1 /**************************************************************************** 2 * 3 * aflatin.c 4 * 5 * Auto-fitter hinting routines for latin writing system (body). 6 * 7 * Copyright (C) 2003-2021 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 #include <freetype/ftadvanc.h> 20 #include <freetype/internal/ftdebug.h> 21 22 #include "afglobal.h" 23 #include "aflatin.h" 24 #include "aferrors.h" 25 26 27 /************************************************************************** 28 * 29 * The macro FT_COMPONENT is used in trace mode. It is an implicit 30 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log 31 * messages during execution. 32 */ 33 #undef FT_COMPONENT 34 #define FT_COMPONENT aflatin 35 36 37 /* needed for computation of round vs. flat segments */ 38 #define FLAT_THRESHOLD( x ) ( x / 14 ) 39 40 41 /*************************************************************************/ 42 /*************************************************************************/ 43 /***** *****/ 44 /***** L A T I N G L O B A L M E T R I C S *****/ 45 /***** *****/ 46 /*************************************************************************/ 47 /*************************************************************************/ 48 49 50 /* Find segments and links, compute all stem widths, and initialize */ 51 /* standard width and height for the glyph with given charcode. */ 52 53 FT_LOCAL_DEF( void ) af_latin_metrics_init_widths(AF_LatinMetrics metrics,FT_Face face)54 af_latin_metrics_init_widths( AF_LatinMetrics metrics, 55 FT_Face face ) 56 { 57 /* scan the array of segments in each direction */ 58 AF_GlyphHintsRec hints[1]; 59 60 61 FT_TRACE5(( "\n" )); 62 FT_TRACE5(( "latin standard widths computation (style `%s')\n", 63 af_style_names[metrics->root.style_class->style] )); 64 FT_TRACE5(( "=====================================================\n" )); 65 FT_TRACE5(( "\n" )); 66 67 af_glyph_hints_init( hints, face->memory ); 68 69 metrics->axis[AF_DIMENSION_HORZ].width_count = 0; 70 metrics->axis[AF_DIMENSION_VERT].width_count = 0; 71 72 { 73 FT_Error error; 74 FT_ULong glyph_index; 75 int dim; 76 AF_LatinMetricsRec dummy[1]; 77 AF_Scaler scaler = &dummy->root.scaler; 78 79 AF_StyleClass style_class = metrics->root.style_class; 80 AF_ScriptClass script_class = af_script_classes[style_class->script]; 81 82 /* If HarfBuzz is not available, we need a pointer to a single */ 83 /* unsigned long value. */ 84 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ 85 void* shaper_buf; 86 #else 87 FT_ULong shaper_buf_; 88 void* shaper_buf = &shaper_buf_; 89 #endif 90 91 const char* p; 92 93 #ifdef FT_DEBUG_LEVEL_TRACE 94 FT_ULong ch = 0; 95 #endif 96 97 98 p = script_class->standard_charstring; 99 100 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ 101 shaper_buf = af_shaper_buf_create( face ); 102 #endif 103 /* 104 * We check a list of standard characters to catch features like 105 * `c2sc' (small caps from caps) that don't contain lowercase letters 106 * by definition, or other features that mainly operate on numerals. 107 * The first match wins. 108 */ 109 110 glyph_index = 0; 111 while ( *p ) 112 { 113 unsigned int num_idx; 114 115 #ifdef FT_DEBUG_LEVEL_TRACE 116 const char* p_old; 117 #endif 118 119 120 while ( *p == ' ' ) 121 p++; 122 123 #ifdef FT_DEBUG_LEVEL_TRACE 124 p_old = p; 125 GET_UTF8_CHAR( ch, p_old ); 126 #endif 127 128 /* reject input that maps to more than a single glyph */ 129 p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx ); 130 if ( num_idx > 1 ) 131 continue; 132 133 /* otherwise exit loop if we have a result */ 134 glyph_index = af_shaper_get_elem( &metrics->root, 135 shaper_buf, 136 0, 137 NULL, 138 NULL ); 139 if ( glyph_index ) 140 break; 141 } 142 143 af_shaper_buf_destroy( face, shaper_buf ); 144 145 if ( !glyph_index ) 146 { 147 FT_TRACE5(( "standard character missing;" 148 " using fallback stem widths\n" )); 149 goto Exit; 150 } 151 152 FT_TRACE5(( "standard character: U+%04lX (glyph index %ld)\n", 153 ch, glyph_index )); 154 155 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); 156 if ( error || face->glyph->outline.n_points <= 0 ) 157 goto Exit; 158 159 FT_ZERO( dummy ); 160 161 dummy->units_per_em = metrics->units_per_em; 162 163 scaler->x_scale = 0x10000L; 164 scaler->y_scale = 0x10000L; 165 scaler->x_delta = 0; 166 scaler->y_delta = 0; 167 168 scaler->face = face; 169 scaler->render_mode = FT_RENDER_MODE_NORMAL; 170 scaler->flags = 0; 171 172 af_glyph_hints_rescale( hints, (AF_StyleMetrics)dummy ); 173 174 error = af_glyph_hints_reload( hints, &face->glyph->outline ); 175 if ( error ) 176 goto Exit; 177 178 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 179 { 180 AF_LatinAxis axis = &metrics->axis[dim]; 181 AF_AxisHints axhints = &hints->axis[dim]; 182 AF_Segment seg, limit, link; 183 FT_UInt num_widths = 0; 184 185 186 error = af_latin_hints_compute_segments( hints, 187 (AF_Dimension)dim ); 188 if ( error ) 189 goto Exit; 190 191 /* 192 * We assume that the glyphs selected for the stem width 193 * computation are `featureless' enough so that the linking 194 * algorithm works fine without adjustments of its scoring 195 * function. 196 */ 197 af_latin_hints_link_segments( hints, 198 0, 199 NULL, 200 (AF_Dimension)dim ); 201 202 seg = axhints->segments; 203 limit = seg + axhints->num_segments; 204 205 for ( ; seg < limit; seg++ ) 206 { 207 link = seg->link; 208 209 /* we only consider stem segments there! */ 210 if ( link && link->link == seg && link > seg ) 211 { 212 FT_Pos dist; 213 214 215 dist = seg->pos - link->pos; 216 if ( dist < 0 ) 217 dist = -dist; 218 219 if ( num_widths < AF_LATIN_MAX_WIDTHS ) 220 axis->widths[num_widths++].org = dist; 221 } 222 } 223 224 /* this also replaces multiple almost identical stem widths */ 225 /* with a single one (the value 100 is heuristic) */ 226 af_sort_and_quantize_widths( &num_widths, axis->widths, 227 dummy->units_per_em / 100 ); 228 axis->width_count = num_widths; 229 } 230 231 Exit: 232 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 233 { 234 AF_LatinAxis axis = &metrics->axis[dim]; 235 FT_Pos stdw; 236 237 238 stdw = ( axis->width_count > 0 ) ? axis->widths[0].org 239 : AF_LATIN_CONSTANT( metrics, 50 ); 240 241 /* let's try 20% of the smallest width */ 242 axis->edge_distance_threshold = stdw / 5; 243 axis->standard_width = stdw; 244 axis->extra_light = 0; 245 246 #ifdef FT_DEBUG_LEVEL_TRACE 247 { 248 FT_UInt i; 249 250 251 FT_TRACE5(( "%s widths:\n", 252 dim == AF_DIMENSION_VERT ? "horizontal" 253 : "vertical" )); 254 255 FT_TRACE5(( " %ld (standard)", axis->standard_width )); 256 for ( i = 1; i < axis->width_count; i++ ) 257 FT_TRACE5(( " %ld", axis->widths[i].org )); 258 259 FT_TRACE5(( "\n" )); 260 } 261 #endif 262 } 263 } 264 265 FT_TRACE5(( "\n" )); 266 267 af_glyph_hints_done( hints ); 268 } 269 270 271 static void af_latin_sort_blue(FT_UInt count,AF_LatinBlue * table)272 af_latin_sort_blue( FT_UInt count, 273 AF_LatinBlue* table ) 274 { 275 FT_UInt i, j; 276 AF_LatinBlue swap; 277 278 279 /* we sort from bottom to top */ 280 for ( i = 1; i < count; i++ ) 281 { 282 for ( j = i; j > 0; j-- ) 283 { 284 FT_Pos a, b; 285 286 287 if ( table[j - 1]->flags & ( AF_LATIN_BLUE_TOP | 288 AF_LATIN_BLUE_SUB_TOP ) ) 289 a = table[j - 1]->ref.org; 290 else 291 a = table[j - 1]->shoot.org; 292 293 if ( table[j]->flags & ( AF_LATIN_BLUE_TOP | 294 AF_LATIN_BLUE_SUB_TOP ) ) 295 b = table[j]->ref.org; 296 else 297 b = table[j]->shoot.org; 298 299 if ( b >= a ) 300 break; 301 302 swap = table[j]; 303 table[j] = table[j - 1]; 304 table[j - 1] = swap; 305 } 306 } 307 } 308 309 310 /* Find all blue zones. Flat segments give the reference points, */ 311 /* round segments the overshoot positions. */ 312 313 static int af_latin_metrics_init_blues(AF_LatinMetrics metrics,FT_Face face)314 af_latin_metrics_init_blues( AF_LatinMetrics metrics, 315 FT_Face face ) 316 { 317 FT_Pos flats [AF_BLUE_STRING_MAX_LEN]; 318 FT_Pos rounds[AF_BLUE_STRING_MAX_LEN]; 319 320 FT_UInt num_flats; 321 FT_UInt num_rounds; 322 323 AF_LatinBlue blue; 324 FT_Error error; 325 AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT]; 326 FT_Outline outline; 327 328 AF_StyleClass sc = metrics->root.style_class; 329 330 AF_Blue_Stringset bss = sc->blue_stringset; 331 const AF_Blue_StringRec* bs = &af_blue_stringsets[bss]; 332 333 FT_Pos flat_threshold = FLAT_THRESHOLD( metrics->units_per_em ); 334 335 /* If HarfBuzz is not available, we need a pointer to a single */ 336 /* unsigned long value. */ 337 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ 338 void* shaper_buf; 339 #else 340 FT_ULong shaper_buf_; 341 void* shaper_buf = &shaper_buf_; 342 #endif 343 344 345 /* we walk over the blue character strings as specified in the */ 346 /* style's entry in the `af_blue_stringset' array */ 347 348 FT_TRACE5(( "latin blue zones computation\n" )); 349 FT_TRACE5(( "============================\n" )); 350 FT_TRACE5(( "\n" )); 351 352 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ 353 shaper_buf = af_shaper_buf_create( face ); 354 #endif 355 356 for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ ) 357 { 358 const char* p = &af_blue_strings[bs->string]; 359 FT_Pos* blue_ref; 360 FT_Pos* blue_shoot; 361 FT_Pos ascender; 362 FT_Pos descender; 363 364 365 #ifdef FT_DEBUG_LEVEL_TRACE 366 { 367 FT_Bool have_flag = 0; 368 369 370 FT_TRACE5(( "blue zone %d", axis->blue_count )); 371 372 if ( bs->properties ) 373 { 374 FT_TRACE5(( " (" )); 375 376 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 377 { 378 FT_TRACE5(( "top" )); 379 have_flag = 1; 380 } 381 else if ( AF_LATIN_IS_SUB_TOP_BLUE( bs ) ) 382 { 383 FT_TRACE5(( "sub top" )); 384 have_flag = 1; 385 } 386 387 if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) 388 { 389 if ( have_flag ) 390 FT_TRACE5(( ", " )); 391 FT_TRACE5(( "neutral" )); 392 have_flag = 1; 393 } 394 395 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) 396 { 397 if ( have_flag ) 398 FT_TRACE5(( ", " )); 399 FT_TRACE5(( "small top" )); 400 have_flag = 1; 401 } 402 403 if ( AF_LATIN_IS_LONG_BLUE( bs ) ) 404 { 405 if ( have_flag ) 406 FT_TRACE5(( ", " )); 407 FT_TRACE5(( "long" )); 408 } 409 410 FT_TRACE5(( ")" )); 411 } 412 413 FT_TRACE5(( ":\n" )); 414 } 415 #endif /* FT_DEBUG_LEVEL_TRACE */ 416 417 num_flats = 0; 418 num_rounds = 0; 419 ascender = 0; 420 descender = 0; 421 422 while ( *p ) 423 { 424 FT_ULong glyph_index; 425 FT_Long y_offset; 426 FT_Int best_point, best_contour_first, best_contour_last; 427 FT_Vector* points; 428 429 FT_Pos best_y_extremum; /* same as points.y */ 430 FT_Bool best_round = 0; 431 432 unsigned int i, num_idx; 433 434 #ifdef FT_DEBUG_LEVEL_TRACE 435 const char* p_old; 436 FT_ULong ch; 437 #endif 438 439 440 while ( *p == ' ' ) 441 p++; 442 443 #ifdef FT_DEBUG_LEVEL_TRACE 444 p_old = p; 445 GET_UTF8_CHAR( ch, p_old ); 446 #endif 447 448 p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx ); 449 450 if ( !num_idx ) 451 { 452 FT_TRACE5(( " U+%04lX unavailable\n", ch )); 453 continue; 454 } 455 456 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 457 best_y_extremum = FT_INT_MIN; 458 else 459 best_y_extremum = FT_INT_MAX; 460 461 /* iterate over all glyph elements of the character cluster */ 462 /* and get the data of the `biggest' one */ 463 for ( i = 0; i < num_idx; i++ ) 464 { 465 FT_Pos best_y; 466 FT_Bool round = 0; 467 468 469 /* load the character in the face -- skip unknown or empty ones */ 470 glyph_index = af_shaper_get_elem( &metrics->root, 471 shaper_buf, 472 i, 473 NULL, 474 &y_offset ); 475 if ( glyph_index == 0 ) 476 { 477 FT_TRACE5(( " U+%04lX unavailable\n", ch )); 478 continue; 479 } 480 481 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); 482 outline = face->glyph->outline; 483 /* reject glyphs that don't produce any rendering */ 484 if ( error || outline.n_points <= 2 ) 485 { 486 #ifdef FT_DEBUG_LEVEL_TRACE 487 if ( num_idx == 1 ) 488 FT_TRACE5(( " U+%04lX contains no (usable) outlines\n", ch )); 489 else 490 FT_TRACE5(( " component %d of cluster starting with U+%04lX" 491 " contains no (usable) outlines\n", i, ch )); 492 #endif 493 continue; 494 } 495 496 /* now compute min or max point indices and coordinates */ 497 points = outline.points; 498 best_point = -1; 499 best_y = 0; /* make compiler happy */ 500 best_contour_first = 0; /* ditto */ 501 best_contour_last = 0; /* ditto */ 502 503 { 504 FT_Int nn; 505 FT_Int first = 0; 506 FT_Int last = -1; 507 508 509 for ( nn = 0; nn < outline.n_contours; first = last + 1, nn++ ) 510 { 511 FT_Int old_best_point = best_point; 512 FT_Int pp; 513 514 515 last = outline.contours[nn]; 516 517 /* Avoid single-point contours since they are never */ 518 /* rasterized. In some fonts, they correspond to mark */ 519 /* attachment points that are way outside of the glyph's */ 520 /* real outline. */ 521 if ( last <= first ) 522 continue; 523 524 if ( AF_LATIN_IS_TOP_BLUE( bs ) || 525 AF_LATIN_IS_SUB_TOP_BLUE( bs ) ) 526 { 527 for ( pp = first; pp <= last; pp++ ) 528 { 529 if ( best_point < 0 || points[pp].y > best_y ) 530 { 531 best_point = pp; 532 best_y = points[pp].y; 533 ascender = FT_MAX( ascender, best_y + y_offset ); 534 } 535 else 536 descender = FT_MIN( descender, points[pp].y + y_offset ); 537 } 538 } 539 else 540 { 541 for ( pp = first; pp <= last; pp++ ) 542 { 543 if ( best_point < 0 || points[pp].y < best_y ) 544 { 545 best_point = pp; 546 best_y = points[pp].y; 547 descender = FT_MIN( descender, best_y + y_offset ); 548 } 549 else 550 ascender = FT_MAX( ascender, points[pp].y + y_offset ); 551 } 552 } 553 554 if ( best_point != old_best_point ) 555 { 556 best_contour_first = first; 557 best_contour_last = last; 558 } 559 } 560 } 561 562 /* now check whether the point belongs to a straight or round */ 563 /* segment; we first need to find in which contour the extremum */ 564 /* lies, then inspect its previous and next points */ 565 if ( best_point >= 0 ) 566 { 567 FT_Pos best_x = points[best_point].x; 568 FT_Int prev, next; 569 FT_Int best_segment_first, best_segment_last; 570 FT_Int best_on_point_first, best_on_point_last; 571 FT_Pos dist; 572 573 574 best_segment_first = best_point; 575 best_segment_last = best_point; 576 577 if ( FT_CURVE_TAG( outline.tags[best_point] ) == FT_CURVE_TAG_ON ) 578 { 579 best_on_point_first = best_point; 580 best_on_point_last = best_point; 581 } 582 else 583 { 584 best_on_point_first = -1; 585 best_on_point_last = -1; 586 } 587 588 /* look for the previous and next points on the contour */ 589 /* that are not on the same Y coordinate, then threshold */ 590 /* the `closeness'... */ 591 prev = best_point; 592 next = prev; 593 594 do 595 { 596 if ( prev > best_contour_first ) 597 prev--; 598 else 599 prev = best_contour_last; 600 601 dist = FT_ABS( points[prev].y - best_y ); 602 /* accept a small distance or a small angle (both values are */ 603 /* heuristic; value 20 corresponds to approx. 2.9 degrees) */ 604 if ( dist > 5 ) 605 if ( FT_ABS( points[prev].x - best_x ) <= 20 * dist ) 606 break; 607 608 best_segment_first = prev; 609 610 if ( FT_CURVE_TAG( outline.tags[prev] ) == FT_CURVE_TAG_ON ) 611 { 612 best_on_point_first = prev; 613 if ( best_on_point_last < 0 ) 614 best_on_point_last = prev; 615 } 616 617 } while ( prev != best_point ); 618 619 do 620 { 621 if ( next < best_contour_last ) 622 next++; 623 else 624 next = best_contour_first; 625 626 dist = FT_ABS( points[next].y - best_y ); 627 if ( dist > 5 ) 628 if ( FT_ABS( points[next].x - best_x ) <= 20 * dist ) 629 break; 630 631 best_segment_last = next; 632 633 if ( FT_CURVE_TAG( outline.tags[next] ) == FT_CURVE_TAG_ON ) 634 { 635 best_on_point_last = next; 636 if ( best_on_point_first < 0 ) 637 best_on_point_first = next; 638 } 639 640 } while ( next != best_point ); 641 642 if ( AF_LATIN_IS_LONG_BLUE( bs ) ) 643 { 644 /* If this flag is set, we have an additional constraint to */ 645 /* get the blue zone distance: Find a segment of the topmost */ 646 /* (or bottommost) contour that is longer than a heuristic */ 647 /* threshold. This ensures that small bumps in the outline */ 648 /* are ignored (for example, the `vertical serifs' found in */ 649 /* many Hebrew glyph designs). */ 650 651 /* If this segment is long enough, we are done. Otherwise, */ 652 /* search the segment next to the extremum that is long */ 653 /* enough, has the same direction, and a not too large */ 654 /* vertical distance from the extremum. Note that the */ 655 /* algorithm doesn't check whether the found segment is */ 656 /* actually the one (vertically) nearest to the extremum. */ 657 658 /* heuristic threshold value */ 659 FT_Pos length_threshold = metrics->units_per_em / 25; 660 661 662 dist = FT_ABS( points[best_segment_last].x - 663 points[best_segment_first].x ); 664 665 if ( dist < length_threshold && 666 best_segment_last - best_segment_first + 2 <= 667 best_contour_last - best_contour_first ) 668 { 669 /* heuristic threshold value */ 670 FT_Pos height_threshold = metrics->units_per_em / 4; 671 672 FT_Int first; 673 FT_Int last; 674 FT_Bool hit; 675 676 /* we intentionally declare these two variables */ 677 /* outside of the loop since various compilers emit */ 678 /* incorrect warning messages otherwise, talking about */ 679 /* `possibly uninitialized variables' */ 680 FT_Int p_first = 0; /* make compiler happy */ 681 FT_Int p_last = 0; 682 683 FT_Bool left2right; 684 685 686 /* compute direction */ 687 prev = best_point; 688 689 do 690 { 691 if ( prev > best_contour_first ) 692 prev--; 693 else 694 prev = best_contour_last; 695 696 if ( points[prev].x != best_x ) 697 break; 698 699 } while ( prev != best_point ); 700 701 /* skip glyph for the degenerate case */ 702 if ( prev == best_point ) 703 continue; 704 705 left2right = FT_BOOL( points[prev].x < points[best_point].x ); 706 707 first = best_segment_last; 708 last = first; 709 hit = 0; 710 711 do 712 { 713 FT_Bool l2r; 714 FT_Pos d; 715 716 717 if ( !hit ) 718 { 719 /* no hit; adjust first point */ 720 first = last; 721 722 /* also adjust first and last on point */ 723 if ( FT_CURVE_TAG( outline.tags[first] ) == 724 FT_CURVE_TAG_ON ) 725 { 726 p_first = first; 727 p_last = first; 728 } 729 else 730 { 731 p_first = -1; 732 p_last = -1; 733 } 734 735 hit = 1; 736 } 737 738 if ( last < best_contour_last ) 739 last++; 740 else 741 last = best_contour_first; 742 743 if ( FT_ABS( best_y - points[first].y ) > height_threshold ) 744 { 745 /* vertical distance too large */ 746 hit = 0; 747 continue; 748 } 749 750 /* same test as above */ 751 dist = FT_ABS( points[last].y - points[first].y ); 752 if ( dist > 5 ) 753 if ( FT_ABS( points[last].x - points[first].x ) <= 754 20 * dist ) 755 { 756 hit = 0; 757 continue; 758 } 759 760 if ( FT_CURVE_TAG( outline.tags[last] ) == FT_CURVE_TAG_ON ) 761 { 762 p_last = last; 763 if ( p_first < 0 ) 764 p_first = last; 765 } 766 767 l2r = FT_BOOL( points[first].x < points[last].x ); 768 d = FT_ABS( points[last].x - points[first].x ); 769 770 if ( l2r == left2right && 771 d >= length_threshold ) 772 { 773 /* all constraints are met; update segment after */ 774 /* finding its end */ 775 do 776 { 777 if ( last < best_contour_last ) 778 last++; 779 else 780 last = best_contour_first; 781 782 d = FT_ABS( points[last].y - points[first].y ); 783 if ( d > 5 ) 784 if ( FT_ABS( points[next].x - points[first].x ) <= 785 20 * dist ) 786 { 787 if ( last > best_contour_first ) 788 last--; 789 else 790 last = best_contour_last; 791 break; 792 } 793 794 p_last = last; 795 796 if ( FT_CURVE_TAG( outline.tags[last] ) == 797 FT_CURVE_TAG_ON ) 798 { 799 p_last = last; 800 if ( p_first < 0 ) 801 p_first = last; 802 } 803 804 } while ( last != best_segment_first ); 805 806 best_y = points[first].y; 807 808 best_segment_first = first; 809 best_segment_last = last; 810 811 best_on_point_first = p_first; 812 best_on_point_last = p_last; 813 814 break; 815 } 816 817 } while ( last != best_segment_first ); 818 } 819 } 820 821 /* for computing blue zones, we add the y offset as returned */ 822 /* by the currently used OpenType feature -- for example, */ 823 /* superscript glyphs might be identical to subscript glyphs */ 824 /* with a vertical shift */ 825 best_y += y_offset; 826 827 #ifdef FT_DEBUG_LEVEL_TRACE 828 if ( num_idx == 1 ) 829 FT_TRACE5(( " U+%04lX: best_y = %5ld", ch, best_y )); 830 else 831 FT_TRACE5(( " component %d of cluster starting with U+%04lX:" 832 " best_y = %5ld", i, ch, best_y )); 833 #endif 834 835 /* now set the `round' flag depending on the segment's kind: */ 836 /* */ 837 /* - if the horizontal distance between the first and last */ 838 /* `on' point is larger than a heuristic threshold */ 839 /* we have a flat segment */ 840 /* - if either the first or the last point of the segment is */ 841 /* an `off' point, the segment is round, otherwise it is */ 842 /* flat */ 843 if ( best_on_point_first >= 0 && 844 best_on_point_last >= 0 && 845 ( FT_ABS( points[best_on_point_last].x - 846 points[best_on_point_first].x ) ) > 847 flat_threshold ) 848 round = 0; 849 else 850 round = FT_BOOL( 851 FT_CURVE_TAG( outline.tags[best_segment_first] ) != 852 FT_CURVE_TAG_ON || 853 FT_CURVE_TAG( outline.tags[best_segment_last] ) != 854 FT_CURVE_TAG_ON ); 855 856 if ( round && AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) 857 { 858 /* only use flat segments for a neutral blue zone */ 859 FT_TRACE5(( " (round, skipped)\n" )); 860 continue; 861 } 862 863 FT_TRACE5(( " (%s)\n", round ? "round" : "flat" )); 864 } 865 866 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 867 { 868 if ( best_y > best_y_extremum ) 869 { 870 best_y_extremum = best_y; 871 best_round = round; 872 } 873 } 874 else 875 { 876 if ( best_y < best_y_extremum ) 877 { 878 best_y_extremum = best_y; 879 best_round = round; 880 } 881 } 882 883 } /* end for loop */ 884 885 if ( !( best_y_extremum == FT_INT_MIN || 886 best_y_extremum == FT_INT_MAX ) ) 887 { 888 if ( best_round ) 889 rounds[num_rounds++] = best_y_extremum; 890 else 891 flats[num_flats++] = best_y_extremum; 892 } 893 894 } /* end while loop */ 895 896 if ( num_flats == 0 && num_rounds == 0 ) 897 { 898 /* 899 * we couldn't find a single glyph to compute this blue zone, 900 * we will simply ignore it then 901 */ 902 FT_TRACE5(( " empty\n" )); 903 continue; 904 } 905 906 /* we have computed the contents of the `rounds' and `flats' tables, */ 907 /* now determine the reference and overshoot position of the blue -- */ 908 /* we simply take the median value after a simple sort */ 909 af_sort_pos( num_rounds, rounds ); 910 af_sort_pos( num_flats, flats ); 911 912 blue = &axis->blues[axis->blue_count]; 913 blue_ref = &blue->ref.org; 914 blue_shoot = &blue->shoot.org; 915 916 axis->blue_count++; 917 918 if ( num_flats == 0 ) 919 { 920 *blue_ref = 921 *blue_shoot = rounds[num_rounds / 2]; 922 } 923 else if ( num_rounds == 0 ) 924 { 925 *blue_ref = 926 *blue_shoot = flats[num_flats / 2]; 927 } 928 else 929 { 930 *blue_ref = flats [num_flats / 2]; 931 *blue_shoot = rounds[num_rounds / 2]; 932 } 933 934 /* there are sometimes problems: if the overshoot position of top */ 935 /* zones is under its reference position, or the opposite for bottom */ 936 /* zones. We must thus check everything there and correct the errors */ 937 if ( *blue_shoot != *blue_ref ) 938 { 939 FT_Pos ref = *blue_ref; 940 FT_Pos shoot = *blue_shoot; 941 FT_Bool over_ref = FT_BOOL( shoot > ref ); 942 943 944 if ( ( AF_LATIN_IS_TOP_BLUE( bs ) || 945 AF_LATIN_IS_SUB_TOP_BLUE( bs) ) ^ over_ref ) 946 { 947 *blue_ref = 948 *blue_shoot = ( shoot + ref ) / 2; 949 950 FT_TRACE5(( " [overshoot smaller than reference," 951 " taking mean value]\n" )); 952 } 953 } 954 955 blue->ascender = ascender; 956 blue->descender = descender; 957 958 blue->flags = 0; 959 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 960 blue->flags |= AF_LATIN_BLUE_TOP; 961 if ( AF_LATIN_IS_SUB_TOP_BLUE( bs ) ) 962 blue->flags |= AF_LATIN_BLUE_SUB_TOP; 963 if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) 964 blue->flags |= AF_LATIN_BLUE_NEUTRAL; 965 966 /* 967 * The following flag is used later to adjust the y and x scales 968 * in order to optimize the pixel grid alignment of the top of small 969 * letters. 