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.hh" 28 29 #ifndef HB_NO_OT_SHAPE 30 31 #include "hb-ot-shape-complex-arabic.hh" 32 #include "hb-ot-shape.hh" 33 34 35 /* buffer var allocations */ 36 #define arabic_shaping_action() complex_var_u8_0() /* arabic shaping action */ 37 38 #define HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH HB_BUFFER_SCRATCH_FLAG_COMPLEX0 39 40 /* See: 41 * https://github.com/harfbuzz/harfbuzz/commit/6e6f82b6f3dde0fc6c3c7d991d9ec6cfff57823d#commitcomment-14248516 */ 42 #define HB_ARABIC_GENERAL_CATEGORY_IS_WORD(gen_cat) \ 43 (FLAG_UNSAFE (gen_cat) & \ 44 (FLAG (HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED) | \ 45 FLAG (HB_UNICODE_GENERAL_CATEGORY_PRIVATE_USE) | \ 46 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) |*/ \ 47 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) | \ 48 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) | \ 49 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) |*/ \ 50 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) |*/ \ 51 FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \ 52 FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | \ 53 FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | \ 54 FLAG (HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER) | \ 55 FLAG (HB_UNICODE_GENERAL_CATEGORY_LETTER_NUMBER) | \ 56 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_NUMBER) | \ 57 FLAG (HB_UNICODE_GENERAL_CATEGORY_CURRENCY_SYMBOL) | \ 58 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_SYMBOL) | \ 59 FLAG (HB_UNICODE_GENERAL_CATEGORY_MATH_SYMBOL) | \ 60 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_SYMBOL))) 61 62 63 /* 64 * Joining types: 65 */ 66 67 /* 68 * Bits used in the joining tables 69 */ 70 enum hb_arabic_joining_type_t { 71 JOINING_TYPE_U = 0, 72 JOINING_TYPE_L = 1, 73 JOINING_TYPE_R = 2, 74 JOINING_TYPE_D = 3, 75 JOINING_TYPE_C = JOINING_TYPE_D, 76 JOINING_GROUP_ALAPH = 4, 77 JOINING_GROUP_DALATH_RISH = 5, 78 NUM_STATE_MACHINE_COLS = 6, 79 80 JOINING_TYPE_T = 7, 81 JOINING_TYPE_X = 8 /* means: use general-category to choose between U or T. */ 82 }; 83 84 #include "hb-ot-shape-complex-arabic-table.hh" 85 get_joining_type(hb_codepoint_t u,hb_unicode_general_category_t gen_cat)86 static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat) 87 { 88 unsigned int j_type = joining_type(u); 89 if (likely (j_type != JOINING_TYPE_X)) 90 return j_type; 91 92 return (FLAG_UNSAFE(gen_cat) & 93 (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | 94 FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | 95 FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT)) 96 ) ? JOINING_TYPE_T : JOINING_TYPE_U; 97 } 98 99 #define FEATURE_IS_SYRIAC(tag) hb_in_range<unsigned char> ((unsigned char) (tag), '2', '3') 100 101 static const hb_tag_t arabic_features[] = 102 { 103 HB_TAG('i','s','o','l'), 104 HB_TAG('f','i','n','a'), 105 HB_TAG('f','i','n','2'), 106 HB_TAG('f','i','n','3'), 107 HB_TAG('m','e','d','i'), 108 HB_TAG('m','e','d','2'), 109 HB_TAG('i','n','i','t'), 110 HB_TAG_NONE 111 }; 112 113 114 /* Same order as the feature array */ 115 enum arabic_action_t { 116 ISOL, 117 FINA, 118 FIN2, 119 FIN3, 120 MEDI, 121 MED2, 122 INIT, 123 124 NONE, 125 126 ARABIC_NUM_FEATURES = NONE, 127 128 /* We abuse the same byte for other things... */ 129 STCH_FIXED, 130 STCH_REPEATING, 131 }; 132 133 static const struct