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) == 0x0E00) 39 { 40 if (unlikely (klass == 0)) 41 { 42 switch (u) 43 { 44 case 0x0E31: 45 case 0x0E34: 46 case 0x0E35: 47 case 0x0E36: 48 case 0x0E37: 49 case 0x0E47: 50 case 0x0E4C: 51 case 0x0E4D: 52 case 0x0E4E: 53 klass = HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT; 54 break; 55 56 case 0x0EB1: 57 case 0x0EB4: 58 case 0x0EB5: 59 case 0x0EB6: 60 case 0x0EB7: 61 case 0x0EBB: 62 case 0x0ECC: 63 case 0x0ECD: 64 klass = HB_UNICODE_COMBINING_CLASS_ABOVE; 65 break; 66 67 case 0x0EBC: 68 klass = HB_UNICODE_COMBINING_CLASS_BELOW; 69 break; 70 } 71 } else { 72 /* Thai virama is below-right */ 73 if (u == 0x0E3A) 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 for (unsigned int i = 0; i < count; i++) 171 if (_hb_glyph_info_get_general_category (&buffer->info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) { 172 unsigned int combining_class = _hb_glyph_info_get_modified_combining_class (&buffer->info[i]); 173 combining_class = recategorize_combining_class (buffer->info[i].codepoint, combining_class); 174 _hb_glyph_info_set_modified_combining_class (&buffer->info[i], combining_class); 175 } 176 } 177 178 179 static void 180 zero_mark_advances (hb_buffer_t *buffer, 181 unsigned int start, 182 unsigned int end) 183 { 184 for (unsigned int i = start; i < end; i++) 185 if (_hb_glyph_info_get_general_category (&buffer->info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) 186 { 187 buffer->pos[i].x_advance = 0; 188 buffer->pos[i].y_advance = 0; 189 } 190 } 191 192 static inline void 193 position_mark (const hb_ot_shape_plan_t *plan, 194 hb_font_t *font, 195 hb_buffer_t *buffer, 196 hb_glyph_extents_t &base_extents, 197 unsigned int i, 198 unsigned int combining_class) 199 { 200 hb_glyph_extents_t mark_extents; 201 if (!font->get_glyph_extents (buffer->info[i].codepoint, 202 &mark_extents)) 203 return; 204 205 hb_position_t y_gap = font->y_scale / 16; 206 207 hb_glyph_position_t &pos = buffer->pos[i]; 208 pos.x_offset = pos.y_offset = 0; 209 210 211 /* We dont position LEFT and RIGHT marks. */ 212 213 /* X positioning */ 214 switch (combining_class) 215 { 216 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW: 217 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE: 218 if (buffer->props.direction == HB_DIRECTION_LTR) { 219 pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing; 220 break; 221 } else if (buffer->props.direction == HB_DIRECTION_RTL) { 222 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing; 223 break; 224 } 225 /* Fall through */ 226 227 default: 228 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW: 229 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE: 230 case HB_UNICODE_COMBINING_CLASS_BELOW: 231 case HB_UNICODE_COMBINING_CLASS_ABOVE: 232 /* Center align. */ 233 pos.x_offset += base_extents.x_bearing + (base_extents.width - mark_extents.width) / 2 - mark_extents.x_bearing; 234 break; 235 236 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT: 237 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT: 238 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT: 239 /* Left align. */ 240 pos.x_offset += base_extents.x_bearing - mark_extents.x_bearing; 241 break; 242 243 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT: 244 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT: 245 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT: 246 /* Right align. */ 247 pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width - mark_extents.x_bearing; 248 break; 249 } 250 251 /* Y positioning */ 252 switch (combining_class) 253 { 254 case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW: 255 case HB_UNICODE_COMBINING_CLASS_BELOW_LEFT: 256 case HB_UNICODE_COMBINING_CLASS_BELOW: 257 case HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT: 258 /* Add gap, fall-through. */ 259 base_extents.height -= y_gap; 260 261 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT: 262 case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW: 263 pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing; 264 /* Never shift up "below" marks. */ 265 if ((y_gap > 0) == (pos.y_offset > 0)) 266 { 267 base_extents.height -= pos.y_offset; 268 pos.y_offset = 0; 269 } 270 base_extents.height += mark_extents.height; 271 break; 272 273 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE: 274 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT: 275 case HB_UNICODE_COMBINING_CLASS_ABOVE: 276 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT: 277 /* Add gap, fall-through. */ 278 base_extents.y_bearing += y_gap; 279 base_extents.height -= y_gap; 280 281 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE: 282 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT: 283 pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height); 284 /* Don't shift down "above" marks too much. */ 285 if ((y_gap > 0) != (pos.y_offset > 0)) 286 { 287 unsigned int correction = -pos.y_offset / 2; 288 base_extents.y_bearing += correction; 289 base_extents.height -= correction; 290 pos.y_offset += correction; 291 } 292 base_extents.y_bearing -= mark_extents.height; 293 base_extents.height += mark_extents.height; 294 break; 295 } 296 } 297 298 static inline void 299 position_around_base (const hb_ot_shape_plan_t *plan, 300 hb_font_t *font, 301 hb_buffer_t *buffer, 302 unsigned int base, 303 unsigned int end) 304 { 305 hb_direction_t