1 /* 2 * Copyright 2011,2012 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-indic-private.hh" 28 #include "hb-ot-layout-private.hh" 29 30 /* buffer var allocations */ 31 #define indic_category() complex_var_u8_0() /* indic_category_t */ 32 #define indic_position() complex_var_u8_1() /* indic_position_t */ 33 34 35 /* 36 * Indic shaper. 37 */ 38 39 40 #define IN_HALF_BLOCK(u, Base) (((u) & ~0x7F) == (Base)) 41 42 #define IS_DEVA(u) (IN_HALF_BLOCK (u, 0x0900)) 43 #define IS_BENG(u) (IN_HALF_BLOCK (u, 0x0980)) 44 #define IS_GURU(u) (IN_HALF_BLOCK (u, 0x0A00)) 45 #define IS_GUJR(u) (IN_HALF_BLOCK (u, 0x0A80)) 46 #define IS_ORYA(u) (IN_HALF_BLOCK (u, 0x0B00)) 47 #define IS_TAML(u) (IN_HALF_BLOCK (u, 0x0B80)) 48 #define IS_TELU(u) (IN_HALF_BLOCK (u, 0x0C00)) 49 #define IS_KNDA(u) (IN_HALF_BLOCK (u, 0x0C80)) 50 #define IS_MLYM(u) (IN_HALF_BLOCK (u, 0x0D00)) 51 #define IS_SINH(u) (IN_HALF_BLOCK (u, 0x0D80)) 52 #define IS_KHMR(u) (IN_HALF_BLOCK (u, 0x1780)) 53 54 55 #define MATRA_POS_LEFT(u) POS_PRE_M 56 #define MATRA_POS_RIGHT(u) ( \ 57 IS_DEVA(u) ? POS_AFTER_SUB : \ 58 IS_BENG(u) ? POS_AFTER_POST : \ 59 IS_GURU(u) ? POS_AFTER_POST : \ 60 IS_GUJR(u) ? POS_AFTER_POST : \ 61 IS_ORYA(u) ? POS_AFTER_POST : \ 62 IS_TAML(u) ? POS_AFTER_POST : \ 63 IS_TELU(u) ? (u <= 0x0C42 ? POS_BEFORE_SUB : POS_AFTER_SUB) : \ 64 IS_KNDA(u) ? (u < 0x0CC3 || u > 0xCD6 ? POS_BEFORE_SUB : POS_AFTER_SUB) : \ 65 IS_MLYM(u) ? POS_AFTER_POST : \ 66 IS_SINH(u) ? POS_AFTER_SUB : \ 67 IS_KHMR(u) ? POS_AFTER_POST : \ 68 /*default*/ POS_AFTER_SUB \ 69 ) 70 #define MATRA_POS_TOP(u) ( /* BENG and MLYM don't have top matras. */ \ 71 IS_DEVA(u) ? POS_AFTER_SUB : \ 72 IS_GURU(u) ? POS_AFTER_POST : /* Deviate from spec */ \ 73 IS_GUJR(u) ? POS_AFTER_SUB : \ 74 IS_ORYA(u) ? POS_AFTER_MAIN : \ 75 IS_TAML(u) ? POS_AFTER_SUB : \ 76 IS_TELU(u) ? POS_BEFORE_SUB : \ 77 IS_KNDA(u) ? POS_BEFORE_SUB : \ 78 IS_SINH(u) ? POS_AFTER_SUB : \ 79 IS_KHMR(u) ? POS_AFTER_POST : \ 80 /*default*/ POS_AFTER_SUB \ 81 ) 82 #define MATRA_POS_BOTTOM(u) ( \ 83 IS_DEVA(u) ? POS_AFTER_SUB : \ 84 IS_BENG(u) ? POS_AFTER_SUB : \ 85 IS_GURU(u) ? POS_AFTER_POST : \ 86 IS_GUJR(u) ? POS_AFTER_POST : \ 87 IS_ORYA(u) ? POS_AFTER_SUB : \ 88 IS_TAML(u) ? POS_AFTER_POST : \ 89 IS_TELU(u) ? POS_BEFORE_SUB : \ 90 IS_KNDA(u) ? POS_BEFORE_SUB : \ 91 IS_MLYM(u) ? POS_AFTER_POST : \ 92 IS_SINH(u) ? POS_AFTER_SUB : \ 93 IS_KHMR(u) ? POS_AFTER_POST : \ 94 /*default*/ POS_AFTER_SUB \ 95 ) 96 97 static inline indic_position_t 98 matra_position (hb_codepoint_t u, indic_position_t side) 99 { 100 switch ((int) side) 101 { 102 case POS_PRE_C: return MATRA_POS_LEFT (u); 103 case POS_POST_C: return MATRA_POS_RIGHT (u); 104 case POS_ABOVE_C: return MATRA_POS_TOP (u); 105 case POS_BELOW_C: return MATRA_POS_BOTTOM (u); 106 }; 107 return side; 108 } 109 110 /* XXX 111 * This is a hack for now. We should move this data into the main Indic table. 112 * Or completely remove it and just check in the tables. 113 */ 114 static const hb_codepoint_t ra_chars[] = { 115 0x0930, /* Devanagari */ 116 0x09B0, /* Bengali */ 117 0x09F0, /* Bengali */ 118 0x0A30, /* Gurmukhi */ /* No Reph */ 119 0x0AB0, /* Gujarati */ 120 0x0B30, /* Oriya */ 121 0x0BB0, /* Tamil */ /* No Reph */ 122 0x0C30, /* Telugu */ /* Reph formed only with ZWJ */ 123 0x0CB0, /* Kannada */ 124 0x0D30, /* Malayalam */ /* No Reph, Logical Repha */ 125 126 0x0DBB, /* Sinhala */ /* Reph formed only with ZWJ */ 127 128 0x179A, /* Khmer */ /* No Reph, Visual Repha */ 129 }; 130 131 static inline indic_position_t 132 consonant_position (hb_codepoint_t u) 133 { 134 if ((u & ~0x007F) == 0x1780) 135 return POS_BELOW_C; /* In Khmer coeng model, post and below forms should not be reordered. */ 136 return POS_BASE_C; /* Will recategorize later based on font lookups. */ 137 } 138 139 static inline bool 140 is_ra (hb_codepoint_t u) 141 { 142 for (unsigned int i = 0; i < ARRAY_LENGTH (ra_chars); i++) 143 if (u == ra_chars[i]) 144 return true; 145 return false; 146 } 147 148 static inline bool 149 is_one_of (const hb_glyph_info_t &info, unsigned int flags) 150 { 151 /* If it ligated, all bets are off. */ 152 if (is_a_ligature (info)) return false; 153 return !!(FLAG (info.indic_category()) & flags); 154 } 155 156 #define JOINER_FLAGS (FLAG (OT_ZWJ) | FLAG (OT_ZWNJ)) 157 static inline bool 158 is_joiner (const hb_glyph_info_t &info) 159 { 160 return is_one_of (info, JOINER_FLAGS); 161 } 162 163 /* Note: 164 * 165 * We treat Vowels and placeholders as if they were consonants. This is safe because Vowels 166 * cannot happen in a consonant syllable. The plus side however is, we can call the 167 * consonant syllable logic from the vowel syllable function and get it all right! */ 168 #define CONSONANT_FLAGS (FLAG (OT_C) | FLAG (OT_CM) | FLAG (OT_Ra) | FLAG (OT_V) | FLAG (OT_NBSP) | FLAG (OT_DOTTEDCIRCLE)) 169 static inline bool 170 is_consonant (const hb_glyph_info_t &info) 171 { 172 return is_one_of (info, CONSONANT_FLAGS); 173 } 174 175 #define HALANT_OR_COENG_FLAGS (FLAG (OT_H) | FLAG (OT_Coeng)) 176 static inline bool 177 is_halant_or_coeng (const hb_glyph_info_t &info) 178 { 179 return is_one_of (info, HALANT_OR_COENG_FLAGS); 180 } 181 182 static inline void 183 set_indic_properties (hb_glyph_info_t &info) 184 { 185 hb_codepoint_t u = info.codepoint; 186 unsigned int type = hb_indic_get_categories (u); 187 indic_category_t cat = (indic_category_t) (type & 0x7F); 188 indic_position_t pos = (indic_position_t) (type >> 8); 189 190 191 /* 192 * Re-assign category 193 */ 194 195 196 /* The spec says U+0952 is OT_A. However, testing shows that Uniscribe 197 * treats U+0951..U+0952 all as OT_VD. 198 * TESTS: 199 * U+092E,U+0947,U+0952 200 * U+092E,U+0952,U+0947 201 * U+092E,U+0947,U+0951 202 * U+092E,U+0951,U+0947 203 * */ 204 if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x0951, 0x0954))) 205 cat = OT_VD; 206 207 if (unlikely (u == 0x17D1)) 208 cat = OT_X; 209 if (cat == OT_X && 210 unlikely (hb_in_range<hb_codepoint_t> (u, 0x17CB, 0x17D3))) /* Khmer Various signs */ 211 { 212 /* These are like Top Matras. */ 213 cat = OT_M; 214 pos = POS_ABOVE_C; 215 } 216 if (u == 0x17C6) /* Khmer Bindu doesn't like to be repositioned. */ 217 cat = OT_N; 218 219 if (unlikely (u == 0x17D2)) cat = OT_Coeng; /* Khmer coeng */ 220 else if (unlikely (u == 0x200C)) cat = OT_ZWNJ; 221 else if (unlikely (u == 0x200D)) cat = OT_ZWJ; 222 else if (unlikely (u == 0x25CC)) cat = OT_DOTTEDCIRCLE; 223 else if (unlikely (u == 0x0A71)) cat = OT_SM; /* GURMUKHI ADDAK. More like consonant medial. like 0A75. */ 224 225 if (cat == OT_Repha) { 226 /* There are two kinds of characters marked as Repha: 227 * - The ones that are GenCat=Mn are already positioned visually, ie. after base. (eg. Khmer) 228 * - The ones that are GenCat=Lo is encoded logically, ie. beginning of syllable. (eg. Malayalam) 229 * 230 * We recategorize the first kind to look like a Nukta and attached to the base directly. 