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 base_extents.height += mark_extents.height; 265 break; 266 267 case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE: 268 case HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT: 269 case HB_UNICODE_COMBINING_CLASS_ABOVE: 270 case HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT: 271 /* Add gap, fall-through. */ 272 base_extents.y_bearing += y_gap; 273 base_extents.height -= y_gap; 274 275 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE: 276 case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT: 277 pos.y_offset += base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height); 278 base_extents.y_bearing -= mark_extents.height; 279 base_extents.height += mark_extents.height; 280 break; 281 } 282 } 283 284 static inline void 285 position_around_base (const hb_ot_shape_plan_t *plan, 286 hb_font_t *font, 287 hb_buffer_t *buffer, 288 unsigned int base, 289 unsigned int end) 290 { 291 hb_direction_t horiz_dir = HB_DIRECTION_INVALID; 292 hb_glyph_extents_t base_extents; 293 if (!font->get_glyph_extents (buffer->info[base].codepoint, 294 &base_extents)) 295 { 296 /* If extents don't work, zero marks and go home. */ 297 zero_mark_advances (buffer, base + 1, end); 298 return; 299 } 300 base_extents.x_bearing += buffer->pos[base].x_offset; 301 base_extents.y_bearing += buffer->pos[base].y_offset; 302 303 unsigned int lig_id = get_lig_id (buffer->info[base]); 304 unsigned int num_lig_components = get_lig_num_comps (buffer->info[base]); 305 306 hb_position_t x_offset = 0, y_offset = 0; 307 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 308 x_offset -= buffer->pos[base].x_advance; 309 y_offset -= buffer->pos[base].y_advance; 310 } 311 312 hb_glyph_extents_t component_extents = base_extents; 313 unsigned int last_lig_component = (unsigned int) -1; 314 unsigned int last_combining_class = 255; 315 hb_glyph_extents_t cluster_extents = base_extents; /* Initialization is just to shut gcc up. */ 316 for (unsigned int i = base + 1; i < end; i++) 317 if (_hb_glyph_info_get_modified_combining_class (&buffer->info[i])) 318 { 319 if (num_lig_components > 1) { 320 unsigned int this_lig_id = get_lig_id (buffer->info[i]); 321 unsigned int this_lig_component = get_lig_comp (buffer->info[i]) - 1; 322 /* Conditions for attaching to the last component. */ 323 if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components) 324 this_lig_component = num_lig_components - 1; 325 if (last_lig_component != this_lig_component) 326 { 327 last_lig_component = this_lig_component; 328 last_combining_class = 255; 329 component_extents = base_extents; 330 if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) { 331 if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction)) 332 horiz_dir = plan->props.direction; 333 else 334 horiz_dir = hb_script_get_horizontal_direction (plan->props.script); 335 } 336 if (horiz_dir == HB_DIRECTION_LTR) 337 component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components; 338 else 339 component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components; 340 component_extents.width /= num_lig_components; 341 } 342 } 343 344 unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&buffer->info[i]); 345 if (last_combining_class != this_combining_class) 346 { 347 last_combining_class = this_combining_class; 348 cluster_extents = component_extents; 349 } 350 351 position_mark (plan, font, buffer, cluster_extents, i, this_combining_class); 352 353 buffer->pos[i].x_advance = 0; 354 buffer->pos[i].y_advance = 0; 355 buffer->pos[i].x_offset += x_offset; 356 buffer->pos[i].y_offset += y_offset; 357 358 } else { 359 if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { 360 x_offset -= buffer->pos[i].x_advance; 361 y_offset -= buffer->pos[i].y_advance; 362 } else { 363 x_offset += buffer->pos[i].x_advance; 364 y_offset += buffer->pos[i].y_advance; 365 } 366 } 367 } 368 369 static inline void 370 position_cluster (const hb_ot_shape_plan_t *plan, 371 hb_font_t *font, 372 hb_buffer_t *buffer, 373 unsigned int start, 374 unsigned int end) 375 { 376 if (end - start < 2) 377 return; 378 379 /* Find the base glyph */ 380 for (unsigned int i = start; i < end; i++) 381 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->info[i]))) 382 { 383 /* Find mark glyphs */ 384 unsigned int j; 385 for (j = i + 1; j < end; j++) 386 if (!HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->info[j]))) 387 break; 388 389 position_around_base (plan, font, buffer, i, j); 390 391 i = j - 1; 392 } 393 } 394 395 void 396 _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan, 397 hb_font_t *font, 398 hb_buffer_t *buffer) 399 { 400 unsigned int start = 0; 401 unsigned int last_cluster = buffer->info[0].cluster; 402 unsigned int count = buffer->len; 403 for (unsigned int i = 1; i < count; i++) 404 if (buffer->info[i].cluster != last_cluster) { 405 position_cluster (plan, font, buffer, start, i); 406 start = i; 407 last_cluster = buffer->info[i].cluster; 408 } 409 position_cluster (plan, font, buffer, start, count); 410 } 411 412 413 /* Performs old-style TrueType kerning. */ 414 void 415 _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan, 416 hb_font_t *font, 417 hb_buffer_t *buffer) 418 { 419 unsigned int count = buffer->len; 420 hb_mask_t kern_mask = plan->map.get_1_mask (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction) ? 421 HB_TAG ('k','e','r','n') : HB_TAG ('v','k','r','n')); 422 423 OT::hb_apply_context_t c (1, font, buffer, kern_mask, true/*auto_zwj*/); 424 c.set_lookup_props (OT::LookupFlag::IgnoreMarks); 425 426 for (buffer->idx = 0; buffer->idx < count;) 427 { 428 OT::hb_apply_context_t::skipping_forward_iterator_t skippy_iter (&c, buffer->idx, 1); 429 if (!skippy_iter.next ()) 430 { 431 buffer->idx++; 432 continue; 433 } 434 435 hb_position_t x_kern, y_kern, kern1, kern2; 436 font->get_glyph_kerning_for_direction (buffer->info[buffer->idx].codepoint, 437 buffer->info[skippy_iter.idx].codepoint, 438 buffer->props.direction, 439 &x_kern, &y_kern); 440 441 kern1 = x_kern >> 1; 442 kern2 = x_kern - kern1; 443 buffer->pos[buffer->idx].x_advance += kern1; 444 buffer->pos[skippy_iter.idx].x_advance += kern2; 445 buffer->pos[skippy_iter.idx].x_offset += kern2; 446 447 kern1 = y_kern >> 1; 448 kern2 = y_kern - kern1; 449 buffer->pos[buffer->idx].y_advance += kern1; 450 buffer->pos[skippy_iter.idx].y_advance += kern2; 451 buffer->pos[skippy_iter.idx].y_offset += kern2; 452 453 buffer->idx = skippy_iter.idx; 454 } 455 } 456
