1 /****************************************************************************
2 *
3 * aflatin.c
4 *
5 * Auto-fitter hinting routines for latin writing system (body).
6 *
7 * Copyright (C) 2003-2019 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 "aflatin.h"
25 #include "aferrors.h"
26
27
28 #ifdef AF_CONFIG_OPTION_USE_WARPER
29 #include "afwarp.h"
30 #endif
31
32
33 /**************************************************************************
34 *
35 * The macro FT_COMPONENT is used in trace mode. It is an implicit
36 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
37 * messages during execution.
38 */
39 #undef FT_COMPONENT
40 #define FT_COMPONENT aflatin
41
42
43 /* needed for computation of round vs. flat segments */
44 #define FLAT_THRESHOLD( x ) ( x / 14 )
45
46
47 /*************************************************************************/
48 /*************************************************************************/
49 /***** *****/
50 /***** L A T I N G L O B A L M E T R I C S *****/
51 /***** *****/
52 /*************************************************************************/
53 /*************************************************************************/
54
55
56 /* Find segments and links, compute all stem widths, and initialize */
57 /* standard width and height for the glyph with given charcode. */
58
59 FT_LOCAL_DEF( void )
60 af_latin_metrics_init_widths( AF_LatinMetrics metrics,
61 FT_Face face )
62 {
63 /* scan the array of segments in each direction */
64 AF_GlyphHintsRec hints[1];
65
66
67 FT_TRACE5(( "\n"
68 "latin standard widths computation (style `%s')\n"
69 "=====================================================\n"
70 "\n",
71 af_style_names[metrics->root.style_class->style] ));
72
73 af_glyph_hints_init( hints, face->memory );
74
75 metrics->axis[AF_DIMENSION_HORZ].width_count = 0;
76 metrics->axis[AF_DIMENSION_VERT].width_count = 0;
77
78 {
79 FT_Error error;
80 FT_ULong glyph_index;
81 int dim;
82 AF_LatinMetricsRec dummy[1];
83 AF_Scaler scaler = &dummy->root.scaler;
84
85 AF_StyleClass style_class = metrics->root.style_class;
86 AF_ScriptClass script_class = af_script_classes[style_class->script];
87
88 /* If HarfBuzz is not available, we need a pointer to a single */
89 /* unsigned long value. */
90 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
91 void* shaper_buf;
92 #else
93 FT_ULong shaper_buf_;
94 void* shaper_buf = &shaper_buf_;
95 #endif
96
97 const char* p;
98
99 #ifdef FT_DEBUG_LEVEL_TRACE
100 FT_ULong ch = 0;
101 #endif
102
103
104 p = script_class->standard_charstring;
105
106 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
107 shaper_buf = af_shaper_buf_create( face );
108 #endif
109 /*
110 * We check a list of standard characters to catch features like
111 * `c2sc' (small caps from caps) that don't contain lowercase letters
112 * by definition, or other features that mainly operate on numerals.
113 * The first match wins.
114 */
115
116 glyph_index = 0;
117 while ( *p )
118 {
119 unsigned int num_idx;
120
121 #ifdef FT_DEBUG_LEVEL_TRACE
122 const char* p_old;
123 #endif
124
125
126 while ( *p == ' ' )
127 p++;
128
129 #ifdef FT_DEBUG_LEVEL_TRACE
130 p_old = p;
131 GET_UTF8_CHAR( ch, p_old );
132 #endif
133
134 /* reject input that maps to more than a single glyph */
135 p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx );
136 if ( num_idx > 1 )
137 continue;
138
139 /* otherwise exit loop if we have a result */
140 glyph_index = af_shaper_get_elem( &metrics->root,
141 shaper_buf,
142 0,
143 NULL,
144 NULL );
145 if ( glyph_index )
146 break;
147 }
148
149 af_shaper_buf_destroy( face, shaper_buf );
150
151 if ( !glyph_index )
152 {
153 FT_TRACE5(( "standard character missing;"
154 " using fallback stem widths\n" ));
155 goto Exit;
156 }
157
158 FT_TRACE5(( "standard character: U+%04lX (glyph index %d)\n",
159 ch, glyph_index ));
160
161 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
162 if ( error || face->glyph->outline.n_points <= 0 )
163 goto Exit;
164
165 FT_ZERO( dummy );
166
167 dummy->units_per_em = metrics->units_per_em;
168
169 scaler->x_scale = 0x10000L;
170 scaler->y_scale = 0x10000L;
171 scaler->x_delta = 0;
172 scaler->y_delta = 0;
173
174 scaler->face = face;
175 scaler->render_mode = FT_RENDER_MODE_NORMAL;
176 scaler->flags = 0;
177
178 af_glyph_hints_rescale( hints, (AF_StyleMetrics)dummy );
179
180 error = af_glyph_hints_reload( hints, &face->glyph->outline );
181 if ( error )
182 goto Exit;
183
184 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
185 {
186 AF_LatinAxis axis = &metrics->axis[dim];
187 AF_AxisHints axhints = &hints->axis[dim];
188 AF_Segment seg, limit, link;
189 FT_UInt num_widths = 0;
190
191
192 error = af_latin_hints_compute_segments( hints,
193 (AF_Dimension)dim );
194 if ( error )
195 goto Exit;
196
197 /*
198 * We assume that the glyphs selected for the stem width
199 * computation are `featureless' enough so that the linking
200 * algorithm works fine without adjustments of its scoring
201 * function.
202 */
203 af_latin_hints_link_segments( hints,
204 0,
205 NULL,
206 (AF_Dimension)dim );
207
208 seg = axhints->segments;
209 limit = seg + axhints->num_segments;
210
211 for ( ; seg < limit; seg++ )
212 {
213 link = seg->link;
214
215 /* we only consider stem segments there! */
216 if ( link && link->link == seg && link > seg )
217 {
218 FT_Pos dist;
219
220
221 dist = seg->pos - link->pos;
222 if ( dist < 0 )
223 dist = -dist;
224
225 if ( num_widths < AF_LATIN_MAX_WIDTHS )
226 axis->widths[num_widths++].org = dist;
227 }
228 }
229
230 /* this also replaces multiple almost identical stem widths */
231 /* with a single one (the value 100 is heuristic) */
232 af_sort_and_quantize_widths( &num_widths, axis->widths,
233 dummy->units_per_em / 100 );
234 axis->width_count = num_widths;
235 }
236
237 Exit:
238 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
239 {
240 AF_LatinAxis axis = &metrics->axis[dim];
241 FT_Pos stdw;
242
243
244 stdw = ( axis->width_count > 0 ) ? axis->widths[0].org
245 : AF_LATIN_CONSTANT( metrics, 50 );
246
247 /* let's try 20% of the smallest width */
248 axis->edge_distance_threshold = stdw / 5;
249 axis->standard_width = stdw;
250 axis->extra_light = 0;
251
252 #ifdef FT_DEBUG_LEVEL_TRACE
253 {
254 FT_UInt i;
255
256
257 FT_TRACE5(( "%s widths:\n",
258 dim == AF_DIMENSION_VERT ? "horizontal"
259 : "vertical" ));
260
261 FT_TRACE5(( " %d (standard)", axis->standard_width ));
262 for ( i = 1; i < axis->width_count; i++ )
263 FT_TRACE5(( " %d", axis->widths[i].org ));
264
265 FT_TRACE5(( "\n" ));
266 }
267 #endif
268 }
269 }
270
271 FT_TRACE5(( "\n" ));
272
273 af_glyph_hints_done( hints );
274 }
275
276
277 static void
278 af_latin_sort_blue( FT_UInt count,
279 AF_LatinBlue* table )
280 {
281 FT_UInt i, j;
282 AF_LatinBlue swap;
283
284
285 /* we sort from bottom to top */
286 for ( i = 1; i < count; i++ )
287 {
288 for ( j = i; j > 0; j-- )
289 {
290 FT_Pos a, b;
291
292
293 if ( table[j - 1]->flags & ( AF_LATIN_BLUE_TOP |
294 AF_LATIN_BLUE_SUB_TOP ) )
295 a = table[j - 1]->ref.org;
296 else
297 a = table[j - 1]->shoot.org;
298
299 if ( table[j]->flags & ( AF_LATIN_BLUE_TOP |
300 AF_LATIN_BLUE_SUB_TOP ) )
301 b = table[j]->ref.org;
302 else
303 b = table[j]->shoot.org;
304
305 if ( b >= a )
306 break;
307
308 swap = table[j];
309 table[j] = table[j - 1];
310 table[j - 1] = swap;
311 }
312 }
313 }
314
315
316 /* Find all blue zones. Flat segments give the reference points, */
317 /* round segments the overshoot positions. */
318
319 static int
320 af_latin_metrics_init_blues( AF_LatinMetrics metrics,
321 FT_Face face )
322 {
323 FT_Pos flats [AF_BLUE_STRING_MAX_LEN];
324 FT_Pos rounds[AF_BLUE_STRING_MAX_LEN];
325
326 FT_UInt num_flats;
327 FT_UInt num_rounds;
328
329 AF_LatinBlue blue;
330 FT_Error error;
331 AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT];
332 FT_Outline outline;
333
334 AF_StyleClass sc = metrics->root.style_class;
335
336 AF_Blue_Stringset bss = sc->blue_stringset;
337 const AF_Blue_StringRec* bs = &af_blue_stringsets[bss];
338
339 FT_Pos flat_threshold = FLAT_THRESHOLD( metrics->units_per_em );
340
341 /* If HarfBuzz is not available, we need a pointer to a single */
342 /* unsigned long value. */
343 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
344 void* shaper_buf;
345 #else
346 FT_ULong shaper_buf_;
347 void* shaper_buf = &shaper_buf_;
348 #endif
349
350
351 /* we walk over the blue character strings as specified in the */
352 /* style's entry in the `af_blue_stringset' array */
353
354 FT_TRACE5(( "latin blue zones computation\n"
355 "============================\n"
356 "\n" ));
357
358 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
359 shaper_buf = af_shaper_buf_create( face );
360 #endif
361
362 for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ )
363 {
364 const char* p = &af_blue_strings[bs->string];
365 FT_Pos* blue_ref;
366 FT_Pos* blue_shoot;
367 FT_Pos ascender;
368 FT_Pos descender;
369
370
371 #ifdef FT_DEBUG_LEVEL_TRACE
372 {
373 FT_Bool have_flag = 0;
374
375
376 FT_TRACE5(( "blue zone %d", axis->blue_count ));
377
378 if ( bs->properties )
379 {
380 FT_TRACE5(( " (" ));
381
382 if ( AF_LATIN_IS_TOP_BLUE( bs ) )
383 {
384 FT_TRACE5(( "top" ));
385 have_flag = 1;
386 }
387 else if ( AF_LATIN_IS_SUB_TOP_BLUE( bs ) )
388 {
389 FT_TRACE5(( "sub top" ));
390 have_flag = 1;
391 }
392
393 if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) )
394 {
395 if ( have_flag )
396 FT_TRACE5(( ", " ));
397 FT_TRACE5(( "neutral" ));
398 have_flag = 1;
399 }
400
401 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) )
402 {
403 if ( have_flag )
404 FT_TRACE5(( ", " ));
405 FT_TRACE5(( "small top" ));
406 have_flag = 1;
407 }
408
409 if ( AF_LATIN_IS_LONG_BLUE( bs ) )
410 {
411 if ( have_flag )
412 FT_TRACE5(( ", " ));
413 FT_TRACE5(( "long" ));
414 }
415
416 FT_TRACE5(( ")" ));
417 }
418
419 FT_TRACE5(( ":\n" ));
420 }
421 #endif /* FT_DEBUG_LEVEL_TRACE */
422
423 num_flats = 0;
424 num_rounds = 0;
425 ascender = 0;
426 descender = 0;
427
428 while ( *p )
429 {
430 FT_ULong glyph_index;
431 FT_Long y_offset;
432 FT_Int best_point, best_contour_first, best_contour_last;
433 FT_Vector* points;
434
435 FT_Pos best_y_extremum; /* same as points.y */
436 FT_Bool best_round = 0;
437
438 unsigned int i, num_idx;
439
440 #ifdef FT_DEBUG_LEVEL_TRACE
441 const char* p_old;
442 FT_ULong ch;
443 #endif
444
445
446 while ( *p == ' ' )
447 p++;
448
449 #ifdef FT_DEBUG_LEVEL_TRACE
450 p_old = p;
451 GET_UTF8_CHAR( ch, p_old );
452 #endif
453
454 p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx );
455
456 if ( !num_idx )
457 {
458 FT_TRACE5(( " U+%04lX unavailable\n", ch ));
459 continue;
460 }
461
462 if ( AF_LATIN_IS_TOP_BLUE( bs ) )
463 best_y_extremum = FT_INT_MIN;
464 else
465 best_y_extremum = FT_INT_MAX;
466
467 /* iterate over all glyph elements of the character cluster */
468 /* and get the data of the `biggest' one */
469 for ( i = 0; i < num_idx; i++ )
470 {
471 FT_Pos best_y;
472 FT_Bool round = 0;
473
474
475 /* load the character in the face -- skip unknown or empty ones */
476 glyph_index = af_shaper_get_elem( &metrics->root,
477 shaper_buf,
478 i,
479 NULL,
480 &y_offset );
481 if ( glyph_index == 0 )
482 {
483 FT_TRACE5(( " U+%04lX unavailable\n", ch ));
484 continue;
485 }
486
487 error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
488 outline = face->glyph->outline;
489 /* reject glyphs that don't produce any rendering */
490 if ( error || outline.n_points <= 2 )
491 {
492 #ifdef FT_DEBUG_LEVEL_TRACE
493 if ( num_idx == 1 )
494 FT_TRACE5(( " U+%04lX contains no (usable) outlines\n", ch ));
495 else
496 FT_TRACE5(( " component %d of cluster starting with U+%04lX"
497 " contains no (usable) outlines\n", i, ch ));
498 #endif
499 continue;
500 }
501
502 /* now compute min or max point indices and coordinates */
503 points = outline.points;
