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) & ~0x7Fu) == (Base)) 41 42 #define IS_DEVA(u) (IN_HALF_BLOCK (u, 0x0900u)) 43 #define IS_BENG(u) (IN_HALF_BLOCK (u, 0x0980u)) 44 #define IS_GURU(u) (IN_HALF_BLOCK (u, 0x0A00u)) 45 #define IS_GUJR(u) (IN_HALF_BLOCK (u, 0x0A80u)) 46 #define IS_ORYA(u) (IN_HALF_BLOCK (u, 0x0B00u)) 47 #define IS_TAML(u) (IN_HALF_BLOCK (u, 0x0B80u)) 48 #define IS_TELU(u) (IN_HALF_BLOCK (u, 0x0C00u)) 49 #define IS_KNDA(u) (IN_HALF_BLOCK (u, 0x0C80u)) 50 #define IS_MLYM(u) (IN_HALF_BLOCK (u, 0x0D00u)) 51 #define IS_SINH(u) (IN_HALF_BLOCK (u, 0x0D80u)) 52 #define IS_KHMR(u) (IN_HALF_BLOCK (u, 0x1780u)) 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 <= 0x0C42u ? POS_BEFORE_SUB : POS_AFTER_SUB) : \ 64 IS_KNDA(u) ? (u < 0x0CC3u || u > 0xCD6u ? 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 0x0930u, /* Devanagari */ 116 0x09B0u, /* Bengali */ 117 0x09F0u, /* Bengali */ 118 0x0A30u, /* Gurmukhi */ /* No Reph */ 119 0x0AB0u, /* Gujarati */ 120 0x0B30u, /* Oriya */ 121 0x0BB0u, /* Tamil */ /* No Reph */ 122 0x0C30u, /* Telugu */ /* Reph formed only with ZWJ */ 123 0x0CB0u, /* Kannada */ 124 0x0D30u, /* Malayalam */ /* No Reph, Logical Repha */ 125 126 0x0DBBu, /* Sinhala */ /* Reph formed only with ZWJ */ 127 128 0x179Au, /* Khmer */ /* No Reph, Visual Repha */ 129 }; 130 131 static inline bool 132 is_ra (hb_codepoint_t u) 133 { 134 for (unsigned int i = 0; i < ARRAY_LENGTH (ra_chars); i++) 135 if (u == ra_chars[i]) 136 return true; 137 return false; 138 } 139 140 static inline bool 141 is_one_of (const hb_glyph_info_t &info, unsigned int flags) 142 { 143 /* If it ligated, all bets are off. */ 144 if (_hb_glyph_info_ligated (&info)) return false; 145 return !!(FLAG_UNSAFE (info.indic_category()) & flags); 146 } 147 148 static inline bool 149 is_joiner (const hb_glyph_info_t &info) 150 { 151 return is_one_of (info, JOINER_FLAGS); 152 } 153 154 static inline bool 155 is_consonant (const hb_glyph_info_t &info) 156 { 157 return is_one_of (info, CONSONANT_FLAGS); 158 } 159 160 static inline bool 161 is_halant_or_coeng (const hb_glyph_info_t &info) 162 { 163 return is_one_of (info, HALANT_OR_COENG_FLAGS); 164 } 165 166 static inline void 167 set_indic_properties (hb_glyph_info_t &info) 168 { 169 hb_codepoint_t u = info.codepoint; 170 unsigned int type = hb_indic_get_categories (u); 171 indic_category_t cat = (indic_category_t) (type & 0x7Fu); 172 indic_position_t pos = (indic_position_t) (type >> 8); 173 174 175 /* 176 * Re-assign category 177 */ 178 179 /* The following act more like the Bindus. */ 180 if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x0953u, 0x0954u))) 181 cat = OT_SM; 182 /* The following act like consonants. */ 183 else if (unlikely (hb_in_ranges<hb_codepoint_t> (u, 0x0A72u, 0x0A73u, 184 0x1CF5u, 0x1CF6u))) 185 cat = OT_C; 186 /* TODO: The following should only be allowed after a Visarga. 187 * For now, just treat them like regular tone marks. */ 188 else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1CE2u, 0x1CE8u))) 189 cat = OT_A; 190 /* TODO: The following should only be allowed after some of 191 * the nasalization marks, maybe only for U+1CE9..U+1CF1. 192 * For now, just treat them like tone marks. */ 193 else if (unlikely (u == 0x1CEDu)) 194 cat = OT_A; 195 /* The following take marks in standalone clusters, similar to Avagraha. */ 196 else if (unlikely (hb_in_ranges<hb_codepoint_t> (u, 0xA8F2u, 0xA8F7u, 197 0x1CE9u, 0x1CECu, 198 0x1CEEu, 0x1CF1u))) 199 { 200 cat = OT_Symbol; 201 static_assert (((int) INDIC_SYLLABIC_CATEGORY_AVAGRAHA == OT_Symbol), ""); 202 } 203 else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x17CDu, 0x17D1u) || 204 u == 0x17CBu || u == 0x17D3u || u == 0x17DDu)) /* Khmer Various signs */ 205 { 206 /* These can occur mid-syllable (eg. before matras), even though Unicode marks them as Syllable_Modifier. 207 * https://github.com/roozbehp/unicode-data/issues/5 */ 208 cat = OT_M; 209 pos = POS_ABOVE_C; 210 } 211 else if (unlikely (u == 0x0A51u)) 212 { 213 /* https://github.com/harfbuzz/harfbuzz/issues/524 */ 214 cat = OT_M; 215 pos = POS_BELOW_C; 216 } 217 218 /* According to ScriptExtensions.txt, these Grantha marks may also be used in Tamil, 219 * so the Indic shaper needs to know their categories. */ 220 else if (unlikely (u == 0x11301u || u == 0x11303u)) cat = OT_SM; 221 else if (unlikely (u == 0x1133cu)) cat = OT_N; 222 223 else if (unlikely (u == 0x0AFBu)) cat = OT_N; /* https://github.com/harfbuzz/harfbuzz/issues/552 */ 224 225 else if (unlikely (u == 0x0980u)) cat = OT_PLACEHOLDER; /* https://github.com/harfbuzz/harfbuzz/issues/538 */ 226 else if (unlikely (u == 0x0C80u)) cat = OT_PLACEHOLDER; /* https://github.com/harfbuzz/harfbuzz/pull/623 */ 227 else if (unlikely (u == 0x17C6u)) cat = OT_N; /* Khmer Bindu doesn't like to be repositioned. */ 228 else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x2010u, 0x2011u))) 229 cat = OT_PLACEHOLDER; 230 else if (unlikely (u == 0x25CCu)) cat = OT_DOTTEDCIRCLE; 231 232 233 /* 234 * Re-assign position. 235 */ 236 237 if ((FLAG_UNSAFE (cat) & CONSONANT_FLAGS)) 238 { 239 pos = POS_BASE_C; 240 if (is_ra (u)) 241 cat = OT_Ra; 242 } 243 else if (cat == OT_M) 244 { 245 pos = matra_position (u, pos); 246 } 247 else if ((FLAG_UNSAFE (cat) & (FLAG (OT_SM) | FLAG (OT_VD) | FLAG (OT_A) | FLAG (OT_Symbol)))) 248 { 249 pos = POS_SMVD; 250 } 251 252 if (unlikely (u == 0x0B01u)) pos = POS_BEFORE_SUB; /* Oriya Bindu is BeforeSub in the spec. */ 253 254 255 256 info.indic_category() = cat; 257 info.indic_position() = pos; 258 } 259 260 /* 261 * Things above this line should ideally be moved to the Indic table itself. 262 */ 263 264 265 /* 266 * Indic configurations. Note that we do not want to keep every single script-specific 267 * behavior in these tables necessarily. This should mainly be used for per-script 268 * properties that are cheaper keeping here, than in the code. Ie. if, say, one and 269 * only one script has an exception, that one script can be if'ed directly in the code, 270 * instead of adding a new flag in these structs. 271 */ 272 273 enum base_position_t { 274 BASE_POS_FIRST, 275 BASE_POS_LAST_SINHALA, 276 BASE_POS_LAST 277 }; 278 enum reph_position_t { 279 REPH_POS_AFTER_MAIN = POS_AFTER_MAIN, 280 REPH_POS_BEFORE_SUB = POS_BEFORE_SUB, 281 REPH_POS_AFTER_SUB = POS_AFTER_SUB, 282 REPH_POS_BEFORE_POST = POS_BEFORE_POST, 283 REPH_POS_AFTER_POST = POS_AFTER_POST, 284 REPH_POS_DONT_CARE = POS_RA_TO_BECOME_REPH 285 }; 286 enum reph_mode_t { 287 REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */ 288 REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */ 289 REPH_MODE_VIS_REPHA, /* Encoded Repha character, no reordering needed. */ 290 REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */ 291 }; 292 enum blwf_mode_t { 293 BLWF_MODE_PRE_AND_POST, /* Below-forms feature applied to pre-base and post-base. */ 294 BLWF_MODE_POST_ONLY /* Below-forms feature applied to post-base only. */ 295 }; 296 struct indic_config_t 297 { 298 hb_script_t script; 299 bool has_old_spec; 300 hb_codepoint_t virama; 301 base_position_t base_pos; 302 reph_position_t reph_pos; 303 reph_mode_t reph_mode; 304 blwf_mode_t blwf_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_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, 