hb-ot-shape.cc revision 0736915b8ed789a209205fec762997af3a8af89c
1/* 2 * Copyright © 2009,2010 Red Hat, Inc. 3 * Copyright © 2010,2011,2012 Google, Inc. 4 * 5 * This is part of HarfBuzz, a text shaping library. 6 * 7 * Permission is hereby granted, without written agreement and without 8 * license or royalty fees, to use, copy, modify, and distribute this 9 * software and its documentation for any purpose, provided that the 10 * above copyright notice and the following two paragraphs appear in 11 * all copies of this software. 12 * 13 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR 14 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 15 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN 16 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 17 * DAMAGE. 18 * 19 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, 20 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 21 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 22 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO 23 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 24 * 25 * Red Hat Author(s): Behdad Esfahbod 26 * Google Author(s): Behdad Esfahbod 27 */ 28 29#define HB_SHAPER ot 30#define hb_ot_shaper_face_data_t hb_ot_layout_t 31#define hb_ot_shaper_shape_plan_data_t hb_ot_shape_plan_t 32#include "hb-shaper-impl-private.hh" 33 34#include "hb-ot-shape-private.hh" 35#include "hb-ot-shape-complex-private.hh" 36#include "hb-ot-shape-fallback-private.hh" 37#include "hb-ot-shape-normalize-private.hh" 38 39#include "hb-ot-layout-private.hh" 40#include "hb-set-private.hh" 41 42 43static hb_tag_t common_features[] = { 44 HB_TAG('c','c','m','p'), 45 HB_TAG('l','i','g','a'), 46 HB_TAG('l','o','c','l'), 47 HB_TAG('m','a','r','k'), 48 HB_TAG('m','k','m','k'), 49 HB_TAG('r','l','i','g'), 50}; 51 52 53static hb_tag_t horizontal_features[] = { 54 HB_TAG('c','a','l','t'), 55 HB_TAG('c','l','i','g'), 56 HB_TAG('c','u','r','s'), 57 HB_TAG('k','e','r','n'), 58 HB_TAG('r','c','l','t'), 59}; 60 61/* Note: 62 * Technically speaking, vrt2 and vert are mutually exclusive. 63 * According to the spec, valt and vpal are also mutually exclusive. 64 * But we apply them all for now. 65 */ 66static hb_tag_t vertical_features[] = { 67 HB_TAG('v','a','l','t'), 68 HB_TAG('v','e','r','t'), 69 HB_TAG('v','k','r','n'), 70 HB_TAG('v','p','a','l'), 71 HB_TAG('v','r','t','2'), 72}; 73 74 75 76static void 77hb_ot_shape_collect_features (hb_ot_shape_planner_t *planner, 78 const hb_segment_properties_t *props, 79 const hb_feature_t *user_features, 80 unsigned int num_user_features) 81{ 82 hb_ot_map_builder_t *map = &planner->map; 83 84 switch (props->direction) { 85 case HB_DIRECTION_LTR: 86 map->add_bool_feature (HB_TAG ('l','t','r','a')); 87 map->add_bool_feature (HB_TAG ('l','t','r','m')); 88 break; 89 case HB_DIRECTION_RTL: 90 map->add_bool_feature (HB_TAG ('r','t','l','a')); 91 map->add_bool_feature (HB_TAG ('r','t','l','m'), false); 92 break; 93 case HB_DIRECTION_TTB: 94 case HB_DIRECTION_BTT: 95 case HB_DIRECTION_INVALID: 96 default: 97 break; 98 } 99 100#define ADD_FEATURES(array) \ 101 HB_STMT_START { \ 102 for (unsigned int i = 0; i < ARRAY_LENGTH (array); i++) \ 103 map->add_bool_feature (array[i]); \ 104 } HB_STMT_END 105 106 if (planner->shaper->collect_features) 107 planner->shaper->collect_features (planner); 108 109 ADD_FEATURES (common_features); 110 111 if (HB_DIRECTION_IS_HORIZONTAL (props->direction)) 112 ADD_FEATURES (horizontal_features); 113 else 114 ADD_FEATURES (vertical_features); 