arabic_state_table_entry { 134 uint8_t prev_action; 135 uint8_t curr_action; 136 uint16_t next_state; 137 } arabic_state_table[][NUM_STATE_MACHINE_COLS] = 138 { 139 /* jt_U, jt_L, jt_R, jt_D, jg_ALAPH, jg_DALATH_RISH */ 140 141 /* State 0: prev was U, not willing to join. */ 142 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,6}, }, 143 144 /* State 1: prev was R or ISOL/ALAPH, not willing to join. */ 145 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN2,5}, {NONE,ISOL,6}, }, 146 147 /* State 2: prev was D/L in ISOL form, willing to join. */ 148 { {NONE,NONE,0}, {NONE,ISOL,2}, {INIT,FINA,1}, {INIT,FINA,3}, {INIT,FINA,4}, {INIT,FINA,6}, }, 149 150 /* State 3: prev was D in FINA form, willing to join. */ 151 { {NONE,NONE,0}, {NONE,ISOL,2}, {MEDI,FINA,1}, {MEDI,FINA,3}, {MEDI,FINA,4}, {MEDI,FINA,6}, }, 152 153 /* State 4: prev was FINA ALAPH, not willing to join. */ 154 { {NONE,NONE,0}, {NONE,ISOL,2}, {MED2,ISOL,1}, {MED2,ISOL,2}, {MED2,FIN2,5}, {MED2,ISOL,6}, }, 155 156 /* State 5: prev was FIN2/FIN3 ALAPH, not willing to join. */ 157 { {NONE,NONE,0}, {NONE,ISOL,2}, {ISOL,ISOL,1}, {ISOL,ISOL,2}, {ISOL,FIN2,5}, {ISOL,ISOL,6}, }, 158 159 /* State 6: prev was DALATH/RISH, not willing to join. */ 160 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN3,5}, {NONE,ISOL,6}, } 161 }; 162 163 164 static void 165 arabic_fallback_shape (const hb_ot_shape_plan_t *plan, 166 hb_font_t *font, 167 hb_buffer_t *buffer); 168 169 static void 170 record_stch (const hb_ot_shape_plan_t *plan, 171 hb_font_t *font, 172 hb_buffer_t *buffer); 173 174 static void collect_features_arabic(hb_ot_shape_planner_t * plan)175 collect_features_arabic (hb_ot_shape_planner_t *plan) 176 { 177 hb_ot_map_builder_t *map = &plan->map; 178 179 /* We apply features according to the Arabic spec, with pauses 180 * in between most. 181 * 182 * The pause between init/medi/... and rlig is required. See eg: 183 * https://bugzilla.mozilla.org/show_bug.cgi?id=644184 184 * 185 * The pauses between init/medi/... themselves are not necessarily 186 * needed as only one of those features is applied to any character. 187 * The only difference it makes is when fonts have contextual 188 * substitutions. We now follow the order of the spec, which makes 189 * for better experience if that's what Uniscribe is doing. 190 * 191 * At least for Arabic, looks like Uniscribe has a pause between 192 * rlig and calt. Otherwise the IranNastaliq's ALLAH ligature won't 193 * work. However, testing shows that rlig and calt are applied 194 * together for Mongolian in Uniscribe. As such, we only add a 195 * pause for Arabic, not other scripts. 196 * 197 * A pause after calt is required to make KFGQPC Uthmanic Script HAFS 198 * work correctly. See https://github.com/harfbuzz/harfbuzz/issues/505 199 */ 200 201 202 map->enable_feature (HB_TAG('s','t','c','h')); 203 map->add_gsub_pause (record_stch); 204 205 map->enable_feature (HB_TAG('c','c','m','p')); 206 map->enable_feature (HB_TAG('l','o','c','l')); 207 208 map->add_gsub_pause (nullptr); 209 210 for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) 211 { 212 bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]); 213 map->add_feature (arabic_features[i], has_fallback ? F_HAS_FALLBACK : F_NONE); 214 map->add_gsub_pause (nullptr); 215 } 216 217 /* Normally, Unicode says a ZWNJ means "don't ligate". In Arabic script 218 * however, it says a ZWJ should also mean "don't