504 best_point = -1;
505 best_y = 0; /* make compiler happy */
506 best_contour_first = 0; /* ditto */
507 best_contour_last = 0; /* ditto */
508
509 {
510 FT_Int nn;
511 FT_Int first = 0;
512 FT_Int last = -1;
513
514
515 for ( nn = 0; nn < outline.n_contours; first = last + 1, nn++ )
516 {
517 FT_Int old_best_point = best_point;
518 FT_Int pp;
519
520
521 last = outline.contours[nn];
522
523 /* Avoid single-point contours since they are never */
524 /* rasterized. In some fonts, they correspond to mark */
525 /* attachment points that are way outside of the glyph's */
526 /* real outline. */
527 if ( last <= first )
528 continue;
529
530 if ( AF_LATIN_IS_TOP_BLUE( bs ) ||
531 AF_LATIN_IS_SUB_TOP_BLUE( bs ) )
532 {
533 for ( pp = first; pp <= last; pp++ )
534 {
535 if ( best_point < 0 || points[pp].y > best_y )
536 {
537 best_point = pp;
538 best_y = points[pp].y;
539 ascender = FT_MAX( ascender, best_y + y_offset );
540 }
541 else
542 descender = FT_MIN( descender, points[pp].y + y_offset );
543 }
544 }
545 else
546 {
547 for ( pp = first; pp <= last; pp++ )
548 {
549 if ( best_point < 0 || points[pp].y < best_y )
550 {
551 best_point = pp;
552 best_y = points[pp].y;
553 descender = FT_MIN( descender, best_y + y_offset );
554 }
555 else
556 ascender = FT_MAX( ascender, points[pp].y + y_offset );
557 }
558 }
559
560 if ( best_point != old_best_point )
561 {
562 best_contour_first = first;
563 best_contour_last = last;
564 }
565 }
566 }
567
568 /* now check whether the point belongs to a straight or round */
569 /* segment; we first need to find in which contour the extremum */
570 /* lies, then inspect its previous and next points */
571 if ( best_point >= 0 )
572 {
573 FT_Pos best_x = points[best_point].x;
574 FT_Int prev, next;
575 FT_Int best_segment_first, best_segment_last;
576 FT_Int best_on_point_first, best_on_point_last;
577 FT_Pos dist;
578
579
580 best_segment_first = best_point;
581 best_segment_last = best_point;
582
583 if ( FT_CURVE_TAG( outline.tags[best_point] ) == FT_CURVE_TAG_ON )
584 {
585 best_on_point_first = best_point;
586 best_on_point_last = best_point;
587 }
588 else
589 {
590 best_on_point_first = -1;
591 best_on_point_last = -1;
592 }
593
594 /* look for the previous and next points on the contour */
595 /* that are not on the same Y coordinate, then threshold */
596 /* the `closeness'... */
597 prev = best_point;
598 next = prev;
599
600 do
601 {
602 if ( prev > best_contour_first )
603 prev--;
604 else
605 prev = best_contour_last;
606
607 dist = FT_ABS( points[prev].y - best_y );
608 /* accept a small distance or a small angle (both values are */
609 /* heuristic; value 20 corresponds to approx. 2.9 degrees) */
610 if ( dist > 5 )
611 if ( FT_ABS( points[prev].x - best_x ) <= 20 * dist )
612 break;
613
614 best_segment_first = prev;
615
616 if ( FT_CURVE_TAG( outline.tags[prev] ) == FT_CURVE_TAG_ON )
617 {
618 best_on_point_first = prev;
619 if ( best_on_point_last < 0 )
620 best_on_point_last = prev;
621 }
622
623 } while ( prev != best_point );
624
625 do
626 {
627 if ( next < best_contour_last )
628 next++;
629 else
630 next = best_contour_first;
631
632 dist = FT_ABS( points[next].y - best_y );
633 if ( dist > 5 )
634 if ( FT_ABS( points[next].x - best_x ) <= 20 * dist )
635 break;
636
637 best_segment_last = next;
638
639 if ( FT_CURVE_TAG( outline.tags[next] ) == FT_CURVE_TAG_ON )
640 {
641 best_on_point_last = next;
642 if ( best_on_point_first < 0 )
643 best_on_point_first = next;
644 }
645
646 } while ( next != best_point );
647
648 if ( AF_LATIN_IS_LONG_BLUE( bs ) )
649 {
650 /* If this flag is set, we have an additional constraint to */
651 /* get the blue zone distance: Find a segment of the topmost */
652 /* (or bottommost) contour that is longer than a heuristic */
653 /* threshold. This ensures that small bumps in the outline */
654 /* are ignored (for example, the `vertical serifs' found in */
655 /* many Hebrew glyph designs). */
656
657 /* If this segment is long enough, we are done. Otherwise, */
658 /* search the segment next to the extremum that is long */
659 /* enough, has the same direction, and a not too large */
660 /* vertical distance from the extremum. Note that the */
661 /* algorithm doesn't check whether the found segment is */
662 /* actually the one (vertically) nearest to the extremum. */
663
664 /* heuristic threshold value */
665 FT_Pos length_threshold = metrics->units_per_em / 25;
666
667
668 dist = FT_ABS( points[best_segment_last].x -
669 points[best_segment_first].x );
670
671 if ( dist < length_threshold &&
672 best_segment_last - best_segment_first + 2 <=
673 best_contour_last - best_contour_first )
674 {
675 /* heuristic threshold value */
676 FT_Pos height_threshold = metrics->units_per_em / 4;
677
678 FT_Int first;
679 FT_Int last;
680 FT_Bool hit;
681
682 /* we intentionally declare these two variables */
683 /* outside of the loop since various compilers emit */
684 /* incorrect warning messages otherwise, talking about */
685 /* `possibly uninitialized variables' */
686 FT_Int p_first = 0; /* make compiler happy */
687 FT_Int p_last = 0;
688
689 FT_Bool left2right;
690
691
692 /* compute direction */
693 prev = best_point;
694
695 do
696 {
697 if ( prev > best_contour_first )
698 prev--;
699 else
700 prev = best_contour_last;
701
702 if ( points[prev].x != best_x )
703 break;
704
705 } while ( prev != best_point );
706
707 /* skip glyph for the degenerate case */
708 if ( prev == best_point )
709 continue;
710
711 left2right = FT_BOOL( points[prev].x < points[best_point].x );
712
713 first = best_segment_last;
714 last = first;
715 hit = 0;
716
717 do
718 {
719 FT_Bool l2r;
720 FT_Pos d;
721
722
723 if ( !hit )
724 {
725 /* no hit; adjust first point */
726 first = last;
727
728 /* also adjust first and last on point */
729 if ( FT_CURVE_TAG( outline.tags[first] ) ==
730 FT_CURVE_TAG_ON )
731 {
732 p_first = first;
733 p_last = first;
734 }
735 else
736 {
737 p_first = -1;
738 p_last = -1;
739 }
740
741 hit = 1;
742 }
743
744 if ( last < best_contour_last )
745 last++;
746 else
747 last = best_contour_first;
748
749 if ( FT_ABS( best_y - points[first].y ) > height_threshold )
750 {
751 /* vertical distance too large */
752 hit = 0;
753 continue;
754 }
755
756 /* same test as above */
757 dist = FT_ABS( points[last].y - points[first].y );
758 if ( dist > 5 )
759 if ( FT_ABS( points[last].x - points[first].x ) <=
760 20 * dist )
761 {
762 hit = 0;
763 continue;
764 }
765
766 if ( FT_CURVE_TAG( outline.tags[last] ) == FT_CURVE_TAG_ON )
767 {
768 p_last = last;
769 if ( p_first < 0 )
770 p_first = last;
771 }
772
773 l2r = FT_BOOL( points[first].x < points[last].x );
774 d = FT_ABS( points[last].x - points[first].x );
775
776 if ( l2r == left2right &&
777 d >= length_threshold )
778 {
779 /* all constraints are met; update segment after */
780 /* finding its end */
781 do
782 {
783 if ( last < best_contour_last )
784 last++;
785 else
786 last = best_contour_first;
787
788 d = FT_ABS( points[last].y - points[first].y );
789 if ( d > 5 )
790 if ( FT_ABS( points[next].x - points[first].x ) <=
791 20 * dist )
792 {
793 if ( last > best_contour_first )
794 last--;
795 else
796 last = best_contour_last;
797 break;
798 }
799
800 p_last = last;
801
802 if ( FT_CURVE_TAG( outline.tags[last] ) ==
803 FT_CURVE_TAG_ON )
804 {
805 p_last = last;
806 if ( p_first < 0 )
807 p_first = last;
808 }
809
810 } while ( last != best_segment_first );
811
812 best_y = points[first].y;
813
814 best_segment_first = first;
815 best_segment_last = last;
816
817 best_on_point_first = p_first;
818 best_on_point_last = p_last;
819
820 break;
821 }
822
823 } while ( last != best_segment_first );
824 }
825 }
826
827 /* for computing blue zones, we add the y offset as returned */
828 /* by the currently used OpenType feature -- for example, */
829 /* superscript glyphs might be identical to subscript glyphs */
830 /* with a vertical shift */
831 best_y += y_offset;
832
833 #ifdef FT_DEBUG_LEVEL_TRACE
834 if ( num_idx == 1 )
835 FT_TRACE5(( " U+%04lX: best_y = %5ld", ch, best_y ));
836 else
837 FT_TRACE5(( " component %d of cluster starting with U+%04lX:"
838 " best_y = %5ld", i, ch, best_y ));
839 #endif
840
841 /* now set the `round' flag depending on the segment's kind: */
842 /* */
843 /* - if the horizontal distance between the first and last */
844 /* `on' point is larger than a heuristic threshold */
845 /* we have a flat segment */
846 /* - if either the first or the last point of the segment is */
847 /* an `off' point, the segment is round, otherwise it is */
848 /* flat */
849 if ( best_on_point_first >= 0 &&
850 best_on_point_last >= 0 &&
851 ( FT_ABS( points[best_on_point_last].x -
852 points[best_on_point_first].x ) ) >
853 flat_threshold )
854 round = 0;
855 else
856 round = FT_BOOL(
857 FT_CURVE_TAG( outline.tags[best_segment_first] ) !=
858 FT_CURVE_TAG_ON ||
859 FT_CURVE_TAG( outline.tags[best_segment_last] ) !=
860 FT_CURVE_TAG_ON );
861
862 if ( round && AF_LATIN_IS_NEUTRAL_BLUE( bs ) )
863 {
864 /* only use flat segments for a neutral blue zone */
865 FT_TRACE5(( " (round, skipped)\n" ));
866 continue;
867 }
868
869 FT_TRACE5(( " (%s)\n", round ? "round" : "flat" ));
870 }
871
872 if ( AF_LATIN_IS_TOP_BLUE( bs ) )
873 {
874 if ( best_y > best_y_extremum )
875 {
876 best_y_extremum = best_y;
877 best_round = round;
878 }
879 }
880 else
881 {
882 if ( best_y < best_y_extremum )
883 {
884 best_y_extremum = best_y;
885 best_round = round;
886 }
887 }
888
889 } /* end for loop */
890
891 if ( !( best_y_extremum == FT_INT_MIN ||
892 best_y_extremum == FT_INT_MAX ) )
893 {
894 if ( best_round )
895 rounds[num_rounds++] = best_y_extremum;
896 else
897 flats[num_flats++] = best_y_extremum;
898 }
899
900 } /* end while loop */
901
902 if ( num_flats == 0 && num_rounds == 0 )
903 {
904 /*
905 * we couldn't find a single glyph to compute this blue zone,
906 * we will simply ignore it then
907 */
908 FT_TRACE5(( " empty\n" ));
909 continue;
910 }
911
912 /* we have computed the contents of the `rounds' and `flats' tables, */
913 /* now determine the reference and overshoot position of the blue -- */
914 /* we simply take the median value after a simple sort */
915 af_sort_pos( num_rounds, rounds );
916 af_sort_pos( num_flats, flats );
917
918 blue = &axis->blues[axis->blue_count];
919 blue_ref = &blue->ref.org;
920 blue_shoot = &blue->shoot.org;
921
922 axis->blue_count++;
923
924 if ( num_flats == 0 )
925 {
926 *blue_ref =
927 *blue_shoot = rounds[num_rounds / 2];
928 }
929 else if ( num_rounds == 0 )
930 {
931 *blue_ref =
932 *blue_shoot = flats[num_flats / 2];
933 }
934 else
935 {
936 *blue_ref = flats [num_flats / 2];
937 *blue_shoot = rounds[num_rounds / 2];
938 }
939
940 /* there are sometimes problems: if the overshoot position of top */
941 /* zones is under its reference position, or the opposite for bottom */
942 /* zones. We must thus check everything there and correct the errors */
943 if ( *blue_shoot != *blue_ref )
944 {
945 FT_Pos ref = *blue_ref;
946 FT_Pos shoot = *blue_shoot;
947 FT_Bool over_ref = FT_BOOL( shoot > ref );
948
949
950 if ( ( AF_LATIN_IS_TOP_BLUE( bs ) ||
951 AF_LATIN_IS_SUB_TOP_BLUE( bs) ) ^ over_ref )
952 {
953 *blue_ref =
954 *blue_shoot = ( shoot + ref ) / 2;
955
956 FT_TRACE5(( " [overshoot smaller than reference,"
957 " taking mean value]\n" ));
958 }
959 }
960
961 blue->ascender = ascender;
962 blue->descender = descender;
963
964 blue->flags = 0;
965 if ( AF_LATIN_IS_TOP_BLUE( bs ) )
966 blue->flags |= AF_LATIN_BLUE_TOP;
967 if ( AF_LATIN_IS_SUB_TOP_BLUE( bs ) )
968 blue->flags |= AF_LATIN_BLUE_SUB_TOP;
969 if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) )
970 blue->flags |= AF_LATIN_BLUE_NEUTRAL;
971
972 /*
973 * The following flag is used later to adjust the y and x scales
974 * in order to optimize the pixel grid alignment of the top of small
975 * letters.