115 116 if (planner->shaper->override_features) 117 planner->shaper->override_features (planner); 118 119#undef ADD_FEATURES 120 121 for (unsigned int i = 0; i < num_user_features; i++) { 122 const hb_feature_t *feature = &user_features[i]; 123 map->add_feature (feature->tag, feature->value, (feature->start == 0 && feature->end == (unsigned int) -1)); 124 } 125} 126 127 128/* 129 * shaper face data 130 */ 131 132hb_ot_shaper_face_data_t * 133_hb_ot_shaper_face_data_create (hb_face_t *face) 134{ 135 return _hb_ot_layout_create (face); 136} 137 138void 139_hb_ot_shaper_face_data_destroy (hb_ot_shaper_face_data_t *data) 140{ 141 _hb_ot_layout_destroy (data); 142} 143 144 145/* 146 * shaper font data 147 */ 148 149struct hb_ot_shaper_font_data_t {}; 150 151hb_ot_shaper_font_data_t * 152_hb_ot_shaper_font_data_create (hb_font_t *font) 153{ 154 return (hb_ot_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED; 155} 156 157void 158_hb_ot_shaper_font_data_destroy (hb_ot_shaper_font_data_t *data) 159{ 160} 161 162 163/* 164 * shaper shape_plan data 165 */ 166 167hb_ot_shaper_shape_plan_data_t * 168_hb_ot_shaper_shape_plan_data_create (hb_shape_plan_t *shape_plan, 169 const hb_feature_t *user_features, 170 unsigned int num_user_features) 171{ 172 hb_ot_shape_plan_t *plan = (hb_ot_shape_plan_t *) calloc (1, sizeof (hb_ot_shape_plan_t)); 173 if (unlikely (!plan)) 174 return NULL; 175 176 hb_ot_shape_planner_t planner (shape_plan); 177 178 planner.shaper = hb_ot_shape_complex_categorize (&planner); 179 180 hb_ot_shape_collect_features (&planner, &shape_plan->props, user_features, num_user_features); 181 182 planner.compile (*plan); 183 184 if (plan->shaper->data_create) { 185 plan->data = plan->shaper->data_create (plan); 186 if (unlikely (!plan->data)) 187 return NULL; 188 } 189 190 return plan; 191} 192 193void 194_hb_ot_shaper_shape_plan_data_destroy (hb_ot_shaper_shape_plan_data_t *plan) 195{ 196 if (plan->shaper->data_destroy) 197 plan->shaper->data_destroy (const_cast<void *> (plan->data)); 198 199 plan->finish (); 200 201 free (plan); 202} 203 204 205/* 206 * shaper 207 */ 208 209struct hb_ot_shape_context_t 210{ 211 hb_ot_shape_plan_t *plan; 212 hb_font_t *font; 213 hb_face_t *face; 214 hb_buffer_t *buffer; 215 const hb_feature_t *user_features; 216 unsigned int num_user_features; 217 218 /* Transient stuff */ 219 hb_direction_t target_direction; 220}; 221 222 223 224/* Main shaper */ 225 226 227/* Prepare */ 228 229static void 230hb_set_unicode_props (hb_buffer_t *buffer) 231{ 232 unsigned int count = buffer->len; 233 for (unsigned int i = 0; i < count; i++) 234 _hb_glyph_info_set_unicode_props (&buffer->info[i], buffer->unicode); 235} 236 237static void 238hb_insert_dotted_circle (hb_buffer_t *buffer, hb_font_t *font) 239{ 240 if (buffer->context_len[0] || 241 _hb_glyph_info_get_general_category (&buffer->info[0]) != 242 HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) 243 return; 244 245 hb_codepoint_t dottedcircle_glyph; 246 if (!font->get_glyph (0x25CC, 0, &dottedcircle_glyph)) 247 return; 248 249 hb_glyph_info_t dottedcircle; 250 dottedcircle.codepoint = 0x25CC; 251 _hb_glyph_info_set_unicode_props (&dottedcircle, buffer->unicode); 252 253 buffer->clear_output (); 254 255 buffer->idx = 0; 256 hb_glyph_info_t info = dottedcircle; 257 info.cluster = buffer->cur().cluster; 258 info.mask = buffer->cur().mask; 259 buffer->output_info (info); 260 while (buffer->idx < buffer->len) 261 buffer->next_glyph (); 262 263 buffer->swap_buffers (); 264} 265 