1 /***************************************************************************/ 2 /* */ 3 /* aflatin.c */ 4 /* */ 5 /* Auto-fitter hinting routines for latin writing system (body). */ 6 /* */ 7 /* Copyright 2003-2014 by */ 8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ 9 /* */ 10 /* This file is part of the FreeType project, and may only be used, */ 11 /* modified, and distributed under the terms of the FreeType project */ 12 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 13 /* this file you indicate that you have read the license and */ 14 /* understand and accept it fully. */ 15 /* */ 16 /***************************************************************************/ 17 18 19 #include <ft2build.h> 20 #include FT_ADVANCES_H 21 #include FT_INTERNAL_DEBUG_H 22 23 #include "afglobal.h" 24 #include "afpic.h" 25 #include "aflatin.h" 26 #include "aferrors.h" 27 28 29 #ifdef AF_CONFIG_OPTION_USE_WARPER 30 #include "afwarp.h" 31 #endif 32 33 34 /*************************************************************************/ 35 /* */ 36 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ 37 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ 38 /* messages during execution. */ 39 /* */ 40 #undef FT_COMPONENT 41 #define FT_COMPONENT trace_aflatin 42 43 44 /*************************************************************************/ 45 /*************************************************************************/ 46 /***** *****/ 47 /***** L A T I N G L O B A L M E T R I C S *****/ 48 /***** *****/ 49 /*************************************************************************/ 50 /*************************************************************************/ 51 52 53 /* Find segments and links, compute all stem widths, and initialize */ 54 /* standard width and height for the glyph with given charcode. */ 55 56 FT_LOCAL_DEF( void ) af_latin_metrics_init_widths(AF_LatinMetrics metrics,FT_Face face)57 af_latin_metrics_init_widths( AF_LatinMetrics metrics, 58 FT_Face face ) 59 { 60 /* scan the array of segments in each direction */ 61 AF_GlyphHintsRec hints[1]; 62 63 64 FT_TRACE5(( "\n" 65 "latin standard widths computation (style `%s')\n" 66 "=====================================================\n" 67 "\n", 68 af_style_names[metrics->root.style_class->style] )); 69 70 af_glyph_hints_init( hints, face->memory ); 71 72 metrics->axis[AF_DIMENSION_HORZ].width_count = 0; 73 metrics->axis[AF_DIMENSION_VERT].width_count = 0; 74 75 { 76 FT_Error error; 77 FT_ULong glyph_index; 78 FT_Long y_offset; 79 int dim; 80 AF_LatinMetricsRec dummy[1]; 81 AF_Scaler scaler = &dummy->root.scaler; 82 83 #ifdef FT_CONFIG_OPTION_PIC 84 AF_FaceGlobals globals = metrics->root.globals; 85 #endif 86 87 AF_StyleClass style_class = metrics->root.style_class; 88 AF_ScriptClass script_class = AF_SCRIPT_CLASSES_GET 89 [style_class->script]; 90 91 FT_UInt32 standard_char; 92 93 94 /* 95 * We check more than a single standard character to catch features 96 * like `c2sc' (small caps from caps) that don't contain lowercase 97 * letters by definition, or other features that mainly operate on 98 * numerals. 99 */ 100 101 standard_char = script_class->standard_char1; 102 af_get_char_index( &metrics->root, 103 standard_char, 104 &glyph_index, 105 &y_offset ); 106 if ( !glyph_index ) 107 { 108 if ( script_class->standard_char2 ) 109 { 110 standard_char = script_class->standard_char2; 111 af_get_char_index( &metrics->root, 112 standard_char, 113 &glyph_index, 114 &y_offset ); 115 if ( !glyph_index ) 116 { 117 if ( script_class->standard_char3 ) 118 { 119 standard_char = script_class->standard_char3; 120 af_get_char_index( &metrics->root, 121 standard_char, 122 &glyph_index, 123 &y_offset ); 124 if ( !glyph_index ) 125 goto Exit; 126 } 127 else 128 goto Exit; 129 } 130 } 131 else 132 goto Exit; 133 } 134 135 FT_TRACE5(( "standard character: U+%04lX (glyph index %d)\n", 136 standard_char, glyph_index )); 137 138 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); 139 if ( error || face->glyph->outline.n_points <= 0 ) 140 goto Exit; 141 142 FT_ZERO( dummy ); 143 144 dummy->units_per_em = metrics->units_per_em; 145 146 scaler->x_scale = 0x10000L; 147 scaler->y_scale = 0x10000L; 148 scaler->x_delta = 0; 149 scaler->y_delta = 0; 150 151 scaler->face = face; 152 scaler->render_mode = FT_RENDER_MODE_NORMAL; 153 scaler->flags = 0; 154 155 af_glyph_hints_rescale( hints, (AF_StyleMetrics)dummy ); 156 157 error = af_glyph_hints_reload( hints, &face->glyph->outline ); 158 if ( error ) 159 goto Exit; 160 161 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 162 { 163 AF_LatinAxis axis = &metrics->axis[dim]; 164 AF_AxisHints axhints = &hints->axis[dim]; 165 AF_Segment seg, limit, link; 166 FT_UInt num_widths = 0; 167 168 169 error = af_latin_hints_compute_segments( hints, 170 (AF_Dimension)dim ); 171 if ( error ) 172 goto Exit; 173 174 af_latin_hints_link_segments( hints, 175 (AF_Dimension)dim ); 176 177 seg = axhints->segments; 178 limit = seg + axhints->num_segments; 179 180 for ( ; seg < limit; seg++ ) 181 { 182 link = seg->link; 183 184 /* we only consider stem segments there! */ 185 if ( link && link->link == seg && link > seg ) 186 { 187 FT_Pos dist; 188 189 190 dist = seg->pos - link->pos; 191 if ( dist < 0 ) 192 dist = -dist; 193 194 if ( num_widths < AF_LATIN_MAX_WIDTHS ) 195 axis->widths[num_widths++].org = dist; 196 } 197 } 198 199 /* this also replaces multiple almost identical stem widths */ 200 /* with a single one (the value 100 is heuristic) */ 201 af_sort_and_quantize_widths( &num_widths, axis->widths, 202 dummy->units_per_em / 100 ); 203 axis->width_count = num_widths; 204 } 205 206 Exit: 207 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 208 { 209 AF_LatinAxis axis = &metrics->axis[dim]; 210 FT_Pos stdw; 211 212 213 stdw = ( axis->width_count > 0 ) ? axis->widths[0].org 214 : AF_LATIN_CONSTANT( metrics, 50 ); 215 216 /* let's try 20% of the smallest width */ 217 axis->edge_distance_threshold = stdw / 5; 218 axis->standard_width = stdw; 219 axis->extra_light = 0; 220 221 #ifdef FT_DEBUG_LEVEL_TRACE 222 { 223 FT_UInt i; 224 225 226 FT_TRACE5(( "%s widths:\n", 227 dim == AF_DIMENSION_VERT ? "horizontal" 228 : "vertical" )); 229 230 FT_TRACE5(( " %d (standard)", axis->standard_width )); 231 for ( i = 1; i < axis->width_count; i++ ) 232 FT_TRACE5(( " %d", axis->widths[i].org )); 233 234 FT_TRACE5(( "\n" )); 235 } 236 #endif 237 } 238 } 239 240 FT_TRACE5(( "\n" )); 241 242 af_glyph_hints_done( hints ); 243 } 244 245 246 /* Find all blue zones. Flat segments give the reference points, */ 247 /* round segments the overshoot positions. */ 248 249 static void af_latin_metrics_init_blues(AF_LatinMetrics metrics,FT_Face face)250 af_latin_metrics_init_blues( AF_LatinMetrics metrics, 251 FT_Face face ) 252 { 253 FT_Pos flats [AF_BLUE_STRING_MAX_LEN]; 254 FT_Pos rounds[AF_BLUE_STRING_MAX_LEN]; 255 256 FT_Int num_flats; 257 FT_Int num_rounds; 258 259 AF_LatinBlue blue; 260 FT_Error error; 261 AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT]; 262 FT_Outline outline; 263 264 AF_StyleClass sc = metrics->root.style_class; 265 266 AF_Blue_Stringset bss = sc->blue_stringset; 267 const AF_Blue_StringRec* bs = &af_blue_stringsets[bss]; 268 269 270 /* we walk over the blue character strings as specified in the */ 271 /* style's entry in the `af_blue_stringset' array */ 272 273 FT_TRACE5(( "latin blue zones computation\n" 274 "============================\n" 275 "\n" )); 276 277 for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ ) 278 { 279 const char* p = &af_blue_strings[bs->string]; 280 FT_Pos* blue_ref; 281 FT_Pos* blue_shoot; 282 283 284 #ifdef FT_DEBUG_LEVEL_TRACE 285 { 286 FT_Bool have_flag = 0; 287 288 289 FT_TRACE5(( "blue zone %d", axis->blue_count )); 290 291 if ( bs->properties ) 292 { 293 FT_TRACE5(( " (" )); 294 295 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 296 { 297 FT_TRACE5(( "top" )); 298 have_flag = 1; 299 } 300 301 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) 302 { 303 if ( have_flag ) 304 FT_TRACE5(( ", " )); 305 FT_TRACE5(( "small top" )); 306 have_flag = 1; 307 } 308 309 if ( AF_LATIN_IS_LONG_BLUE( bs ) ) 310 { 311 if ( have_flag ) 312 FT_TRACE5(( ", " )); 313 FT_TRACE5(( "long" )); 314 } 315 316 FT_TRACE5(( ")" )); 317 } 318 319 FT_TRACE5(( ":\n" )); 320 } 321 #endif /* FT_DEBUG_LEVEL_TRACE */ 322 323 num_flats = 0; 324 num_rounds = 0; 325 326 while ( *p ) 327 { 328 FT_ULong ch; 329 FT_ULong glyph_index; 330 FT_Long y_offset; 331 FT_Pos best_y; /* same as points.y */ 332 FT_Int best_point, best_contour_first, best_contour_last; 333 FT_Vector* points; 334 FT_Bool round = 0; 335 336 337 GET_UTF8_CHAR( ch, p ); 338 339 /* load the character in the face -- skip unknown or empty ones */ 340 af_get_char_index( &metrics->root, ch, &glyph_index, &y_offset ); 341 if ( glyph_index == 0 ) 342 { 343 FT_TRACE5(( " U+%04lX unavailable\n", ch )); 344 continue; 345 } 346 347 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); 348 outline = face->glyph->outline; 349 if ( error || outline.n_points <= 0 ) 350 { 351 