231 */ 232 if (_hb_glyph_info_get_general_category (&info) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) 233 cat = OT_N; 234 } 235 236 237 238 /* 239 * Re-assign position. 240 */ 241 242 if ((FLAG (cat) & CONSONANT_FLAGS)) 243 { 244 pos = consonant_position (u); 245 if (is_ra (u)) 246 cat = OT_Ra; 247 } 248 else if (cat == OT_M) 249 { 250 pos = matra_position (u, pos); 251 } 252 else if (cat == OT_SM || cat == OT_VD) 253 { 254 pos = POS_SMVD; 255 } 256 257 if (unlikely (u == 0x0B01)) pos = POS_BEFORE_SUB; /* Oriya Bindu is BeforeSub in the spec. */ 258 259 260 261 info.indic_category() = cat; 262 info.indic_position() = pos; 263 } 264 265 /* 266 * Things above this line should ideally be moved to the Indic table itself. 267 */ 268 269 270 /* 271 * Indic configurations. Note that we do not want to keep every single script-specific 272 * behavior in these tables necessarily. This should mainly be used for per-script 273 * properties that are cheaper keeping here, than in the code. Ie. if, say, one and 274 * only one script has an exception, that one script can be if'ed directly in the code, 275 * instead of adding a new flag in these structs. 276 */ 277 278 enum base_position_t { 279 BASE_POS_FIRST, 280 BASE_POS_LAST 281 }; 282 enum reph_position_t { 283 REPH_POS_DEFAULT = POS_BEFORE_POST, 284 285 REPH_POS_AFTER_MAIN = POS_AFTER_MAIN, 286 REPH_POS_BEFORE_SUB = POS_BEFORE_SUB, 287 REPH_POS_AFTER_SUB = POS_AFTER_SUB, 288 REPH_POS_BEFORE_POST = POS_BEFORE_POST, 289 REPH_POS_AFTER_POST = POS_AFTER_POST 290 }; 291 enum reph_mode_t { 292 REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */ 293 REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */ 294 REPH_MODE_VIS_REPHA, /* Encoded Repha character, no reordering needed. */ 295 REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */ 296 }; 297 struct indic_config_t 298 { 299 hb_script_t script; 300 bool has_old_spec; 301 hb_codepoint_t virama; 302 base_position_t base_pos; 303 reph_position_t reph_pos; 304 reph_mode_t reph_mode; 305 }; 306 307 static const indic_config_t indic_configs[] = 308 { 309 /* Default. Should be first. */ 310 {HB_SCRIPT_INVALID, false, 0,BASE_POS_LAST, REPH_POS_DEFAULT, REPH_MODE_IMPLICIT}, 311 {HB_SCRIPT_DEVANAGARI,true, 0x094D,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT}, 312 {HB_SCRIPT_BENGALI, true, 0x09CD,BASE_POS_LAST, REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT}, 313 {HB_SCRIPT_GURMUKHI, true, 0x0A4D,BASE_POS_LAST, REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT}, 314 {HB_SCRIPT_GUJARATI, true, 0x0ACD,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT}, 315 {HB_SCRIPT_ORIYA, true, 0x0B4D,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT}, 316 {HB_SCRIPT_TAMIL, true, 0x0BCD,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT}, 317 {HB_SCRIPT_TELUGU, true, 0x0C4D,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT}, 318 {HB_SCRIPT_KANNADA, true, 0x0CCD,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT}, 319 {HB_SCRIPT_MALAYALAM, true, 0x0D4D,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA}, 320 {HB_SCRIPT_SINHALA, false,0x0DCA,BASE_POS_FIRST,REPH_POS_AFTER_MAIN, REPH_MODE_EXPLICIT}, 321 {HB_SCRIPT_KHMER, false,0x17D2,BASE_POS_FIRST,REPH_POS_DEFAULT, REPH_MODE_VIS_REPHA}, 322 }; 323 324 325 326 /* 327 * Indic shaper. 328 */ 329 330 struct feature_list_t { 331 hb_tag_t tag; 332 hb_ot_map_feature_flags_t flags; 333 }; 334 335 static const feature_list_t 336 indic_features[] = 337 { 338 /* 339 * Basic features. 340 * These features are applied in order, one at a time, after initial_reordering. 341 */ 342 {HB_TAG('n','u','k','t'), F_GLOBAL}, 343 {HB_TAG('a','k','h','n'), F_GLOBAL}, 344 {HB_TAG('r','p','h','f'), F_NONE}, 345 {HB_TAG('r','k','r','f'), F_GLOBAL}, 346 {HB_TAG('p','r','e','f'), F_NONE}, 347 {HB_TAG('b','l','w','f'), F_NONE}, 348 {HB_TAG('h','a','l','f'), F_NONE}, 349 {HB_TAG('a','b','v','f'), F_NONE}, 350 {HB_TAG('p','s','t','f'), F_NONE}, 351 {HB_TAG('c','f','a','r'), F_NONE}, 352 {HB_TAG('v','a','t','u'), F_GLOBAL}, 353 {HB_TAG('c','j','c','t'), F_GLOBAL}, 354 /* 355 * Other features. 356 * These features are applied all at once, after final_reordering. 357 */ 358 {HB_TAG('i','n','i','t'), F_NONE}, 359 {HB_TAG('p','r','e','s'), F_GLOBAL}, 360 {HB_TAG('a','b','v','s'), F_GLOBAL}, 361 {HB_TAG('b','l','w','s'), F_GLOBAL}, 362 {HB_TAG('p','s','t','s'), F_GLOBAL}, 363 {HB_TAG('h','a','l','n'), F_GLOBAL}, 364 /* Positioning features, though we don't care about the types. */ 365 {HB_TAG('d','i','s','t'), F_GLOBAL}, 366 {HB_TAG('a','b','v','m'), F_GLOBAL}, 367 {HB_TAG('b','l','w','m'), F_GLOBAL}, 368 }; 369 370 /* 371 * Must be in the same order as the indic_features array. 372 */ 373 enum { 374 _NUKT, 375 _AKHN, 376 RPHF, 377 _RKRF, 378 PREF, 379 BLWF, 380 HALF, 381 ABVF, 382 PSTF, 383 CFAR, 384 _VATU, 385 _CJCT, 386 387 INIT, 388 _PRES, 389 _ABVS, 390 _BLWS, 391 _PSTS, 392 _HALN, 393 _DIST, 394 _ABVM, 395 _BLWM, 396 397 INDIC_NUM_FEATURES, 398 INDIC_BASIC_FEATURES = INIT /* Don't forget to update this! */ 399 }; 400 401 static void 402 setup_syllables (const hb_ot_shape_plan_t *plan, 403 hb_font_t *font, 404 hb_buffer_t *buffer); 405 static void 406 initial_reordering (const hb_ot_shape_plan_t *plan, 407 hb_font_t *font, 408 hb_buffer_t *buffer); 409 static void 410 final_reordering (const hb_ot_shape_plan_t *plan, 411 hb_font_t *font, 412 hb_buffer_t *buffer); 413 414 static void 415 collect_features_indic (hb_ot_shape_planner_t *plan) 416 { 417 hb_ot_map_builder_t *map = &plan->map; 418 419 /* Do this before any lookups have been applied. */ 420 map->add_gsub_pause (setup_syllables); 421 422 map->add_global_bool_feature (HB_TAG('l','o','c','l')); 423 /* The Indic specs do not require ccmp, but we apply it here since if 424 * there is a use of it, it's typically at the beginning. */ 425 map->add_global_bool_feature (HB_TAG('c','c','m','p')); 426 427 428 unsigned int i = 0; 429 map->add_gsub_pause (initial_reordering); 430 for (; i < INDIC_BASIC_FEATURES; i++) { 431 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ); 432 map->add_gsub_pause (NULL); 433 } 434 map->add_gsub_pause (final_reordering); 435 for (; i < INDIC_NUM_FEATURES; i++) { 436 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ); 437 } 438 } 439 440 static void 441 override_features_indic (hb_ot_shape_planner_t *plan) 442 { 443 /* Uniscribe does not apply 'kern'. */ 444 if (hb_options ().uniscribe_bug_compatible) 445 plan->map.add_feature (HB_TAG('k','e','r','n'), 0, F_GLOBAL); 446 447 plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL); 448 } 449 450 451 struct would_substitute_feature_t 452 { 