311 {HB_SCRIPT_DEVANAGARI,true, 0x094Du,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, 312 {HB_SCRIPT_BENGALI, true, 0x09CDu,BASE_POS_LAST, REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, 313 {HB_SCRIPT_GURMUKHI, true, 0x0A4Du,BASE_POS_LAST, REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, 314 {HB_SCRIPT_GUJARATI, true, 0x0ACDu,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, 315 {HB_SCRIPT_ORIYA, true, 0x0B4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, 316 {HB_SCRIPT_TAMIL, true, 0x0BCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, 317 {HB_SCRIPT_TELUGU, true, 0x0C4Du,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_POST_ONLY}, 318 {HB_SCRIPT_KANNADA, true, 0x0CCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_POST_ONLY}, 319 {HB_SCRIPT_MALAYALAM, true, 0x0D4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA,BLWF_MODE_PRE_AND_POST}, 320 {HB_SCRIPT_SINHALA, false,0x0DCAu,BASE_POS_LAST_SINHALA, 321 REPH_POS_AFTER_MAIN, REPH_MODE_EXPLICIT, BLWF_MODE_PRE_AND_POST}, 322 {HB_SCRIPT_KHMER, false,0x17D2u,BASE_POS_FIRST,REPH_POS_DONT_CARE, REPH_MODE_VIS_REPHA,BLWF_MODE_PRE_AND_POST}, 323 }; 324 325 326 327 /* 328 * Indic shaper. 329 */ 330 331 struct feature_list_t { 332 hb_tag_t tag; 333 hb_ot_map_feature_flags_t flags; 334 }; 335 336 static const feature_list_t 337 indic_features[] = 338 { 339 /* 340 * Basic features. 341 * These features are applied in order, one at a time, after initial_reordering. 342 */ 343 {HB_TAG('n','u','k','t'), F_GLOBAL}, 344 {HB_TAG('a','k','h','n'), F_GLOBAL}, 345 {HB_TAG('r','p','h','f'), F_NONE}, 346 {HB_TAG('r','k','r','f'), F_GLOBAL}, 347 {HB_TAG('p','r','e','f'), F_NONE}, 348 {HB_TAG('b','l','w','f'), F_NONE}, 349 {HB_TAG('a','b','v','f'), F_NONE}, 350 {HB_TAG('h','a','l','f'), F_NONE}, 351 {HB_TAG('p','s','t','f'), F_NONE}, 352 {HB_TAG('v','a','t','u'), F_GLOBAL}, 353 {HB_TAG('c','j','c','t'), F_GLOBAL}, 354 {HB_TAG('c','f','a','r'), F_NONE}, 355 /* 356 * Other features. 357 * These features are applied all at once, after final_reordering. 358 * Default Bengali font in Windows for example has intermixed 359 * lookups for init,pres,abvs,blws features. 360 */ 361 {HB_TAG('i','n','i','t'), F_NONE}, 362 {HB_TAG('p','r','e','s'), F_GLOBAL}, 363 {HB_TAG('a','b','v','s'), F_GLOBAL}, 364 {HB_TAG('b','l','w','s'), F_GLOBAL}, 365 {HB_TAG('p','s','t','s'), F_GLOBAL}, 366 {HB_TAG('h','a','l','n'), F_GLOBAL}, 367 /* Positioning features, though we don't care about the types. */ 368 {HB_TAG('d','i','s','t'), F_GLOBAL}, 369 {HB_TAG('a','b','v','m'), F_GLOBAL}, 370 {HB_TAG('b','l','w','m'), F_GLOBAL}, 371 }; 372 373 /* 374 * Must be in the same order as the indic_features array. 375 */ 376 enum { 377 _NUKT, 378 _AKHN, 379 RPHF, 380 _RKRF, 381 PREF, 382 BLWF, 383 ABVF, 384 HALF, 385 PSTF, 386 _VATU, 387 _CJCT, 388 CFAR, 389 390 INIT, 391 _PRES, 392 _ABVS, 393 _BLWS, 394 _PSTS, 395 _HALN, 396 _DIST, 397 _ABVM, 398 _BLWM, 399 400 INDIC_NUM_FEATURES, 401 INDIC_BASIC_FEATURES = INIT /* Don't forget to update this! */ 402 }; 403 404 static void 405 setup_syllables (const hb_ot_shape_plan_t *plan, 406 hb_font_t *font, 407 hb_buffer_t *buffer); 408 static void 409 initial_reordering (const hb_ot_shape_plan_t *plan, 410 hb_font_t *font, 411 hb_buffer_t *buffer); 412 static void 413 final_reordering (const hb_ot_shape_plan_t *plan, 414 hb_font_t *font, 415 hb_buffer_t *buffer); 416 static void 417 clear_syllables (const hb_ot_shape_plan_t *plan, 418 hb_font_t *font, 419 hb_buffer_t *buffer); 420 421 static void 422 collect_features_indic (hb_ot_shape_planner_t *plan) 423 { 424 hb_ot_map_builder_t *map = &plan->map; 425 426 /* Do this before any lookups have been applied. */ 427 map->add_gsub_pause (setup_syllables); 428 429 map->add_global_bool_feature (HB_TAG('l','o','c','l')); 430 /* The Indic specs do not require ccmp, but we apply it here since if 431 * there is a use of it, it's typically at the beginning. */ 432 map->add_global_bool_feature (HB_TAG('c','c','m','p')); 433 434 435 unsigned int i = 0; 436 map->add_gsub_pause (initial_reordering); 437 for (; i < INDIC_BASIC_FEATURES; i++) { 438 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ); 439 map->add_gsub_pause (nullptr); 440 } 441 map->add_gsub_pause (final_reordering); 442 for (; i < INDIC_NUM_FEATURES; i++) { 443 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ); 444 } 445 446 map->add_global_bool_feature (HB_TAG('c','a','l','t')); 447 map->add_global_bool_feature (HB_TAG('c','l','i','g')); 448 449 map->add_gsub_pause (clear_syllables); 450 } 451 452 static void 453 override_features_indic (hb_ot_shape_planner_t *plan) 454 { 455 /* Uniscribe does not apply 'kern' in Khmer. */ 456 if (hb_options ().uniscribe_bug_compatible) 457 { 458 switch ((hb_tag_t) plan->props.script) 459 { 460 case HB_SCRIPT_KHMER: 461 plan->map.add_feature (HB_TAG('k','e','r','n'), 0, F_GLOBAL); 462 break; 463 } 464 } 465 466 plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL); 467 } 468 469 470 struct would_substitute_feature_t 471 { 472 inline void init (const hb_ot_map_t *map, hb_tag_t feature_tag, bool zero_context_) 473 { 474 zero_context = zero_context_; 475 map->get_stage_lookups (0/*GSUB*/, 476 map->get_feature_stage (0/*GSUB*/, feature_tag), 477 &lookups, &count); 478 } 479 480 inline bool would_substitute (const hb_codepoint_t *glyphs, 481 unsigned int glyphs_count, 482 hb_face_t *face) const 483 { 484 for (unsigned int i = 0; i < count; i++) 485 if (hb_ot_layout_lookup_would_substitute_fast (face, lookups[i].index, glyphs, glyphs_count, zero_context)) 486 return true; 487 return false; 488 } 489 490 private: 491 const hb_ot_map_t::lookup_map_t *lookups; 492 unsigned int count; 493 bool zero_context; 494 }; 495 496 struct indic_shape_plan_t 497 { 498 ASSERT_POD (); 499 500 inline bool get_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const 501 { 502 hb_codepoint_t glyph = virama_glyph; 503 if (unlikely (virama_glyph == (hb_codepoint_t) -1)) 504 { 505 if (!config->virama || !font->get_nominal_glyph (config->virama, &glyph)) 506 glyph = 0; 507 /* Technically speaking, the spec says we should apply 'locl' to virama too. 508 * Maybe one day... */ 509 510 /* Our get_nominal_glyph() function needs a font, so we can't get the virama glyph 511 * during shape planning... Instead, overwrite it here. It's safe. Don't worry! */ 512 virama_glyph = glyph; 513 } 514 515 *pglyph = glyph; 516 return glyph != 0; 517 } 518 519 const indic_config_t *config; 520 521 bool is_old_spec; 522 mutable hb_codepoint_t virama_glyph; 523 524 would_substitute_feature_t rphf; 525 would_substitute_feature_t pref; 526 would_substitute_feature_t blwf; 527 would_substitute_feature_t pstf; 528 529 hb_mask_t mask_array[INDIC_NUM_FEATURES]; 530 }; 531 532 static void * 533 data_create_indic (const hb_ot_shape_plan_t *plan) 534 { 535 indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (1, sizeof (indic_shape_plan_t)); 536 if (unlikely (!indic_plan)) 537 return nullptr; 538 539 indic_plan->config = &indic_configs[0]; 540 for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++) 541 if (plan->props.script == indic_configs[i].script) { 542 indic_plan->config = &indic_configs[i]; 543 break; 544 } 545 546 indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FFu) != '2'); 547 indic_plan->virama_glyph = (hb_codepoint_t) -1; 548 549 /* Use zero-context would_substitute() matching for new-spec of the main 550 * Indic scripts, and scripts with one spec only, but not for old-specs. 