1 /***************************************************************************/ 2 /* */ 3 /* afcjk.c */ 4 /* */ 5 /* Auto-fitter hinting routines for CJK writing system (body). */ 6 /* */ 7 /* Copyright 2006-2014 by */ 8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ 9 /* */ 10 /* This file is part of the FreeType project, and may only be used, */ 11 /* modified, and distributed under the terms of the FreeType project */ 12 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 13 /* this file you indicate that you have read the license and */ 14 /* understand and accept it fully. */ 15 /* */ 16 /***************************************************************************/ 17 18 /* 19 * The algorithm is based on akito's autohint patch, available here: 20 * 21 * http://www.kde.gr.jp/~akito/patch/freetype2/ 22 * 23 */ 24 25 #include <ft2build.h> 26 #include FT_ADVANCES_H 27 #include FT_INTERNAL_DEBUG_H 28 29 #include "afglobal.h" 30 #include "afpic.h" 31 #include "aflatin.h" 32 33 34 #ifdef AF_CONFIG_OPTION_CJK 35 36 #undef AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT 37 38 #include "afcjk.h" 39 #include "aferrors.h" 40 41 42 #ifdef AF_CONFIG_OPTION_USE_WARPER 43 #include "afwarp.h" 44 #endif 45 46 47 /*************************************************************************/ 48 /* */ 49 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ 50 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ 51 /* messages during execution. */ 52 /* */ 53 #undef FT_COMPONENT 54 #define FT_COMPONENT trace_afcjk 55 56 57 /*************************************************************************/ 58 /*************************************************************************/ 59 /***** *****/ 60 /***** C J K G L O B A L M E T R I C S *****/ 61 /***** *****/ 62 /*************************************************************************/ 63 /*************************************************************************/ 64 65 66 /* Basically the Latin version with AF_CJKMetrics */ 67 /* to replace AF_LatinMetrics. */ 68 69 FT_LOCAL_DEF( void ) 70 af_cjk_metrics_init_widths( AF_CJKMetrics metrics, 71 FT_Face face ) 72 { 73 /* scan the array of segments in each direction */ 74 AF_GlyphHintsRec hints[1]; 75 76 77 FT_TRACE5(( "\n" 78 "cjk standard widths computation (style `%s')\n" 79 "===================================================\n" 80 "\n", 81 af_style_names[metrics->root.style_class->style] )); 82 83 af_glyph_hints_init( hints, face->memory ); 84 85 metrics->axis[AF_DIMENSION_HORZ].width_count = 0; 86 metrics->axis[AF_DIMENSION_VERT].width_count = 0; 87 88 { 89 FT_Error error; 90 FT_ULong glyph_index; 91 FT_Long y_offset; 92 int dim; 93 AF_CJKMetricsRec dummy[1]; 94 AF_Scaler scaler = &dummy->root.scaler; 95 96 #ifdef FT_CONFIG_OPTION_PIC 97 AF_FaceGlobals globals = metrics->root.globals; 98 #endif 99 100 AF_StyleClass style_class = metrics->root.style_class; 101 AF_ScriptClass script_class = AF_SCRIPT_CLASSES_GET 102 [style_class->script]; 103 104 FT_UInt32 standard_char; 105 106 107 standard_char = script_class->standard_char1; 108 af_get_char_index( &metrics->root, 109 standard_char, 110 &glyph_index, 111 &y_offset ); 112 if ( !glyph_index ) 113 { 114 if ( script_class->standard_char2 ) 115 { 116 standard_char = script_class->standard_char2; 117 af_get_char_index( &metrics->root, 118 standard_char, 119 &glyph_index, 120 &y_offset ); 121 if ( !glyph_index ) 122 { 123 if ( script_class->standard_char3 ) 124 { 125 standard_char = script_class->standard_char3; 126 af_get_char_index( &metrics->root, 127 standard_char, 128 &glyph_index, 129 &y_offset ); 130 if ( !glyph_index ) 131 goto Exit; 132 } 133 else 134 goto Exit; 135 } 136 } 137 else 138 goto Exit; 139 } 140 141 FT_TRACE5(( "standard character: U+%04lX (glyph index %d)\n", 142 standard_char, glyph_index )); 143 144 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); 145 if ( error || face->glyph->outline.n_points <= 0 ) 146 goto Exit; 147 148 FT_ZERO( dummy ); 149 150 dummy->units_per_em = metrics->units_per_em; 151 152 scaler->x_scale = 0x10000L; 153 scaler->y_scale = 0x10000L; 154 scaler->x_delta = 0; 155 scaler->y_delta = 0; 156 157 scaler->face = face; 158 scaler->render_mode = FT_RENDER_MODE_NORMAL; 159 scaler->flags = 0; 160 161 af_glyph_hints_rescale( hints, (AF_StyleMetrics)dummy ); 162 163 error = af_glyph_hints_reload( hints, &face->glyph->outline ); 164 if ( error ) 165 goto Exit; 166 167 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 168 { 169 AF_CJKAxis axis = &metrics->axis[dim]; 170 AF_AxisHints axhints = &hints->axis[dim]; 171 AF_Segment seg, limit, link; 172 FT_UInt num_widths = 0; 173 174 175 error = af_latin_hints_compute_segments( hints, 176 (AF_Dimension)dim ); 177 if ( error ) 178 goto Exit; 179 180 af_latin_hints_link_segments( hints, 181 0, 182 NULL, 183 (AF_Dimension)dim ); 184 185 seg = axhints->segments; 186 limit = seg + axhints->num_segments; 187 188 for ( ; seg < limit; seg++ ) 189 { 190 link = seg->link; 191 192 /* we only consider stem segments there! */ 193 if ( link && link->link == seg && link > seg ) 194 { 195 FT_Pos dist; 196 197 198 dist = seg->pos - link->pos; 199 if ( dist < 0 ) 200 dist = -dist; 201 202 if ( num_widths < AF_CJK_MAX_WIDTHS ) 203 axis->widths[num_widths++].org = dist; 204 } 205 } 206 207 /* this also replaces multiple almost identical stem widths */ 208 /* with a single one (the value 100 is heuristic) */ 209 af_sort_and_quantize_widths( &num_widths, axis->widths, 210 dummy->units_per_em / 100 ); 211 axis->width_count = num_widths; 212 } 213 214 Exit: 215 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 216 { 217 AF_CJKAxis axis = &metrics->axis[dim]; 218 FT_Pos stdw; 219 220 221 stdw = ( axis->width_count > 0 ) ? axis->widths[0].org 222 : AF_LATIN_CONSTANT( metrics, 50 ); 223 224 /* let's try 20% of the smallest width */ 225 axis->edge_distance_threshold = stdw / 5; 226 axis->standard_width = stdw; 227 axis->extra_light = 0; 228 229 #ifdef FT_DEBUG_LEVEL_TRACE 230 { 231 FT_UInt i; 232 233 234 FT_TRACE5(( "%s widths:\n", 235 dim == AF_DIMENSION_VERT ? "horizontal" 236 : "vertical" )); 237 238 FT_TRACE5(( " %d (standard)", axis->standard_width )); 239 for ( i = 1; i < axis->width_count; i++ ) 240 FT_TRACE5(( " %d", axis->widths[i].org )); 241 242 FT_TRACE5(( "\n" )); 243 } 244 #endif 245 } 246 } 247 248 FT_TRACE5(( "\n" )); 249 250 af_glyph_hints_done( hints ); 251 } 252 253 254 /* Find all blue zones. */ 255 256 static void 257 af_cjk_metrics_init_blues( AF_CJKMetrics metrics, 258 FT_Face face ) 259 { 260 FT_Pos fills[AF_BLUE_STRING_MAX_LEN]; 261 FT_Pos flats[AF_BLUE_STRING_MAX_LEN]; 262 263 FT_Int num_fills; 264 FT_Int num_flats; 265 266 FT_Bool fill; 267 268 AF_CJKBlue blue; 269 FT_Error error; 270 AF_CJKAxis axis; 271 FT_Outline outline; 272 273 AF_StyleClass sc = metrics->root.style_class; 274 275 AF_Blue_Stringset bss = sc->blue_stringset; 276 const AF_Blue_StringRec* bs = &af_blue_stringsets[bss]; 277 278 279 /* we walk over the blue character strings as specified in the */ 280 /* style's entry in the `af_blue_stringset' array, computing its */ 