FT_TRACE5(( " U+%04lX contains no outlines\n", ch )); 352 continue; 353 } 354 355 /* now compute min or max point indices and coordinates */ 356 points = outline.points; 357 best_point = -1; 358 best_y = 0; /* make compiler happy */ 359 best_contour_first = 0; /* ditto */ 360 best_contour_last = 0; /* ditto */ 361 362 { 363 FT_Int nn; 364 FT_Int first = 0; 365 FT_Int last = -1; 366 367 368 for ( nn = 0; nn < outline.n_contours; first = last + 1, nn++ ) 369 { 370 FT_Int old_best_point = best_point; 371 FT_Int pp; 372 373 374 last = outline.contours[nn]; 375 376 /* Avoid single-point contours since they are never rasterized. */ 377 /* In some fonts, they correspond to mark attachment points */ 378 /* that are way outside of the glyph's real outline. */ 379 if ( last <= first ) 380 continue; 381 382 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 383 { 384 for ( pp = first; pp <= last; pp++ ) 385 if ( best_point < 0 || points[pp].y > best_y ) 386 { 387 best_point = pp; 388 best_y = points[pp].y; 389 } 390 } 391 else 392 { 393 for ( pp = first; pp <= last; pp++ ) 394 if ( best_point < 0 || points[pp].y < best_y ) 395 { 396 best_point = pp; 397 best_y = points[pp].y; 398 } 399 } 400 401 if ( best_point != old_best_point ) 402 { 403 best_contour_first = first; 404 best_contour_last = last; 405 } 406 } 407 } 408 409 /* now check whether the point belongs to a straight or round */ 410 /* segment; we first need to find in which contour the extremum */ 411 /* lies, then inspect its previous and next points */ 412 if ( best_point >= 0 ) 413 { 414 FT_Pos best_x = points[best_point].x; 415 FT_Int prev, next; 416 FT_Int best_segment_first, best_segment_last; 417 FT_Int best_on_point_first, best_on_point_last; 418 FT_Pos dist; 419 420 421 best_segment_first = best_point; 422 best_segment_last = best_point; 423 424 if ( FT_CURVE_TAG( outline.tags[best_point] ) == FT_CURVE_TAG_ON ) 425 { 426 best_on_point_first = best_point; 427 best_on_point_last = best_point; 428 } 429 else 430 { 431 best_on_point_first = -1; 432 best_on_point_last = -1; 433 } 434 435 /* look for the previous and next points on the contour */ 436 /* that are not on the same Y coordinate, then threshold */ 437 /* the `closeness'... */ 438 prev = best_point; 439 next = prev; 440 441 do 442 { 443 if ( prev > best_contour_first ) 444 prev--; 445 else 446 prev = best_contour_last; 447 448 dist = FT_ABS( points[prev].y - best_y ); 449 /* accept a small distance or a small angle (both values are */ 450 /* heuristic; value 20 corresponds to approx. 2.9 degrees) */ 451 if ( dist > 5 ) 452 if ( FT_ABS( points[prev].x - best_x ) <= 20 * dist ) 453 break; 454 455 best_segment_first = prev; 456 457 if ( FT_CURVE_TAG( outline.tags[prev] ) == FT_CURVE_TAG_ON ) 458 { 459 best_on_point_first = prev; 460 if ( best_on_point_last < 0 ) 461 best_on_point_last = prev; 462 } 463 464 } while ( prev != best_point ); 465 466 do 467 { 468 if ( next < best_contour_last ) 469 next++; 470 else 471 next = best_contour_first; 472 473 dist = FT_ABS( points[next].y - best_y ); 474 if ( dist > 5 ) 475 if ( FT_ABS( points[next].x - best_x ) <= 20 * dist ) 476 break; 477 478 best_segment_last = next; 479 480 if ( FT_CURVE_TAG( outline.tags[next] ) == FT_CURVE_TAG_ON ) 481 { 482 best_on_point_last = next; 483 if ( best_on_point_first < 0 ) 484 best_on_point_first = next; 485 } 486 487 } while ( next != best_point ); 488 489 if ( AF_LATIN_IS_LONG_BLUE( bs ) ) 490 { 491 /* If this flag is set, we have an additional constraint to */ 492 /* get the blue zone distance: Find a segment of the topmost */ 493 /* (or bottommost) contour that is longer than a heuristic */ 494 /* threshold. This ensures that small bumps in the outline */ 495 /* are ignored (for example, the `vertical serifs' found in */ 496 /* many Hebrew glyph designs). */ 497 498 /* If this segment is long enough, we are done. Otherwise, */ 499 /* search the segment next to the extremum that is long */ 500 /* enough, has the same direction, and a not too large */ 501 /* vertical distance from the extremum. Note that the */ 502 /* algorithm doesn't check whether the found segment is */ 503 /* actually the one (vertically) nearest to the extremum. */ 504 505 /* heuristic threshold value */ 506 FT_Pos length_threshold = metrics->units_per_em / 25; 507 508 509 dist = FT_ABS( points[best_segment_last].x - 510 points[best_segment_first].x ); 511 512 if ( dist < length_threshold && 513 best_segment_last - best_segment_first + 2 <= 514 best_contour_last - best_contour_first ) 515 { 516 /* heuristic threshold value */ 517 FT_Pos height_threshold = metrics->units_per_em / 4; 518 519 FT_Int first; 520 FT_Int last; 521 FT_Bool hit; 522 523 FT_Bool left2right; 524 525 526 /* compute direction */ 527 prev = best_point; 528 529 do 530 { 531 if ( prev > best_contour_first ) 532 prev--; 533 else 534 prev = best_contour_last; 535 536 if ( points[prev].x != best_x ) 537 break; 538 539 } while ( prev != best_point ); 540 541 /* skip glyph for the degenerate case */ 542 if ( prev == best_point ) 543 continue; 544 545 left2right = FT_BOOL( points[prev].x < points[best_point].x ); 546 547 first = best_segment_last; 548 last = first; 549 hit = 0; 550 551 do 552 { 553 FT_Bool l2r; 554 FT_Pos d; 555 FT_Int p_first, p_last; 556 557 558 if ( !hit ) 559 { 560 /* no hit; adjust first point */ 561 first = last; 562 563 /* also adjust first and last on point */ 564 if ( FT_CURVE_TAG( outline.tags[first] ) == 565 FT_CURVE_TAG_ON ) 566 { 567 p_first = first; 568 p_last = first; 569 } 570 else 571 { 572 p_first = -1; 573 p_last = -1; 574 } 575 576 hit = 1; 577 } 578 579 if ( last < best_contour_last ) 580 last++; 581 else 582 last = best_contour_first; 583 584 if ( FT_ABS( best_y - points[first].y ) > height_threshold ) 585 { 586 /* vertical distance too large */ 587 hit = 0; 588 continue; 589 } 590 591 /* same test as above */ 592 dist = FT_ABS( points[last].y - points[first].y ); 593 if ( dist > 5 ) 594 if ( FT_ABS( points[last].x - points[first].x ) <= 595 20 * dist ) 596 { 597 hit = 0; 598 continue; 599 } 600 601 if ( FT_CURVE_TAG( outline.tags[last] ) == FT_CURVE_TAG_ON ) 602 { 603 p_last = last; 604 if ( p_first < 0 ) 605 p_first = last; 606 } 607 608 l2r = FT_BOOL( points[first].x < points[last].x ); 609 d = FT_ABS( points[last].x - points[first].x ); 610 611 if ( l2r == left2right && 612 d >= length_threshold ) 613 { 614 /* all constraints are met; update segment after finding */ 615 /* its end */ 616 do 617 { 618 if ( last < best_contour_last ) 619 last++; 620 else 621 last = best_contour_first; 622 623 d = FT_ABS( points[last].y - points[first].y ); 624 if ( d > 5 ) 625 if ( FT_ABS( points[next].x - points[first].x ) <= 626 20 * dist ) 627 { 628 if ( last > best_contour_first ) 629 last--; 630 else 631 last = best_contour_last; 632 break; 633 } 634 635 p_last = last; 636 637 if ( FT_CURVE_TAG( outline.tags[last] ) == 638 FT_CURVE_TAG_ON ) 639 { 640 p_last = last; 641 if ( p_first < 0 ) 642 p_first = last; 643 } 644 645 } while ( last != best_segment_first ); 646 647 best_y = points[first].y; 648 649 best_segment_first = first; 650 best_segment_last = last; 651 652 best_on_point_first = p_first; 653 best_on_point_last = p_last; 654 655 break; 656 } 657 658 } while ( last != best_segment_first ); 659 } 660 } 661 662 /* for computing blue zones, we add the y offset as returned */ 663 /* by the currently used OpenType feature -- for example, */ 664 /* superscript glyphs might be identical to subscript glyphs */ 665 /* with a vertical shift */ 666 best_y += y_offset; 667 668 FT_TRACE5(( " U+%04lX: best_y = %5ld", ch, best_y )); 669 670 /* now set the `round' flag depending on the segment's kind: */ 671 /* */ 672 /* - if the horizontal distance between the first and last */ 673 /* `on' point is larger than upem/8 (value 8 is heuristic) */ 674 /* we have a flat segment */ 675 /* - if either the first or the last point of the segment is */ 676 /* an `off' point, the segment is round, otherwise it is */ 677 /* flat */ 678 if ( best_on_point_first >= 0 && 679 best_on_point_last >= 0 && 680 (FT_UInt)( FT_ABS( points[best_on_point_last].x - 681 points[best_on_point_first].x ) ) > 682 metrics->units_per_em / 8 ) 683 round = 0; 684 else 685 round = FT_BOOL( 686 FT_CURVE_TAG( outline.tags[best_segment_first] ) != 687 FT_CURVE_TAG_ON || 688 FT_CURVE_TAG( outline.tags[best_segment_last] ) != 689 FT_CURVE_TAG_ON ); 690 691 FT_TRACE5(( " (%s)\n", round ? "round" : "flat" )); 692 } 693 694 if ( round ) 695 rounds[num_rounds++] = best_y; 696 else 697 flats[num_flats++] = best_y; 698 } 699 700 if ( num_flats == 0 && num_rounds == 0 ) 701 { 702 /* 703 * we couldn't find a single glyph to compute this blue zone, 704 * we will simply ignore it then 705 */ 706 FT_TRACE5(( " empty\n" )); 707 continue; 708 } 709 710 /* we have computed the contents of the `rounds' and `flats' tables, */ 711 /* now determine the reference and overshoot position of the blue -- */ 712 /* we simply take the median value after a simple sort */ 713 af_sort_pos( num_rounds, rounds ); 714 af_sort_pos( num_flats, flats ); 715 716 blue = &axis->blues[axis->blue_count]; 717 blue_ref = &blue->ref.org; 718 blue_shoot = &blue->shoot.org; 719 720 axis->blue_count++; 721 722 if ( num_flats == 0 ) 723 { 724 *blue_ref = 725 *blue_shoot = rounds[num_rounds / 2]; 726 } 727 else if ( num_rounds == 0 ) 728 { 729 *blue_ref = 730 *blue_shoot = flats[num_flats / 2]; 731 } 732 else 733 { 734 *blue_ref = flats [num_flats / 2]; 735 *blue_shoot = rounds[num_rounds / 2]; 736 } 737 738 /* there are sometimes problems: if the overshoot position of top */ 739 /* zones is under its reference position, or the opposite for bottom */ 740 /* zones. We must thus check everything there and correct the errors */ 741 if ( *blue_shoot != *blue_ref ) 742 { 743 FT_Pos ref = *blue_ref; 744 FT_Pos shoot = *blue_shoot; 745 FT_Bool over_ref = FT_BOOL( shoot > ref ); 746 747 748 if ( AF_LATIN_IS_TOP_BLUE( bs ) ^ over_ref ) 749 { 750 *blue_ref = 751 *blue_shoot = ( shoot + ref ) / 2; 752 753 FT_TRACE5(( " [overshoot smaller than reference," 754 " taking mean value]\n" )); 755 } 756 } 757 758 blue->flags = 0; 759 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 760 blue->flags |= AF_LATIN_BLUE_TOP; 761 762 /* 763 * The following flag is used later to adjust the y and x scales 764 * in order to optimize the pixel grid alignment of the top of small 765 * letters. 