ligate". So we run 219 * the main ligating features as MANUAL_ZWJ. */ 220 221 map->enable_feature (HB_TAG('r','l','i','g'), F_MANUAL_ZWJ | F_HAS_FALLBACK); 222 223 if (plan->props.script == HB_SCRIPT_ARABIC) 224 map->add_gsub_pause (arabic_fallback_shape); 225 226 /* No pause after rclt. See 98460779bae19e4d64d29461ff154b3527bf8420. */ 227 map->enable_feature (HB_TAG('r','c','l','t'), F_MANUAL_ZWJ); 228 map->enable_feature (HB_TAG('c','a','l','t'), F_MANUAL_ZWJ); 229 map->add_gsub_pause (nullptr); 230 231 /* And undo here. */ 232 233 /* The spec includes 'cswh'. Earlier versions of Windows 234 * used to enable this by default, but testing suggests 235 * that Windows 8 and later do not enable it by default, 236 * and spec now says 'Off by default'. 237 * We disabled this in ae23c24c32. 238 * Note that IranNastaliq uses this feature extensively 239 * to fixup broken glyph sequences. Oh well... 240 * Test case: U+0643,U+0640,U+0631. */ 241 //map->enable_feature (HB_TAG('c','s','w','h')); 242 map->enable_feature (HB_TAG('m','s','e','t')); 243 } 244 245 #include "hb-ot-shape-complex-arabic-fallback.hh" 246 247 struct arabic_shape_plan_t 248 { 249 /* The "+ 1" in the next array is to accommodate for the "NONE" command, 250 * which is not an OpenType feature, but this simplifies the code by not 251 * having to do a "if (... < NONE) ..." and just rely on the fact that 252 * mask_array[NONE] == 0. */ 253 hb_mask_t mask_array[ARABIC_NUM_FEATURES + 1]; 254 255 hb_atomic_ptr_t<arabic_fallback_plan_t> fallback_plan; 256 257 unsigned int do_fallback : 1; 258 unsigned int has_stch : 1; 259 }; 260 261 void * data_create_arabic(const hb_ot_shape_plan_t * plan)262 data_create_arabic (const hb_ot_shape_plan_t *plan) 263 { 264 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t)); 265 if (unlikely (!arabic_plan)) 266 return nullptr; 267 268 arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC; 269 arabic_plan->has_stch = !!plan->map.get_1_mask (HB_TAG ('s','t','c','h')); 270 for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) { 271 arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]); 272 arabic_plan->do_fallback = arabic_plan->do_fallback && 273 (FEATURE_IS_SYRIAC (arabic_features[i]) || 274 plan->map.needs_fallback (arabic_features[i])); 275 } 276 277 return arabic_plan; 278 } 279 280 void data_destroy_arabic(void * data)281 data_destroy_arabic (void *data) 282 { 283 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) data; 284 285 arabic_fallback_plan_destroy (arabic_plan->fallback_plan); 286 287 free (data); 288 } 289 290 static void arabic_joining(hb_buffer_t * buffer)291 arabic_joining (hb_buffer_t *buffer) 292 { 293 unsigned int count = buffer->len; 294 hb_glyph_info_t *info = buffer->info; 295 unsigned int prev = (unsigned int) -1, state = 0; 296 297 /* Check pre-context */ 298 for (unsigned int i = 0; i < buffer->context_len[0]; i++) 299 { 300 unsigned int this_type = get_joining_type (buffer->context[0][i], buffer->unicode->general_category (buffer->context[0][i])); 301 302 if (unlikely (this_type == JOINING_TYPE_T)) 303 continue; 304 305 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; 306 state = entry->next_state; 307 break; 308 } 309 310 for (unsigned int i = 0; i < count; i++) 311 { 312 unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i])); 313 314 if (unlikely (this_type == JOINING_TYPE_T)) { 315 