976 */
977 if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) )
978 blue->flags |= AF_LATIN_BLUE_ADJUSTMENT;
979
980 FT_TRACE5(( " -> reference = %ld\n"
981 " overshoot = %ld\n",
982 *blue_ref, *blue_shoot ));
983
984 } /* end for loop */
985
986 af_shaper_buf_destroy( face, shaper_buf );
987
988 if ( axis->blue_count )
989 {
990 /* we finally check whether blue zones are ordered; */
991 /* `ref' and `shoot' values of two blue zones must not overlap */
992
993 FT_UInt i;
994 AF_LatinBlue blue_sorted[AF_BLUE_STRINGSET_MAX_LEN + 2];
995
996
997 for ( i = 0; i < axis->blue_count; i++ )
998 blue_sorted[i] = &axis->blues[i];
999
1000 /* sort bottoms of blue zones... */
1001 af_latin_sort_blue( axis->blue_count, blue_sorted );
1002
1003 /* ...and adjust top values if necessary */
1004 for ( i = 0; i < axis->blue_count - 1; i++ )
1005 {
1006 FT_Pos* a;
1007 FT_Pos* b;
1008
1009 #ifdef FT_DEBUG_LEVEL_TRACE
1010 FT_Bool a_is_top = 0;
1011 #endif
1012
1013
1014 if ( blue_sorted[i]->flags & ( AF_LATIN_BLUE_TOP |
1015 AF_LATIN_BLUE_SUB_TOP ) )
1016 {
1017 a = &blue_sorted[i]->shoot.org;
1018 #ifdef FT_DEBUG_LEVEL_TRACE
1019 a_is_top = 1;
1020 #endif
1021 }
1022 else
1023 a = &blue_sorted[i]->ref.org;
1024
1025 if ( blue_sorted[i + 1]->flags & ( AF_LATIN_BLUE_TOP |
1026 AF_LATIN_BLUE_SUB_TOP ) )
1027 b = &blue_sorted[i + 1]->shoot.org;
1028 else
1029 b = &blue_sorted[i + 1]->ref.org;
1030
1031 if ( *a > *b )
1032 {
1033 *a = *b;
1034 FT_TRACE5(( "blue zone overlap:"
1035 " adjusting %s %d to %ld\n",
1036 a_is_top ? "overshoot" : "reference",
1037 blue_sorted[i] - axis->blues,
1038 *a ));
1039 }
1040 }
1041
1042 FT_TRACE5(( "\n" ));
1043
1044 return 0;
1045 }
1046 else
1047 {
1048 /* disable hinting for the current style if there are no blue zones */
1049
1050 AF_FaceGlobals globals = metrics->root.globals;
1051 FT_UShort* gstyles = globals->glyph_styles;
1052
1053 FT_Long i;
1054
1055
1056 FT_TRACE5(( "no blue zones found:"
1057 " hinting disabled for this style\n" ));
1058
1059 for ( i = 0; i < globals->glyph_count; i++ )
1060 {
1061 if ( ( gstyles[i] & AF_STYLE_MASK ) == sc->style )
1062 gstyles[i] = AF_STYLE_NONE_DFLT;
1063 }
1064
1065 FT_TRACE5(( "\n" ));
1066
1067 return 1;
1068 }
1069 }
1070
1071
1072 /* Check whether all ASCII digits have the same advance width. */
1073
1074 FT_LOCAL_DEF( void )
1075 af_latin_metrics_check_digits( AF_LatinMetrics metrics,
1076 FT_Face face )
1077 {
1078 FT_Bool started = 0, same_width = 1;
1079 FT_Fixed advance = 0, old_advance = 0;
1080
1081 /* If HarfBuzz is not available, we need a pointer to a single */
1082 /* unsigned long value. */
1083 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
1084 void* shaper_buf;
1085 #else
1086 FT_ULong shaper_buf_;
1087 void* shaper_buf = &shaper_buf_;
1088 #endif
1089
1090 /* in all supported charmaps, digits have character codes 0x30-0x39 */
1091 const char digits[] = "0 1 2 3 4 5 6 7 8 9";
1092 const char* p;
1093
1094
1095 p = digits;
1096
1097 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
1098 shaper_buf = af_shaper_buf_create( face );
1099 #endif
1100
1101 while ( *p )
1102 {
1103 FT_ULong glyph_index;
1104 unsigned int num_idx;
1105
1106
1107 /* reject input that maps to more than a single glyph */
1108 p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx );
1109 if ( num_idx > 1 )
1110 continue;
1111
1112 glyph_index = af_shaper_get_elem( &metrics->root,
1113 shaper_buf,
1114 0,
1115 &advance,
1116 NULL );
1117 if ( !glyph_index )
1118 continue;
1119
1120 if ( started )
1121 {
1122 if ( advance != old_advance )
1123 {
1124 same_width = 0;
1125 break;
1126 }
1127 }
1128 else
1129 {
1130 old_advance = advance;
1131 started = 1;
1132 }
1133 }
1134
1135 af_shaper_buf_destroy( face, shaper_buf );
1136
1137 metrics->root.digits_have_same_width = same_width;
1138 }
1139
1140
1141 /* Initialize global metrics. */
1142
1143 FT_LOCAL_DEF( FT_Error )
1144 af_latin_metrics_init( AF_LatinMetrics metrics,
1145 FT_Face face )
1146 {
1147 FT_Error error = FT_Err_Ok;
1148
1149 FT_CharMap oldmap = face->charmap;
1150
1151
1152 metrics->units_per_em = face->units_per_EM;
1153
1154 if ( !FT_Select_Charmap( face, FT_ENCODING_UNICODE ) )
1155 {
1156 af_latin_metrics_init_widths( metrics, face );
1157 if ( af_latin_metrics_init_blues( metrics, face ) )
1158 {
1159 /* use internal error code to indicate missing blue zones */
1160 error = -1;
1161 goto Exit;
1162 }
1163 af_latin_metrics_check_digits( metrics, face );
1164 }
1165
1166 Exit:
1167 FT_Set_Charmap( face, oldmap );
1168 return error;
1169 }
1170
1171
1172 /* Adjust scaling value, then scale and shift widths */
1173 /* and blue zones (if applicable) for given dimension. */
1174
1175 static void
1176 af_latin_metrics_scale_dim( AF_LatinMetrics metrics,
1177 AF_Scaler scaler,
1178 AF_Dimension dim )
1179 {
1180 FT_Fixed scale;
1181 FT_Pos delta;
1182 AF_LatinAxis axis;
1183 FT_UInt nn;
1184
1185
1186 if ( dim == AF_DIMENSION_HORZ )
1187 {
1188 scale = scaler->x_scale;
1189 delta = scaler->x_delta;
1190 }
1191 else
1192 {
1193 scale = scaler->y_scale;
1194 delta = scaler->y_delta;
1195 }
1196
1197 axis = &metrics->axis[dim];
1198
1199 if ( axis->org_scale == scale && axis->org_delta == delta )
1200 return;
1201
1202 axis->org_scale = scale;
1203 axis->org_delta = delta;
1204
1205 /*
1206 * correct X and Y scale to optimize the alignment of the top of small
1207 * letters to the pixel grid
1208 */
1209 {
1210 AF_LatinAxis Axis = &metrics->axis[AF_DIMENSION_VERT];
1211 AF_LatinBlue blue = NULL;
1212
1213
1214 for ( nn = 0; nn < Axis->blue_count; nn++ )
1215 {
1216 if ( Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT )
1217 {
1218 blue = &Axis->blues[nn];
1219 break;
1220 }
1221 }
1222
1223 if ( blue )
1224 {
1225 FT_Pos scaled;
1226 FT_Pos threshold;
1227 FT_Pos fitted;
1228 FT_UInt limit;
1229 FT_UInt ppem;
1230
1231
1232 scaled = FT_MulFix( blue->shoot.org, scale );
1233 ppem = metrics->root.scaler.face->size->metrics.x_ppem;
1234 limit = metrics->root.globals->increase_x_height;
1235 threshold = 40;
1236
1237 /* if the `increase-x-height' property is active, */
1238 /* we round up much more often */
1239 if ( limit &&
1240 ppem <= limit &&
1241 ppem >= AF_PROP_INCREASE_X_HEIGHT_MIN )
1242 threshold = 52;
1243
1244 fitted = ( scaled + threshold ) & ~63;
1245
1246 if ( scaled != fitted )
1247 {
1248 #if 0
1249 if ( dim == AF_DIMENSION_HORZ )
1250 {
1251 if ( fitted < scaled )
1252 scale -= scale / 50; /* scale *= 0.98 */
1253 }
1254 else
1255 #endif
1256 if ( dim == AF_DIMENSION_VERT )
1257 {
1258 FT_Pos max_height;
1259 FT_Pos dist;
1260 FT_Fixed new_scale;
1261
1262
1263 new_scale = FT_MulDiv( scale, fitted, scaled );
1264
1265 /* the scaling should not change the result by more than two pixels */
1266 max_height = metrics->units_per_em;
1267
1268 for ( nn = 0; nn < Axis->blue_count; nn++ )
1269 {
1270 max_height = FT_MAX( max_height, Axis->blues[nn].ascender );
1271 max_height = FT_MAX( max_height, -Axis->blues[nn].descender );
1272 }
1273
1274 dist = FT_ABS( FT_MulFix( max_height, new_scale - scale ) );
1275 dist &= ~127;
1276
1277 if ( dist == 0 )
1278 {
1279 FT_TRACE5((
1280 "af_latin_metrics_scale_dim:"
1281 " x height alignment (style `%s'):\n"
1282 " "
1283 " vertical scaling changed from %.5f to %.5f (by %d%%)\n"
1284 "\n",
1285 af_style_names[metrics->root.style_class->style],
1286 scale / 65536.0,
1287 new_scale / 65536.0,
1288 ( fitted - scaled ) * 100 / scaled ));
1289
1290 scale = new_scale;
1291 }
1292 #ifdef FT_DEBUG_LEVEL_TRACE
1293 else
1294 {
1295 FT_TRACE5((
1296 "af_latin_metrics_scale_dim:"
1297 " x height alignment (style `%s'):\n"
1298 " "
1299 " excessive vertical scaling abandoned\n"
1300 "\n",
1301 af_style_names[metrics->root.style_class->style] ));
1302 }
1303 #endif
1304 }
1305 }
1306 }
1307 }
1308
1309 axis->scale = scale;
1310 axis->delta = delta;
1311
1312 if ( dim == AF_DIMENSION_HORZ )
1313 {
1314 metrics->root.scaler.x_scale = scale;
1315 metrics->root.scaler.x_delta = delta;
1316 }
1317 else
1318 {
1319 metrics->root.scaler.y_scale = scale;
1320 metrics->root.scaler.y_delta = delta;
1321 }
1322
1323 FT_TRACE5(( "%s widths (style `%s')\n",
1324 dim == AF_DIMENSION_HORZ ? "horizontal" : "vertical",
1325 af_style_names[metrics->root.style_class->style] ));
1326
1327 /* scale the widths */
1328 for ( nn = 0; nn < axis->width_count; nn++ )
1329 {
1330 AF_Width width = axis->widths + nn;
1331
1332
1333 width->cur = FT_MulFix( width->org, scale );
1334 width->fit = width->cur;
1335
1336 FT_TRACE5(( " %d scaled to %.2f\n",
1337 width->org,
1338 width->cur / 64.0 ));
1339 }
1340
1341 FT_TRACE5(( "\n" ));
1342
1343 /* an extra-light axis corresponds to a standard width that is */
1344 /* smaller than 5/8 pixels */
1345 axis->extra_light =
1346 FT_BOOL( FT_MulFix( axis->standard_width, scale ) < 32 + 8 );
1347
1348 #ifdef FT_DEBUG_LEVEL_TRACE
1349 if ( axis->extra_light )
1350 FT_TRACE5(( "`%s' style is extra light (at current resolution)\n"
1351 "\n",
1352 af_style_names[metrics->root.style_class->style] ));
1353 #endif
1354
1355 if ( dim == AF_DIMENSION_VERT )
1356 {
1357 #ifdef FT_DEBUG_LEVEL_TRACE
1358 if ( axis->blue_count )
1359 FT_TRACE5(( "blue zones (style `%s')\n",
1360 af_style_names[metrics->root.style_class->style] ));
1361 #endif
1362
1363 /* scale the blue zones */
1364 for ( nn = 0; nn < axis->blue_count; nn++ )
1365 {
1366 AF_LatinBlue blue = &axis->blues[nn];
1367 FT_Pos dist;
1368
1369
1370 blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta;
1371 blue->ref.fit = blue->ref.cur;
1372 blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta;
1373 blue->shoot.fit = blue->shoot.cur;
1374 blue->flags &= ~AF_LATIN_BLUE_ACTIVE;
1375
1376 /* a blue zone is only active if it is less than 3/4 pixels tall */
1377 dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale );
1378 if ( dist <= 48 && dist >= -48 )
1379 {
1380 #if 0
1381 FT_Pos delta1;
1382 #endif
1383 FT_Pos delta2;
1384
1385
1386 /* use discrete values for blue zone widths */
1387
1388 #if 0
1389
1390 /* generic, original code */
1391 delta1 = blue->shoot.org - blue->ref.org;
1392 delta2 = delta1;
1393 if ( delta1 < 0 )
1394 delta2 = -delta2;
1395
1396 delta2 = FT_MulFix( delta2, scale );
1397
1398 if ( delta2 < 32 )
1399 delta2 = 0;
1400 else if ( delta2 < 64 )
1401 delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
1402 else
1403 delta2 = FT_PIX_ROUND( delta2 );
1404
1405 if ( delta1 < 0 )
1406 delta2 = -delta2;
1407
1408 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur );
1409 blue->shoot.fit = blue->ref.fit + delta2;
1410
1411 #else
1412
1413 /* simplified version due to abs(dist) <= 48 */
1414 delta2 = dist;
1415 if ( dist < 0 )
1416 delta2 = -delta2;
1417
1418 if ( delta2 < 32 )
1419 delta2 = 0;
1420 else if ( delta2 < 48 )
1421 delta2 = 32;
1422 else
1423 delta2 = 64;
1424
1425 if ( dist < 0 )
1426 delta2 = -delta2;
1427
1428 blue->ref.fit = FT_PIX_ROUND( blue->ref.cur );
1429 blue->shoot.fit = blue->ref.fit - delta2;
1430
1431 #endif
1432
1433 blue->flags |= AF_LATIN_BLUE_ACTIVE;
1434 }
1435 }
1436
1437 /* use sub-top blue zone only if it doesn't overlap with */
1438 /* another (non-sup-top) blue zone; otherwise, the */
1439 /* effect would be similar to a neutral blue zone, which */
1440 /* is not desired here */
1441 for ( nn = 0; nn < axis->blue_count; nn++ )
1442 {
1443 AF_LatinBlue blue = &axis->blues[nn];
1444 FT_UInt i;
1445
1446
1447 if ( !( blue->flags & AF_LATIN_BLUE_SUB_TOP ) )
1448 continue;
1449 if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) )
1450 continue;
1451
1452 for ( i = 0; i < axis->blue_count; i++ )
1453 {
1454 AF_LatinBlue b = &axis->blues[i];
1455
1456
1457 if ( b->flags & AF_LATIN_BLUE_SUB_TOP )
1458 continue;
1459 if ( !( b->flags & AF_LATIN_BLUE_ACTIVE ) )
1460 continue;