766 */ 767 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) 768 blue->flags |= AF_LATIN_BLUE_ADJUSTMENT; 769 770 FT_TRACE5(( " -> reference = %ld\n" 771 " overshoot = %ld\n", 772 *blue_ref, *blue_shoot )); 773 } 774 775 FT_TRACE5(( "\n" )); 776 777 return; 778 } 779 780 781 /* Check whether all ASCII digits have the same advance width. */ 782 783 FT_LOCAL_DEF( void ) af_latin_metrics_check_digits(AF_LatinMetrics metrics,FT_Face face)784 af_latin_metrics_check_digits( AF_LatinMetrics metrics, 785 FT_Face face ) 786 { 787 FT_UInt i; 788 FT_Bool started = 0, same_width = 1; 789 FT_Fixed advance, old_advance = 0; 790 791 792 /* digit `0' is 0x30 in all supported charmaps */ 793 for ( i = 0x30; i <= 0x39; i++ ) 794 { 795 FT_ULong glyph_index; 796 FT_Long y_offset; 797 798 799 af_get_char_index( &metrics->root, i, &glyph_index, &y_offset ); 800 if ( glyph_index == 0 ) 801 continue; 802 803 if ( FT_Get_Advance( face, glyph_index, 804 FT_LOAD_NO_SCALE | 805 FT_LOAD_NO_HINTING | 806 FT_LOAD_IGNORE_TRANSFORM, 807 &advance ) ) 808 continue; 809 810 if ( started ) 811 { 812 if ( advance != old_advance ) 813 { 814 same_width = 0; 815 break; 816 } 817 } 818 else 819 { 820 old_advance = advance; 821 started = 1; 822 } 823 } 824 825 metrics->root.digits_have_same_width = same_width; 826 } 827 828 829 /* Initialize global metrics. */ 830 831 FT_LOCAL_DEF( FT_Error ) af_latin_metrics_init(AF_LatinMetrics metrics,FT_Face face)832 af_latin_metrics_init( AF_LatinMetrics metrics, 833 FT_Face face ) 834 { 835 FT_CharMap oldmap = face->charmap; 836 837 838 metrics->units_per_em = face->units_per_EM; 839 840 if ( !FT_Select_Charmap( face, FT_ENCODING_UNICODE ) ) 841 { 842 af_latin_metrics_init_widths( metrics, face ); 843 af_latin_metrics_init_blues( metrics, face ); 844 af_latin_metrics_check_digits( metrics, face ); 845 } 846 847 FT_Set_Charmap( face, oldmap ); 848 return FT_Err_Ok; 849 } 850 851 852 /* Adjust scaling value, then scale and shift widths */ 853 /* and blue zones (if applicable) for given dimension. */ 854 855 static void af_latin_metrics_scale_dim(AF_LatinMetrics metrics,AF_Scaler scaler,AF_Dimension dim)856 af_latin_metrics_scale_dim( AF_LatinMetrics metrics, 857 AF_Scaler scaler, 858 AF_Dimension dim ) 859 { 860 FT_Fixed scale; 861 FT_Pos delta; 862 AF_LatinAxis axis; 863 FT_UInt nn; 864 865 866 if ( dim == AF_DIMENSION_HORZ ) 867 { 868 scale = scaler->x_scale; 869 delta = scaler->x_delta; 870 } 871 else 872 { 873 scale = scaler->y_scale; 874 delta = scaler->y_delta; 875 } 876 877 axis = &metrics->axis[dim]; 878 879 if ( axis->org_scale == scale && axis->org_delta == delta ) 880 return; 881 882 axis->org_scale = scale; 883 axis->org_delta = delta; 884 885 /* 886 * correct X and Y scale to optimize the alignment of the top of small 887 * letters to the pixel grid 888 */ 889 { 890 AF_LatinAxis Axis = &metrics->axis[AF_DIMENSION_VERT]; 891 AF_LatinBlue blue = NULL; 892 893 894 for ( nn = 0; nn < Axis->blue_count; nn++ ) 895 { 896 if ( Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT ) 897 { 898 blue = &Axis->blues[nn]; 899 break; 900 } 901 } 902 903 if ( blue ) 904 { 905 FT_Pos scaled; 906 FT_Pos threshold; 907 FT_Pos fitted; 908 FT_UInt limit; 909 FT_UInt ppem; 910 911 912 scaled = FT_MulFix( blue->shoot.org, scaler->y_scale ); 913 ppem = metrics->root.scaler.face->size->metrics.x_ppem; 914 limit = metrics->root.globals->increase_x_height; 915 threshold = 40; 916 917 /* if the `increase-x-height' property is active, */ 918 /* we round up much more often */ 919 if ( limit && 920 ppem <= limit && 921 ppem >= AF_PROP_INCREASE_X_HEIGHT_MIN ) 922 threshold = 52; 923 924 fitted = ( scaled + threshold ) & ~63; 925 926 if ( scaled != fitted ) 927 { 928 #if 0 929 if ( dim == AF_DIMENSION_HORZ ) 930 { 931 if ( fitted < scaled ) 932 scale -= scale / 50; /* scale *= 0.98 */ 933 } 934 else 935 #endif 936 if ( dim == AF_DIMENSION_VERT ) 937 { 938 scale = FT_MulDiv( scale, fitted, scaled ); 939 940 FT_TRACE5(( 941 "af_latin_metrics_scale_dim:" 942 " x height alignment (style `%s'):\n" 943 " " 944 " vertical scaling changed from %.4f to %.4f (by %d%%)\n" 945 "\n", 946 af_style_names[metrics->root.style_class->style], 947 axis->org_scale / 65536.0, 948 scale / 65536.0, 949 ( fitted - scaled ) * 100 / scaled )); 950 } 951 } 952 } 953 } 954 955 axis->scale = scale; 956 axis->delta = delta; 957 958 if ( dim == AF_DIMENSION_HORZ ) 959 { 960 metrics->root.scaler.x_scale = scale; 961 metrics->root.scaler.x_delta = delta; 962 } 963 else 964 { 965 metrics->root.scaler.y_scale = scale; 966 metrics->root.scaler.y_delta = delta; 967 } 968 969 FT_TRACE5(( "%s widths (style `%s')\n", 970 dim == AF_DIMENSION_HORZ ? "horizontal" : "vertical", 971 af_style_names[metrics->root.style_class->style] )); 972 973 /* scale the widths */ 974 for ( nn = 0; nn < axis->width_count; nn++ ) 975 { 976 AF_Width width = axis->widths + nn; 977 978 979 width->cur = FT_MulFix( width->org, scale ); 980 width->fit = width->cur; 981 982 FT_TRACE5(( " %d scaled to %.2f\n", 983 width->org, 984 width->cur / 64.0 )); 985 } 986 987 FT_TRACE5(( "\n" )); 988 989 /* an extra-light axis corresponds to a standard width that is */ 990 /* smaller than 5/8 pixels */ 991 axis->extra_light = 992 (FT_Bool)( FT_MulFix( axis->standard_width, scale ) < 32 + 8 ); 993 994 #ifdef FT_DEBUG_LEVEL_TRACE 995 if ( axis->extra_light ) 996 FT_TRACE5(( "`%s' style is extra light (at current resolution)\n" 997 "\n", 998 af_style_names[metrics->root.style_class->style] )); 999 #endif 1000 1001 if ( dim == AF_DIMENSION_VERT ) 1002 { 1003 FT_TRACE5(( "blue zones (style `%s')\n", 1004 af_style_names[metrics->root.style_class->style] )); 1005 1006 /* scale the blue zones */ 1007 for ( nn = 0; nn < axis->blue_count; nn++ ) 1008 { 1009 AF_LatinBlue blue = &axis->blues[nn]; 1010 FT_Pos dist; 1011 1012 1013 blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta; 1014 blue->ref.fit = blue->ref.cur; 1015 blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta; 1016 blue->shoot.fit = blue->shoot.cur; 1017 blue->flags &= ~AF_LATIN_BLUE_ACTIVE; 1018 1019 /* a blue zone is only active if it is less than 3/4 pixels tall */ 1020 dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale ); 1021 if ( dist <= 48 && dist >= -48 ) 1022 { 1023 #if 0 1024 FT_Pos delta1; 1025 #endif 1026 FT_Pos delta2; 1027 1028 1029 /* use discrete values for blue zone widths */ 1030 1031 #if 0 1032 1033 /* generic, original code */ 1034 delta1 = blue->shoot.org - blue->ref.org; 1035 delta2 = delta1; 1036 if ( delta1 < 0 ) 1037 delta2 = -delta2; 1038 1039 delta2 = FT_MulFix( delta2, scale ); 1040 1041 if ( delta2 < 32 ) 1042 delta2 = 0; 1043 else if ( delta2 < 64 ) 1044 delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 ); 1045 else 1046 delta2 = FT_PIX_ROUND( delta2 ); 1047 1048 if ( delta1 < 0 ) 1049 delta2 = -delta2; 1050 1051 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); 1052 blue->shoot.fit = blue->ref.fit + delta2; 1053 1054 #else 1055 1056 /* simplified version due to abs(dist) <= 48 */ 1057 delta2 = dist; 1058 if ( dist < 0 ) 1059 delta2 = -delta2; 1060 1061 if ( delta2 < 32 ) 1062 delta2 = 0; 1063 else if ( delta2 < 48 ) 1064 delta2 = 32; 1065 else 1066 delta2 = 64; 1067 1068 if ( dist < 0 ) 1069 delta2 = -delta2; 1070 1071 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); 1072 blue->shoot.fit = blue->ref.fit - delta2; 1073 1074 #endif 1075 1076 blue->flags |= AF_LATIN_BLUE_ACTIVE; 1077 1078 FT_TRACE5(( " reference %d: %d scaled to %.2f%s\n" 1079 " overshoot %d: %d scaled to %.2f%s\n", 1080 nn, 1081 blue->ref.org, 1082 blue->ref.fit / 64.0, 1083 blue->flags & AF_LATIN_BLUE_ACTIVE ? "" 1084 : " (inactive)", 1085 nn, 1086 blue->shoot.org, 1087 blue->shoot.fit / 64.0, 1088 blue->flags & AF_LATIN_BLUE_ACTIVE ? "" 1089 : " (inactive)" )); 1090 } 1091 } 1092 } 1093 } 1094 1095 1096 /* Scale global values in both directions. */ 1097 1098 FT_LOCAL_DEF( void ) af_latin_metrics_scale(AF_LatinMetrics metrics,AF_Scaler scaler)1099 af_latin_metrics_scale( AF_LatinMetrics metrics, 1100 AF_Scaler scaler ) 1101 { 1102 metrics->root.scaler.render_mode = scaler->render_mode; 1103 metrics->root.scaler.face = scaler->face; 1104 metrics->root.scaler.flags = scaler->flags; 1105 1106 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ ); 1107 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT ); 1108 } 1109 1110 1111 /*************************************************************************/ 1112 /*************************************************************************/ 1113 /***** *****/ 1114 /***** L A T I N G L Y P H A N A L Y S I S *****/ 1115 /***** *****/ 1116 /*************************************************************************/ 1117 /*************************************************************************/ 1118 1119 1120 /* Walk over all contours and compute its segments. */ 1121 1122 FT_LOCAL_DEF( FT_Error ) af_latin_hints_compute_segments(AF_GlyphHints hints,AF_Dimension dim)1123 af_latin_hints_compute_segments( AF_GlyphHints hints, 1124 AF_Dimension dim ) 1125 { 1126 AF_AxisHints axis = &hints->axis[dim]; 1127 FT_Memory memory = hints->memory; 1128 FT_Error error = FT_Err_Ok; 1129 AF_Segment segment = NULL; 1130 AF_SegmentRec seg0; 1131 AF_Point* contour = hints->contours; 1132 AF_Point* contour_limit = contour + hints->num_contours; 1133 AF_Direction major_dir, segment_dir; 1134 1135 1136 FT_ZERO( &seg0 ); 1137 seg0.score = 32000; 1138 seg0.flags = AF_EDGE_NORMAL; 1139 1140 major_dir = (AF_Direction)FT_ABS( axis->major_dir ); 1141 segment_dir = major_dir; 1142 1143 axis->num_segments = 0; 1144 1145 /* set up (u,v) in each point */ 1146 if ( dim == AF_DIMENSION_HORZ ) 1147 { 1148 AF_Point point = hints->points; 1149 AF_Point limit = point + hints->num_points; 1150 1151 1152 for ( ; point < limit; point++ ) 1153 { 1154 point->u = point->fx; 1155 point->v = point->fy; 1156 } 1157 } 1158 else 1159 { 1160 AF_Point point = hints->points; 1161 AF_Point limit = point + hints->num_points; 1162 1163 1164 for ( ; point < limit; point++ ) 1165 { 1166 point->u = point->fy; 1167 point->v = point->fx; 1168 } 1169 } 1170 1171 /* do each contour separately */ 1172 for ( ; contour < contour_limit; contour++ ) 1173 { 1174 AF_Point point = contour[0]; 1175 AF_Point last = point->prev; 1176 int on_edge = 0; 1177 FT_Pos min_pos = 32000; /* minimum segment pos != min_coord */ 1178 FT_Pos max_pos = -32000; /* maximum segment pos != max_coord */ 1179 FT_Bool passed; 1180 1181 1182 if ( point == last ) /* skip singletons -- just in case */ 1183 continue; 1184 1185 if ( FT_ABS( last->out_dir ) == major_dir && 1186 FT_ABS( point->out_dir ) == major_dir ) 1187 { 1188 /* we are already on an edge, try to locate its start */ 1189 last = point; 1190 1191 for (;;) 1192 { 1193 point = point->prev; 1194 if ( FT_ABS( point->out_dir ) != major_dir ) 1195 { 1196 point = point->next; 1197 break; 1198 } 1199 if ( point == last ) 1200 break; 1201 } 1202 } 1203 1204 last = point; 1205 passed = 0; 1206 1207 for (;;) 1208 { 1209 FT_Pos u, v; 1210 1211 1212 if ( on_edge ) 1213 { 1214 u = point->u; 1215 if ( u < min_pos ) 1216 min_pos = u; 1217 if ( u > max_pos ) 1218 max_pos = u; 1219 1220 if ( point->out_dir != segment_dir || point == last ) 1221 { 1222 /* we are just leaving an edge; record a new segment! */ 1223 segment->last = point; 1224 segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); 1225 1226 /* a segment is round if either its first or last point */ 1227 /* is a control point */ 1228 if ( ( segment->first->flags | point->flags ) & 1229 AF_FLAG_CONTROL ) 1230 segment->flags |= AF_EDGE_ROUND; 1231 1232 /* compute segment size */ 1233 min_pos = max_pos = point->v; 1234 1235 v = segment->first->v; 1236 if ( v < min_pos ) 1237 min_pos = v; 1238 if ( v > max_pos ) 1239 max_pos = v; 1240 1241 segment->min_coord = (FT_Short)min_pos; 1242 segment->max_coord = (FT_Short)max_pos; 1243 segment->height = (FT_Short)( segment->max_coord - 1244 segment->min_coord ); 1245 1246 on_edge = 0; 1247 segment = NULL; 1248 /* fall through */ 1249 } 1250 } 1251 1252 /* now exit if we are at the start/end point */ 1253 if ( point == last ) 1254 { 1255 if ( passed ) 1256 break; 1257 passed = 1; 1258 } 1259 1260 if ( !on_edge && FT_ABS( point->out_dir ) == major_dir ) 1261 { 1262 /* this is the start of a new segment! */ 1263 segment_dir = (AF_Direction)point->out_dir; 1264 1265 /* clear all segment fields */ 1266 error = af_axis_hints_new_segment( axis, memory, &segment ); 1267 if ( error ) 1268 goto Exit; 1269 1270 segment[0] = seg0; 1271 segment->dir = (FT_Char)segment_dir; 1272 min_pos = max_pos = point->u; 1273 segment->first = point; 1274 segment->last = point; 1275 on_edge = 1; 1276 } 1277 1278 point = point->next; 1279 } 1280 1281 } /* contours */ 1282 1283 1284 /* now slightly increase the height of segments if this makes */ 1285 /* sense -- this is used to better detect and ignore serifs */ 1286 { 1287 AF_Segment segments = axis->segments; 1288 AF_Segment segments_end = segments + axis->num_segments; 1289 1290 1291 for ( segment = segments; segment < segments_end; segment++ ) 1292 { 1293 AF_Point first = segment->first; 1294 AF_Point last = segment->last; 1295 FT_Pos first_v = first->v; 1296 FT_Pos last_v = last->v; 1297 1298 1299 if ( first == last ) 1300 continue; 1301 1302 if ( first_v < last_v ) 1303 { 1304 AF_Point p; 1305 1306 1307 p = first->prev; 1308 if ( p->v < first_v ) 1309 segment->height = (FT_Short)( segment->height + 1310 ( ( first_v - p->v ) >> 1 ) ); 1311 1312 p = last->next; 1313 if ( p->v > last_v ) 1314 segment->height = (FT_Short)( segment->height + 1315 ( ( p->v - last_v ) >> 1 ) ); 1316 } 1317 else 1318 { 1319 AF_Point p; 1320 1321 1322 p = first->prev; 1323 if ( p->v > first_v ) 1324 segment->height = (FT_Short)( segment->height + 1325 ( ( p->v - first_v ) >> 1 ) ); 1326 1327 p = last->next; 1328 if ( p->v < last_v ) 1329 segment->height = (FT_Short)( segment->height + 1330 ( ( last_v - p->v ) >> 1 ) ); 1331 } 1332 } 1333 } 1334 1335 Exit: 1336 return error; 1337 } 1338 1339 1340 /* Link segments to form stems and serifs. */ 1341 1342 FT_LOCAL_DEF( void ) af_latin_hints_link_segments(AF_GlyphHints hints,AF_Dimension dim)1343 af_latin_hints_link_segments( AF_GlyphHints hints, 1344 AF_Dimension dim ) 1345 { 1346 AF_AxisHints axis = &hints->axis[dim]; 1347 AF_Segment segments = axis->segments; 1348 AF_Segment segment_limit = segments + axis->num_segments; 1349 FT_Pos len_threshold, len_score; 1350 AF_Segment seg1, seg2; 1351 1352 1353 len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 ); 1354 if ( len_threshold == 0 ) 1355 len_threshold = 1; 1356 1357 len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 ); 1358 1359 /* now compare each segment to the others */ 1360 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 1361 { 1362 /* the fake segments are introduced to hint the metrics -- */ 1363 /* we must never link them to anything */ 1364 if ( seg1->dir != axis->major_dir || seg1->first == seg1->last ) 1365 continue; 1366 1367 /* search for stems having opposite directions, */ 1368 /* with seg1 to the `left' of seg2 */ 1369 for ( seg2 = segments; seg2 < segment_limit; seg2++ ) 1370 { 1371 FT_Pos pos1 = seg1->pos; 1372 FT_Pos pos2 = seg2->pos; 1373 1374 1375 if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 ) 1376 { 1377 /* compute distance between the two segments */ 1378 FT_Pos dist = pos2 - pos1; 1379 FT_Pos min = seg1->min_coord; 1380 FT_Pos max = seg1->max_coord; 1381 FT_Pos len, score; 1382 1383 1384 if ( min < seg2->min_coord ) 1385 min = seg2->min_coord; 1386 1387 if ( max > seg2->max_coord ) 1388 max = seg2->max_coord; 1389 1390 /* compute maximum coordinate difference of the two segments */ 1391 len = max - min; 1392 if ( len >= len_threshold ) 1393 { 1394 /* small coordinate differences cause a higher score, and */ 1395 /* segments with a greater distance cause a higher score also */ 1396 score = dist + len_score / len; 1397 1398 /* and we search for the smallest score */ 1399 /* of the sum of the two values */ 1400 if ( score < seg1->score ) 1401 { 1402 seg1->score = score; 1403 seg1->link = seg2; 1404 } 1405 1406 if ( score < seg2->score ) 1407 { 1408 seg2->score = score; 1409 seg2->link = seg1; 1410 } 1411 } 1412 } 1413 } 1414 } 1415 1416 /* now compute the `serif' segments, cf. explanations in `afhints.h' */ 1417 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 1418 { 1419 seg2 = seg1->link; 1420 1421 if ( seg2 ) 1422 { 1423 if ( seg2->link != seg1 ) 1424 { 1425 seg1->link = 0; 1426 seg1->serif = seg2->link; 1427 } 1428 } 1429 } 1430 } 1431 1432 1433 /* Link segments to edges, using feature analysis for selection. */ 1434 1435 FT_LOCAL_DEF( FT_Error ) af_latin_hints_compute_edges(AF_GlyphHints hints,AF_Dimension dim)1436 af_latin_hints_compute_edges( AF_GlyphHints hints, 1437 AF_Dimension dim ) 1438 { 1439 AF_AxisHints axis = &hints->axis[dim]; 1440 FT_Error error = FT_Err_Ok; 1441 FT_Memory memory = hints->memory; 1442 AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim]; 1443 1444 AF_Segment segments = axis->segments; 1445 AF_Segment segment_limit = segments + axis->num_segments; 1446 AF_Segment seg; 1447 1448 #if 0 1449 AF_Direction up_dir; 1450 #endif 1451 FT_Fixed scale; 1452 FT_Pos edge_distance_threshold; 1453 FT_Pos segment_length_threshold; 1454 1455 1456 axis->num_edges = 0; 1457 1458 scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale 1459 : hints->y_scale; 1460 1461 #if 0 1462 up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP 1463 : AF_DIR_RIGHT; 1464 #endif 1465 1466 /* 1467 * We ignore all segments that are less than 1 pixel in length 1468 * to avoid many problems with serif fonts. We compute the 1469 * corresponding threshold in font units. 