info[i].arabic_shaping_action() = NONE; 316 continue; 317 } 318 319 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; 320 321 if (entry->prev_action != NONE && prev != (unsigned int) -1) 322 { 323 info[prev].arabic_shaping_action() = entry->prev_action; 324 buffer->unsafe_to_break (prev, i + 1); 325 } 326 327 info[i].arabic_shaping_action() = entry->curr_action; 328 329 prev = i; 330 state = entry->next_state; 331 } 332 333 for (unsigned int i = 0; i < buffer->context_len[1]; i++) 334 { 335 unsigned int this_type = get_joining_type (buffer->context[1][i], buffer->unicode->general_category (buffer->context[1][i])); 336 337 if (unlikely (this_type == JOINING_TYPE_T)) 338 continue; 339 340 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; 341 if (entry->prev_action != NONE && prev != (unsigned int) -1) 342 info[prev].arabic_shaping_action() = entry->prev_action; 343 break; 344 } 345 } 346 347 static void mongolian_variation_selectors(hb_buffer_t * buffer)348 mongolian_variation_selectors (hb_buffer_t *buffer) 349 { 350 /* Copy arabic_shaping_action() from base to Mongolian variation selectors. */ 351 unsigned int count = buffer->len; 352 hb_glyph_info_t *info = buffer->info; 353 for (unsigned int i = 1; i < count; i++) 354 if (unlikely (hb_in_range<hb_codepoint_t> (info[i].codepoint, 0x180Bu, 0x180Du))) 355 info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action(); 356 } 357 358 void setup_masks_arabic_plan(const arabic_shape_plan_t * arabic_plan,hb_buffer_t * buffer,hb_script_t script)359 setup_masks_arabic_plan (const arabic_shape_plan_t *arabic_plan, 360 hb_buffer_t *buffer, 361 hb_script_t script) 362 { 363 HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action); 364 365 arabic_joining (buffer); 366 if (script == HB_SCRIPT_MONGOLIAN) 367 mongolian_variation_selectors (buffer); 368 369 unsigned int count = buffer->len; 370 hb_glyph_info_t *info = buffer->info; 371 for (unsigned int i = 0; i < count; i++) 372 info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()]; 373 } 374 375 static void setup_masks_arabic(const hb_ot_shape_plan_t * plan,hb_buffer_t * buffer,hb_font_t * font HB_UNUSED)376 setup_masks_arabic (const hb_ot_shape_plan_t *plan, 377 hb_buffer_t *buffer, 378 hb_font_t *font HB_UNUSED) 379 { 380 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; 381 setup_masks_arabic_plan (arabic_plan, buffer, plan->props.script); 382 } 383 384 static void arabic_fallback_shape(const hb_ot_shape_plan_t * plan,hb_font_t * font,hb_buffer_t * buffer)385 arabic_fallback_shape (const hb_ot_shape_plan_t *plan, 386 hb_font_t *font, 387 hb_buffer_t *buffer) 388 { 389 #ifdef HB_NO_OT_SHAPE_COMPLEX_ARABIC_FALLBACK 390 return; 391 #endif 392 393 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; 394 395 if (!arabic_plan->do_fallback) 396 return; 397 398 retry: 399 arabic_fallback_plan_t *fallback_plan = arabic_plan->fallback_plan; 400 if (unlikely (!fallback_plan)) 401 { 402 /* This sucks. We need a font to build the fallback plan... */ 403 fallback_plan = arabic_fallback_plan_create (plan, font); 404 if (unlikely (!arabic_plan->fallback_plan.cmpexch (nullptr, fallback_plan))) 405 { 406 arabic_fallback_plan_destroy (fallback_plan); 407 goto retry; 408 } 409 } 410 411 arabic_fallback_plan_shape (fallback_plan, font, buffer); 412 } 413 414 /* 415 * Stretch feature: "stch". 