970 */ 971 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) 972 blue->flags |= AF_LATIN_BLUE_ADJUSTMENT; 973 974 FT_TRACE5(( " -> reference = %ld\n", *blue_ref )); 975 FT_TRACE5(( " overshoot = %ld\n", *blue_shoot )); 976 977 } /* end for loop */ 978 979 af_shaper_buf_destroy( face, shaper_buf ); 980 981 if ( axis->blue_count ) 982 { 983 /* we finally check whether blue zones are ordered; */ 984 /* `ref' and `shoot' values of two blue zones must not overlap */ 985 986 FT_UInt i; 987 AF_LatinBlue blue_sorted[AF_BLUE_STRINGSET_MAX_LEN + 2]; 988 989 990 for ( i = 0; i < axis->blue_count; i++ ) 991 blue_sorted[i] = &axis->blues[i]; 992 993 /* sort bottoms of blue zones... */ 994 af_latin_sort_blue( axis->blue_count, blue_sorted ); 995 996 /* ...and adjust top values if necessary */ 997 for ( i = 0; i < axis->blue_count - 1; i++ ) 998 { 999 FT_Pos* a; 1000 FT_Pos* b; 1001 1002 #ifdef FT_DEBUG_LEVEL_TRACE 1003 FT_Bool a_is_top = 0; 1004 #endif 1005 1006 1007 if ( blue_sorted[i]->flags & ( AF_LATIN_BLUE_TOP | 1008 AF_LATIN_BLUE_SUB_TOP ) ) 1009 { 1010 a = &blue_sorted[i]->shoot.org; 1011 #ifdef FT_DEBUG_LEVEL_TRACE 1012 a_is_top = 1; 1013 #endif 1014 } 1015 else 1016 a = &blue_sorted[i]->ref.org; 1017 1018 if ( blue_sorted[i + 1]->flags & ( AF_LATIN_BLUE_TOP | 1019 AF_LATIN_BLUE_SUB_TOP ) ) 1020 b = &blue_sorted[i + 1]->shoot.org; 1021 else 1022 b = &blue_sorted[i + 1]->ref.org; 1023 1024 if ( *a > *b ) 1025 { 1026 *a = *b; 1027 FT_TRACE5(( "blue zone overlap:" 1028 " adjusting %s %ld to %ld\n", 1029 a_is_top ? "overshoot" : "reference", 1030 blue_sorted[i] - axis->blues, 1031 *a )); 1032 } 1033 } 1034 1035 FT_TRACE5(( "\n" )); 1036 1037 return 0; 1038 } 1039 else 1040 { 1041 /* disable hinting for the current style if there are no blue zones */ 1042 1043 AF_FaceGlobals globals = metrics->root.globals; 1044 FT_UShort* gstyles = globals->glyph_styles; 1045 1046 FT_Long i; 1047 1048 1049 FT_TRACE5(( "no blue zones found:" 1050 " hinting disabled for this style\n" )); 1051 1052 for ( i = 0; i < globals->glyph_count; i++ ) 1053 { 1054 if ( ( gstyles[i] & AF_STYLE_MASK ) == sc->style ) 1055 gstyles[i] = AF_STYLE_NONE_DFLT; 1056 } 1057 1058 FT_TRACE5(( "\n" )); 1059 1060 return 1; 1061 } 1062 } 1063 1064 1065 /* Check whether all ASCII digits have the same advance width. */ 1066 1067 FT_LOCAL_DEF( void ) af_latin_metrics_check_digits(AF_LatinMetrics metrics,FT_Face face)1068 af_latin_metrics_check_digits( AF_LatinMetrics metrics, 1069 FT_Face face ) 1070 { 1071 FT_Bool started = 0, same_width = 1; 1072 FT_Fixed advance = 0, old_advance = 0; 1073 1074 /* If HarfBuzz is not available, we need a pointer to a single */ 1075 /* unsigned long value. */ 1076 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ 1077 void* shaper_buf; 1078 #else 1079 FT_ULong shaper_buf_; 1080 void* shaper_buf = &shaper_buf_; 1081 #endif 1082 1083 /* in all supported charmaps, digits have character codes 0x30-0x39 */ 1084 const char digits[] = "0 1 2 3 4 5 6 7 8 9"; 1085 const char* p; 1086 1087 1088 p = digits; 1089 1090 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ 1091 shaper_buf = af_shaper_buf_create( face ); 1092 #endif 1093 1094 while ( *p ) 1095 { 1096 FT_ULong glyph_index; 1097 unsigned int num_idx; 1098 1099 1100 /* reject input that maps to more than a single glyph */ 1101 p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx ); 1102 if ( num_idx > 1 ) 1103 continue; 1104 1105 glyph_index = af_shaper_get_elem( &metrics->root, 1106 shaper_buf, 1107 0, 1108 &advance, 1109 NULL ); 1110 if ( !glyph_index ) 1111 continue; 1112 1113 if ( started ) 1114 { 1115 if ( advance != old_advance ) 1116 { 1117 same_width = 0; 1118 break; 1119 } 1120 } 1121 else 1122 { 1123 old_advance = advance; 1124 started = 1; 1125 } 1126 } 1127 1128 af_shaper_buf_destroy( face, shaper_buf ); 1129 1130 metrics->root.digits_have_same_width = same_width; 1131 } 1132 1133 1134 /* Initialize global metrics. */ 1135 1136 FT_LOCAL_DEF( FT_Error ) af_latin_metrics_init(AF_LatinMetrics metrics,FT_Face face)1137 af_latin_metrics_init( AF_LatinMetrics metrics, 1138 FT_Face face ) 1139 { 1140 FT_Error error = FT_Err_Ok; 1141 1142 FT_CharMap oldmap = face->charmap; 1143 1144 1145 metrics->units_per_em = face->units_per_EM; 1146 1147 if ( !FT_Select_Charmap( face, FT_ENCODING_UNICODE ) ) 1148 { 1149 af_latin_metrics_init_widths( metrics, face ); 1150 if ( af_latin_metrics_init_blues( metrics, face ) ) 1151 { 1152 /* use internal error code to indicate missing blue zones */ 1153 error = -1; 1154 goto Exit; 1155 } 1156 af_latin_metrics_check_digits( metrics, face ); 1157 } 1158 1159 Exit: 1160 FT_Set_Charmap( face, oldmap ); 1161 return error; 1162 } 1163 1164 1165 /* Adjust scaling value, then scale and shift widths */ 1166 /* and blue zones (if applicable) for given dimension. */ 1167 1168 static void af_latin_metrics_scale_dim(AF_LatinMetrics metrics,AF_Scaler scaler,AF_Dimension dim)1169 af_latin_metrics_scale_dim( AF_LatinMetrics metrics, 1170 AF_Scaler scaler, 1171 AF_Dimension dim ) 1172 { 1173 FT_Fixed scale; 1174 FT_Pos delta; 1175 AF_LatinAxis axis; 1176 FT_UInt nn; 1177 1178 1179 if ( dim == AF_DIMENSION_HORZ ) 1180 { 1181 scale = scaler->x_scale; 1182 delta = scaler->x_delta; 1183 } 1184 else 1185 { 1186 scale = scaler->y_scale; 1187 delta = scaler->y_delta; 1188 } 1189 1190 axis = &metrics->axis[dim]; 1191 1192 if ( axis->org_scale == scale && axis->org_delta == delta ) 1193 return; 1194 1195 axis->org_scale = scale; 1196 axis->org_delta = delta; 1197 1198 /* 1199 * correct X and Y scale to optimize the alignment of the top of small 1200 * letters to the pixel grid 1201 */ 1202 { 1203 AF_LatinAxis Axis = &metrics->axis[AF_DIMENSION_VERT]; 1204 AF_LatinBlue blue = NULL; 1205 1206 1207 for ( nn = 0; nn < Axis->blue_count; nn++ ) 1208 { 1209 if ( Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT ) 1210 { 1211 blue = &Axis->blues[nn]; 1212 break; 1213 } 1214 } 1215 1216 if ( blue ) 1217 { 1218 FT_Pos scaled; 1219 FT_Pos threshold; 1220 FT_Pos fitted; 1221 FT_UInt limit; 1222 FT_UInt ppem; 1223 1224 1225 scaled = FT_MulFix( blue->shoot.org, scale ); 1226 ppem = metrics->root.scaler.face->size->metrics.x_ppem; 1227 limit = metrics->root.globals->increase_x_height; 1228 threshold = 40; 1229 1230 /* if the `increase-x-height' property is active, */ 1231 /* we round up much more often */ 1232 if ( limit && 1233 ppem <= limit && 1234 ppem >= AF_PROP_INCREASE_X_HEIGHT_MIN ) 1235 threshold = 52; 1236 1237 fitted = ( scaled + threshold ) & ~63; 1238 1239 if ( scaled != fitted ) 1240 { 1241 #if 0 1242 if ( dim == AF_DIMENSION_HORZ ) 1243 { 1244 if ( fitted < scaled ) 1245 scale -= scale / 50; /* scale *= 0.98 */ 1246 } 1247 else 1248 #endif 1249 if ( dim == AF_DIMENSION_VERT ) 1250 { 1251 FT_Pos max_height; 1252 FT_Pos dist; 1253 FT_Fixed new_scale; 1254 1255 1256 new_scale = FT_MulDiv( scale, fitted, scaled ); 1257 1258 /* the scaling should not change the result by more than two pixels */ 1259 max_height = metrics->units_per_em; 1260 1261 for ( nn = 0; nn < Axis->blue_count; nn++ ) 1262 { 1263 max_height = FT_MAX( max_height, Axis->blues[nn].ascender ); 1264 max_height = FT_MAX( max_height, -Axis->blues[nn].descender ); 1265 } 1266 1267 dist = FT_ABS( FT_MulFix( max_height, new_scale - scale ) ); 1268 dist &= ~127; 1269 1270 if ( dist == 0 ) 1271 { 1272 FT_TRACE5(( "af_latin_metrics_scale_dim:" 1273 " x height alignment (style `%s'):\n", 1274 af_style_names[metrics->root.style_class->style] )); 1275 FT_TRACE5(( " " 1276 " vertical scaling changed" 1277 " from %.5f to %.5f (by %ld%%)\n", 1278 scale / 65536.0, 1279 new_scale / 65536.0, 1280 ( fitted - scaled ) * 100 / scaled )); 1281 FT_TRACE5(( "\n" )); 1282 1283 scale = new_scale; 1284 } 1285 #ifdef FT_DEBUG_LEVEL_TRACE 1286 else 1287 { 1288 FT_TRACE5(( "af_latin_metrics_scale_dim:" 1289 " x height alignment (style `%s'):\n", 1290 af_style_names[metrics->root.style_class->style] )); 1291 FT_TRACE5(( " " 1292 " excessive vertical scaling abandoned\n" )); 1293 FT_TRACE5(( "\n" )); 1294 } 1295 #endif 1296 } 1297 } 1298 } 1299 } 1300 1301 axis->scale = scale; 1302 axis->delta = delta; 1303 1304 if ( dim == AF_DIMENSION_HORZ ) 1305 { 1306 metrics->root.scaler.x_scale = scale; 1307 metrics->root.scaler.x_delta = delta; 1308 } 1309 else 1310 { 1311 metrics->root.scaler.y_scale = scale; 1312 metrics->root.scaler.y_delta = delta; 1313 } 1314 1315 FT_TRACE5(( "%s widths (style `%s')\n", 1316 dim == AF_DIMENSION_HORZ ? "horizontal" : "vertical", 1317 af_style_names[metrics->root.style_class->style] )); 1318 1319 /* scale the widths */ 1320 for ( nn = 0; nn < axis->width_count; nn++ ) 1321 { 1322 AF_Width width = axis->widths + nn; 1323 1324 1325 width->cur = FT_MulFix( width->org, scale ); 1326 width->fit = width->cur; 1327 1328 FT_TRACE5(( " %ld scaled to %.2f\n", 1329 width->org, 1330 width->cur / 64.0 )); 1331 } 1332 1333 FT_TRACE5(( "\n" )); 1334 1335 /* an extra-light axis corresponds to a standard width that is */ 1336 /* smaller than 5/8 pixels */ 1337 axis->extra_light = 1338 FT_BOOL( FT_MulFix( axis->standard_width, scale ) < 32 + 8 ); 1339 1340 #ifdef FT_DEBUG_LEVEL_TRACE 1341 if ( axis->extra_light ) 1342 { 1343 FT_TRACE5(( "`%s' style is extra light (at current resolution)\n", 1344 af_style_names[metrics->root.style_class->style] )); 1345 FT_TRACE5(( "\n" )); 1346 } 1347 #endif 1348 1349 if ( dim == AF_DIMENSION_VERT ) 1350 { 1351 #ifdef FT_DEBUG_LEVEL_TRACE 1352 if ( axis->blue_count ) 1353 FT_TRACE5(( "blue zones (style `%s')\n", 1354 af_style_names[metrics->root.style_class->style] )); 1355 #endif 1356 1357 /* scale the blue zones */ 1358 for ( nn = 0; nn < axis->blue_count; nn++ ) 1359 { 1360 AF_LatinBlue blue = &axis->blues[nn]; 1361 FT_Pos dist; 1362 1363 1364 blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta; 1365 blue->ref.fit = blue->ref.cur; 1366 blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta; 1367 blue->shoot.fit = blue->shoot.cur; 1368 blue->flags &= ~AF_LATIN_BLUE_ACTIVE; 1369 1370 /* a blue zone is only active if it is less than 3/4 pixels tall */ 1371 dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale ); 1372 if ( dist <= 48 && dist >= -48 ) 1373 { 1374 #if 0 1375 FT_Pos delta1; 1376 #endif 1377 FT_Pos delta2; 1378 1379 1380 /* use discrete values for blue zone widths */ 1381 1382 #if 0 1383 1384 /* generic, original code */ 1385 delta1 = blue->shoot.org - blue->ref.org; 1386 delta2 = delta1; 1387 if ( delta1 < 0 ) 1388 delta2 = -delta2; 1389 1390 delta2 = FT_MulFix( delta2, scale ); 1391 1392 if ( delta2 < 32 ) 1393 delta2 = 0; 1394 else if ( delta2 < 64 ) 1395 delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 ); 1396 else 1397 delta2 = FT_PIX_ROUND( delta2 ); 1398 1399 if ( delta1 < 0 ) 1400 delta2 = -delta2; 1401 1402 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); 1403 blue->shoot.fit = blue->ref.fit + delta2; 1404 1405 #else 1406 1407 /* simplified version due to abs(dist) <= 48 */ 1408 delta2 = dist; 1409 if ( dist < 0 ) 1410 delta2 = -delta2; 1411 1412 if ( delta2 < 32 ) 1413 delta2 = 0; 1414 else if ( delta2 < 48 ) 1415 delta2 = 32; 1416 else 1417 delta2 = 64; 1418 1419 if ( dist < 0 ) 1420 delta2 = -delta2; 1421 1422 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); 1423 blue->shoot.fit = blue->ref.fit - delta2; 1424 1425 #endif 1426 1427 blue->flags |= AF_LATIN_BLUE_ACTIVE; 1428 } 1429 } 1430 1431 /* use sub-top blue zone only if it doesn't overlap with */ 1432 /* another (non-sup-top) blue zone; otherwise, the */ 1433 /* effect would be similar to a neutral blue zone, which */ 1434 /* is not desired here */ 1435 for ( nn = 0; nn < axis->blue_count; nn++ ) 1436 { 1437 AF_LatinBlue blue = &axis->blues[nn]; 1438 FT_UInt i; 1439 1440 1441 if ( !( blue->flags & AF_LATIN_BLUE_SUB_TOP ) ) 1442 continue; 1443 if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) 1444 continue; 1445 1446 for ( i = 0; i < axis->blue_count; i++ ) 1447 { 1448 AF_LatinBlue b = &axis->blues[i]; 1449 1450 1451 if ( b->flags & AF_LATIN_BLUE_SUB_TOP ) 1452 continue; 1453 if ( !