1470 */ 1471 if ( dim == AF_DIMENSION_HORZ ) 1472 segment_length_threshold = FT_DivFix( 64, hints->y_scale ); 1473 else 1474 segment_length_threshold = 0; 1475 1476 /*********************************************************************/ 1477 /* */ 1478 /* We begin by generating a sorted table of edges for the current */ 1479 /* direction. To do so, we simply scan each segment and try to find */ 1480 /* an edge in our table that corresponds to its position. */ 1481 /* */ 1482 /* If no edge is found, we create and insert a new edge in the */ 1483 /* sorted table. Otherwise, we simply add the segment to the edge's */ 1484 /* list which gets processed in the second step to compute the */ 1485 /* edge's properties. */ 1486 /* */ 1487 /* Note that the table of edges is sorted along the segment/edge */ 1488 /* position. */ 1489 /* */ 1490 /*********************************************************************/ 1491 1492 /* assure that edge distance threshold is at most 0.25px */ 1493 edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold, 1494 scale ); 1495 if ( edge_distance_threshold > 64 / 4 ) 1496 edge_distance_threshold = 64 / 4; 1497 1498 edge_distance_threshold = FT_DivFix( edge_distance_threshold, 1499 scale ); 1500 1501 for ( seg = segments; seg < segment_limit; seg++ ) 1502 { 1503 AF_Edge found = NULL; 1504 FT_Int ee; 1505 1506 1507 if ( seg->height < segment_length_threshold ) 1508 continue; 1509 1510 /* A special case for serif edges: If they are smaller than */ 1511 /* 1.5 pixels we ignore them. */ 1512 if ( seg->serif && 1513 2 * seg->height < 3 * segment_length_threshold ) 1514 continue; 1515 1516 /* look for an edge corresponding to the segment */ 1517 for ( ee = 0; ee < axis->num_edges; ee++ ) 1518 { 1519 AF_Edge edge = axis->edges + ee; 1520 FT_Pos dist; 1521 1522 1523 dist = seg->pos - edge->fpos; 1524 if ( dist < 0 ) 1525 dist = -dist; 1526 1527 if ( dist < edge_distance_threshold && edge->dir == seg->dir ) 1528 { 1529 found = edge; 1530 break; 1531 } 1532 } 1533 1534 if ( !found ) 1535 { 1536 AF_Edge edge; 1537 1538 1539 /* insert a new edge in the list and */ 1540 /* sort according to the position */ 1541 error = af_axis_hints_new_edge( axis, seg->pos, 1542 (AF_Direction)seg->dir, 1543 memory, &edge ); 1544 if ( error ) 1545 goto Exit; 1546 1547 /* add the segment to the new edge's list */ 1548 FT_ZERO( edge ); 1549 1550 edge->first = seg; 1551 edge->last = seg; 1552 edge->dir = seg->dir; 1553 edge->fpos = seg->pos; 1554 edge->opos = FT_MulFix( seg->pos, scale ); 1555 edge->pos = edge->opos; 1556 seg->edge_next = seg; 1557 } 1558 else 1559 { 1560 /* if an edge was found, simply add the segment to the edge's */ 1561 /* list */ 1562 seg->edge_next = found->first; 1563 found->last->edge_next = seg; 1564 found->last = seg; 1565 } 1566 } 1567 1568 1569 /******************************************************************/ 1570 /* */ 1571 /* Good, we now compute each edge's properties according to the */ 1572 /* segments found on its position. Basically, these are */ 1573 /* */ 1574 /* - the edge's main direction */ 1575 /* - stem edge, serif edge or both (which defaults to stem then) */ 1576 /* - rounded edge, straight or both (which defaults to straight) */ 1577 /* - link for edge */ 1578 /* */ 1579 /******************************************************************/ 1580 1581 /* first of all, set the `edge' field in each segment -- this is */ 1582 /* required in order to compute edge links */ 1583 1584 /* 1585 * Note that removing this loop and setting the `edge' field of each 1586 * segment directly in the code above slows down execution speed for 1587 * some reasons on platforms like the Sun. 1588 */ 1589 { 1590 AF_Edge edges = axis->edges; 1591 AF_Edge edge_limit = edges + axis->num_edges; 1592 AF_Edge edge; 1593 1594 1595 for ( edge = edges; edge < edge_limit; edge++ ) 1596 { 1597 seg = edge->first; 1598 if ( seg ) 1599 do 1600 { 1601 seg->edge = edge; 1602 seg = seg->edge_next; 1603 1604 } while ( seg != edge->first ); 1605 } 1606 1607 /* now compute each edge properties */ 1608 for ( edge = edges; edge < edge_limit; edge++ ) 1609 { 1610 FT_Int is_round = 0; /* does it contain round segments? */ 1611 FT_Int is_straight = 0; /* does it contain straight segments? */ 1612 #if 0 1613 FT_Pos ups = 0; /* number of upwards segments */ 1614 FT_Pos downs = 0; /* number of downwards segments */ 1615 #endif 1616 1617 1618 seg = edge->first; 1619 1620 do 1621 { 1622 FT_Bool is_serif; 1623 1624 1625 /* check for roundness of segment */ 1626 if ( seg->flags & AF_EDGE_ROUND ) 1627 is_round++; 1628 else 1629 is_straight++; 1630 1631 #if 0 1632 /* check for segment direction */ 1633 if ( seg->dir == up_dir ) 1634 ups += seg->max_coord - seg->min_coord; 1635 else 1636 downs += seg->max_coord - seg->min_coord; 1637 #endif 1638 1639 /* check for links -- if seg->serif is set, then seg->link must */ 1640 /* be ignored */ 1641 is_serif = (FT_Bool)( seg->serif && 1642 seg->serif->edge && 1643 seg->serif->edge != edge ); 1644 1645 if ( ( seg->link && seg->link->edge != NULL ) || is_serif ) 1646 { 1647 AF_Edge edge2; 1648 AF_Segment seg2; 1649 1650 1651 edge2 = edge->link; 1652 seg2 = seg->link; 1653 1654 if ( is_serif ) 1655 { 1656 seg2 = seg->serif; 1657 edge2 = edge->serif; 1658 } 1659 1660 if ( edge2 ) 1661 { 1662 FT_Pos edge_delta; 1663 FT_Pos seg_delta; 1664 1665 1666 edge_delta = edge->fpos - edge2->fpos; 1667 if ( edge_delta < 0 ) 1668 edge_delta = -edge_delta; 1669 1670 seg_delta = seg->pos - seg2->pos; 1671 if ( seg_delta < 0 ) 1672 seg_delta = -seg_delta; 1673 1674 if ( seg_delta < edge_delta ) 1675 edge2 = seg2->edge; 1676 } 1677 else 1678 edge2 = seg2->edge; 1679 1680 if ( is_serif ) 1681 { 1682 edge->serif = edge2; 1683 edge2->flags |= AF_EDGE_SERIF; 1684 } 1685 else 1686 edge->link = edge2; 1687 } 1688 1689 seg = seg->edge_next; 1690 1691 } while ( seg != edge->first ); 1692 1693 /* set the round/straight flags */ 1694 edge->flags = AF_EDGE_NORMAL; 1695 1696 if ( is_round > 0 && is_round >= is_straight ) 1697 edge->flags |= AF_EDGE_ROUND; 1698 1699 #if 0 1700 /* set the edge's main direction */ 1701 edge->dir = AF_DIR_NONE; 1702 1703 if ( ups > downs ) 1704 edge->dir = (FT_Char)up_dir; 1705 1706 else if ( ups < downs ) 1707 edge->dir = (FT_Char)-up_dir; 1708 1709 else if ( ups == downs ) 1710 edge->dir = 0; /* both up and down! */ 1711 #endif 1712 1713 /* get rid of serifs if link is set */ 1714 /* XXX: This gets rid of many unpleasant artefacts! */ 1715 /* Example: the `c' in cour.pfa at size 13 */ 1716 1717 if ( edge->serif && edge->link ) 1718 edge->serif = 0; 1719 } 1720 } 1721 1722 Exit: 1723 return error; 1724 } 1725 1726 1727 /* Detect segments and edges for given dimension. */ 1728 1729 FT_LOCAL_DEF( FT_Error ) af_latin_hints_detect_features(AF_GlyphHints hints,AF_Dimension dim)1730 af_latin_hints_detect_features( AF_GlyphHints hints, 1731 AF_Dimension dim ) 1732 { 1733 FT_Error error; 1734 1735 1736 error = af_latin_hints_compute_segments( hints, dim ); 1737 if ( !error ) 1738 { 1739 af_latin_hints_link_segments( hints, dim ); 1740 1741 error = af_latin_hints_compute_edges( hints, dim ); 1742 } 1743 1744 return error; 1745 } 1746 1747 1748 /* Compute all edges which lie within blue zones. */ 1749 1750 FT_LOCAL_DEF( void ) af_latin_hints_compute_blue_edges(AF_GlyphHints hints,AF_LatinMetrics metrics)1751 af_latin_hints_compute_blue_edges( AF_GlyphHints hints, 1752 AF_LatinMetrics metrics ) 1753 { 1754 AF_AxisHints axis = &hints->axis[AF_DIMENSION_VERT]; 1755 AF_Edge edge = axis->edges; 1756 AF_Edge edge_limit = edge + axis->num_edges; 1757 AF_LatinAxis latin = &metrics->axis[AF_DIMENSION_VERT]; 1758 FT_Fixed scale = latin->scale; 1759 1760 1761 /* compute which blue zones are active, i.e. have their scaled */ 1762 /* size < 3/4 pixels */ 1763 1764 /* for each horizontal edge search the blue zone which is closest */ 1765 for ( ; edge < edge_limit; edge++ ) 1766 { 1767 FT_UInt bb; 1768 AF_Width best_blue = NULL; 1769 FT_Pos best_dist; /* initial threshold */ 1770 1771 1772 /* compute the initial threshold as a fraction of the EM size */ 1773 /* (the value 40 is heuristic) */ 1774 best_dist = FT_MulFix( metrics->units_per_em / 40, scale ); 1775 1776 /* assure a minimum distance of 0.5px */ 1777 if ( best_dist > 64 / 2 ) 1778 best_dist = 64 / 2; 1779 1780 for ( bb = 0; bb < latin->blue_count; bb++ ) 1781 { 1782 AF_LatinBlue blue = latin->blues + bb; 1783 FT_Bool is_top_blue, is_major_dir; 1784 1785 1786 /* skip inactive blue zones (i.e., those that are too large) */ 1787 if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) 1788 continue; 1789 1790 /* if it is a top zone, check for right edges -- if it is a bottom */ 1791 /* zone, check for left edges */ 1792 /* */ 1793 /* of course, that's for TrueType */ 1794 is_top_blue = (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_TOP ) != 0 ); 1795 is_major_dir = FT_BOOL( edge->dir == axis->major_dir ); 1796 1797 /* if it is a top zone, the edge must be against the major */ 1798 /* direction; if it is a bottom zone, it must be in the major */ 1799 /* direction */ 1800 if ( is_top_blue ^ is_major_dir ) 1801 { 1802 FT_Pos dist; 1803 1804 1805 /* first of all, compare it to the reference position */ 1806 dist = edge->fpos - blue->ref.org; 1807 if ( dist < 0 ) 1808 dist = -dist; 1809 1810 dist = FT_MulFix( dist, scale ); 1811 if ( dist < best_dist ) 1812 { 1813 best_dist = dist; 1814 best_blue = &blue->ref; 1815 } 1816 1817 /* now compare it to the overshoot position and check whether */ 1818 /* the edge is rounded, and whether the edge is over the */ 1819 /* reference position of a top zone, or under the reference */ 1820 /* position of a bottom zone */ 1821 if ( edge->flags & AF_EDGE_ROUND && dist != 0 ) 1822 { 1823 FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org ); 1824 1825 1826 if ( is_top_blue ^ is_under_ref ) 1827 { 1828 dist = edge->fpos - blue->shoot.org; 1829 if ( dist < 0 ) 1830 dist = -dist; 1831 1832 dist = FT_MulFix( dist, scale ); 1833 if ( dist < best_dist ) 1834 { 1835 best_dist = dist; 1836 best_blue = &blue->shoot; 1837 } 1838 } 1839 } 1840 } 1841 } 1842 1843 if ( best_blue ) 1844 edge->blue_edge = best_blue; 1845 } 1846 } 1847 1848 1849 /* Initalize hinting engine. */ 1850 1851 static FT_Error af_latin_hints_init(AF_GlyphHints hints,AF_LatinMetrics metrics)1852 af_latin_hints_init( AF_GlyphHints hints, 1853 AF_LatinMetrics metrics ) 1854 { 1855 FT_Render_Mode mode; 1856 FT_UInt32 scaler_flags, other_flags; 1857 FT_Face face = metrics->root.scaler.face; 1858 1859 1860 af_glyph_hints_rescale( hints, (AF_StyleMetrics)metrics ); 1861 1862 /* 1863 * correct x_scale and y_scale if needed, since they may have 1864 * been modified by `af_latin_metrics_scale_dim' above 1865 */ 1866 hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale; 1867 hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta; 1868 hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale; 1869 hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta; 1870 1871 /* compute flags depending on render mode, etc. */ 1872 mode = metrics->root.scaler.render_mode; 1873 1874 #if 0 /* #ifdef AF_CONFIG_OPTION_USE_WARPER */ 1875 if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V ) 1876 metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL; 1877 #endif 1878 1879 scaler_flags = hints->scaler_flags; 1880 other_flags = 0; 1881 1882 /* 1883 * We snap the width of vertical stems for the monochrome and 1884 * horizontal LCD rendering targets only. 1885 */ 1886 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD ) 1887 other_flags |= AF_LATIN_HINTS_HORZ_SNAP; 1888 1889 /* 1890 * We snap the width of horizontal stems for the monochrome and 1891 * vertical LCD rendering targets only. 1892 */ 1893 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V ) 1894 other_flags |= AF_LATIN_HINTS_VERT_SNAP; 1895 1896 /* 1897 * We adjust stems to full pixels only if we don't use the `light' mode. 1898 */ 1899 if ( mode != FT_RENDER_MODE_LIGHT ) 1900 other_flags |= AF_LATIN_HINTS_STEM_ADJUST; 1901 1902 if ( mode == FT_RENDER_MODE_MONO ) 1903 other_flags |= AF_LATIN_HINTS_MONO; 1904 1905 /* 1906 * In `light' hinting mode we disable horizontal hinting completely. 1907 * We also do it if the face is italic. 1908 */ 1909 if ( mode == FT_RENDER_MODE_LIGHT || 1910 ( face->style_flags & FT_STYLE_FLAG_ITALIC ) != 0 ) 1911 scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL; 1912 1913 hints->scaler_flags = scaler_flags; 1914 hints->other_flags = other_flags; 1915 1916 return FT_Err_Ok; 1917 } 1918 1919 1920 /*************************************************************************/ 1921 /*************************************************************************/ 1922 /***** *****/ 1923 /***** L A T I N G L Y P H G R I D - F I T T I N G *****/ 1924 /***** *****/ 1925 /*************************************************************************/ 1926 /*************************************************************************/ 1927 1928 /* Snap a given width in scaled coordinates to one of the */ 1929 /* current standard widths. */ 1930 1931 static FT_Pos af_latin_snap_width(AF_Width widths,FT_Int count,FT_Pos width)1932 af_latin_snap_width( AF_Width widths, 1933 FT_Int count, 1934 FT_Pos width ) 1935 { 1936 int n; 1937 FT_Pos best = 64 + 32 + 2; 1938 FT_Pos reference = width; 1939 FT_Pos scaled; 1940 1941 1942 for ( n = 0; n < count; n++ ) 1943 { 1944 FT_Pos w; 1945 FT_Pos dist; 1946 1947 1948 w = widths[n].cur; 1949 dist = width - w; 1950 if ( dist < 0 ) 1951 dist = -dist; 1952 if ( dist < best ) 1953 { 1954 best = dist; 1955 reference = w; 1956 } 1957 } 1958 1959 scaled = FT_PIX_ROUND( reference ); 1960 1961 if ( width >= reference ) 1962 { 1963 if ( width < scaled + 48 ) 1964 width = reference; 1965 } 1966 else 1967 { 1968 if ( width > scaled - 48 ) 1969 width = reference; 1970 } 1971 1972 return width; 1973 } 1974 1975 1976 /* Compute the snapped width of a given stem, ignoring very thin ones. */ 1977 /* There is a lot of voodoo in this function; changing the hard-coded */ 1978 /* parameters influence the whole hinting process. */ 1979 1980 static FT_Pos af_latin_compute_stem_width(AF_GlyphHints hints,AF_Dimension dim,FT_Pos width,AF_Edge_Flags base_flags,AF_Edge_Flags stem_flags)1981 af_latin_compute_stem_width( AF_GlyphHints hints, 1982 AF_Dimension dim, 1983 FT_Pos width, 1984 AF_Edge_Flags base_flags, 1985 AF_Edge_Flags stem_flags ) 1986 { 1987 AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics; 1988 AF_LatinAxis axis = &metrics->axis[dim]; 1989 FT_Pos dist = width; 1990 FT_Int sign = 0; 1991 FT_Int vertical = ( dim == AF_DIMENSION_VERT ); 1992 1993 1994 if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) || 1995 axis->extra_light ) 1996 return width; 1997 1998 if ( dist < 0 ) 1999 { 2000 dist = -width; 2001 sign = 1; 2002 } 2003 2004 if ( ( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) || 2005 ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) ) 2006 { 2007 /* smooth hinting process: very lightly quantize the stem width */ 2008 2009 /* leave the widths of serifs alone */ 2010 if ( ( stem_flags & AF_EDGE_SERIF ) && 2011 vertical && 2012 ( dist < 3 * 64 ) ) 2013 goto Done_Width; 2014 2015 else if ( base_flags & AF_EDGE_ROUND ) 2016 { 2017 if ( dist < 80 ) 2018 dist = 64; 2019 } 2020 else if ( dist < 56 ) 2021 dist = 56; 2022 2023 if ( axis->width_count > 0 ) 2024 { 2025 FT_Pos delta; 2026 2027 2028 /* compare to standard width */ 2029 delta = dist - axis->widths[0].cur; 2030 2031 if ( delta < 0 ) 2032 delta = -delta; 2033 2034 if ( delta < 40 ) 2035 { 2036 dist = axis->widths[0].cur; 2037 if ( dist < 48 ) 2038 dist = 48; 2039 2040 goto Done_Width; 2041 } 2042 2043 if ( dist < 3 * 64 ) 2044 { 2045 delta = dist & 63; 2046 dist &= -64; 2047 2048 if ( delta < 10 ) 2049 dist += delta; 2050 2051 else if ( delta < 32 ) 2052 dist += 10; 2053 2054 else if ( delta < 54 ) 2055 dist += 54; 2056 2057 else 2058 dist += delta; 2059 } 2060 else 2061 dist = ( dist + 32 ) & ~63; 2062 } 2063 } 2064 else 2065 { 2066 /* strong hinting process: snap the stem width to integer pixels */ 2067 2068 FT_Pos org_dist = dist; 2069 2070 2071 dist = af_latin_snap_width( axis->widths, axis->width_count, dist ); 2072 2073 if ( vertical ) 2074 { 2075 /* in the case of vertical hinting, always round */ 2076 /* the stem heights to integer pixels */ 2077 2078 if ( dist >= 64 ) 2079 dist = ( dist + 16 ) & ~63; 2080 else 2081 dist = 64; 2082 } 2083 else 2084 { 2085 if ( AF_LATIN_HINTS_DO_MONO( hints ) ) 2086 { 2087 /* monochrome horizontal hinting: snap widths to integer pixels */ 2088 /* with a different threshold */ 2089 2090 if ( dist < 64 ) 2091 dist = 64; 2092 else 2093 dist = ( dist + 32 ) & ~63; 2094 } 2095 else 2096 { 2097 /* for horizontal anti-aliased hinting, we adopt a more subtle */ 2098 /* approach: we strengthen small stems, round stems whose size */ 2099 /* is between 1 and 2 pixels to an integer, otherwise nothing */ 2100 2101 if ( dist < 48 ) 2102 dist = ( dist + 64 ) >> 1; 2103 2104 else if ( dist < 128 ) 2105 { 2106 /* We only round to an integer width if the corresponding */ 2107 /* distortion is less than 1/4 pixel. Otherwise this */ 2108 /* makes everything worse since