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 ) 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 /* 175 * We assume that the glyphs selected for the stem width 176 * computation are `featureless' enough so that the linking 177 * algorithm works fine without adjustments of its scoring 178 * function. 179 */ 180 af_latin_hints_link_segments( hints, 181 0, 182 NULL, 183 (AF_Dimension)dim ); 184 185 seg = axhints->segments; 186 limit = seg + axhints->num_segments; 187 188 for ( ; seg < limit; seg++ ) 189 { 190 link = seg->link; 191 192 /* we only consider stem segments there! */ 193 if ( link && link->link == seg && link > seg ) 194 { 195 FT_Pos dist; 196 197 198 dist = seg->pos - link->pos; 199 if ( dist < 0 ) 200 dist = -dist; 201 202 if ( num_widths < AF_LATIN_MAX_WIDTHS ) 203 axis->widths[num_widths++].org = dist; 204 } 205 } 206 207 /* this also replaces multiple almost identical stem widths */ 208 /* with a single one (the value 100 is heuristic) */ 209 af_sort_and_quantize_widths( &num_widths, axis->widths, 210 dummy->units_per_em / 100 ); 211 axis->width_count = num_widths; 212 } 213 214 Exit: 215 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 216 { 217 AF_LatinAxis axis = &metrics->axis[dim]; 218 FT_Pos stdw; 219 220 221 stdw = ( axis->width_count > 0 ) ? axis->widths[0].org 222 : AF_LATIN_CONSTANT( metrics, 50 ); 223 224 /* let's try 20% of the smallest width */ 225 axis->edge_distance_threshold = stdw / 5; 226 axis->standard_width = stdw; 227 axis->extra_light = 0; 228 229 #ifdef FT_DEBUG_LEVEL_TRACE 230 { 231 FT_UInt i; 232 233 234 FT_TRACE5(( "%s widths:\n", 235 dim == AF_DIMENSION_VERT ? "horizontal" 236 : "vertical" )); 237 238 FT_TRACE5(( " %d (standard)", axis->standard_width )); 239 for ( i = 1; i < axis->width_count; i++ ) 240 FT_TRACE5(( " %d", axis->widths[i].org )); 241 242 FT_TRACE5(( "\n" )); 243 } 244 #endif 245 } 246 } 247 248 FT_TRACE5(( "\n" )); 249 250 af_glyph_hints_done( hints ); 251 } 252 253 254 /* Find all blue zones. Flat segments give the reference points, */ 255 /* round segments the overshoot positions. */ 256 257 static void 258 af_latin_metrics_init_blues( AF_LatinMetrics metrics, 259 FT_Face face ) 260 { 261 FT_Pos flats [AF_BLUE_STRING_MAX_LEN]; 262 FT_Pos rounds[AF_BLUE_STRING_MAX_LEN]; 263 264 FT_Int num_flats; 265 FT_Int num_rounds; 266 267 AF_LatinBlue blue; 268 FT_Error error; 269 AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT]; 270 FT_Outline outline; 271 272 AF_StyleClass sc = metrics->root.style_class; 273 274 AF_Blue_Stringset bss = sc->blue_stringset; 275 const AF_Blue_StringRec* bs = &af_blue_stringsets[bss]; 276 277 278 /* we walk over the blue character strings as specified in the */ 279 /* style's entry in the `af_blue_stringset' array */ 280 281 FT_TRACE5(( "latin blue zones computation\n" 282 "============================\n" 283 "\n" )); 284 285 for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ ) 286 { 287 const char* p = &af_blue_strings[bs->string]; 288 FT_Pos* blue_ref; 289 FT_Pos* blue_shoot; 290 291 292 #ifdef FT_DEBUG_LEVEL_TRACE 293 { 294 FT_Bool have_flag = 0; 295 296 297 FT_TRACE5(( "blue zone %d", axis->blue_count )); 298 299 if ( bs->properties ) 300 { 301 FT_TRACE5(( " (" )); 302 303 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 304 { 305 FT_TRACE5(( "top" )); 306 have_flag = 1; 307 } 308 309 if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) 310 { 311 if ( have_flag ) 312 FT_TRACE5(( ", " )); 313 FT_TRACE5(( "neutral" )); 314 have_flag = 1; 315 } 316 317 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) 318 { 319 if ( have_flag ) 320 FT_TRACE5(( ", " )); 321 FT_TRACE5(( "small top" )); 322 have_flag = 1; 323 } 324 325 if ( AF_LATIN_IS_LONG_BLUE( bs ) ) 326 { 327 if ( have_flag ) 328 FT_TRACE5(( ", " )); 329 FT_TRACE5(( "long" )); 330 } 331 332 FT_TRACE5(( ")" )); 333 } 334 335 FT_TRACE5(( ":\n" )); 336 } 337 #endif /* FT_DEBUG_LEVEL_TRACE */ 338 339 num_flats = 0; 340 num_rounds = 0; 341 342 while ( *p ) 343 { 344 FT_ULong ch; 345 FT_ULong glyph_index; 346 FT_Long y_offset; 347 FT_Pos best_y; /* same as points.y */ 348 FT_Int best_point, best_contour_first, best_contour_last; 349 FT_Vector* points; 350 FT_Bool round = 0; 351 352 353 GET_UTF8_CHAR( ch, p ); 354 355 /* load the character in the face -- skip unknown or empty ones */ 356 af_get_char_index( &metrics->root, ch, &glyph_index, &y_offset ); 357 if ( glyph_index == 0 ) 358 { 359 FT_TRACE5(( " U+%04lX unavailable\n", ch )); 360 continue; 361 } 362 363 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); 364 outline = face->glyph->outline; 365 if ( error || outline.n_points <= 0 ) 366 { 367 FT_TRACE5(( " U+%04lX contains no outlines\n", ch )); 368 continue; 369 } 370 371 /* now compute min or max point indices and coordinates */ 372 points = outline.points; 373 best_point = -1; 374 best_y = 0; /* make compiler happy */ 375 best_contour_first = 0; /* ditto */ 376 best_contour_last = 0; /* ditto */ 377 378 { 379 FT_Int nn; 380 FT_Int first = 0; 381 FT_Int last = -1; 382 383 384 for ( nn = 0; nn < outline.n_contours; first = last + 1, nn++ ) 385 { 386 FT_Int old_best_point = best_point; 387 FT_Int pp; 388 389 390 last = outline.contours[nn]; 391 392 /* Avoid single-point contours since they are never rasterized. */ 393 /* In some fonts, they correspond to mark attachment points */ 394 /* that are way outside of the glyph's real outline. */ 395 if ( last <= first ) 396 continue; 397 398 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 399 { 400 for ( pp = first; pp <= last; pp++ ) 401 if ( best_point < 0 || points[pp].y > best_y ) 402 { 403 best_point = pp; 404 best_y = points[pp].y; 405 } 406 } 407 else 408 { 409 for ( pp = first; pp <= last; pp++ ) 410 if ( best_point < 0 || points[pp].y < best_y ) 411 { 412 best_point = pp; 413 best_y = points[pp].y; 414 } 415 } 416 417 if ( best_point != old_best_point ) 418 { 419 best_contour_first = first; 420 best_contour_last = last; 421 } 422 } 423 } 424 425 /* now check whether the point belongs to a straight or round */ 426 /* segment; we first need to find in which contour the extremum */ 427 /* lies, then inspect its previous and next points */ 428 if ( best_point >= 0 ) 429 { 430 FT_Pos best_x = points[best_point].x; 431 FT_Int prev, next; 432 FT_Int best_segment_first, best_segment_last; 433 FT_Int best_on_point_first, best_on_point_last; 434 FT_Pos dist; 435 436 437 best_segment_first = best_point; 438 best_segment_last = best_point; 439 440 if ( FT_CURVE_TAG( outline.tags[best_point] ) == FT_CURVE_TAG_ON ) 441 { 442 best_on_point_first = best_point; 443 best_on_point_last = best_point; 444 } 445 else 446 { 447 best_on_point_first = -1; 448 best_on_point_last = -1; 449 } 450 451 /* look for the previous and next points on the contour */ 452 /* that are not on the same Y coordinate, then threshold */ 453 /* the `closeness'... */ 454 prev = best_point; 455 next = prev; 456 457 do 458 { 459 if ( prev > best_contour_first ) 460 prev--; 461 else 462 prev = best_contour_last; 463 464 dist = FT_ABS( points[prev].y - best_y ); 465 /* accept a small distance or a small angle (both values are */ 466 /* heuristic; value 20 corresponds to approx. 2.9 degrees) */ 467 if ( dist > 5 ) 468 if ( FT_ABS( points[prev].x - best_x ) <= 20 * dist ) 469 break; 470 471 best_segment_first = prev; 472 473 if ( FT_CURVE_TAG( outline.tags[prev] ) == FT_CURVE_TAG_ON ) 474 { 475 best_on_point_first = prev; 476 if ( best_on_point_last < 0 ) 477 best_on_point_last = prev; 478 } 479 480 } while ( prev != best_point ); 481 482 do 483 { 484 if ( next < best_contour_last ) 485 next++; 486 else 487 next = best_contour_first; 488 489 dist = FT_ABS( points[next].y - best_y ); 490 if ( dist > 5 ) 491 if ( FT_ABS( points[next].x - best_x ) <= 20 * dist ) 492 break; 493 494 best_segment_last = next; 495 496 if ( FT_CURVE_TAG( outline.tags[next] ) == FT_CURVE_TAG_ON ) 497 { 498 best_on_point_last = next; 499 if ( best_on_point_first < 0 ) 500 best_on_point_first = next; 501 } 502 503 } while ( next != best_point ); 504 505 if ( AF_LATIN_IS_LONG_BLUE( bs ) ) 506 { 507 /* If this flag is set, we have an additional constraint to */ 508 /* get the blue zone distance: Find a segment of the topmost */ 509 /* (or bottommost) contour that is longer than a heuristic */ 510 /* threshold. This ensures that small bumps in the outline */ 511 /* are ignored (for example, the `vertical serifs' found in */ 512 /* many Hebrew glyph designs). */ 513 514 /* If this segment is long enough, we are done. Otherwise, */ 515 /* search the segment next to the extremum that is long */ 516 /* enough, has the same direction, and a not too large */ 517 /* vertical distance from the extremum. Note that the */ 518 /* algorithm doesn't check whether the found segment is */ 519 /* actually the one (vertically) nearest to the extremum. */ 520 521 /* heuristic threshold value */ 522 FT_Pos length_threshold = metrics->units_per_em / 25; 523 524 525 dist = FT_ABS( points[best_segment_last].x - 526 points[best_segment_first].x ); 527 528 if ( dist < length_threshold && 529 best_segment_last - best_segment_first + 2 <= 530 best_contour_last - best_contour_first ) 531 { 532 /* heuristic threshold value */ 533 FT_Pos height_threshold = metrics->units_per_em / 4; 534 535 FT_Int first; 536 FT_Int last; 537 FT_Bool hit; 538 539 /* we intentionally declare these two variables */ 540 /* outside of the loop since various compilers emit */ 541 /* incorrect warning messages otherwise, talking about */ 542 /* `possibly uninitialized variables' */ 543 FT_Int p_first = 0; /* make compiler happy */ 544 FT_Int p_last = 0; 545 546 FT_Bool left2right; 547 548 549 /* compute direction */ 550 prev = best_point; 551 552 do 553 { 554 if ( prev > best_contour_first ) 555 prev--; 556 else 557 prev = best_contour_last; 558 559 if ( points[prev].x != best_x ) 560 break; 561 562 } while ( prev != best_point ); 563 564 /* skip glyph for the degenerate case */ 565 if ( prev == best_point ) 566 continue; 567 568 left2right = FT_BOOL( points[prev].x < points[best_point].x ); 569 570 first = best_segment_last; 571 last = first; 572 hit = 0; 573 574 do 575 { 576 FT_Bool l2r; 577 FT_Pos d; 578 579 580 if ( !hit ) 581 { 582 /* no hit; adjust first point */ 583 first = last; 584 585 /* also adjust first and last on point */ 586 if ( FT_CURVE_TAG( outline.tags[first] ) == 587 FT_CURVE_TAG_ON ) 588 { 589 p_first = first; 590 p_last = first; 591 } 592 else 593 { 594 p_first = -1; 595 p_last = -1; 596 } 597 598 hit = 1; 599 } 600 601 if ( last < best_contour_last ) 602 last++; 603 else 604 last = best_contour_first; 605 606 if ( FT_ABS( best_y - points[first].y ) > height_threshold ) 607 { 608 /* vertical distance too large */ 609 hit = 0; 610 continue; 611 } 612 613 /* same test as above */ 614 dist = FT_ABS( points[last].y - points[first].y ); 615 if ( dist > 5 ) 616 if ( FT_ABS( points[last].x - points[first].x ) <= 617 20 * dist ) 618 { 619 hit = 0; 620 continue; 621 } 622 623 if ( FT_CURVE_TAG( outline.tags[last] ) == FT_CURVE_TAG_ON ) 624 { 625 p_last = last; 626 if ( p_first < 0 ) 627 p_first = last; 628 } 629 630 l2r = FT_BOOL( points[first].x < points[last].x ); 631 d = FT_ABS( points[last].x - points[first].x ); 632 633 if ( l2r == left2right && 634 d >= length_threshold ) 635 { 636 /* all constraints are met; update segment after finding */ 637 /* its end */ 638 do 639 { 640 if ( last < best_contour_last ) 641 last++; 642 else 643 last = best_contour_first; 644 645 d = FT_ABS( points[last].y - points[first].y ); 646 if ( d > 5 ) 647 if ( FT_ABS( points[next].x - points[first].x ) <= 648 20 * dist ) 649 { 650 if ( last > best_contour_first ) 651 last--; 652 else 653 last = best_contour_last; 654 break; 655 } 656 657 p_last = last; 658 659 if ( FT_CURVE_TAG( outline.tags[last] ) == 660 FT_CURVE_TAG_ON ) 661 { 662 p_last = last; 663 if ( p_first < 0 ) 664 p_first = last; 665 } 666 667 } while ( last != best_segment_first ); 668 669 best_y = points[first].y; 670 671 best_segment_first = first; 672 best_segment_last = last; 673 674 best_on_point_first = p_first; 675 best_on_point_last = p_last; 676 677 break; 678 } 679 680 } while ( last != best_segment_first ); 681 } 682 } 683 684 /* for computing blue zones, we add the y offset as returned */ 685 /* by the currently used OpenType feature -- for example, */ 686 /* superscript glyphs might be identical to subscript glyphs */ 687 /* with a vertical shift */ 688 best_y += y_offset; 689 690 FT_TRACE5(( " U+%04lX: best_y = %5ld", ch, best_y )); 691 692 /* now set the `round' flag depending on the segment's kind: */ 693 /* */ 694 /* - if the horizontal distance between the first and last */ 695 /* `on' point is larger than upem/8 (value 8 is heuristic) */ 696 /* we have a flat segment */ 697 /* - if either the first or the last point of the segment is */ 698 /* an `off' point, the segment is round, otherwise it is */ 699 /* flat */ 700 if ( best_on_point_first >= 0 && 701 best_on_point_last >= 0 && 702 (FT_UInt)( FT_ABS( points[best_on_point_last].x - 703 points[best_on_point_first].x ) ) > 704 metrics->units_per_em / 8 ) 705 round = 0; 706 else 707 round = FT_BOOL( 708 FT_CURVE_TAG( outline.tags[best_segment_first] ) != 709 FT_CURVE_TAG_ON || 710 FT_CURVE_TAG( outline.tags[best_segment_last] ) != 711 FT_CURVE_TAG_ON ); 712 713 if ( round && AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) 714 { 715 /* only use flat segments for a neutral blue zone */ 716 FT_TRACE5(( " (round, skipped)\n" )); 717 continue; 718 } 719 720 FT_TRACE5(( " (%s)\n", round ? "round" : "flat" )); 721 } 722 723 if ( round ) 724 rounds[num_rounds++] = best_y; 725 else 726 flats[num_flats++] = best_y; 727 } 728 729 if ( num_flats == 0 && num_rounds == 0 ) 730 { 731 /* 732 * we couldn't find a single glyph to compute this blue zone, 733 * we will simply ignore it then 734 */ 735 FT_TRACE5(( " empty\n" )); 736 continue; 737 } 738 739 /* we have computed the contents of the `rounds' and `flats' tables, */ 740 /* now determine the reference and overshoot position of the blue -- */ 741 /* we simply take the median value after a simple sort */ 742 af_sort_pos( num_rounds, rounds ); 743 af_sort_pos( num_flats, flats ); 744 745 blue = &axis->blues[axis->blue_count]; 746 blue_ref = &blue->ref.org; 747 blue_shoot = &blue->shoot.org; 748 749 axis->blue_count++; 750 751 if ( num_flats == 0 ) 752 { 753 *blue_ref = 754 *blue_shoot = rounds[num_rounds / 2]; 755 } 756 else if ( num_rounds == 0 ) 757 { 758 *blue_ref = 759 *blue_shoot = flats[num_flats / 2]; 760 } 761 else 762 { 763 *blue_ref = flats [num_flats / 2]; 764 *blue_shoot = rounds[num_rounds / 2]; 765 } 766 767 /* there are sometimes problems: if the overshoot position of top */ 768 /* zones is under its reference position, or the opposite for bottom */ 769 /* zones. We must thus check everything there and correct the errors */ 770 if ( *blue_shoot != *blue_ref ) 771 { 772 FT_Pos ref = *blue_ref; 773 FT_Pos shoot = *blue_shoot; 774 FT_Bool over_ref = FT_BOOL( shoot > ref ); 775 776 777 if ( AF_LATIN_IS_TOP_BLUE( bs ) ^ over_ref ) 778 { 779 *blue_ref = 780 *blue_shoot = ( shoot + ref ) / 2; 781 782 FT_TRACE5(( " [overshoot smaller than reference," 783 " taking mean value]\n" )); 784 } 785 } 786 787 blue->flags = 0; 788 if ( AF_LATIN_IS_TOP_BLUE( bs ) ) 789 blue->flags |= AF_LATIN_BLUE_TOP; 790 if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) 791 blue->flags |= AF_LATIN_BLUE_NEUTRAL; 792 793 /* 794 * The following flag is used later to adjust the y and x scales 795 * in order to optimize the pixel grid alignment of the top of small 796 * letters. 797 */ 798 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) 799 blue->flags |= AF_LATIN_BLUE_ADJUSTMENT; 800 801 FT_TRACE5(( " -> reference = %ld\n" 802 " overshoot = %ld\n", 803 *blue_ref, *blue_shoot )); 804 } 805 806 FT_TRACE5(( "\n" )); 807 808 return; 809 } 810 811 812 /* Check whether all ASCII digits have the same advance width. */ 813 814 FT_LOCAL_DEF( void ) 815 af_latin_metrics_check_digits( AF_LatinMetrics metrics, 816 FT_Face face ) 817 { 818 FT_UInt i; 819 FT_Bool started = 0, same_width = 1; 820 FT_Fixed advance, old_advance = 0; 821 822 823 /* digit `0' is 0x30 in all supported charmaps */ 824 for ( i = 0x30; i <= 0x39; i++ ) 825 { 826 FT_ULong glyph_index; 827 FT_Long y_offset; 828 829 830 af_get_char_index( &metrics->root, i, &glyph_index, &y_offset ); 831 if ( glyph_index == 0 ) 832 continue; 833 834 if ( FT_Get_Advance( face, glyph_index, 835 FT_LOAD_NO_SCALE | 836 FT_LOAD_NO_HINTING | 837 FT_LOAD_IGNORE_TRANSFORM, 838 &advance ) ) 839 continue; 840 841 if ( started ) 842 { 843 if ( advance != old_advance ) 844 { 845 same_width = 0; 846 break; 847 } 848 } 849 else 850 { 851 old_advance = advance; 852 started = 1; 853 } 854 } 855 856 metrics->root.digits_have_same_width = same_width; 857 } 858 859 860 /* Initialize global metrics. */ 861 862 FT_LOCAL_DEF( FT_Error ) 863 af_latin_metrics_init( AF_LatinMetrics metrics, 864 FT_Face face ) 865 { 866 FT_CharMap oldmap = face->charmap; 867 868 869 metrics->units_per_em = face->units_per_EM; 870 871 if ( !FT_Select_Charmap( face, FT_ENCODING_UNICODE ) ) 872 { 873 af_latin_metrics_init_widths( metrics, face ); 874 af_latin_metrics_init_blues( metrics, face ); 875 af_latin_metrics_check_digits( metrics, face ); 876 } 877 878 FT_Set_Charmap( face, oldmap ); 879 return FT_Err_Ok; 880 } 881 882 883 /* Adjust scaling value, then scale and shift widths */ 884 /* and blue zones (if applicable) for given dimension. */ 885 886 static void 887 af_latin_metrics_scale_dim( AF_LatinMetrics metrics, 888 AF_Scaler scaler, 889 