1461
1462 if ( b->ref.fit <= blue->shoot.fit &&
1463 b->shoot.fit >= blue->ref.fit )
1464 {
1465 blue->flags &= ~AF_LATIN_BLUE_ACTIVE;
1466 break;
1467 }
1468 }
1469 }
1470
1471 #ifdef FT_DEBUG_LEVEL_TRACE
1472 for ( nn = 0; nn < axis->blue_count; nn++ )
1473 {
1474 AF_LatinBlue blue = &axis->blues[nn];
1475
1476
1477 FT_TRACE5(( " reference %d: %d scaled to %.2f%s\n"
1478 " overshoot %d: %d scaled to %.2f%s\n",
1479 nn,
1480 blue->ref.org,
1481 blue->ref.fit / 64.0,
1482 ( blue->flags & AF_LATIN_BLUE_ACTIVE ) ? ""
1483 : " (inactive)",
1484 nn,
1485 blue->shoot.org,
1486 blue->shoot.fit / 64.0,
1487 ( blue->flags & AF_LATIN_BLUE_ACTIVE ) ? ""
1488 : " (inactive)" ));
1489 }
1490 #endif
1491 }
1492 }
1493
1494
1495 /* Scale global values in both directions. */
1496
1497 FT_LOCAL_DEF( void )
1498 af_latin_metrics_scale( AF_LatinMetrics metrics,
1499 AF_Scaler scaler )
1500 {
1501 metrics->root.scaler.render_mode = scaler->render_mode;
1502 metrics->root.scaler.face = scaler->face;
1503 metrics->root.scaler.flags = scaler->flags;
1504
1505 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ );
1506 af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT );
1507 }
1508
1509
1510 /* Extract standard_width from writing system/script specific */
1511 /* metrics class. */
1512
1513 FT_LOCAL_DEF( void )
1514 af_latin_get_standard_widths( AF_LatinMetrics metrics,
1515 FT_Pos* stdHW,
1516 FT_Pos* stdVW )
1517 {
1518 if ( stdHW )
1519 *stdHW = metrics->axis[AF_DIMENSION_VERT].standard_width;
1520
1521 if ( stdVW )
1522 *stdVW = metrics->axis[AF_DIMENSION_HORZ].standard_width;
1523 }
1524
1525
1526 /*************************************************************************/
1527 /*************************************************************************/
1528 /***** *****/
1529 /***** L A T I N G L Y P H A N A L Y S I S *****/
1530 /***** *****/
1531 /*************************************************************************/
1532 /*************************************************************************/
1533
1534
1535 /* Walk over all contours and compute its segments. */
1536
1537 FT_LOCAL_DEF( FT_Error )
1538 af_latin_hints_compute_segments( AF_GlyphHints hints,
1539 AF_Dimension dim )
1540 {
1541 AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics;
1542 AF_AxisHints axis = &hints->axis[dim];
1543 FT_Memory memory = hints->memory;
1544 FT_Error error = FT_Err_Ok;
1545 AF_Segment segment = NULL;
1546 AF_SegmentRec seg0;
1547 AF_Point* contour = hints->contours;
1548 AF_Point* contour_limit = contour + hints->num_contours;
1549 AF_Direction major_dir, segment_dir;
1550
1551 FT_Pos flat_threshold = FLAT_THRESHOLD( metrics->units_per_em );
1552
1553
1554 FT_ZERO( &seg0 );
1555 seg0.score = 32000;
1556 seg0.flags = AF_EDGE_NORMAL;
1557
1558 major_dir = (AF_Direction)FT_ABS( axis->major_dir );
1559 segment_dir = major_dir;
1560
1561 axis->num_segments = 0;
1562
1563 /* set up (u,v) in each point */
1564 if ( dim == AF_DIMENSION_HORZ )
1565 {
1566 AF_Point point = hints->points;
1567 AF_Point limit = point + hints->num_points;
1568
1569
1570 for ( ; point < limit; point++ )
1571 {
1572 point->u = point->fx;
1573 point->v = point->fy;
1574 }
1575 }
1576 else
1577 {
1578 AF_Point point = hints->points;
1579 AF_Point limit = point + hints->num_points;
1580
1581
1582 for ( ; point < limit; point++ )
1583 {
1584 point->u = point->fy;
1585 point->v = point->fx;
1586 }
1587 }
1588
1589 /* do each contour separately */
1590 for ( ; contour < contour_limit; contour++ )
1591 {
1592 AF_Point point = contour[0];
1593 AF_Point last = point->prev;
1594 int on_edge = 0;
1595
1596 /* we call values measured along a segment (point->v) */
1597 /* `coordinates', and values orthogonal to it (point->u) */
1598 /* `positions' */
1599 FT_Pos min_pos = 32000;
1600 FT_Pos max_pos = -32000;
1601 FT_Pos min_coord = 32000;
1602 FT_Pos max_coord = -32000;
1603 FT_UShort min_flags = AF_FLAG_NONE;
1604 FT_UShort max_flags = AF_FLAG_NONE;
1605 FT_Pos min_on_coord = 32000;
1606 FT_Pos max_on_coord = -32000;
1607
1608 FT_Bool passed;
1609
1610 AF_Segment prev_segment = NULL;
1611
1612 FT_Pos prev_min_pos = min_pos;
1613 FT_Pos prev_max_pos = max_pos;
1614 FT_Pos prev_min_coord = min_coord;
1615 FT_Pos prev_max_coord = max_coord;
1616 FT_UShort prev_min_flags = min_flags;
1617 FT_UShort prev_max_flags = max_flags;
1618 FT_Pos prev_min_on_coord = min_on_coord;
1619 FT_Pos prev_max_on_coord = max_on_coord;
1620
1621
1622 if ( FT_ABS( last->out_dir ) == major_dir &&
1623 FT_ABS( point->out_dir ) == major_dir )
1624 {
1625 /* we are already on an edge, try to locate its start */
1626 last = point;
1627
1628 for (;;)
1629 {
1630 point = point->prev;
1631 if ( FT_ABS( point->out_dir ) != major_dir )
1632 {
1633 point = point->next;
1634 break;
1635 }
1636 if ( point == last )
1637 break;
1638 }
1639 }
1640
1641 last = point;
1642 passed = 0;
1643
1644 for (;;)
1645 {
1646 FT_Pos u, v;
1647
1648
1649 if ( on_edge )
1650 {
1651 /* get minimum and maximum position */
1652 u = point->u;
1653 if ( u < min_pos )
1654 min_pos = u;
1655 if ( u > max_pos )
1656 max_pos = u;
1657
1658 /* get minimum and maximum coordinate together with flags */
1659 v = point->v;
1660 if ( v < min_coord )
1661 {
1662 min_coord = v;
1663 min_flags = point->flags;
1664 }
1665 if ( v > max_coord )
1666 {
1667 max_coord = v;
1668 max_flags = point->flags;
1669 }
1670
1671 /* get minimum and maximum coordinate of `on' points */
1672 if ( !( point->flags & AF_FLAG_CONTROL ) )
1673 {
1674 v = point->v;
1675 if ( v < min_on_coord )
1676 min_on_coord = v;
1677 if ( v > max_on_coord )
1678 max_on_coord = v;
1679 }
1680
1681 if ( point->out_dir != segment_dir || point == last )
1682 {
1683 /* check whether the new segment's start point is identical to */
1684 /* the previous segment's end point; for example, this might */
1685 /* happen for spikes */
1686
1687 if ( !prev_segment || segment->first != prev_segment->last )
1688 {
1689 /* points are different: we are just leaving an edge, thus */
1690 /* record a new segment */
1691
1692 segment->last = point;
1693 segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 );
1694 segment->delta = (FT_Short)( ( max_pos - min_pos ) >> 1 );
1695
1696 /* a segment is round if either its first or last point */
1697 /* is a control point, and the length of the on points */
1698 /* inbetween doesn't exceed a heuristic limit */
1699 if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL &&
1700 ( max_on_coord - min_on_coord ) < flat_threshold )
1701 segment->flags |= AF_EDGE_ROUND;
1702
1703 segment->min_coord = (FT_Short)min_coord;
1704 segment->max_coord = (FT_Short)max_coord;
1705 segment->height = segment->max_coord - segment->min_coord;
1706
1707 prev_segment = segment;
1708 prev_min_pos = min_pos;
1709 prev_max_pos = max_pos;
1710 prev_min_coord = min_coord;
1711 prev_max_coord = max_coord;
1712 prev_min_flags = min_flags;
1713 prev_max_flags = max_flags;
1714 prev_min_on_coord = min_on_coord;
1715 prev_max_on_coord = max_on_coord;
1716 }
1717 else
1718 {
1719 /* points are the same: we don't create a new segment but */
1720 /* merge the current segment with the previous one */
1721
1722 if ( prev_segment->last->in_dir == point->in_dir )
1723 {
1724 /* we have identical directions (this can happen for */
1725 /* degenerate outlines that move zig-zag along the main */
1726 /* axis without changing the coordinate value of the other */
1727 /* axis, and where the segments have just been merged): */
1728 /* unify segments */
1729
1730 /* update constraints */
1731
1732 if ( prev_min_pos < min_pos )
1733 min_pos = prev_min_pos;
1734 if ( prev_max_pos > max_pos )
1735 max_pos = prev_max_pos;
1736
1737 if ( prev_min_coord < min_coord )
1738 {
1739 min_coord = prev_min_coord;
1740 min_flags = prev_min_flags;
1741 }
1742 if ( prev_max_coord > max_coord )
1743 {
1744 max_coord = prev_max_coord;
1745 max_flags = prev_max_flags;
1746 }
1747
1748 if ( prev_min_on_coord < min_on_coord )
1749 min_on_coord = prev_min_on_coord;
1750 if ( prev_max_on_coord > max_on_coord )
1751 max_on_coord = prev_max_on_coord;
1752
1753 prev_segment->last = point;
1754 prev_segment->pos = (FT_Short)( ( min_pos +
1755 max_pos ) >> 1 );
1756 prev_segment->delta = (FT_Short)( ( max_pos -
1757 min_pos ) >> 1 );
1758
1759 if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL &&
1760 ( max_on_coord - min_on_coord ) < flat_threshold )
1761 prev_segment->flags |= AF_EDGE_ROUND;
1762 else
1763 prev_segment->flags &= ~AF_EDGE_ROUND;
1764
1765 prev_segment->min_coord = (FT_Short)min_coord;
1766 prev_segment->max_coord = (FT_Short)max_coord;
1767 prev_segment->height = prev_segment->max_coord -
1768 prev_segment->min_coord;
1769 }
1770 else
1771 {
1772 /* we have different directions; use the properties of the */
1773 /* longer segment and discard the other one */
1774
1775 if ( FT_ABS( prev_max_coord - prev_min_coord ) >
1776 FT_ABS( max_coord - min_coord ) )
1777 {
1778 /* discard current segment */
1779
1780 if ( min_pos < prev_min_pos )
1781 prev_min_pos = min_pos;
1782 if ( max_pos > prev_max_pos )
1783 prev_max_pos = max_pos;
1784
1785 prev_segment->last = point;
1786 prev_segment->pos = (FT_Short)( ( prev_min_pos +
1787 prev_max_pos ) >> 1 );
1788 prev_segment->delta = (FT_Short)( ( prev_max_pos -
1789 prev_min_pos ) >> 1 );
1790 }
1791 else
1792 {
1793 /* discard previous segment */
1794
1795 if ( prev_min_pos < min_pos )
1796 min_pos = prev_min_pos;
1797 if ( prev_max_pos > max_pos )
1798 max_pos = prev_max_pos;
1799
1800 segment->last = point;
1801 segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 );
1802 segment->delta = (FT_Short)( ( max_pos - min_pos ) >> 1 );
1803
1804 if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL &&
1805 ( max_on_coord - min_on_coord ) < flat_threshold )
1806 segment->flags |= AF_EDGE_ROUND;
1807
1808 segment->min_coord = (FT_Short)min_coord;
1809 segment->max_coord = (FT_Short)max_coord;
1810 segment->height = segment->max_coord -
1811 segment->min_coord;
1812
1813 *prev_segment = *segment;
1814
1815 prev_min_pos = min_pos;
1816 prev_max_pos = max_pos;
1817 prev_min_coord = min_coord;
1818 prev_max_coord = max_coord;
1819 prev_min_flags = min_flags;
1820 prev_max_flags = max_flags;
1821 prev_min_on_coord = min_on_coord;
1822 prev_max_on_coord = max_on_coord;
1823 }
1824 }
1825
1826 axis->num_segments--;
1827 }
1828
1829 on_edge = 0;
1830 segment = NULL;
1831
1832 /* fall through */
1833 }
1834 }
1835
1836 /* now exit if we are at the start/end point */
1837 if ( point == last )
1838 {
1839 if ( passed )
1840 break;
1841 passed = 1;
1842 }
1843
1844 /* if we are not on an edge, check whether the major direction */
1845 /* coincides with the current point's `out' direction, or */
1846 /* whether we have a single-point contour */
1847 if ( !on_edge &&
1848 ( FT_ABS( point->out_dir ) == major_dir ||
1849 point == point->prev ) )
1850 {
1851 /* this is the start of a new segment! */
1852 segment_dir = (AF_Direction)point->out_dir;
1853
1854 error = af_axis_hints_new_segment( axis, memory, &segment );
1855 if ( error )
1856 goto Exit;
1857
1858 /* clear all segment fields */
1859 segment[0] = seg0;
1860
1861 segment->dir = (FT_Char)segment_dir;
1862 segment->first = point;
1863 segment->last = point;
1864
1865 /* `af_axis_hints_new_segment' reallocates memory, */
1866 /* thus we have to refresh the `prev_segment' pointer */
1867 if ( prev_segment )
1868 prev_segment = segment - 1;
1869
1870 min_pos = max_pos = point->u;
1871 min_coord = max_coord = point->v;
1872 min_flags = max_flags = point->flags;
1873
1874 if ( point->flags & AF_FLAG_CONTROL )
1875 {
1876 min_on_coord = 32000;
1877 max_on_coord = -32000;
1878 }
1879 else
1880 min_on_coord = max_on_coord = point->v;
1881
1882 on_edge = 1;
1883