the diagonals, which are */ 2109 /* not hinted, appear a lot bolder or thinner than the */ 2110 /* vertical stems. */ 2111 2112 FT_Pos delta; 2113 2114 2115 dist = ( dist + 22 ) & ~63; 2116 delta = dist - org_dist; 2117 if ( delta < 0 ) 2118 delta = -delta; 2119 2120 if ( delta >= 16 ) 2121 { 2122 dist = org_dist; 2123 if ( dist < 48 ) 2124 dist = ( dist + 64 ) >> 1; 2125 } 2126 } 2127 else 2128 /* round otherwise to prevent color fringes in LCD mode */ 2129 dist = ( dist + 32 ) & ~63; 2130 } 2131 } 2132 } 2133 2134 Done_Width: 2135 if ( sign ) 2136 dist = -dist; 2137 2138 return dist; 2139 } 2140 2141 2142 /* Align one stem edge relative to the previous stem edge. */ 2143 2144 static void af_latin_align_linked_edge(AF_GlyphHints hints,AF_Dimension dim,AF_Edge base_edge,AF_Edge stem_edge)2145 af_latin_align_linked_edge( AF_GlyphHints hints, 2146 AF_Dimension dim, 2147 AF_Edge base_edge, 2148 AF_Edge stem_edge ) 2149 { 2150 FT_Pos dist = stem_edge->opos - base_edge->opos; 2151 2152 FT_Pos fitted_width = af_latin_compute_stem_width( 2153 hints, dim, dist, 2154 (AF_Edge_Flags)base_edge->flags, 2155 (AF_Edge_Flags)stem_edge->flags ); 2156 2157 2158 stem_edge->pos = base_edge->pos + fitted_width; 2159 2160 FT_TRACE5(( " LINK: edge %d (opos=%.2f) linked to %.2f," 2161 " dist was %.2f, now %.2f\n", 2162 stem_edge-hints->axis[dim].edges, stem_edge->opos / 64.0, 2163 stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 )); 2164 } 2165 2166 2167 /* Shift the coordinates of the `serif' edge by the same amount */ 2168 /* as the corresponding `base' edge has been moved already. */ 2169 2170 static void af_latin_align_serif_edge(AF_GlyphHints hints,AF_Edge base,AF_Edge serif)2171 af_latin_align_serif_edge( AF_GlyphHints hints, 2172 AF_Edge base, 2173 AF_Edge serif ) 2174 { 2175 FT_UNUSED( hints ); 2176 2177 serif->pos = base->pos + ( serif->opos - base->opos ); 2178 } 2179 2180 2181 /*************************************************************************/ 2182 /*************************************************************************/ 2183 /*************************************************************************/ 2184 /**** ****/ 2185 /**** E D G E H I N T I N G ****/ 2186 /**** ****/ 2187 /*************************************************************************/ 2188 /*************************************************************************/ 2189 /*************************************************************************/ 2190 2191 2192 /* The main grid-fitting routine. */ 2193 2194 FT_LOCAL_DEF( void ) af_latin_hint_edges(AF_GlyphHints hints,AF_Dimension dim)2195 af_latin_hint_edges( AF_GlyphHints hints, 2196 AF_Dimension dim ) 2197 { 2198 AF_AxisHints axis = &hints->axis[dim]; 2199 AF_Edge edges = axis->edges; 2200 AF_Edge edge_limit = edges + axis->num_edges; 2201 FT_PtrDist n_edges; 2202 AF_Edge edge; 2203 AF_Edge anchor = NULL; 2204 FT_Int has_serifs = 0; 2205 2206 #ifdef FT_DEBUG_LEVEL_TRACE 2207 FT_UInt num_actions = 0; 2208 #endif 2209 2210 2211 FT_TRACE5(( "latin %s edge hinting (style `%s')\n", 2212 dim == AF_DIMENSION_VERT ? "horizontal" : "vertical", 2213 af_style_names[hints->metrics->style_class->style] )); 2214 2215 /* we begin by aligning all stems relative to the blue zone */ 2216 /* if needed -- that's only for horizontal edges */ 2217 2218 if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) ) 2219 { 2220 for ( edge = edges; edge < edge_limit; edge++ ) 2221 { 2222 AF_Width blue; 2223 AF_Edge edge1, edge2; /* these edges form the stem to check */ 2224 2225 2226 if ( edge->flags & AF_EDGE_DONE ) 2227 continue; 2228 2229 blue = edge->blue_edge; 2230 edge1 = NULL; 2231 edge2 = edge->link; 2232 2233 if ( blue ) 2234 edge1 = edge; 2235 2236 /* flip edges if the other stem is aligned to a blue zone */ 2237 else if ( edge2 && edge2->blue_edge ) 2238 { 2239 blue = edge2->blue_edge; 2240 edge1 = edge2; 2241 edge2 = edge; 2242 } 2243 2244 if ( !edge1 ) 2245 continue; 2246 2247 #ifdef FT_DEBUG_LEVEL_TRACE 2248 if ( !anchor ) 2249 FT_TRACE5(( " BLUE_ANCHOR: edge %d (opos=%.2f) snapped to %.2f," 2250 " was %.2f (anchor=edge %d)\n", 2251 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0, 2252 edge1->pos / 64.0, edge - edges )); 2253 else 2254 FT_TRACE5(( " BLUE: edge %d (opos=%.2f) snapped to %.2f," 2255 " was %.2f\n", 2256 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0, 2257 edge1->pos / 64.0 )); 2258 2259 num_actions++; 2260 #endif 2261 2262 edge1->pos = blue->fit; 2263 edge1->flags |= AF_EDGE_DONE; 2264 2265 if ( edge2 && !edge2->blue_edge ) 2266 { 2267 af_latin_align_linked_edge( hints, dim, edge1, edge2 ); 2268 edge2->flags |= AF_EDGE_DONE; 2269 2270 #ifdef FT_DEBUG_LEVEL_TRACE 2271 num_actions++; 2272 #endif 2273 } 2274 2275 if ( !anchor ) 2276 anchor = edge; 2277 } 2278 } 2279 2280 /* now we align all other stem edges, trying to maintain the */ 2281 /* relative order of stems in the glyph */ 2282 for ( edge = edges; edge < edge_limit; edge++ ) 2283 { 2284 AF_Edge edge2; 2285 2286 2287 if ( edge->flags & AF_EDGE_DONE ) 2288 continue; 2289 2290 /* skip all non-stem edges */ 2291 edge2 = edge->link; 2292 if ( !edge2 ) 2293 { 2294 has_serifs++; 2295 continue; 2296 } 2297 2298 /* now align the stem */ 2299 2300 /* this should not happen, but it's better to be safe */ 2301 if ( edge2->blue_edge ) 2302 { 2303 FT_TRACE5(( " ASSERTION FAILED for edge %d\n", edge2-edges )); 2304 2305 af_latin_align_linked_edge( hints, dim, edge2, edge ); 2306 edge->flags |= AF_EDGE_DONE; 2307 2308 #ifdef FT_DEBUG_LEVEL_TRACE 2309 num_actions++; 2310 #endif 2311 continue; 2312 } 2313 2314 if ( !anchor ) 2315 { 2316 /* if we reach this if clause, no stem has been aligned yet */ 2317 2318 FT_Pos org_len, org_center, cur_len; 2319 FT_Pos cur_pos1, error1, error2, u_off, d_off; 2320 2321 2322 org_len = edge2->opos - edge->opos; 2323 cur_len = af_latin_compute_stem_width( 2324 hints, dim, org_len, 2325 (AF_Edge_Flags)edge->flags, 2326 (AF_Edge_Flags)edge2->flags ); 2327 2328 /* some voodoo to specially round edges for small stem widths; */ 2329 /* the idea is to align the center of a stem, then shifting */ 2330 /* the stem edges to suitable positions */ 2331 if ( cur_len <= 64 ) 2332 { 2333 /* width <= 1px */ 2334 u_off = 32; 2335 d_off = 32; 2336 } 2337 else 2338 { 2339 /* 1px < width < 1.5px */ 2340 u_off = 38; 2341 d_off = 26; 2342 } 2343 2344 if ( cur_len < 96 ) 2345 { 2346 org_center = edge->opos + ( org_len >> 1 ); 2347 cur_pos1 = FT_PIX_ROUND( org_center ); 2348 2349 error1 = org_center - ( cur_pos1 - u_off ); 2350 if ( error1 < 0 ) 2351 error1 = -error1; 2352 2353 error2 = org_center - ( cur_pos1 + d_off ); 2354 if ( error2 < 0 ) 2355 error2 = -error2; 2356 2357 if ( error1 < error2 ) 2358 cur_pos1 -= u_off; 2359 else 2360 cur_pos1 += d_off; 2361 2362 edge->pos = cur_pos1 - cur_len / 2; 2363 edge2->pos = edge->pos + cur_len; 2364 } 2365 else 2366 edge->pos = FT_PIX_ROUND( edge->opos ); 2367 2368 anchor = edge; 2369 edge->flags |= AF_EDGE_DONE; 2370 2371 FT_TRACE5(( " ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f)" 2372 " snapped to %.2f and %.2f\n", 2373 edge - edges, edge->opos / 64.0, 2374 edge2 - edges, edge2->opos / 64.0, 2375 edge->pos / 64.0, edge2->pos / 64.0 )); 2376 2377 af_latin_align_linked_edge( hints, dim, edge, edge2 ); 2378 2379 #ifdef FT_DEBUG_LEVEL_TRACE 2380 num_actions += 2; 2381 #endif 2382 } 2383 else 2384 { 2385 FT_Pos org_pos, org_len, org_center, cur_len; 2386 FT_Pos cur_pos1, cur_pos2, delta1, delta2; 2387 2388 2389 org_pos = anchor->pos + ( edge->opos - anchor->opos ); 2390 org_len = edge2->opos - edge->opos; 2391 org_center = org_pos + ( org_len >> 1 ); 2392 2393 cur_len = af_latin_compute_stem_width( 2394 hints, dim, org_len, 2395 (AF_Edge_Flags)edge->flags, 2396 (AF_Edge_Flags)edge2->flags ); 2397 2398 if ( edge2->flags & AF_EDGE_DONE ) 2399 { 2400 FT_TRACE5(( " ADJUST: edge %d (pos=%.2f) moved to %.2f\n", 2401 edge - edges, edge->pos / 64.0, 2402 ( edge2->pos - cur_len ) / 64.0 )); 2403 2404 edge->pos = edge2->pos - cur_len; 2405 } 2406 2407 else if ( cur_len < 96 ) 2408 { 2409 FT_Pos u_off, d_off; 2410 2411 2412 cur_pos1 = FT_PIX_ROUND( org_center ); 2413 2414 if ( cur_len <= 64 ) 2415 { 2416 u_off = 32; 2417 d_off = 32; 2418 } 2419 else 2420 { 2421 u_off = 38; 2422 d_off = 26; 2423 } 2424 2425 delta1 = org_center - ( cur_pos1 - u_off ); 2426 if ( delta1 < 0 ) 2427 delta1 = -delta1; 2428 2429 delta2 = org_center - ( cur_pos1 + d_off ); 2430 if ( delta2 < 0 ) 2431 delta2 = -delta2; 2432 2433 if ( delta1 < delta2 ) 2434 cur_pos1 -= u_off; 2435 else 2436 cur_pos1 += d_off; 2437 2438 edge->pos = cur_pos1 - cur_len / 2; 2439 edge2->pos = cur_pos1 + cur_len / 2; 2440 2441 FT_TRACE5(( " STEM: edge %d (opos=%.2f) linked to %d (opos=%.2f)" 2442 " snapped to %.2f and %.2f\n", 2443 edge - edges, edge->opos / 64.0, 2444 edge2 - edges, edge2->opos / 64.0, 2445 edge->pos / 64.0, edge2->pos / 64.0 )); 2446 } 2447 2448 else 2449 { 2450 org_pos = anchor->pos + ( edge->opos - anchor->opos ); 2451 org_len = edge2->opos - edge->opos; 2452 org_center = org_pos + ( org_len >> 1 ); 2453 2454 