horiz_dir = HB_DIRECTION_INVALID; 306 hb_glyph_extents_t base_extents; 307 if (!font->get_glyph_extents (buffer->info[base].codepoint, 308 &base_extents)) 309 { 310 /* If extents don't work, zero marks and go home. */ 311 zero_mark_advances (buffer, base + 1, end); 312 return; 313 } 314 base_extents.x_bearing += buffer->pos[base].x_offset; 315 base_extents.y_bearing += buffer->pos[base].y_offset; 316 317 unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]); 318 unsigned int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]); 319 320 hb_position_t x_offset = 0, y_offset = 0; 321 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 322 x_offset -= buffer->pos[base].x_advance; 323 y_offset -= buffer->pos[base].y_advance; 324 } 325 326 hb_glyph_extents_t component_extents = base_extents; 327 unsigned int last_lig_component = (unsigned int) -1; 328 unsigned int last_combining_class = 255; 329 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */ 330 for (unsigned int i = base + 1; i < end; i++) 331 if (_hb_glyph_info_get_modified_combining_class (&buffer->info[i])) 332 { 333 if (num_lig_components > 1) { 334 unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&buffer->info[i]); 335 unsigned int this_lig_component = _hb_glyph_info_get_lig_comp (&buffer->info[i]) - 1; 336 /* Conditions for attaching to the last component. */ 337 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components) 338 this_lig_component = num_lig_components - 1; 339 if (last_lig_component != this_lig_component) 340 { 341 last_lig_component = this_lig_component; 342 last_combining_class = 255; 343 component_extents = base_extents; 344 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) { 345 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction)) 346 horiz_dir = plan->props.direction; 347 else 348 horiz_dir = hb_script_get_horizontal_direction (plan->props.script); 349 } 350 if (horiz_dir == HB_DIRECTION_LTR) 351 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components; 352 else 353 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components; 354 component_extents.width /= num_lig_components; 355 } 356 } 357 358 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&buffer->info[i]); 359 if (last_combining_class != this_combining_class) 360 { 361 last_combining_class = this_combining_class; 362 cluster_extents = component_extents; 363 } 364 365 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class); 366 367 buffer->pos[i].x_advance = 0; 368 buffer->pos[i].y_advance = 0; 369 buffer->pos[i].x_offset += x_offset; 370 buffer->pos[i].y_offset += y_offset; 371 372 } else { 373 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 374 x_offset -= buffer->pos[i].x_advance; 375 y_offset -= buffer->pos[i].y_advance; 376 } else { 377 x_offset += buffer->pos[i].x_advance; 378 y_offset += buffer->pos[i].y_advance; 379 } 380 } 381 } 382 383 static inline void 384 position_cluster (const hb_ot_shape_plan_t *plan, 385 hb_font_t *font, 386 hb_buffer_t *buffer, 387 unsigned int start, 388 unsigned int end) 389 { 390 if (end - start < 2) 391 return; 392 393 /* Find the base glyph */ 394 for (unsigned int i = start; i < end; i++) 395 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->info[i]))) 396 { 397 /* Find mark glyphs */ 398 unsigned int j; 399 for (j = i + 1; j < end; j++) 400 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->info[j]))) 401 break; 402 403 position_around_base (plan, font, buffer, i, j); 404 405 i = j - 1; 406 } 407 } 408 409 void 410 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan, 411 hb_font_t *font, 412 hb_buffer_t *buffer) 413 { 414 unsigned int start = 0; 415 unsigned int last_cluster = buffer->info[0].cluster; 416 unsigned int count = buffer->len; 417 for (unsigned int i = 1; i < count; i++) 418 if (buffer->info[i].cluster != last_cluster) { 419 position_cluster (plan, font, buffer, start, i); 420 start = i; 421 last_cluster = buffer->info[i].cluster; 422 } 423 position_cluster (plan, font, buffer, start, count); 424 } 425 426 427 /* Performs old-style TrueType kerning. */ 428 void 429 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan, 430 hb_font_t *font, 431 hb_buffer_t *buffer) 432 { 433 if (!plan->has_kern) return; 434 435 unsigned int count = buffer->len; 436 437 OT::hb_apply_context_t c (1, font, buffer); 438 c.set_lookup_mask (plan->kern_mask); 439 c.set_lookup_props (OT::LookupFlag::IgnoreMarks); 440 441 hb_glyph_info_t *info = buffer->info; 442 hb_glyph_position_t *pos = buffer->pos; 443 444 for (unsigned int idx = 0; idx < count;) 445 { 446 OT::hb_apply_context_t::skipping_forward_iterator_t skippy_iter (&c, idx, 1); 447 if (!skippy_iter.next ()) 448 { 449 idx++; 450 continue; 451 } 452 453 hb_position_t x_kern, y_kern; 454 font->get_glyph_kerning_for_direction (info[idx].codepoint, 455 info[skippy_iter.idx].codepoint, 456 buffer->props.direction, 457 &x_kern, &y_kern); 458 459 if (x_kern) 460 { 461 hb_position_t kern1 = x_kern >> 1; 462 hb_position_t kern2 = x_kern - kern1; 463 pos[idx].x_advance += kern1; 464 pos[skippy_iter.idx].x_advance += kern2; 465 pos[skippy_iter.idx].x_offset += kern2; 466 } 467 468 if (y_kern) 469 { 470 hb_position_t kern1 = y_kern >> 1; 471 hb_position_t kern2 = y_kern - kern1; 472 pos[idx].y_advance += kern1; 473 pos[skippy_iter.idx].y_advance += kern2; 474 pos[skippy_iter.idx].y_offset += kern2; 475 } 476 477 idx = skippy_iter.idx; 478 } 479 } 480
