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-fallback-private.hh" 28 #include "hb-ot-layout-gsubgpos-private.hh" 29 30 static unsigned int 31 recategorize_combining_class (hb_codepoint_t u, 32 unsigned int klass) 33 { 34 if (klass >= 200) 35 return klass; 36 37 /* Thai / Lao need some per-character work. */ 38 if ((u & ~0xFF) == 0x0E00u) 39 { 40 if (unlikely (klass == 0)) 41 { 42 switch (u) 43 { 44 case 0x0E31u: 45 case 0x0E34u: 46 case 0x0E35u: 47 case 0x0E36u: 48 case 0x0E37u: 49 case 0x0E47u: 50 case 0x0E4Cu: 51 case 0x0E4Du: 52 case 0x0E4Eu: 53 klass = HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT; 54 break; 55 56 case 0x0EB1u: 57 case 0x0EB4u: 58 case 0x0EB5u: 59 case 0x0EB6u: 60 case 0x0EB7u: 61 case 0x0EBBu: 62 case 0x0ECCu: 63 case 0x0ECDu: 64 klass = HB_UNICODE_COMBINING_CLASS_ABOVE; 65 break; 66 67 case 0x0EBCu: 68 klass = HB_UNICODE_COMBINING_CLASS_BELOW; 69 break; 70 } 71 } else { 72 /* Thai virama is below-right */ 73 if (u == 0x0E3Au) 74 klass = HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT; 75 } 76 } 77 78 switch (klass) 79 { 80 81 /* Hebrew */ 82 83 case HB_MODIFIED_COMBINING_CLASS_CCC10: /* sheva */ 84 case HB_MODIFIED_COMBINING_CLASS_CCC11: /* hataf segol */ 85 case HB_MODIFIED_COMBINING_CLASS_CCC12: /* hataf patah */ 86 case HB_MODIFIED_COMBINING_CLASS_CCC13: /* hataf qamats */ 87 case HB_MODIFIED_COMBINING_CLASS_CCC14: /* hiriq */ 88 case HB_MODIFIED_COMBINING_CLASS_CCC15: /* tsere */ 89 case HB_MODIFIED_COMBINING_CLASS_CCC16: /* segol */ 90 case HB_MODIFIED_COMBINING_CLASS_CCC17: /* patah */ 91 case HB_MODIFIED_COMBINING_CLASS_CCC18: /* qamats */ 92 case HB_MODIFIED_COMBINING_CLASS_CCC20: /* qubuts */ 93 case HB_MODIFIED_COMBINING_CLASS_CCC22: /* meteg */ 94 return HB_UNICODE_COMBINING_CLASS_BELOW; 95 96 case HB_MODIFIED_COMBINING_CLASS_CCC23: /* rafe */ 97 return HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE; 98 99 case HB_MODIFIED_COMBINING_CLASS_CCC24: /* shin dot */ 100 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT; 101 102 case HB_MODIFIED_COMBINING_CLASS_CCC25: /* sin dot */ 103 case HB_MODIFIED_COMBINING_CLASS_CCC19: /* holam */ 104 return HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT; 105 106 case HB_MODIFIED_COMBINING_CLASS_CCC26: /* point varika */ 107 return HB_UNICODE_COMBINING_CLASS_ABOVE; 108 109 case HB_MODIFIED_COMBINING_CLASS_CCC21: /* dagesh */ 110 break; 111 112 113 /* Arabic and Syriac */ 114 115 case HB_MODIFIED_COMBINING_CLASS_CCC27: /* fathatan */ 116 case HB_MODIFIED_COMBINING_CLASS_CCC28: /* dammatan */ 117 case HB_MODIFIED_COMBINING_CLASS_CCC30: /* fatha */ 118 case HB_MODIFIED_COMBINING_CLASS_CCC31: /* damma */ 119 case HB_MODIFIED_COMBINING_CLASS_CCC33: /* shadda */ 120 case HB_MODIFIED_COMBINING_CLASS_CCC34: /* sukun */ 121 case HB_MODIFIED_COMBINING_CLASS_CCC35: /* superscript alef */ 122 case HB_MODIFIED_COMBINING_CLASS_CCC36: /* superscript alaph */ 123 return HB_UNICODE_COMBINING_CLASS_ABOVE; 124 125 case HB_MODIFIED_COMBINING_CLASS_CCC29: /* kasratan */ 126 case HB_MODIFIED_COMBINING_CLASS_CCC32: /* kasra */ 127 return HB_UNICODE_COMBINING_CLASS_BELOW; 128 129 130 /* Thai */ 131 132 case HB_MODIFIED_COMBINING_CLASS_CCC103: /* sara u / sara uu */ 133 return HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT; 134 135 case HB_MODIFIED_COMBINING_CLASS_CCC107: /* mai */ 136 return HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT; 137 138 139 /* Lao */ 140 141 case HB_MODIFIED_COMBINING_CLASS_CCC118: /* sign u / sign uu */ 142 return HB_UNICODE_COMBINING_CLASS_BELOW; 143 144 case HB_MODIFIED_COMBINING_CLASS_CCC122: /* mai */ 145 return HB_UNICODE_COMBINING_CLASS_ABOVE; 146 147 148 /* Tibetan */ 149 150 case HB_MODIFIED_COMBINING_CLASS_CCC129: /* sign aa */ 151 return HB_UNICODE_COMBINING_CLASS_BELOW; 152 153 case HB_MODIFIED_COMBINING_CLASS_CCC130: /* sign i*/ 154 return HB_UNICODE_COMBINING_CLASS_ABOVE; 155 156 case HB_MODIFIED_COMBINING_CLASS_CCC132: /* sign u */ 157 return HB_UNICODE_COMBINING_CLASS_BELOW; 158 159 } 160 161 return klass; 162 } 163 164 void 165 _hb_ot_shape_fallback_position_recategorize_marks (const hb_ot_shape_plan_t *plan