature (HB_TAG('m','s','e','t')); 240 } 241 242 #include "hb-ot-shape-complex-arabic-fallback.hh" 243 244 struct arabic_shape_plan_t 245 { 246 ASSERT_POD (); 247 248 /* The "+ 1" in the next array is to accommodate for the "NONE" command, 249 * which is not an OpenType feature, but this simplifies the code by not 250 * having to do a "if (... < NONE) ..." and just rely on the fact that 251 * mask_array[NONE] == 0. */ 252 hb_mask_t mask_array[ARABIC_NUM_FEATURES + 1]; 253 254 arabic_fallback_plan_t *fallback_plan; 255 256 unsigned int do_fallback : 1; 257 unsigned int has_stch : 1; 258 }; 259 260 void * 261 data_create_arabic (const hb_ot_shape_plan_t *plan) 262 { 263 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t)); 264 if (unlikely (!arabic_plan)) 265 return nullptr; 266 267 arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC; 268 arabic_plan->has_stch = !!plan->map.get_1_mask (HB_TAG ('s','t','c','h')); 269 for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) { 270 arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]); 271 arabic_plan->do_fallback = arabic_plan->do_fallback && 272 (FEATURE_IS_SYRIAC (arabic_features[i]) || 273 plan->map.needs_fallback (arabic_features[i])); 274 } 275 276 return arabic_plan; 277 } 278 279 void 280 data_destroy_arabic (void *data) 281 { 282 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) data; 283 284 arabic_fallback_plan_destroy (arabic_plan->fallback_plan); 285 286 free (data); 287 } 288 289 static void 290 arabic_joining (hb_buffer_t *buffer) 291 { 292 unsigned int count = buffer->len; 293 hb_glyph_info_t *info = buffer->info; 294 unsigned int prev = (unsigned int) -1, state = 0; 295 296 /* Check pre-context */ 297 for (unsigned int i = 0; i < buffer->context_len[0]; i++) 298 { 299 unsigned int this_type = get_joining_type (buffer->context[0][i], buffer->unicode->general_category (buffer->context[0][i])); 300 301 if (unlikely (this_type == JOINING_TYPE_T)) 302 continue; 303 304 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; 305 state = entry->next_state; 306 break; 307 } 308 309 for (unsigned int i = 0; i < count; i++) 310 { 311 unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i])); 312 313 if (unlikely (this_type == JOINING_TYPE_T)) { 314 info[i].arabic_shaping_action() = NONE; 315 continue; 316 } 317 318 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; 319 320 if (entry->prev_action != NONE && prev != (unsigned int) -1) 321 { 322 info[prev].arabic_shaping_action() = entry->prev_action; 323 buffer->unsafe_to_break (prev, i + 1); 324 } 325 326 info[i].arabic_shaping_action() = entry->curr_action; 327 328 prev = i; 329 state = entry->next_state; 330 } 331 332 for (unsigned int i = 0; i < buffer->context_len[1]; i++) 333 { 334 unsigned int this_type = get_joining_type (buffer->context[1][i], buffer->unicode->general_category (buffer->context[1][i])); 335 336 if (unlikely (this_type == JOINING_TYPE_T)) 337 continue; 338 339 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; 340 if (entry->prev_action != NONE && prev != (unsigned int) -1) 341 info[prev].arabic_shaping_action() = entry->prev_action; 342 break; 343 } 344 } 345 346 static void 347 mongolian_variation_selectors (hb_buffer_t *buffer) 348 { 349 /* Copy arabic_shaping_action() from base to Mongolian variation selectors. */ 350 unsigned int count = buffer->len; 351 hb_glyph_info_t *info = buffer->info; 352 for (unsigned int i = 1; i < count; i++) 353 if (unlikely (hb_in_range<hb_codepoint_t> (info[i].codepoint, 0x180Bu, 0x180Du))) 354 info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action(); 355 } 356 357 void 358 