AF_Dimension dim ) 890 { 891 FT_Fixed scale; 892 FT_Pos delta; 893 AF_LatinAxis axis; 894 FT_UInt nn; 895 896 897 if ( dim == AF_DIMENSION_HORZ ) 898 { 899 scale = scaler->x_scale; 900 delta = scaler->x_delta; 901 } 902 else 903 { 904 scale = scaler->y_scale; 905 delta = scaler->y_delta; 906 } 907 908 axis = &metrics->axis[dim]; 909 910 if ( axis->org_scale == scale && axis->org_delta == delta ) 911 return; 912 913 axis->org_scale = scale; 914 axis->org_delta = delta; 915 916 /* 917 * correct X and Y scale to optimize the alignment of the top of small 918 * letters to the pixel grid 919 */ 920 { 921 AF_LatinAxis Axis = &metrics->axis[AF_DIMENSION_VERT]; 922 AF_LatinBlue blue = NULL; 923 924 925 for ( nn = 0; nn < Axis->blue_count; nn++ ) 926 { 927 if ( Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT ) 928 { 929 blue = &Axis->blues[nn]; 930 break; 931 } 932 } 933 934 if ( blue ) 935 { 936 FT_Pos scaled; 937 FT_Pos threshold; 938 FT_Pos fitted; 939 FT_UInt limit; 940 FT_UInt ppem; 941 942 943 scaled = FT_MulFix( blue->shoot.org, scaler->y_scale ); 944 ppem = metrics->root.scaler.face->size->metrics.x_ppem; 945 limit = metrics->root.globals->increase_x_height; 946 threshold = 40; 947 948 /* if the `increase-x-height' property is active, */ 949 /* we round up much more often */ 950 if ( limit && 951 ppem <= limit && 952 ppem >= AF_PROP_INCREASE_X_HEIGHT_MIN ) 953 threshold = 52; 954 955 fitted = ( scaled + threshold ) & ~63; 956 957 if ( scaled != fitted ) 958 { 959 #if 0 960 if ( dim == AF_DIMENSION_HORZ ) 961 { 962 if ( fitted < scaled ) 963 scale -= scale / 50; /* scale *= 0.98 */ 964 } 965 else 966 #endif 967 if ( dim == AF_DIMENSION_VERT ) 968 { 969 scale = FT_MulDiv( scale, fitted, scaled ); 970 971 FT_TRACE5(( 972 "af_latin_metrics_scale_dim:" 973 " x height alignment (style `%s'):\n" 974 " " 975 " vertical scaling changed from %.4f to %.4f (by %d%%)\n" 976 "\n", 977 af_style_names[metrics->root.style_class->style], 978 axis->org_scale / 65536.0, 979 scale / 65536.0, 980 ( fitted - scaled ) * 100 / scaled )); 981 } 982 } 983 } 984 } 985 986 axis->scale = scale; 987 axis->delta = delta; 988 989 if ( dim == AF_DIMENSION_HORZ ) 990 { 991 metrics->root.scaler.x_scale = scale; 992 metrics->root.scaler.x_delta = delta; 993 } 994 else 995 { 996 metrics->root.scaler.y_scale = scale; 997 metrics->root.scaler.y_delta = delta; 998 } 999 1000 FT_TRACE5(( "%s widths (style `%s')\n", 1001 dim == AF_DIMENSION_HORZ ? "horizontal" : "vertical", 1002 af_style_names[metrics->root.style_class->style] )); 1003 1004 /* scale the widths */ 1005 for ( nn = 0; nn < axis->width_count; nn++ ) 1006 { 1007 AF_Width width = axis->widths + nn; 1008 1009 1010 width->cur = FT_MulFix( width->org, scale ); 1011 width->fit = width->cur; 1012 1013 FT_TRACE5(( " %d scaled to %.2f\n", 1014 width->org, 1015 width->cur / 64.0 )); 1016 } 1017 1018 FT_TRACE5(( "\n" )); 1019 1020 /* an extra-light axis corresponds to a standard width that is */ 1021 /* smaller than 5/8 pixels */ 1022 axis->extra_light = 1023 (FT_Bool)( FT_MulFix( axis->standard_width, scale ) < 32 + 8 ); 1024 1025 #ifdef FT_DEBUG_LEVEL_TRACE 1026 if ( axis->extra_light ) 1027 FT_TRACE5(( "`%s' style is extra light (at current resolution)\n" 1028 "\n", 1029 af_style_names[metrics->root.style_class->style] )); 1030 #endif 1031 1032 if ( dim == AF_DIMENSION_VERT ) 1033 { 1034 FT_TRACE5(( "blue zones (style `%s')\n", 1035 af_style_names[metrics->root.style_class->style] )); 1036 1037 /* scale the blue zones */ 1038 for ( nn = 0; nn < axis->blue_count; nn++ ) 1039 { 1040 AF_LatinBlue blue = &axis->blues[nn]; 1041 FT_Pos dist; 1042 1043 1044 blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta; 1045 blue->ref.fit = blue->ref.cur; 1046 blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta; 1047 blue->shoot.fit = blue->shoot.cur; 1048 blue->flags &= ~AF_LATIN_BLUE_ACTIVE; 1049 1050 /* a blue zone is only active if it is less than 3/4 pixels tall */ 1051 dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale ); 1052 if ( dist <= 48 && dist >= -48 ) 1053 { 1054 #if 0 1055 FT_Pos delta1; 1056 #endif 1057 FT_Pos delta2; 1058 1059 1060 /* use discrete values for blue zone widths */ 1061 1062 #if 0 1063 1064 /* generic, original code */ 1065 delta1 = blue->shoot.org - blue->ref.org; 1066 delta2 = delta1; 1067 if ( delta1 < 0 ) 1068 delta2 = -delta2; 1069 1070 delta2 = FT_MulFix( delta2, scale ); 1071 1072 if ( delta2 < 32 ) 1073 delta2 = 0; 1074 else if ( delta2 < 64 ) 1075 delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 ); 1076 else 1077 delta2 = FT_PIX_ROUND( delta2 ); 1078 1079 if ( delta1 < 0 ) 1080 delta2 = -delta2; 1081 1082 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); 1083 blue->shoot.fit = blue->ref.fit + delta2; 1084 1085 #else 1086 1087 /* simplified version due to abs(dist) <= 48 */ 1088 delta2 = dist; 1089 if ( dist < 0 ) 1090 delta2 = -delta2; 1091 1092 if ( delta2 < 32 ) 1093 delta2 = 0; 1094 else if ( delta2 < 48 ) 1095 delta2 = 32; 1096 else 1097 delta2 = 64; 1098 1099 if ( dist < 0 ) 1100 delta2 = -delta2; 1101 1102 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); 1103 blue->shoot.fit = blue->ref.fit - delta2; 1104 1105 #endif 1106 1107 blue->flags |= AF_LATIN_BLUE_ACTIVE; 1108 1109 FT_TRACE5(( " reference %d: %d scaled to %.2f%s\n" 1110 " overshoot %d: %d scaled to %.2f%s\n", 1111 nn, 1112 blue->ref.org, 1113 blue->ref.fit / 64.0, 1114 blue->flags & AF_LATIN_BLUE_ACTIVE ? "" 1115 : " (inactive)", 1116 nn, 1117 blue->shoot.org, 1118 blue->shoot.fit / 64.0, 1119 blue->flags & AF_LATIN_BLUE_ACTIVE ? "" 1120 : " (inactive)" )); 1121 } 1122 } 1123 } 1124 } 1125 1126 1127 /* Scale global values in both directions. */ 1128 1129 FT_LOCAL_DEF( void ) 1130 af_latin_metrics_scale( AF_LatinMetrics metrics, 1131 AF_Scaler scaler ) 1132 { 1133 metrics->root.scaler.render_mode = scaler->render_mode; 1134 metrics->root.scaler.face = scaler->face; 1135 metrics->root.scaler.flags = scaler->flags; 1136 1137 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ ); 1138 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT ); 1139 } 1140 1141 1142 /*************************************************************************/ 1143 /*************************************************************************/ 1144 /***** *****/ 1145 /***** L A T I N G L Y P H A N A L Y S I S *****/ 1146 /***** *****/ 1147 /*************************************************************************/ 1148 /*************************************************************************/ 1149 1150 1151 /* Walk over all contours and compute its segments. */ 1152 1153 FT_LOCAL_DEF( FT_Error ) 1154 af_latin_hints_compute_segments( AF_GlyphHints hints, 1155 AF_Dimension dim ) 1156 { 1157 AF_AxisHints axis = &hints->axis[dim]; 1158 FT_Memory memory = hints->memory; 1159 FT_Error error = FT_Err_Ok; 1160 AF_Segment segment = NULL; 1161 AF_SegmentRec seg0; 1162 AF_Point* contour = hints->contours; 1163 AF_Point* contour_limit = contour + hints->num_contours; 1164 AF_Direction major_dir, segment_dir; 1165 1166 1167 FT_ZERO( &seg0 ); 1168 seg0.score = 32000; 1169 seg0.flags = AF_EDGE_NORMAL; 1170 1171 major_dir = (AF_Direction)FT_ABS( axis->major_dir ); 1172 segment_dir = major_dir; 1173 1174 axis->num_segments = 0; 1175 1176 /* set up (u,v) in each point */ 1177 if ( dim == AF_DIMENSION_HORZ ) 1178 { 1179 AF_Point point = hints->points; 1180 AF_Point limit = point + hints->num_points; 1181 1182 1183 for ( ; point < limit; point++ ) 1184 { 1185 point->u = point->fx; 1186 point->v = point->fy; 1187 } 1188 } 1189 else 1190 { 1191 AF_Point point = hints->points; 1192 AF_Point limit = point + hints->num_points; 1193 1194 1195 for ( ; point < limit; point++ ) 1196 { 1197 point->u = point->fy; 1198 point->v = point->fx; 1199 } 1200 } 1201 1202 /* do each contour separately */ 1203 for ( ; contour < contour_limit; contour++ ) 1204 { 1205 AF_Point point = contour[0]; 1206 AF_Point last = point->prev; 1207 int on_edge = 0; 1208 FT_Pos min_pos = 32000; /* minimum segment pos != min_coord */ 1209 FT_Pos max_pos = -32000; /* maximum segment pos != max_coord */ 1210 FT_Bool passed; 1211 1212 1213 if ( point == last ) /* skip singletons -- just in case */ 1214 continue; 1215 1216 if ( FT_ABS( last->out_dir ) == major_dir && 1217 FT_ABS( point->out_dir ) == major_dir ) 1218 { 1219 /* we are already on an edge, try to locate its start */ 1220 last = point; 1221 1222 for (;;) 1223 { 1224 point = point->prev; 1225 if ( FT_ABS( point->out_dir ) != major_dir ) 1226 { 1227 point = point->next; 1228 break; 1229 } 1230 if ( point == last ) 1231 break; 1232 } 1233 } 1234 1235 last = point; 1236 passed = 0; 1237 1238 for (;;) 1239 { 1240 FT_Pos u, v; 1241 1242 1243 if ( on_edge ) 1244 { 1245 u = point->u; 1246 if ( u < min_pos ) 1247 min_pos = u; 1248 if ( u > max_pos ) 1249 