1884 if ( point == point->prev )
1885 {
1886 /* we have a one-point segment: this is a one-point */
1887 /* contour with `in' and `out' direction set to */
1888 /* AF_DIR_NONE */
1889 segment->pos = (FT_Short)min_pos;
1890
1891 if (point->flags & AF_FLAG_CONTROL)
1892 segment->flags |= AF_EDGE_ROUND;
1893
1894 segment->min_coord = (FT_Short)point->v;
1895 segment->max_coord = (FT_Short)point->v;
1896 segment->height = 0;
1897
1898 on_edge = 0;
1899 segment = NULL;
1900 }
1901 }
1902
1903 point = point->next;
1904 }
1905
1906 } /* contours */
1907
1908
1909 /* now slightly increase the height of segments if this makes */
1910 /* sense -- this is used to better detect and ignore serifs */
1911 {
1912 AF_Segment segments = axis->segments;
1913 AF_Segment segments_end = segments + axis->num_segments;
1914
1915
1916 for ( segment = segments; segment < segments_end; segment++ )
1917 {
1918 AF_Point first = segment->first;
1919 AF_Point last = segment->last;
1920 FT_Pos first_v = first->v;
1921 FT_Pos last_v = last->v;
1922
1923
1924 if ( first_v < last_v )
1925 {
1926 AF_Point p;
1927
1928
1929 p = first->prev;
1930 if ( p->v < first_v )
1931 segment->height = (FT_Short)( segment->height +
1932 ( ( first_v - p->v ) >> 1 ) );
1933
1934 p = last->next;
1935 if ( p->v > last_v )
1936 segment->height = (FT_Short)( segment->height +
1937 ( ( p->v - last_v ) >> 1 ) );
1938 }
1939 else
1940 {
1941 AF_Point p;
1942
1943
1944 p = first->prev;
1945 if ( p->v > first_v )
1946 segment->height = (FT_Short)( segment->height +
1947 ( ( p->v - first_v ) >> 1 ) );
1948
1949 p = last->next;
1950 if ( p->v < last_v )
1951 segment->height = (FT_Short)( segment->height +
1952 ( ( last_v - p->v ) >> 1 ) );
1953 }
1954 }
1955 }
1956
1957 Exit:
1958 return error;
1959 }
1960
1961
1962 /* Link segments to form stems and serifs. If `width_count' and */
1963 /* `widths' are non-zero, use them to fine-tune the scoring function. */
1964
1965 FT_LOCAL_DEF( void )
1966 af_latin_hints_link_segments( AF_GlyphHints hints,
1967 FT_UInt width_count,
1968 AF_WidthRec* widths,
1969 AF_Dimension dim )
1970 {
1971 AF_AxisHints axis = &hints->axis[dim];
1972 AF_Segment segments = axis->segments;
1973 AF_Segment segment_limit = segments + axis->num_segments;
1974 FT_Pos len_threshold, len_score, dist_score, max_width;
1975 AF_Segment seg1, seg2;
1976
1977
1978 if ( width_count )
1979 max_width = widths[width_count - 1].org;
1980 else
1981 max_width = 0;
1982
1983 /* a heuristic value to set up a minimum value for overlapping */
1984 len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );
1985 if ( len_threshold == 0 )
1986 len_threshold = 1;
1987
1988 /* a heuristic value to weight lengths */
1989 len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 );
1990
1991 /* a heuristic value to weight distances (no call to */
1992 /* AF_LATIN_CONSTANT needed, since we work on multiples */
1993 /* of the stem width) */
1994 dist_score = 3000;
1995
1996 /* now compare each segment to the others */
1997 for ( seg1 = segments; seg1 < segment_limit; seg1++ )
1998 {
1999 if ( seg1->dir != axis->major_dir )
2000 continue;
2001
2002 /* search for stems having opposite directions, */
2003 /* with seg1 to the `left' of seg2 */
2004 for ( seg2 = segments; seg2 < segment_limit; seg2++ )
2005 {
2006 FT_Pos pos1 = seg1->pos;
2007 FT_Pos pos2 = seg2->pos;
2008
2009
2010 if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 )
2011 {
2012 /* compute distance between the two segments */
2013 FT_Pos min = seg1->min_coord;
2014 FT_Pos max = seg1->max_coord;
2015 FT_Pos len;
2016
2017
2018 if ( min < seg2->min_coord )
2019 min = seg2->min_coord;
2020
2021 if ( max > seg2->max_coord )
2022 max = seg2->max_coord;
2023
2024 /* compute maximum coordinate difference of the two segments */
2025 /* (this is, how much they overlap) */
2026 len = max - min;
2027 if ( len >= len_threshold )
2028 {
2029 /*
2030 * The score is the sum of two demerits indicating the
2031 * `badness' of a fit, measured along the segments' main axis
2032 * and orthogonal to it, respectively.
2033 *
2034 * - The less overlapping along the main axis, the worse it
2035 * is, causing a larger demerit.
2036 *
2037 * - The nearer the orthogonal distance to a stem width, the
2038 * better it is, causing a smaller demerit. For simplicity,
2039 * however, we only increase the demerit for values that
2040 * exceed the largest stem width.
2041 */
2042
2043 FT_Pos dist = pos2 - pos1;
2044
2045 FT_Pos dist_demerit, score;
2046
2047
2048 if ( max_width )
2049 {
2050 /* distance demerits are based on multiples of `max_width'; */
2051 /* we scale by 1024 for getting more precision */
2052 FT_Pos delta = ( dist << 10 ) / max_width - ( 1 << 10 );
2053
2054
2055 if ( delta > 10000 )
2056 dist_demerit = 32000;
2057 else if ( delta > 0 )
2058 dist_demerit = delta * delta / dist_score;
2059 else
2060 dist_demerit = 0;
2061 }
2062 else
2063 dist_demerit = dist; /* default if no widths available */
2064
2065 score = dist_demerit + len_score / len;
2066
2067 /* and we search for the smallest score */
2068 if ( score < seg1->score )
2069 {
2070 seg1->score = score;
2071 seg1->link = seg2;
2072 }
2073
2074 if ( score < seg2->score )
2075 {
2076 seg2->score = score;
2077 seg2->link = seg1;
2078 }
2079 }
2080 }
2081 }
2082 }
2083
2084 /* now compute the `serif' segments, cf. explanations in `afhints.h' */
2085 for ( seg1 = segments; seg1 < segment_limit; seg1++ )
2086 {
2087 seg2 = seg1->link;
2088
2089 if ( seg2 )
2090 {
2091 if ( seg2->link != seg1 )
2092 {
2093 seg1->link = 0;
2094 seg1->serif = seg2->link;
2095 }
2096 }
2097 }
2098 }
2099
2100
2101 /* Link segments to edges, using feature analysis for selection. */
2102
2103 FT_LOCAL_DEF( FT_Error )
2104 af_latin_hints_compute_edges( AF_GlyphHints hints,
2105 AF_Dimension dim )
2106 {
2107 AF_AxisHints axis = &hints->axis[dim];
2108 FT_Error error = FT_Err_Ok;
2109 FT_Memory memory = hints->memory;
2110 AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim];
2111
2112 AF_StyleClass style_class = hints->metrics->style_class;
2113 AF_ScriptClass script_class = af_script_classes[style_class->script];
2114
2115 FT_Bool top_to_bottom_hinting = 0;
2116
2117 AF_Segment segments = axis->segments;
2118 AF_Segment segment_limit = segments + axis->num_segments;
2119 AF_Segment seg;
2120
2121 #if 0
2122 AF_Direction up_dir;
2123 #endif
2124 FT_Fixed scale;
2125 FT_Pos edge_distance_threshold;
2126 FT_Pos segment_length_threshold;
2127 FT_Pos segment_width_threshold;
2128
2129
2130 axis->num_edges = 0;
2131
2132 scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale
2133 : hints->y_scale;
2134
2135 #if 0
2136 up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP
2137 : AF_DIR_RIGHT;
2138 #endif
2139
2140 if ( dim == AF_DIMENSION_VERT )
2141 top_to_bottom_hinting = script_class->top_to_bottom_hinting;
2142
2143 /*
2144 * We ignore all segments that are less than 1 pixel in length
2145 * to avoid many problems with serif fonts. We compute the
2146 * corresponding threshold in font units.
2147 */
2148 if ( dim == AF_DIMENSION_HORZ )
2149 segment_length_threshold = FT_DivFix( 64, hints->y_scale );
2150 else
2151 segment_length_threshold = 0;
2152
2153 /*
2154 * Similarly, we ignore segments that have a width delta
2155 * larger than 0.5px (i.e., a width larger than 1px).
2156 */
2157 segment_width_threshold = FT_DivFix( 32, scale );
2158
2159 /**********************************************************************
2160 *
2161 * We begin by generating a sorted table of edges for the current
2162 * direction. To do so, we simply scan each segment and try to find
2163 * an edge in our table that corresponds to its position.
2164 *
2165 * If no edge is found, we create and insert a new edge in the
2166 * sorted table. Otherwise, we simply add the segment to the edge's
2167 * list which gets processed in the second step to compute the
2168 * edge's properties.
2169 *
2170 * Note that the table of edges is sorted along the segment/edge
2171 * position.
2172 *
2173 */
2174
2175 /* assure that edge distance threshold is at most 0.25px */
2176 edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold,
2177 scale );
2178 if ( edge_distance_threshold > 64 / 4 )
2179 edge_distance_threshold = 64 / 4;
2180
2181 edge_distance_threshold = FT_DivFix( edge_distance_threshold,
2182 scale );
2183
2184 for ( seg = segments; seg < segment_limit; seg++ )
2185 {
2186 AF_Edge found = NULL;
2187 FT_Int ee;
2188
2189
2190 /* ignore too short segments, too wide ones, and, in this loop, */
2191 /* one-point segments without a direction */
2192 if ( seg->height < segment_length_threshold ||
2193 seg->delta > segment_width_threshold ||
2194 seg->dir == AF_DIR_NONE )
2195 continue;
2196
2197 /* A special case for serif edges: If they are smaller than */
2198 /* 1.5 pixels we ignore them. */
2199 if ( seg->serif &&
2200 2 * seg->height < 3 * segment_length_threshold )
2201 continue;
2202
2203 /* look for an edge corresponding to the segment */
2204 for ( ee = 0; ee < axis->num_edges; ee++ )
2205 {
2206 AF_Edge edge = axis->edges + ee;
2207 FT_Pos dist;
2208
2209
2210 dist = seg->pos - edge->fpos;
2211 if ( dist < 0 )
2212 dist = -dist;
2213
2214 if ( dist < edge_distance_threshold && edge->dir == seg->dir )
2215 {
2216 found = edge;
2217 break;
2218 }
2219 }
2220
2221 if ( !found )
2222 {
2223 AF_Edge edge;
2224
2225
2226 /* insert a new edge in the list and */
2227 /* sort according to the position */
2228 error = af_axis_hints_new_edge( axis, seg->pos,
2229 (AF_Direction)seg->dir,
2230 top_to_bottom_hinting,
2231 memory, &edge );
2232 if ( error )
2233 goto Exit;
2234
2235 /* add the segment to the new edge's list */
2236 FT_ZERO( edge );
2237
2238 edge->first = seg;
2239 edge->last = seg;
2240 edge->dir = seg->dir;
2241 edge->fpos = seg->pos;
2242 edge->opos = FT_MulFix( seg->pos, scale );
2243 edge->pos = edge->opos;
2244 seg->edge_next = seg;
2245 }
2246 else
2247 {
2248 /* if an edge was found, simply add the segment to the edge's */
2249 /* list */
2250 seg->edge_next = found->first;
2251 found->last->edge_next = seg;
2252 found->last = seg;
2253 }
2254 }
2255
2256 /* we loop again over all segments to catch one-point segments */
2257 /* without a direction: if possible, link them to existing edges */
2258 for ( seg = segments; seg < segment_limit; seg++ )
2259 {
2260 AF_Edge found = NULL;
2261 FT_Int ee;
2262
2263
2264 if ( seg->dir != AF_DIR_NONE )
2265 continue;
2266
2267 /* look for an edge corresponding to the segment */
2268 for ( ee = 0; ee < axis->num_edges; ee++ )
2269 {
2270 AF_Edge edge = axis->edges + ee;
2271 FT_Pos dist;
2272
2273
2274 dist = seg->pos - edge->fpos;
2275 if ( dist < 0 )
2276 dist = -dist;
2277
2278 if ( dist < edge_distance_threshold )
2279 {
2280 found = edge;
2281 break;
2282 }
2283 }
2284
2285 /* one-point segments without a match are ignored */
2286 if ( found )
2287 {
2288 seg->edge_next = found->first;
2289 found->last->edge_next = seg;
2290 found->last = seg;
2291 }
2292 }
2293
2294
2295 /*******************************************************************
2296 *
2297 * Good, we now compute each edge's properties according to the
2298 * segments found on its position. Basically, these are
2299 *
2300 * - the edge's main direction
2301 * - stem edge, serif edge or both (which defaults to stem then)
2302 * - rounded edge, straight or both (which defaults to straight)
2303 * - link for edge
2304 *
2305 */
2306
2307 /* first of all, set the `edge' field in each segment -- this is */
2308 /* required in order to compute edge links */
2309
2310 /*
2311 * Note that removing this loop and setting the `edge' field of each
2312 * segment directly in the code above slows down execution speed for
2313 * some reasons on platforms like the Sun.