453 inline void init (const hb_ot_map_t *map, hb_tag_t feature_tag) 454 { 455 map->get_stage_lookups (0/*GSUB*/, 456 map->get_feature_stage (0/*GSUB*/, feature_tag), 457 &lookups, &count); 458 } 459 460 inline bool would_substitute (const hb_codepoint_t *glyphs, 461 unsigned int glyphs_count, 462 bool zero_context, 463 hb_face_t *face) const 464 { 465 for (unsigned int i = 0; i < count; i++) 466 if (hb_ot_layout_lookup_would_substitute_fast (face, lookups[i].index, glyphs, glyphs_count, zero_context)) 467 return true; 468 return false; 469 } 470 471 private: 472 const hb_ot_map_t::lookup_map_t *lookups; 473 unsigned int count; 474 }; 475 476 struct indic_shape_plan_t 477 { 478 ASSERT_POD (); 479 480 inline bool get_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const 481 { 482 hb_codepoint_t glyph = virama_glyph; 483 if (unlikely (virama_glyph == (hb_codepoint_t) -1)) 484 { 485 if (!config->virama || !font->get_glyph (config->virama, 0, &glyph)) 486 glyph = 0; 487 /* Technically speaking, the spec says we should apply 'locl' to virama too. 488 * Maybe one day... */ 489 490 /* Our get_glyph() function needs a font, so we can't get the virama glyph 491 * during shape planning... Instead, overwrite it here. It's safe. Don't worry! */ 492 (const_cast<indic_shape_plan_t *> (this))->virama_glyph = glyph; 493 } 494 495 *pglyph = glyph; 496 return glyph != 0; 497 } 498 499 const indic_config_t *config; 500 501 bool is_old_spec; 502 hb_codepoint_t virama_glyph; 503 504 would_substitute_feature_t rphf; 505 would_substitute_feature_t pref; 506 would_substitute_feature_t blwf; 507 would_substitute_feature_t pstf; 508 509 hb_mask_t mask_array[INDIC_NUM_FEATURES]; 510 }; 511 512 static void * 513 data_create_indic (const hb_ot_shape_plan_t *plan) 514 { 515 indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (1, sizeof (indic_shape_plan_t)); 516 if (unlikely (!indic_plan)) 517 return NULL; 518 519 indic_plan->config = &indic_configs[0]; 520 for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++) 521 if (plan->props.script == indic_configs[i].script) { 522 indic_plan->config = &indic_configs[i]; 523 break; 524 } 525 526 indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FF) != '2'); 527 indic_plan->virama_glyph = (hb_codepoint_t) -1; 528 529 indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f')); 530 indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f')); 531 indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f')); 532 indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f')); 533 534 for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++) 535 indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ? 536 0 : plan->map.get_1_mask (indic_features[i].tag); 537 538 return indic_plan; 539 } 540 541 static void 542 data_destroy_indic (void *data) 543 { 544 free (data); 545 } 546 547 static indic_position_t 548 consonant_position_from_face (const indic_shape_plan_t *indic_plan, 549 const hb_codepoint_t glyphs[2], 550 hb_face_t *face) 551 { 552 /* For old-spec, the order of glyphs is Consonant,Virama, 553 * whereas for new-spec, it's Virama,Consonant. However, 554 * some broken fonts (like Free Sans) simply copied lookups 555 * from old-spec to new-spec without modification. 556 * And oddly enough, Uniscribe seems to respect those lookups. 557 * Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds 558 * base at 0. The font however, only has lookups matching 559 * 930,94D in 'blwf', not the expected 94D,930 (with new-spec 560 * table). As such, we simply match both sequences. Seems 561 * to work. */ 562 bool zero_context = indic_plan->is_old_spec ? false : true; 563 hb_codepoint_t glyphs_r[2] = {glyphs[1], glyphs[0]}; 564 if (indic_plan->pref.would_substitute (glyphs , 2, zero_context, face) || 565 indic_plan->pref.would_substitute (glyphs_r, 2, zero_context, face)) 566 return POS_POST_C; 567 if (indic_plan->blwf.would_substitute (glyphs , 2, zero_context, face) || 568 indic_plan->blwf.would_substitute (glyphs_r, 2, zero_context, face)) 569 return POS_BELOW_C; 570 if (indic_plan->pstf.would_substitute (glyphs , 2, zero_context, face) || 571 indic_plan->pstf.would_substitute (glyphs_r, 2, zero_context, face)) 572 return POS_POST_C; 573 return POS_BASE_C; 574 } 575 576 577 enum syllable_type_t { 578 consonant_syllable, 579 vowel_syllable, 580 standalone_cluster, 581 broken_cluster, 582 non_indic_cluster, 583 }; 584 585 #include "hb-ot-shape-complex-indic-machine.hh" 586 587 588 static void 589 setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED, 590 hb_buffer_t *buffer, 591 hb_font_t *font HB_UNUSED) 592 { 593 HB_BUFFER_ALLOCATE_VAR (buffer, indic_category); 594 HB_BUFFER_ALLOCATE_VAR (buffer, indic_position); 595 596 /* We cannot setup masks here. We save information about characters 597 * and setup masks later on in a pause-callback. */ 598 599 unsigned int count = buffer->len; 600 for (unsigned int i = 0; i < count; i++) 601 set_indic_properties (buffer->info[i]); 602 } 603 604 static void 605 setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED, 606 hb_font_t *font HB_UNUSED, 607 hb_buffer_t *buffer) 608 { 609 find_syllables (buffer); 610 } 611 612 static int 613 compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb) 614 { 615 int a = pa->indic_position(); 616 int b = pb->indic_position(); 617 618 return a < b ? -1 : a == b ? 0 : +1; 619 } 620 621 622 623 static void 624 update_consonant_positions (const hb_ot_shape_plan_t *plan, 625 hb_font_t *font, 626 hb_buffer_t *buffer) 627 { 628 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; 629 630 hb_codepoint_t glyphs[2]; 631 if (indic_plan->get_virama_glyph (font, &glyphs[0])) 632 { 633 hb_face_t *face = font->face; 634 unsigned int count = buffer->len; 635 for (unsigned int i = 0; i < count; i++) 636 if (buffer->info[i].indic_position() == POS_BASE_C) { 637 glyphs[1] = buffer->info[i].codepoint; 638 buffer->info[i].indic_position() = consonant_position_from_face (indic_plan, glyphs, face); 639 } 640 } 641 } 642 643 644 /* Rules from: 645 * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */ 646 647 static void 648 initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan, 649 hb_face_t *face, 650 hb_buffer_t *buffer, 651 unsigned int start, unsigned int end) 652 { 653 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; 654 hb_glyph_info_t *info = buffer->info; 655 656 657 /* 1. Find base consonant: 658 * 659 * The shaping engine finds the base consonant of the syllable, using the 660 * following algorithm: starting from the end of the syllable, move backwards 661 * until a consonant is found that does not have a below-base or post-base 662 * form (post-base forms have to follow below-base forms), or that is not a 663 * pre-base reordering Ra, or arrive at the first consonant. The consonant 664 * stopped at will be the base. 665 * 666 * o If the syllable starts with Ra + Halant (in a script that has Reph) 667 * and has more than one consonant, Ra is excluded from candidates for 668 * base consonants. 