( b->flags & AF_LATIN_BLUE_ACTIVE ) ) 1454 continue; 1455 1456 if ( b->ref.fit <= blue->shoot.fit && 1457 b->shoot.fit >= blue->ref.fit ) 1458 { 1459 blue->flags &= ~AF_LATIN_BLUE_ACTIVE; 1460 break; 1461 } 1462 } 1463 } 1464 1465 #ifdef FT_DEBUG_LEVEL_TRACE 1466 for ( nn = 0; nn < axis->blue_count; nn++ ) 1467 { 1468 AF_LatinBlue blue = &axis->blues[nn]; 1469 1470 1471 FT_TRACE5(( " reference %d: %ld scaled to %.2f%s\n", 1472 nn, 1473 blue->ref.org, 1474 blue->ref.fit / 64.0, 1475 ( blue->flags & AF_LATIN_BLUE_ACTIVE ) ? "" 1476 : " (inactive)" )); 1477 FT_TRACE5(( " overshoot %d: %ld scaled to %.2f%s\n", 1478 nn, 1479 blue->shoot.org, 1480 blue->shoot.fit / 64.0, 1481 ( blue->flags & AF_LATIN_BLUE_ACTIVE ) ? "" 1482 : " (inactive)" )); 1483 } 1484 #endif 1485 } 1486 } 1487 1488 1489 /* Scale global values in both directions. */ 1490 1491 FT_LOCAL_DEF( void ) af_latin_metrics_scale(AF_LatinMetrics metrics,AF_Scaler scaler)1492 af_latin_metrics_scale( AF_LatinMetrics metrics, 1493 AF_Scaler scaler ) 1494 { 1495 metrics->root.scaler.render_mode = scaler->render_mode; 1496 metrics->root.scaler.face = scaler->face; 1497 metrics->root.scaler.flags = scaler->flags; 1498 1499 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ ); 1500 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT ); 1501 } 1502 1503 1504 /* Extract standard_width from writing system/script specific */ 1505 /* metrics class. */ 1506 1507 FT_LOCAL_DEF( void ) af_latin_get_standard_widths(AF_LatinMetrics metrics,FT_Pos * stdHW,FT_Pos * stdVW)1508 af_latin_get_standard_widths( AF_LatinMetrics metrics, 1509 FT_Pos* stdHW, 1510 FT_Pos* stdVW ) 1511 { 1512 if ( stdHW ) 1513 *stdHW = metrics->axis[AF_DIMENSION_VERT].standard_width; 1514 1515 if ( stdVW ) 1516 *stdVW = metrics->axis[AF_DIMENSION_HORZ].standard_width; 1517 } 1518 1519 1520 /*************************************************************************/ 1521 /*************************************************************************/ 1522 /***** *****/ 1523 /***** L A T I N G L Y P H A N A L Y S I S *****/ 1524 /***** *****/ 1525 /*************************************************************************/ 1526 /*************************************************************************/ 1527 1528 1529 /* Walk over all contours and compute its segments. */ 1530 1531 FT_LOCAL_DEF( FT_Error ) af_latin_hints_compute_segments(AF_GlyphHints hints,AF_Dimension dim)1532 af_latin_hints_compute_segments( AF_GlyphHints hints, 1533 AF_Dimension dim ) 1534 { 1535 AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics; 1536 AF_AxisHints axis = &hints->axis[dim]; 1537 FT_Memory memory = hints->memory; 1538 FT_Error error = FT_Err_Ok; 1539 AF_Segment segment = NULL; 1540 AF_SegmentRec seg0; 1541 AF_Point* contour = hints->contours; 1542 AF_Point* contour_limit = contour + hints->num_contours; 1543 AF_Direction major_dir, segment_dir; 1544 1545 FT_Pos flat_threshold = FLAT_THRESHOLD( metrics->units_per_em ); 1546 1547 1548 FT_ZERO( &seg0 ); 1549 seg0.score = 32000; 1550 seg0.flags = AF_EDGE_NORMAL; 1551 1552 major_dir = (AF_Direction)FT_ABS( axis->major_dir ); 1553 segment_dir = major_dir; 1554 1555 axis->num_segments = 0; 1556 1557 /* set up (u,v) in each point */ 1558 if ( dim == AF_DIMENSION_HORZ ) 1559 { 1560 AF_Point point = hints->points; 1561 AF_Point limit = point + hints->num_points; 1562 1563 1564 for ( ; point < limit; point++ ) 1565 { 1566 point->u = point->fx; 1567 point->v = point->fy; 1568 } 1569 } 1570 else 1571 { 1572 AF_Point point = hints->points; 1573 AF_Point limit = point + hints->num_points; 1574 1575 1576 for ( ; point < limit; point++ ) 1577 { 1578 point->u = point->fy; 1579 point->v = point->fx; 1580 } 1581 } 1582 1583 /* do each contour separately */ 1584 for ( ; contour < contour_limit; contour++ ) 1585 { 1586 AF_Point point = contour[0]; 1587 AF_Point last = point->prev; 1588 int on_edge = 0; 1589 1590 /* we call values measured along a segment (point->v) */ 1591 /* `coordinates', and values orthogonal to it (point->u) */ 1592 /* `positions' */ 1593 FT_Pos min_pos = 32000; 1594 FT_Pos max_pos = -32000; 1595 FT_Pos min_coord = 32000; 1596 FT_Pos max_coord = -32000; 1597 FT_UShort min_flags = AF_FLAG_NONE; 1598 FT_UShort max_flags = AF_FLAG_NONE; 1599 FT_Pos min_on_coord = 32000; 1600 FT_Pos max_on_coord = -32000; 1601 1602 FT_Bool passed; 1603 1604 AF_Segment prev_segment = NULL; 1605 1606 FT_Pos prev_min_pos = min_pos; 1607 FT_Pos prev_max_pos = max_pos; 1608 FT_Pos prev_min_coord = min_coord; 1609 FT_Pos prev_max_coord = max_coord; 1610 FT_UShort prev_min_flags = min_flags; 1611 FT_UShort prev_max_flags = max_flags; 1612 FT_Pos prev_min_on_coord = min_on_coord; 1613 FT_Pos prev_max_on_coord = max_on_coord; 1614 1615 1616 if ( FT_ABS( last->out_dir ) == major_dir && 1617 FT_ABS( point->out_dir ) == major_dir ) 1618 { 1619 /* we are already on an edge, try to locate its start */ 1620 last = point; 1621 1622 for (;;) 1623 { 1624 point = point->prev; 1625 if ( FT_ABS( point->out_dir ) != major_dir ) 1626 { 1627 point = point->next; 1628 break; 1629 } 1630 if ( point == last ) 1631 break; 1632 } 1633 } 1634 1635 last = point; 1636 passed = 0; 1637 1638 for (;;) 1639 { 1640 FT_Pos u, v; 1641 1642 1643 if ( on_edge ) 1644 { 1645 /* get minimum and maximum position */ 1646 u = point->u; 1647 if ( u < min_pos ) 1648 min_pos = u; 1649 if ( u > max_pos ) 1650 max_pos = u; 1651 1652 /* get minimum and maximum coordinate together with flags */ 1653 v = point->v; 1654 if ( v < min_coord ) 1655 { 1656 min_coord = v; 1657 min_flags = point->flags; 1658 } 1659 if ( v > max_coord ) 1660 { 1661 max_coord = v; 1662 max_flags = point->flags; 1663 } 1664 1665 /* get minimum and maximum coordinate of `on' points */ 1666 if ( !( point->flags & AF_FLAG_CONTROL ) ) 1667 { 1668 v = point->v; 1669 if ( v < min_on_coord ) 1670 min_on_coord = v; 1671 if ( v > max_on_coord ) 1672 max_on_coord = v; 1673 } 1674 1675 if ( point->out_dir != segment_dir || point == last ) 1676 { 1677 /* check whether the new segment's start point is identical to */ 1678 /* the previous segment's end point; for example, this might */ 1679 /* happen for spikes */ 1680 1681 if ( !prev_segment || segment->first != prev_segment->last ) 1682 { 1683 /* points are different: we are just leaving an edge, thus */ 1684 /* record a new segment */ 1685 1686 segment->last = point; 1687 segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); 1688 segment->delta = (FT_Short)( ( max_pos - min_pos ) >> 1 ); 1689 1690 /* a segment is round if either its first or last point */ 1691 /* is a control point, and the length of the on points */ 1692 /* inbetween doesn't exceed a heuristic limit */ 1693 if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL && 1694 ( max_on_coord - min_on_coord ) < flat_threshold ) 1695 segment->flags |= AF_EDGE_ROUND; 1696 1697 segment->min_coord = (FT_Short)min_coord; 1698 segment->max_coord = (FT_Short)max_coord; 1699 segment->height = segment->max_coord - segment->min_coord; 1700 1701 prev_segment = segment; 1702 prev_min_pos = min_pos; 1703 prev_max_pos = max_pos; 1704 prev_min_coord = min_coord; 1705 prev_max_coord = max_coord; 1706 prev_min_flags = min_flags; 1707 prev_max_flags = max_flags; 1708 prev_min_on_coord = min_on_coord; 1709 prev_max_on_coord = max_on_coord; 1710 } 1711 else 1712 { 1713 /* points are the same: we don't create a new segment but */ 1714 /* merge the current segment with the previous one */ 1715 1716 if ( prev_segment->last->in_dir == point->in_dir ) 1717 { 1718 /* we have identical directions (this can happen for */ 1719 /* degenerate outlines that move zig-zag along the main */ 1720 /* axis without changing the coordinate value of the other */ 1721 /* axis, and where the segments have just been merged): */ 1722 /* unify segments */ 1723 1724 /* update constraints */ 1725 1726 if ( prev_min_pos < min_pos ) 1727 min_pos = prev_min_pos; 1728 if ( prev_max_pos > max_pos ) 1729 max_pos = prev_max_pos; 1730 1731 if ( prev_min_coord < min_coord ) 1732 { 1733 min_coord = prev_min_coord; 1734 min_flags = prev_min_flags; 1735 } 1736 if ( prev_max_coord > max_coord ) 1737 { 1738 max_coord = prev_max_coord; 1739 max_flags = prev_max_flags; 1740 } 1741 1742 if ( prev_min_on_coord < min_on_coord ) 1743 min_on_coord = prev_min_on_coord; 1744 if ( prev_max_on_coord > max_on_coord ) 1745 max_on_coord = prev_max_on_coord; 1746 1747 prev_segment->last = point; 1748 prev_segment->pos = (FT_Short)( ( min_pos + 1749 max_pos ) >> 1 ); 1750 prev_segment->delta = (FT_Short)( ( max_pos - 1751 min_pos ) >> 1 ); 1752 1753 if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL && 1754 ( max_on_coord - min_on_coord ) < flat_threshold ) 1755 prev_segment->flags |= AF_EDGE_ROUND; 1756 else 1757 prev_segment->flags &= ~AF_EDGE_ROUND; 1758 1759 prev_segment->min_coord = (FT_Short)min_coord; 1760 prev_segment->max_coord = (FT_Short)max_coord; 1761 prev_segment->height = prev_segment->max_coord - 1762 prev_segment->min_coord; 1763 } 1764 else 1765 { 1766 /* we have different directions; use the properties of the */ 1767 /* longer segment and discard the other one */ 1768 1769 if ( FT_ABS( prev_max_coord - prev_min_coord ) > 1770 FT_ABS( max_coord - min_coord ) ) 1771 { 1772 /* discard current segment */ 1773 1774 if ( min_pos < prev_min_pos ) 1775 prev_min_pos = min_pos; 1776 if ( max_pos > prev_max_pos ) 1777 prev_max_pos = max_pos; 1778 1779 prev_segment->last = point; 1780 prev_segment->pos = (FT_Short)( ( prev_min_pos + 1781 prev_max_pos ) >> 1 ); 1782 prev_segment->delta = (FT_Short)( ( prev_max_pos - 1783 prev_min_pos ) >> 1 ); 1784 } 1785 else 1786 { 1787 /* discard previous segment */ 1788 1789 if ( prev_min_pos < min_pos ) 1790 min_pos = prev_min_pos; 1791 if ( prev_max_pos > max_pos ) 1792 max_pos = prev_max_pos; 1793 1794 segment->last = point; 1795 segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); 1796 segment->delta = (FT_Short)( ( max_pos - min_pos ) >> 1 ); 1797 1798 if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL && 1799 ( max_on_coord - min_on_coord ) < flat_threshold ) 1800 segment->flags |= AF_EDGE_ROUND; 1801 1802 segment->min_coord = (FT_Short)min_coord; 1803 segment->max_coord = (FT_Short)max_coord; 1804 segment->height = segment->max_coord - 1805 segment->min_coord; 1806 1807 *prev_segment = *segment; 1808 1809 prev_min_pos = min_pos; 1810 prev_max_pos = max_pos; 1811 prev_min_coord = min_coord; 1812 prev_max_coord = max_coord; 1813 prev_min_flags = min_flags; 1814 prev_max_flags = max_flags; 1815 prev_min_on_coord = min_on_coord; 1816 prev_max_on_coord = max_on_coord; 1817 } 1818 } 1819 1820 axis->num_segments--; 1821 } 1822 1823 on_edge = 0; 1824 segment = NULL; 1825 1826 /* fall through */ 1827 } 1828 } 1829 1830 /* now exit if we are at the start/end point */ 1831 if ( point == last ) 1832 { 1833 if ( passed ) 1834 break; 1835 passed = 1; 1836 } 1837 1838 /* if we are not on an edge, check whether the major direction */ 1839 /* coincides with the current point's `out' direction, or */ 1840 /* whether we have a single-point contour */ 1841 if ( !on_edge && 1842 ( FT_ABS( point->out_dir ) == major_dir || 1843 point == point->prev ) ) 1844 { 1845 /* 1846 * For efficiency, we restrict the number of segments to 1000, 1847 * which is a heuristic value: it is very unlikely that a glyph 1848 * with so many segments can be hinted in a sensible way. 1849 * Reasons: 1850 * 1851 * - The glyph has really 1000 segments; this implies that it has 1852 * at least 2000 outline points. Assuming 'normal' fonts that 1853 * have superfluous points optimized away, viewing such a glyph 1854 * only makes sense at large magnifications where hinting 1855 * isn't applied anyway. 1856 * 1857 * - We have a broken glyph. Hinting doesn't make sense in this 1858 * case either. 