cur_len = af_latin_compute_stem_width( 2455 hints, dim, org_len, 2456 (AF_Edge_Flags)edge->flags, 2457 (AF_Edge_Flags)edge2->flags ); 2458 2459 cur_pos1 = FT_PIX_ROUND( org_pos ); 2460 delta1 = cur_pos1 + ( cur_len >> 1 ) - org_center; 2461 if ( delta1 < 0 ) 2462 delta1 = -delta1; 2463 2464 cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len; 2465 delta2 = cur_pos2 + ( cur_len >> 1 ) - org_center; 2466 if ( delta2 < 0 ) 2467 delta2 = -delta2; 2468 2469 edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2; 2470 edge2->pos = edge->pos + cur_len; 2471 2472 FT_TRACE5(( " STEM: edge %d (opos=%.2f) linked to %d (opos=%.2f)" 2473 " snapped to %.2f and %.2f\n", 2474 edge - edges, edge->opos / 64.0, 2475 edge2 - edges, edge2->opos / 64.0, 2476 edge->pos / 64.0, edge2->pos / 64.0 )); 2477 } 2478 2479 #ifdef FT_DEBUG_LEVEL_TRACE 2480 num_actions++; 2481 #endif 2482 2483 edge->flags |= AF_EDGE_DONE; 2484 edge2->flags |= AF_EDGE_DONE; 2485 2486 if ( edge > edges && edge->pos < edge[-1].pos ) 2487 { 2488 #ifdef FT_DEBUG_LEVEL_TRACE 2489 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n", 2490 edge - edges, edge->pos / 64.0, edge[-1].pos / 64.0 )); 2491 2492 num_actions++; 2493 #endif 2494 2495 edge->pos = edge[-1].pos; 2496 } 2497 } 2498 } 2499 2500 /* make sure that lowercase m's maintain their symmetry */ 2501 2502 /* In general, lowercase m's have six vertical edges if they are sans */ 2503 /* serif, or twelve if they are with serifs. This implementation is */ 2504 /* based on that assumption, and seems to work very well with most */ 2505 /* faces. However, if for a certain face this assumption is not */ 2506 /* true, the m is just rendered like before. In addition, any stem */ 2507 /* correction will only be applied to symmetrical glyphs (even if the */ 2508 /* glyph is not an m), so the potential for unwanted distortion is */ 2509 /* relatively low. */ 2510 2511 /* We don't handle horizontal edges since we can't easily assure that */ 2512 /* the third (lowest) stem aligns with the base line; it might end up */ 2513 /* one pixel higher or lower. */ 2514 2515 n_edges = edge_limit - edges; 2516 if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) ) 2517 { 2518 AF_Edge edge1, edge2, edge3; 2519 FT_Pos dist1, dist2, span, delta; 2520 2521 2522 if ( n_edges == 6 ) 2523 { 2524 edge1 = edges; 2525 edge2 = edges + 2; 2526 edge3 = edges + 4; 2527 } 2528 else 2529 { 2530 edge1 = edges + 1; 2531 edge2 = edges + 5; 2532 edge3 = edges + 9; 2533 } 2534 2535 dist1 = edge2->opos - edge1->opos; 2536 dist2 = edge3->opos - edge2->opos; 2537 2538 span = dist1 - dist2; 2539 if ( span < 0 ) 2540 span = -span; 2541 2542 if ( span < 8 ) 2543 { 2544 delta = edge3->pos - ( 2 * edge2->pos - edge1->pos ); 2545 edge3->pos -= delta; 2546 if ( edge3->link ) 2547 edge3->link->pos -= delta; 2548 2549 /* move the serifs along with the stem */ 2550 if ( n_edges == 12 ) 2551 { 2552 ( edges + 8 )->pos -= delta; 2553 ( edges + 11 )->pos -= delta; 2554 } 2555 2556 edge3->flags |= AF_EDGE_DONE; 2557 if ( edge3->link ) 2558 edge3->link->flags |= AF_EDGE_DONE; 2559 } 2560 } 2561 2562 if ( has_serifs || !anchor ) 2563 { 2564 /* 2565 * now hint the remaining edges (serifs and single) in order 2566 * to complete our processing 2567 */ 2568 for ( edge = edges; edge < edge_limit; edge++ ) 2569 { 2570 FT_Pos delta; 2571 2572 2573 if ( edge->flags & AF_EDGE_DONE ) 2574 continue; 2575 2576 delta = 1000; 2577 2578 if ( edge->serif ) 2579 { 2580 delta = edge->serif->opos - edge->opos; 2581 if ( delta < 0 ) 2582 delta = -delta; 2583 } 2584 2585 if ( delta < 64 + 16 ) 2586 { 2587 af_latin_align_serif_edge( hints, edge->serif, edge ); 2588 FT_TRACE5(( " SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f)" 2589 " aligned to %.2f\n", 2590 edge - edges, edge->opos / 64.0, 2591 edge->serif - edges, edge->serif->opos / 64.0, 2592 edge->pos / 64.0 )); 2593 } 2594 else if ( !anchor ) 2595 { 2596 edge->pos = FT_PIX_ROUND( edge->opos ); 2597 anchor = edge; 2598 FT_TRACE5(( " SERIF_ANCHOR: edge %d (opos=%.2f)" 2599 " snapped to %.2f\n", 2600 edge-edges, edge->opos / 64.0, edge->pos / 64.0 )); 2601 } 2602 else 2603 { 2604 AF_Edge before, after; 2605 2606 2607 for ( before = edge - 1; before >= edges; before-- ) 2608 if ( before->flags & AF_EDGE_DONE ) 2609 break; 2610 2611 for ( after = edge + 1; after < edge_limit; after++ ) 2612 if ( after->flags & AF_EDGE_DONE ) 2613 break; 2614 2615 if ( before >= edges && before < edge && 2616 after < edge_limit && after > edge ) 2617 { 2618 if ( after->opos == before->opos ) 2619 edge->pos = before->pos; 2620 else 2621 edge->pos = before->pos + 2622 FT_MulDiv( edge->opos - before->opos, 2623 after->pos - before->pos, 2624 after->opos - before->opos ); 2625 2626 FT_TRACE5(( " SERIF_LINK1: edge %d (opos=%.2f) snapped to %.2f" 2627 " from %d (opos=%.2f)\n", 2628 edge - edges, edge->opos / 64.0, 2629 edge->pos / 64.0, 2630 before - edges, before->opos / 64.0 )); 2631 } 2632 else 2633 { 2634 edge->pos = anchor->pos + 2635 ( ( edge->opos - anchor->opos + 16 ) & ~31 ); 2636 FT_TRACE5(( " SERIF_LINK2: edge %d (opos=%.2f)" 2637 " snapped to %.2f\n", 2638 edge - edges, edge->opos / 64.0, edge->pos / 64.0 )); 2639 } 2640 } 2641 2642 #ifdef FT_DEBUG_LEVEL_TRACE 2643 num_actions++; 2644 #endif 2645 edge->flags |= AF_EDGE_DONE; 2646 2647 if ( edge > edges && edge->pos < edge[-1].pos ) 2648 { 2649 #ifdef FT_DEBUG_LEVEL_TRACE 2650 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n", 2651 edge - edges, edge->pos / 64.0, edge[-1].pos / 64.0 )); 2652 2653 num_actions++; 2654 #endif 2655 edge->pos = edge[-1].pos; 2656 } 2657 2658 if ( edge + 1 < edge_limit && 2659 edge[1].flags & AF_EDGE_DONE && 2660 edge->pos > edge[1].pos ) 2661 { 2662 #ifdef FT_DEBUG_LEVEL_TRACE 2663 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n", 2664 edge - edges, edge->pos / 64.0, edge[1].pos / 64.0 )); 2665 2666 num_actions++; 2667 #endif 2668 2669 edge->pos = edge[1].pos; 2670 } 2671 } 2672 } 2673 2674 #ifdef FT_DEBUG_LEVEL_TRACE 2675 if ( !num_actions ) 2676 FT_TRACE5(( " (none)\n" )); 2677 FT_TRACE5(( "\n" )); 2678 #endif 2679 } 2680 2681 2682 /* Apply the complete hinting algorithm to a latin glyph. */ 2683 2684 static FT_Error af_latin_hints_apply(AF_GlyphHints hints,FT_Outline * outline,AF_LatinMetrics metrics)2685 af_latin_hints_apply( AF_GlyphHints hints, 2686 FT_Outline* outline, 2687 AF_LatinMetrics metrics ) 2688 { 2689 FT_Error error; 2690 int dim; 2691 2692 2693 error = af_glyph_hints_reload( hints, outline ); 2694 if ( error ) 2695 goto Exit; 2696 2697 /* analyze glyph outline */ 2698 #ifdef AF_CONFIG_OPTION_USE_WARPER 2699 if ( metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT || 2700 AF_HINTS_DO_HORIZONTAL( hints ) ) 2701 #else 2702 if ( AF_HINTS_DO_HORIZONTAL( hints ) ) 2703 #endif 2704 { 2705 error = af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ ); 2706 if ( error ) 2707 goto Exit; 2708 } 2709 2710 if ( AF_HINTS_DO_VERTICAL( hints ) ) 2711 { 2712 error = af_latin_hints_detect_features( hints, AF_DIMENSION_VERT ); 2713 if ( error ) 2714 goto Exit; 2715 2716 af_latin_hints_compute_blue_edges( hints, metrics ); 2717 } 2718 2719 /* grid-fit the outline */ 2720 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 2721 { 2722 #ifdef AF_CONFIG_OPTION_USE_WARPER 2723 if ( dim == AF_DIMENSION_HORZ && 2724 metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT ) 2725 { 2726 AF_WarperRec warper; 2727 FT_Fixed scale; 2728 FT_Pos delta; 2729 2730 2731 af_warper_compute( &warper, hints, (AF_Dimension)dim, 2732 &scale, &delta ); 2733 af_glyph_hints_scale_dim( hints, (AF_Dimension)dim, 2734 scale, delta ); 2735 continue; 2736 } 2737 #endif 2738 2739 if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) || 2740 ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) ) ) 2741 { 2742 af_latin_hint_edges( hints, (AF_Dimension)dim ); 2743 af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim ); 2744 af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim ); 2745 af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim ); 2746 } 2747 } 2748 2749 af_glyph_hints_save( hints, outline ); 2750 2751 Exit: 2752 return error; 2753 } 2754 2755 2756 /*************************************************************************/ 2757 /*************************************************************************/ 2758 /***** *****/ 2759 /***** L A T I N S C R I P T C L A S S *****/ 2760 /***** *****/ 2761 /*************************************************************************/ 2762 /*************************************************************************/ 2763 2764 2765 AF_DEFINE_WRITING_SYSTEM_CLASS( 2766 af_latin_writing_system_class, 2767 2768 AF_WRITING_SYSTEM_LATIN, 2769 2770 sizeof ( AF_LatinMetricsRec ), 2771 2772 (AF_WritingSystem_InitMetricsFunc) af_latin_metrics_init, 2773 (AF_WritingSystem_ScaleMetricsFunc)af_latin_metrics_scale, 2774 (AF_WritingSystem_DoneMetricsFunc) NULL, 2775 2776 (AF_WritingSystem_InitHintsFunc) af_latin_hints_init, 2777 (AF_WritingSystem_ApplyHintsFunc) af_latin_hints_apply 2778 ) 2779 2780 2781 /* END */ 2782