669 */ 670 671 unsigned int base = end; 672 bool has_reph = false; 673 674 { 675 /* -> If the syllable starts with Ra + Halant (in a script that has Reph) 676 * and has more than one consonant, Ra is excluded from candidates for 677 * base consonants. */ 678 unsigned int limit = start; 679 if (indic_plan->mask_array[RPHF] && 680 start + 3 <= end && 681 ( 682 (indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info[start + 2])) || 683 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == OT_ZWJ) 684 )) 685 { 686 /* See if it matches the 'rphf' feature. */ 687 hb_codepoint_t glyphs[2] = {info[start].codepoint, info[start + 1].codepoint}; 688 if (indic_plan->rphf.would_substitute (glyphs, ARRAY_LENGTH (glyphs), true, face)) 689 { 690 limit += 2; 691 while (limit < end && is_joiner (info[limit])) 692 limit++; 693 base = start; 694 has_reph = true; 695 } 696 } else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == OT_Repha) 697 { 698 limit += 1; 699 while (limit < end && is_joiner (info[limit])) 700 limit++; 701 base = start; 702 has_reph = true; 703 } 704 705 switch (indic_plan->config->base_pos) 706 { 707 default: 708 assert (false); 709 /* fallthrough */ 710 711 case BASE_POS_LAST: 712 { 713 /* -> starting from the end of the syllable, move backwards */ 714 unsigned int i = end; 715 bool seen_below = false; 716 do { 717 i--; 718 /* -> until a consonant is found */ 719 if (is_consonant (info[i])) 720 { 721 /* -> that does not have a below-base or post-base form 722 * (post-base forms have to follow below-base forms), */ 723 if (info[i].indic_position() != POS_BELOW_C && 724 (info[i].indic_position() != POS_POST_C || seen_below)) 725 { 726 base = i; 727 break; 728 } 729 if (info[i].indic_position() == POS_BELOW_C) 730 seen_below = true; 731 732 /* -> or that is not a pre-base reordering Ra, 733 * 734 * IMPLEMENTATION NOTES: 735 * 736 * Our pre-base reordering Ra's are marked POS_POST_C, so will be skipped 737 * by the logic above already. 738 */ 739 740 /* -> or arrive at the first consonant. The consonant stopped at will 741 * be the base. */ 742 base = i; 743 } 744 else 745 { 746 /* A ZWJ after a Halant stops the base search, and requests an explicit 747 * half form. 748 * A ZWJ before a Halant, requests a subjoined form instead, and hence 749 * search continues. This is particularly important for Bengali 750 * sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */ 751 if (start < i && 752 info[i].indic_category() == OT_ZWJ && 753 info[i - 1].indic_category() == OT_H) 754 break; 755 } 756 } while (i > limit); 757 } 758 break; 759 760 case BASE_POS_FIRST: 761 { 762 /* In scripts without half forms (eg. Khmer), the first consonant is always the base. */ 763 764 if (!has_reph) 765 base = limit; 766 767 /* Find the last base consonant that is not blocked by ZWJ. If there is 768 * a ZWJ right before a base consonant, that would request a subjoined form. */ 769 for (unsigned int i = limit; i < end; i++) 770 if (is_consonant (info[i]) && info[i].indic_position() == POS_BASE_C) 771 { 772 if (limit < i && info[i - 1].indic_category() == OT_ZWJ) 773 break; 774 else 775 base = i; 776 } 777 778 /* Mark all subsequent consonants as below. */ 779 for (unsigned int i = base + 1; i < end; i++) 780 if (is_consonant (info[i]) && info[i].indic_position() == POS_BASE_C) 781 info[i].indic_position() = POS_BELOW_C; 782 } 783 break; 784 } 785 786 /* -> If the syllable starts with Ra + Halant (in a script that has Reph) 787 * and has more than one consonant, Ra is excluded from candidates for 788 * base consonants. 789 * 790 * Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */ 791 if (has_reph && base == start && limit - base <= 2) { 792 /* Have no other consonant, so Reph is not formed and Ra becomes base. */ 793 has_reph = false; 794 } 795 } 796 797 798 /* 2. Decompose and reorder Matras: 799 * 800 * Each matra and any syllable modifier sign in the cluster are moved to the 801 * appropriate position relative to the consonant(s) in the cluster. The 802 * shaping engine decomposes two- or three-part matras into their constituent 803 * parts before any repositioning. Matra characters are classified by which 804 * consonant in a conjunct they have affinity for and are reordered to the 805 * following positions: 806 * 807 * o Before first half form in the syllable 808 * o After subjoined consonants 809 * o After post-form consonant 810 * o After main consonant (for above marks) 811 * 812 * IMPLEMENTATION NOTES: 813 * 814 * The normalize() routine has already decomposed matras for us, so we don't 815 * need to worry about that. 816 */ 817 818 819 /* 3. Reorder marks to canonical order: 820 * 821 * Adjacent nukta and halant or nukta and vedic sign are always repositioned 822 * if necessary, so that the nukta is first. 823 * 824 * IMPLEMENTATION NOTES: 825 * 826 * We don't need to do this: the normalize() routine already did this for us. 827 */ 828 829 830 /* Reorder characters */ 831 832 for (unsigned int i = start; i < base; i++) 833 info[i].indic_position() = MIN (POS_PRE_C, (indic_position_t) info[i].indic_position()); 834 835 if (base < end) 836 info[base].indic_position() = POS_BASE_C; 837 838 /* Mark final consonants. A final consonant is one appearing after a matra, 839 * like in Khmer. */ 840 for (unsigned int i = base + 1; i < end; i++) 841 if (info[i].indic_category() == OT_M) { 842 for (unsigned int j = i + 1; j < end; j++) 843 if (is_consonant (info[j])) { 844 info[j].indic_position() = POS_FINAL_C; 845 break; 846 } 847 break; 848 } 849 850 /* Handle beginning Ra */ 851 if (has_reph) 852 info[start].indic_position() = POS_RA_TO_BECOME_REPH; 853 854 /* For old-style Indic script tags, move the first post-base Halant after 855 * last consonant. Only do this if there is *not* a Halant after last 856 * consonant. Otherwise it becomes messy. */ 857 if (indic_plan->is_old_spec) { 858 for (unsigned int i = base + 1; i < end; i++) 859 if (info[i].indic_category() == OT_H) { 860 unsigned int j; 861 for (j = end - 1; j > i; j--) 862 if (is_consonant (info[j]) || info[j].indic_category() == OT_H) 863 break; 864 if (info[j].indic_category() != OT_H && j > i) { 865 /* Move Halant to after last consonant. */ 866 hb_glyph_info_t t = info[i]; 867 memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0])); 868 info[j] = t; 869 } 870 break; 871 } 872 } 873 874 /* Attach misc marks to previous char to move with them. */ 875 { 876 indic_position_t last_pos = POS_START; 877 for (unsigned int i = start; i < end; i++) 878 { 879 if ((FLAG (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | HALANT_OR_COENG_FLAGS))) 880 { 881 info[i].indic_position() = last_pos; 882 if (unlikely (info[i].indic_category() == OT_H && 883 info[i].indic_position() == POS_PRE_M)) 884 { 885 /* 886 * Uniscribe doesn't move the Halant with Left Matra. 