HB_UNUSED, 166 hb_font_t *font HB_UNUSED, 167 hb_buffer_t *buffer) 168 { 169 unsigned int count = buffer->len; 170 hb_glyph_info_t *info = buffer->info; 171 for (unsigned int i = 0; i < count; i++) 172 if (_hb_glyph_info_get_general_category (&info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) { 173 unsigned int combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]); 174 combining_class = recategorize_combining_class (info[i].codepoint, combining_class); 175 _hb_glyph_info_set_modified_combining_class (&info[i], combining_class); 176 } 177 } 178 179 180 static void 181 zero_mark_advances (hb_buffer_t *buffer, 182 unsigned int start, 183 unsigned int end) 184 { 185 hb_glyph_info_t *info = buffer->info; 186 for (unsigned int i = start; i < end; i++) 187 if (_hb_glyph_info_get_general_category (&info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) 188 { 189 buffer->pos[i].x_advance = 0; 190 buffer->pos[i].y_advance = 0; 191 } 192 } 193 194 static inline void 195 position_mark (const hb_ot_shape_plan_t *plan, 196 hb_font_t *font, 197 hb_buffer_t *buffer, 198 hb_glyph_extents_t &base_extents, 199 unsigned int i, 200 unsigned int combining_class) 201 { 202 hb_glyph_extents_t mark_extents; 203 if (!font->get_glyph_extents (buffer->info[i].codepoint, 204 &mark_extents)) 205 return; 206 207 hb_position_t y_gap = font->y_scale / 16; 208 209 hb_glyph_position_t &pos = buffer->pos[i]; 210 pos.x_offset = pos.y_offset = 0; 211 212 213 /* We don't position LEFT and RIGHT marks. */ 214 215 /* X positioning */ 216 switch (combining_class) 217 { 218 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW: 219 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE: 220 if (buffer->props.direction == HB_DIRECTION_LTR) { 221 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing; 222 break; 223 } else if (buffer->props.direction == HB_DIRECTION_RTL) { 224 pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing; 225 break; 226 } 227 HB_FALLTHROUGH; 228 229 default: 230 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW: 231 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE: 232 case HB_UNICODE_COMBINING_CLASS_BELOW: 233 case HB_UNICODE_COMBINING_CLASS_ABOVE: 234 /* Center align. */ 235 pos.x_offset += base_extents.x_bearing + (base_extents.width - mark_extents.width) / 2 - mark_extents.x_bearing; 236 break; 237 238 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT: 239 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT: 240 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT: 241 /* Left align. */ 242 pos.x_offset += base_extents.x_bearing - mark_extents.x_bearing; 243 break; 244 245 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT: 246 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT: 247 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT: 248 /* Right align. */ 249 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width - mark_extents.x_bearing; 250 break; 251 } 252 253 /* Y positioning */ 254 switch (combining_class) 255 { 256 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW: 257 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT: 258 case HB_UNICODE_COMBINING_CLASS_BELOW: 259 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT: 260 /* Add gap, fall-through. */ 261 base_extents.height -= y_gap; 262 HB_FALLTHROUGH; 263 264 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT: 265 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW: 266 pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing; 267 /* Never shift up "below" marks. */ 268 if ((y_gap > 0) == (pos.y_offset > 0)) 269 { 270 base_extents.height -= pos.y_offset; 271 pos.y_offset = 0; 272 } 273 base_extents.height += mark_extents.height; 274 break; 275 276 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE: 277 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT: 278 case HB_UNICODE_COMBINING_CLASS_ABOVE: 279 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT: 280 /* Add gap, fall-through. */ 281 base_extents.y_bearing += y_gap; 282 base_extents.height -= y_gap; 283 HB_FALLTHROUGH; 284 285 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE: 