551 * The new-spec for all dual-spec scripts says zero-context matching happens. 552 * 553 * However, testing with Malayalam shows that old and new spec both allow 554 * context. Testing with Bengali new-spec however shows that it doesn't. 555 * So, the heuristic here is the way it is. It should *only* be changed, 556 * as we discover more cases of what Windows does. DON'T TOUCH OTHERWISE. 557 */ 558 bool zero_context = !indic_plan->is_old_spec && plan->props.script != HB_SCRIPT_MALAYALAM; 559 indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'), zero_context); 560 indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), zero_context); 561 indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'), zero_context); 562 indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'), zero_context); 563 564 for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++) 565 indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ? 566 0 : plan->map.get_1_mask (indic_features[i].tag); 567 568 return indic_plan; 569 } 570 571 static void 572 data_destroy_indic (void *data) 573 { 574 free (data); 575 } 576 577 static indic_position_t 578 consonant_position_from_face (const indic_shape_plan_t *indic_plan, 579 const hb_codepoint_t consonant, 580 const hb_codepoint_t virama, 581 hb_face_t *face) 582 { 583 /* For old-spec, the order of glyphs is Consonant,Virama, 584 * whereas for new-spec, it's Virama,Consonant. However, 585 * some broken fonts (like Free Sans) simply copied lookups 586 * from old-spec to new-spec without modification. 587 * And oddly enough, Uniscribe seems to respect those lookups. 588 * Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds 589 * base at 0. The font however, only has lookups matching 590 * 930,94D in 'blwf', not the expected 94D,930 (with new-spec 591 * table). As such, we simply match both sequences. Seems 592 * to work. */ 593 hb_codepoint_t glyphs[3] = {virama, consonant, virama}; 594 if (indic_plan->blwf.would_substitute (glyphs , 2, face) || 595 indic_plan->blwf.would_substitute (glyphs+1, 2, face)) 596 return POS_BELOW_C; 597 if (indic_plan->pstf.would_substitute (glyphs , 2, face) || 598 indic_plan->pstf.would_substitute (glyphs+1, 2, face)) 599 return POS_POST_C; 600 if (indic_plan->pref.would_substitute (glyphs , 2, face) || 601 indic_plan->pref.would_substitute (glyphs+1, 2, face)) 602 return POS_POST_C; 603 return POS_BASE_C; 604 } 605 606 607 enum syllable_type_t { 608 consonant_syllable, 609 vowel_syllable, 610 standalone_cluster, 611 symbol_cluster, 612 broken_cluster, 613 non_indic_cluster, 614 }; 615 616 #include "hb-ot-shape-complex-indic-machine.hh" 617 618 619 static void 620 setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED, 621 hb_buffer_t *buffer, 622 hb_font_t *font HB_UNUSED) 623 { 624 HB_BUFFER_ALLOCATE_VAR (buffer, indic_category); 625 HB_BUFFER_ALLOCATE_VAR (buffer, indic_position); 626 627 /* We cannot setup masks here. We save information about characters 628 * and setup masks later on in a pause-callback. */ 629 630 unsigned int count = buffer->len; 631 hb_glyph_info_t *info = buffer->info; 632 for (unsigned int i = 0; i < count; i++) 633 set_indic_properties (info[i]); 634 } 635 636 static void 637 setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED, 638 hb_font_t *font HB_UNUSED, 639 hb_buffer_t *buffer) 640 { 641 find_syllables (buffer); 642 foreach_syllable (buffer, start, end) 643 buffer->unsafe_to_break (start, end); 644 } 645 646 static int 647 compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb) 648 { 649 int a = pa->indic_position(); 650 int b = pb->indic_position(); 651 652 return a < b ? -1 : a == b ? 0 : +1; 653 } 654 655 656 657 static void 658 update_consonant_positions (const hb_ot_shape_plan_t *plan, 659 hb_font_t *font, 660 hb_buffer_t *buffer) 661 { 662 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; 663 664 if (indic_plan->config->base_pos != BASE_POS_LAST) 665 return; 666 667 hb_codepoint_t virama; 668 if (indic_plan->get_virama_glyph (font, &virama)) 669 { 670 hb_face_t *face = font->face; 671 unsigned int count = buffer->len; 672 hb_glyph_info_t *info = buffer->info; 673 for (unsigned int i = 0; i < count; i++) 674 if (info[i].indic_position() == POS_BASE_C) 675 { 676 hb_codepoint_t consonant = info[i].codepoint; 677 info[i].indic_position() = consonant_position_from_face (indic_plan, consonant, virama, face); 678 } 679 } 680 } 681 682 683 /* Rules from: 684 * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */ 685 686 static void 687 initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan, 688 hb_face_t *face, 689 hb_buffer_t *buffer, 690 unsigned int start, unsigned int end) 691 { 692 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; 693 hb_glyph_info_t *info = buffer->info; 694 695 /* https://github.com/harfbuzz/harfbuzz/issues/435#issuecomment-335560167 696 * // For compatibility with legacy usage in Kannada, 697 * // Ra+h+ZWJ must behave like Ra+ZWJ+h... 698 */ 699 if (buffer->props.script == HB_SCRIPT_KANNADA && 700 start + 3 <= end && 701 is_one_of (info[start ], FLAG (OT_Ra)) && 702 is_one_of (info[start+1], FLAG (OT_H)) && 703 is_one_of (info[start+2], FLAG (OT_ZWJ))) 704 { 705 buffer->merge_clusters (start+1, start+3); 706 hb_glyph_info_t tmp = info[start+1]; 707 info[start+1] = info[start+2]; 708 info[start+2] = tmp; 709 } 710 711 /* 1. Find base consonant: 712 * 713 * The shaping engine finds the base consonant of the syllable, using the 714 * following algorithm: starting from the end of the syllable, move backwards 715 * until a consonant is found that does not have a below-base or post-base 716 * form (post-base forms have to follow below-base forms), or that is not a 717 * pre-base-reordering Ra, or arrive at the first consonant. The consonant 718 * stopped at will be the base. 719 * 720 * o If the syllable starts with Ra + Halant (in a script that has Reph) 721 * and has more than one consonant, Ra is excluded from candidates for 722 * base consonants. 723 */ 724 725 unsigned int base = end; 726 bool has_reph = false; 727 728 { 729 /* -> If the syllable starts with Ra + Halant (in a script that has Reph) 730 * and has more than one consonant, Ra is excluded from candidates for 731 * base consonants. */ 732 unsigned int limit = start; 733 if (indic_plan->config->reph_pos != REPH_POS_DONT_CARE && 734 indic_plan->mask_array[RPHF] && 735 start + 3 <= end && 736 ( 737 (indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info[start + 2])) || 738 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == OT_ZWJ) 739 )) 740 { 741 /* See if it matches the 'rphf' feature. */ 742 hb_codepoint_t glyphs[3] = {info[start].codepoint, 743 info[start + 1].codepoint, 744 indic_plan->config->reph_mode == REPH_MODE_EXPLICIT ? 