max_pos = u; 1250 1251 if ( point->out_dir != segment_dir || point == last ) 1252 { 1253 /* we are just leaving an edge; record a new segment! */ 1254 segment->last = point; 1255 segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); 1256 1257 /* a segment is round if either its first or last point */ 1258 /* is a control point */ 1259 if ( ( segment->first->flags | point->flags ) & 1260 AF_FLAG_CONTROL ) 1261 segment->flags |= AF_EDGE_ROUND; 1262 1263 /* compute segment size */ 1264 min_pos = max_pos = point->v; 1265 1266 v = segment->first->v; 1267 if ( v < min_pos ) 1268 min_pos = v; 1269 if ( v > max_pos ) 1270 max_pos = v; 1271 1272 segment->min_coord = (FT_Short)min_pos; 1273 segment->max_coord = (FT_Short)max_pos; 1274 segment->height = (FT_Short)( segment->max_coord - 1275 segment->min_coord ); 1276 1277 on_edge = 0; 1278 segment = NULL; 1279 /* fall through */ 1280 } 1281 } 1282 1283 /* now exit if we are at the start/end point */ 1284 if ( point == last ) 1285 { 1286 if ( passed ) 1287 break; 1288 passed = 1; 1289 } 1290 1291 if ( !on_edge && FT_ABS( point->out_dir ) == major_dir ) 1292 { 1293 /* this is the start of a new segment! */ 1294 segment_dir = (AF_Direction)point->out_dir; 1295 1296 /* clear all segment fields */ 1297 error = af_axis_hints_new_segment( axis, memory, &segment ); 1298 if ( error ) 1299 goto Exit; 1300 1301 segment[0] = seg0; 1302 segment->dir = (FT_Char)segment_dir; 1303 min_pos = max_pos = point->u; 1304 segment->first = point; 1305 segment->last = point; 1306 on_edge = 1; 1307 } 1308 1309 point = point->next; 1310 } 1311 1312 } /* contours */ 1313 1314 1315 /* now slightly increase the height of segments if this makes */ 1316 /* sense -- this is used to better detect and ignore serifs */ 1317 { 1318 AF_Segment segments = axis->segments; 1319 AF_Segment segments_end = segments + axis->num_segments; 1320 1321 1322 for ( segment = segments; segment < segments_end; segment++ ) 1323 { 1324 AF_Point first = segment->first; 1325 AF_Point last = segment->last; 1326 FT_Pos first_v = first->v; 1327 FT_Pos last_v = last->v; 1328 1329 1330 if ( first == last ) 1331 continue; 1332 1333 if ( first_v < last_v ) 1334 { 1335 AF_Point p; 1336 1337 1338 p = first->prev; 1339 if ( p->v < first_v ) 1340 segment->height = (FT_Short)( segment->height + 1341 ( ( first_v - p->v ) >> 1 ) ); 1342 1343 p = last->next; 1344 if ( p->v > last_v ) 1345 segment->height = (FT_Short)( segment->height + 1346 ( ( p->v - last_v ) >> 1 ) ); 1347 } 1348 else 1349 { 1350 AF_Point p; 1351 1352 1353 p = first->prev; 1354 if ( p->v > first_v ) 1355 segment->height = (FT_Short)( segment->height + 1356 ( ( p->v - first_v ) >> 1 ) ); 1357 1358 p = last->next; 1359 if ( p->v < last_v ) 1360 segment->height = (FT_Short)( segment->height + 1361 ( ( last_v - p->v ) >> 1 ) ); 1362 } 1363 } 1364 } 1365 1366 Exit: 1367 return error; 1368 } 1369 1370 1371 /* Link segments to form stems and serifs. If `width_count' and */ 1372 /* `widths' are non-zero, use them to fine-tune the scoring function. */ 1373 1374 FT_LOCAL_DEF( void ) 1375 af_latin_hints_link_segments( AF_GlyphHints hints, 1376 FT_UInt width_count, 1377 AF_WidthRec* widths, 1378 AF_Dimension dim ) 1379 { 1380 AF_AxisHints axis = &hints->axis[dim]; 1381 AF_Segment segments = axis->segments; 1382 AF_Segment segment_limit = segments + axis->num_segments; 1383 FT_Pos len_threshold, len_score, dist_score, max_width; 1384 AF_Segment seg1, seg2; 1385 1386 1387 if ( width_count ) 1388 max_width = widths[width_count - 1].org; 1389 else 1390 max_width = 0; 1391 1392 /* a heuristic value to set up a minimum value for overlapping */ 1393 len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 ); 1394 if ( len_threshold == 0 ) 1395 len_threshold = 1; 1396 1397 /* a heuristic value to weight lengths */ 1398 len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 ); 1399 1400 /* a heuristic value to weight distances (no call to */ 1401 /* AF_LATIN_CONSTANT needed, since we work on multiples */ 1402 /* of the stem width) */ 1403 dist_score = 3000; 1404 1405 /* now compare each segment to the others */ 1406 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 1407 { 1408 /* the fake segments are introduced to hint the metrics -- */ 1409 /* we must never link them to anything */ 1410 if ( seg1->dir != axis->major_dir || seg1->first == seg1->last ) 1411 continue; 1412 1413 /* search for stems having opposite directions, */ 1414 /* with seg1 to the `left' of seg2 */ 1415 for ( seg2 = segments; seg2 < segment_limit; seg2++ ) 1416 { 1417 FT_Pos pos1 = seg1->pos; 1418 FT_Pos pos2 = seg2->pos; 1419 1420 1421 if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 ) 1422 { 1423 /* compute distance between the two segments */ 1424 FT_Pos min = seg1->min_coord; 1425 FT_Pos max = seg1->max_coord; 1426 FT_Pos len; 1427 1428 1429 if ( min < seg2->min_coord ) 1430 min = seg2->min_coord; 1431 1432 if ( max > seg2->max_coord ) 1433 max = seg2->max_coord; 1434 1435 /* compute maximum coordinate difference of the two segments */ 1436 /* (this is, how much they overlap) */ 1437 len = max - min; 1438 if ( len >= len_threshold ) 1439 { 1440 /* 1441 * The score is the sum of two demerits indicating the 1442 * `badness' of a fit, measured along the segments' main axis 1443 * and orthogonal to it, respectively. 1444 * 1445 * o The less overlapping along the main axis, the worse it 1446 * is, causing a larger demerit. 1447 * 1448 * o The nearer the orthogonal distance to a stem width, the 1449 * better it is, causing a smaller demerit. For simplicity, 1450 * however, we only increase the demerit for values that 1451 * exceed the largest stem width. 1452 */ 1453 1454 FT_Pos dist = pos2 - pos1; 1455 1456 FT_Pos dist_demerit, score; 1457 1458 1459 if ( max_width ) 1460 { 1461 /* distance demerits are based on multiples of `max_width'; */ 1462 /* we scale by 1024 for getting more precision */ 1463 FT_Pos delta = ( dist << 10 ) / max_width - ( 1 << 10 ); 1464 1465 1466 if ( delta > 10000 ) 1467 dist_demerit = 32000; 1468 else if ( delta > 0 ) 1469 dist_demerit = delta * delta / dist_score; 1470 else 1471 dist_demerit = 0; 1472 } 1473 else 1474 dist_demerit = dist; /* default if no widths available */ 1475 1476 score = dist_demerit + len_score / len; 1477 1478 /* and we search for the smallest score */ 1479 if ( score < seg1->score ) 1480 { 1481 seg1->score = score; 1482 seg1->link = seg2; 1483 } 1484 1485 if ( score < seg2->score ) 1486 { 1487 seg2->score = score; 1488 seg2->link = seg1; 1489 } 1490 } 1491 } 1492 } 1493 } 1494 1495 /* now compute the `serif' segments, cf. explanations in `afhints.h' */ 1496 for ( seg1 = segments; seg1 < segment_limit; seg1++ ) 1497 { 1498 seg2 = seg1->link; 1499 1500 if ( seg2 ) 1501 { 1502 if ( seg2->link != seg1 ) 1503 { 1504 seg1->link = 0; 1505 seg1->serif = seg2->link; 1506 } 1507 } 1508 } 1509 } 1510 1511 1512 /* Link segments to edges, using feature analysis for selection. */ 1513 1514 FT_LOCAL_DEF( FT_Error ) 1515 af_latin_hints_compute_edges( AF_GlyphHints hints, 1516 AF_Dimension dim ) 1517 { 1518 AF_AxisHints axis = &hints->axis[dim]; 1519 FT_Error error = FT_Err_Ok; 1520 FT_Memory memory = hints->memory; 1521 AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim]; 1522 1523 AF_Segment segments = axis->segments; 1524 AF_Segment segment_limit = segments + axis->num_segments; 1525 AF_Segment seg; 1526 1527 #if 0 1528 AF_Direction up_dir; 1529 #endif 1530 FT_Fixed scale; 1531 FT_Pos edge_distance_threshold; 1532 FT_Pos segment_length_threshold; 1533 1534 1535 axis->num_edges = 0; 1536 1537 scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale 1538 : hints->y_scale; 1539 1540 #if 0 1541 up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP 1542 : AF_DIR_RIGHT; 1543 #endif 1544 1545 /* 1546 * We ignore all segments that are less than 1 pixel in length 1547 * to avoid many problems with serif fonts. We compute the 1548 * corresponding threshold in font units. 