2314 */
2315 {
2316 AF_Edge edges = axis->edges;
2317 AF_Edge edge_limit = edges + axis->num_edges;
2318 AF_Edge edge;
2319
2320
2321 for ( edge = edges; edge < edge_limit; edge++ )
2322 {
2323 seg = edge->first;
2324 if ( seg )
2325 do
2326 {
2327 seg->edge = edge;
2328 seg = seg->edge_next;
2329
2330 } while ( seg != edge->first );
2331 }
2332
2333 /* now compute each edge properties */
2334 for ( edge = edges; edge < edge_limit; edge++ )
2335 {
2336 FT_Int is_round = 0; /* does it contain round segments? */
2337 FT_Int is_straight = 0; /* does it contain straight segments? */
2338 #if 0
2339 FT_Pos ups = 0; /* number of upwards segments */
2340 FT_Pos downs = 0; /* number of downwards segments */
2341 #endif
2342
2343
2344 seg = edge->first;
2345
2346 do
2347 {
2348 FT_Bool is_serif;
2349
2350
2351 /* check for roundness of segment */
2352 if ( seg->flags & AF_EDGE_ROUND )
2353 is_round++;
2354 else
2355 is_straight++;
2356
2357 #if 0
2358 /* check for segment direction */
2359 if ( seg->dir == up_dir )
2360 ups += seg->max_coord - seg->min_coord;
2361 else
2362 downs += seg->max_coord - seg->min_coord;
2363 #endif
2364
2365 /* check for links -- if seg->serif is set, then seg->link must */
2366 /* be ignored */
2367 is_serif = FT_BOOL( seg->serif &&
2368 seg->serif->edge &&
2369 seg->serif->edge != edge );
2370
2371 if ( ( seg->link && seg->link->edge ) || is_serif )
2372 {
2373 AF_Edge edge2;
2374 AF_Segment seg2;
2375
2376
2377 edge2 = edge->link;
2378 seg2 = seg->link;
2379
2380 if ( is_serif )
2381 {
2382 seg2 = seg->serif;
2383 edge2 = edge->serif;
2384 }
2385
2386 if ( edge2 )
2387 {
2388 FT_Pos edge_delta;
2389 FT_Pos seg_delta;
2390
2391
2392 edge_delta = edge->fpos - edge2->fpos;
2393 if ( edge_delta < 0 )
2394 edge_delta = -edge_delta;
2395
2396 seg_delta = seg->pos - seg2->pos;
2397 if ( seg_delta < 0 )
2398 seg_delta = -seg_delta;
2399
2400 if ( seg_delta < edge_delta )
2401 edge2 = seg2->edge;
2402 }
2403 else
2404 edge2 = seg2->edge;
2405
2406 if ( is_serif )
2407 {
2408 edge->serif = edge2;
2409 edge2->flags |= AF_EDGE_SERIF;
2410 }
2411 else
2412 edge->link = edge2;
2413 }
2414
2415 seg = seg->edge_next;
2416
2417 } while ( seg != edge->first );
2418
2419 /* set the round/straight flags */
2420 edge->flags = AF_EDGE_NORMAL;
2421
2422 if ( is_round > 0 && is_round >= is_straight )
2423 edge->flags |= AF_EDGE_ROUND;
2424
2425 #if 0
2426 /* set the edge's main direction */
2427 edge->dir = AF_DIR_NONE;
2428
2429 if ( ups > downs )
2430 edge->dir = (FT_Char)up_dir;
2431
2432 else if ( ups < downs )
2433 edge->dir = (FT_Char)-up_dir;
2434
2435 else if ( ups == downs )
2436 edge->dir = 0; /* both up and down! */
2437 #endif
2438
2439 /* get rid of serifs if link is set */
2440 /* XXX: This gets rid of many unpleasant artefacts! */
2441 /* Example: the `c' in cour.pfa at size 13 */
2442
2443 if ( edge->serif && edge->link )
2444 edge->serif = NULL;
2445 }
2446 }
2447
2448 Exit:
2449 return error;
2450 }
2451
2452
2453 /* Detect segments and edges for given dimension. */
2454
2455 FT_LOCAL_DEF( FT_Error )
2456 af_latin_hints_detect_features( AF_GlyphHints hints,
2457 FT_UInt width_count,
2458 AF_WidthRec* widths,
2459 AF_Dimension dim )
2460 {
2461 FT_Error error;
2462
2463
2464 error = af_latin_hints_compute_segments( hints, dim );
2465 if ( !error )
2466 {
2467 af_latin_hints_link_segments( hints, width_count, widths, dim );
2468
2469 error = af_latin_hints_compute_edges( hints, dim );
2470 }
2471
2472 return error;
2473 }
2474
2475
2476 /* Compute all edges which lie within blue zones. */
2477
2478 static void
2479 af_latin_hints_compute_blue_edges( AF_GlyphHints hints,
2480 AF_LatinMetrics metrics )
2481 {
2482 AF_AxisHints axis = &hints->axis[AF_DIMENSION_VERT];
2483 AF_Edge edge = axis->edges;
2484 AF_Edge edge_limit = edge + axis->num_edges;
2485 AF_LatinAxis latin = &metrics->axis[AF_DIMENSION_VERT];
2486 FT_Fixed scale = latin->scale;
2487
2488
2489 /* compute which blue zones are active, i.e. have their scaled */
2490 /* size < 3/4 pixels */
2491
2492 /* for each horizontal edge search the blue zone which is closest */
2493 for ( ; edge < edge_limit; edge++ )
2494 {
2495 FT_UInt bb;
2496 AF_Width best_blue = NULL;
2497 FT_Bool best_blue_is_neutral = 0;
2498 FT_Pos best_dist; /* initial threshold */
2499
2500
2501 /* compute the initial threshold as a fraction of the EM size */
2502 /* (the value 40 is heuristic) */
2503 best_dist = FT_MulFix( metrics->units_per_em / 40, scale );
2504
2505 /* assure a minimum distance of 0.5px */
2506 if ( best_dist > 64 / 2 )
2507 best_dist = 64 / 2;
2508
2509 for ( bb = 0; bb < latin->blue_count; bb++ )
2510 {
2511 AF_LatinBlue blue = latin->blues + bb;
2512 FT_Bool is_top_blue, is_neutral_blue, is_major_dir;
2513
2514
2515 /* skip inactive blue zones (i.e., those that are too large) */
2516 if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) )
2517 continue;
2518
2519 /* if it is a top zone, check for right edges (against the major */
2520 /* direction); if it is a bottom zone, check for left edges (in */
2521 /* the major direction) -- this assumes the TrueType convention */
2522 /* for the orientation of contours */
2523 is_top_blue =
2524 (FT_Byte)( ( blue->flags & ( AF_LATIN_BLUE_TOP |
2525 AF_LATIN_BLUE_SUB_TOP ) ) != 0 );
2526 is_neutral_blue =
2527 (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_NEUTRAL ) != 0);
2528 is_major_dir =
2529 FT_BOOL( edge->dir == axis->major_dir );
2530
2531 /* neutral blue zones are handled for both directions */
2532 if ( is_top_blue ^ is_major_dir || is_neutral_blue )
2533 {
2534 FT_Pos dist;
2535
2536
2537 /* first of all, compare it to the reference position */
2538 dist = edge->fpos - blue->ref.org;
2539 if ( dist < 0 )
2540 dist = -dist;
2541
2542 dist = FT_MulFix( dist, scale );
2543 if ( dist < best_dist )
2544 {
2545 best_dist = dist;
2546 best_blue = &blue->ref;
2547 best_blue_is_neutral = is_neutral_blue;
2548 }
2549
2550 /* now compare it to the overshoot position and check whether */
2551 /* the edge is rounded, and whether the edge is over the */
2552 /* reference position of a top zone, or under the reference */
2553 /* position of a bottom zone (provided we don't have a */
2554 /* neutral blue zone) */
2555 if ( edge->flags & AF_EDGE_ROUND &&
2556 dist != 0 &&
2557 !is_neutral_blue )
2558 {
2559 FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org );
2560
2561
2562 if ( is_top_blue ^ is_under_ref )
2563 {
2564 dist = edge->fpos - blue->shoot.org;
2565 if ( dist < 0 )
2566 dist = -dist;
2567
2568 dist = FT_MulFix( dist, scale );
2569 if ( dist < best_dist )
2570 {
2571 best_dist = dist;
2572 best_blue = &blue->shoot;
2573 best_blue_is_neutral = is_neutral_blue;
2574 }
2575 }
2576 }
2577 }
2578 }
2579
2580 if ( best_blue )
2581 {
2582 edge->blue_edge = best_blue;
2583 if ( best_blue_is_neutral )
2584 edge->flags |= AF_EDGE_NEUTRAL;
2585 }
2586 }
2587 }
2588
2589
2590 /* Initalize hinting engine. */
2591
2592 static FT_Error
2593 af_latin_hints_init( AF_GlyphHints hints,
2594 AF_LatinMetrics metrics )
2595 {
2596 FT_Render_Mode mode;
2597 FT_UInt32 scaler_flags, other_flags;
2598 FT_Face face = metrics->root.scaler.face;
2599
2600
2601 af_glyph_hints_rescale( hints, (AF_StyleMetrics)metrics );
2602
2603 /*
2604 * correct x_scale and y_scale if needed, since they may have
2605 * been modified by `af_latin_metrics_scale_dim' above
2606 */
2607 hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale;
2608 hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta;
2609 hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale;
2610 hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta;
2611
2612 /* compute flags depending on render mode, etc. */
2613 mode = metrics->root.scaler.render_mode;
2614
2615 #if 0 /* #ifdef AF_CONFIG_OPTION_USE_WARPER */
2616 if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V )
2617 metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL;
2618 #endif
2619
2620 scaler_flags = hints->scaler_flags;
2621 other_flags = 0;
2622
2623 /*
2624 * We snap the width of vertical stems for the monochrome and
2625 * horizontal LCD rendering targets only.
2626 */
2627 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD )
2628 other_flags |= AF_LATIN_HINTS_HORZ_SNAP;
2629
2630 /*
2631 * We snap the width of horizontal stems for the monochrome and
2632 * vertical LCD rendering targets only.
2633 */
2634 if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V )
2635 other_flags |= AF_LATIN_HINTS_VERT_SNAP;
2636
2637 /*
2638 * We adjust stems to full pixels unless in `light' or `lcd' mode.
2639 */
2640 if ( mode != FT_RENDER_MODE_LIGHT && mode != FT_RENDER_MODE_LCD )
2641 other_flags |= AF_LATIN_HINTS_STEM_ADJUST;
2642
2643 if ( mode == FT_RENDER_MODE_MONO )
2644 other_flags |= AF_LATIN_HINTS_MONO;
2645
2646 /*
2647 * In `light' or `lcd' mode we disable horizontal hinting completely.
2648 * We also do it if the face is italic.
2649 *
2650 * However, if warping is enabled (which only works in `light' hinting
2651 * mode), advance widths get adjusted, too.