745 info[start + 2].codepoint : 0}; 746 if (indic_plan->rphf.would_substitute (glyphs, 2, face) || 747 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && 748 indic_plan->rphf.would_substitute (glyphs, 3, face))) 749 { 750 limit += 2; 751 while (limit < end && is_joiner (info[limit])) 752 limit++; 753 base = start; 754 has_reph = true; 755 } 756 } else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == OT_Repha) 757 { 758 limit += 1; 759 while (limit < end && is_joiner (info[limit])) 760 limit++; 761 base = start; 762 has_reph = true; 763 } 764 765 switch (indic_plan->config->base_pos) 766 { 767 case BASE_POS_LAST: 768 { 769 /* -> starting from the end of the syllable, move backwards */ 770 unsigned int i = end; 771 bool seen_below = false; 772 do { 773 i--; 774 /* -> until a consonant is found */ 775 if (is_consonant (info[i])) 776 { 777 /* -> that does not have a below-base or post-base form 778 * (post-base forms have to follow below-base forms), */ 779 if (info[i].indic_position() != POS_BELOW_C && 780 (info[i].indic_position() != POS_POST_C || seen_below)) 781 { 782 base = i; 783 break; 784 } 785 if (info[i].indic_position() == POS_BELOW_C) 786 seen_below = true; 787 788 /* -> or that is not a pre-base-reordering Ra, 789 * 790 * IMPLEMENTATION NOTES: 791 * 792 * Our pre-base-reordering Ra's are marked POS_POST_C, so will be skipped 793 * by the logic above already. 794 */ 795 796 /* -> or arrive at the first consonant. The consonant stopped at will 797 * be the base. */ 798 base = i; 799 } 800 else 801 { 802 /* A ZWJ after a Halant stops the base search, and requests an explicit 803 * half form. 804 * A ZWJ before a Halant, requests a subjoined form instead, and hence 805 * search continues. This is particularly important for Bengali 806 * sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */ 807 if (start < i && 808 info[i].indic_category() == OT_ZWJ && 809 info[i - 1].indic_category() == OT_H) 810 break; 811 } 812 } while (i > limit); 813 } 814 break; 815 816 case BASE_POS_LAST_SINHALA: 817 { 818 /* Sinhala base positioning is slightly different from main Indic, in that: 819 * 1. Its ZWJ behavior is different, 820 * 2. We don't need to look into the font for consonant positions. 821 */ 822 823 if (!has_reph) 824 base = limit; 825 826 /* Find the last base consonant that is not blocked by ZWJ. If there is 827 * a ZWJ right before a base consonant, that would request a subjoined form. */ 828 for (unsigned int i = limit; i < end; i++) 829 if (is_consonant (info[i])) 830 { 831 if (limit < i && info[i - 1].indic_category() == OT_ZWJ) 832 break; 833 else 834 base = i; 835 } 836 837 /* Mark all subsequent consonants as below. */ 838 for (unsigned int i = base + 1; i < end; i++) 839 if (is_consonant (info[i])) 840 info[i].indic_position() = POS_BELOW_C; 841 } 842 break; 843 844 case BASE_POS_FIRST: 845 { 846 /* The first consonant is always the base. */ 847 848 assert (indic_plan->config->reph_mode == REPH_MODE_VIS_REPHA); 849 assert (!has_reph); 850 851 base = start; 852 853 /* Mark all subsequent consonants as below. */ 854 for (unsigned int i = base + 1; i < end; i++) 855 if (is_consonant (info[i])) 856 info[i].indic_position() = POS_BELOW_C; 857 } 858 break; 859 } 860 861 /* -> If the syllable starts with Ra + Halant (in a script that has Reph) 862 * and has more than one consonant, Ra is excluded from candidates for 863 * base consonants. 864 * 865 * Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */ 866 if (has_reph && base == start && limit - base <= 2) { 867 /* Have no other consonant, so Reph is not formed and Ra becomes base. */ 868 has_reph = false; 869 } 870 } 871 872 873 /* 2. Decompose and reorder Matras: 874 * 875 * Each matra and any syllable modifier sign in the syllable are moved to the 876 * appropriate position relative to the consonant(s) in the syllable. The 877 * shaping engine decomposes two- or three-part matras into their constituent 878 * parts before any repositioning. Matra characters are classified by which 879 * consonant in a conjunct they have affinity for and are reordered to the 880 * following positions: 881 * 882 * o Before first half form in the syllable 883 * o After subjoined consonants 884 * o After post-form consonant 885 * o After main consonant (for above marks) 886 * 887 * IMPLEMENTATION NOTES: 888 * 889 * The normalize() routine has already decomposed matras for us, so we don't 890 * need to worry about that. 891 */ 892 893 894 /* 3. Reorder marks to canonical order: 895 * 896 * Adjacent nukta and halant or nukta and vedic sign are always repositioned 897 * if necessary, so that the nukta is first. 898 * 899 * IMPLEMENTATION NOTES: 900 * 901 * We don't need to do this: the normalize() routine already did this for us. 902 */ 903 904 905 /* Reorder characters */ 906 907 for (unsigned int i = start; i < base; i++) 908 info[i].indic_position() = MIN (POS_PRE_C, (indic_position_t) info[i].indic_position()); 909 910 if (base < end) 911 info[base].indic_position() = POS_BASE_C; 912 913 /* Mark final consonants. A final consonant is one appearing after a matra, 914 * like in Khmer. */ 915 for (unsigned int i = base + 1; i < end; i++) 916 if (info[i].indic_category() == OT_M) { 917 for (unsigned int j = i + 1; j < end; j++) 918 if (is_consonant (info[j])) { 919 info[j].indic_position() = POS_FINAL_C; 920 break; 921 } 922 break; 923 } 924 925 /* Handle beginning Ra */ 926 if (has_reph) 927 info[start].indic_position() = POS_RA_TO_BECOME_REPH; 928 929 /* For old-style Indic script tags, move the first post-base Halant after 930 * last consonant. 931 * 932 * Reports suggest that in some scripts Uniscribe does this only if there 933 * is *not* a Halant after last consonant already (eg. Kannada), while it 934 * does it unconditionally in other scripts (eg. Malayalam). We don't 935 * currently know about other scripts, so we single out Malayalam for now. 936 * 937 * Kannada test case: 938 * U+0C9A,U+0CCD,U+0C9A,U+0CCD 939 * With some versions of Lohit Kannada. 940 * https://bugs.freedesktop.org/show_bug.cgi?id=59118 941 * 942 * Malayalam test case: 943 * U+0D38,U+0D4D,U+0D31,U+0D4D,U+0D31,U+0D4D 944 * With lohit-ttf-20121122/Lohit-Malayalam.ttf 945 */ 946 if (indic_plan->is_old_spec) 947 { 948 bool disallow_double_halants = buffer->props.script != HB_SCRIPT_MALAYALAM; 949 for (unsigned int i = base + 1; i < end; i++) 950 if (info[i].indic_category() == OT_H) 951 { 952 unsigned int j; 953 for (j = end - 1; j > i; j--) 954 if (is_consonant (info[j]) || 955 (disallow_double_halants && info[j].indic_category() == OT_H)) 956 break; 957 if (info[j].indic_category() != OT_H && j > i) { 958 /* Move Halant to after last consonant. */ 959 hb_glyph_info_t t = info[i]; 960 memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0])); 961 info[j] = t; 962 } 963 break; 964 } 965 } 966 967 /* Attach misc marks to previous char to move with them. */ 968 { 969 indic_position_t last_pos = POS_START; 970 for (unsigned int i = start; i < end; i++) 971 { 972 if ((FLAG_UNSAFE (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | MEDIAL_FLAGS | HALANT_OR_COENG_FLAGS))) 973 { 974 info[i].indic_position() = last_pos; 975 if (unlikely (info[i].indic_category() == OT_H && 976 info[i].indic_position() == POS_PRE_M)) 977 { 978 /* 979 * Uniscribe doesn't move the Halant with Left Matra. 980 * TEST: U+092B,U+093F,U+094DE 981 * We follow. This is important for the Sinhala 982 * U+0DDA split matra since it decomposes to U+0DD9,U+0DCA 983 * where U+0DD9 is a left matra and U+0DCA is the virama. 