416 * See example here: 417 * https://docs.microsoft.com/en-us/typography/script-development/syriac 418 * We implement this in a generic way, such that the Arabic subtending 419 * marks can use it as well. 420 */ 421 422 static void record_stch(const hb_ot_shape_plan_t * plan,hb_font_t * font HB_UNUSED,hb_buffer_t * buffer)423 record_stch (const hb_ot_shape_plan_t *plan, 424 hb_font_t *font HB_UNUSED, 425 hb_buffer_t *buffer) 426 { 427 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; 428 if (!arabic_plan->has_stch) 429 return; 430 431 /* 'stch' feature was just applied. Look for anything that multiplied, 432 * and record it for stch treatment later. Note that rtlm, frac, etc 433 * are applied before stch, but we assume that they didn't result in 434 * anything multiplying into 5 pieces, so it's safe-ish... */ 435 436 unsigned int count = buffer->len; 437 hb_glyph_info_t *info = buffer->info; 438 for (unsigned int i = 0; i < count; i++) 439 if (unlikely (_hb_glyph_info_multiplied (&info[i]))) 440 { 441 unsigned int comp = _hb_glyph_info_get_lig_comp (&info[i]); 442 info[i].arabic_shaping_action() = comp % 2 ? STCH_REPEATING : STCH_FIXED; 443 buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH; 444 } 445 } 446 447 static void apply_stch(const hb_ot_shape_plan_t * plan HB_UNUSED,hb_buffer_t * buffer,hb_font_t * font)448 apply_stch (const hb_ot_shape_plan_t *plan HB_UNUSED, 449 hb_buffer_t *buffer, 450 hb_font_t *font) 451 { 452 if (likely (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH))) 453 return; 454 455 /* The Arabic shaper currently always processes in RTL mode, so we should 456 * stretch / position the stretched pieces to the left / preceding glyphs. */ 457 458 /* We do a two pass implementation: 459 * First pass calculates the exact number of extra glyphs we need, 460 * We then enlarge buffer to have that much room, 461 * Second pass applies the stretch, copying things to the end of buffer. 462 */ 463 464 int sign = font->x_scale < 0 ? -1 : +1; 465 unsigned int extra_glyphs_needed = 0; // Set during MEASURE, used during CUT 466 enum { MEASURE, CUT } /* step_t */; 467 468 for (unsigned int step = MEASURE; step <= CUT; step = step + 1) 469 { 470 unsigned int count = buffer->len; 471 hb_glyph_info_t *info = buffer->info; 472 hb_glyph_position_t *pos = buffer->pos; 473 unsigned int new_len = count + extra_glyphs_needed; // write head during CUT 474 unsigned int j = new_len; 475 for (unsigned int i = count; i; i--) 476 { 477 if (!hb_in_range<uint8_t> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING)) 478 { 479 if (step == CUT) 480 { 481 --j; 482 info[j] = info[i - 1]; 483 pos[j] = pos[i - 1]; 484 } 485 continue; 486 } 487 488 /* Yay, justification! */ 489 490 hb_position_t w_total = 0; // Total to be filled 491 hb_position_t w_fixed = 0; // Sum of fixed tiles 492 hb_position_t w_repeating = 0; // Sum of repeating tiles 493 int n_fixed = 0; 494 int n_repeating = 0; 495 496 unsigned int end = i; 497 while (i && 498 hb_in_range<uint8_t> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING)) 499 { 500 i--; 501 hb_position_t width = font->get_glyph_h_advance (info[i].codepoint); 502 if (info[i].arabic_shaping_action() == STCH_FIXED) 503 { 504 w_fixed += width; 505 n_fixed++; 506 } 507 else 508 { 509 w_repeating += width; 510 n_repeating++; 511 } 512 } 513 unsigned int start = i; 514 unsigned int context = i; 515 while (context && 516 !hb_in_range<uint8_t> (info[context - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING) && 517 (_hb_glyph_info_is_default_ignorable (&info[context - 1]) || 518 HB_ARABIC_GENERAL_CATEGORY_IS_WORD (_hb_glyph_info_get_general_category (&info[context - 1])))) 519 { 520 context--; 521 w_total += pos[context].x_advance; 522 } 523 i++; // Don't touch i again. 