1859 */ 1860 if ( axis->num_segments > 1000 ) 1861 { 1862 FT_TRACE0(( "af_latin_hints_compute_segments:" 1863 " more than 1000 segments in this glyph;\n" )); 1864 FT_TRACE0(( " " 1865 " hinting is suppressed\n" )); 1866 axis->num_segments = 0; 1867 return FT_Err_Ok; 1868 } 1869 1870 /* this is the start of a new segment! */ 1871 segment_dir = (AF_Direction)point->out_dir; 1872 1873 error = af_axis_hints_new_segment( axis, memory, &segment ); 1874 if ( error ) 1875 goto Exit; 1876 1877 /* clear all segment fields */ 1878 segment[0] = seg0; 1879 1880 segment->dir = (FT_Char)segment_dir; 1881 segment->first = point; 1882 segment->last = point; 1883 1884 /* `af_axis_hints_new_segment' reallocates memory, */ 1885 /* thus we have to refresh the `prev_segment' pointer */ 1886 if ( prev_segment ) 1887 prev_segment = segment - 1; 1888 1889 min_pos = max_pos = point->u; 1890 min_coord = max_coord = point->v; 1891 min_flags = max_flags = point->flags; 1892 1893 if ( point->flags & AF_FLAG_CONTROL ) 1894 { 1895 min_on_coord = 32000; 1896 max_on_coord = -32000; 1897 } 1898 else 1899 min_on_coord = max_on_coord = point->v; 1900 1901 on_edge = 1; 1902 1903 if ( point == point->prev ) 1904 { 1905 /* we have a one-point segment: this is a one-point */ 1906 /* contour with `in' and `out' direction set to */ 1907 /* AF_DIR_NONE */ 1908 segment->pos = (FT_Short)min_pos; 1909 1910 if (point->flags & AF_FLAG_CONTROL) 1911 segment->flags |= AF_EDGE_ROUND; 1912 1913 segment->min_coord = (FT_Short)point->v; 1914 segment->max_coord = (FT_Short)point->v; 1915 segment->height = 0; 1916 1917 on_edge = 0; 1918 segment = NULL; 1919 } 1920 } 1921 1922 point = point->next; 1923 } 1924 1925 } /* contours */ 1926 1927 1928 /* now slightly increase the height of segments if this makes */ 1929 /* sense -- this is used to better detect and ignore serifs */ 1930 { 1931 AF_Segment segments = axis->segments; 1932 AF_Segment segments_end = FT_OFFSET( segments, axis->num_segments ); 1933 1934 1935 for ( segment = segments; segment < segments_end; segment++ ) 1936 { 1937 AF_Point first = segment->first; 1938 AF_Point last = segment->last; 1939 FT_Pos first_v = first->v; 1940 FT_Pos last_v = last->v; 1941 1942 1943 if ( first_v < last_v ) 1944 { 1945 AF_Point p; 1946 1947 1948 p = first->prev; 1949 if ( p->v < first_v ) 1950 segment->height = (FT_Short)( segment->height + 1951 ( ( first_v - p->v ) >> 1 ) ); 1952 1953 p = last->next; 1954 if ( p->v > last_v ) 1955 segment->height = (FT_Short)( segment->height + 1956 ( ( p->v - last_v ) >> 1 ) ); 1957 } 1958 else 1959 { 1960 AF_Point p; 1961 1962 1963 p = first->prev; 1964 if ( p->v > first_v ) 1965 segment->height = (FT_Short)( segment->height + 1966 ( ( p->v - first_v ) >> 1 ) ); 1967 1968 p = last->next; 1969 if ( p->v < last_v ) 1970 segment->height = (FT_Short)( segment->height + 1971 ( ( last_v - p->v ) >> 1 ) ); 1972 } 1973 } 1974 } 1975 1976 Exit: 1977 return error; 1978 } 1979 1980 1981 /* Link segments to form stems and serifs. If `width_count' and */ 1982 /* `widths' are non-zero, use them to fine-tune the scoring function. */ 1983 1984 FT_LOCAL_DEF( void ) af_latin_hints_link_segments(AF_GlyphHints hints,FT_UInt width_count,AF_WidthRec * widths,AF_Dimension dim)1985 af_latin_hints_link_segments( AF_GlyphHints hints, 1986 FT_UInt width_count, 1987 AF_WidthRec* widths, 1988 AF_Dimension dim ) 1989 { 1990 AF_AxisHints axis = &hints->axis[dim]; 1991 AF_Segment segments = axis->segments; 1992 AF_Segment segment_limit = segments + axis->num_segments; 1993 FT_Pos len_threshold, len_score, dist_score, max_width; 1994 AF_Segment seg1, seg2; 1995 1996 1997 if ( width_count ) 1998 max_width = widths[width_count - 1].org; 1999 else 2000 max_width = 0; 2001 2002 /* a heuristic value to set up a minimum value for overlapping */ 2003 len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 ); 2004 if ( len_threshold == 0 ) 2005 len_threshold = 1; 2006 2007 /* a heuristic value to weight lengths */ 2008 len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 ); 2009 2010 /* a heuristic value to weight distances (no call to */ 2011 /* AF_LATIN_CONSTANT needed, since we work on multiples */ 2012 /* of the stem width) */ 2013 dist_score = 3000; 2014 2015 /* now compare each segment to the others */ 2016 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 2017 { 2018 if ( seg1->dir != axis->major_dir ) 2019 continue; 2020 2021 /* search for stems having opposite directions, */ 2022 /* with seg1 to the `left' of seg2 */ 2023 for ( seg2 = segments; seg2 < segment_limit; seg2++ ) 2024 { 2025 FT_Pos pos1 = seg1->pos; 2026 FT_Pos pos2 = seg2->pos; 2027 2028 2029 if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 ) 2030 { 2031 /* compute distance between the two segments */ 2032 FT_Pos min = seg1->min_coord; 2033 FT_Pos max = seg1->max_coord; 2034 FT_Pos len; 2035 2036 2037 if ( min < seg2->min_coord ) 2038 min = seg2->min_coord; 2039 2040 if ( max > seg2->max_coord ) 2041 max = seg2->max_coord; 2042 2043 /* compute maximum coordinate difference of the two segments */ 2044 /* (this is, how much they overlap) */ 2045 len = max - min; 2046 if ( len >= len_threshold ) 2047 { 2048 /* 2049 * The score is the sum of two demerits indicating the 2050 * `badness' of a fit, measured along the segments' main axis 2051 * and orthogonal to it, respectively. 2052 * 2053 * - The less overlapping along the main axis, the worse it 2054 * is, causing a larger demerit. 2055 * 2056 * - The nearer the orthogonal distance to a stem width, the 2057 * better it is, causing a smaller demerit. For simplicity, 2058 * however, we only increase the demerit for values that 2059 * exceed the largest stem width. 2060 */ 2061 2062 FT_Pos dist = pos2 - pos1; 2063 2064 FT_Pos dist_demerit, score; 2065 2066 2067 if ( max_width ) 2068 { 2069 /* distance demerits are based on multiples of `max_width'; */ 2070 /* we scale by 1024 for getting more precision */ 2071 FT_Pos delta = ( dist << 10 ) / max_width - ( 1 << 10 ); 2072 2073 2074 if ( delta > 10000 ) 2075 dist_demerit = 32000; 2076 else if ( delta > 0 ) 2077 dist_demerit = delta * delta / dist_score; 2078 else 2079 dist_demerit = 0; 2080 } 2081 else 2082 dist_demerit = dist; /* default if no widths available */ 2083 2084 score = dist_demerit + len_score / len; 2085 2086 /* and we search for the smallest score */ 2087 if ( score < seg1->score ) 2088 { 2089 seg1->score = score; 2090 seg1->link = seg2; 2091 } 2092 2093 if ( score < seg2->score ) 2094 { 2095 seg2->score = score; 2096 seg2->link = seg1; 2097 } 2098 } 2099 } 2100 } 2101 } 2102 2103 /* now compute the `serif' segments, cf. explanations in `afhints.h' */ 2104 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 2105 { 2106 seg2 = seg1->link; 2107 2108 if ( seg2 ) 2109 { 2110 if ( seg2->link != seg1 ) 2111 { 2112 seg1->link = NULL; 2113 seg1->serif = seg2->link; 2114 } 2115 } 2116 } 2117 } 2118 2119 2120 /* Link segments to edges, using feature analysis for selection. */ 2121 2122 FT_LOCAL_DEF( FT_Error ) af_latin_hints_compute_edges(AF_GlyphHints hints,AF_Dimension dim)2123 af_latin_hints_compute_edges( AF_GlyphHints hints, 2124 AF_Dimension dim ) 2125 { 2126 AF_AxisHints axis = &hints->axis[dim]; 2127 FT_Error error = FT_Err_Ok; 2128 FT_Memory memory = hints->memory; 2129 AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim]; 2130 2131 AF_StyleClass style_class = hints->metrics->style_class; 2132 AF_ScriptClass script_class = af_script_classes[style_class->script]; 2133 2134 FT_Bool top_to_bottom_hinting = 0; 2135 2136 AF_Segment segments = axis->segments; 2137 AF_Segment segment_limit = segments + axis->num_segments; 2138 AF_Segment seg; 2139 2140 #if 0 2141 AF_Direction up_dir; 2142 #endif 2143 FT_Fixed scale; 2144 FT_Pos edge_distance_threshold; 2145 FT_Pos segment_length_threshold; 2146 FT_Pos segment_width_threshold; 2147 2148 2149 axis->num_edges = 0; 2150 2151 scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale 2152 : hints->y_scale; 2153 2154 #if 0 2155 up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP 2156 : AF_DIR_RIGHT; 2157 #endif 2158 2159 if ( dim == AF_DIMENSION_VERT ) 2160 top_to_bottom_hinting = script_class->top_to_bottom_hinting; 2161 2162 /* 2163 * We ignore all segments that are less than 1 pixel in length 2164 * to avoid many problems with serif fonts. We compute the 2165 * corresponding threshold in font units. 2166 */ 2167 if ( dim == AF_DIMENSION_HORZ ) 2168 segment_length_threshold = FT_DivFix( 64, hints->y_scale ); 2169 else 2170 segment_length_threshold = 0; 2171 2172 /* 2173 * Similarly, we ignore segments that have a width delta 2174 * larger than 0.5px (i.e., a width larger than 1px). 2175 */ 2176 segment_width_threshold = FT_DivFix( 32, scale ); 2177 2178 /********************************************************************** 2179 * 2180 * We begin by generating a sorted table of edges for the current 2181 * direction. To do so, we simply scan each segment and try to find 2182 * an edge in our table that corresponds to its position. 2183 * 2184 * If no edge is found, we create and insert a new edge in the 2185 * sorted table. Otherwise, we simply add the segment to the edge's 2186 * list which gets processed in the second step to compute the 2187 * edge's properties. 2188 * 2189 * Note that the table of edges is sorted along the segment/edge 2190 * position. 2191 * 2192 */ 2193 2194 /* assure that edge distance threshold is at most 0.25px */ 2195 edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold, 2196 scale ); 2197 if ( edge_distance_threshold > 64 / 4 ) 2198 edge_distance_threshold = 64 / 4; 2199 2200 edge_distance_threshold = FT_DivFix( edge_distance_threshold, 2201 scale ); 2202 2203 for ( seg = segments; seg < segment_limit; seg++ ) 2204 { 2205 AF_Edge found = NULL; 2206 FT_Int ee; 2207 2208 2209 /* ignore too short segments, too wide ones, and, in this loop, */ 2210 /* one-point segments without a direction */ 2211 if ( seg->height < segment_length_threshold || 2212 seg->delta > segment_width_threshold || 2213 seg->dir == AF_DIR_NONE ) 2214 continue; 2215 2216 /* A special case for serif edges: If they are smaller than */ 2217 /* 1.5 pixels we ignore them. */ 2218 if ( seg->serif && 2219 2 * seg->height < 3 * segment_length_threshold ) 2220 continue; 2221 2222 /* look for an edge corresponding to the segment */ 2223 for ( ee = 0; ee < axis->num_edges; ee++ ) 2224 { 2225 AF_Edge edge = axis->edges + ee; 2226 FT_Pos dist; 2227 2228 2229 dist = seg->pos - edge->fpos; 2230 if ( dist < 0 ) 2231 dist = -dist; 2232 2233 if ( dist < edge_distance_threshold && edge->dir == seg->dir ) 2234 { 2235 found = edge; 2236 break; 2237 } 2238 } 2239 2240 if ( !found ) 2241 { 2242 AF_Edge edge; 2243 2244 2245 /* insert a new edge in the list and */ 2246 /* sort according to the position */ 2247 error = af_axis_hints_new_edge( axis, seg->pos, 2248 (AF_Direction)seg->dir, 2249 top_to_bottom_hinting, 2250 memory, &edge ); 2251 if ( error ) 2252 goto Exit; 2253 2254 /* add the segment to the new edge's list */ 2255 FT_ZERO( edge ); 2256 2257 edge->first = seg; 2258 edge->last = seg; 2259 edge->dir = seg->dir; 2260 edge->fpos = seg->pos; 2261 edge->opos = FT_MulFix( seg->pos, scale ); 2262 edge->pos = edge->opos; 2263 seg->edge_next = seg; 2264 } 2265 else 2266 { 2267 /* if an edge was found, simply add the segment to the edge's */ 2268 /* list */ 2269 seg->edge_next = found->first; 2270 found->last->edge_next = seg; 2271 found->last = seg; 2272 } 2273 } 2274 2275 /* we loop again over all segments to catch one-point segments */ 2276 /* without a direction: if possible, link them to existing edges */ 2277 for ( seg = segments; seg < segment_limit; seg++ ) 2278 { 2279 AF_Edge found = NULL; 2280 FT_Int ee; 2281 2282 2283 if ( seg->dir != AF_DIR_NONE ) 2284 continue; 2285 2286 /* look for an edge corresponding to the segment */ 2287 for ( ee = 0; ee < axis->num_edges; ee++ ) 2288 { 2289 AF_Edge edge = axis->edges + ee; 2290 FT_Pos dist; 2291 2292 2293 dist = seg->pos - edge->fpos; 2294 if ( dist < 0 ) 2295 dist = -dist; 2296 2297 if ( dist < edge_distance_threshold ) 2298 { 2299 found = edge; 2300 break; 2301 } 2302 } 2303 2304 /* one-point segments without a match are ignored */ 2305 if ( found ) 2306 { 2307 seg->edge_next = found->first; 2308 found->last->edge_next = seg; 2309 found->last = seg; 2310 } 2311 } 2312 2313 2314 /******************************************************************* 2315 * 2316 * Good, we now compute each edge's properties according to the 2317 * segments found on its position. Basically, these are 2318 * 2319 * - the edge's main direction 2320 * - stem edge, serif edge or both (which defaults to stem then) 2321 * - rounded edge, straight or both (which defaults to straight) 2322 * - link for edge 2323 * 2324 */ 2325 2326 /* first of all, set the `edge' field in each segment -- this is */ 2327 /* required in order to compute edge links */ 2328 2329 /* 2330 * Note that removing this loop and setting the `edge' field of each 2331 * segment directly in the code above slows down execution speed for 2332 * some reasons on platforms like the Sun. 2333 */ 2334 { 2335 AF_Edge edges = axis->edges; 2336 AF_Edge edge_limit = FT_OFFSET( edges, axis->num_edges ); 2337 AF_Edge edge; 2338 2339 2340 for ( edge = edges; edge < edge_limit; edge++ ) 2341 { 2342 seg = edge->first; 2343 if ( seg ) 2344 do 2345 { 2346 seg->edge = edge; 2347 seg = seg->edge_next; 2348 2349 } while ( seg != edge->first ); 2350 } 2351 2352 /* now compute each edge properties */ 2353 for ( edge = edges; edge < edge_limit; edge++ ) 2354 { 2355 FT_Int is_round = 0; /* does it contain round segments? */ 2356 FT_Int is_straight = 0; /* does it contain straight segments? */ 2357 #if 0 2358 FT_Pos ups = 0; /* number of upwards segments */ 2359 FT_Pos downs = 0; /* number of downwards segments */ 2360 #endif 2361 2362 2363 seg = edge->first; 2364 2365 do 2366 { 2367 FT_Bool is_serif; 2368 2369 2370 /* check for roundness of segment */ 2371 if ( seg->flags & AF_EDGE_ROUND ) 2372 is_round++; 2373 else 2374 is_straight++; 2375 2376 #if 0 2377 /* check for segment direction */ 2378 if ( seg->dir == up_dir ) 2379 ups += seg->max_coord - seg->min_coord; 2380 else 2381 downs += seg->max_coord - seg->min_coord; 2382 #endif 2383 2384 /* check for links -- if seg->serif is set, then seg->link must */ 2385 /* be ignored */ 2386 is_serif = FT_BOOL( seg->serif && 2387 seg->serif->edge && 2388 seg->serif->edge != edge ); 2389 2390 if ( ( seg->link && seg->link->edge ) || is_serif ) 2391 { 2392 AF_Edge edge2; 2393 AF_Segment seg2; 2394 2395 2396 edge2 = edge->link; 2397 seg2 = seg->link; 2398 2399 if ( is_serif ) 2400 { 2401 seg2 = seg->serif; 2402 edge2 = edge->serif; 2403 } 2404 2405 if ( edge2 ) 2406 { 2407 FT_Pos edge_delta; 2408 FT_Pos seg_delta; 2409 2410 2411 edge_delta = edge->fpos - edge2->fpos; 2412 if ( edge_delta < 0 ) 2413 edge_delta = -edge_delta; 2414 2415 seg_delta = seg->pos - seg2->pos; 2416 if ( seg_delta < 0 ) 2417 seg_delta = -seg_delta; 2418 2419 if ( seg_delta < edge_delta ) 2420 edge2 = seg2->edge; 2421 } 2422 else 2423 edge2 = seg2->edge; 2424 2425 if ( is_serif ) 2426 { 2427 edge->serif = edge2; 2428 edge2->flags |= AF_EDGE_SERIF; 2429 } 2430 else 2431 edge->link = edge2; 2432 } 2433 2434 seg = seg->edge_next; 2435 2436 } while ( seg != edge->first ); 2437 2438 /* set the round/straight flags */ 2439 edge->flags = AF_EDGE_NORMAL; 2440 2441 if ( is_round > 0 && is_round >= is_straight ) 2442 edge->flags |= AF_EDGE_ROUND; 2443 2444 #if 0 2445 /* set the edge's main direction */ 2446 edge->dir = AF_DIR_NONE; 2447 2448 if ( ups > downs ) 2449 edge->dir = (FT_Char)up_dir; 2450 2451 else if ( ups < downs ) 2452 edge->dir = (FT_Char)-up_dir; 2453 2454 else if ( ups == downs ) 2455 edge->dir = 0; /* both up and down! */ 2456 #endif 2457 2458 /* get rid of serifs if link is set */ 2459 /* XXX: This gets rid of many unpleasant artefacts! */ 2460 /* Example: the `c' in cour.pfa at size 13 */ 2461 2462 if ( edge->serif && edge->link ) 2463 edge->serif = NULL; 2464 } 2465 } 2466 2467 Exit: 2468 return error; 2469 } 2470 2471 2472 /* Detect segments and edges for given dimension. */ 2473 2474 FT_LOCAL_DEF( FT_Error ) af_latin_hints_detect_features(AF_GlyphHints hints,FT_UInt width_count,AF_WidthRec * widths,AF_Dimension dim)2475 af_latin_hints_detect_features( AF_GlyphHints hints, 2476 FT_UInt width_count, 2477 AF_WidthRec* widths, 2478 AF_Dimension dim ) 2479 { 2480 FT_Error error; 2481 2482 2483 error = af_latin_hints_compute_segments( hints, dim ); 2484 if ( !error ) 2485 { 2486 af_latin_hints_link_segments( hints, width_count, widths, dim ); 2487 2488 error = af_latin_hints_compute_edges( hints, dim ); 2489 } 2490 2491 return error; 2492 } 2493 2494 2495 /* Compute all edges which lie within blue zones. */ 2496 2497 static void af_latin_hints_compute_blue_edges(AF_GlyphHints hints,AF_LatinMetrics metrics)2498 af_latin_hints_compute_blue_edges( AF_GlyphHints hints, 2499 AF_LatinMetrics metrics ) 2500 { 2501 AF_AxisHints axis = &hints->axis[AF_DIMENSION_VERT]; 2502 AF_Edge edge = axis->edges; 2503 AF_Edge edge_limit = edge + axis->num_edges; 2504 AF_LatinAxis latin = &metrics->axis[AF_DIMENSION_VERT]; 2505 FT_Fixed scale = latin->scale; 2506 2507 2508 /* compute which blue zones are active, i.e. have their scaled */ 2509 /* size < 3/4 pixels */ 2510 2511 /* for each horizontal edge search the blue zone which is closest */ 2512 for ( ; edge < edge_limit; edge++ ) 2513 { 2514 FT_UInt bb; 2515 AF_Width best_blue = NULL; 2516 FT_Bool best_blue_is_neutral = 0; 2517 FT_Pos best_dist; /* initial threshold */ 2518 2519 2520 /* compute the initial threshold as a fraction of the EM size */ 2521 /* (the value 40 is heuristic) */ 2522 best_dist = FT_MulFix( metrics->units_per_em / 40, scale ); 2523 2524 /* assure a minimum distance of 0.5px */ 2525 if ( best_dist > 64 / 2 ) 2526 best_dist = 64 / 2; 2527 2528 for ( bb = 0; bb < latin->blue_count; bb++ ) 2529 { 2530 AF_LatinBlue blue = latin->blues + bb; 2531 FT_Bool is_top_blue, is_neutral_blue, is_major_dir; 2532 2533 2534 /* skip inactive blue zones (i.e., those that are too large) */ 2535 if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) 2536 continue; 2537 2538 /* if it is a top zone, check for right edges (against the major */ 2539 /* direction); if it is a bottom zone, check for left edges (in */ 2540 /* the major direction) -- this assumes the TrueType convention */ 2541 /* for the orientation of contours */ 2542 is_top_blue = 2543 (FT_Byte)( ( blue->flags & ( AF_LATIN_BLUE_TOP | 2544 AF_LATIN_BLUE_SUB_TOP ) ) != 0 ); 2545 is_neutral_blue = 2546 (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_NEUTRAL ) != 0); 2547 is_major_dir = 2548 FT_BOOL( edge->dir == axis->major_dir ); 2549 2550 /* neutral blue zones are handled for both directions */ 2551 if ( is_top_blue ^ is_major_dir || is_neutral_blue ) 2552 { 2553 FT_Pos dist; 2554 2555 2556 /* first of all, compare it to the reference position */ 2557 dist = edge->fpos - blue->ref.org; 2558 if ( dist < 0 ) 2559 dist = -dist; 2560 2561 dist = FT_MulFix( dist, scale ); 2562 if ( dist < best_dist ) 2563 { 2564 best_dist = dist; 2565 best_blue = &blue->ref; 2566 best_blue_is_neutral = is_neutral_blue; 2567 } 2568 2569 /* now compare it to the overshoot position and check whether */ 2570 /* the edge is rounded, and whether the edge is over the */ 2571 /* reference position of a top zone, or under the reference */ 2572 /* position of a bottom zone (provided we don't have a */ 2573 /* neutral blue zone) */ 2574 if ( edge->flags & AF_EDGE_ROUND && 2575 dist != 0 && 2576 !is_neutral_blue ) 2577 { 2578 FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org ); 2579 2580 2581 if ( is_top_blue ^ is_under_ref ) 2582 { 2583 dist = edge->fpos - blue->shoot.org; 2584 if ( dist < 0 ) 2585 dist = -dist; 2586 2587 dist = FT_MulFix( dist, scale ); 2588 if ( dist < best_dist ) 2589 { 2590 best_dist = dist; 2591 best_blue = &blue->shoot; 2592 best_blue_is_neutral = is_neutral_blue; 2593 } 2594 } 2595 } 2596 } 2597 } 2598 2599 if ( best_blue ) 2600 { 2601 edge->blue_edge = best_blue; 2602 if ( best_blue_is_neutral ) 2603 edge->flags |= AF_EDGE_NEUTRAL; 2604 } 2605 } 2606 } 2607 2608 2609 /* Initalize hinting engine. */ 2610 2611 static FT_Error af_latin_hints_init(AF_GlyphHints hints,AF_LatinMetrics metrics)2612 af_latin_hints_init( AF_GlyphHints hints, 2613 AF_LatinMetrics metrics ) 2614 { 2615 FT_Render_Mode mode; 2616 FT_UInt32 scaler_flags, other_flags; 2617 FT_Face face = metrics->root.scaler.face; 2618 2619 2620 af_glyph_hints_rescale( hints, (AF_StyleMetrics)metrics ); 2621 2622 /* 2623 * correct x_scale and y_scale if needed, since they may have 2624 * been modified by `af_latin_metrics_scale_dim' above 2625 */ 2626 hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale; 2627 hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta; 2628 hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale; 2629 hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta; 2630 2631 /* compute flags depending on render mode, etc. */ 2632 mode = metrics->root.scaler.render_mode; 2633 2634 scaler_flags = hints->scaler_flags; 2635 other_flags = 0; 2636 2637 /* 2638 * We snap the width of vertical stems for the monochrome and 2639 * horizontal LCD rendering targets only. 2640 */ 2641 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD ) 2642 other_flags |= AF_LATIN_HINTS_HORZ_SNAP; 2643 2644 /* 2645 * We snap the width of horizontal stems for the monochrome and 2646 * vertical LCD rendering targets only. 2647 */ 2648 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V ) 2649 other_flags |= AF_LATIN_HINTS_VERT_SNAP; 2650 2651 /* 2652 * We adjust stems to full pixels unless in `light' or `lcd' mode. 2653 */ 2654 if ( mode != FT_RENDER_MODE_LIGHT && mode != FT_RENDER_MODE_LCD ) 2655 other_flags |= AF_LATIN_HINTS_STEM_ADJUST; 2656 2657 if ( mode == FT_RENDER_MODE_MONO ) 2658 other_flags |= AF_LATIN_HINTS_MONO; 2659 2660 /* 2661 * In `light' or `lcd' mode we disable horizontal hinting completely. 2662 * We also do it if the face is italic. 2663 * 2664 * However, if warping is enabled (which only works in `light' hinting 2665 * mode), advance widths get adjusted, too. 2666 */ 2667 if ( mode == FT_RENDER_MODE_LIGHT || mode == FT_RENDER_MODE_LCD || 2668 ( face->style_flags & FT_STYLE_FLAG_ITALIC ) != 0 ) 2669 scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL; 2670 2671 hints->scaler_flags = scaler_flags; 2672 hints->other_flags = other_flags; 2673 2674 return FT_Err_Ok; 2675 } 2676 2677 2678 /*************************************************************************/ 2679 /*************************************************************************/ 2680 /***** *****/ 2681 /***** L A T I N G L Y P H G R I D - F I T T I N G *****/ 2682 /***** *****/ 2683 /*************************************************************************/ 2684 /*************************************************************************/ 2685 2686 /* Snap a given width in scaled coordinates to one of the */ 2687 /* current standard widths. */ 2688 2689 static FT_Pos af_latin_snap_width(AF_Width widths,FT_UInt count,FT_Pos width)2690 af_latin_snap_width( AF_Width widths, 2691 FT_UInt count, 2692 FT_Pos width ) 2693 { 2694 FT_UInt n; 2695 FT_Pos best = 64 + 32 + 2; 2696 FT_Pos reference = width; 2697 FT_Pos scaled; 2698 2699 2700 for ( n = 0; n < count; n++ ) 2701 { 2702 FT_Pos w; 2703 FT_Pos dist; 2704 2705 2706 w = widths[n].cur; 2707 dist = width - w; 2708 if ( dist < 0 ) 2709 dist = -dist; 2710 if ( dist < best ) 2711 { 2712 best = dist; 2713 reference = w; 2714 } 2715 } 2716 2717 scaled = FT_PIX_ROUND( reference ); 2718 2719 if ( width >= reference ) 2720 { 2721 if ( width < scaled + 48 ) 2722 width = reference; 2723 } 2724 else 2725 { 2726 if ( width > scaled - 48 ) 2727 width = reference; 2728 } 2729 2730 return width; 2731 } 2732 2733 2734 /* Compute the snapped width of a given stem, ignoring very thin ones. */ 2735 /* There is a lot of voodoo in this function; changing the hard-coded */ 2736 /* parameters influence the whole hinting process. */ 2737 2738 static FT_Pos af_latin_compute_stem_width(AF_GlyphHints hints,AF_Dimension dim,FT_Pos width,FT_Pos base_delta,FT_UInt base_flags,FT_UInt stem_flags)2739 af_latin_compute_stem_width( AF_GlyphHints