984 * We don't want to move the virama with the left matra. 985 * TEST: U+0D9A,U+0DDA 986 */ 987 for (unsigned int j = i; j > start; j--) 988 if (info[j - 1].indic_position() != POS_PRE_M) { 989 info[i].indic_position() = info[j - 1].indic_position(); 990 break; 991 } 992 } 993 } else if (info[i].indic_position() != POS_SMVD) { 994 last_pos = (indic_position_t) info[i].indic_position(); 995 } 996 } 997 } 998 /* For post-base consonants let them own anything before them 999 * since the last consonant or matra. */ 1000 { 1001 unsigned int last = base; 1002 for (unsigned int i = base + 1; i < end; i++) 1003 if (is_consonant (info[i])) 1004 { 1005 for (unsigned int j = last + 1; j < i; j++) 1006 if (info[j].indic_position() < POS_SMVD) 1007 info[j].indic_position() = info[i].indic_position(); 1008 last = i; 1009 } else if (info[i].indic_category() == OT_M) 1010 last = i; 1011 } 1012 1013 1014 { 1015 /* Use syllable() for sort accounting temporarily. */ 1016 unsigned int syllable = info[start].syllable(); 1017 for (unsigned int i = start; i < end; i++) 1018 info[i].syllable() = i - start; 1019 1020 /* Sit tight, rock 'n roll! */ 1021 hb_stable_sort (info + start, end - start, compare_indic_order); 1022 /* Find base again */ 1023 base = end; 1024 for (unsigned int i = start; i < end; i++) 1025 if (info[i].indic_position() == POS_BASE_C) 1026 { 1027 base = i; 1028 break; 1029 } 1030 /* Things are out-of-control for post base positions, they may shuffle 1031 * around like crazy. In old-spec mode, we move halants around, so in 1032 * that case merge all clusters after base. Otherwise, check the sort 1033 * order and merge as needed. 1034 * For pre-base stuff, we handle cluster issues in final reordering. 1035 * 1036 * We could use buffer->sort() for this, if there was no special 1037 * reordering of pre-base stuff happening later... 1038 */ 1039 if (indic_plan->is_old_spec || end - base > 127) 1040 buffer->merge_clusters (base, end); 1041 else 1042 { 1043 /* Note! syllable() is a one-byte field. */ 1044 for (unsigned int i = base; i < end; i++) 1045 if (info[i].syllable() != 255) 1046 { 1047 unsigned int max = i; 1048 unsigned int j = start + info[i].syllable(); 1049 while (j != i) 1050 { 1051 max = MAX (max, j); 1052 unsigned int next = start + info[j].syllable(); 1053 info[j].syllable() = 255; /* So we don't process j later again. */ 1054 j = next; 1055 } 1056 if (i != max) 1057 buffer->merge_clusters (i, max + 1); 1058 } 1059 } 1060 1061 /* Put syllable back in. */ 1062 for (unsigned int i = start; i < end; i++) 1063 info[i].syllable() = syllable; 1064 } 1065 1066 /* Setup masks now */ 1067 1068 { 1069 hb_mask_t mask; 1070 1071 /* Reph */ 1072 for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++) 1073 info[i].mask |= indic_plan->mask_array[RPHF]; 1074 1075 /* Pre-base */ 1076 mask = indic_plan->mask_array[HALF]; 1077 if (!indic_plan->is_old_spec && 1078 indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST) 1079 mask |= indic_plan->mask_array[BLWF]; 1080 for (unsigned int i = start; i < base; i++) 1081 info[i].mask |= mask; 1082 /* Base */ 1083 mask = 0; 1084 if (base < end) 1085 info[base].mask |= mask; 1086 /* Post-base */ 1087 mask = indic_plan->mask_array[BLWF] | indic_plan->mask_array[ABVF] | indic_plan->mask_array[PSTF]; 1088 for (unsigned int i = base + 1; i < end; i++) 1089 info[i].mask |= mask; 1090 } 1091 1092 if (indic_plan->is_old_spec && 1093 buffer->props.script == HB_SCRIPT_DEVANAGARI) 1094 { 1095 /* Old-spec eye-lash Ra needs special handling. From the 1096 * spec: 1097 * 1098 * "The feature 'below-base form' is applied to consonants 1099 * having below-base forms and following the base consonant. 1100 * The exception is vattu, which may appear below half forms 1101 * as well as below the base glyph. The feature 'below-base 1102 * form' will be applied to all such occurrences of Ra as well." 1103 * 1104 * Test case: U+0924,U+094D,U+0930,U+094d,U+0915 1105 * with Sanskrit 2003 font. 1106 * 1107 * However, note that Ra,Halant,ZWJ is the correct way to 1108 * request eyelash form of Ra, so we wouldbn't inhibit it 1109 * in that sequence. 1110 * 1111 * Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915 1112 */ 1113 for (unsigned int i = start; i + 1 < base; i++) 1114 if (info[i ].indic_category() == OT_Ra && 1115 info[i+1].indic_category() == OT_H && 1116 (i + 2 == base || 1117 info[i+2].indic_category() != OT_ZWJ)) 1118 { 1119 info[i ].mask |= indic_plan->mask_array[BLWF]; 1120 info[i+1].mask |= indic_plan->mask_array[BLWF]; 1121 } 1122 } 1123 1124 unsigned int pref_len = 2; 1125 if (indic_plan->mask_array[PREF] && base + pref_len < end) 1126 { 1127 /* Find a Halant,Ra sequence and mark it for pre-base-reordering processing. */ 1128 for (unsigned int i = base + 1; i + pref_len - 1 < end; i++) { 1129 hb_codepoint_t glyphs[2]; 1130 for (unsigned int j = 0; j < pref_len; j++) 1131 glyphs[j] = info[i + j].codepoint; 1132 if (indic_plan->pref.would_substitute (glyphs, pref_len, face)) 1133 { 1134 for (unsigned int j = 0; j < pref_len; j++) 1135 info[i++].mask |= indic_plan->mask_array[PREF]; 1136 1137 /* Mark the subsequent stuff with 'cfar'. Used in Khmer. 1138 * Read the feature spec. 1139 * This allows distinguishing the following cases with MS Khmer fonts: 1140 * U+1784,U+17D2,U+179A,U+17D2,U+1782 1141 * U+1784,U+17D2,U+1782,U+17D2,U+179A 1142 */ 1143 if (indic_plan->mask_array[CFAR]) 1144 for (; i < end; i++) 1145 info[i].mask |= indic_plan->mask_array[CFAR]; 1146 1147 break; 1148 } 1149 } 1150 } 1151 1152 /* Apply ZWJ/ZWNJ effects */ 1153 for (unsigned int i = start + 1; i < end; i++) 1154 if (is_joiner (info[i])) { 1155 bool non_joiner = info[i].indic_category() == OT_ZWNJ; 1156 unsigned int j = i; 1157 1158 do { 1159 j--; 1160 1161 /* ZWJ/ZWNJ should disable CJCT. They do that by simply 1162 * being there, since we don't skip them for the CJCT 1163 * feature (ie. F_MANUAL_ZWJ) */ 1164 1165 /* A ZWNJ disables HALF. */ 1166 if (non_joiner) 1167 info[j].mask &= ~indic_plan->mask_array[HALF]; 1168 1169 } while (j > start && !is_consonant (info[j])); 1170 } 1171 } 1172 1173 static void 1174 initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan, 1175 hb_face_t *face, 1176 hb_buffer_t *buffer, 1177 unsigned int start, unsigned int end) 1178 { 1179 /* We treat placeholder/dotted-circle as if they are consonants, so we 1180 * should just chain. Only if not in compatibility mode that is... */ 1181 1182 if (hb_options ().uniscribe_bug_compatible) 1183 { 1184 /* For dotted-circle, this is what Uniscribe does: 1185 * If dotted-circle is the last glyph, it just does nothing. 