setup_masks_arabic_plan (const arabic_shape_plan_t *arabic_plan, 359 hb_buffer_t *buffer, 360 hb_script_t script) 361 { 362 HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action); 363 364 arabic_joining (buffer); 365 if (script == HB_SCRIPT_MONGOLIAN) 366 mongolian_variation_selectors (buffer); 367 368 unsigned int count = buffer->len; 369 hb_glyph_info_t *info = buffer->info; 370 for (unsigned int i = 0; i < count; i++) 371 info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()]; 372 } 373 374 static void 375 setup_masks_arabic (const hb_ot_shape_plan_t *plan, 376 hb_buffer_t *buffer, 377 hb_font_t *font HB_UNUSED) 378 { 379 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; 380 setup_masks_arabic_plan (arabic_plan, buffer, plan->props.script); 381 } 382 383 384 static void 385 nuke_joiners (const hb_ot_shape_plan_t *plan HB_UNUSED, 386 hb_font_t *font HB_UNUSED, 387 hb_buffer_t *buffer) 388 { 389 unsigned int count = buffer->len; 390 hb_glyph_info_t *info = buffer->info; 391 for (unsigned int i = 0; i < count; i++) 392 if (_hb_glyph_info_is_zwj (&info[i])) 393 _hb_glyph_info_flip_joiners (&info[i]); 394 } 395 396 static void 397 arabic_fallback_shape (const hb_ot_shape_plan_t *plan, 398 hb_font_t *font, 399 hb_buffer_t *buffer) 400 { 401 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; 402 403 if (!arabic_plan->do_fallback) 404 return; 405 406 retry: 407 arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) hb_atomic_ptr_get (&arabic_plan->fallback_plan); 408 if (unlikely (!fallback_plan)) 409 { 410 /* This sucks. We need a font to build the fallback plan... */ 411 fallback_plan = arabic_fallback_plan_create (plan, font); 412 if (unlikely (!hb_atomic_ptr_cmpexch (&(const_cast<arabic_shape_plan_t *> (arabic_plan))->fallback_plan, nullptr, fallback_plan))) { 413 arabic_fallback_plan_destroy (fallback_plan); 414 goto retry; 415 } 416 } 417 418 arabic_fallback_plan_shape (fallback_plan, font, buffer); 419 } 420 421 /* 422 * Stretch feature: "stch". 423 * See example here: 424 * https://www.microsoft.com/typography/OpenTypeDev/syriac/intro.htm 425 * We implement this in a generic way, such that the Arabic subtending 426 * marks can use it as well. 427 */ 428 429 static void 430 record_stch (const hb_ot_shape_plan_t *plan, 431 hb_font_t *font, 432 hb_buffer_t *buffer) 433 { 434 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; 435 if (!arabic_plan->has_stch) 436 return; 437 438 /* 'stch' feature was just applied. Look for anything that multiplied, 439 * and record it for stch treatment later. Note that rtlm, frac, etc 440 * are applied before stch, but we assume that they didn't result in 441 * anything multiplying into 5 pieces, so it's safe-ish... */ 442 443 unsigned int count = buffer->len; 444 hb_glyph_info_t *info = buffer->info; 445 for (unsigned int i = 0; i < count; i++) 446 if (unlikely (_hb_glyph_info_multiplied (&info[i]))) 447 { 448 unsigned int comp = _hb_glyph_info_get_lig_comp (&info[i]); 449 info[i].arabic_shaping_action() = comp % 2 ? STCH_REPEATING : STCH_FIXED; 450 buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH; 451 } 452 } 453 454 static void 455 apply_stch (const hb_ot_shape_plan_t *plan, 456 hb_buffer_t *buffer, 457 hb_font_t *font) 458 { 459 if (likely (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH))) 460 return; 461 462 /* The Arabic shaper currently always processes in RTL mode, so we should 463 * stretch / position the stretched pieces to the left / preceding glyphs. */ 464 465 /* We do a two pass implementation: 466 * First pass calculates the exact number of extra glyphs we need, 467 * We then enlarge buffer to have that much room, 468 * Second pass applies the stretch, copying things to the end of buffer. 