524 525 DEBUG_MSG (ARABIC, nullptr, "%s stretch at (%d,%d,%d)", 526 step == MEASURE ? "measuring" : "cutting", context, start, end); 527 DEBUG_MSG (ARABIC, nullptr, "rest of word: count=%d width %d", start - context, w_total); 528 DEBUG_MSG (ARABIC, nullptr, "fixed tiles: count=%d width=%d", n_fixed, w_fixed); 529 DEBUG_MSG (ARABIC, nullptr, "repeating tiles: count=%d width=%d", n_repeating, w_repeating); 530 531 /* Number of additional times to repeat each repeating tile. */ 532 int n_copies = 0; 533 534 hb_position_t w_remaining = w_total - w_fixed; 535 if (sign * w_remaining > sign * w_repeating && sign * w_repeating > 0) 536 n_copies = (sign * w_remaining) / (sign * w_repeating) - 1; 537 538 /* See if we can improve the fit by adding an extra repeat and squeezing them together a bit. */ 539 hb_position_t extra_repeat_overlap = 0; 540 hb_position_t shortfall = sign * w_remaining - sign * w_repeating * (n_copies + 1); 541 if (shortfall > 0 && n_repeating > 0) 542 { 543 ++n_copies; 544 hb_position_t excess = (n_copies + 1) * sign * w_repeating - sign * w_remaining; 545 if (excess > 0) 546 extra_repeat_overlap = excess / (n_copies * n_repeating); 547 } 548 549 if (step == MEASURE) 550 { 551 extra_glyphs_needed += n_copies * n_repeating; 552 DEBUG_MSG (ARABIC, nullptr, "will add extra %d copies of repeating tiles", n_copies); 553 } 554 else 555 { 556 buffer->unsafe_to_break (context, end); 557 hb_position_t x_offset = 0; 558 for (unsigned int k = end; k > start; k--) 559 { 560 hb_position_t width = font->get_glyph_h_advance (info[k - 1].codepoint); 561 562 unsigned int repeat = 1; 563 if (info[k - 1].arabic_shaping_action() == STCH_REPEATING) 564 repeat += n_copies; 565 566 DEBUG_MSG (ARABIC, nullptr, "appending %d copies of glyph %d; j=%d", 567 repeat, info[k - 1].codepoint, j); 568 for (unsigned int n = 0; n < repeat; n++) 569 { 570 x_offset -= width; 571 if (n > 0) 572 x_offset += extra_repeat_overlap; 573 pos[k - 1].x_offset = x_offset; 574 /* Append copy. */ 575 --j; 576 info[j] = info[k - 1]; 577 pos[j] = pos[k - 1]; 578 } 579 } 580 } 581 } 582 583 if (step == MEASURE) 584 { 585 if (unlikely (!buffer->ensure (count + extra_glyphs_needed))) 586 break; 587 } 588 else 589 { 590 assert (j == 0); 591 buffer->len = new_len; 592 } 593 } 594 } 595 596 597 static void postprocess_glyphs_arabic(const hb_ot_shape_plan_t * plan,hb_buffer_t * buffer,hb_font_t * font)598 postprocess_glyphs_arabic (const hb_ot_shape_plan_t *plan, 599 hb_buffer_t *buffer, 600 hb_font_t *font) 601 { 602 apply_stch (plan, buffer, font); 603 604 HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action); 605 } 606 607 /* http://www.unicode.org/reports/tr53/ */ 608 609 static hb_codepoint_t 610 modifier_combining_marks[] = 611 { 612 0x0654u, /* ARABIC HAMZA ABOVE */ 613 0x0655u, /* ARABIC HAMZA BELOW */ 614 0x0658u, /* ARABIC MARK NOON GHUNNA */ 615 0x06DCu, /* ARABIC SMALL HIGH SEEN */ 616 0x06E3u, /* ARABIC SMALL LOW SEEN */ 617 0x06E7u, /* ARABIC SMALL HIGH YEH */ 618 0x06E8u, /* ARABIC SMALL HIGH NOON */ 619 0x08D3u, /* ARABIC SMALL LOW WAW */ 620 0x08F3u, /* ARABIC SMALL HIGH