1186 * Ie. It doesn't form Reph. */ 1187 if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE) 1188 return; 1189 } 1190 1191 initial_reordering_consonant_syllable (plan, face, buffer, start, end); 1192 } 1193 1194 static void 1195 initial_reordering_syllable (const hb_ot_shape_plan_t *plan, 1196 hb_face_t *face, 1197 hb_buffer_t *buffer, 1198 unsigned int start, unsigned int end) 1199 { 1200 syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F); 1201 switch (syllable_type) 1202 { 1203 case vowel_syllable: /* We made the vowels look like consonants. So let's call the consonant logic! */ 1204 case consonant_syllable: 1205 initial_reordering_consonant_syllable (plan, face, buffer, start, end); 1206 break; 1207 1208 case broken_cluster: /* We already inserted dotted-circles, so just call the standalone_cluster. */ 1209 case standalone_cluster: 1210 initial_reordering_standalone_cluster (plan, face, buffer, start, end); 1211 break; 1212 1213 case symbol_cluster: 1214 case non_indic_cluster: 1215 break; 1216 } 1217 } 1218 1219 static inline void 1220 insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED, 1221 hb_font_t *font, 1222 hb_buffer_t *buffer) 1223 { 1224 /* Note: This loop is extra overhead, but should not be measurable. */ 1225 bool has_broken_syllables = false; 1226 unsigned int count = buffer->len; 1227 hb_glyph_info_t *info = buffer->info; 1228 for (unsigned int i = 0; i < count; i++) 1229 if ((info[i].syllable() & 0x0F) == broken_cluster) 1230 { 1231 has_broken_syllables = true; 1232 break; 1233 } 1234 if (likely (!has_broken_syllables)) 1235 return; 1236 1237 1238 hb_codepoint_t dottedcircle_glyph; 1239 if (!font->get_nominal_glyph (0x25CCu, &dottedcircle_glyph)) 1240 return; 1241 1242 hb_glyph_info_t dottedcircle = {0}; 1243 dottedcircle.codepoint = 0x25CCu; 1244 set_indic_properties (dottedcircle); 1245 dottedcircle.codepoint = dottedcircle_glyph; 1246 1247 buffer->clear_output (); 1248 1249 buffer->idx = 0; 1250 unsigned int last_syllable = 0; 1251 while (buffer->idx < buffer->len && !buffer->in_error) 1252 { 1253 unsigned int syllable = buffer->cur().syllable(); 1254 syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F); 1255 if (unlikely (last_syllable != syllable && syllable_type == broken_cluster)) 1256 { 1257 last_syllable = syllable; 1258 1259 hb_glyph_info_t ginfo = dottedcircle; 1260 ginfo.cluster = buffer->cur().cluster; 1261 ginfo.mask = buffer->cur().mask; 1262 ginfo.syllable() = buffer->cur().syllable(); 1263 /* TODO Set glyph_props? */ 1264 1265 /* Insert dottedcircle after possible Repha. */ 1266 while (buffer->idx < buffer->len && !buffer->in_error && 1267 last_syllable == buffer->cur().syllable() && 1268 buffer->cur().indic_category() == OT_Repha) 1269 buffer->next_glyph (); 1270 1271 buffer->output_info (ginfo); 1272 } 1273 else 1274 buffer->next_glyph (); 1275 } 1276 1277 buffer->swap_buffers (); 1278 } 1279 1280 static void 1281 initial_reordering (const hb_ot_shape_plan_t *plan, 1282 hb_font_t *font, 1283 hb_buffer_t *buffer) 1284 { 1285 update_consonant_positions (plan, font, buffer); 1286 insert_dotted_circles (plan, font, buffer); 1287 1288 foreach_syllable (buffer, start, end) 1289 initial_reordering_syllable (plan, font->face, buffer, start, end); 1290 } 1291 1292 static void 1293 final_reordering_syllable (const hb_ot_shape_plan_t *plan, 1294 hb_buffer_t *buffer, 1295 unsigned int start, unsigned int end) 1296 { 1297 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; 1298 hb_glyph_info_t *info = buffer->info; 1299 1300 1301 /* This function relies heavily on halant glyphs. Lots of ligation 1302 * and possibly multiple substitutions happened prior to this 1303 * phase, and that might have messed up our properties. Recover 1304 * from a particular case of that where we're fairly sure that a 1305 * class of OT_H is desired but has been lost. */ 1306 if (indic_plan->virama_glyph) 1307 { 1308 unsigned int virama_glyph = indic_plan->virama_glyph; 1309 for (unsigned int i = start; i < end; i++) 1310 if (info[i].codepoint == virama_glyph && 1311 _hb_glyph_info_ligated (&info[i]) && 1312 _hb_glyph_info_multiplied (&info[i])) 1313 { 1314 /* This will make sure that this glyph passes is_halant_or_coeng() test. */ 1315 info[i].indic_category() = OT_H; 1316 _hb_glyph_info_clear_ligated_and_multiplied (&info[i]); 1317 } 1318 } 1319 1320 1321 /* 4. Final reordering: 1322 * 1323 * After the localized forms and basic shaping forms GSUB features have been 1324 * applied (see below), the shaping engine performs some final glyph 1325 * reordering before applying all the remaining font features to the entire 1326 * syllable. 1327 */ 1328 1329 bool try_pref = !!indic_plan->mask_array[PREF]; 1330 1331 /* Find base again */ 1332 unsigned int base; 1333 for (base = start; base < end; base++) 1334 if (info[base].indic_position() >= POS_BASE_C) 1335 { 1336 if (try_pref && base + 1 < end) 1337 { 1338 for (unsigned int i = base + 1; i < end; i++) 1339 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0) 1340 { 1341 if (!(_hb_glyph_info_substituted (&info[i]) && 1342 _hb_glyph_info_ligated_and_didnt_multiply (&info[i]))) 1343 { 1344 /* Ok, this was a 'pref' candidate but didn't form any. 1345 * Base is around here... */ 1346 base = i; 1347 while (base < end && is_halant_or_coeng (info[base])) 1348 base++; 1349 info[base].indic_position() = POS_BASE_C; 1350 1351 try_pref = false; 1352 } 1353 break; 1354 } 1355 } 1356 /* For Malayalam, skip over unformed below- (but NOT post-) forms. */ 1357 if (buffer->props.script == HB_SCRIPT_MALAYALAM) 1358 { 1359 for (unsigned int i = base + 1; i < end; i++) 1360 { 1361 while (i < end && is_joiner (info[i])) 1362 i++; 1363 if (i == end || !is_halant_or_coeng (info[i])) 1364 break; 1365 i++; /* Skip halant. */ 1366 while (i < end && is_joiner (info[i])) 1367 i++; 1368 if (i < end && is_consonant (info[i]) && info[i].indic_position() == POS_BELOW_C) 1369 { 1370 base = i; 1371 info[base].indic_position() = POS_BASE_C; 1372 } 1373 } 1374 } 1375 1376 if (start < base && info[base].indic_position() > POS_BASE_C) 1377 base--; 1378 break; 1379 } 1380 if (base == end && start < base && 1381 is_one_of (info[base - 1], FLAG (OT_ZWJ))) 1382 base--; 1383 if (base < end) 1384 while (start < base && 1385 is_one_of (info[base], (FLAG (OT_N) | HALANT_OR_COENG_FLAGS))) 1386 base--; 1387 1388 1389 /* o Reorder matras: 1390 * 1391 * If a pre-base matra character had been reordered before applying basic 1392 * features, the glyph can be moved closer to the main consonant based on 1393 * whether half-forms had been formed. Actual position for the matra is 1394 * defined as after last standalone halant glyph, after initial matra 1395 * position and before the main consonant. If ZWJ or ZWNJ follow this 1396 * halant, position is moved after it. 1397 */ 1398 1399 if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */ 1400 { 1401 /* If we lost track of base, alas, position before last thingy. */ 1402 unsigned int new_pos = base == end ? base - 2 : base - 1; 1403 1404 /* Malayalam / Tamil do not have "half" forms or explicit virama forms. 1405 * The glyphs formed by 'half' are Chillus or ligated explicit viramas. 1406 * We want to position matra after them. 1407 */ 1408 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL) 1409 { 1410 while (new_pos > start && 1411 !