hints, 2740 AF_Dimension dim, 2741 FT_Pos width, 2742 FT_Pos base_delta, 2743 FT_UInt base_flags, 2744 FT_UInt stem_flags ) 2745 { 2746 AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics; 2747 AF_LatinAxis axis = &metrics->axis[dim]; 2748 FT_Pos dist = width; 2749 FT_Int sign = 0; 2750 FT_Int vertical = ( dim == AF_DIMENSION_VERT ); 2751 2752 2753 if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) || 2754 axis->extra_light ) 2755 return width; 2756 2757 if ( dist < 0 ) 2758 { 2759 dist = -width; 2760 sign = 1; 2761 } 2762 2763 if ( ( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) || 2764 ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) ) 2765 { 2766 /* smooth hinting process: very lightly quantize the stem width */ 2767 2768 /* leave the widths of serifs alone */ 2769 if ( ( stem_flags & AF_EDGE_SERIF ) && 2770 vertical && 2771 ( dist < 3 * 64 ) ) 2772 goto Done_Width; 2773 2774 else if ( base_flags & AF_EDGE_ROUND ) 2775 { 2776 if ( dist < 80 ) 2777 dist = 64; 2778 } 2779 else if ( dist < 56 ) 2780 dist = 56; 2781 2782 if ( axis->width_count > 0 ) 2783 { 2784 FT_Pos delta; 2785 2786 2787 /* compare to standard width */ 2788 delta = dist - axis->widths[0].cur; 2789 2790 if ( delta < 0 ) 2791 delta = -delta; 2792 2793 if ( delta < 40 ) 2794 { 2795 dist = axis->widths[0].cur; 2796 if ( dist < 48 ) 2797 dist = 48; 2798 2799 goto Done_Width; 2800 } 2801 2802 if ( dist < 3 * 64 ) 2803 { 2804 delta = dist & 63; 2805 dist &= -64; 2806 2807 if ( delta < 10 ) 2808 dist += delta; 2809 2810 else if ( delta < 32 ) 2811 dist += 10; 2812 2813 else if ( delta < 54 ) 2814 dist += 54; 2815 2816 else 2817 dist += delta; 2818 } 2819 else 2820 { 2821 /* A stem's end position depends on two values: the start */ 2822 /* position and the stem length. The former gets usually */ 2823 /* rounded to the grid, while the latter gets rounded also if it */ 2824 /* exceeds a certain length (see below in this function). This */ 2825 /* `double rounding' can lead to a great difference to the */ 2826 /* original, unhinted position; this normally doesn't matter for */ 2827 /* large PPEM values, but for small sizes it can easily make */ 2828 /* outlines collide. For this reason, we adjust the stem length */ 2829 /* by a small amount depending on the PPEM value in case the */ 2830 /* former and latter rounding both point into the same */ 2831 /* direction. */ 2832 2833 FT_Pos bdelta = 0; 2834 2835 2836 if ( ( ( width > 0 ) && ( base_delta > 0 ) ) || 2837 ( ( width < 0 ) && ( base_delta < 0 ) ) ) 2838 { 2839 FT_UInt ppem = metrics->root.scaler.face->size->metrics.x_ppem; 2840 2841 2842 if ( ppem < 10 ) 2843 bdelta = base_delta; 2844 else if ( ppem < 30 ) 2845 bdelta = ( base_delta * (FT_Pos)( 30 - ppem ) ) / 20; 2846 2847 if ( bdelta < 0 ) 2848 bdelta = -bdelta; 2849 } 2850 2851 dist = ( dist - bdelta + 32 ) & ~63; 2852 } 2853 } 2854 } 2855 else 2856 { 2857 /* strong hinting process: snap the stem width to integer pixels */ 2858 2859 FT_Pos org_dist = dist; 2860 2861 2862 dist = af_latin_snap_width( axis->widths, axis->width_count, dist ); 2863 2864 if ( vertical ) 2865 { 2866 /* in the case of vertical hinting, always round */ 2867 /* the stem heights to integer pixels */ 2868 2869 if ( dist >= 64 ) 2870 dist = ( dist + 16 ) & ~63; 2871 else 2872 dist = 64; 2873 } 2874 else 2875 { 2876 if ( AF_LATIN_HINTS_DO_MONO( hints ) ) 2877 { 2878 /* monochrome horizontal hinting: snap widths to integer pixels */ 2879 /* with a different threshold */ 2880 2881 if ( dist < 64 ) 2882 dist = 64; 2883 else 2884 dist = ( dist + 32 ) & ~63; 2885 } 2886 else 2887 { 2888 /* for horizontal anti-aliased hinting, we adopt a more subtle */ 2889 /* approach: we strengthen small stems, round stems whose size */ 2890 /* is between 1 and 2 pixels to an integer, otherwise nothing */ 2891 2892 if ( dist < 48 ) 2893 dist = ( dist + 64 ) >> 1; 2894 2895 else if ( dist < 128 ) 2896 { 2897 /* We only round to an integer width if the corresponding */ 2898 /* distortion is less than 1/4 pixel. Otherwise this */ 2899 /* makes everything worse since the diagonals, which are */ 2900 /* not hinted, appear a lot bolder or thinner than the */ 2901 /* vertical stems. */ 2902 2903 FT_Pos delta; 2904 2905 2906 dist = ( dist + 22 ) & ~63; 2907 delta = dist - org_dist; 2908 if ( delta < 0 ) 2909 delta = -delta; 2910 2911 if ( delta >= 16 ) 2912 { 2913 dist = org_dist; 2914 if ( dist < 48 ) 2915 dist = ( dist + 64 ) >> 1; 2916 } 2917 } 2918 else 2919 /* round otherwise to prevent color fringes in LCD mode */ 2920 dist = ( dist + 32 ) & ~63; 2921 } 2922 } 2923 } 2924 2925 Done_Width: 2926 if ( sign ) 2927 dist = -dist; 2928 2929 return dist; 2930 } 2931 2932 2933 /* Align one stem edge relative to the previous stem edge. */ 2934 2935 static void af_latin_align_linked_edge(AF_GlyphHints hints,AF_Dimension dim,AF_Edge base_edge,AF_Edge stem_edge)2936 af_latin_align_linked_edge( AF_GlyphHints hints, 2937 AF_Dimension dim, 2938 AF_Edge base_edge, 2939 AF_Edge stem_edge ) 2940 { 2941 FT_Pos dist, base_delta; 2942 FT_Pos fitted_width; 2943 2944 2945 dist = stem_edge->opos - base_edge->opos; 2946 base_delta = base_edge->pos - base_edge->opos; 2947 2948 fitted_width = af_latin_compute_stem_width( hints, dim, 2949 dist, base_delta, 2950 base_edge->flags, 2951 stem_edge->flags ); 2952 2953 2954 stem_edge->pos = base_edge->pos + fitted_width; 2955 2956 FT_TRACE5(( " LINK: edge %ld (opos=%.2f) linked to %.2f," 2957 " dist was %.2f, now %.2f\n", 2958 stem_edge - hints->axis[dim].edges, stem_edge->opos / 64.0, 2959 stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 )); 2960 } 2961 2962 2963 /* Shift the coordinates of the `serif' edge by the same amount */ 2964 /* as the corresponding `base' edge has been moved already. */ 2965 2966 static void af_latin_align_serif_edge(AF_GlyphHints hints,AF_Edge base,AF_Edge serif)2967 af_latin_align_serif_edge( AF_GlyphHints hints, 2968 AF_Edge base, 2969 AF_Edge serif ) 2970 { 2971 FT_UNUSED( hints ); 2972 2973 serif->pos = base->pos + ( serif->opos - base->opos ); 2974 } 2975 2976 2977 /*************************************************************************/ 2978 /*************************************************************************/ 2979 /*************************************************************************/ 2980 /**** ****/ 2981 /**** E D G E H I N T I N G ****/ 2982 /**** ****/ 2983 /*************************************************************************/ 2984 /*************************************************************************/ 2985 /*************************************************************************/ 2986 2987 2988 /* The main grid-fitting routine. */ 2989 2990 static void af_latin_hint_edges(AF_GlyphHints hints,AF_Dimension dim)2991 af_latin_hint_edges( AF_GlyphHints hints, 2992 AF_Dimension dim ) 2993 { 2994 AF_AxisHints axis = &hints->axis[dim]; 2995 AF_Edge edges = axis->edges; 2996 AF_Edge edge_limit = edges + axis->num_edges; 2997 FT_PtrDist n_edges; 2998 AF_Edge edge; 2999 AF_Edge anchor = NULL; 3000 FT_Int has_serifs = 0; 3001 3002 AF_StyleClass style_class = hints->metrics->style_class; 3003 AF_ScriptClass script_class = af_script_classes[style_class->script]; 3004 3005 FT_Bool top_to_bottom_hinting = 0; 3006 3007 #ifdef FT_DEBUG_LEVEL_TRACE 3008 FT_UInt num_actions = 0; 3009 #endif 3010 3011 3012 FT_TRACE5(( "latin %s edge hinting (style `%s')\n", 3013 dim == AF_DIMENSION_VERT ? "horizontal" : "vertical", 3014 af_style_names[hints->metrics->style_class->style] )); 3015 3016 if ( dim == AF_DIMENSION_VERT ) 3017 top_to_bottom_hinting = script_class->top_to_bottom_hinting; 3018 3019 /* we begin by aligning all stems relative to the blue zone */ 3020 /* if needed -- that's only for horizontal edges */ 3021 3022 if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) ) 3023 { 3024 for ( edge = edges; edge < edge_limit; edge++ ) 3025 { 3026 AF_Width blue; 3027 AF_Edge edge1, edge2; /* these edges form the stem to check */ 3028 3029 3030 if ( edge->flags & AF_EDGE_DONE ) 3031 continue; 3032 3033 edge1 = NULL; 3034 edge2 = edge->link; 3035 3036 /* 3037 * If a stem contains both a neutral and a non-neutral blue zone, 3038 * skip the neutral one. Otherwise, outlines with different 3039 * directions might be incorrectly aligned at the same vertical 3040 * position. 3041 * 3042 * If we have two neutral blue zones, skip one of them. 3043 * 3044 */ 3045 if ( edge->blue_edge && edge2 && edge2->blue_edge ) 3046 { 3047 FT_Byte neutral = edge->flags & AF_EDGE_NEUTRAL; 3048 FT_Byte neutral2 = edge2->flags & AF_EDGE_NEUTRAL; 3049 3050 3051 if ( neutral2 ) 3052 { 3053 edge2->blue_edge = NULL; 3054 edge2->flags &= ~AF_EDGE_NEUTRAL; 3055 } 3056 else if ( neutral ) 3057 { 3058 edge->blue_edge = NULL; 3059 edge->flags &= ~AF_EDGE_NEUTRAL; 3060 } 3061 } 3062 3063 blue = edge->blue_edge; 3064 if ( blue ) 3065 edge1 = edge; 3066 3067 /* flip edges if the other edge is aligned to a blue zone */ 3068 else if ( edge2 && edge2->blue_edge ) 3069 { 3070 blue = edge2->blue_edge; 3071 edge1 = edge2; 3072 edge2 = edge; 3073 } 3074 3075 if ( !edge1 ) 3076 continue; 3077 3078 #ifdef FT_DEBUG_LEVEL_TRACE 3079 if ( !anchor ) 3080 FT_TRACE5(( " BLUE_ANCHOR: edge %ld (opos=%.2f) snapped to %.2f," 3081 " was %.2f (anchor=edge %ld)\n", 3082 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0, 3083 edge1->pos / 64.0, edge - edges )); 3084 else 3085 FT_TRACE5(( " BLUE: edge %ld (opos=%.2f) snapped to %.2f," 3086 " was %.2f\n", 3087 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0, 3088 edge1->pos / 64.0 )); 3089 3090 num_actions++; 3091 #endif 3092 3093 edge1->pos = blue->fit; 3094 edge1->flags |= AF_EDGE_DONE; 3095 3096 if ( edge2 && !edge2->blue_edge ) 3097 { 3098 af_latin_align_linked_edge( hints, dim, edge1, edge2 ); 3099 edge2->flags |= AF_EDGE_DONE; 3100 3101 #ifdef FT_DEBUG_LEVEL_TRACE 3102 num_actions++; 3103 #endif 3104 } 3105 3106 if ( !anchor ) 3107 anchor = edge; 3108 } 3109 } 3110 3111 /* now we align all other stem edges, trying to maintain the */ 3112 /* relative order of stems in the glyph */ 3113 for ( edge = edges; edge < edge_limit; edge++ ) 3114 { 3115 AF_Edge edge2; 3116 3117 3118 if ( edge->flags & AF_EDGE_DONE ) 3119 continue; 3120 3121 /* skip all non-stem edges */ 3122 edge2 = edge->link; 3123 if ( !edge2 ) 3124 { 3125 has_serifs++; 3126 continue; 3127 } 3128 3129 /* now align the stem */ 3130 3131 /* this should not happen, but it's better to be safe */ 3132 if ( edge2->blue_edge ) 3133 { 3134 FT_TRACE5(( " ASSERTION FAILED for edge %ld\n", edge2 - edges )); 3135 3136 af_latin_align_linked_edge( hints, dim, edge2, edge ); 3137 edge->flags |= AF_EDGE_DONE; 3138 3139 #ifdef FT_DEBUG_LEVEL_TRACE 3140 num_actions++; 3141 #endif 3142 continue; 3143 } 3144 3145 if ( !anchor ) 3146 { 3147 /* if we reach this if clause, no stem has been aligned yet */ 3148 3149 FT_Pos org_len, org_center, cur_len; 3150 FT_Pos cur_pos1, error1, error2, u_off, d_off; 3151 3152 3153 org_len = edge2->opos - edge->opos; 3154 cur_len = af_latin_compute_stem_width( hints, dim, 3155 org_len, 0, 3156 edge->flags, 3157 edge2->flags ); 3158 3159 /* some voodoo to specially round edges for small stem widths; */ 3160 /* the idea is to align the center of a stem, then shifting */ 3161 /* the stem edges to suitable positions */ 3162 if ( cur_len <= 64 ) 3163 { 3164 /* width <= 1px */ 3165 u_off = 32; 3166 d_off = 32; 3167 } 3168 else 3169 { 3170 /* 1px < width < 1.5px */ 3171 u_off = 38; 3172 d_off = 26; 3173 } 3174 3175 if ( cur_len < 96 ) 3176 { 3177 org_center = edge->opos + ( org_len >> 1 ); 3178 cur_pos1 = FT_PIX_ROUND( org_center ); 3179 3180 error1 = org_center - ( cur_pos1 - u_off ); 3181 if ( error1 < 0 ) 3182 error1 = -error1; 3183 3184 error2 = org_center - ( cur_pos1 + d_off ); 3185 if ( error2 < 0 ) 3186 error2 = -error2; 3187 3188 if ( error1 < error2 ) 3189 cur_pos1 -= u_off; 3190 else 3191 cur_pos1 += d_off; 3192 3193 edge->pos = cur_pos1 - cur_len / 2; 3194 edge2->pos = edge->pos + cur_len; 3195 } 3196 else 3197 edge->pos = FT_PIX_ROUND( edge->opos ); 3198 3199 anchor = edge; 3200 edge->flags |= AF_EDGE_DONE; 3201 3202 FT_TRACE5(( " ANCHOR: edge %ld (opos=%.2f) and %ld (opos=%.2f)" 3203 " snapped to %.2f and %.2f\n", 3204 edge - edges, edge->opos / 64.0, 3205 edge2 - edges, edge2->opos / 64.0, 3206 edge->pos / 64.0, edge2->pos / 64.0 )); 3207 3208 af_latin_align_linked_edge( hints, dim, edge, edge2 ); 3209 3210 #ifdef FT_DEBUG_LEVEL_TRACE 3211 num_actions += 2; 3212 #endif 3213 } 3214 else 3215 { 3216 FT_Pos org_pos, org_len, org_center, cur_len; 3217 FT_Pos cur_pos1, cur_pos2, delta1, delta2; 3218 3219 3220 org_pos = anchor->pos + ( edge->opos - anchor->opos ); 3221 org_len = edge2->opos - edge->opos; 3222 org_center = org_pos + ( org_len >> 1 ); 3223 3224 cur_len = af_latin_compute_stem_width( hints, dim, 3225 org_len, 0, 3226 edge->flags, 3227 edge2->flags ); 3228 3229 if ( edge2->flags & AF_EDGE_DONE ) 3230 { 3231 FT_TRACE5(( " ADJUST: edge %ld (pos=%.2f) moved to %.2f\n", 3232 edge - edges, edge->pos / 64.0, 3233 ( edge2->pos - cur_len ) / 64.0 )); 3234 3235 edge->pos = edge2->pos - cur_len; 3236 } 3237 3238 else if ( cur_len < 96 ) 3239 { 3240 FT_Pos u_off, d_off; 3241 3242 3243 cur_pos1 = FT_PIX_ROUND( org_center ); 3244 3245 if ( cur_len <= 64 ) 3246 { 3247 u_off = 32; 3248 d_off = 32; 3249 } 3250 else 3251 { 3252 u_off = 38; 3253 d_off = 26; 3254 } 3255 3256 delta1 = org_center - ( cur_pos1 - u_off ); 3257 if ( delta1 < 0 ) 3258 delta1 = -delta1; 3259 3260 delta2 = org_center - ( cur_pos1 + d_off ); 3261 if ( delta2 < 0 ) 3262 delta2 = -delta2; 3263 3264 if ( delta1 < delta2 ) 3265 cur_pos1 -= u_off; 3266 else 3267 cur_pos1 += d_off; 3268 3269 edge->pos = cur_pos1 - cur_len / 2; 3270 edge2->pos = cur_pos1 + cur_len / 2; 3271 3272 FT_TRACE5(( " STEM: edge %ld (opos=%.2f) linked to %ld (opos=%.2f)" 3273 " snapped to %.2f and %.2f\n", 3274 edge - edges, edge->opos / 64.0, 3275 edge2 - edges, edge2->opos / 64.0, 3276 edge->pos / 64.0, edge2->pos / 64.0 )); 3277 } 3278 3279 else 3280 { 3281 org_pos = anchor->pos + ( edge->opos - anchor->opos ); 3282 org_len = edge2->opos - edge->opos; 3283 org_center = org_pos + ( org_len >> 1 ); 3284 3285 cur_len = af_latin_compute_stem_width( hints, dim, 3286 org_len, 0, 3287 edge->flags, 3288 edge2->flags ); 3289 3290 cur_pos1 = FT_PIX_ROUND( org_pos ); 3291 delta1 = cur_pos1 + ( cur_len >> 1 ) - org_center; 3292 if ( delta1 < 0 ) 3293 delta1 = -delta1; 3294 3295 cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len; 3296 delta2 = cur_pos2 + ( cur_len >> 1 ) - org_center; 3297 if ( delta2 < 0 ) 3298 delta2 = -delta2; 3299 3300 edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2; 3301 edge2->pos = edge->pos + cur_len; 3302 3303 FT_TRACE5(( " STEM: edge %ld (opos=%.2f) linked to %ld (opos=%.2f)" 3304 " snapped to %.2f and %.2f\n", 3305 edge - edges, edge->opos / 64.0, 3306 edge2 - edges, edge2->opos / 64.0, 3307 edge->pos / 64.0, edge2->pos / 64.0 )); 3308 } 3309 3310 #ifdef FT_DEBUG_LEVEL_TRACE 3311 num_actions++; 3312 #endif 3313 3314 edge->flags |= AF_EDGE_DONE; 3315 edge2->flags |= AF_EDGE_DONE; 3316 3317 if ( edge > edges && 3318 ( top_to_bottom_hinting ? ( edge->pos > edge[-1].pos ) 3319 : ( edge->pos < edge[-1].pos ) ) ) 3320 { 3321 /* don't move if stem would (almost) disappear otherwise; */ 3322 /* the ad-hoc value 16 corresponds to 1/4px */ 3323 if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 ) 3324 { 3325 #ifdef FT_DEBUG_LEVEL_TRACE 3326 FT_TRACE5(( " BOUND: edge %ld (pos=%.2f) moved to %.2f\n", 3327 edge - edges, 3328 edge->pos / 64.0, 3329 edge[-1].pos / 64.0 )); 3330 3331 num_actions++; 3332 #endif 3333 3334 edge->pos = edge[-1].pos; 3335 } 3336 } 3337 } 3338 } 3339 3340 /* make sure that lowercase m's maintain their symmetry */ 3341 3342 /* In general, lowercase m's have six vertical edges if they are sans */ 3343 /* serif, or twelve if they are with serifs. This implementation is */ 3344 /* based on that assumption, and seems to work very well with most */ 3345 /* faces. However, if for a certain face this assumption is not */ 3346 /* true, the m is just rendered like before. In addition, any stem */ 3347 /* correction will only be applied to symmetrical glyphs (even if the */ 3348 /* glyph is not an m), so the potential for unwanted distortion is */ 3349 /* relatively low. */ 3350 3351 /* We don't handle horizontal edges since we can't easily assure that */ 3352 /* the third (lowest) stem aligns with the base line; it might end up */ 3353 /* one pixel higher or lower. */ 3354 3355 n_edges = edge_limit - edges; 3356 if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) ) 3357 { 3358 AF_Edge edge1, edge2, edge3; 3359 FT_Pos dist1, dist2, span, delta; 3360 3361 3362 if ( n_edges == 6 ) 3363 { 3364 edge1 = edges; 3365 edge2 = edges + 2; 3366 edge3 = edges + 4; 3367 } 3368 else 3369 { 3370 edge1 = edges + 1; 3371 edge2 = edges + 5; 3372 edge3 = edges + 9; 3373 } 3374 3375 dist1 = edge2->opos - edge1->opos; 3376 dist2 = edge3->opos - edge2->opos; 3377 3378 span = dist1 - dist2; 3379 if ( span < 0 ) 3380 span = -span; 3381 3382 if ( span < 8 ) 3383 { 3384 delta = edge3->pos - ( 2 * edge2->pos - edge1->pos ); 3385 edge3->pos -= delta; 3386 if ( edge3->link ) 3387 edge3->link->pos -= delta; 3388 3389 /* move the serifs along with the stem */ 3390 if ( n_edges == 12 ) 3391 { 3392 ( edges + 8 )->pos -= delta; 3393 ( edges + 11 )->pos -= delta; 3394 } 3395 3396 edge3->flags |= AF_EDGE_DONE; 3397 if ( edge3->link ) 3398 edge3->link->flags |= AF_EDGE_DONE; 3399 } 3400 } 3401 3402 if ( has_serifs || !anchor ) 3403 { 3404 /* 3405 * now hint the remaining edges (serifs and single) in order 3406 * to complete our processing 3407 */ 3408 for ( edge = edges; edge < edge_limit; edge++ ) 3409 { 3410 FT_Pos delta; 3411 3412 3413 if ( edge->flags & AF_EDGE_DONE ) 3414 continue; 3415 3416 delta = 1000; 3417 3418 if ( edge->serif ) 3419 { 3420 delta = edge->serif->opos - edge->opos; 3421 if ( delta < 0 ) 3422 delta = -delta; 3423 } 3424 3425 if ( delta < 64 + 16 ) 3426 { 3427 af_latin_align_serif_edge( hints, edge->serif, edge ); 3428 FT_TRACE5(( " SERIF: edge %ld (opos=%.2f) serif to %ld (opos=%.2f)" 3429 " aligned to %.2f\n", 3430 edge - edges, edge->opos / 64.0, 3431 edge->serif - edges, edge->serif->opos / 64.0, 3432 edge->pos / 64.0 )); 3433 } 3434 else if ( !anchor ) 3435 { 3436 edge->pos = FT_PIX_ROUND( edge->opos ); 3437 anchor = edge; 3438 FT_TRACE5(( " SERIF_ANCHOR: edge %ld (opos=%.2f)" 3439 " snapped to %.2f\n", 3440 edge-edges, edge->opos / 64.0, edge->pos / 64.0 )); 3441 } 3442 else 3443 { 3444 AF_Edge before, after; 3445 3446 3447 for ( before = edge - 1; before >= edges; before-- ) 3448 if ( before->flags & AF_EDGE_DONE ) 3449 break; 3450 3451 for ( after = edge + 1; after < edge_limit; after++ ) 3452 if ( after->flags & AF_EDGE_DONE ) 3453 break; 3454 3455 if ( before >= edges && before < edge && 3456 after < edge_limit && after > edge ) 3457 { 3458 if ( after->opos == before->opos ) 3459 edge->pos = before->pos; 3460 else 3461 edge->pos = before->pos + 3462 FT_MulDiv( edge->opos - before->opos, 3463 after->pos - before->pos, 3464 after->opos - before->opos ); 3465 3466 FT_TRACE5(( " SERIF_LINK1: edge %ld (opos=%.2f) snapped to %.2f" 3467 " from %ld (opos=%.2f)\n", 3468 edge - edges, edge->opos / 64.0, 3469 edge->pos / 64.0, 3470 before - edges, before->opos / 64.0 )); 3471 } 3472 else 3473 { 3474 edge->pos = anchor->pos + 3475 ( ( edge->opos - anchor->opos + 16 ) & ~31 ); 3476 FT_TRACE5(( " SERIF_LINK2: edge %ld (opos=%.2f)" 3477 " snapped to %.2f\n", 3478 edge - edges, edge->opos / 64.0, edge->pos / 64.0 )); 3479 } 3480 } 3481 3482 #ifdef FT_DEBUG_LEVEL_TRACE 3483 num_actions++; 3484 #endif 3485 edge->flags |= AF_EDGE_DONE; 3486 3487 if ( edge > edges && 3488 ( top_to_bottom_hinting ? ( edge->pos > edge[-1].pos ) 3489 : ( edge->pos < edge[-1].pos ) ) ) 3490 { 3491 /* don't move if stem would (almost) disappear otherwise; */ 3492 /* the ad-hoc value 16 corresponds to 1/4px */ 3493 if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 ) 3494 { 3495 #ifdef FT_DEBUG_LEVEL_TRACE 3496 FT_TRACE5(( " BOUND: edge %ld (pos=%.2f) moved to %.2f\n", 3497 edge - edges, 3498 edge->pos / 64.0, 3499 edge[-1].pos / 64.0 )); 3500 3501 num_actions++; 3502 #endif 3503 edge->pos = edge[-1].pos; 3504 } 3505 } 3506 3507 if ( edge + 1 < edge_limit && 3508 edge[1].flags & AF_EDGE_DONE && 3509 ( top_to_bottom_hinting ? ( edge->pos < edge[1].pos ) 3510 : ( edge->pos > edge[1].pos ) ) ) 3511 { 3512 /* don't move if stem would (almost) disappear otherwise; */ 3513 /* the ad-hoc value 16 corresponds to 1/4px */ 3514 if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 ) 3515 { 3516 #ifdef FT_DEBUG_LEVEL_TRACE 3517 FT_TRACE5(( " BOUND: edge %ld (pos=%.2f) moved to %.2f\n", 3518 edge - edges, 3519 edge->pos / 64.0, 3520 edge[1].pos / 64.0 )); 3521 3522 num_actions++; 3523 #endif 3524 3525 edge->pos = edge[1].pos; 3526 } 3527 } 3528 } 3529 } 3530 3531 #ifdef FT_DEBUG_LEVEL_TRACE 3532 if ( !num_actions ) 3533 FT_TRACE5(( " (none)\n" )); 3534 FT_TRACE5(( "\n" )); 3535 #endif 3536 } 3537 3538 3539 /* Apply the complete hinting algorithm to a latin glyph. */ 3540 3541 static FT_Error af_latin_hints_apply(FT_UInt glyph_index,AF_GlyphHints hints,FT_Outline * outline,AF_LatinMetrics metrics)3542 af_latin_hints_apply( FT_UInt glyph_index, 3543 AF_GlyphHints hints, 3544 FT_Outline* outline, 3545 AF_LatinMetrics metrics ) 3546 { 3547 FT_Error error; 3548 int dim; 3549 3550 AF_LatinAxis axis; 3551 3552 3553 error = af_glyph_hints_reload( hints, outline ); 3554 if ( error ) 3555 goto Exit; 3556 3557 /* analyze glyph outline */ 3558 if ( AF_HINTS_DO_HORIZONTAL( hints ) ) 3559 { 3560 axis = &metrics->axis[AF_DIMENSION_HORZ]; 3561 error = af_latin_hints_detect_features( hints, 3562 axis->width_count, 3563 axis->widths, 3564 AF_DIMENSION_HORZ ); 3565 if ( error ) 3566 goto Exit; 3567 } 3568 3569 if ( AF_HINTS_DO_VERTICAL( hints ) ) 3570 { 3571 axis = &metrics->axis[AF_DIMENSION_VERT]; 3572 error = af_latin_hints_detect_features( hints, 3573 axis->width_count, 3574 axis->widths, 3575 AF_DIMENSION_VERT ); 3576 if ( error ) 3577 goto Exit; 3578 3579 /* apply blue zones to base characters only */ 3580 if ( !( metrics->root.globals->glyph_styles[glyph_index] & AF_NONBASE ) ) 3581 af_latin_hints_compute_blue_edges( hints, metrics ); 3582 } 3583 3584 /* grid-fit the outline */ 3585 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 3586 { 3587 if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) || 3588 ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) ) ) 3589 { 3590 af_latin_hint_edges( hints, (AF_Dimension)dim ); 3591 af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim ); 3592 af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim ); 3593 af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim ); 3594 } 3595 } 3596 3597 af_glyph_hints_save( hints, outline ); 3598 3599 Exit: 3600 return error; 3601 } 3602 3603 3604 /*************************************************************************/ 3605 /*************************************************************************/ 3606 /***** *****/ 3607 /***** L A T I N S C R I P T C L A S S *****/ 3608 /***** *****/ 3609 /*************************************************************************/ 3610 /*************************************************************************/ 3611 3612 3613 AF_DEFINE_WRITING_SYSTEM_CLASS( 3614 af_latin_writing_system_class, 3615 3616 AF_WRITING_SYSTEM_LATIN, 3617 3618 sizeof ( AF_LatinMetricsRec ), 3619 3620 (AF_WritingSystem_InitMetricsFunc) af_latin_metrics_init, /* style_metrics_init */ 3621 (AF_WritingSystem_ScaleMetricsFunc)af_latin_metrics_scale, /* style_metrics_scale */ 3622 (AF_WritingSystem_DoneMetricsFunc) NULL, /* style_metrics_done */ 3623 (AF_WritingSystem_GetStdWidthsFunc)af_latin_get_standard_widths, /* style_metrics_getstdw */ 3624 3625 (AF_WritingSystem_InitHintsFunc) af_latin_hints_init, /* style_hints_init */ 3626 (AF_WritingSystem_ApplyHintsFunc) af_latin_hints_apply /* style_hints_apply */ 3627 ) 3628 3629 3630 /* END */ 3631