286 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT: 287 pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height); 288 /* Don't shift down "above" marks too much. */ 289 if ((y_gap > 0) != (pos.y_offset > 0)) 290 { 291 unsigned int correction = -pos.y_offset / 2; 292 base_extents.y_bearing += correction; 293 base_extents.height -= correction; 294 pos.y_offset += correction; 295 } 296 base_extents.y_bearing -= mark_extents.height; 297 base_extents.height += mark_extents.height; 298 break; 299 } 300 } 301 302 static inline void 303 position_around_base (const hb_ot_shape_plan_t *plan, 304 hb_font_t *font, 305 hb_buffer_t *buffer, 306 unsigned int base, 307 unsigned int end) 308 { 309 hb_direction_t horiz_dir = HB_DIRECTION_INVALID; 310 311 buffer->unsafe_to_break (base, end); 312 313 hb_glyph_extents_t base_extents; 314 if (!font->get_glyph_extents (buffer->info[base].codepoint, 315 &base_extents)) 316 { 317 /* If extents don't work, zero marks and go home. */ 318 zero_mark_advances (buffer, base + 1, end); 319 return; 320 } 321 base_extents.x_bearing += buffer->pos[base].x_offset; 322 base_extents.y_bearing += buffer->pos[base].y_offset; 323 324 unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]); 325 unsigned int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]); 326 327 hb_position_t x_offset = 0, y_offset = 0; 328 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 329 x_offset -= buffer->pos[base].x_advance; 330 y_offset -= buffer->pos[base].y_advance; 331 } 332 333 hb_glyph_extents_t component_extents = base_extents; 334 unsigned int last_lig_component = (unsigned int) -1; 335 unsigned int last_combining_class = 255; 336 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */ 337 hb_glyph_info_t *info = buffer->info; 338 for (unsigned int i = base + 1; i < end; i++) 339 if (_hb_glyph_info_get_modified_combining_class (&info[i])) 340 { 341 if (num_lig_components > 1) { 342 unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&info[i]); 343 unsigned int this_lig_component = _hb_glyph_info_get_lig_comp (&info[i]) - 1; 344 /* Conditions for attaching to the last component. */ 345 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components) 346 this_lig_component = num_lig_components - 1; 347 if (last_lig_component != this_lig_component) 348 { 349 last_lig_component = this_lig_component; 350 last_combining_class = 255; 351 component_extents = base_extents; 352 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) { 353 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction)) 354 horiz_dir = plan->props.direction; 355 else 356 horiz_dir = hb_script_get_horizontal_direction (plan->props.script); 357 } 358 if (horiz_dir == HB_DIRECTION_LTR) 359 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components; 360 else 361 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components; 362 component_extents.width /= num_lig_components; 363 } 364 } 365 366 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]); 367 if (last_combining_class != this_combining_class) 368 { 369 last_combining_class = this_combining_class; 370 cluster_extents = component_extents; 371 } 372 373 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class); 374 375 buffer->pos[i].x_advance = 0; 376 buffer->pos[i].y_advance = 0; 377 buffer->pos[i].x_offset += x_offset; 378 buffer->pos[i].y_offset += y_offset; 379 380 } else { 381 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 382 x_offset -= buffer->pos[i].x_advance; 383 y_offset -= buffer->pos[i].y_advance; 384 } else { 385 x_offset += buffer->pos[i].x_advance; 386 y_offset += buffer->pos[i].y_advance; 387 } 388 } 389 } 390 391 static inline void 392 position_cluster (const hb_ot_shape_plan_t *plan, 393 hb_font_t *font, 394 hb_buffer_t *buffer, 395 unsigned int start, 396 unsigned int end) 397 { 398 if (end - start < 2) 399 return; 400 401 /* Find the base glyph */ 402 hb_glyph_info_t *info = buffer->info; 403 for (unsigned int i = start; i < end; i++) 404 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i]))) 405 { 406 /* Find mark glyphs */ 407 unsigned int j; 408 for (j = i + 1; j < end; j++) 