1549 */ 1550 if ( dim == AF_DIMENSION_HORZ ) 1551 segment_length_threshold = FT_DivFix( 64, hints->y_scale ); 1552 else 1553 segment_length_threshold = 0; 1554 1555 /*********************************************************************/ 1556 /* */ 1557 /* We begin by generating a sorted table of edges for the current */ 1558 /* direction. To do so, we simply scan each segment and try to find */ 1559 /* an edge in our table that corresponds to its position. */ 1560 /* */ 1561 /* If no edge is found, we create and insert a new edge in the */ 1562 /* sorted table. Otherwise, we simply add the segment to the edge's */ 1563 /* list which gets processed in the second step to compute the */ 1564 /* edge's properties. */ 1565 /* */ 1566 /* Note that the table of edges is sorted along the segment/edge */ 1567 /* position. */ 1568 /* */ 1569 /*********************************************************************/ 1570 1571 /* assure that edge distance threshold is at most 0.25px */ 1572 edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold, 1573 scale ); 1574 if ( edge_distance_threshold > 64 / 4 ) 1575 edge_distance_threshold = 64 / 4; 1576 1577 edge_distance_threshold = FT_DivFix( edge_distance_threshold, 1578 scale ); 1579 1580 for ( seg = segments; seg < segment_limit; seg++ ) 1581 { 1582 AF_Edge found = NULL; 1583 FT_Int ee; 1584 1585 1586 if ( seg->height < segment_length_threshold ) 1587 continue; 1588 1589 /* A special case for serif edges: If they are smaller than */ 1590 /* 1.5 pixels we ignore them. */ 1591 if ( seg->serif && 1592 2 * seg->height < 3 * segment_length_threshold ) 1593 continue; 1594 1595 /* look for an edge corresponding to the segment */ 1596 for ( ee = 0; ee < axis->num_edges; ee++ ) 1597 { 1598 AF_Edge edge = axis->edges + ee; 1599 FT_Pos dist; 1600 1601 1602 dist = seg->pos - edge->fpos; 1603 if ( dist < 0 ) 1604 dist = -dist; 1605 1606 if ( dist < edge_distance_threshold && edge->dir == seg->dir ) 1607 { 1608 found = edge; 1609 break; 1610 } 1611 } 1612 1613 if ( !found ) 1614 { 1615 AF_Edge edge; 1616 1617 1618 /* insert a new edge in the list and */ 1619 /* sort according to the position */ 1620 error = af_axis_hints_new_edge( axis, seg->pos, 1621 (AF_Direction)seg->dir, 1622 memory, &edge ); 1623 if ( error ) 1624 goto Exit; 1625 1626 /* add the segment to the new edge's list */ 1627 FT_ZERO( edge ); 1628 1629 edge->first = seg; 1630 edge->last = seg; 1631 edge->dir = seg->dir; 1632 edge->fpos = seg->pos; 1633 edge->opos = FT_MulFix( seg->pos, scale ); 1634 edge->pos = edge->opos; 1635 seg->edge_next = seg; 1636 } 1637 else 1638 { 1639 /* if an edge was found, simply add the segment to the edge's */ 1640 /* list */ 1641 seg->edge_next = found->first; 1642 found->last->edge_next = seg; 1643 found->last = seg; 1644 } 1645 } 1646 1647 1648 /******************************************************************/ 1649 /* */ 1650 /* Good, we now compute each edge's properties according to the */ 1651 /* segments found on its position. Basically, these are */ 1652 /* */ 1653 /* - the edge's main direction */ 1654 /* - stem edge, serif edge or both (which defaults to stem then) */ 1655 /* - rounded edge, straight or both (which defaults to straight) */ 1656 /* - link for edge */ 1657 /* */ 1658 /******************************************************************/ 1659 1660 /* first of all, set the `edge' field in each segment -- this is */ 1661 /* required in order to compute edge links */ 1662 1663 /* 1664 * Note that removing this loop and setting the `edge' field of each 1665 * segment directly in the code above slows down execution speed for 1666 * some reasons on platforms like the Sun. 1667 */ 1668 { 1669 AF_Edge edges = axis->edges; 1670 AF_Edge edge_limit = edges + axis->num_edges; 1671 AF_Edge edge; 1672 1673 1674 for ( edge = edges; edge < edge_limit; edge++ ) 1675 { 1676 seg = edge->first; 1677 if ( seg ) 1678 do 1679 { 1680 seg->edge = edge; 1681 seg = seg->edge_next; 1682 1683 } while ( seg != edge->first ); 1684 } 1685 1686 /* now compute each edge properties */ 1687 for ( edge = edges; edge < edge_limit; edge++ ) 1688 { 1689 FT_Int is_round = 0; /* does it contain round segments? */ 1690 FT_Int is_straight = 0; /* does it contain straight segments? */ 1691 #if 0 1692 FT_Pos ups = 0; /* number of upwards segments */ 1693 FT_Pos downs = 0; /* number of downwards segments */ 1694 #endif 1695 1696 1697 seg = edge->first; 1698 1699 do 1700 { 1701 FT_Bool is_serif; 1702 1703 1704 /* check for roundness of segment */ 1705 if ( seg->flags & AF_EDGE_ROUND ) 1706 is_round++; 1707 else 1708 is_straight++; 1709 1710 #if 0 1711 /* check for segment direction */ 1712 if ( seg->dir == up_dir ) 1713 ups += seg->max_coord - seg->min_coord; 1714 else 1715 downs += seg->max_coord - seg->min_coord; 1716 #endif 1717 1718 /* check for links -- if seg->serif is set, then seg->link must */ 1719 /* be ignored */ 1720 is_serif = (FT_Bool)( seg->serif && 1721 seg->serif->edge && 1722 seg->serif->edge != edge ); 1723 1724 if ( ( seg->link && seg->link->edge != NULL ) || is_serif ) 1725 { 1726 AF_Edge edge2; 1727 AF_Segment seg2; 1728 1729 1730 edge2 = edge->link; 1731 seg2 = seg->link; 1732 1733 if ( is_serif ) 1734 { 1735 seg2 = seg->serif; 1736 edge2 = edge->serif; 1737 } 1738 1739 if ( edge2 ) 1740 { 1741 FT_Pos edge_delta; 1742 FT_Pos seg_delta; 1743 1744 1745 edge_delta = edge->fpos - edge2->fpos; 1746 if ( edge_delta < 0 ) 1747 edge_delta = -edge_delta; 1748 1749 seg_delta = seg->pos - seg2->pos; 1750 if ( seg_delta < 0 ) 1751 seg_delta = -seg_delta; 1752 1753 if ( seg_delta < edge_delta ) 1754 edge2 = seg2->edge; 1755 } 1756 else 1757 edge2 = seg2->edge; 1758 1759 if ( is_serif ) 1760 { 1761 edge->serif = edge2; 1762 edge2->flags |= AF_EDGE_SERIF; 1763 } 1764 else 1765 edge->link = edge2; 1766 } 1767 1768 seg = seg->edge_next; 1769 1770 } while ( seg != edge->first ); 1771 1772 /* set the round/straight flags */ 1773 edge->flags = AF_EDGE_NORMAL; 1774 1775 if ( is_round > 0 && is_round >= is_straight ) 1776 edge->flags |= AF_EDGE_ROUND; 1777 1778 #if 0 1779 /* set the edge's main direction */ 1780 edge->dir = AF_DIR_NONE; 1781 1782 if ( ups > downs ) 1783 edge->dir = (FT_Char)up_dir; 1784 1785 else if ( ups < downs ) 1786 edge->dir = (FT_Char)-up_dir; 1787 1788 else if ( ups == downs ) 1789 edge->dir = 0; /* both up and down! */ 1790 #endif 1791 1792 /* get rid of serifs if link is set */ 1793 /* XXX: This gets rid of many unpleasant artefacts! */ 1794 /* Example: the `c' in cour.pfa at size 13 */ 1795 1796 if ( edge->serif && edge->link ) 1797 edge->serif = 0; 1798 } 1799 } 1800 1801 Exit: 1802 return error; 1803 } 1804 1805 1806 /* Detect segments and edges for given dimension. */ 1807 1808 FT_LOCAL_DEF( FT_Error ) 1809 af_latin_hints_detect_features( AF_GlyphHints hints, 1810 FT_UInt width_count, 1811 AF_WidthRec* widths, 1812 AF_Dimension dim ) 1813 { 1814 FT_Error error; 1815 1816 1817 error = af_latin_hints_compute_segments( hints, dim ); 1818 if ( !error ) 1819 { 1820 af_latin_hints_link_segments( hints, width_count, widths, dim ); 1821 1822 error = af_latin_hints_compute_edges( hints, dim ); 1823 } 1824 1825 return error; 1826 } 1827 1828 1829 /* Compute all edges which lie within blue zones. */ 1830 1831 FT_LOCAL_DEF( void ) 1832 af_latin_hints_compute_blue_edges( AF_GlyphHints hints, 1833 AF_LatinMetrics metrics ) 1834 { 1835 AF_AxisHints axis = &hints->axis[AF_DIMENSION_VERT]; 1836 AF_Edge edge = axis->edges; 1837 AF_Edge edge_limit = edge + axis->num_edges; 1838 AF_LatinAxis latin = &metrics->axis[AF_DIMENSION_VERT]; 1839 FT_Fixed scale = latin->scale; 1840 1841 1842 /* compute which blue zones are active, i.e. have their scaled */ 1843 /* size < 3/4 pixels */ 1844 1845 /* for each horizontal edge search the blue zone which is closest */ 1846 for ( ; edge < edge_limit; edge++ ) 1847 { 1848 FT_UInt bb; 1849 AF_Width best_blue = NULL; 1850 FT_Bool best_blue_is_neutral = 0; 1851 FT_Pos best_dist; /* initial threshold */ 1852 1853 1854 /* compute the initial threshold as a fraction of the EM size */ 1855 /* (the value 40 is heuristic) */ 1856 best_dist = FT_MulFix( metrics->units_per_em / 40, scale ); 1857 1858 /* assure a minimum distance of 0.5px */ 1859 if ( best_dist > 64 / 2 ) 1860 best_dist = 64 / 2; 1861 1862 for ( bb = 0; bb < latin->blue_count; bb++ ) 1863 { 1864 AF_LatinBlue blue = latin->blues + bb; 1865 FT_Bool is_top_blue, is_neutral_blue, is_major_dir; 1866 1867 1868 /* skip inactive blue zones (i.e., those that are too large) */ 1869 if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) 1870 continue; 1871 1872 /* if it is a top zone, check for right edges (against the major */ 1873 /* direction); if it is a bottom zone, check for left edges (in */ 1874 /* the major direction) -- this assumes the TrueType convention */ 1875 /* for the orientation of contours */ 1876 is_top_blue = 1877 (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_TOP ) != 0 ); 1878 is_neutral_blue = 1879 (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_NEUTRAL ) != 0); 1880 is_major_dir = 1881 FT_BOOL( edge->dir == axis->major_dir ); 1882 1883 /* neutral blue zones are handled for both directions */ 1884 if ( is_top_blue ^ is_major_dir || is_neutral_blue ) 1885 { 1886 FT_Pos dist; 1887 1888 1889 /* first of all, compare it to the reference position */ 1890 dist = edge->fpos - blue->ref.org; 1891 if ( dist < 0 ) 1892 dist = -dist; 1893 1894 dist = FT_MulFix( dist, scale ); 1895 if ( dist < best_dist ) 1896 { 1897 best_dist = dist; 1898 best_blue = &blue->ref; 1899 best_blue_is_neutral = is_neutral_blue; 1900 } 1901 1902 /* now compare it to the overshoot position and check whether */ 1903 /* the edge is rounded, and whether the edge is over the */ 1904 /* reference position of a top zone, or under the reference */ 1905 /* position of a bottom zone (provided we don't have a */ 1906 /* neutral blue zone) */ 1907 if ( edge->flags & AF_EDGE_ROUND && 1908 dist != 0 && 1909 !is_neutral_blue ) 1910 { 1911 FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org ); 1912 1913 1914 if ( is_top_blue ^ is_under_ref ) 1915 { 1916 dist = edge->fpos - blue->shoot.org; 1917 if ( dist < 0 ) 1918 dist = -dist; 1919 1920 dist = FT_MulFix( dist, scale ); 1921 if ( dist < best_dist ) 1922 { 1923 best_dist = dist; 1924 best_blue = &blue->shoot; 1925 best_blue_is_neutral = is_neutral_blue; 1926 } 1927 } 1928 } 1929 } 1930 } 1931 1932 if ( best_blue ) 1933 { 1934 edge->blue_edge = best_blue; 1935 if ( best_blue_is_neutral ) 1936 edge->flags |= AF_EDGE_NEUTRAL; 1937 } 1938 } 1939 } 1940 1941 1942 /* Initalize hinting engine. */ 1943 1944 static FT_Error 1945 af_latin_hints_init( AF_GlyphHints hints, 1946 AF_LatinMetrics metrics ) 1947 { 1948 FT_Render_Mode mode; 1949 FT_UInt32 scaler_flags, other_flags; 1950 FT_Face face = metrics->root.scaler.face; 1951 1952 1953 af_glyph_hints_rescale( hints, (AF_StyleMetrics)metrics ); 1954 1955 /* 1956 * correct x_scale and y_scale if needed, since they may have 1957 * been modified by `af_latin_metrics_scale_dim' above 1958 */ 1959 hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale; 1960 hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta; 1961 hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale; 1962 hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta; 1963 1964 /* compute flags depending on render mode, etc. */ 1965 mode = metrics->root.scaler.render_mode; 1966 1967 #if 0 /* #ifdef AF_CONFIG_OPTION_USE_WARPER */ 1968 if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V ) 1969 metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL; 1970 #endif 1971 1972 scaler_flags = hints->scaler_flags; 1973 other_flags = 0; 1974 1975 /* 1976 * We snap the width of vertical stems for the monochrome and 1977 * horizontal LCD rendering targets only. 1978 */ 1979 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD ) 1980 other_flags |= AF_LATIN_HINTS_HORZ_SNAP; 1981 1982 /* 1983 * We snap the width of horizontal stems for the monochrome and 1984 * vertical LCD rendering targets only. 1985 */ 1986 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V ) 1987 other_flags |= AF_LATIN_HINTS_VERT_SNAP; 1988 1989 /* 1990 * We adjust stems to full pixels only if we don't use the `light' mode. 1991 */ 1992 if ( mode != FT_RENDER_MODE_LIGHT ) 1993 other_flags |= AF_LATIN_HINTS_STEM_ADJUST; 1994 1995 if ( mode == FT_RENDER_MODE_MONO ) 1996 other_flags |= AF_LATIN_HINTS_MONO; 1997 1998 /* 1999 * In `light' hinting mode we disable horizontal hinting completely. 2000 * We also do it if the face is italic. 2001 */ 2002 if ( mode == FT_RENDER_MODE_LIGHT || 2003 ( face->style_flags & FT_STYLE_FLAG_ITALIC ) != 0 ) 2004 scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL; 2005 2006 hints->scaler_flags = scaler_flags; 2007 hints->other_flags = other_flags; 2008 2009 return FT_Err_Ok; 2010 } 2011 2012 2013 /*************************************************************************/ 2014 /*************************************************************************/ 2015 /***** *****/ 2016 /***** L A T I N G L Y P H G R I D - F I T T I N G *****/ 2017 /***** *****/ 2018 /*************************************************************************/ 2019 /*************************************************************************/ 2020 2021 /* Snap a given width in scaled coordinates to one of the */ 2022 /* current standard widths. */ 2023 2024 static FT_Pos 2025 af_latin_snap_width( AF_Width widths, 2026 FT_Int count, 2027 FT_Pos width ) 2028 { 2029 int n; 2030 FT_Pos best = 64 + 32 + 2; 2031 FT_Pos reference = width; 2032 FT_Pos scaled; 2033 2034 2035 for ( n = 0; n < count; n++ ) 2036 { 2037 FT_Pos w; 2038 FT_Pos dist; 2039 2040 2041 w = widths[n].cur; 2042 dist = width - w; 2043 if ( dist < 0 ) 2044 dist = -dist; 2045 if ( dist < best ) 2046 { 2047 best = dist; 2048 reference = w; 2049 } 2050 } 2051 2052 scaled = FT_PIX_ROUND( reference ); 2053 2054 if ( width >= reference ) 2055 { 2056 if ( width < scaled + 48 ) 2057 width = reference; 2058 } 2059 else 2060 { 2061 if ( width > scaled - 48 ) 2062 width = reference; 2063 } 2064 2065 return width; 2066 } 2067 2068 2069 /* Compute the snapped width of a given stem, ignoring very thin ones. */ 2070 /* There is a lot of voodoo in this function; changing the hard-coded */ 2071 /* parameters influence the whole hinting process. */ 2072 2073 static FT_Pos 2074 af_latin_compute_stem_width( AF_GlyphHints hints, 2075 AF_Dimension dim, 2076 FT_Pos width, 2077 AF_Edge_Flags base_flags, 2078 AF_Edge_Flags stem_flags ) 2079 { 2080 AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics; 2081 AF_LatinAxis axis = &metrics->axis[dim]; 2082 FT_Pos dist = width; 2083 FT_Int sign = 0; 2084 FT_Int vertical = ( dim == AF_DIMENSION_VERT ); 2085 2086 2087 if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) || 2088 axis->extra_light ) 2089 return width; 2090 2091 if ( dist < 0 ) 2092 { 2093 dist = -width; 2094 sign = 1; 2095 } 2096 2097 if ( ( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) || 2098 ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) ) 2099 { 2100 /* smooth hinting process: very lightly quantize the stem width */ 2101 2102 /* leave the widths of serifs alone */ 2103 if ( ( stem_flags & AF_EDGE_SERIF ) && 2104 vertical && 2105 ( dist < 3 * 64 ) ) 2106 goto Done_Width; 2107 2108 else if ( base_flags & AF_EDGE_ROUND ) 2109 { 2110 if ( dist < 80 ) 2111 dist = 64; 2112 } 2113 else if ( dist < 56 ) 2114 dist = 56; 2115 2116 if ( axis->width_count > 0 ) 2117 { 2118 FT_Pos delta; 2119 2120 2121 /* compare to standard width */ 2122 delta = dist - axis->widths[0].cur; 2123 2124 if ( delta < 0 ) 2125 delta = -delta; 2126 2127 if ( delta < 40 ) 2128 { 2129 dist = axis->widths[0].cur; 2130 if ( dist < 48 ) 2131 dist = 48; 2132 2133 goto Done_Width; 2134 } 2135 2136 if ( dist < 3 * 64 ) 2137 { 2138 delta = dist & 63; 2139 dist &= -64; 2140 2141 if ( delta < 10 ) 2142 dist += delta; 2143 2144 else if ( delta < 32 ) 2145 dist += 10; 2146 2147 else if ( delta < 54 ) 2148 dist += 54; 2149 2150 else 2151 dist += delta; 2152 } 2153 else 2154 dist = ( dist + 32 ) & ~63; 2155 } 2156 } 2157 else 2158 { 2159 /* strong hinting process: snap the stem width to integer pixels */ 2160 2161 FT_Pos org_dist = dist; 2162 2163 2164 dist = af_latin_snap_width( axis->widths, axis->width_count, dist ); 2165 2166 if ( vertical ) 2167 { 2168 /* in the case of vertical hinting, always round */ 2169 /* the stem heights to integer pixels */ 2170 2171 if ( dist >= 64 ) 2172 dist = ( dist + 16 ) & ~63; 2173 else 2174 dist = 64; 2175 } 2176 else 2177 { 2178 if ( AF_LATIN_HINTS_DO_MONO( hints ) ) 2179 { 2180 /* monochrome horizontal hinting: snap widths to integer pixels */ 2181 /* with a different threshold */ 2182 2183 if ( dist < 64 ) 2184 dist = 64; 2185 else 2186 dist = ( dist + 32 ) & ~63; 2187 } 2188 else 2189 { 2190 /* for horizontal anti-aliased hinting, we adopt a more subtle */ 2191 /* approach: we strengthen small stems, round stems whose size */ 2192 /* is between 1 and 2 pixels to an integer, otherwise nothing */ 2193 2194 if ( dist < 48 ) 2195 dist = ( dist + 64 ) >> 1; 2196 2197 else if ( dist < 128 ) 2198 { 2199 /* We only round to an integer width if the corresponding */ 2200 /* distortion is less than 1/4 pixel. Otherwise this */ 2201 /* makes everything worse since the diagonals, which are */ 2202 /* not hinted, appear a lot bolder or thinner than the */ 2203 /* vertical stems. */ 2204 2205 FT_Pos delta; 2206 2207 2208 dist = ( dist + 22 ) & ~63; 2209 delta = dist - org_dist; 2210 if ( delta < 0 ) 2211 delta = -delta; 2212 2213 if ( delta >= 16 ) 2214 { 2215 dist = org_dist; 2216 if ( dist < 48 ) 2217 dist = ( dist + 64 ) >> 1; 2218 } 2219 } 2220 else 2221 /* round otherwise to prevent color fringes in LCD mode */ 2222 dist = ( dist + 32 ) & ~63; 2223 } 2224 } 2225 } 2226 2227 Done_Width: 2228 if ( sign ) 2229 dist = -dist; 2230 2231 return dist; 2232 } 2233 2234 2235 /* Align one stem edge relative to the previous stem edge. */ 2236 2237 static void 2238 af_latin_align_linked_edge( AF_GlyphHints hints, 2239 AF_Dimension dim, 2240 AF_Edge base_edge, 2241 AF_Edge stem_edge ) 2242 { 2243 FT_Pos dist = stem_edge->opos - base_edge->opos; 2244 2245 FT_Pos fitted_width = af_latin_compute_stem_width( 2246 hints, dim, dist, 2247 (AF_Edge_Flags)base_edge->flags, 2248 (AF_Edge_Flags)stem_edge->flags ); 2249 2250 2251 stem_edge->pos = base_edge->pos + fitted_width; 2252 2253 FT_TRACE5(( " LINK: edge %d (opos=%.2f) linked