469 */ 470 471 int sign = font->x_scale < 0 ? -1 : +1; 472 unsigned int extra_glyphs_needed = 0; // Set during MEASURE, used during CUT 473 typedef enum { MEASURE, CUT } step_t; 474 475 for (step_t step = MEASURE; step <= CUT; step = (step_t) (step + 1)) 476 { 477 unsigned int count = buffer->len; 478 hb_glyph_info_t *info = buffer->info; 479 hb_glyph_position_t *pos = buffer->pos; 480 unsigned int new_len = count + extra_glyphs_needed; // write head during CUT 481 unsigned int j = new_len; 482 for (unsigned int i = count; i; i--) 483 { 484 if (!hb_in_range<unsigned> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING)) 485 { 486 if (step == CUT) 487 { 488 --j; 489 info[j] = info[i - 1]; 490 pos[j] = pos[i - 1]; 491 } 492 continue; 493 } 494 495 /* Yay, justification! */ 496 497 hb_position_t w_total = 0; // Total to be filled 498 hb_position_t w_fixed = 0; // Sum of fixed tiles 499 hb_position_t w_repeating = 0; // Sum of repeating tiles 500 int n_fixed = 0; 501 int n_repeating = 0; 502 503 unsigned int end = i; 504 while (i && 505 hb_in_range<unsigned> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING)) 506 { 507 i--; 508 hb_position_t width = font->get_glyph_h_advance (info[i].codepoint); 509 if (info[i].arabic_shaping_action() == STCH_FIXED) 510 { 511 w_fixed += width; 512 n_fixed++; 513 } 514 else 515 { 516 w_repeating += width; 517 n_repeating++; 518 } 519 } 520 unsigned int start = i; 521 unsigned int context = i; 522 while (context && 523 !hb_in_range<unsigned> (info[context - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING) && 524 (_hb_glyph_info_is_default_ignorable (&info[context - 1]) || 525 HB_ARABIC_GENERAL_CATEGORY_IS_WORD (_hb_glyph_info_get_general_category (&info[context - 1])))) 526 { 527 context--; 528 w_total += pos[context].x_advance; 529 } 530 i++; // Don't touch i again. 531 532 DEBUG_MSG (ARABIC, nullptr, "%s stretch at (%d,%d,%d)", 533 step == MEASURE ? "measuring" : "cutting", context, start, end); 534 DEBUG_MSG (ARABIC, nullptr, "rest of word: count=%d width %d", start - context, w_total); 535 DEBUG_MSG (ARABIC, nullptr, "fixed tiles: count=%d width=%d", n_fixed, w_fixed); 536 DEBUG_MSG (ARABIC, nullptr, "repeating tiles: count=%d width=%d", n_repeating, w_repeating); 537 538 /* Number of additional times to repeat each repeating tile. */ 539 int n_copies = 0; 540 541 hb_position_t w_remaining = w_total - w_fixed; 542 if (sign * w_remaining > sign * w_repeating && sign * w_repeating > 0) 543 n_copies = (sign * w_remaining) / (sign * w_repeating) - 1; 544 545 /* See if we can improve the fit by adding an extra repeat and squeezing them together a bit. */ 546 hb_position_t extra_repeat_overlap = 0; 547 hb_position_t shortfall = sign * w_remaining - sign * w_repeating * (n_copies + 1); 548 if (shortfall > 0 && n_repeating > 0) 549 { 550 ++n_copies; 551 hb_position_t excess = (n_copies + 1) * sign * w_repeating - sign * w_remaining; 552 if (excess > 0) 553 extra_repeat_overlap = excess / (n_copies * n_repeating); 554 } 555 556 if (step == MEASURE) 557 { 558 extra_glyphs_needed += n_copies * n_repeating; 559 DEBUG_MSG (ARABIC, nullptr, "will add extra %d copies of repeating tiles", n_copies); 560 } 561 else 562 { 563 buffer->unsafe_to_break (context, end); 564 hb_position_t x_offset = 0; 565 for (unsigned int k = end; k > start; k--) 566 { 567 hb_position_t width = font->get_glyph_h_advance (info[k - 1].codepoint); 568 569 unsigned int repeat = 1; 570 if (info[k - 1].arabic_shaping_action() == STCH_REPEATING) 571 repeat += n_copies; 