887 * TEST: U+092B,U+093F,U+094DE 888 * We follow. This is important for the Sinhala 889 * U+0DDA split matra since it decomposes to U+0DD9,U+0DCA 890 * where U+0DD9 is a left matra and U+0DCA is the virama. 891 * We don't want to move the virama with the left matra. 892 * TEST: U+0D9A,U+0DDA 893 */ 894 for (unsigned int j = i; j > start; j--) 895 if (info[j - 1].indic_position() != POS_PRE_M) { 896 info[i].indic_position() = info[j - 1].indic_position(); 897 break; 898 } 899 } 900 } else if (info[i].indic_position() != POS_SMVD) { 901 last_pos = (indic_position_t) info[i].indic_position(); 902 } 903 } 904 } 905 /* Re-attach ZWJ, ZWNJ, and halant to next char, for after-base consonants. */ 906 { 907 unsigned int last_halant = end; 908 for (unsigned int i = base + 1; i < end; i++) 909 if (is_halant_or_coeng (info[i])) 910 last_halant = i; 911 else if (is_consonant (info[i])) { 912 for (unsigned int j = last_halant; j < i; j++) 913 if (info[j].indic_position() != POS_SMVD) 914 info[j].indic_position() = info[i].indic_position(); 915 } 916 } 917 918 { 919 /* Things are out-of-control for post base positions, they may shuffle 920 * around like crazy, so merge clusters. For pre-base stuff, we handle 921 * cluster issues in final reordering. */ 922 buffer->merge_clusters (base, end); 923 /* Sit tight, rock 'n roll! */ 924 hb_bubble_sort (info + start, end - start, compare_indic_order); 925 /* Find base again */ 926 base = end; 927 for (unsigned int i = start; i < end; i++) 928 if (info[i].indic_position() == POS_BASE_C) { 929 base = i; 930 break; 931 } 932 } 933 934 /* Setup masks now */ 935 936 { 937 hb_mask_t mask; 938 939 /* Reph */ 940 for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++) 941 info[i].mask |= indic_plan->mask_array[RPHF]; 942 943 /* Pre-base */ 944 mask = indic_plan->mask_array[HALF]; 945 for (unsigned int i = start; i < base; i++) 946 info[i].mask |= mask; 947 /* Base */ 948 mask = 0; 949 if (base < end) 950 info[base].mask |= mask; 951 /* Post-base */ 952 mask = indic_plan->mask_array[BLWF] | indic_plan->mask_array[ABVF] | indic_plan->mask_array[PSTF]; 953 for (unsigned int i = base + 1; i < end; i++) 954 info[i].mask |= mask; 955 } 956 957 if (indic_plan->is_old_spec && 958 buffer->props.script == HB_SCRIPT_DEVANAGARI) 959 { 960 /* Old-spec eye-lash Ra needs special handling. From the 961 * spec: 962 * 963 * "The feature 'below-base form' is applied to consonants 964 * having below-base forms and following the base consonant. 965 * The exception is vattu, which may appear below half forms 966 * as well as below the base glyph. The feature 'below-base 967 * form' will be applied to all such occurrences of Ra as well." 968 * 969 * Test case: U+0924,U+094D,U+0930,U+094d,U+0915 970 * with Sanskrit 2003 font. 971 * 972 * However, note that Ra,Halant,ZWJ is the correct way to 973 * request eyelash form of Ra, so we wouldbn't inhibit it 974 * in that sequence. 975 * 976 * Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915 977 */ 978 for (unsigned int i = start; i + 1 < base; i++) 979 if (info[i ].indic_category() == OT_Ra && 980 info[i+1].indic_category() == OT_H && 981 (i + 2 == base || 982 info[i+2].indic_category() != OT_ZWJ)) 983 { 984 info[i ].mask |= indic_plan->mask_array[BLWF]; 985 info[i+1].mask |= indic_plan->mask_array[BLWF]; 986 } 987 } 988 989 if (indic_plan->mask_array[PREF] && base + 2 < end) 990 { 991 /* Find a Halant,Ra sequence and mark it for pre-base reordering processing. */ 992 for (unsigned int i = base + 1; i + 1 < end; i++) { 993 hb_codepoint_t glyphs[2] = {info[i].codepoint, info[i + 1].codepoint}; 994 if (indic_plan->pref.would_substitute (glyphs, ARRAY_LENGTH (glyphs), true, face)) 995 { 996 info[i++].mask |= indic_plan->mask_array[PREF]; 997 info[i++].mask |= indic_plan->mask_array[PREF]; 998 999 /* Mark the subsequent stuff with 'cfar'. Used in Khmer. 1000 * Read the feature spec. 1001 * This allows distinguishing the following cases with MS Khmer fonts: 1002 * U+1784,U+17D2,U+179A,U+17D2,U+1782 1003 * U+1784,U+17D2,U+1782,U+17D2,U+179A 1004 */ 1005 for (; i < end; i++) 1006 info[i].mask |= indic_plan->mask_array[CFAR]; 1007 1008 break; 1009 } 1010 } 1011 } 1012 1013 /* Apply ZWJ/ZWNJ effects */ 1014 for (unsigned int i = start + 1; i < end; i++) 1015 if (is_joiner (info[i])) { 1016 bool non_joiner = info[i].indic_category() == OT_ZWNJ; 1017 unsigned int j = i; 1018 1019 do { 1020 j--; 1021 1022 /* ZWJ/ZWNJ should disable CJCT. They do that by simply 1023 * being there, since we don't skip them for the CJCT 1024 * feature (ie. F_MANUAL_ZWJ) */ 1025 1026 /* A ZWNJ disables HALF. */ 1027 if (non_joiner) 1028 info[j].mask &= ~indic_plan->mask_array[HALF]; 1029 1030 } while (j > start && !is_consonant (info[j])); 1031 } 1032 } 1033 1034 1035 static void 1036 initial_reordering_vowel_syllable (const hb_ot_shape_plan_t *plan, 1037 hb_face_t *face, 1038 hb_buffer_t *buffer, 1039 unsigned int start, unsigned int end) 1040 { 1041 /* We made the vowels look like consonants. So let's call the consonant logic! */ 1042 initial_reordering_consonant_syllable (plan, face, buffer, start, end); 1043 } 1044 1045 static void 1046 initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan, 1047 hb_face_t *face, 1048 hb_buffer_t *buffer, 1049 unsigned int start, unsigned int end) 1050 { 1051 /* We treat NBSP/dotted-circle as if they are consonants, so we should just chain. 1052 * Only if not in compatibility mode that is... */ 1053 1054 if (hb_options ().uniscribe_bug_compatible) 1055 { 1056 /* For dotted-circle, this is what Uniscribe does: 1057 * If dotted-circle is the last glyph, it just does nothing. 