281 /* extremum points (depending on the string properties) */ 282 283 FT_TRACE5(( "cjk blue zones computation\n" 284 "==========================\n" 285 "\n" )); 286 287 for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ ) 288 { 289 const char* p = &af_blue_strings[bs->string]; 290 FT_Pos* blue_ref; 291 FT_Pos* blue_shoot; 292 293 294 if ( AF_CJK_IS_HORIZ_BLUE( bs ) ) 295 axis = &metrics->axis[AF_DIMENSION_HORZ]; 296 else 297 axis = &metrics->axis[AF_DIMENSION_VERT]; 298 299 #ifdef FT_DEBUG_LEVEL_TRACE 300 { 301 FT_String* cjk_blue_name[4] = 302 { 303 (FT_String*)"bottom", /* -- , -- */ 304 (FT_String*)"top", /* -- , TOP */ 305 (FT_String*)"left", /* HORIZ, -- */ 306 (FT_String*)"right" /* HORIZ, TOP */ 307 }; 308 309 310 FT_TRACE5(( "blue zone %d (%s):\n", 311 axis->blue_count, 312 cjk_blue_name[AF_CJK_IS_HORIZ_BLUE( bs ) | 313 AF_CJK_IS_TOP_BLUE( bs ) ] )); 314 } 315 #endif /* FT_DEBUG_LEVEL_TRACE */ 316 317 num_fills = 0; 318 num_flats = 0; 319 320 fill = 1; /* start with characters that define fill values */ 321 FT_TRACE5(( " [overshoot values]\n" )); 322 323 while ( *p ) 324 { 325 FT_ULong ch; 326 FT_ULong glyph_index; 327 FT_Long y_offset; 328 FT_Pos best_pos; /* same as points.y or points.x, resp. */ 329 FT_Int best_point; 330 FT_Vector* points; 331 332 333 GET_UTF8_CHAR( ch, p ); 334 335 /* switch to characters that define flat values */ 336 if ( ch == '|' ) 337 { 338 fill = 0; 339 FT_TRACE5(( " [reference values]\n" )); 340 continue; 341 } 342 343 /* load the character in the face -- skip unknown or empty ones */ 344 af_get_char_index( &metrics->root, ch, &glyph_index, &y_offset ); 345 if ( glyph_index == 0 ) 346 { 347 FT_TRACE5(( " U+%04lX unavailable\n", ch )); 348 continue; 349 } 350 351 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); 352 outline = face->glyph->outline; 353 if ( error || outline.n_points <= 0 ) 354 { 355 FT_TRACE5(( " U+%04lX contains no outlines\n", ch )); 356 continue; 357 } 358 359 /* now compute min or max point indices and coordinates */ 360 points = outline.points; 361 best_point = -1; 362 best_pos = 0; /* make compiler happy */ 363 364 { 365 FT_Int nn; 366 FT_Int first = 0; 367 FT_Int last = -1; 368 369 370 for ( nn = 0; nn < outline.n_contours; first = last + 1, nn++ ) 371 { 372 FT_Int pp; 373 374 375 last = outline.contours[nn]; 376 377 /* Avoid single-point contours since they are never rasterized. */ 378 /* In some fonts, they correspond to mark attachment points */ 379 /* which are way outside of the glyph's real outline. */ 380 if ( last <= first ) 381 continue; 382 383 if ( AF_CJK_IS_HORIZ_BLUE( bs ) ) 384 { 385 if ( AF_CJK_IS_RIGHT_BLUE( bs ) ) 386 { 387 for ( pp = first; pp <= last; pp++ ) 388 if ( best_point < 0 || points[pp].x > best_pos ) 389 { 390 best_point = pp; 391 best_pos = points[pp].x; 392 } 393 } 394 else 395 { 396 for ( pp = first; pp <= last; pp++ ) 397 if ( best_point < 0 || points[pp].x < best_pos ) 398 { 399 best_point = pp; 400 best_pos = points[pp].x; 401 } 402 } 403 } 404 else 405 { 406 if ( AF_CJK_IS_TOP_BLUE( bs ) ) 407 { 408 for ( pp = first; pp <= last; pp++ ) 409 if ( best_point < 0 || points[pp].y > best_pos ) 410 { 411 best_point = pp; 412 best_pos = points[pp].y; 413 } 414 } 415 else 416 { 417 for ( pp = first; pp <= last; pp++ ) 418 if ( best_point < 0 || points[pp].y < best_pos ) 419 { 420 best_point = pp; 421 best_pos = points[pp].y; 422 } 423 } 424 } 425 } 426 427 FT_TRACE5(( " U+%04lX: best_pos = %5ld\n", ch, best_pos )); 428 } 429 430 if ( fill ) 431 fills[num_fills++] = best_pos; 432 else 433 flats[num_flats++] = best_pos; 434 } 435 436 if ( num_flats == 0 && num_fills == 0 ) 437 { 438 /* 439 * we couldn't find a single glyph to compute this blue zone, 440 * we will simply ignore it then 441 */ 442 FT_TRACE5(( " empty\n" )); 443 continue; 444 } 445 446 /* we have computed the contents of the `fill' and `flats' tables, */ 447 /* now determine the reference and overshoot position of the blue -- */ 448 /* we simply take the median value after a simple sort */ 449 af_sort_pos( num_fills, fills ); 450 af_sort_pos( num_flats, flats ); 451 452 blue = &axis->blues[axis->blue_count]; 453 blue_ref = &blue->ref.org; 454 blue_shoot = &blue->shoot.org; 455 456 axis->blue_count++; 457 458 if ( num_flats == 0 ) 459 { 460 *blue_ref = 461 *blue_shoot = fills[num_fills / 2]; 462 } 463 else if ( num_fills == 0 ) 464 { 465 *blue_ref = 466 *blue_shoot = flats[num_flats / 2]; 467 } 468 else 469 { 470 *blue_ref = fills[num_fills / 2]; 471 *blue_shoot = flats[num_flats / 2]; 472 } 473 474 /* make sure blue_ref >= blue_shoot for top/right or */ 475 /* vice versa for bottom/left */ 476 if ( *blue_shoot != *blue_ref ) 477 { 478 FT_Pos ref = *blue_ref; 479 FT_Pos shoot = *blue_shoot; 480 FT_Bool under_ref = FT_BOOL( shoot < ref ); 481 482 483 /* AF_CJK_IS_TOP_BLUE covers `right' and `top' */ 484 if ( AF_CJK_IS_TOP_BLUE( bs ) ^ under_ref ) 485 { 486 *blue_ref = 487 *blue_shoot = ( shoot + ref ) / 2; 488 489 FT_TRACE5(( " [reference smaller than overshoot," 490 " taking mean value]\n" )); 491 } 492 } 493 494 blue->flags = 0; 495 if ( AF_CJK_IS_TOP_BLUE( bs ) ) 496 blue->flags |= AF_CJK_BLUE_TOP; 497 498 FT_TRACE5(( " -> reference = %ld\n" 499 " overshoot = %ld\n", 500 *blue_ref, *blue_shoot )); 501 } 502 503 FT_TRACE5(( "\n" )); 504 505 return; 506 } 507 508 509 /* Basically the Latin version with type AF_CJKMetrics for metrics. */ 510 511 FT_LOCAL_DEF( void ) 512 af_cjk_metrics_check_digits( AF_CJKMetrics metrics, 513 FT_Face face ) 514 { 515 FT_UInt i; 516 FT_Bool started = 0, same_width = 1; 517 FT_Fixed advance, old_advance = 0; 518 519 520 /* digit `0' is 0x30 in all supported charmaps */ 521 for ( i = 0x30; i <= 0x39; i++ ) 522 { 523 FT_ULong glyph_index; 524 FT_Long y_offset; 525 526 527 af_get_char_index( &metrics->root, i, &glyph_index, &y_offset ); 528 if ( glyph_index == 0 ) 529 continue; 530 531 if ( FT_Get_Advance( face, glyph_index, 532 FT_LOAD_NO_SCALE | 533 FT_LOAD_NO_HINTING | 534 FT_LOAD_IGNORE_TRANSFORM, 535 &advance ) ) 536 continue; 537 538 if ( started ) 539 { 540 if ( advance != old_advance ) 541 { 542 same_width = 0; 543 break; 544 } 545 } 546 else 547 { 548 old_advance = advance; 549 started = 1; 550 } 551 } 552 553 metrics->root.digits_have_same_width = same_width; 554 } 555 556 557 /* Initialize global metrics. */ 558 559 FT_LOCAL_DEF( FT_Error ) 560 af_cjk_metrics_init( AF_CJKMetrics metrics, 561 FT_Face face ) 562 { 563 FT_CharMap oldmap = face->charmap; 564 565 566 metrics->units_per_em = face->units_per_EM; 567 568 if ( !FT_Select_Charmap( face, FT_ENCODING_UNICODE ) ) 569 { 570 af_cjk_metrics_init_widths( metrics, face ); 571 af_cjk_metrics_init_blues( metrics, face ); 572 af_cjk_metrics_check_digits( metrics, face ); 573 } 574 575 FT_Set_Charmap( face, oldmap ); 576 return FT_Err_Ok; 577 } 578 579 580 /* Adjust scaling value, then scale and shift widths */ 581 /* and blue zones (if applicable) for given dimension. */ 582 583 static void 584 af_cjk_metrics_scale_dim( AF_CJKMetrics metrics, 585 AF_Scaler scaler, 586 AF_Dimension dim ) 587 { 588 FT_Fixed scale; 589 FT_Pos delta; 