(is_one_of (info[new_pos], (FLAG (OT_M) | HALANT_OR_COENG_FLAGS)))) 1412 new_pos--; 1413 1414 /* If we found no Halant we are done. 1415 * Otherwise only proceed if the Halant does 1416 * not belong to the Matra itself! */ 1417 if (is_halant_or_coeng (info[new_pos]) && 1418 info[new_pos].indic_position() != POS_PRE_M) 1419 { 1420 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */ 1421 if (new_pos + 1 < end && is_joiner (info[new_pos + 1])) 1422 new_pos++; 1423 } 1424 else 1425 new_pos = start; /* No move. */ 1426 } 1427 1428 if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M) 1429 { 1430 /* Now go see if there's actually any matras... */ 1431 for (unsigned int i = new_pos; i > start; i--) 1432 if (info[i - 1].indic_position () == POS_PRE_M) 1433 { 1434 unsigned int old_pos = i - 1; 1435 if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */ 1436 base--; 1437 1438 hb_glyph_info_t tmp = info[old_pos]; 1439 memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0])); 1440 info[new_pos] = tmp; 1441 1442 /* Note: this merge_clusters() is intentionally *after* the reordering. 1443 * Indic matra reordering is special and tricky... */ 1444 buffer->merge_clusters (new_pos, MIN (end, base + 1)); 1445 1446 new_pos--; 1447 } 1448 } else { 1449 for (unsigned int i = start; i < base; i++) 1450 if (info[i].indic_position () == POS_PRE_M) { 1451 buffer->merge_clusters (i, MIN (end, base + 1)); 1452 break; 1453 } 1454 } 1455 } 1456 1457 1458 /* o Reorder reph: 1459 * 1460 * Rephs original position is always at the beginning of the syllable, 1461 * (i.e. it is not reordered at the character reordering stage). However, 1462 * it will be reordered according to the basic-forms shaping results. 1463 * Possible positions for reph, depending on the script, are; after main, 1464 * before post-base consonant forms, and after post-base consonant forms. 1465 */ 1466 1467 /* Two cases: 1468 * 1469 * - If repha is encoded as a sequence of characters (Ra,H or Ra,H,ZWJ), then 1470 * we should only move it if the sequence ligated to the repha form. 1471 * 1472 * - If repha is encoded separately and in the logical position, we should only 1473 * move it if it did NOT ligate. If it ligated, it's probably the font trying 1474 * to make it work without the reordering. 1475 */ 1476 if (start + 1 < end && 1477 info[start].indic_position() == POS_RA_TO_BECOME_REPH && 1478 ((info[start].indic_category() == OT_Repha) ^ 1479 _hb_glyph_info_ligated_and_didnt_multiply (&info[start]))) 1480 { 1481 unsigned int new_reph_pos; 1482 reph_position_t reph_pos = indic_plan->config->reph_pos; 1483 1484 assert (reph_pos != REPH_POS_DONT_CARE); 1485 1486 /* 1. If reph should be positioned after post-base consonant forms, 1487 * proceed to step 5. 1488 */ 1489 if (reph_pos == REPH_POS_AFTER_POST) 1490 { 1491 goto reph_step_5; 1492 } 1493 1494 /* 2. If the reph repositioning class is not after post-base: target 1495 * position is after the first explicit halant glyph between the 1496 * first post-reph consonant and last main consonant. If ZWJ or ZWNJ 1497 * are following this halant, position is moved after it. If such 1498 * position is found, this is the target position. Otherwise, 1499 * proceed to the next step. 1500 * 1501 * Note: in old-implementation fonts, where classifications were 1502 * fixed in shaping engine, there was no case where reph position 1503 * will be found on this step. 1504 */ 1505 { 1506 new_reph_pos = start + 1; 1507 while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos])) 1508 new_reph_pos++; 1509 1510 if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos])) 1511 { 1512 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */ 1513 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1])) 1514 new_reph_pos++; 1515 goto reph_move; 1516 } 1517 } 1518 1519 /* 3. If reph should be repositioned after the main consonant: find the 1520 * first consonant not ligated with main, or find the first 1521 * consonant that is not a potential pre-base-reordering Ra. 1522 */ 1523 if (reph_pos == REPH_POS_AFTER_MAIN) 1524 { 1525 new_reph_pos = base; 1526 while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN) 1527 new_reph_pos++; 1528 if (new_reph_pos < end) 1529 goto reph_move; 1530 } 1531 1532 /* 4. If reph should be positioned before post-base consonant, find 1533 * first post-base classified consonant not ligated with main. If no 1534 * consonant is found, the target position should be before the 1535 * first matra, syllable modifier sign or vedic sign. 1536 */ 1537 /* This is our take on what step 4 is trying to say (and failing, BADLY). */ 1538 if (reph_pos == REPH_POS_AFTER_SUB) 1539 { 1540 new_reph_pos = base; 1541 while (new_reph_pos + 1 < end && 1542 !( FLAG_UNSAFE (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD)))) 1543 new_reph_pos++; 1544 if (new_reph_pos < end) 1545 goto reph_move; 1546 } 1547 1548 /* 5. If no consonant is found in steps 3 or 4, move reph to a position 1549 * immediately before the first post-base matra, syllable modifier 1550 * sign or vedic sign that has a reordering class after the intended 1551 * reph position. For example, if the reordering position for reph 1552 * is post-main, it will skip above-base matras that also have a 1553 * post-main position. 1554 */ 1555 reph_step_5: 1556 { 1557 /* Copied from step 2. */ 1558 new_reph_pos = start + 1; 1559 while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos])) 1560 new_reph_pos++; 1561 1562 if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos])) 1563 { 1564 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */ 1565 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1])) 1566 new_reph_pos++; 1567 goto reph_move; 1568 } 1569 } 1570 1571 /* 6. Otherwise, reorder reph to the end of the syllable. 1572 */ 1573 { 1574 new_reph_pos = end - 1; 1575 while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD) 1576 new_reph_pos--; 1577 1578 /* 1579 * If the Reph is to be ending up after a Matra,Halant sequence, 1580 * position it before that Halant so it can interact with the Matra. 1581 * However, if it's a plain Consonant,Halant we shouldn't do that. 1582 * Uniscribe doesn't do this. 1583 * TEST: U+0930,U+094D,U+0915,U+094B,U+094D 1584 */ 1585 if (!hb_options ().uniscribe_bug_compatible && 1586 unlikely (is_halant_or_coeng (info[new_reph_pos]))) { 1587 for (unsigned int i = base + 1; i < new_reph_pos; i++) 1588 if (info[i].indic_category() == OT_M) { 1589 /* Ok, got it. */ 1590 new_reph_pos--; 1591 } 1592 } 1593 goto reph_move; 1594 } 1595 1596 reph_move: 1597 { 1598 /* Move */ 1599 buffer->merge_clusters (start, new_reph_pos + 1); 1600 hb_glyph_info_t reph = info[start]; 1601 memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0])); 1602 info[new_reph_pos] = reph; 1603 1604 if (start < base && base <= new_reph_pos) 1605 base--; 1606 } 1607 } 1608 1609 1610 /* o Reorder pre-base-reordering consonants: 1611 * 1612 * If a pre-base-reordering consonant is found, reorder it according to 1613 * the following rules: 1614 */ 1615 1616 if (try_pref && base + 1 < end) /* Otherwise there can't be any pre-base-reordering Ra. */ 1617 { 1618 for (unsigned int i = base + 1; i < end; i++) 1619 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0) 1620 { 1621 /* 1. Only reorder a glyph produced by substitution during application 1622 * of the <pref> feature. (Note that a font may shape a Ra consonant with 1623 * the feature generally but block it in certain contexts.) 1624 */ 1625 /* Note: We just check that something got substituted. We don't check that 1626 * the <pref> feature actually did it... 1627 * 1628 * Reorder pref only if it ligated. */ 1629 if (_hb_glyph_info_ligated_and_didnt_multiply (&info[i])) 1630 { 1631 /* 1632 * 2. Try to find a target position the same way as for pre-base matra. 