1058 * Ie. It doesn't form Reph. */ 1059 if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE) 1060 return; 1061 } 1062 1063 initial_reordering_consonant_syllable (plan, face, buffer, start, end); 1064 } 1065 1066 static void 1067 initial_reordering_broken_cluster (const hb_ot_shape_plan_t *plan, 1068 hb_face_t *face, 1069 hb_buffer_t *buffer, 1070 unsigned int start, unsigned int end) 1071 { 1072 /* We already inserted dotted-circles, so just call the standalone_cluster. */ 1073 initial_reordering_standalone_cluster (plan, face, buffer, start, end); 1074 } 1075 1076 static void 1077 initial_reordering_non_indic_cluster (const hb_ot_shape_plan_t *plan HB_UNUSED, 1078 hb_face_t *face HB_UNUSED, 1079 hb_buffer_t *buffer HB_UNUSED, 1080 unsigned int start HB_UNUSED, unsigned int end HB_UNUSED) 1081 { 1082 /* Nothing to do right now. If we ever switch to using the output 1083 * buffer in the reordering process, we'd need to next_glyph() here. */ 1084 } 1085 1086 1087 static void 1088 initial_reordering_syllable (const hb_ot_shape_plan_t *plan, 1089 hb_face_t *face, 1090 hb_buffer_t *buffer, 1091 unsigned int start, unsigned int end) 1092 { 1093 syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F); 1094 switch (syllable_type) { 1095 case consonant_syllable: initial_reordering_consonant_syllable (plan, face, buffer, start, end); return; 1096 case vowel_syllable: initial_reordering_vowel_syllable (plan, face, buffer, start, end); return; 1097 case standalone_cluster: initial_reordering_standalone_cluster (plan, face, buffer, start, end); return; 1098 case broken_cluster: initial_reordering_broken_cluster (plan, face, buffer, start, end); return; 1099 case non_indic_cluster: initial_reordering_non_indic_cluster (plan, face, buffer, start, end); return; 1100 } 1101 } 1102 1103 static inline void 1104 insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED, 1105 hb_font_t *font, 1106 hb_buffer_t *buffer) 1107 { 1108 /* Note: This loop is extra overhead, but should not be measurable. */ 1109 bool has_broken_syllables = false; 1110 unsigned int count = buffer->len; 1111 for (unsigned int i = 0; i < count; i++) 1112 if ((buffer->info[i].syllable() & 0x0F) == broken_cluster) { 1113 has_broken_syllables = true; 1114 break; 1115 } 1116 if (likely (!has_broken_syllables)) 1117 return; 1118 1119 1120 hb_codepoint_t dottedcircle_glyph; 1121 if (!font->get_glyph (0x25CC, 0, &dottedcircle_glyph)) 1122 return; 1123 1124 hb_glyph_info_t dottedcircle = {0}; 1125 dottedcircle.codepoint = 0x25CC; 1126 set_indic_properties (dottedcircle); 1127 dottedcircle.codepoint = dottedcircle_glyph; 1128 1129 buffer->clear_output (); 1130 1131 buffer->idx = 0; 1132 unsigned int last_syllable = 0; 1133 while (buffer->idx < buffer->len) 1134 { 1135 unsigned int syllable = buffer->cur().syllable(); 1136 syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F); 1137 if (unlikely (last_syllable != syllable && syllable_type == broken_cluster)) 1138 { 1139 last_syllable = syllable; 1140 1141 hb_glyph_info_t info = dottedcircle; 1142 info.cluster = buffer->cur().cluster; 1143 info.mask = buffer->cur().mask; 1144 info.syllable() = buffer->cur().syllable(); 1145 1146 /* Insert dottedcircle after possible Repha. */ 1147 while (buffer->idx < buffer->len && 1148 last_syllable == buffer->cur().syllable() && 1149 buffer->cur().indic_category() == OT_Repha) 1150 buffer->next_glyph (); 1151 1152 buffer->output_info (info); 1153 } 1154 else 1155 buffer->next_glyph (); 1156 } 1157 1158 buffer->swap_buffers (); 1159 } 1160 1161 static void 1162 initial_reordering (const hb_ot_shape_plan_t *plan, 1163 hb_font_t *font, 1164 hb_buffer_t *buffer) 1165 { 1166 update_consonant_positions (plan, font, buffer); 1167 insert_dotted_circles (plan, font, buffer); 1168 1169 hb_glyph_info_t *info = buffer->info; 1170 unsigned int count = buffer->len; 1171 if (unlikely (!count)) return; 1172 unsigned int last = 0; 1173 unsigned int last_syllable = info[0].syllable(); 1174 for (unsigned int i = 1; i < count; i++) 1175 if (last_syllable != info[i].syllable()) { 1176 initial_reordering_syllable (plan, font->face, buffer, last, i); 1177 last = i; 1178 last_syllable = info[last].syllable(); 1179 } 1180 initial_reordering_syllable (plan, font->face, buffer, last, count); 1181 } 1182 1183 static void 1184 final_reordering_syllable (const hb_ot_shape_plan_t *plan, 1185 hb_buffer_t *buffer, 1186 unsigned int start, unsigned int end) 1187 { 1188 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; 1189 hb_glyph_info_t *info = buffer->info; 1190 1191 /* 4. Final reordering: 1192 * 1193 * After the localized forms and basic shaping forms GSUB features have been 1194 * applied (see below), the shaping engine performs some final glyph 1195 * reordering before applying all the remaining font features to the entire 1196 * cluster. 1197 */ 1198 1199 /* Find base again */ 1200 unsigned int base; 1201 for (base = start; base < end; base++) 1202 if (info[base].indic_position() >= POS_BASE_C) { 1203 if (start < base && info[base].indic_position() > POS_BASE_C) 1204 base--; 1205 break; 1206 } 1207 if (base == end && start < base && 1208 info[base - 1].indic_category() != OT_ZWJ) 1209 base--; 1210 while (start < base && 1211 (info[base].indic_category() == OT_H || 1212 info[base].indic_category() == OT_N)) 1213 base--; 1214 1215 1216 /* o Reorder matras: 1217 * 1218 * If a pre-base matra character had been reordered before applying basic 1219 * features, the glyph can be moved closer to the main consonant based on 1220 * whether half-forms had been formed. Actual position for the matra is 1221 * defined as after last standalone halant glyph, after initial matra 1222 * position and before the main consonant. If ZWJ or ZWNJ follow this 1223 * halant, position is moved after it. 1224 */ 1225 1226 if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */ 1227 { 1228 /* If we lost track of base, alas, position before last thingy. */ 1229 unsigned int new_pos = base == end ? base - 2 : base - 1; 1230 1231 /* Malayalam / Tamil do not have "half" forms or explicit virama forms. 1232 * The glyphs formed by 'half' are Chillus or ligated explicit viramas. 1233 * We want to position matra after them. 1234 */ 1235 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL) 1236 { 1237 while (new_pos > start && 1238 !(is_one_of (info[new_pos], (FLAG (OT_M) | FLAG (OT_H) | FLAG (OT_Coeng))))) 1239 new_pos--; 1240 1241 /* If we found no Halant we are done. 1242 * Otherwise only proceed if the Halant does 1243 * not belong to the Matra itself! */ 1244 if (is_halant_or_coeng (info[new_pos]) && 1245 info[new_pos].indic_position() != POS_PRE_M) 1246 { 1247 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */ 1248 if (new_pos + 1 < end && is_joiner (info[new_pos + 1])) 1249 new_pos++; 1250 } 1251 else 1252 new_pos = start; /* No move. */ 1253 } 1254 1255 if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M) 1256 { 1257 /* Now go see if there's actually any matras... */ 1258 for (unsigned int i = new_pos; i > start; i--) 1259 if (info[i - 1].indic_position () == POS_PRE_M) 1260 { 1261 unsigned int old_pos = i - 1; 1262 hb_glyph_info_t tmp = info[old_pos]; 1263 memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0])); 1264 info[new_pos] = tmp; 1265 if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */ 1266 base--; 1267 new_pos--; 1268 } 1269 buffer->merge_clusters (new_pos, MIN (end, base + 1)); 1270 } else { 1271 for (unsigned int i = start; i < base; i++) 1272 if (info[i].indic_position () == POS_PRE_M) { 1273 buffer->merge_clusters (i, MIN (end, base + 1)); 1274 break; 1275 } 1276 } 1277 } 1278 1279 1280 /* o Reorder reph: 1281 * 1282 * Rephs original position is always at the beginning of the syllable, 1283 * (i.e. it is not reordered at the character reordering stage). However, 1284 * it will be reordered according to the basic-forms shaping results. 