590 AF_CJKAxis axis; 591 FT_UInt nn; 592 593 594 if ( dim == AF_DIMENSION_HORZ ) 595 { 596 scale = scaler->x_scale; 597 delta = scaler->x_delta; 598 } 599 else 600 { 601 scale = scaler->y_scale; 602 delta = scaler->y_delta; 603 } 604 605 axis = &metrics->axis[dim]; 606 607 if ( axis->org_scale == scale && axis->org_delta == delta ) 608 return; 609 610 axis->org_scale = scale; 611 axis->org_delta = delta; 612 613 axis->scale = scale; 614 axis->delta = delta; 615 616 /* scale the blue zones */ 617 for ( nn = 0; nn < axis->blue_count; nn++ ) 618 { 619 AF_CJKBlue blue = &axis->blues[nn]; 620 FT_Pos dist; 621 622 623 blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta; 624 blue->ref.fit = blue->ref.cur; 625 blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta; 626 blue->shoot.fit = blue->shoot.cur; 627 blue->flags &= ~AF_CJK_BLUE_ACTIVE; 628 629 /* a blue zone is only active if it is less than 3/4 pixels tall */ 630 dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale ); 631 if ( dist <= 48 && dist >= -48 ) 632 { 633 FT_Pos delta1, delta2; 634 635 636 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); 637 638 /* shoot is under shoot for cjk */ 639 delta1 = FT_DivFix( blue->ref.fit, scale ) - blue->shoot.org; 640 delta2 = delta1; 641 if ( delta1 < 0 ) 642 delta2 = -delta2; 643 644 delta2 = FT_MulFix( delta2, scale ); 645 646 FT_TRACE5(( "delta: %d", delta1 )); 647 if ( delta2 < 32 ) 648 delta2 = 0; 649 #if 0 650 else if ( delta2 < 64 ) 651 delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 ); 652 #endif 653 else 654 delta2 = FT_PIX_ROUND( delta2 ); 655 FT_TRACE5(( "/%d\n", delta2 )); 656 657 if ( delta1 < 0 ) 658 delta2 = -delta2; 659 660 blue->shoot.fit = blue->ref.fit - delta2; 661 662 FT_TRACE5(( ">> active cjk blue zone %c%d[%ld/%ld]:\n" 663 " ref: cur=%.2f fit=%.2f\n" 664 " shoot: cur=%.2f fit=%.2f\n", 665 ( dim == AF_DIMENSION_HORZ ) ? 'H' : 'V', 666 nn, blue->ref.org, blue->shoot.org, 667 blue->ref.cur / 64.0, blue->ref.fit / 64.0, 668 blue->shoot.cur / 64.0, blue->shoot.fit / 64.0 )); 669 670 blue->flags |= AF_CJK_BLUE_ACTIVE; 671 } 672 } 673 } 674 675 676 /* Scale global values in both directions. */ 677 678 FT_LOCAL_DEF( void ) 679 af_cjk_metrics_scale( AF_CJKMetrics metrics, 680 AF_Scaler scaler ) 681 { 682 /* we copy the whole structure since the x and y scaling values */ 683 /* are not modified, contrary to e.g. the `latin' auto-hinter */ 684 metrics->root.scaler = *scaler; 685 686 af_cjk_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ ); 687 af_cjk_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT ); 688 } 689 690 691 /*************************************************************************/ 692 /*************************************************************************/ 693 /***** *****/ 694 /***** C J K G L Y P H A N A L Y S I S *****/ 695 /***** *****/ 696 /*************************************************************************/ 697 /*************************************************************************/ 698 699 700 /* Walk over all contours and compute its segments. */ 701 702 static FT_Error 703 af_cjk_hints_compute_segments( AF_GlyphHints hints, 704 AF_Dimension dim ) 705 { 706 AF_AxisHints axis = &hints->axis[dim]; 707 AF_Segment segments = axis->segments; 708 AF_Segment segment_limit = segments + axis->num_segments; 709 FT_Error error; 710 AF_Segment seg; 711 712 713 error = af_latin_hints_compute_segments( hints, dim ); 714 if ( error ) 715 return error; 716 717 /* a segment is round if it doesn't have successive */ 718 /* on-curve points. */ 719 for ( seg = segments; seg < segment_limit; seg++ ) 720 { 721 AF_Point pt = seg->first; 722 AF_Point last = seg->last; 723 AF_Flags f0 = (AF_Flags)( pt->flags & AF_FLAG_CONTROL ); 724 AF_Flags f1; 725 726 727 seg->flags &= ~AF_EDGE_ROUND; 728 729 for ( ; pt != last; f0 = f1 ) 730 { 731 pt = pt->next; 732 f1 = (AF_Flags)( pt->flags & AF_FLAG_CONTROL ); 733 734 if ( !f0 && !f1 ) 735 break; 736 737 if ( pt == last ) 738 seg->flags |= AF_EDGE_ROUND; 739 } 740 } 741 742 return FT_Err_Ok; 743 } 744 745 746 static void 747 af_cjk_hints_link_segments( AF_GlyphHints hints, 748 AF_Dimension dim ) 749 { 750 AF_AxisHints axis = &hints->axis[dim]; 751 AF_Segment segments = axis->segments; 752 AF_Segment segment_limit = segments + axis->num_segments; 753 AF_Direction major_dir = axis->major_dir; 754 AF_Segment seg1, seg2; 755 FT_Pos len_threshold; 756 FT_Pos dist_threshold; 757 758 759 len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 ); 760 761 dist_threshold = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale 762 : hints->y_scale; 763 dist_threshold = FT_DivFix( 64 * 3, dist_threshold ); 764 765 /* now compare each segment to the others */ 766 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 767 { 768 /* the fake segments are for metrics hinting only */ 769 if ( seg1->first == seg1->last ) 770 continue; 771 772 if ( seg1->dir != major_dir ) 773 continue; 774 775 for ( seg2 = segments; seg2 < segment_limit; seg2++ ) 776 if ( seg2 != seg1 && seg1->dir + seg2->dir == 0 ) 777 { 778 FT_Pos dist = seg2->pos - seg1->pos; 779 780 781 if ( dist < 0 ) 782 continue; 783 784 { 785 FT_Pos min = seg1->min_coord; 786 FT_Pos max = seg1->max_coord; 787 FT_Pos len; 788 789 790 if ( min < seg2->min_coord ) 791 min = seg2->min_coord; 792 793 if ( max > seg2->max_coord ) 794 max = seg2->max_coord; 795 796 len = max - min; 797 if ( len >= len_threshold ) 798 { 799 if ( dist * 8 < seg1->score * 9 && 800 ( dist * 8 < seg1->score * 7 || seg1->len < len ) ) 801 { 802 seg1->score = dist; 803 seg1->len = len; 804 seg1->link = seg2; 805 } 806 807 if ( dist * 8 < seg2->score * 9 && 808 ( dist * 8 < seg2->score * 7 || seg2->len < len ) ) 809 { 810 seg2->score = dist; 811 seg2->len = len; 812 seg2->link = seg1; 813 } 814 } 815 } 816 } 817 } 818 819 /* 820 * now compute the `serif' segments 821 * 822 * In Hanzi, some strokes are wider on one or both of the ends. 823 * We either identify the stems on the ends as serifs or remove 824 * the linkage, depending on the length of the stems. 