1633 * If it is found, reorder pre-base consonant glyph. 1634 * 1635 * 3. If position is not found, reorder immediately before main 1636 * consonant. 1637 */ 1638 1639 unsigned int new_pos = base; 1640 /* Malayalam / Tamil do not have "half" forms or explicit virama forms. 1641 * The glyphs formed by 'half' are Chillus or ligated explicit viramas. 1642 * We want to position matra after them. 1643 */ 1644 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL) 1645 { 1646 while (new_pos > start && 1647 !(is_one_of (info[new_pos - 1], FLAG(OT_M) | HALANT_OR_COENG_FLAGS))) 1648 new_pos--; 1649 1650 /* In Khmer coeng model, a H,Ra can go *after* matras. If it goes after a 1651 * split matra, it should be reordered to *before* the left part of such matra. */ 1652 if (new_pos > start && info[new_pos - 1].indic_category() == OT_M) 1653 { 1654 unsigned int old_pos = i; 1655 for (unsigned int j = base + 1; j < old_pos; j++) 1656 if (info[j].indic_category() == OT_M) 1657 { 1658 new_pos--; 1659 break; 1660 } 1661 } 1662 } 1663 1664 if (new_pos > start && is_halant_or_coeng (info[new_pos - 1])) 1665 { 1666 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */ 1667 if (new_pos < end && is_joiner (info[new_pos])) 1668 new_pos++; 1669 } 1670 1671 { 1672 unsigned int old_pos = i; 1673 1674 buffer->merge_clusters (new_pos, old_pos + 1); 1675 hb_glyph_info_t tmp = info[old_pos]; 1676 memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0])); 1677 info[new_pos] = tmp; 1678 1679 if (new_pos <= base && base < old_pos) 1680 base++; 1681 } 1682 } 1683 1684 break; 1685 } 1686 } 1687 1688 1689 /* Apply 'init' to the Left Matra if it's a word start. */ 1690 if (info[start].indic_position () == POS_PRE_M) 1691 { 1692 if (!start || 1693 !(FLAG_UNSAFE (_hb_glyph_info_get_general_category (&info[start - 1])) & 1694 FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK))) 1695 info[start].mask |= indic_plan->mask_array[INIT]; 1696 else 1697 buffer->unsafe_to_break (start - 1, start + 1); 1698 } 1699 1700 1701 /* 1702 * Finish off the clusters and go home! 1703 */ 1704 if (hb_options ().uniscribe_bug_compatible) 1705 { 1706 switch ((hb_tag_t) plan->props.script) 1707 { 1708 case HB_SCRIPT_TAMIL: 1709 case HB_SCRIPT_SINHALA: 1710 break; 1711 1712 default: 1713 /* Uniscribe merges the entire syllable into a single cluster... Except for Tamil & Sinhala. 1714 * This means, half forms are submerged into the main consonant's cluster. 1715 * This is unnecessary, and makes cursor positioning harder, but that's what 1716 * Uniscribe does. */ 1717 buffer->merge_clusters (start, end); 1718 break; 1719 } 1720 } 1721 } 1722 1723 1724 static void 1725 final_reordering (const hb_ot_shape_plan_t *plan, 1726 hb_font_t *font HB_UNUSED, 1727 hb_buffer_t *buffer) 1728 { 1729 unsigned int count = buffer->len; 1730 if (unlikely (!count)) return; 1731 1732 foreach_syllable (buffer, start, end) 1733 final_reordering_syllable (plan, buffer, start, end); 1734 1735 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category); 1736 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position); 1737 } 1738 1739 1740 static void 1741 clear_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED, 1742 hb_font_t *font HB_UNUSED, 1743 hb_buffer_t *buffer) 1744 { 1745 hb_glyph_info_t *info = buffer->info; 1746 unsigned int count = buffer->len; 1747 for (unsigned int i = 0; i < count; i++) 1748 info[i].syllable() = 0; 1749 } 1750 1751 1752 static bool 1753 decompose_indic (const hb_ot_shape_normalize_context_t *c, 1754 hb_codepoint_t ab, 1755 hb_codepoint_t *a, 1756 hb_codepoint_t *b) 1757 { 1758 switch (ab) 1759 { 1760 /* Don't decompose these. */ 1761 case 0x0931u : return false; /* DEVANAGARI LETTER RRA */ 1762 case 0x0B94u : return false; /* TAMIL LETTER AU */ 1763 1764 1765 /* 1766 * Decompose split matras that don't have Unicode decompositions. 1767 */ 1768 1769 /* Khmer */ 1770 case 0x17BEu : *a = 0x17C1u; *b= 0x17BEu; return true; 1771 case 0x17BFu : *a = 0x17C1u; *b= 0x17BFu; return true; 1772 case 0x17C0u : *a = 0x17C1u; *b= 0x17C0u; return true; 1773 case 0x17C4u : *a = 0x17C1u; *b= 0x17C4u; return true; 1774 case 0x17C5u : *a = 0x17C1u; *b= 0x17C5u; return true; 1775 1776 #if 0 1777 /* Gujarati */ 1778 /* This one has no decomposition in Unicode, but needs no decomposition either. */ 1779 /* case 0x0AC9u : return false; */ 1780 1781 /* Oriya */ 1782 case 0x0B57u : *a = no decomp, -> RIGHT; return true; 1783 #endif 1784 } 1785 1786 if ((ab == 0x0DDAu || hb_in_range<hb_codepoint_t> (ab, 0x0DDCu, 0x0DDEu))) 1787 { 1788 /* 1789 * Sinhala split matras... Let the fun begin. 1790 * 1791 * These four characters have Unicode decompositions. However, Uniscribe 1792 * decomposes them "Khmer-style", that is, it uses the character itself to 1793 * get the second half. The first half of all four decompositions is always 1794 * U+0DD9. 1795 * 1796 * Now, there are buggy fonts, namely, the widely used lklug.ttf, that are 1797 * broken with Uniscribe. But we need to support them. As such, we only 1798 * do the Uniscribe-style decomposition if the character is transformed into 1799 * its "sec.half" form by the 'pstf' feature. Otherwise, we fall back to 1800 * Unicode decomposition. 1801 * 1802 * Note that we can't unconditionally use Unicode decomposition. That would 1803 * break some other fonts, that are designed to work with Uniscribe, and 1804 * don't have positioning features for the Unicode-style decomposition. 1805 * 1806 * Argh... 1807 * 1808 * The Uniscribe behavior is now documented in the newly published Sinhala 1809 * spec in 2012: 1810 * 1811 * http://www.microsoft.com/typography/OpenTypeDev/sinhala/intro.htm#shaping 1812 */ 1813 1814 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data; 1815 1816 hb_codepoint_t glyph; 1817 1818 if (hb_options ().uniscribe_bug_compatible || 1819 (c->font->get_nominal_glyph (ab, &glyph) && 1820 indic_plan->pstf.would_substitute (&glyph, 1, c->font->face))) 1821 { 1822 /* Ok, safe to use Uniscribe-style decomposition. */ 1823 *a = 0x0DD9u; 1824 *b = ab; 1825 return true; 1826 } 1827 } 1828 1829 return (bool) c->unicode->decompose (ab, a, b); 1830 } 1831 1832 static bool 1833 compose_indic (const hb_ot_shape_normalize_context_t *c, 1834 hb_codepoint_t a, 1835 hb_codepoint_t b, 1836 hb_codepoint_t *ab) 1837 { 1838 /* Avoid recomposing split matras. */ 1839 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a))) 1840 return false; 1841 1842 /* Composition-exclusion exceptions that we want to recompose. */ 1843 if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; } 1844 1845 return (bool) c->unicode->compose (a, b, ab); 1846 } 1847 1848 1849 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic = 1850 { 1851 collect_features_indic, 1852 override_features_indic, 1853 data_create_indic, 1854 data_destroy_indic, 1855 nullptr, /* preprocess_text */ 1856 nullptr, /* postprocess_glyphs */ 1857 HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT, 1858 decompose_indic, 1859 compose_indic, 1860 setup_masks_indic, 1861 nullptr, /* disable_otl */ 1862 nullptr, /* reorder_marks */ 1863 HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE, 1864 false, /* fallback_position */ 1865 }; 1866