1285 * Possible positions for reph, depending on the script, are; after main, 1286 * before post-base consonant forms, and after post-base consonant forms. 1287 */ 1288 1289 /* If there's anything after the Ra that has the REPH pos, it ought to be halant. 1290 * Which means that the font has failed to ligate the Reph. In which case, we 1291 * shouldn't move. */ 1292 if (start + 1 < end && 1293 info[start].indic_position() == POS_RA_TO_BECOME_REPH && 1294 info[start + 1].indic_position() != POS_RA_TO_BECOME_REPH) 1295 { 1296 unsigned int new_reph_pos; 1297 reph_position_t reph_pos = indic_plan->config->reph_pos; 1298 1299 /* XXX Figure out old behavior too */ 1300 1301 /* 1. If reph should be positioned after post-base consonant forms, 1302 * proceed to step 5. 1303 */ 1304 if (reph_pos == REPH_POS_AFTER_POST) 1305 { 1306 goto reph_step_5; 1307 } 1308 1309 /* 2. If the reph repositioning class is not after post-base: target 1310 * position is after the first explicit halant glyph between the 1311 * first post-reph consonant and last main consonant. If ZWJ or ZWNJ 1312 * are following this halant, position is moved after it. If such 1313 * position is found, this is the target position. Otherwise, 1314 * proceed to the next step. 1315 * 1316 * Note: in old-implementation fonts, where classifications were 1317 * fixed in shaping engine, there was no case where reph position 1318 * will be found on this step. 1319 */ 1320 { 1321 new_reph_pos = start + 1; 1322 while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos])) 1323 new_reph_pos++; 1324 1325 if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos])) 1326 { 1327 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */ 1328 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1])) 1329 new_reph_pos++; 1330 goto reph_move; 1331 } 1332 } 1333 1334 /* 3. If reph should be repositioned after the main consonant: find the 1335 * first consonant not ligated with main, or find the first 1336 * consonant that is not a potential pre-base reordering Ra. 1337 */ 1338 if (reph_pos == REPH_POS_AFTER_MAIN) 1339 { 1340 new_reph_pos = base; 1341 /* XXX Skip potential pre-base reordering Ra. */ 1342 while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN) 1343 new_reph_pos++; 1344 if (new_reph_pos < end) 1345 goto reph_move; 1346 } 1347 1348 /* 4. If reph should be positioned before post-base consonant, find 1349 * first post-base classified consonant not ligated with main. If no 1350 * consonant is found, the target position should be before the 1351 * first matra, syllable modifier sign or vedic sign. 1352 */ 1353 /* This is our take on what step 4 is trying to say (and failing, BADLY). */ 1354 if (reph_pos == REPH_POS_AFTER_SUB) 1355 { 1356 new_reph_pos = base; 1357 while (new_reph_pos < end && 1358 !( FLAG (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD)))) 1359 new_reph_pos++; 1360 if (new_reph_pos < end) 1361 goto reph_move; 1362 } 1363 1364 /* 5. If no consonant is found in steps 3 or 4, move reph to a position 1365 * immediately before the first post-base matra, syllable modifier 1366 * sign or vedic sign that has a reordering class after the intended 1367 * reph position. For example, if the reordering position for reph 1368 * is post-main, it will skip above-base matras that also have a 1369 * post-main position. 1370 */ 1371 reph_step_5: 1372 { 1373 /* Copied from step 2. */ 1374 new_reph_pos = start + 1; 1375 while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos])) 1376 new_reph_pos++; 1377 1378 if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos])) 1379 { 1380 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */ 1381 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1])) 1382 new_reph_pos++; 1383 goto reph_move; 1384 } 1385 } 1386 1387 /* 6. Otherwise, reorder reph to the end of the syllable. 1388 */ 1389 { 1390 new_reph_pos = end - 1; 1391 while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD) 1392 new_reph_pos--; 1393 1394 /* 1395 * If the Reph is to be ending up after a Matra,Halant sequence, 1396 * position it before that Halant so it can interact with the Matra. 1397 * However, if it's a plain Consonant,Halant we shouldn't do that. 1398 * Uniscribe doesn't do this. 1399 * TEST: U+0930,U+094D,U+0915,U+094B,U+094D 1400 */ 1401 if (!hb_options ().uniscribe_bug_compatible && 1402 unlikely (is_halant_or_coeng (info[new_reph_pos]))) { 1403 for (unsigned int i = base + 1; i < new_reph_pos; i++) 1404 if (info[i].indic_category() == OT_M) { 1405 /* Ok, got it. */ 1406 new_reph_pos--; 1407 } 1408 } 1409 goto reph_move; 1410 } 1411 1412 reph_move: 1413 { 1414 /* Yay, one big cluster! Merge before moving. */ 1415 buffer->merge_clusters (start, end); 1416 1417 /* Move */ 1418 hb_glyph_info_t reph = info[start]; 1419 memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0])); 1420 info[new_reph_pos] = reph; 1421 if (start < base && base <= new_reph_pos) 1422 base--; 1423 } 1424 } 1425 1426 1427 /* o Reorder pre-base reordering consonants: 1428 * 1429 * If a pre-base reordering consonant is found, reorder it according to 1430 * the following rules: 1431 */ 1432 1433 if (indic_plan->mask_array[PREF] && base + 1 < end) /* Otherwise there can't be any pre-base reordering Ra. */ 1434 { 1435 for (unsigned int i = base + 1; i < end; i++) 1436 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0) 1437 { 1438 /* 1. Only reorder a glyph produced by substitution during application 1439 * of the <pref> feature. (Note that a font may shape a Ra consonant with 1440 * the feature generally but block it in certain contexts.) 1441 */ 1442 if (i + 1 == end || (info[i + 1].mask & indic_plan->mask_array[PREF]) == 0) 1443 { 1444 /* 1445 * 2. Try to find a target position the same way as for pre-base matra. 1446 * If it is found, reorder pre-base consonant glyph. 1447 * 1448 * 3. If position is not found, reorder immediately before main 1449 * consonant. 1450 */ 1451 1452 unsigned int new_pos = base; 1453 /* Malayalam / Tamil do not have "half" forms or explicit virama forms. 1454 * The glyphs formed by 'half' are Chillus or ligated explicit viramas. 1455 * We want to position matra after them. 1456 */ 1457 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL) 1458 { 1459 while (new_pos > start && 1460 !