2652 */
2653 if ( mode == FT_RENDER_MODE_LIGHT || mode == FT_RENDER_MODE_LCD ||
2654 ( face->style_flags & FT_STYLE_FLAG_ITALIC ) != 0 )
2655 scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL;
2656
2657 #ifdef AF_CONFIG_OPTION_USE_WARPER
2658 /* get (global) warper flag */
2659 if ( !metrics->root.globals->module->warping )
2660 scaler_flags |= AF_SCALER_FLAG_NO_WARPER;
2661 #endif
2662
2663 hints->scaler_flags = scaler_flags;
2664 hints->other_flags = other_flags;
2665
2666 return FT_Err_Ok;
2667 }
2668
2669
2670 /*************************************************************************/
2671 /*************************************************************************/
2672 /***** *****/
2673 /***** L A T I N G L Y P H G R I D - F I T T I N G *****/
2674 /***** *****/
2675 /*************************************************************************/
2676 /*************************************************************************/
2677
2678 /* Snap a given width in scaled coordinates to one of the */
2679 /* current standard widths. */
2680
2681 static FT_Pos
2682 af_latin_snap_width( AF_Width widths,
2683 FT_UInt count,
2684 FT_Pos width )
2685 {
2686 FT_UInt n;
2687 FT_Pos best = 64 + 32 + 2;
2688 FT_Pos reference = width;
2689 FT_Pos scaled;
2690
2691
2692 for ( n = 0; n < count; n++ )
2693 {
2694 FT_Pos w;
2695 FT_Pos dist;
2696
2697
2698 w = widths[n].cur;
2699 dist = width - w;
2700 if ( dist < 0 )
2701 dist = -dist;
2702 if ( dist < best )
2703 {
2704 best = dist;
2705 reference = w;
2706 }
2707 }
2708
2709 scaled = FT_PIX_ROUND( reference );
2710
2711 if ( width >= reference )
2712 {
2713 if ( width < scaled + 48 )
2714 width = reference;
2715 }
2716 else
2717 {
2718 if ( width > scaled - 48 )
2719 width = reference;
2720 }
2721
2722 return width;
2723 }
2724
2725
2726 /* Compute the snapped width of a given stem, ignoring very thin ones. */
2727 /* There is a lot of voodoo in this function; changing the hard-coded */
2728 /* parameters influence the whole hinting process. */
2729
2730 static FT_Pos
2731 af_latin_compute_stem_width( AF_GlyphHints hints,
2732 AF_Dimension dim,
2733 FT_Pos width,
2734 FT_Pos base_delta,
2735 FT_UInt base_flags,
2736 FT_UInt stem_flags )
2737 {
2738 AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics;
2739 AF_LatinAxis axis = &metrics->axis[dim];
2740 FT_Pos dist = width;
2741 FT_Int sign = 0;
2742 FT_Int vertical = ( dim == AF_DIMENSION_VERT );
2743
2744
2745 if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) ||
2746 axis->extra_light )
2747 return width;
2748
2749 if ( dist < 0 )
2750 {
2751 dist = -width;
2752 sign = 1;
2753 }
2754
2755 if ( ( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) ||
2756 ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) )
2757 {
2758 /* smooth hinting process: very lightly quantize the stem width */
2759
2760 /* leave the widths of serifs alone */
2761 if ( ( stem_flags & AF_EDGE_SERIF ) &&
2762 vertical &&
2763 ( dist < 3 * 64 ) )
2764 goto Done_Width;
2765
2766 else if ( base_flags & AF_EDGE_ROUND )
2767 {
2768 if ( dist < 80 )
2769 dist = 64;
2770 }
2771 else if ( dist < 56 )
2772 dist = 56;
2773
2774 if ( axis->width_count > 0 )
2775 {
2776 FT_Pos delta;
2777
2778
2779 /* compare to standard width */
2780 delta = dist - axis->widths[0].cur;
2781
2782 if ( delta < 0 )
2783 delta = -delta;
2784
2785 if ( delta < 40 )
2786 {
2787 dist = axis->widths[0].cur;
2788 if ( dist < 48 )
2789 dist = 48;
2790
2791 goto Done_Width;
2792 }
2793
2794 if ( dist < 3 * 64 )
2795 {
2796 delta = dist & 63;
2797 dist &= -64;
2798
2799 if ( delta < 10 )
2800 dist += delta;
2801
2802 else if ( delta < 32 )
2803 dist += 10;
2804
2805 else if ( delta < 54 )
2806 dist += 54;
2807
2808 else
2809 dist += delta;
2810 }
2811 else
2812 {
2813 /* A stem's end position depends on two values: the start */
2814 /* position and the stem length. The former gets usually */
2815 /* rounded to the grid, while the latter gets rounded also if it */
2816 /* exceeds a certain length (see below in this function). This */
2817 /* `double rounding' can lead to a great difference to the */
2818 /* original, unhinted position; this normally doesn't matter for */
2819 /* large PPEM values, but for small sizes it can easily make */
2820 /* outlines collide. For this reason, we adjust the stem length */
2821 /* by a small amount depending on the PPEM value in case the */
2822 /* former and latter rounding both point into the same */
2823 /* direction. */
2824
2825 FT_Pos bdelta = 0;
2826
2827
2828 if ( ( ( width > 0 ) && ( base_delta > 0 ) ) ||
2829 ( ( width < 0 ) && ( base_delta < 0 ) ) )
2830 {
2831 FT_UInt ppem = metrics->root.scaler.face->size->metrics.x_ppem;
2832
2833
2834 if ( ppem < 10 )
2835 bdelta = base_delta;
2836 else if ( ppem < 30 )
2837 bdelta = ( base_delta * (FT_Pos)( 30 - ppem ) ) / 20;
2838
2839 if ( bdelta < 0 )
2840 bdelta = -bdelta;
2841 }
2842
2843 dist = ( dist - bdelta + 32 ) & ~63;
2844 }
2845 }
2846 }
2847 else
2848 {
2849 /* strong hinting process: snap the stem width to integer pixels */
2850
2851 FT_Pos org_dist = dist;
2852
2853
2854 dist = af_latin_snap_width( axis->widths, axis->width_count, dist );
2855
2856 if ( vertical )
2857 {
2858 /* in the case of vertical hinting, always round */
2859 /* the stem heights to integer pixels */
2860
2861 if ( dist >= 64 )
2862 dist = ( dist + 16 ) & ~63;
2863 else
2864 dist = 64;
2865 }
2866 else
2867 {
2868 if ( AF_LATIN_HINTS_DO_MONO( hints ) )
2869 {
2870 /* monochrome horizontal hinting: snap widths to integer pixels */
2871 /* with a different threshold */
2872
2873 if ( dist < 64 )
2874 dist = 64;
2875 else
2876 dist = ( dist + 32 ) & ~63;
2877 }
2878 else
2879 {
2880 /* for horizontal anti-aliased hinting, we adopt a more subtle */
2881 /* approach: we strengthen small stems, round stems whose size */
2882 /* is between 1 and 2 pixels to an integer, otherwise nothing */
2883
2884 if ( dist < 48 )
2885 dist = ( dist + 64 ) >> 1;
2886
2887 else if ( dist < 128 )
2888 {
2889 /* We only round to an integer width if the corresponding */
2890 /* distortion is less than 1/4 pixel. Otherwise this */
2891 /* makes everything worse since the diagonals, which are */
2892 /* not hinted, appear a lot bolder or thinner than the */
2893 /* vertical stems. */
2894
2895 FT_Pos delta;
2896
2897
2898 dist = ( dist + 22 ) & ~63;
2899 delta = dist - org_dist;
2900 if ( delta < 0 )
2901 delta = -delta;
2902
2903 if ( delta >= 16 )
2904 {
2905 dist = org_dist;
2906 if ( dist < 48 )
2907 dist = ( dist + 64 ) >> 1;
2908 }
2909 }
2910 else
2911 /* round otherwise to prevent color fringes in LCD mode */
2912 dist = ( dist + 32 ) & ~63;
2913 }
2914 }
2915 }
2916
2917 Done_Width:
2918 if ( sign )
2919 dist = -dist;
2920
2921 return dist;
2922 }
2923
2924
2925 /* Align one stem edge relative to the previous stem edge. */
2926
2927 static void
2928 af_latin_align_linked_edge( AF_GlyphHints hints,
2929 AF_Dimension dim,
2930 AF_Edge base_edge,
2931 AF_Edge stem_edge )
2932 {
2933 FT_Pos dist, base_delta;
2934 FT_Pos fitted_width;
2935
2936
2937 dist = stem_edge->opos - base_edge->opos;
2938 base_delta = base_edge->pos - base_edge->opos;
2939
2940 fitted_width = af_latin_compute_stem_width( hints, dim,
2941 dist, base_delta,
2942 base_edge->flags,
2943 stem_edge->flags );
2944
2945
2946 stem_edge->pos = base_edge->pos + fitted_width;
2947
2948 FT_TRACE5(( " LINK: edge %d (opos=%.2f) linked to %.2f,"
2949 " dist was %.2f, now %.2f\n",
2950 stem_edge - hints->axis[dim].edges, stem_edge->opos / 64.0,
2951 stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 ));
2952 }
2953
2954
2955 /* Shift the coordinates of the `serif' edge by the same amount */
2956 /* as the corresponding `base' edge has been moved already. */
2957
2958 static void
2959 af_latin_align_serif_edge( AF_GlyphHints hints,
2960 AF_Edge base,
2961 AF_Edge serif )
2962 {
2963 FT_UNUSED( hints );
2964
2965 serif->pos = base->pos + ( serif->opos - base->opos );
2966 }
2967
2968
2969 /*************************************************************************/
2970 /*************************************************************************/
2971 /*************************************************************************/
2972 /**** ****/
2973 /**** E D G E H I N T I N G ****/
2974 /**** ****/
2975 /*************************************************************************/
2976 /*************************************************************************/
2977 /*************************************************************************/
2978
2979
2980 /* The main grid-fitting routine. */
2981
2982 static void
2983 af_latin_hint_edges( AF_GlyphHints hints,
2984 AF_Dimension dim )
2985 {
2986 AF_AxisHints axis = &hints->axis[dim];
2987 AF_Edge edges = axis->edges;
2988 AF_Edge edge_limit = edges + axis->num_edges;
2989 FT_PtrDist n_edges;
2990 AF_Edge edge;
2991 AF_Edge anchor = NULL;
2992 FT_Int has_serifs = 0;
2993
2994 AF_StyleClass style_class = hints->metrics->style_class;
2995 AF_ScriptClass script_class = af_script_classes[style_class->script];
2996
2997 FT_Bool top_to_bottom_hinting = 0;
2998
2999 #ifdef FT_DEBUG_LEVEL_TRACE
3000 FT_UInt num_actions = 0;
3001 #endif
3002
3003
3004 FT_TRACE5(( "latin %s edge hinting (style `%s')\n",
3005 dim == AF_DIMENSION_VERT ? "horizontal" : "vertical",
3006 af_style_names[hints->metrics->style_class->style] ));
3007
3008 if ( dim == AF_DIMENSION_VERT )
3009 top_to_bottom_hinting = script_class->top_to_bottom_hinting;
3010
3011 /* we begin by aligning all stems relative to the blue zone */
3012 /* if needed -- that's only for horizontal edges */
3013
3014 if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) )
3015 {
3016 for ( edge = edges; edge < edge_limit; edge++ )
3017 {
3018 AF_Width blue;
3019 AF_Edge edge1, edge2; /* these edges form the stem to check */
3020
3021
3022 if ( edge->flags & AF_EDGE_DONE )
3023 continue;
3024
3025 edge1 = NULL;
3026 edge2 = edge->link;
3027
3028 /*
3029 * If a stem contains both a neutral and a non-neutral blue zone,
3030 * skip the neutral one. Otherwise, outlines with different
3031 * directions might be incorrectly aligned at the same vertical
3032 * position.
3033 *
3034 * If we have two neutral blue zones, skip one of them.
3035 *
3036 */
3037 if ( edge->blue_edge && edge2 && edge2->blue_edge )
3038 {
3039 FT_Byte neutral = edge->flags & AF_EDGE_NEUTRAL;
3040 FT_Byte neutral2 = edge2->flags & AF_EDGE_NEUTRAL;
3041
3042
3043 if ( neutral2 )
3044 {
3045 edge2->blue_edge = NULL;
3046 edge2->flags &= ~AF_EDGE_NEUTRAL;
3047 }
3048 else if ( neutral )
3049 {
3050 edge->blue_edge = NULL;
3051 edge->flags &= ~AF_EDGE_NEUTRAL;
3052 }
3053 }
3054
3055 blue = edge->blue_edge;
3056 if ( blue )
3057 edge1 = edge;
3058
3059 /* flip edges if the other edge is aligned to a blue zone */
3060 else if ( edge2 && edge2->blue_edge )
3061 {
3062 blue = edge2->blue_edge;
3063 edge1 = edge2;
3064 edge2 = edge;
3065 }
3066
3067 if ( !edge1 )
3068 continue;
3069
3070 #ifdef FT_DEBUG_LEVEL_TRACE
3071 if ( !anchor )
3072 FT_TRACE5(( " BLUE_ANCHOR: edge %d (opos=%.2f) snapped to %.2f,"
3073 " was %.2f (anchor=edge %d)\n",
3074 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0,
3075 edge1->pos / 64.0, edge - edges ));
3076 else
3077 FT_TRACE5(( " BLUE: edge %d (opos=%.2f) snapped to %.2f,"
3078 " was %.2f\n",
3079 edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0,
3080 edge1->pos / 64.0 ));
3081
3082 num_actions++;
3083 #endif
3084
3085 edge1->pos = blue->fit;
3086 edge1->flags |= AF_EDGE_DONE;
3087
3088 if ( edge2 && !edge2->blue_edge )
3089 {
3090 af_latin_align_linked_edge( hints, dim, edge1, edge2 );
3091 edge2->flags |= AF_EDGE_DONE;
3092
3093 #ifdef FT_DEBUG_LEVEL_TRACE
3094 num_actions++;
3095 #endif
3096 }
3097
3098 if ( !anchor )
3099 anchor = edge;
3100 }
3101 }
3102
3103 /* now we align all other stem edges, trying to maintain the */
3104 /* relative order of stems in the glyph */
3105 for ( edge = edges; edge < edge_limit; edge++ )
3106 {
3107 AF_Edge edge2;
3108
3109
3110 if ( edge->flags & AF_EDGE_DONE )
3111 continue;
3112
3113 /* skip all non-stem edges */
3114 edge2 = edge->link;
3115 if ( !edge2 )
3116 {
3117 has_serifs++;
3118 continue;
3119 }
3120
3121 /* now align the stem */
3122
3123 /* this should not happen, but it's better to be safe */
3124 if ( edge2->blue_edge )
3125 {
3126 FT_TRACE5(( " ASSERTION FAILED for edge %d\n", edge2 - edges ));
3127
3128 af_latin_align_linked_edge( hints, dim, edge2, edge );
3129 edge->flags |= AF_EDGE_DONE;
3130
3131 #ifdef FT_DEBUG_LEVEL_TRACE
3132 num_actions++;
3133 #endif
3134 continue;
3135 }
3136
3137 if ( !anchor )
3138 {
3139 /* if we reach this if clause, no stem has been aligned yet */
3140
3141 FT_Pos org_len, org_center, cur_len;
3142 FT_Pos cur_pos1, error1, error2, u_off, d_off;
3143
3144
3145 org_len = edge2->opos - edge->opos;
3146 cur_len = af_latin_compute_stem_width( hints, dim,
3147 org_len, 0,
3148 edge->flags,
3149 edge2->flags );
3150
3151 /* some voodoo to specially round edges for small stem widths; */
3152 /* the idea is to align the center of a stem, then shifting */
3153 /* the stem edges to suitable positions */