825 * 826 */ 827 828 { 829 AF_Segment link1, link2; 830 831 832 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 833 { 834 link1 = seg1->link; 835 if ( !link1 || link1->link != seg1 || link1->pos <= seg1->pos ) 836 continue; 837 838 if ( seg1->score >= dist_threshold ) 839 continue; 840 841 for ( seg2 = segments; seg2 < segment_limit; seg2++ ) 842 { 843 if ( seg2->pos > seg1->pos || seg1 == seg2 ) 844 continue; 845 846 link2 = seg2->link; 847 if ( !link2 || link2->link != seg2 || link2->pos < link1->pos ) 848 continue; 849 850 if ( seg1->pos == seg2->pos && link1->pos == link2->pos ) 851 continue; 852 853 if ( seg2->score <= seg1->score || seg1->score * 4 <= seg2->score ) 854 continue; 855 856 /* seg2 < seg1 < link1 < link2 */ 857 858 if ( seg1->len >= seg2->len * 3 ) 859 { 860 AF_Segment seg; 861 862 863 for ( seg = segments; seg < segment_limit; seg++ ) 864 { 865 AF_Segment link = seg->link; 866 867 868 if ( link == seg2 ) 869 { 870 seg->link = 0; 871 seg->serif = link1; 872 } 873 else if ( link == link2 ) 874 { 875 seg->link = 0; 876 seg->serif = seg1; 877 } 878 } 879 } 880 else 881 { 882 seg1->link = link1->link = 0; 883 884 break; 885 } 886 } 887 } 888 } 889 890 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 891 { 892 seg2 = seg1->link; 893 894 if ( seg2 ) 895 { 896 seg2->num_linked++; 897 if ( seg2->link != seg1 ) 898 { 899 seg1->link = 0; 900 901 if ( seg2->score < dist_threshold || seg1->score < seg2->score * 4 ) 902 seg1->serif = seg2->link; 903 else 904 seg2->num_linked--; 905 } 906 } 907 } 908 } 909 910 911 static FT_Error 912 af_cjk_hints_compute_edges( AF_GlyphHints hints, 913 AF_Dimension dim ) 914 { 915 AF_AxisHints axis = &hints->axis[dim]; 916 FT_Error error = FT_Err_Ok; 917 FT_Memory memory = hints->memory; 918 AF_CJKAxis laxis = &((AF_CJKMetrics)hints->metrics)->axis[dim]; 919 920 AF_Segment segments = axis->segments; 921 AF_Segment segment_limit = segments + axis->num_segments; 922 AF_Segment seg; 923 924 FT_Fixed scale; 925 FT_Pos edge_distance_threshold; 926 927 928 axis->num_edges = 0; 929 930 scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale 931 : hints->y_scale; 932 933 /*********************************************************************/ 934 /* */ 935 /* We begin by generating a sorted table of edges for the current */ 936 /* direction. To do so, we simply scan each segment and try to find */ 937 /* an edge in our table that corresponds to its position. */ 938 /* */ 939 /* If no edge is found, we create and insert a new edge in the */ 940 /* sorted table. Otherwise, we simply add the segment to the edge's */ 941 /* list which is then processed in the second step to compute the */ 942 /* edge's properties. */ 943 /* */ 944 /* Note that the edges table is sorted along the segment/edge */ 945 /* position. */ 946 /* */ 947 /*********************************************************************/ 948 949 edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold, 950 scale ); 951 if ( edge_distance_threshold > 64 / 4 ) 952 edge_distance_threshold = FT_DivFix( 64 / 4, scale ); 953 else 954 edge_distance_threshold = laxis->edge_distance_threshold; 955 956 for ( seg = segments; seg < segment_limit; seg++ ) 957 { 958 AF_Edge found = NULL; 959 FT_Pos best = 0xFFFFU; 960 FT_Int ee; 961 962 963 /* look for an edge corresponding to the segment */ 964 for ( ee = 0; ee < axis->num_edges; ee++ ) 965 { 966 AF_Edge edge = axis->edges + ee; 967 FT_Pos dist; 968 969 970 if ( edge->dir != seg->dir ) 971 continue; 972 973 dist = seg->pos - edge->fpos; 974 if ( dist < 0 ) 975 dist = -dist; 976 977 if ( dist < edge_distance_threshold && dist < best ) 978 { 979 AF_Segment link = seg->link; 980 981 982 /* check whether all linked segments of the candidate edge */ 983 /* can make a single edge. */ 984 if ( link ) 985 { 986 AF_Segment seg1 = edge->first; 987 FT_Pos dist2 = 0; 988 989 990 do 991 { 992 AF_Segment link1 = seg1->link; 993 994 995 if ( link1 ) 996 { 997 dist2 = AF_SEGMENT_DIST( link, link1 ); 998 if ( dist2 >= edge_distance_threshold ) 999 break; 1000 } 1001 1002 } while ( ( seg1 = seg1->edge_next ) != edge->first ); 1003 1004 if ( dist2 >= edge_distance_threshold ) 1005 continue; 1006 } 1007 1008 best = dist; 1009 found = edge; 1010 } 1011 } 1012 1013 if ( !found ) 1014 { 1015 AF_Edge edge; 1016 1017 1018 /* insert a new edge in the list and */ 1019 /* sort according to the position */ 1020 error = af_axis_hints_new_edge( axis, seg->pos, 1021 (AF_Direction)seg->dir, 1022 memory, &edge ); 1023 if ( error ) 1024 goto Exit; 1025 1026 /* add the segment to the new edge's list */ 1027 FT_ZERO( edge ); 1028 1029 edge->first = seg; 1030 edge->last = seg; 1031 edge->fpos = seg->pos; 1032 edge->opos = edge->pos = FT_MulFix( seg->pos, scale ); 1033 seg->edge_next = seg; 1034 edge->dir = seg->dir; 1035 } 1036 else 1037 { 1038 /* if an edge was found, simply add the segment to the edge's */ 1039 /* list */ 1040 seg->edge_next = found->first; 1041 found->last->edge_next = seg; 1042 found->last = seg; 1043 } 1044 } 1045 1046 /******************************************************************/ 1047 /* */ 1048 /* Good, we now compute each edge's properties according to the */ 1049 /* segments found on its position. Basically, these are */ 1050 /* */ 1051 /* - the edge's main direction */ 1052 /* - stem edge, serif edge or both (which defaults to stem then) */ 1053 /* - rounded edge, straight or both (which defaults to straight) */ 1054 /* - link for edge */ 1055 /* */ 1056 /******************************************************************/ 1057 1058 /* first of all, set the `edge' field in each segment -- this is */ 1059 /* required in order to compute edge links */ 1060 1061 /* 1062 * Note that removing this loop and setting the `edge' field of each 1063 * segment directly in the code above slows down execution speed for 1064 * some reasons on platforms like the Sun. 1065 */ 1066 { 1067 AF_Edge edges = axis->edges; 1068 AF_Edge edge_limit = edges + axis->num_edges; 1069 AF_Edge edge; 1070 1071 1072 for ( edge = edges; edge < edge_limit; edge++ ) 1073 { 1074 seg = edge->first; 1075 if ( seg ) 1076 do 1077 { 1078 seg->edge = edge; 1079 seg = seg->edge_next; 1080 1081 } while ( seg != edge->first ); 1082 } 1083 1084 /* now compute each edge properties */ 1085 for ( edge = edges; edge < edge_limit; edge++ ) 1086 { 1087 FT_Int is_round = 0; /* does it contain round segments? */ 1088 FT_Int is_straight = 0; /* does it contain straight segments? */ 1089 1090 1091 seg = edge->first; 1092 1093 do 1094 { 1095 FT_Bool is_serif; 1096 1097 1098 /* check for roundness of segment */ 1099 if ( seg->flags & AF_EDGE_ROUND ) 1100 is_round++; 1101 else 1102 is_straight++; 1103 1104 /* check for links -- if seg->serif is set, then seg->link must */ 1105 /* be ignored */ 1106 is_serif = (FT_Bool)( seg->serif && seg->serif->edge != edge ); 1107 1108 if ( seg->link || is_serif ) 1109 { 1110 AF_Edge edge2; 1111 AF_Segment seg2; 1112 1113 1114 edge2 = edge->link; 1115 seg2 = seg->link; 1116 1117 if ( is_serif ) 1118 { 1119 seg2 = seg->serif; 1120 edge2 = edge->serif; 1121 } 1122 1123 if ( edge2 ) 1124 { 1125 FT_Pos edge_delta; 1126 FT_Pos seg_delta; 1127 1128 1129 edge_delta = edge->fpos - edge2->fpos; 1130 if ( edge_delta < 0 ) 1131 edge_delta = -edge_delta; 1132 1133 seg_delta = AF_SEGMENT_DIST( seg, seg2 ); 1134 1135 if ( seg_delta < edge_delta ) 1136 edge2 = seg2->edge; 1137 } 1138 else 1139 edge2 = seg2->edge; 1140 1141 if ( is_serif ) 1142 { 1143 edge->serif = edge2; 1144 edge2->flags |= AF_EDGE_SERIF; 1145 } 1146 else 1147 edge->link = edge2; 1148 } 1149 1150 seg = seg->edge_next; 1151 1152 } while ( seg != edge->first ); 1153 1154 /* set the round/straight flags */ 1155 edge->flags = AF_EDGE_NORMAL; 1156 1157 if ( is_round > 0 && is_round >= is_straight ) 1158 edge->flags |= AF_EDGE_ROUND; 1159 1160 /* get rid of serifs if link is set */ 1161 /* XXX: This gets rid of many unpleasant artefacts! */ 1162 /* Example: the `c' in cour.pfa at size 13 */ 1163 1164 if ( edge->serif && edge->link ) 1165 edge->serif = 0; 1166 } 1167 } 1168 1169 Exit: 1170 return error; 1171 } 1172 1173 1174 /* Detect