572 573 DEBUG_MSG (ARABIC, nullptr, "appending %d copies of glyph %d; j=%d", 574 repeat, info[k - 1].codepoint, j); 575 for (unsigned int n = 0; n < repeat; n++) 576 { 577 x_offset -= width; 578 if (n > 0) 579 x_offset += extra_repeat_overlap; 580 pos[k - 1].x_offset = x_offset; 581 /* Append copy. */ 582 --j; 583 info[j] = info[k - 1]; 584 pos[j] = pos[k - 1]; 585 } 586 } 587 } 588 } 589 590 if (step == MEASURE) 591 { 592 if (unlikely (!buffer->ensure (count + extra_glyphs_needed))) 593 break; 594 } 595 else 596 { 597 assert (j == 0); 598 buffer->len = new_len; 599 } 600 } 601 } 602 603 604 static void 605 postprocess_glyphs_arabic (const hb_ot_shape_plan_t *plan, 606 hb_buffer_t *buffer, 607 hb_font_t *font) 608 { 609 apply_stch (plan, buffer, font); 610 611 HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action); 612 } 613 614 /* http://www.unicode.org/reports/tr53/tr53-1.pdf */ 615 616 static hb_codepoint_t 617 modifier_combining_marks[] = 618 { 619 0x0654u, /* ARABIC HAMZA ABOVE */ 620 0x0655u, /* ARABIC HAMZA BELOW */ 621 0x0658u, /* ARABIC MARK NOON GHUNNA */ 622 0x06DCu, /* ARABIC SMALL HIGH SEEN */ 623 0x06E3u, /* ARABIC SMALL LOW SEEN */ 624 0x06E7u, /* ARABIC SMALL HIGH YEH */ 625 0x06E8u, /* ARABIC SMALL HIGH NOON */ 626 0x08F3u, /* ARABIC SMALL HIGH WAW */ 627 }; 628 629 static inline bool 630 info_is_mcm (const hb_glyph_info_t &info) 631 { 632 hb_codepoint_t u = info.codepoint; 633 for (unsigned int i = 0; i < ARRAY_LENGTH (modifier_combining_marks); i++) 634 if (u == modifier_combining_marks[i]) 635 return true; 636 return false; 637 } 638 639 static void 640 reorder_marks_arabic (const hb_ot_shape_plan_t *plan, 641 hb_buffer_t *buffer, 642 unsigned int start, 643 unsigned int end) 644 { 645 hb_glyph_info_t *info = buffer->info; 646 647 unsigned int i = start; 648 for (unsigned int cc = 220; cc <= 230; cc += 10) 649 { 650 DEBUG_MSG (ARABIC, buffer, "Looking for %d's starting at %d\n", cc, i); 651 while (i < end && info_cc(info[i]) < cc) 652 i++; 653 DEBUG_MSG (ARABIC, buffer, "Looking for %d's stopped at %d\n", cc, i); 654 655 if (i == end) 656 break; 657 658 if (info_cc(info[i]) > cc) 659 continue; 660 661 /* Technically we should also check "info_cc(info[j]) == cc" 662 * in the following loop. But not doing it is safe; we might 663 * end up moving all the 220 MCMs and 230 MCMs together in one 664 * move and be done. */ 665 unsigned int j = i; 666 while (j < end && info_is_mcm (info[j])) 667 j++; 668 DEBUG_MSG (ARABIC, buffer, "Found %d's from %d to %d\n", cc, i, j); 669 670 if (i == j) 671 continue; 672 673 /* Shift it! */ 674 DEBUG_MSG (ARABIC, buffer, "Shifting %d's: %d %d\n", cc, i, j); 675 hb_glyph_info_t temp[HB_OT_SHAPE_COMPLEX_MAX_COMBINING_MARKS]; 676 assert (j - i <= ARRAY_LENGTH (temp)); 677 buffer->merge_clusters (start, j); 678 memmove (temp, &info[i], (j - i) * sizeof (hb_glyph_info_t)); 679 memmove (&info[start + j - i], &info[start], (i - start) * sizeof (hb_glyph_info_t)); 680 memmove (&info[start], temp, (j - i) * sizeof (hb_glyph_info_t)); 681 682 start += j - i; 683 684 i = j; 685 } 686 } 687 688 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic = 689 { 690 collect_features_arabic, 691 nullptr, /* override_features */ 692 data_create_arabic, 693 data_destroy_arabic, 694 nullptr, /* preprocess_text */ 695 postprocess_glyphs_arabic, 696 HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT, 697 nullptr, /* decompose */ 698 nullptr, /* compose */ 699 setup_masks_arabic, 700 nullptr, /* disable_otl */ 701 reorder_marks_arabic, 702 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, 703 true, /* fallback_position */ 704 }; 705