3154 if ( cur_len <= 64 )
3155 {
3156 /* width <= 1px */
3157 u_off = 32;
3158 d_off = 32;
3159 }
3160 else
3161 {
3162 /* 1px < width < 1.5px */
3163 u_off = 38;
3164 d_off = 26;
3165 }
3166
3167 if ( cur_len < 96 )
3168 {
3169 org_center = edge->opos + ( org_len >> 1 );
3170 cur_pos1 = FT_PIX_ROUND( org_center );
3171
3172 error1 = org_center - ( cur_pos1 - u_off );
3173 if ( error1 < 0 )
3174 error1 = -error1;
3175
3176 error2 = org_center - ( cur_pos1 + d_off );
3177 if ( error2 < 0 )
3178 error2 = -error2;
3179
3180 if ( error1 < error2 )
3181 cur_pos1 -= u_off;
3182 else
3183 cur_pos1 += d_off;
3184
3185 edge->pos = cur_pos1 - cur_len / 2;
3186 edge2->pos = edge->pos + cur_len;
3187 }
3188 else
3189 edge->pos = FT_PIX_ROUND( edge->opos );
3190
3191 anchor = edge;
3192 edge->flags |= AF_EDGE_DONE;
3193
3194 FT_TRACE5(( " ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f)"
3195 " snapped to %.2f and %.2f\n",
3196 edge - edges, edge->opos / 64.0,
3197 edge2 - edges, edge2->opos / 64.0,
3198 edge->pos / 64.0, edge2->pos / 64.0 ));
3199
3200 af_latin_align_linked_edge( hints, dim, edge, edge2 );
3201
3202 #ifdef FT_DEBUG_LEVEL_TRACE
3203 num_actions += 2;
3204 #endif
3205 }
3206 else
3207 {
3208 FT_Pos org_pos, org_len, org_center, cur_len;
3209 FT_Pos cur_pos1, cur_pos2, delta1, delta2;
3210
3211
3212 org_pos = anchor->pos + ( edge->opos - anchor->opos );
3213 org_len = edge2->opos - edge->opos;
3214 org_center = org_pos + ( org_len >> 1 );
3215
3216 cur_len = af_latin_compute_stem_width( hints, dim,
3217 org_len, 0,
3218 edge->flags,
3219 edge2->flags );
3220
3221 if ( edge2->flags & AF_EDGE_DONE )
3222 {
3223 FT_TRACE5(( " ADJUST: edge %d (pos=%.2f) moved to %.2f\n",
3224 edge - edges, edge->pos / 64.0,
3225 ( edge2->pos - cur_len ) / 64.0 ));
3226
3227 edge->pos = edge2->pos - cur_len;
3228 }
3229
3230 else if ( cur_len < 96 )
3231 {
3232 FT_Pos u_off, d_off;
3233
3234
3235 cur_pos1 = FT_PIX_ROUND( org_center );
3236
3237 if ( cur_len <= 64 )
3238 {
3239 u_off = 32;
3240 d_off = 32;
3241 }
3242 else
3243 {
3244 u_off = 38;
3245 d_off = 26;
3246 }
3247
3248 delta1 = org_center - ( cur_pos1 - u_off );
3249 if ( delta1 < 0 )
3250 delta1 = -delta1;
3251
3252 delta2 = org_center - ( cur_pos1 + d_off );
3253 if ( delta2 < 0 )
3254 delta2 = -delta2;
3255
3256 if ( delta1 < delta2 )
3257 cur_pos1 -= u_off;
3258 else
3259 cur_pos1 += d_off;
3260
3261 edge->pos = cur_pos1 - cur_len / 2;
3262 edge2->pos = cur_pos1 + cur_len / 2;
3263
3264 FT_TRACE5(( " STEM: edge %d (opos=%.2f) linked to %d (opos=%.2f)"
3265 " snapped to %.2f and %.2f\n",
3266 edge - edges, edge->opos / 64.0,
3267 edge2 - edges, edge2->opos / 64.0,
3268 edge->pos / 64.0, edge2->pos / 64.0 ));
3269 }
3270
3271 else
3272 {
3273 org_pos = anchor->pos + ( edge->opos - anchor->opos );
3274 org_len = edge2->opos - edge->opos;
3275 org_center = org_pos + ( org_len >> 1 );
3276
3277 cur_len = af_latin_compute_stem_width( hints, dim,
3278 org_len, 0,
3279 edge->flags,
3280 edge2->flags );
3281
3282 cur_pos1 = FT_PIX_ROUND( org_pos );
3283 delta1 = cur_pos1 + ( cur_len >> 1 ) - org_center;
3284 if ( delta1 < 0 )
3285 delta1 = -delta1;
3286
3287 cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len;
3288 delta2 = cur_pos2 + ( cur_len >> 1 ) - org_center;
3289 if ( delta2 < 0 )
3290 delta2 = -delta2;
3291
3292 edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2;
3293 edge2->pos = edge->pos + cur_len;
3294
3295 FT_TRACE5(( " STEM: edge %d (opos=%.2f) linked to %d (opos=%.2f)"
3296 " snapped to %.2f and %.2f\n",
3297 edge - edges, edge->opos / 64.0,
3298 edge2 - edges, edge2->opos / 64.0,
3299 edge->pos / 64.0, edge2->pos / 64.0 ));
3300 }
3301
3302 #ifdef FT_DEBUG_LEVEL_TRACE
3303 num_actions++;
3304 #endif
3305
3306 edge->flags |= AF_EDGE_DONE;
3307 edge2->flags |= AF_EDGE_DONE;
3308
3309 if ( edge > edges &&
3310 ( top_to_bottom_hinting ? ( edge->pos > edge[-1].pos )
3311 : ( edge->pos < edge[-1].pos ) ) )
3312 {
3313 /* don't move if stem would (almost) disappear otherwise; */
3314 /* the ad-hoc value 16 corresponds to 1/4px */
3315 if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 )
3316 {
3317 #ifdef FT_DEBUG_LEVEL_TRACE
3318 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n",
3319 edge - edges,
3320 edge->pos / 64.0,
3321 edge[-1].pos / 64.0 ));
3322
3323 num_actions++;
3324 #endif
3325
3326 edge->pos = edge[-1].pos;
3327 }
3328 }
3329 }
3330 }
3331
3332 /* make sure that lowercase m's maintain their symmetry */
3333
3334 /* In general, lowercase m's have six vertical edges if they are sans */
3335 /* serif, or twelve if they are with serifs. This implementation is */
3336 /* based on that assumption, and seems to work very well with most */
3337 /* faces. However, if for a certain face this assumption is not */
3338 /* true, the m is just rendered like before. In addition, any stem */
3339 /* correction will only be applied to symmetrical glyphs (even if the */
3340 /* glyph is not an m), so the potential for unwanted distortion is */
3341 /* relatively low. */
3342
3343 /* We don't handle horizontal edges since we can't easily assure that */
3344 /* the third (lowest) stem aligns with the base line; it might end up */
3345 /* one pixel higher or lower. */
3346
3347 n_edges = edge_limit - edges;
3348 if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) )
3349 {
3350 AF_Edge edge1, edge2, edge3;
3351 FT_Pos dist1, dist2, span, delta;
3352
3353
3354 if ( n_edges == 6 )
3355 {
3356 edge1 = edges;
3357 edge2 = edges + 2;
3358 edge3 = edges + 4;
3359 }
3360 else
3361 {
3362 edge1 = edges + 1;
3363 edge2 = edges + 5;
3364 edge3 = edges + 9;
3365 }
3366
3367 dist1 = edge2->opos - edge1->opos;
3368 dist2 = edge3->opos - edge2->opos;
3369
3370 span = dist1 - dist2;
3371 if ( span < 0 )
3372 span = -span;
3373
3374 if ( span < 8 )
3375 {
3376 delta = edge3->pos - ( 2 * edge2->pos - edge1->pos );
3377 edge3->pos -= delta;
3378 if ( edge3->link )
3379 edge3->link->pos -= delta;
3380
3381 /* move the serifs along with the stem */
3382 if ( n_edges == 12 )
3383 {
3384 ( edges + 8 )->pos -= delta;
3385 ( edges + 11 )->pos -= delta;
3386 }
3387
3388 edge3->flags |= AF_EDGE_DONE;
3389 if ( edge3->link )
3390 edge3->link->flags |= AF_EDGE_DONE;
3391 }
3392 }
3393
3394 if ( has_serifs || !anchor )
3395 {
3396 /*
3397 * now hint the remaining edges (serifs and single) in order
3398 * to complete our processing
3399 */
3400 for ( edge = edges; edge < edge_limit; edge++ )
3401 {
3402 FT_Pos delta;
3403
3404
3405 if ( edge->flags & AF_EDGE_DONE )
3406 continue;
3407
3408 delta = 1000;
3409
3410 if ( edge->serif )
3411 {
3412 delta = edge->serif->opos - edge->opos;
3413 if ( delta < 0 )
3414 delta = -delta;
3415 }
3416
3417 if ( delta < 64 + 16 )
3418 {
3419 af_latin_align_serif_edge( hints, edge->serif, edge );
3420 FT_TRACE5(( " SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f)"
3421 " aligned to %.2f\n",
3422 edge - edges, edge->opos / 64.0,
3423 edge->serif - edges, edge->serif->opos / 64.0,
3424 edge->pos / 64.0 ));
3425 }
3426 else if ( !anchor )
3427 {
3428 edge->pos = FT_PIX_ROUND( edge->opos );
3429 anchor = edge;
3430 FT_TRACE5(( " SERIF_ANCHOR: edge %d (opos=%.2f)"
3431 " snapped to %.2f\n",
3432 edge-edges, edge->opos / 64.0, edge->pos / 64.0 ));
3433 }
3434 else
3435 {
3436 AF_Edge before, after;
3437
3438
3439 for ( before = edge - 1; before >= edges; before-- )
3440 if ( before->flags & AF_EDGE_DONE )
3441 break;
3442
3443 for ( after = edge + 1; after < edge_limit; after++ )
3444 if ( after->flags & AF_EDGE_DONE )
3445 break;
3446
3447 if ( before >= edges && before < edge &&
3448 after < edge_limit && after > edge )
3449 {
3450 if ( after->opos == before->opos )
3451 edge->pos = before->pos;
3452 else
3453 edge->pos = before->pos +
3454 FT_MulDiv( edge->opos - before->opos,
3455 after->pos - before->pos,
3456 after->opos - before->opos );
3457
3458 FT_TRACE5(( " SERIF_LINK1: edge %d (opos=%.2f) snapped to %.2f"
3459 " from %d (opos=%.2f)\n",
3460 edge - edges, edge->opos / 64.0,
3461 edge->pos / 64.0,
3462 before - edges, before->opos / 64.0 ));
3463 }
3464 else
3465 {
3466 edge->pos = anchor->pos +
3467 ( ( edge->opos - anchor->opos + 16 ) & ~31 );
3468 FT_TRACE5(( " SERIF_LINK2: edge %d (opos=%.2f)"
3469 " snapped to %.2f\n",
3470 edge - edges, edge->opos / 64.0, edge->pos / 64.0 ));
3471 }
3472 }
3473
3474 #ifdef FT_DEBUG_LEVEL_TRACE
3475 num_actions++;
3476 #endif
3477 edge->flags |= AF_EDGE_DONE;
3478
3479 if ( edge > edges &&
3480 ( top_to_bottom_hinting ? ( edge->pos > edge[-1].pos )
3481 : ( edge->pos < edge[-1].pos ) ) )
3482 {
3483 /* don't move if stem would (almost) disappear otherwise; */
3484 /* the ad-hoc value 16 corresponds to 1/4px */
3485 if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 )
3486 {
3487 #ifdef FT_DEBUG_LEVEL_TRACE
3488 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n",
3489 edge - edges,
3490 edge->pos / 64.0,
3491 edge[-1].pos / 64.0 ));
3492
3493 num_actions++;
3494 #endif
3495 edge->pos = edge[-1].pos;
3496 }
3497 }
3498
3499 if ( edge + 1 < edge_limit &&
3500 edge[1].flags & AF_EDGE_DONE &&
3501 ( top_to_bottom_hinting ? ( edge->pos < edge[1].pos )
3502 : ( edge->pos > edge[1].pos ) ) )
3503 {
3504 /* don't move if stem would (almost) disappear otherwise; */
3505 /* the ad-hoc value 16 corresponds to 1/4px */
3506 if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 )
3507 {
3508 #ifdef FT_DEBUG_LEVEL_TRACE
3509 FT_TRACE5(( " BOUND: edge %d (pos=%.2f) moved to %.2f\n",
3510 edge - edges,
3511 edge->pos / 64.0,
3512 edge[1].pos / 64.0 ));
3513
3514 num_actions++;
3515 #endif
3516
3517 edge->pos = edge[1].pos;
3518 }
3519 }
3520 }
3521 }
3522
3523 #ifdef FT_DEBUG_LEVEL_TRACE
3524 if ( !num_actions )
3525 FT_TRACE5(( " (none)\n" ));
3526 FT_TRACE5(( "\n" ));
3527 #endif
3528 }
3529
3530
3531 /* Apply the complete hinting algorithm to a latin glyph. */
3532
3533 static FT_Error
3534 af_latin_hints_apply( FT_UInt glyph_index,
3535 AF_GlyphHints hints,
3536 FT_Outline* outline,
3537 AF_LatinMetrics metrics )
3538 {
3539 FT_Error error;
3540 int dim;
3541
3542 AF_LatinAxis axis;
3543
3544
3545 error = af_glyph_hints_reload( hints, outline );
3546 if ( error )
3547 goto Exit;
3548
3549 /* analyze glyph outline */
3550 if ( AF_HINTS_DO_HORIZONTAL( hints ) )
3551 {
3552 axis = &metrics->axis[AF_DIMENSION_HORZ];
3553 error = af_latin_hints_detect_features( hints,
3554 axis->width_count,
3555 axis->widths,
3556 AF_DIMENSION_HORZ );
3557 if ( error )
3558 goto Exit;
3559 }
3560
3561 if ( AF_HINTS_DO_VERTICAL( hints ) )
3562 {
3563 axis = &metrics->axis[AF_DIMENSION_VERT];
3564 error = af_latin_hints_detect_features( hints,
3565 axis->width_count,
3566 axis->widths,
3567 AF_DIMENSION_VERT );
3568 if ( error )
3569 goto Exit;
3570
3571 /* apply blue zones to base characters only */
3572 if ( !( metrics->root.globals->glyph_styles[glyph_index] & AF_NONBASE ) )
3573 af_latin_hints_compute_blue_edges( hints, metrics );
3574 }
3575
3576 /* grid-fit the outline */
3577 for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
3578 {
3579 #ifdef AF_CONFIG_OPTION_USE_WARPER
3580 if ( dim == AF_DIMENSION_HORZ &&
3581 metrics->root.scaler.render_mode == FT_RENDER_MODE_NORMAL &&
3582 AF_HINTS_DO_WARP( hints ) )
3583 {
3584 AF_WarperRec warper;
3585 FT_Fixed scale;
3586 FT_Pos delta;
3587
3588
3589 af_warper_compute( &warper, hints, (AF_Dimension)dim,
3590 &scale, &delta );
3591 af_glyph_hints_scale_dim( hints, (AF_Dimension)dim,
3592 scale, delta );
3593 continue;
3594 }
3595 #endif /* AF_CONFIG_OPTION_USE_WARPER */
3596
3597 if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) ||
3598 ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) ) )
3599 {
3600 af_latin_hint_edges( hints, (AF_Dimension)dim );
3601 af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim );
3602 af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim );
3603 af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim );
3604 }
3605 }
3606
3607 af_glyph_hints_save( hints, outline );
3608
3609 Exit:
3610 return error;
3611 }
3612
3613
3614 /*************************************************************************/
3615 /*************************************************************************/
3616 /***** *****/
3617 /***** L A T I N S C R I P T C L A S S *****/
3618 /***** *****/
3619 /*************************************************************************/
3620 /*************************************************************************/
3621
3622
3623 AF_DEFINE_WRITING_SYSTEM_CLASS(
3624 af_latin_writing_system_class,
3625
3626 AF_WRITING_SYSTEM_LATIN,
3627
3628 sizeof ( AF_LatinMetricsRec ),
3629
3630 (AF_WritingSystem_InitMetricsFunc) af_latin_metrics_init, /* style_metrics_init */
3631 (AF_WritingSystem_ScaleMetricsFunc)af_latin_metrics_scale, /* style_metrics_scale */
3632 (AF_WritingSystem_DoneMetricsFunc) NULL, /* style_metrics_done */
3633 (AF_WritingSystem_GetStdWidthsFunc)af_latin_get_standard_widths, /* style_metrics_getstdw */
3634
3635 (AF_WritingSystem_InitHintsFunc) af_latin_hints_init, /* style_hints_init */
3636 (AF_WritingSystem_ApplyHintsFunc) af_latin_hints_apply /* style_hints_apply */
3637 )
3638
3639
3640 /* END */