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