266static void 267hb_form_clusters (hb_buffer_t *buffer) 268{ 269 unsigned int count = buffer->len; 270 for (unsigned int i = 1; i < count; i++) 271 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->info[i]))) 272 buffer->merge_clusters (i - 1, i + 1); 273} 274 275static void 276hb_ensure_native_direction (hb_buffer_t *buffer) 277{ 278 hb_direction_t direction = buffer->props.direction; 279 280 /* TODO vertical: 281 * The only BTT vertical script is Ogham, but it's not clear to me whether OpenType 282 * Ogham fonts are supposed to be implemented BTT or not. Need to research that 283 * first. */ 284 if ((HB_DIRECTION_IS_HORIZONTAL (direction) && direction != hb_script_get_horizontal_direction (buffer->props.script)) || 285 (HB_DIRECTION_IS_VERTICAL (direction) && direction != HB_DIRECTION_TTB)) 286 { 287 hb_buffer_reverse_clusters (buffer); 288 buffer->props.direction = HB_DIRECTION_REVERSE (buffer->props.direction); 289 } 290} 291 292 293/* Substitute */ 294 295static inline void 296hb_ot_mirror_chars (hb_ot_shape_context_t *c) 297{ 298 if (HB_DIRECTION_IS_FORWARD (c->target_direction)) 299 return; 300 301 hb_unicode_funcs_t *unicode = c->buffer->unicode; 302 hb_mask_t rtlm_mask = c->plan->map.get_1_mask (HB_TAG ('r','t','l','m')); 303 304 unsigned int count = c->buffer->len; 305 for (unsigned int i = 0; i < count; i++) { 306 hb_codepoint_t codepoint = unicode->mirroring (c->buffer->info[i].codepoint); 307 if (likely (codepoint == c->buffer->info[i].codepoint)) 308 c->buffer->info[i].mask |= rtlm_mask; 309 else 310 c->buffer->info[i].codepoint = codepoint; 311 } 312} 313 314static inline void 315hb_ot_shape_setup_masks (hb_ot_shape_context_t *c) 316{ 317 hb_ot_map_t *map = &c->plan->map; 318 319 hb_mask_t global_mask = map->get_global_mask (); 320 c->buffer->reset_masks (global_mask); 321 322 if (c->plan->shaper->setup_masks) 323 c->plan->shaper->setup_masks (c->plan, c->buffer, c->font); 324 325 for (unsigned int i = 0; i < c->num_user_features; i++) 326 { 327 const hb_feature_t *feature = &c->user_features[i]; 328 if (!(feature->start == 0 && feature->end == (unsigned int)-1)) { 329 unsigned int shift; 330 hb_mask_t mask = map->get_mask (feature->tag, &shift); 331 c->buffer->set_masks (feature->value << shift, mask, feature->start, feature->end); 332 } 333 } 334} 335 336static inline void 337hb_ot_map_glyphs_fast (hb_buffer_t *buffer) 338{ 339 /* Normalization process sets up glyph_index(), we just copy it. */ 340 unsigned int count = buffer->len; 341 for (unsigned int i = 0; i < count; i++) 342 buffer->info[i].codepoint = buffer->info[i].glyph_index(); 343} 344 345static inline void 346hb_synthesize_glyph_classes (hb_ot_shape_context_t *c) 347{ 348 unsigned int count = c->buffer->len; 349 for (unsigned int i = 0; i < count; i++) 350 c->buffer->info[i].glyph_props() = _hb_glyph_info_get_general_category (&c->buffer->info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK ? 351 HB_OT_LAYOUT_GLYPH_CLASS_MARK : 352 HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH; 353} 354 355static inline void 356hb_ot_substitute_default (hb_ot_shape_context_t *c) 357{ 358 if (c->plan->shaper->preprocess_text) 359 c->plan->shaper->preprocess_text (c->plan, c->buffer, c->font); 360 361 hb_ot_mirror_chars (c); 362 363 HB_BUFFER_ALLOCATE_VAR (c->buffer, glyph_index); 364 365 _hb_ot_shape_normalize (c->plan->shaper, c->buffer, c->font); 366 367 hb_ot_shape_setup_masks (c); 368 369 /* This is unfortunate to go here, but necessary... */ 370 if (!hb_ot_layout_has_positioning (c->face)) 371 _hb_ot_shape_fallback_position_recategorize_marks (c->plan, c->font, c->buffer); 372 373 hb_ot_map_glyphs_fast (c->buffer); 374 375 HB_BUFFER_DEALLOCATE_VAR (c->buffer, glyph_index); 376} 377 378static inline void 379hb_ot_substitute_complex (hb_ot_shape_context_t *c) 380{ 381 hb_ot_layout_substitute_start (c->font, c->buffer); 382 383 if (!hb_ot_layout_has_glyph_classes (c->face)) 384 hb_synthesize_glyph_classes (c); 385 386 c->plan->substitute (c->font, c->buffer); 387 388 hb_ot_layout_substitute_finish (c->font, c->buffer); 389 390 return; 391} 392 393static inline void 394hb_ot_substitute (hb_ot_shape_context_t *c) 395{ 396 hb_ot_substitute_default (c); 397 hb_ot_substitute_complex (c); 398} 399 400/* Position */ 401 402static inline void 403hb_ot_position_default (hb_ot_shape_context_t *c) 404{ 405 hb_ot_layout_position_start (c->font, c->buffer); 406 407 unsigned int count = c->buffer->len; 408 for (unsigned int i = 0; i < count; i++) { 409 c->font->get_glyph_advance_for_direction (c->buffer->info[i].codepoint, 410 c->buffer->props.direction, 411 &c->buffer->pos[i].x_advance, 412 &c->buffer->pos[i].y_advance); 413 c->font->subtract_glyph_origin_for_direction (c->buffer->info[i].codepoint, 414 c->buffer->props.direction, 415 &c->buffer->pos[i].x_offset, 416 &c->buffer->pos[i].y_offset); 417 } 418} 419 420static inline bool 421hb_ot_position_complex (hb_ot_shape_context_t *c) 422{ 423 bool ret = false; 424 425 if (hb_ot_layout_has_positioning (c->face)) 426 { 427 /* Change glyph origin to what GPOS expects, apply GPOS, change it back. */ 428 429 unsigned int count = c->buffer->len; 430 for (unsigned int i = 0; i < count; i++) { 431 c->font->add_glyph_origin_for_direction (c->buffer->info[i].codepoint, 432 HB_DIRECTION_LTR, 433 &c->buffer->pos[i].x_offset, 434 &c->buffer->pos[i].y_offset); 435 } 436 437 c->plan->position (c->font, c->buffer); 438 439 for (unsigned int i = 0; i < count; i++) { 440 c->font->subtract_glyph_origin_for_direction (c->buffer->info[i].codepoint, 441 HB_DIRECTION_LTR, 442 &c->buffer->pos[i].x_offset, 443 &c->buffer->pos[i].y_offset); 444 } 445 446 ret = true; 447 } 448 449 hb_ot_layout_position_finish (c->font, c->buffer, c->plan->shaper->zero_width_attached_marks); 450 451 return ret; 452} 453 454static inline void 455hb_ot_position_complex_fallback (hb_ot_shape_context_t *c) 456{ 457 _hb_ot_shape_fallback_position (c->plan, c->font, c->buffer); 458} 459 460static inline void 461hb_ot_truetype_kern (hb_ot_shape_context_t *c) 462{ 463 /* TODO Check for kern=0 */ 464 unsigned int count = c->buffer->len; 465 for (unsigned int i = 1; i < count; i++) { 466 hb_position_t x_kern, y_kern, kern1, kern2; 467 c->font->get_glyph_kerning_for_direction (c->buffer->info[i - 1].codepoint, c->buffer->info[i].codepoint, 468 c->buffer->props.direction, 469 &x_kern, &y_kern); 470 471 kern1 = x_kern >> 1; 472 kern2 = x_kern - kern1; 473 c->buffer->pos[i - 1].x_advance += kern1; 474 c->buffer->pos[i].x_advance += kern2; 475 c->buffer->pos[i].x_offset += kern2; 476 477 kern1 = y_kern >> 1; 478 kern2 = y_kern - kern1; 479 c->buffer->pos[i - 1].y_advance += kern1; 480 c->buffer->pos[i].y_advance += kern2; 481 c->buffer->pos[i].y_offset += kern2; 482 } 483} 484 485static inline void 486hb_position_complex_fallback_visual (hb_ot_shape_context_t *c) 487{ 488 hb_ot_truetype_kern (c); 489} 490 491static inline void 492hb_ot_position (hb_ot_shape_context_t *c) 493{ 494 hb_ot_position_default (c); 495 496 hb_bool_t fallback = !hb_ot_position_complex (c); 497 498 if (fallback) 499 hb_ot_position_complex_fallback (c); 500 501 if (HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction)) 502 hb_buffer_reverse (c->buffer); 503 504 if (fallback) 505 hb_position_complex_fallback_visual (c); 506} 507 508 509/* Post-process */ 510 511static void 512hb_ot_hide_zerowidth (hb_ot_shape_context_t *c) 513{ 514 hb_codepoint_t space = 0; 515 516 unsigned int count = c->buffer->len; 517 for (unsigned int i = 0; i < count; i++) 518 if (unlikely (!is_a_ligature (c->buffer->info[i]) && 519 _hb_glyph_info_is_default_ignorable (&c->buffer->info[i]))) 520 { 521 if (!space) { 522 /* We assume that the space glyph is not gid0. */ 523 if (unlikely (!c->font->get_glyph (' ', 0, &space)) || !space) 524 return; /* No point! */ 525 } 526 c->buffer->info[i].codepoint = space; 527 c->buffer->pos[i].x_advance = 0; 528 c->buffer->pos[i].y_advance = 0; 529 } 530} 531 532 533/* Pull it all together! */ 534 535static void 536hb_ot_shape_internal (hb_ot_shape_context_t *c) 537{ 538 c->buffer->deallocate_var_all (); 539 540 /* Save the original direction, we use it later. */ 541 c->target_direction = c->buffer->props.direction; 542 543 HB_BUFFER_ALLOCATE_VAR (c->buffer, unicode_props0); 544 HB_BUFFER_ALLOCATE_VAR (c->buffer, unicode_props1); 545 546 c->buffer->clear_output (); 547 548 hb_set_unicode_props (c->buffer); 549 hb_insert_dotted_circle (c->buffer, c->font); 550 hb_form_clusters (c->buffer); 551 552 hb_ensure_native_direction (c->buffer); 553 554 hb_ot_substitute (c); 555 hb_ot_position (c); 556 557 hb_ot_hide_zerowidth (c); 558 559 HB_BUFFER_DEALLOCATE_VAR (c->buffer, unicode_props1); 560 HB_BUFFER_DEALLOCATE_VAR (c->buffer, unicode_props0); 561 562 c->buffer->props.direction = c->target_direction; 563 564 c->buffer->deallocate_var_all (); 565} 566 567 568hb_bool_t 569_hb_ot_shape (hb_shape_plan_t *shape_plan, 570 hb_font_t *font, 571 hb_buffer_t *buffer, 572 const hb_feature_t *features, 573 unsigned int num_features) 574{ 575 hb_ot_shape_context_t c = {HB_SHAPER_DATA_GET (shape_plan), font, font->face, buffer, features, num_features}; 576 hb_ot_shape_internal (&c); 577 578 return true; 579} 580 581 582 583static inline void 584hb_ot_map_glyphs_dumb (hb_font_t *font, 585 hb_buffer_t *buffer) 586{ 587 unsigned int count = buffer->len; 588 for (unsigned int i = 0; i < count; i++) 589 font->get_glyph (buffer->info[i].codepoint, 0, &buffer->info[i].codepoint); 590} 591 592void 593hb_ot_shape_glyphs_closure (hb_font_t *font, 594 hb_buffer_t *buffer, 595 const hb_feature_t *features, 596 unsigned int num_features, 597 hb_set_t *glyphs) 598{ 599 hb_ot_shape_plan_t plan; 600 601 buffer->guess_properties (); 602 603 /* TODO cache / ensure correct backend, etc. */ 604 hb_shape_plan_t *shape_plan = hb_shape_plan_create (font->face, &buffer->props, features, num_features, NULL); 605 606 /* TODO: normalization? have shapers do closure()? */ 607 /* TODO: Deal with mirrored chars? */ 608 hb_ot_map_glyphs_dumb (font, buffer); 609 610 /* Seed it. It's user's responsibility to have cleard glyphs 611 * if that's what they desire. */ 612 unsigned int count = buffer->len; 613 for (unsigned int i = 0; i < count; i++) 614 glyphs->add (buffer->info[i].codepoint); 615 616 /* And find transitive closure. */ 617 hb_set_t copy; 618 copy.init (); 619 620 do { 621 copy.set (glyphs); 622 HB_SHAPER_DATA_GET (shape_plan)->substitute_closure (font->face, glyphs); 623 } while (!copy.equal (glyphs)); 624 625 hb_shape_plan_destroy (shape_plan); 626} 627