(is_one_of (info[new_pos - 1], FLAG(OT_M) | HALANT_OR_COENG_FLAGS))) 1461 new_pos--; 1462 1463 /* In Khmer coeng model, a V,Ra can go *after* matras. If it goes after a 1464 * split matra, it should be reordered to *before* the left part of such matra. */ 1465 if (new_pos > start && info[new_pos - 1].indic_category() == OT_M) 1466 { 1467 unsigned int old_pos = i; 1468 for (unsigned int i = base + 1; i < old_pos; i++) 1469 if (info[i].indic_category() == OT_M) 1470 { 1471 new_pos--; 1472 break; 1473 } 1474 } 1475 } 1476 1477 if (new_pos > start && is_halant_or_coeng (info[new_pos - 1])) 1478 { 1479 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */ 1480 if (new_pos < end && is_joiner (info[new_pos])) 1481 new_pos++; 1482 } 1483 1484 { 1485 unsigned int old_pos = i; 1486 buffer->merge_clusters (new_pos, old_pos + 1); 1487 hb_glyph_info_t tmp = info[old_pos]; 1488 memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0])); 1489 info[new_pos] = tmp; 1490 if (new_pos <= base && base < old_pos) 1491 base++; 1492 } 1493 } 1494 1495 break; 1496 } 1497 } 1498 1499 1500 /* Apply 'init' to the Left Matra if it's a word start. */ 1501 if (info[start].indic_position () == POS_PRE_M && 1502 (!start || 1503 !(FLAG (_hb_glyph_info_get_general_category (&info[start - 1])) & 1504 FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))) 1505 info[start].mask |= indic_plan->mask_array[INIT]; 1506 1507 1508 /* 1509 * Finish off the clusters and go home! 1510 */ 1511 if (hb_options ().uniscribe_bug_compatible) 1512 { 1513 /* Uniscribe merges the entire cluster. 1514 * This means, half forms are submerged into the main consonants cluster. 1515 * This is unnecessary, and makes cursor positioning harder, but that's what 1516 * Uniscribe does. */ 1517 buffer->merge_clusters (start, end); 1518 } 1519 } 1520 1521 1522 static void 1523 final_reordering (const hb_ot_shape_plan_t *plan, 1524 hb_font_t *font HB_UNUSED, 1525 hb_buffer_t *buffer) 1526 { 1527 unsigned int count = buffer->len; 1528 if (unlikely (!count)) return; 1529 1530 hb_glyph_info_t *info = buffer->info; 1531 unsigned int last = 0; 1532 unsigned int last_syllable = info[0].syllable(); 1533 for (unsigned int i = 1; i < count; i++) 1534 if (last_syllable != info[i].syllable()) { 1535 final_reordering_syllable (plan, buffer, last, i); 1536 last = i; 1537 last_syllable = info[last].syllable(); 1538 } 1539 final_reordering_syllable (plan, buffer, last, count); 1540 1541 /* Zero syllables now... */ 1542 for (unsigned int i = 0; i < count; i++) 1543 info[i].syllable() = 0; 1544 1545 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category); 1546 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position); 1547 } 1548 1549 1550 static hb_ot_shape_normalization_mode_t 1551 normalization_preference_indic (const hb_segment_properties_t *props HB_UNUSED) 1552 { 1553 return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT; 1554 } 1555 1556 static bool 1557 decompose_indic (const hb_ot_shape_normalize_context_t *c, 1558 hb_codepoint_t ab, 1559 hb_codepoint_t *a, 1560 hb_codepoint_t *b) 1561 { 1562 switch (ab) 1563 { 1564 /* Don't decompose these. */ 1565 case 0x0931 : return false; 1566 case 0x0B94 : return false; 1567 1568 1569 /* 1570 * Decompose split matras that don't have Unicode decompositions. 1571 */ 1572 1573 case 0x0F77 : *a = 0x0FB2; *b= 0x0F81; return true; 1574 case 0x0F79 : *a = 0x0FB3; *b= 0x0F81; return true; 1575 case 0x17BE : *a = 0x17C1; *b= 0x17BE; return true; 1576 case 0x17BF : *a = 0x17C1; *b= 0x17BF; return true; 1577 case 0x17C0 : *a = 0x17C1; *b= 0x17C0; return true; 1578 case 0x17C4 : *a = 0x17C1; *b= 0x17C4; return true; 1579 case 0x17C5 : *a = 0x17C1; *b= 0x17C5; return true; 1580 case 0x1925 : *a = 0x1920; *b= 0x1923; return true; 1581 case 0x1926 : *a = 0x1920; *b= 0x1924; return true; 1582 case 0x1B3C : *a = 0x1B42; *b= 0x1B3C; return true; 1583 case 0x1112E : *a = 0x11127; *b= 0x11131; return true; 1584 case 0x1112F : *a = 0x11127; *b= 0x11132; return true; 1585 #if 0 1586 /* This one has no decomposition in Unicode, but needs no decomposition either. */ 1587 /* case 0x0AC9 : return false; */ 1588 case 0x0B57 : *a = no decomp, -> RIGHT; return true; 1589 case 0x1C29 : *a = no decomp, -> LEFT; return true; 1590 case 0xA9C0 : *a = no decomp, -> RIGHT; return true; 1591 case 0x111BF : *a = no decomp, -> ABOVE; return true; 1592 #endif 1593 } 1594 1595 if ((ab == 0x0DDA || hb_in_range<hb_codepoint_t> (ab, 0x0DDC, 0x0DDE))) 1596 { 1597 /* 1598 * Sinhala split matras... Let the fun begin. 1599 * 1600 * These four characters have Unicode decompositions. However, Uniscribe 1601 * decomposes them "Khmer-style", that is, it uses the character itself to 1602 * get the second half. The first half of all four decompositions is always 1603 * U+0DD9. 1604 * 1605 * Now, there are buggy fonts, namely, the widely used lklug.ttf, that are 1606 * broken with Uniscribe. But we need to support them. As such, we only 1607 * do the Uniscribe-style decomposition if the character is transformed into 1608 * its "sec.half" form by the 'pstf' feature. Otherwise, we fall back to 1609 * Unicode decomposition. 1610 * 1611 * Note that we can't unconditionally use Unicode decomposition. That would 1612 * break some other fonts, that are designed to work with Uniscribe, and 1613 * don't have positioning features for the Unicode-style decomposition. 1614 * 1615 * Argh... 1616 * 1617 * The Uniscribe behavior is now documented in the newly published Sinhala 1618 * spec in 2012: 1619 * 1620 * http://www.microsoft.com/typography/OpenTypeDev/sinhala/intro.htm#shaping 1621 */ 1622 1623 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data; 1624 1625 hb_codepoint_t glyph; 1626 1627 if (hb_options ().uniscribe_bug_compatible || 1628 (c->font->get_glyph (ab, 0, &glyph) && 1629 indic_plan->pstf.would_substitute (&glyph, 1, true, c->font->face))) 1630 { 1631 /* Ok, safe to use Uniscribe-style decomposition. */ 1632 *a = 0x0DD9; 1633 *b = ab; 1634 return true; 1635 } 1636 } 1637 1638 return c->unicode->decompose (ab, a, b); 1639 } 1640 1641 static bool 1642 compose_indic (const hb_ot_shape_normalize_context_t *c, 1643 hb_codepoint_t a, 1644 hb_codepoint_t b, 1645 hb_codepoint_t *ab) 1646 { 1647 /* Avoid recomposing split matras. */ 1648 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a))) 1649 return false; 1650 1651 /* Composition-exclusion exceptions that we want to recompose. */ 1652 if (a == 0x09AF && b == 0x09BC) { *ab = 0x09DF; return true; } 1653 1654 return c->unicode->compose (a, b, ab); 1655 } 1656 1657 1658 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic = 1659 { 1660 "indic", 1661 collect_features_indic, 1662 override_features_indic, 1663 data_create_indic, 1664 data_destroy_indic, 1665 NULL, /* preprocess_text */ 1666 normalization_preference_indic, 1667 decompose_indic, 1668 compose_indic, 1669 setup_masks_indic, 1670 HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE, 1671 false, /* fallback_position */ 1672 }; 1673