WAW */ 621 }; 622 623 static inline bool info_is_mcm(const hb_glyph_info_t & info)624 info_is_mcm (const hb_glyph_info_t &info) 625 { 626 hb_codepoint_t u = info.codepoint; 627 for (unsigned int i = 0; i < ARRAY_LENGTH (modifier_combining_marks); i++) 628 if (u == modifier_combining_marks[i]) 629 return true; 630 return false; 631 } 632 633 static void reorder_marks_arabic(const hb_ot_shape_plan_t * plan HB_UNUSED,hb_buffer_t * buffer,unsigned int start,unsigned int end)634 reorder_marks_arabic (const hb_ot_shape_plan_t *plan HB_UNUSED, 635 hb_buffer_t *buffer, 636 unsigned int start, 637 unsigned int end) 638 { 639 hb_glyph_info_t *info = buffer->info; 640 641 DEBUG_MSG (ARABIC, buffer, "Reordering marks from %d to %d", start, end); 642 643 unsigned int i = start; 644 for (unsigned int cc = 220; cc <= 230; cc += 10) 645 { 646 DEBUG_MSG (ARABIC, buffer, "Looking for %d's starting at %d", cc, i); 647 while (i < end && info_cc(info[i]) < cc) 648 i++; 649 DEBUG_MSG (ARABIC, buffer, "Looking for %d's stopped at %d", cc, i); 650 651 if (i == end) 652 break; 653 654 if (info_cc(info[i]) > cc) 655 continue; 656 657 unsigned int j = i; 658 while (j < end && info_cc(info[j]) == cc && info_is_mcm (info[j])) 659 j++; 660 661 if (i == j) 662 continue; 663 664 DEBUG_MSG (ARABIC, buffer, "Found %d's from %d to %d", cc, i, j); 665 666 /* Shift it! */ 667 DEBUG_MSG (ARABIC, buffer, "Shifting %d's: %d %d", cc, i, j); 668 hb_glyph_info_t temp[HB_OT_SHAPE_COMPLEX_MAX_COMBINING_MARKS]; 669 assert (j - i <= ARRAY_LENGTH (temp)); 670 buffer->merge_clusters (start, j); 671 memmove (temp, &info[i], (j - i) * sizeof (hb_glyph_info_t)); 672 memmove (&info[start + j - i], &info[start], (i - start) * sizeof (hb_glyph_info_t)); 673 memmove (&info[start], temp, (j - i) * sizeof (hb_glyph_info_t)); 674 675 /* Renumber CC such that the reordered sequence is still sorted. 676 * 22 and 26 are chosen because they are smaller than all Arabic categories, 677 * and are folded back to 220/230 respectively during fallback mark positioning. 678 * 679 * We do this because the CGJ-handling logic in the normalizer relies on 680 * mark sequences having an increasing order even after this reordering. 681 * https://github.com/harfbuzz/harfbuzz/issues/554 682 * This, however, does break some obscure sequences, where the normalizer 683 * might compose a sequence that it should not. For example, in the seequence 684 * ALEF, HAMZAH, MADDAH, we should NOT try to compose ALEF+MADDAH, but with this 685 * renumbering, we will. 686 */ 687 unsigned int new_start = start + j - i; 688 unsigned int new_cc = cc == 220 ? HB_MODIFIED_COMBINING_CLASS_CCC22 : HB_MODIFIED_COMBINING_CLASS_CCC26; 689 while (start < new_start) 690 { 691 _hb_glyph_info_set_modified_combining_class (&info[start], new_cc); 692 start++; 693 } 694 695 i = j; 696 } 697 } 698 699 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic = 700 { 701 collect_features_arabic, 702 nullptr, /* override_features */ 703 data_create_arabic, 704 data_destroy_arabic, 705 nullptr, /* preprocess_text */ 706 postprocess_glyphs_arabic, 707 HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT, 708 nullptr, /* decompose */ 709 nullptr, /* compose */ 710 setup_masks_arabic, 711 HB_TAG_NONE, /* gpos_tag */ 712 reorder_marks_arabic, 713 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, 714 true, /* fallback_position */ 715 }; 716 717 718 #endif 719