segments and edges for given dimension. */ 1175 1176 static FT_Error 1177 af_cjk_hints_detect_features( AF_GlyphHints hints, 1178 AF_Dimension dim ) 1179 { 1180 FT_Error error; 1181 1182 1183 error = af_cjk_hints_compute_segments( hints, dim ); 1184 if ( !error ) 1185 { 1186 af_cjk_hints_link_segments( hints, dim ); 1187 1188 error = af_cjk_hints_compute_edges( hints, dim ); 1189 } 1190 return error; 1191 } 1192 1193 1194 /* Compute all edges which lie within blue zones. */ 1195 1196 FT_LOCAL_DEF( void ) 1197 af_cjk_hints_compute_blue_edges( AF_GlyphHints hints, 1198 AF_CJKMetrics metrics, 1199 AF_Dimension dim ) 1200 { 1201 AF_AxisHints axis = &hints->axis[dim]; 1202 AF_Edge edge = axis->edges; 1203 AF_Edge edge_limit = edge + axis->num_edges; 1204 AF_CJKAxis cjk = &metrics->axis[dim]; 1205 FT_Fixed scale = cjk->scale; 1206 FT_Pos best_dist0; /* initial threshold */ 1207 1208 1209 /* compute the initial threshold as a fraction of the EM size */ 1210 best_dist0 = FT_MulFix( metrics->units_per_em / 40, scale ); 1211 1212 if ( best_dist0 > 64 / 2 ) /* maximum 1/2 pixel */ 1213 best_dist0 = 64 / 2; 1214 1215 /* compute which blue zones are active, i.e. have their scaled */ 1216 /* size < 3/4 pixels */ 1217 1218 /* If the distant between an edge and a blue zone is shorter than */ 1219 /* best_dist0, set the blue zone for the edge. Then search for */ 1220 /* the blue zone with the smallest best_dist to the edge. */ 1221 1222 for ( ; edge < edge_limit; edge++ ) 1223 { 1224 FT_UInt bb; 1225 AF_Width best_blue = NULL; 1226 FT_Pos best_dist = best_dist0; 1227 1228 1229 for ( bb = 0; bb < cjk->blue_count; bb++ ) 1230 { 1231 AF_CJKBlue blue = cjk->blues + bb; 1232 FT_Bool is_top_right_blue, is_major_dir; 1233 1234 1235 /* skip inactive blue zones (i.e., those that are too small) */ 1236 if ( !( blue->flags & AF_CJK_BLUE_ACTIVE ) ) 1237 continue; 1238 1239 /* if it is a top zone, check for right edges -- if it is a bottom */ 1240 /* zone, check for left edges */ 1241 /* */ 1242 /* of course, that's for TrueType */ 1243 is_top_right_blue = 1244 (FT_Byte)( ( blue->flags & AF_CJK_BLUE_TOP ) != 0 ); 1245 is_major_dir = 1246 FT_BOOL( edge->dir == axis->major_dir ); 1247 1248 /* if it is a top zone, the edge must be against the major */ 1249 /* direction; if it is a bottom zone, it must be in the major */ 1250 /* direction */ 1251 if ( is_top_right_blue ^ is_major_dir ) 1252 { 1253 FT_Pos dist; 1254 AF_Width compare; 1255 1256 1257 /* Compare the edge to the closest blue zone type */ 1258 if ( FT_ABS( edge->fpos - blue->ref.org ) > 1259 FT_ABS( edge->fpos - blue->shoot.org ) ) 1260 compare = &blue->shoot; 1261 else 1262 compare = &blue->ref; 1263 1264 dist = edge->fpos - compare->org; 1265 if ( dist < 0 ) 1266 dist = -dist; 1267 1268 dist = FT_MulFix( dist, scale ); 1269 if ( dist < best_dist ) 1270 { 1271 best_dist = dist; 1272 best_blue = compare; 1273 } 1274 } 1275 } 1276 1277 if ( best_blue ) 1278 edge->blue_edge = best_blue; 1279 } 1280 } 1281 1282 1283 /* Initalize hinting engine. */ 1284 1285 FT_LOCAL_DEF( FT_Error ) 1286 af_cjk_hints_init( AF_GlyphHints hints, 1287 AF_CJKMetrics metrics ) 1288 { 1289 FT_Render_Mode mode; 1290 FT_UInt32 scaler_flags, other_flags; 1291 1292 1293 af_glyph_hints_rescale( hints, (AF_StyleMetrics)metrics ); 1294 1295 /* 1296 * correct x_scale and y_scale when needed, since they may have 1297 * been modified af_cjk_scale_dim above 1298 */ 1299 hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale; 1300 hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta; 1301 hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale; 1302 hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta; 1303 1304 /* compute flags depending on render mode, etc. */ 1305 mode = metrics->root.scaler.render_mode; 1306 1307 #ifdef AF_CONFIG_OPTION_USE_WARPER 1308 if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V ) 1309 metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL; 1310 #endif 1311 1312 scaler_flags = hints->scaler_flags; 1313 other_flags = 0; 1314 1315 /* 1316 * We snap the width of vertical stems for the monochrome and 1317 * horizontal LCD rendering targets only. 1318 */ 1319 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD ) 1320 other_flags |= AF_LATIN_HINTS_HORZ_SNAP; 1321 1322 /* 1323 * We snap the width of horizontal stems for the monochrome and 1324 * vertical LCD rendering targets only. 1325 */ 1326 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V ) 1327 other_flags |= AF_LATIN_HINTS_VERT_SNAP; 1328 1329 /* 1330 * We adjust stems to full pixels only if we don't use the `light' mode. 1331 */ 1332 if ( mode != FT_RENDER_MODE_LIGHT ) 1333 other_flags |= AF_LATIN_HINTS_STEM_ADJUST; 1334 1335 if ( mode == FT_RENDER_MODE_MONO ) 1336 other_flags |= AF_LATIN_HINTS_MONO; 1337 1338 scaler_flags |= AF_SCALER_FLAG_NO_ADVANCE; 1339 1340 hints->scaler_flags = scaler_flags; 1341 hints->other_flags = other_flags; 1342 1343 return FT_Err_Ok; 1344 } 1345 1346 1347 /*************************************************************************/ 1348 /*************************************************************************/ 1349 /***** *****/ 1350 /***** C J K G L Y P H G R I D - F I T T I N G *****/ 1351 /***** *****/ 1352 /*************************************************************************/ 1353 /*************************************************************************/ 1354 1355 /* Snap a given width in scaled coordinates to one of the */ 1356 /* current standard widths. */ 1357 1358 static FT_Pos 1359 af_cjk_snap_width( AF_Width widths, 1360 FT_Int count, 1361 FT_Pos width ) 1362 { 1363 int n; 1364 FT_Pos best = 64 + 32 + 2; 1365 FT_Pos reference = width; 1366 FT_Pos scaled; 1367 1368 1369 for ( n = 0; n < count; n++ ) 1370 { 1371 FT_Pos w; 1372 FT_Pos dist; 1373 1374 1375 w = widths[n].cur; 1376 dist = width - w; 1377 if ( dist < 0 ) 1378 dist = -dist; 1379 if ( dist < best ) 1380 { 1381 best = dist; 1382 reference = w; 1383 } 1384 } 1385 1386 scaled = FT_PIX_ROUND( reference ); 1387 1388 if ( width >= reference ) 1389 { 1390 if ( width < scaled + 48 ) 1391 width = reference; 1392 } 1393 else 1394 { 1395 if ( width > scaled - 48 ) 1396 width = reference; 1397 } 1398 1399 return width; 1400 } 1401 1402 1403 /* Compute the snapped width of a given stem. */ 1404 /* There is a lot of voodoo in this function; changing the hard-coded */ 1405 /* parameters influence the whole hinting process. */ 1406 1407 static FT_Pos 1408 af_cjk_compute_stem_width( AF_GlyphHints hints, 1409 AF_Dimension dim, 1410 FT_Pos width, 1411 AF_Edge_Flags base_flags, 1412 AF_Edge_Flags stem_flags ) 1413 { 1414 AF_CJKMetrics metrics = (AF_CJKMetrics)hints->metrics; 1415 AF_CJKAxis axis = &metrics->axis[dim]; 1416 FT_Pos dist = width; 1417 FT_Int sign = 0; 1418 FT_Bool vertical = FT_BOOL( dim == AF_DIMENSION_VERT ); 1419 1420 FT_UNUSED( base_flags ); 1421 FT_UNUSED( stem_flags ); 1422 1423 1424 if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) ) 1425 return width; 1426 1427 if ( dist < 0 ) 1428 { 1429 dist = -width; 1430 sign = 1; 1431 } 1432 1433 if ( ( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) || 1434 ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) ) 1435 { 1436 /* smooth hinting process: very lightly quantize the stem width */ 1437 1438 if ( axis->width_count > 0 ) 1439 { 1440 if ( FT_ABS( dist - axis->widths[0].cur ) < 40 ) 1441 { 1442 dist = axis->widths[0].cur; 1443 if ( dist < 48 ) 1444 dist = 48; 1445 1446 goto Done_Width; 1447 } 1448 } 1449 1450 if ( dist < 54 ) 1451 dist += ( 54 - dist ) / 2 ; 1452 else if ( dist < 3 * 64 ) 1453 { 1454 FT_Pos delta; 1455 1456 1457 delta = dist & 63; 1458 dist &= -64; 1459 1460 if ( delta < 10 ) 1461 dist += delta; 1462 else if ( delta < 22 ) 1463 dist += 10; 1464 else if ( delta < 42 ) 1465 dist += delta; 1466 else if ( delta < 54 ) 1467 dist += 54; 1468 else 1469 dist += delta; 1470 } 1471 } 1472 else 1473 { 1474 /* strong hinting process: snap the stem width to integer pixels */ 1475 1476 dist = af_cjk_snap_width( axis->widths, axis->width_count, dist ); 1477 1478 if ( vertical ) 1479 { 1480 /* in the case of vertical hinting, always round */ 1481 /* the stem heights to integer pixels */ 1482 1483 if ( dist >= 64 ) 1484 dist = ( dist + 16 ) & ~63; 1485 else 1486 dist = 64; 1487 } 1488 else 1489 { 1490 if ( AF_LATIN_HINTS_DO_MONO( hints ) ) 1491 { 1492 /* monochrome horizontal hinting: snap widths to integer pixels */ 1493 /* with a different threshold */ 1494 1495 if ( dist < 64 ) 1496 dist = 64; 1497 else 1498 dist = ( dist + 32 ) & ~63; 1499 } 1500 else 1501 { 1502 /* for horizontal anti-aliased hinting, we adopt a more subtle */ 1503 /* approach: we strengthen small stems, round stems whose size */ 1504 /* is between 1 and 2 pixels to an integer, otherwise nothing */ 1505 1506 if ( dist < 48 ) 1507 dist = ( dist + 64 ) >> 1; 1508 1509 else if ( dist < 128 ) 1510 dist = ( dist + 22 ) & ~63; 1511 else 1512 /* round otherwise to prevent color fringes in LCD mode */ 1513 dist = ( dist + 32 ) & ~63; 1514 } 1515 } 1516 } 1517 1518 Done_Width: 1519 if ( sign ) 1520 dist = -dist; 1521 1522 return dist; 1523 } 1524 1525 1526 /* Align one stem edge relative to the previous stem edge. */ 1527 1528 static void 1529 af_cjk_align_linked_edge( AF_GlyphHints hints, 1530 AF_Dimension dim, 1531 AF_Edge base_edge, 1532 AF_Edge stem_edge ) 1533 { 1534 FT_Pos dist = stem_edge->opos - base_edge->opos; 1535 1536 FT_Pos fitted_width = af_cjk_compute_stem_width( 1537 hints, dim, dist, 1538 (AF_Edge_Flags)base_edge->flags, 1539 (AF_Edge_Flags)stem_edge->flags ); 1540 1541 1542 stem_edge->pos = base_edge->pos + fitted_width; 1543 1544 FT_TRACE5(( " CJKLINK: edge %d @%d (opos=%.2f) linked to %.2f," 1545 " dist was %.2f, now %.2f\n", 1546 stem_edge - hints->axis[dim].edges, stem_edge->fpos, 1547 stem_edge->opos / 64.0, stem_edge->pos / 64.0, 1548 dist / 64.0, fitted_width / 64.0 )); 1549 } 1550 1551 1552 /* Shift the coordinates of the `serif' edge by the same amount */ 1553 /* as the corresponding `base' edge has been moved already. */ 1554 1555 static void 1556 af_cjk_align_serif_edge( AF_GlyphHints hints, 1557 AF_Edge base, 1558 AF_Edge serif ) 1559 { 1560 FT_UNUSED( hints ); 1561 1562 serif->pos = base->pos + ( serif->opos - base->opos ); 1563 } 1564 1565 1566 /*************************************************************************/ 1567 /*************************************************************************/ 1568 /*************************************************************************/ 1569 /**** ****/ 1570 /**** E D G E H I N T I N G ****/ 1571 /**** ****/ 1572 /*************************************************************************/ 1573 /*************************************************************************/ 1574 /*************************************************************************/ 1575 1576 1577 #define AF_LIGHT_MODE_MAX_HORZ_GAP 9 1578 #define AF_LIGHT_MODE_MAX_VERT_GAP 15 1579 #define AF_LIGHT_MODE_MAX_DELTA_ABS 14 1580 1581 1582 static FT_Pos 1583 af_hint_normal_stem( AF_GlyphHints hints, 1584 AF_Edge edge, 1585 AF_Edge edge2, 1586 FT_Pos anchor, 1587 AF_Dimension dim ) 1588 { 1589 FT_Pos org_len, cur_len, org_center; 1590 FT_Pos cur_pos1, cur_pos2; 1591 FT_Pos d_off1, u_off1, d_off2, u_off2, delta; 1592 FT_Pos offset; 1593 FT_Pos threshold = 64; 1594 1595 1596 if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) ) 1597 { 1598 if ( ( edge->flags & AF_EDGE_ROUND ) && 1599 ( edge2->flags & AF_EDGE_ROUND ) ) 1600 { 1601 if ( dim == AF_DIMENSION_VERT ) 1602 threshold = 64 - AF_LIGHT_MODE_MAX_HORZ_GAP; 1603 else 1604 threshold = 64 - AF_LIGHT_MODE_MAX_VERT_GAP; 1605 } 1606 else 1607 { 1608 if ( dim == AF_DIMENSION_VERT ) 1609 threshold = 64 - AF_LIGHT_MODE_MAX_HORZ_GAP / 3; 1610 else 1611 threshold = 64 - AF_LIGHT_MODE_MAX_VERT_GAP / 3; 1612 } 1613 } 1614 1615 org_len = edge2->opos - edge->opos; 1616 cur_len = af_cjk_compute_stem_width( hints, dim, org_len, 1617 (AF_Edge_Flags)edge->flags, 1618 (AF_Edge_Flags)edge2->flags ); 1619 1620 org_center = ( edge->opos + edge2->opos ) / 2 + anchor; 1621 cur_pos1 = org_center - cur_len / 2; 1622 cur_pos2 = cur_pos1 + cur_len; 1623 d_off1 = cur_pos1 - FT_PIX_FLOOR( cur_pos1 ); 1624 d_off2 = cur_pos2 - FT_PIX_FLOOR( cur_pos2 ); 1625 u_off1 = 64 - d_off1; 1626 u_off2 = 64 - d_off2; 1627 delta = 0; 1628 1629 1630 if ( d_off1 == 0 || d_off2 == 0 ) 1631 goto Exit; 1632 1633 if ( cur_len <= threshold ) 1634 { 1635 if ( d_off2 < cur_len ) 1636 { 1637 if ( u_off1 <= d_off2 ) 1638 delta = u_off1; 1639 else 1640 delta = -d_off2; 1641 } 1642 1643 goto Exit; 1644 } 1645 1646 if ( threshold < 64 ) 1647 { 1648 if ( d_off1 >= threshold || u_off1 >= threshold || 1649 d_off2 >= threshold || u_off2 >= threshold ) 1650 goto Exit; 1651 } 1652 1653 offset = cur_len & 63; 1654 1655 if ( offset < 32 ) 1656 { 1657 if ( u_off1 <= offset || d_off2 <= offset ) 1658 goto Exit; 1659 } 1660 else 1661 offset = 64 - threshold; 1662 1663 d_off1 = threshold - u_off1; 1664 u_off1 = u_off1 - offset; 1665 u_off2 = threshold - d_off2; 1666 d_off2 = d_off2 - offset; 1667 1668 if ( d_off1 <= u_off1 ) 1669 u_off1 = -d_off1; 1670 1671 if ( d_off2 <= u_off2 ) 1672 u_off2 = -d_off2; 1673 1674 if ( FT_ABS( u_off1 ) <= FT_ABS( u_off2 ) ) 1675 delta = u_off1; 1676 else 1677 delta = u_off2; 1678 1679 Exit: 1680 1681 #if 1 1682 if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) ) 1683 { 1684 if ( delta > AF_LIGHT_MODE_MAX_DELTA_ABS ) 1685 delta = AF_LIGHT_MODE_MAX_DELTA_ABS; 1686 else if ( delta < -AF_LIGHT_MODE_MAX_DELTA_ABS ) 1687 delta = -AF_LIGHT_MODE_MAX_DELTA_ABS; 1688 } 1689 #endif 1690 1691 cur_pos1 += delta; 1692 1693 if ( edge->opos < edge2->opos ) 1694 { 1695 edge->pos = cur_pos1; 1696 edge2->pos = cur_pos1 + cur_len; 1697 } 1698 else 1699 { 1700 edge->pos = cur_pos1 + cur_len; 1701 edge2->pos = cur_pos1; 1702 } 1703 1704 return delta; 1705 } 1706 1707 1708 /* The main grid-fitting routine. */ 1709 1710 static void 1711 af_cjk_hint_edges( AF_GlyphHints hints, 1712 AF_Dimension dim ) 1713 { 1714 AF_AxisHints axis = &hints->axis[dim]; 1715 AF_Edge edges = axis->edges; 1716 AF_Edge edge_limit = edges + axis->num_edges; 1717 FT_PtrDist n_edges; 1718 AF_Edge edge; 1719 