to %.2f," 2254 " dist was %.2f, now %.2f\n", 2255 stem_edge - hints->axis[dim].edges, stem_edge->opos / 64.0, 2256 stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 )); 2257 } 2258 2259 2260 /* Shift the coordinates of the `serif' edge by the same amount */ 2261 /* as the corresponding `base' edge has been moved already. */ 2262 2263 static void 2264 af_latin_align_serif_edge( AF_GlyphHints hints, 2265 AF_Edge base, 2266 AF_Edge serif ) 2267 { 2268 FT_UNUSED( hints ); 2269 2270 serif->pos = base->pos + ( serif->opos - base->opos ); 2271 } 2272 2273 2274 /*************************************************************************/ 2275 /*************************************************************************/ 2276 /*************************************************************************/ 2277 /**** ****/ 2278 /**** E D G E H I N T I N G ****/ 2279 /**** ****/ 2280 /*************************************************************************/ 2281 /*************************************************************************/ 2282 /*************************************************************************/ 2283 2284 2285 /* The main grid-fitting routine. */ 2286 2287 FT_LOCAL_DEF( void ) 2288 af_latin_hint_edges( AF_GlyphHints hints, 2289 AF_Dimension dim ) 2290 { 2291 AF_AxisHints axis = &hints->axis[dim]; 2292 AF_Edge edges = axis->edges; 2293 AF_Edge edge_limit = edges + axis->num_edges; 2294 FT_PtrDist n_edges; 2295 AF_Edge edge; 2296 AF_Edge anchor = NULL; 2297 FT_Int has_serifs = 0; 2298 2299 #ifdef FT_DEBUG_LEVEL_TRACE 2300 FT_UInt num_actions = 0; 2301 #endif 2302 2303 2304 FT_TRACE5(( "latin %s edge hinting (style `%s')\n", 2305 dim == AF_DIMENSION_VERT ? "horizontal" : "vertical", 2306 af_style_names[hints->metrics->style_class->style] )); 2307 2308 /* we begin by aligning all stems relative to the blue zone */ 2309 /* if needed -- that's only for horizontal edges */ 2310 2311 if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) ) 2312 { 2313 for ( edge = edges; edge < edge_limit; edge++ ) 2314 { 2315 AF_Width blue; 2316 AF_Edge edge1, edge2; /* these edges form the stem to check */ 2317 2318 2319 if ( edge->flags & AF_EDGE_DONE ) 2320 continue; 2321 2322 edge1 = NULL; 2323 edge2 = edge->link; 2324 2325 /* 2326 * If a stem contains both a neutral and a non-neutral blue zone, 2327 * skip the neutral one. Otherwise, outlines with different 2328 * directions might be incorrectly aligned at the same vertical 2329 * position. 2330 * 2331 * If we have two neutral blue zones, skip one of them. 2332 * 2333 */ 2334 if ( edge->blue_edge && edge2 && edge2->blue_edge ) 2335 { 2336 FT_Byte neutral = edge->flags & AF_EDGE_NEUTRAL; 2337 FT_Byte neutral2 = edge2->flags & AF_EDGE_NEUTRAL; 2338 2339 2340 if ( ( neutral && neutral2 ) || neutral2 ) 2341 { 2342 edge2->blue_edge = NULL; 2343 edge2->flags &= ~AF_EDGE_NEUTRAL; 2344 } 2345 else if ( neutral ) 2346 { 2347 edge->blue_edge = NULL; 2348 edge->flags &= ~AF_EDGE_NEUTRAL; 2349 } 2350 } 2351 2352 blue = edge->blue_edge; 2353 if ( blue ) 2354 edge1 = edge; 2355 2356 /* flip edges if the other edge is aligned to a blue zone */ 2357 else if ( edge2 && edge2->blue_edge ) 2358 { 2359 blue = edge2->blue_edge; 2360 edge1 = edge2; 2361 edge2 = edge; 2362 } 2363 2364 if ( !edge1 ) 2365 continue; 2366 2367 #ifdef FT_DEBUG_LEVEL_TRACE 2368 if ( !anchor ) 2369 FT_TRACE5(( " BLUE_ANCHOR: edge %d (opos=%.2f) snapped to %.2f," 2370 " was %.2f (anchor=edge %d)\n", 2371 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0, 2372 edge1->pos / 64.0, edge - edges )); 2373 else 2374 FT_TRACE5(( " BLUE: edge %d (opos=%.2f) snapped to %.2f," 2375 " was %.2f\n", 2376 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0, 2377 edge1->pos / 64.0 )); 2378 2379 num_actions++; 2380 #endif 2381 2382 edge1->pos = blue->fit; 2383 edge1->flags |= AF_EDGE_DONE; 2384 2385 if ( edge2 && !edge2->blue_edge ) 2386 { 2387 af_latin_align_linked_edge( hints, dim, edge1, edge2 ); 2388 edge2->flags |= AF_EDGE_DONE; 2389 2390 #ifdef FT_DEBUG_LEVEL_TRACE 2391 num_actions++; 2392 #endif 2393 } 2394 2395 if ( !anchor ) 2396 anchor = edge; 2397 } 2398 } 2399 2400 /* now we align all other stem edges, trying to maintain the */ 2401 /* relative order of stems in the glyph */ 2402 for ( edge = edges; edge < edge_limit; edge++ ) 2403 { 2404 AF_Edge edge2; 2405 2406 2407 if ( edge->flags & AF_EDGE_DONE ) 2408 continue; 2409 2410 /* skip all non-stem edges */ 2411 edge2 = edge->link; 2412 if ( !edge2 ) 2413 { 2414 has_serifs++; 2415 continue; 2416 } 2417 2418 /* now align the stem */ 2419 2420 /* this should not happen, but it's better to be safe */ 2421 if ( edge2->blue_edge ) 2422 { 2423 FT_TRACE5(( " ASSERTION FAILED for edge %d\n", edge2 - edges )); 2424 2425 af_latin_align_linked_edge( hints, dim, edge2, edge ); 2426 edge->flags |= AF_EDGE_DONE; 2427 2428 #ifdef FT_DEBUG_LEVEL_TRACE 2429 num_actions++; 2430 #endif 2431 continue; 2432 } 2433 2434 if ( !anchor ) 2435 { 2436 /* if we reach this if clause, no stem has been aligned yet */ 2437 2438 FT_Pos org_len, org_center, cur_len; 2439 FT_Pos cur_pos1, error1, error2, u_off, d_off; 2440 2441 2442 org_len = edge2->opos - edge->opos; 2443 cur_len = af_latin_compute_stem_width( 2444 hints, dim, org_len, 2445 (AF_Edge_Flags)edge->flags, 2446 (AF_Edge_Flags)edge2->flags ); 2447 2448 /* some voodoo to specially round edges for small stem widths; */ 2449 /* the idea is to align the center of a stem, then shifting */ 2450 /* the stem edges to suitable positions */ 2451 if ( cur_len <= 64 ) 2452 { 2453 /* width <= 1px */ 2454 u_off = 32; 2455 d_off = 32; 2456 } 2457 else 2458 { 2459 /* 1px < width < 1.5px */ 2460 u_off = 38; 2461 d_off = 26; 2462 } 2463 2464 if ( cur_len < 96 ) 2465 { 2466 org_center = edge->opos + ( org_len >> 1 ); 2467 cur_pos1 = FT_PIX_ROUND( org_center ); 2468 2469 error1 = org_center - ( cur_pos1 - u_off ); 2470 if ( error1 < 0 ) 2471 error1 = -error1; 2472 2473 error2 = org_center - ( cur_pos1 + d_off ); 2474 if ( error2 < 0 ) 2475 error2 = -error2; 2476 2477 if ( error1 < error2 ) 2478 cur_pos1 -= u_off; 2479 else 2480 cur_pos1 += d_off; 2481 2482 edge->pos = cur_pos1 - cur_len / 2; 2483 edge2->pos = edge->pos + cur_len; 2484 } 2485 else 2486 edge->pos = FT_PIX_ROUND( edge->opos ); 2487 2488 anchor = edge; 2489 edge->flags |= AF_EDGE_DONE; 2490 2491 FT_TRACE5(( " ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f)" 2492 " snapped to %.2f and %.2f\n", 2493 edge - edges, edge->opos / 64.0, 2494 edge2 - edges, edge2->opos / 64.0, 2495 edge->pos / 64.0, edge2->pos / 64.0 )); 2496 2497 af_latin_align_linked_edge( hints, dim, edge, edge2 ); 2498 2499 #ifdef FT_DEBUG_LEVEL_TRACE 2500 num_actions += 2; 2501 #endif 2502 } 2503 else 2504 { 2505 FT_Pos org_pos, org_len, org_center, cur_len; 2506 FT_Pos cur_pos1, cur_pos2, delta1, delta2; 2507 2508 2509 org_pos = anchor->pos + ( edge->opos - anchor->opos ); 2510 org_len = edge2->opos - edge->opos; 2511 org_center = org_pos + ( org_len >> 1 ); 2512 2513 cur_len = af_latin_compute_stem_width( 2514 hints, dim, org_len, 2515 (AF_Edge_Flags)edge->flags, 2516 (AF_Edge_Flags)edge2->flags ); 2517 2518 if ( edge2->flags & AF_EDGE_DONE ) 2519 { 2520 FT_TRACE5(( " ADJUST: edge %d (pos=%.2f) moved to %.2f\n", 2521 edge - edges, edge->pos / 64.0, 2522 ( edge2->pos - cur_len ) / 64.0 )); 2523 2524 edge->pos = edge2->pos - cur_len; 2525 } 2526 2527 else if ( cur_len < 96 ) 2528 { 2529 FT_Pos u_off, d_off; 2530 2531 2532 cur_pos1 = FT_PIX_ROUND( org_center ); 2533 2534 if ( cur_len <= 64 ) 2535 { 2536 u_off = 32; 2537 d_off = 32; 2538 } 2539 else 2540 { 2541 u_off = 38; 2542 d_off = 26; 2543 } 2544 2545 delta1 = org_center - ( cur_pos1 - u_off ); 2546 if ( delta1 < 0 ) 2547 delta1 = -delta1; 2548 2549 delta2 = org_center - ( cur_pos1 + d_off ); 2550 if ( delta2 < 0 ) 2551 delta2 = -delta2; 2552 2553 if ( delta1 < delta2 ) 2554 cur_pos1 -= u_off; 2555 else 2556 cur_pos1 += d_off; 2557 2558 edge->pos = cur_pos1 - cur_len / 2; 2559 edge2->pos = cur_pos1 + cur_len / 2; 2560 2561 FT_TRACE5(( " STEM: edge %d (opos=%.2f) linked to %d (opos=%.2f)" 2562 " snapped to %.2f and %.2f\n", 2563 edge - edges, edge->opos / 64.0, 2564 edge2 - edges, edge2->opos / 64.0, 2565 edge->pos / 64.0, edge2->pos / 64.0 )); 2566 } 2567 2568 else 2569 { 2570 org_pos = anchor->pos + ( edge->opos - anchor->opos ); 2571 org_len = edge2->opos - edge->opos; 2572 org_center = org_pos + ( org_len >> 1 ); 2573 2574 cur_len = af_latin_compute_stem_width( 2575 hints, dim, org_len, 2576 (AF_Edge_Flags)edge->flags, 2577 (AF_Edge_Flags)edge2->flags ); 2578 2579 cur_pos1 = FT_PIX_ROUND( org_pos ); 2580 delta1 = cur_pos1 + ( cur_len >> 1 ) - org_center; 2581 if ( delta1 < 0 ) 2582 delta1 = -delta1; 2583 2584 cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len; 2585 delta2 = cur_pos2 + ( cur_len >> 1 ) - org_center; 2586 if ( delta2 < 0 ) 2587 delta2 = -delta2; 2588 2589 edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2; 2590 edge2->pos = edge->pos + cur_len; 2591 2592 FT_TRACE5(( " STEM: edge %d (opos=%.2f) linked to %d (opos=%.2f)" 2593 " snapped to %.2f and %.2f\n", 2594 edge - edges, edge->opos / 64.0, 2595 edge2 - edges, edge2->opos / 64.0, 2596 edge->pos / 64.0, edge2->pos / 64.0 )); 2597 } 2598 2599 #ifdef FT_DEBUG_LEVEL_TRACE 2600 num_actions++; 2601 #endif 2602 2603 edge->flags |= AF_EDGE_DONE; 2604 edge2->flags |= AF_EDGE_DONE; 2605 2606 if ( edge > edges && edge->pos < edge[-1].pos ) 2607 { 2608 #ifdef FT_DEBUG_LEVEL_TRACE 2609 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n", 2610 edge - edges, edge->pos / 64.0, edge[-1].pos / 64.0 )); 2611 2612 num_actions++; 2613 #endif 2614 2615 edge->pos = edge[-1].pos; 2616 } 2617 } 2618 } 2619 2620 /* make sure that lowercase m's maintain their symmetry */ 2621 2622 /* In general, lowercase m's have six vertical edges if they are sans */ 2623 /* serif, or twelve if they are with serifs. This implementation is */ 2624 /* based on that assumption, and seems to work very well with most */ 2625 /* faces. However, if for a certain face this assumption is not */ 2626 /* true, the m is just rendered like before. In addition, any stem */ 2627 /* correction will only be applied to symmetrical glyphs (even if the */ 2628 /* glyph is not an m), so the potential for unwanted distortion is */ 2629 /* relatively low. */ 2630 2631 /* We don't handle horizontal edges since we can't easily assure that */ 2632 /* the third (lowest) stem aligns with the base line; it might end up */ 2633 /* one pixel higher or lower. */ 2634 2635 n_edges = edge_limit - edges; 2636 if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) ) 2637 { 2638 AF_Edge edge1, edge2, edge3; 2639 FT_Pos dist1, dist2, span, delta; 2640 2641 2642 if ( n_edges == 6 ) 2643 { 2644 edge1 = edges; 2645 edge2 = edges + 2; 2646 edge3 = edges + 4; 2647 } 2648 else 2649 { 2650 edge1 = edges + 1; 2651 edge2 = edges + 5; 2652 edge3 = edges + 9; 2653 } 2654 2655 dist1 = edge2->opos - edge1->opos; 2656 dist2 = edge3->opos - edge2->opos; 2657 2658 span = dist1 - dist2; 2659 if ( span < 0 ) 2660 span = -span; 2661 2662 if ( span < 8 ) 2663 { 2664 delta = edge3->pos - ( 2 * edge2->pos - edge1->pos ); 2665 edge3->pos -= delta; 2666 if ( edge3->link ) 2667 edge3->link->pos -= delta; 2668 2669 /* move the serifs along with the stem */ 2670 if ( n_edges == 12 ) 2671 { 2672 ( edges + 8 )->pos -= delta; 2673 ( edges + 11 )->pos -= delta; 2674 } 2675 2676 edge3->flags |= AF_EDGE_DONE; 2677 if ( edge3->link ) 2678 edge3->link->flags |= AF_EDGE_DONE; 2679 } 2680 } 2681 2682 if ( has_serifs || !anchor ) 2683 { 2684 /* 2685 * now hint the remaining edges (serifs and single) in order 2686 * to complete our processing 2687 */ 2688 for ( edge = edges; edge < edge_limit; edge++ ) 2689 { 2690 FT_Pos delta; 2691 2692 2693 if ( edge->flags & AF_EDGE_DONE ) 2694 continue; 2695 2696 delta = 1000; 2697 2698 if ( edge->serif ) 2699 { 2700 delta = edge->serif->opos - edge->opos; 2701 if ( delta < 0 ) 2702 delta = -delta; 2703 } 2704 2705 if ( delta < 64 + 16 ) 2706 { 2707 af_latin_align_serif_edge( hints, edge->serif, edge ); 2708 FT_TRACE5(( " SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f)" 2709 " aligned to %.2f\n", 2710 edge - edges, edge->opos / 64.0, 2711 edge->serif - edges, edge->serif->opos / 64.0, 2712 edge->pos / 64.0 )); 2713 } 2714 else if ( !anchor ) 2715 { 2716 edge->pos = FT_PIX_ROUND( edge->opos ); 2717 anchor = edge; 2718 FT_TRACE5(( " SERIF_ANCHOR: edge %d (opos=%.2f)" 2719 " snapped to %.2f\n", 2720 edge-edges, edge->opos / 64.0, edge->pos / 64.0 )); 2721 } 2722 else 2723 { 2724 AF_Edge before, after; 2725 2726 2727 for ( before = edge - 1; before >= edges; before-- ) 2728 if ( before->flags & AF_EDGE_DONE ) 2729 break; 2730 2731 for ( after = edge + 1; after < edge_limit; after++ ) 2732 if ( after->flags & AF_EDGE_DONE ) 2733 break; 2734 2735 if ( before >= edges && before < edge && 2736 after < edge_limit && after > edge ) 2737 { 2738 if ( after->opos == before->opos ) 2739 edge->pos = before->pos; 2740 else 2741 edge->pos = before->pos + 2742 FT_MulDiv( edge->opos - before->opos, 2743 after->pos - before->pos, 2744 after->opos - before->opos ); 2745 2746 FT_TRACE5(( " SERIF_LINK1: edge %d (opos=%.2f) snapped to %.2f" 2747 " from %d (opos=%.2f)\n", 2748 edge - edges, edge->opos / 64.0, 2749 edge->pos / 64.0, 2750 before - edges, before->opos / 64.0 )); 2751 } 2752 else 2753 { 2754 edge->pos = anchor->pos + 2755 ( ( edge->opos - anchor->opos + 16 ) & ~31 ); 2756 FT_TRACE5(( " SERIF_LINK2: edge %d (opos=%.2f)" 2757 " snapped to %.2f\n", 2758 edge - edges, edge->opos / 64.0, edge->pos / 64.0 )); 2759 } 2760 } 2761 2762 #ifdef FT_DEBUG_LEVEL_TRACE 2763 num_actions++; 2764 #endif 2765 edge->flags |= AF_EDGE_DONE; 2766 2767 if ( edge > edges && edge->pos < edge[-1].pos ) 2768 { 2769 #ifdef FT_DEBUG_LEVEL_TRACE 2770 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n", 2771 edge - edges, edge->pos / 64.0, edge[-1].pos / 64.0 )); 2772 2773 num_actions++; 2774 #endif 2775 edge->pos = edge[-1].pos; 2776 } 2777 2778 if ( edge + 1 < edge_limit && 2779 edge[1].flags & AF_EDGE_DONE && 2780 edge->pos > edge[1].pos ) 2781 { 2782 #ifdef FT_DEBUG_LEVEL_TRACE 2783 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n", 2784 edge - edges, edge->pos / 64.0, edge[1].pos / 64.0 )); 2785 2786 num_actions++; 2787 #endif 2788 2789 edge->pos = edge[1].pos; 2790 } 2791 } 2792 } 2793 2794 #ifdef FT_DEBUG_LEVEL_TRACE 2795 if ( !num_actions ) 2796 FT_TRACE5(( " (none)\n" )); 2797 FT_TRACE5(( "\n" )); 2798 #endif 2799 } 2800 2801 2802 /* Apply the complete hinting algorithm to a latin glyph. */ 2803 2804 static FT_Error 2805 af_latin_hints_apply( AF_GlyphHints hints, 2806 FT_Outline* outline, 2807 AF_LatinMetrics metrics ) 2808 { 2809 FT_Error error; 2810 int dim; 2811 2812 AF_LatinAxis axis; 2813 2814 2815 error = af_glyph_hints_reload( hints, outline ); 2816 if ( error ) 2817 goto Exit; 2818 2819 /* analyze glyph outline */ 2820 #ifdef AF_CONFIG_OPTION_USE_WARPER 2821 if ( metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT || 2822 AF_HINTS_DO_HORIZONTAL( hints ) ) 2823 #else 2824 if ( AF_HINTS_DO_HORIZONTAL( hints ) ) 2825 #endif 2826 { 2827 axis = &metrics->axis[AF_DIMENSION_HORZ]; 2828 error = af_latin_hints_detect_features( hints, 2829 axis->width_count, 2830 axis->widths, 2831 AF_DIMENSION_HORZ ); 2832 if ( error ) 2833 goto Exit; 2834 } 2835 2836 if ( AF_HINTS_DO_VERTICAL( hints ) ) 2837 { 2838 axis = &metrics->axis[AF_DIMENSION_VERT]; 2839 error = af_latin_hints_detect_features( hints, 2840 axis->width_count, 2841 axis->widths, 2842 AF_DIMENSION_VERT ); 2843 if ( error ) 2844 goto Exit; 2845 2846 af_latin_hints_compute_blue_edges( hints, metrics ); 2847 } 2848 2849 /* grid-fit the outline */ 2850 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) 2851 { 2852 #ifdef AF_CONFIG_OPTION_USE_WARPER 2853 if ( dim == AF_DIMENSION_HORZ && 2854 metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT ) 2855 { 2856 AF_WarperRec warper; 2857 FT_Fixed scale; 2858 FT_Pos delta; 2859 2860 2861 af_warper_compute( &warper, hints, (AF_Dimension)dim, 2862 &scale, &delta ); 2863 af_glyph_hints_scale_dim( hints, (AF_Dimension)dim, 2864 scale, delta ); 2865 continue; 2866 } 2867 #endif 2868 2869 if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) || 2870 ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) ) ) 2871 { 2872 af_latin_hint_edges( hints, (AF_Dimension)dim ); 2873 af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim ); 2874 af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim ); 2875 af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim ); 2876 } 2877 } 2878 2879 af_glyph_hints_save( hints, outline ); 2880 2881 Exit: 2882 return error; 2883 } 2884 2885 2886 /*************************************************************************/ 2887 /*************************************************************************/ 2888 /***** *****/ 2889 /***** L A T I N S C R I P T C L A S S *****/ 2890 /***** *****/ 2891 /*************************************************************************/ 2892 /*************************************************************************/ 2893 2894 2895 AF_DEFINE_WRITING_SYSTEM_CLASS( 2896 af_latin_writing_system_class, 2897 2898 AF_WRITING_SYSTEM_LATIN, 2899 2900 sizeof ( AF_LatinMetricsRec ), 2901 2902 (AF_WritingSystem_InitMetricsFunc) af_latin_metrics_init, 2903 (AF_WritingSystem_ScaleMetricsFunc)af_latin_metrics_scale, 2904 (AF_WritingSystem_DoneMetricsFunc) NULL, 2905 2906 (AF_WritingSystem_InitHintsFunc) af_latin_hints_init, 2907 (AF_WritingSystem_ApplyHintsFunc) af_latin_hints_apply 2908 ) 2909 2910 2911 /* END */ 2912