409 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[j]))) 410 break; 411 412 position_around_base (plan, font, buffer, i, j); 413 414 i = j - 1; 415 } 416 } 417 418 void 419 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan, 420 hb_font_t *font, 421 hb_buffer_t *buffer) 422 { 423 _hb_buffer_assert_gsubgpos_vars (buffer); 424 425 unsigned int start = 0; 426 unsigned int count = buffer->len; 427 hb_glyph_info_t *info = buffer->info; 428 for (unsigned int i = 1; i < count; i++) 429 if (likely (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i])))) { 430 position_cluster (plan, font, buffer, start, i); 431 start = i; 432 } 433 position_cluster (plan, font, buffer, start, count); 434 } 435 436 437 /* Performs old-style TrueType kerning. */ 438 void 439 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan, 440 hb_font_t *font, 441 hb_buffer_t *buffer) 442 { 443 if (!plan->has_kern) return; 444 445 OT::hb_apply_context_t c (1, font, buffer); 446 c.set_lookup_mask (plan->kern_mask); 447 c.set_lookup_props (OT::LookupFlag::IgnoreMarks); 448 OT::hb_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input; 449 skippy_iter.init (&c); 450 451 unsigned int count = buffer->len; 452 hb_glyph_info_t *info = buffer->info; 453 hb_glyph_position_t *pos = buffer->pos; 454 for (unsigned int idx = 0; idx < count;) 455 { 456 skippy_iter.reset (idx, 1); 457 if (!skippy_iter.next ()) 458 { 459 idx++; 460 continue; 461 } 462 463 hb_position_t x_kern, y_kern; 464 font->get_glyph_kerning_for_direction (info[idx].codepoint, 465 info[skippy_iter.idx].codepoint, 466 buffer->props.direction, 467 &x_kern, &y_kern); 468 469 if (x_kern) 470 { 471 hb_position_t kern1 = x_kern >> 1; 472 hb_position_t kern2 = x_kern - kern1; 473 pos[idx].x_advance += kern1; 474 pos[skippy_iter.idx].x_advance += kern2; 475 pos[skippy_iter.idx].x_offset += kern2; 476 } 477 478 if (y_kern) 479 { 480 hb_position_t kern1 = y_kern >> 1; 481 hb_position_t kern2 = y_kern - kern1; 482 pos[idx].y_advance += kern1; 483 pos[skippy_iter.idx].y_advance += kern2; 484 pos[skippy_iter.idx].y_offset += kern2; 485 } 486 487 idx = skippy_iter.idx; 488 } 489 } 490 491 492 /* Adjusts width of various spaces. */ 493 void 494 _hb_ot_shape_fallback_spaces (const hb_ot_shape_plan_t *plan, 495 hb_font_t *font, 496 hb_buffer_t *buffer) 497 { 498 if (!HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction)) 499 return; 500 501 hb_glyph_info_t *info = buffer->info; 502 hb_glyph_position_t *pos = buffer->pos; 503 unsigned int count = buffer->len; 504 for (unsigned int i = 0; i < count; i++) 505 if (_hb_glyph_info_is_unicode_space (&info[i]) && !_hb_glyph_info_ligated (&info[i])) 506 { 507 hb_unicode_funcs_t::space_t space_type = _hb_glyph_info_get_unicode_space_fallback_type (&info[i]); 508 hb_codepoint_t glyph; 509 typedef hb_unicode_funcs_t t; 510 switch (space_type) 511 { 512 case t::NOT_SPACE: /* Shouldn't happen. */ 513 case t::SPACE: 514 break; 515 516 case t::SPACE_EM: 517 case t::SPACE_EM_2: 518 case t::SPACE_EM_3: 519 case t::SPACE_EM_4: 520 case t::SPACE_EM_5: 521 case t::SPACE_EM_6: 522 case t::SPACE_EM_16: 523 pos[i].x_advance = (font->x_scale + ((int) space_type)/2) / (int) space_type; 524 break; 525 526 case t::SPACE_4_EM_18: 527 pos[i].x_advance = font->x_scale * 4 / 18; 528 break; 529 530 case t::SPACE_FIGURE: 531 for (char u = '0'; u <= '9'; u++) 532 if (font->get_nominal_glyph (u, &glyph)) 533 { 534 pos[i].x_advance = font->get_glyph_h_advance (glyph); 535 break; 536 } 537 break; 538 539 case t::SPACE_PUNCTUATION: 540 if (font->get_nominal_glyph ('.', &glyph)) 541 pos[i].x_advance = font->get_glyph_h_advance (glyph); 542 else if (font->get_nominal_glyph (',', &glyph)) 543 pos[i].x_advance = font->get_glyph_h_advance (glyph); 544 break; 545 546 case t::SPACE_NARROW: 547 /* Half-space? 548 * Unicode doc http://www.unicode.org/charts/PDF/U2000.pdf says ~1/4 or 1/5 of EM. 549 * However, in my testing, many fonts have their regular space being about that 550 * size. To me, a percentage of the space width makes more sense. Half is as 551 * good as any. */ 552 pos[i].x_advance /= 2; 553 break; 554 } 555 } 556 } 557