AF_Edge anchor = 0; 1720 FT_Pos delta = 0; 1721 FT_Int skipped = 0; 1722 FT_Bool has_last_stem = FALSE; 1723 FT_Pos last_stem_pos = 0; 1724 1725 #ifdef FT_DEBUG_LEVEL_TRACE 1726 FT_UInt num_actions = 0; 1727 #endif 1728 1729 1730 FT_TRACE5(( "cjk %s edge hinting (style `%s')\n", 1731 dim == AF_DIMENSION_VERT ? "horizontal" : "vertical", 1732 af_style_names[hints->metrics->style_class->style] )); 1733 1734 /* we begin by aligning all stems relative to the blue zone */ 1735 1736 if ( AF_HINTS_DO_BLUES( hints ) ) 1737 { 1738 for ( edge = edges; edge < edge_limit; edge++ ) 1739 { 1740 AF_Width blue; 1741 AF_Edge edge1, edge2; 1742 1743 1744 if ( edge->flags & AF_EDGE_DONE ) 1745 continue; 1746 1747 blue = edge->blue_edge; 1748 edge1 = NULL; 1749 edge2 = edge->link; 1750 1751 if ( blue ) 1752 { 1753 edge1 = edge; 1754 } 1755 else if ( edge2 && edge2->blue_edge ) 1756 { 1757 blue = edge2->blue_edge; 1758 edge1 = edge2; 1759 edge2 = edge; 1760 } 1761 1762 if ( !edge1 ) 1763 continue; 1764 1765 #ifdef FT_DEBUG_LEVEL_TRACE 1766 FT_TRACE5(( " CJKBLUE: edge %d @%d (opos=%.2f) snapped to %.2f," 1767 " was %.2f\n", 1768 edge1 - edges, edge1->fpos, edge1->opos / 64.0, 1769 blue->fit / 64.0, edge1->pos / 64.0 )); 1770 1771 num_actions++; 1772 #endif 1773 1774 edge1->pos = blue->fit; 1775 edge1->flags |= AF_EDGE_DONE; 1776 1777 if ( edge2 && !edge2->blue_edge ) 1778 { 1779 af_cjk_align_linked_edge( hints, dim, edge1, edge2 ); 1780 edge2->flags |= AF_EDGE_DONE; 1781 1782 #ifdef FT_DEBUG_LEVEL_TRACE 1783 num_actions++; 1784 #endif 1785 } 1786 1787 if ( !anchor ) 1788 anchor = edge; 1789 } 1790 } 1791 1792 /* now we align all stem edges. */ 1793 for ( edge = edges; edge < edge_limit; edge++ ) 1794 { 1795 AF_Edge edge2; 1796 1797 1798 if ( edge->flags & AF_EDGE_DONE ) 1799 continue; 1800 1801 /* skip all non-stem edges */ 1802 edge2 = edge->link; 1803 if ( !edge2 ) 1804 { 1805 skipped++; 1806 continue; 1807 } 1808 1809 /* Some CJK characters have so many stems that 1810 * the hinter is likely to merge two adjacent ones. 1811 * To solve this problem, if either edge of a stem 1812 * is too close to the previous one, we avoid 1813 * aligning the two edges, but rather interpolate 1814 * their locations at the end of this function in 1815 * order to preserve the space between the stems. 1816 */ 1817 if ( has_last_stem && 1818 ( edge->pos < last_stem_pos + 64 || 1819 edge2->pos < last_stem_pos + 64 ) ) 1820 { 1821 skipped++; 1822 continue; 1823 } 1824 1825 /* now align the stem */ 1826 1827 /* this should not happen, but it's better to be safe */ 1828 if ( edge2->blue_edge ) 1829 { 1830 FT_TRACE5(( "ASSERTION FAILED for edge %d\n", edge2-edges )); 1831 1832 af_cjk_align_linked_edge( hints, dim, edge2, edge ); 1833 edge->flags |= AF_EDGE_DONE; 1834 1835 #ifdef FT_DEBUG_LEVEL_TRACE 1836 num_actions++; 1837 #endif 1838 1839 continue; 1840 } 1841 1842 if ( edge2 < edge ) 1843 { 1844 af_cjk_align_linked_edge( hints, dim, edge2, edge ); 1845 edge->flags |= AF_EDGE_DONE; 1846 1847 #ifdef FT_DEBUG_LEVEL_TRACE 1848 num_actions++; 1849 #endif 1850 1851 /* We rarely reaches here it seems; 1852 * usually the two edges belonging 1853 * to one stem are marked as DONE together 1854 */ 1855 has_last_stem = TRUE; 1856 last_stem_pos = edge->pos; 1857 continue; 1858 } 1859 1860 if ( dim != AF_DIMENSION_VERT && !anchor ) 1861 { 1862 1863 #if 0 1864 if ( fixedpitch ) 1865 { 1866 AF_Edge left = edge; 1867 AF_Edge right = edge_limit - 1; 1868 AF_EdgeRec left1, left2, right1, right2; 1869 FT_Pos target, center1, center2; 1870 FT_Pos delta1, delta2, d1, d2; 1871 1872 1873 while ( right > left && !right->link ) 1874 right--; 1875 1876 left1 = *left; 1877 left2 = *left->link; 1878 right1 = *right->link; 1879 right2 = *right; 1880 1881 delta = ( ( ( hinter->pp2.x + 32 ) & -64 ) - hinter->pp2.x ) / 2; 1882 target = left->opos + ( right->opos - left->opos ) / 2 + delta - 16; 1883 1884 delta1 = delta; 1885 delta1 += af_hint_normal_stem( hints, left, left->link, 1886 delta1, 0 ); 1887 1888 if ( left->link != right ) 1889 af_hint_normal_stem( hints, right->link, right, delta1, 0 ); 1890 1891 center1 = left->pos + ( right->pos - left->pos ) / 2; 1892 1893 if ( center1 >= target ) 1894 delta2 = delta - 32; 1895 else 1896 delta2 = delta + 32; 1897 1898 delta2 += af_hint_normal_stem( hints, &left1, &left2, delta2, 0 ); 1899 1900 if ( delta1 != delta2 ) 1901 { 1902 if ( left->link != right ) 1903 af_hint_normal_stem( hints, &right1, &right2, delta2, 0 ); 1904 1905 center2 = left1.pos + ( right2.pos - left1.pos ) / 2; 1906 1907 d1 = center1 - target; 1908 d2 = center2 - target; 1909 1910 if ( FT_ABS( d2 ) < FT_ABS( d1 ) ) 1911 { 1912 left->pos = left1.pos; 1913 left->link->pos = left2.pos; 1914 1915 if ( left->link != right ) 1916 { 1917 right->link->pos = right1.pos; 1918 right->pos = right2.pos; 1919 } 1920 1921 delta1 = delta2; 1922 } 1923 } 1924 1925 delta = delta1; 1926 right->link->flags |= AF_EDGE_DONE; 1927 right->flags |= AF_EDGE_DONE; 1928 } 1929 else 1930 1931 #endif /* 0 */ 1932 1933 delta = af_hint_normal_stem( hints, edge, edge2, 0, 1934 AF_DIMENSION_HORZ ); 1935 } 1936 else 1937 af_hint_normal_stem( hints, edge, edge2, delta, dim ); 1938 1939 #if 0 1940 printf( "stem (%d,%d) adjusted (%.1f,%.1f)\n", 1941 edge - edges, edge2 - edges, 1942 ( edge->pos - edge->opos ) / 64.0, 1943 ( edge2->pos - edge2->opos ) / 64.0 ); 1944 #endif 1945 1946 anchor = edge; 1947 edge->flags |= AF_EDGE_DONE; 1948 edge2->flags |= AF_EDGE_DONE; 1949 has_last_stem = TRUE; 1950 last_stem_pos = edge2->pos; 1951 } 1952 1953 /* make sure that lowercase m's maintain their symmetry */ 1954 1955 /* In general, lowercase m's have six vertical edges if they are sans */ 1956 /* serif, or twelve if they are with serifs. This implementation is */ 1957 /* based on that assumption, and seems to work very well with most */ 1958 /* faces. However, if for a certain face this assumption is not */ 1959 /* true, the m is just rendered like before. In addition, any stem */ 1960 /* correction will only be applied to symmetrical glyphs (even if the */ 1961 /* glyph is not an m), so the potential for unwanted distortion is */ 1962 /* relatively low. */ 1963 1964 /* We don't handle horizontal edges since we can't easily assure that */ 1965 /* the third (lowest) stem aligns with the base line; it might end up */ 1966 /* one pixel higher or lower. */ 1967 1968 n_edges = edge_limit - edges; 1969 if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) ) 1970 { 1971 AF_Edge edge1, edge2, edge3; 1972 FT_Pos dist1, dist2, span; 1973 1974 1975 if ( n_edges == 6 ) 1976 { 1977 edge1 = edges; 1978 edge2 = edges + 2; 1979 edge3 = edges + 4; 1980 } 1981 else 1982 { 1983 edge1 = edges + 1; 1984 edge2 = edges + 5; 1985 edge3 = edges + 9; 1986 } 1987 1988 dist1 = edge2->opos - edge1->opos; 1989 dist2 = edge3->opos - edge2->opos; 1990 1991 span = dist1 - dist2; 1992 if ( span < 0 ) 1993 span = -span; 1994 1995 if ( edge1->link == edge1 + 1 && 1996 edge2->link == edge2 + 1 && 1997 edge3->link == edge3 + 1 && span < 8 ) 1998 { 1999 delta = edge3->pos - ( 2 * edge2->pos - edge1->pos ); 2000 