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 dont 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 - 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 + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing; 225 break; 226 } 227 /* Fall through */ 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; 262 263 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT: 264 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW: 265 pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing; 266 /* Never shift up "below" marks. */ 267 if ((y_gap > 0) == (pos.y_offset > 0)) 268 { 269 base_extents.height -= pos.y_offset; 270 pos.y_offset = 0; 271 } 272 base_extents.height += mark_extents.height; 273 break; 274 275 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE: 276 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT: 277 case HB_UNICODE_COMBINING_CLASS_ABOVE: 278 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT: 279 /* Add gap, fall-through. */ 280 base_extents.y_bearing += y_gap; 281 base_extents.height -= y_gap; 282 283 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE: 284 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT: 285 pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height); 286 /* Don't shift down "above" marks too much. */ 287 if ((y_gap > 0) != (pos.y_offset > 0)) 288 { 289 unsigned int correction = -pos.y_offset / 2; 290 base_extents.y_bearing += correction; 291 base_extents.height -= correction; 292 pos.y_offset += correction; 293 } 294 base_extents.y_bearing -= mark_extents.height; 295 base_extents.height += mark_extents.height; 296 break; 297 } 298 } 299 300 static inline void 301 position_around_base (const hb_ot_shape_plan_t *plan, 302 hb_font_t *font, 303 hb_buffer_t *buffer, 304 unsigned int base, 305 unsigned int end) 306 { 307 hb_direction_t horiz_dir = HB_DIRECTION_INVALID; 308 hb_glyph_extents_t base_extents; 309 if (!font->get_glyph_extents (buffer->info[base].codepoint, 310 &base_extents)) 311 { 312 /* If extents don't work, zero marks and go home. */ 313 zero_mark_advances (buffer, base + 1, end); 314 return; 315 } 316 base_extents.x_bearing += buffer->pos[base].x_offset; 317 base_extents.y_bearing += buffer->pos[base].y_offset; 318 319 unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]); 320 unsigned int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]); 321 322 hb_position_t x_offset = 0, y_offset = 0; 323 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 324 x_offset -= buffer->pos[base].x_advance; 325 y_offset -= buffer->pos[base].y_advance; 326 } 327 328 hb_glyph_extents_t component_extents = base_extents; 329 unsigned int last_lig_component = (unsigned int) -1; 330 unsigned int last_combining_class = 255; 331 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */ 332 hb_glyph_info_t *info = buffer->info; 333 for (unsigned int i = base + 1; i < end; i++) 334 if (_hb_glyph_info_get_modified_combining_class (&info[i])) 335 { 336 if (num_lig_components > 1) { 337 unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&info[i]); 338 unsigned int this_lig_component = _hb_glyph_info_get_lig_comp (&info[i]) - 1; 339 /* Conditions for attaching to the last component. */ 340 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components) 341 this_lig_component = num_lig_components - 1; 342 if (last_lig_component != this_lig_component) 343 { 344 last_lig_component = this_lig_component; 345 last_combining_class = 255; 346 component_extents = base_extents; 347 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) { 348 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction)) 349 horiz_dir = plan->props.direction; 350 else 351 horiz_dir = hb_script_get_horizontal_direction (plan->props.script); 352 } 353 if (horiz_dir == HB_DIRECTION_LTR) 354 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components; 355 else 356 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components; 357 component_extents.width /= num_lig_components; 358 } 359 } 360 361 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&info[i]); 362 if (last_combining_class != this_combining_class) 363 { 364 last_combining_class = this_combining_class; 365 cluster_extents = component_extents; 366 } 367 368 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class); 369 370 buffer->pos[i].x_advance = 0; 371 buffer->pos[i].y_advance = 0; 372 buffer->pos[i].x_offset += x_offset; 373 buffer->pos[i].y_offset += y_offset; 374 375 } else { 376 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 377 x_offset -= buffer->pos[i].x_advance; 378 y_offset -= buffer->pos[i].y_advance; 379 } else { 380 x_offset += buffer->pos[i].x_advance; 381 y_offset += buffer->pos[i].y_advance; 382 } 383 } 384 } 385 386 static inline void 387 position_cluster (const hb_ot_shape_plan_t *plan, 388 hb_font_t *font, 389 hb_buffer_t *buffer, 390 unsigned int start, 391 unsigned int end) 392 { 393 if (end - start < 2) 394 return; 395 396 /* Find the base glyph */ 397 hb_glyph_info_t *info = buffer->info; 398 for (unsigned int i = start; i < end; i++) 399 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[i]))) 400 { 401 /* Find mark glyphs */ 402 unsigned int j; 403 for (j = i + 1; j < end; j++) 404 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&info[j]))) 405 break; 406 407 position_around_base (plan, font, buffer, i, j); 408 409 i = j - 1; 410 } 411 } 412 413 void 414 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan, 415 hb_font_t *font, 416 hb_buffer_t *buffer) 417 { 418 unsigned int start = 0; 419 unsigned int last_cluster = buffer->info[0].cluster; 420 unsigned int count = buffer->len; 421 for (unsigned int i = 1; i < count; i++) 422 if (buffer->info[i].cluster != last_cluster) { 423 position_cluster (plan, font, buffer, start, i); 424 start = i; 425 last_cluster = buffer->info[i].cluster; 426 } 427 position_cluster (plan, font, buffer, start, count); 428 } 429 430 431 /* Performs old-style TrueType kerning. */ 432 void 433 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan, 434 hb_font_t *font, 435 hb_buffer_t *buffer) 436 { 437 if (!plan->has_kern) return; 438 439 OT::hb_apply_context_t c (1, font, buffer); 440 c.set_lookup_mask (plan->kern_mask); 441 c.set_lookup_props (OT::LookupFlag::IgnoreMarks); 442 443 unsigned int count = buffer->len; 444 hb_glyph_info_t *info = buffer->info; 445 hb_glyph_position_t *pos = buffer->pos; 446 for (unsigned int idx = 0; idx < count;) 447 { 448 OT::hb_apply_context_t::skipping_forward_iterator_t skippy_iter (&c, idx, 1); 449 if (!skippy_iter.next ()) 450 { 451 idx++; 452 continue; 453 } 454 455 hb_position_t x_kern, y_kern; 456 font->get_glyph_kerning_for_direction (info[idx].codepoint, 457 info[skippy_iter.idx].codepoint, 458 buffer->props.direction, 459 &x_kern, &y_kern); 460 461 if (x_kern) 462 { 463 hb_position_t kern1 = x_kern >> 1; 464 hb_position_t kern2 = x_kern - kern1; 465 pos[idx].x_advance += kern1; 466 pos[skippy_iter.idx].x_advance += kern2; 467 pos[skippy_iter.idx].x_offset += kern2; 468 } 469 470 if (y_kern) 471 { 472 hb_position_t kern1 = y_kern >> 1; 473 hb_position_t kern2 = y_kern - kern1; 474 pos[idx].y_advance += kern1; 475 pos[skippy_iter.idx].y_advance += kern2; 476 pos[skippy_iter.idx].y_offset += kern2; 477 } 478 479 idx = skippy_iter.idx; 480 } 481 } 482