edge3->pos -= delta; 2001 if ( edge3->link ) 2002 edge3->link->pos -= delta; 2003 2004 /* move the serifs along with the stem */ 2005 if ( n_edges == 12 ) 2006 { 2007 ( edges + 8 )->pos -= delta; 2008 ( edges + 11 )->pos -= delta; 2009 } 2010 2011 edge3->flags |= AF_EDGE_DONE; 2012 if ( edge3->link ) 2013 edge3->link->flags |= AF_EDGE_DONE; 2014 } 2015 } 2016 2017 if ( !skipped ) 2018 goto Exit; 2019 2020 /* 2021 * now hint the remaining edges (serifs and single) in order 2022 * to complete our processing 2023 */ 2024 for ( edge = edges; edge < edge_limit; edge++ ) 2025 { 2026 if ( edge->flags & AF_EDGE_DONE ) 2027 continue; 2028 2029 if ( edge->serif ) 2030 { 2031 af_cjk_align_serif_edge( hints, edge->serif, edge ); 2032 edge->flags |= AF_EDGE_DONE; 2033 skipped--; 2034 } 2035 } 2036 2037 if ( !skipped ) 2038 goto Exit; 2039 2040 for ( edge = edges; edge < edge_limit; edge++ ) 2041 { 2042 AF_Edge before, after; 2043 2044 2045 if ( edge->flags & AF_EDGE_DONE ) 2046 continue; 2047 2048 before = after = edge; 2049 2050 while ( --before >= edges ) 2051 if ( before->flags & AF_EDGE_DONE ) 2052 break; 2053 2054 while ( ++after < edge_limit ) 2055 if ( after->flags & AF_EDGE_DONE ) 2056 break; 2057 2058 if ( before >= edges || after < edge_limit ) 2059 { 2060 if ( before < edges ) 2061 af_cjk_align_serif_edge( hints, after, edge ); 2062 else if ( after >= edge_limit ) 2063 af_cjk_align_serif_edge( hints, before, edge ); 2064 else 2065 { 2066 if ( after->fpos == before->fpos ) 2067 edge->pos = before->pos; 2068 else 2069 edge->pos = before->pos + 2070 FT_MulDiv( edge->fpos - before->fpos, 2071 after->pos - before->pos, 2072 after->fpos - before->fpos ); 2073 } 2074 } 2075 } 2076 2077 Exit: 2078 2079 #ifdef FT_DEBUG_LEVEL_TRACE 2080 if ( !num_actions ) 2081 FT_TRACE5(( " (none)\n" )); 2082 FT_TRACE5(( "\n" )); 2083 #endif 2084 2085 return; 2086 } 2087 2088 2089 static void 2090 af_cjk_align_edge_points( AF_GlyphHints hints, 2091 AF_Dimension dim ) 2092 { 2093 AF_AxisHints axis = & hints->axis[dim]; 2094 AF_Edge edges = axis->edges; 2095 AF_Edge edge_limit = edges + axis->num_edges; 2096 AF_Edge edge; 2097 FT_Bool snapping; 2098 2099 2100 snapping = FT_BOOL( ( dim == AF_DIMENSION_HORZ && 2101 AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) || 2102 ( dim == AF_DIMENSION_VERT && 2103 AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) ); 2104 2105 for ( edge = edges; edge < edge_limit; edge++ ) 2106 { 2107 /* move the points of each segment */ 2108 /* in each edge to the edge's position */ 2109 AF_Segment seg = edge->first; 2110 2111 2112 if ( snapping ) 2113 { 2114 do 2115 { 2116 AF_Point point = seg->first; 2117 2118 2119 for (;;) 2120 { 2121 if ( dim == AF_DIMENSION_HORZ ) 2122 { 2123 point->x = edge->pos; 2124 point->flags |= AF_FLAG_TOUCH_X; 2125 } 2126 else 2127 { 2128 point->y = edge->pos; 2129 point->flags |= AF_FLAG_TOUCH_Y; 2130 } 2131 2132 if ( point == seg->last ) 2133 break; 2134 2135 point = point->next; 2136 } 2137 2138 seg = seg->edge_next; 2139 2140 } while ( seg != edge->first ); 2141 } 2142 else 2143 { 2144 FT_Pos delta = edge->pos - edge->opos; 2145 2146 2147 do 2148 { 2149 AF_Point point = seg->first; 2150 2151 2152 for (;;) 2153 { 2154 if ( dim == AF_DIMENSION_HORZ ) 2155 { 2156 point->x += delta; 2157 point->flags |= AF_FLAG_TOUCH_X; 2158 } 2159 else 2160 { 2161 point->y += delta; 2162 point->flags |= AF_FLAG_TOUCH_Y; 2163 } 2164 2165 if ( point == seg->last ) 2166 break; 2167 2168 point = point->next; 2169 } 2170 2171 seg = seg->edge_next; 2172 2173 } while ( seg != edge->first ); 2174 } 2175 } 2176 } 2177 2178 2179 /* Apply the complete hinting algorithm to a CJK glyph. */ 2180 2181 FT_LOCAL_DEF( FT_Error ) 2182 af_cjk_hints_apply( AF_GlyphHints hints, 2183 FT_Outline* outline, 2184 AF_CJKMetrics metrics ) 2185 { 2186 FT_Error error; 2187 int dim; 2188 2189 FT_UNUSED( metrics ); 2190 2191 2192 error = af_glyph_hints_reload( hints, outline ); 2193 if ( error ) 2194 goto Exit; 2195 2196 /* analyze glyph outline */ 2197 if ( AF_HINTS_DO_HORIZONTAL( hints ) ) 2198 { 2199 error = af_cjk_hints_detect_features( hints, AF_DIMENSION_HORZ ); 2200 if ( error ) 2201 goto Exit; 2202 2203 af_cjk_hints_compute_blue_edges( hints, metrics, AF_DIMENSION_HORZ ); 2204 } 2205 2206 if ( AF_HINTS_DO_VERTICAL( hints ) ) 2207 { 2208 error = af_cjk_hints_detect_features( hints, AF_DIMENSION_VERT ); 2209 if ( error ) 2210 goto Exit; 2211 2212 af_cjk_hints_compute_blue_edges( hints, metrics, AF_DIMENSION_VERT ); 2213 } 2214 2215 /* grid-fit the outline */ 2216 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 2217 { 2218 if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) || 2219 ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) ) ) 2220 { 2221 2222 #ifdef AF_CONFIG_OPTION_USE_WARPER 2223 if ( dim == AF_DIMENSION_HORZ && 2224 metrics->root.scaler.render_mode == FT_RENDER_MODE_NORMAL ) 2225 { 2226 AF_WarperRec warper; 2227 FT_Fixed scale; 2228 FT_Pos delta; 2229 2230 2231 af_warper_compute( &warper, hints, (AF_Dimension)dim, 2232 &scale, &delta ); 2233 af_glyph_hints_scale_dim( hints, (AF_Dimension)dim, 2234 scale, delta ); 2235 continue; 2236 } 2237 #endif /* AF_CONFIG_OPTION_USE_WARPER */ 2238 2239 af_cjk_hint_edges( hints, (AF_Dimension)dim ); 2240 af_cjk_align_edge_points( hints, (AF_Dimension)dim ); 2241 af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim ); 2242 af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim ); 2243 } 2244 } 2245 2246 #if 0 2247 af_glyph_hints_dump_points( hints ); 2248 af_glyph_hints_dump_segments( hints ); 2249 af_glyph_hints_dump_edges( hints ); 2250 #endif 2251 2252 af_glyph_hints_save( hints, outline ); 2253 2254 Exit: 2255 return error; 2256 } 2257 2258 2259 /*************************************************************************/ 2260 /*************************************************************************/ 2261 /***** *****/ 2262 /***** C J K S C R I P T C L A S S *****/ 2263 /***** *****/ 2264 /*************************************************************************/ 2265 /*************************************************************************/ 2266 2267 2268 AF_DEFINE_WRITING_SYSTEM_CLASS( 2269 af_cjk_writing_system_class, 2270 2271 AF_WRITING_SYSTEM_CJK, 2272 2273 sizeof ( AF_CJKMetricsRec ), 2274 2275 (AF_WritingSystem_InitMetricsFunc) af_cjk_metrics_init, 2276 (AF_WritingSystem_ScaleMetricsFunc)af_cjk_metrics_scale, 2277 (AF_WritingSystem_DoneMetricsFunc) NULL, 2278 2279 (AF_WritingSystem_InitHintsFunc) af_cjk_hints_init, 2280 (AF_WritingSystem_ApplyHintsFunc) af_cjk_hints_apply 2281 ) 2282 2283 2284 #else /* !AF_CONFIG_OPTION_CJK */ 2285 2286 2287 AF_DEFINE_WRITING_SYSTEM_CLASS( 2288 af_cjk_writing_system_class, 2289 2290 AF_WRITING_SYSTEM_CJK, 2291 2292 sizeof ( AF_CJKMetricsRec ), 2293 2294 (AF_WritingSystem_InitMetricsFunc) NULL, 2295 (AF_WritingSystem_ScaleMetricsFunc)NULL, 2296 (AF_WritingSystem_DoneMetricsFunc) NULL, 2297 2298 (AF_WritingSystem_InitHintsFunc) NULL, 2299 (AF_WritingSystem_ApplyHintsFunc) NULL 2300 ) 2301 2302 2303 #endif /* !AF_CONFIG_OPTION_CJK */ 2304 2305 2306 /* END */ 2307
