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1 /***************************************************************************/
2 /* */
3 /* ahglyph.c */
4 /* */
5 /* Routines used to load and analyze a given glyph before hinting */
6 /* (body). */
7 /* */
8 /* Copyright 2000 Catharon Productions Inc. */
9 /* Author: David Turner */
10 /* */
11 /* This file is part of the Catharon Typography Project and shall only */
12 /* be used, modified, and distributed under the terms of the Catharon */
13 /* Open Source License that should come with this file under the name */
14 /* `CatharonLicense.txt'. By continuing to use, modify, or distribute */
15 /* this file you indicate that you have read the license and */
16 /* understand and accept it fully. */
17 /* */
18 /* Note that this license is compatible with the FreeType license. */
19 /* */
20 /***************************************************************************/
21
22
23 #ifdef FT_FLAT_COMPILE
24
25 #include "ahglyph.h"
26 #include "ahangles.h"
27 #include "ahglobal.h"
28
29 #else
30
31 #include <autohint/ahglyph.h>
32 #include <autohint/ahangles.h>
33 #include <autohint/ahglobal.h>
34
35 #endif
36
37
38 #include <stdio.h>
39
40
41 #define xxxAH_DEBUG_GLYPH
42
43
44 /* compute the direction value of a given vector.. */
45 static
46 AH_Direction ah_compute_direction( FT_Pos dx,
47 FT_Pos dy )
48 {
49 AH_Direction dir;
50 FT_Pos ax = ABS( dx );
51 FT_Pos ay = ABS( dy );
52
53
54 dir = ah_dir_none;
55
56 /* test for vertical direction */
57 if ( ax * 12 < ay )
58 {
59 dir = dy > 0 ? ah_dir_up : ah_dir_down;
60 }
61 /* test for horizontal direction */
62 else if ( ay * 12 < ax )
63 {
64 dir = dx > 0 ? ah_dir_right : ah_dir_left;
65 }
66
67 return dir;
68 }
69
70
71 /*************************************************************************/
72 /* */
73 /* <Function> */
74 /* ah_outline_new */
75 /* */
76 /* <Description> */
77 /* Creates a new and empty AH_Outline object. */
78 /* */
79 LOCAL_FUNC
80 FT_Error ah_outline_new( FT_Memory memory,
81 AH_Outline** aoutline )
82 {
83 FT_Error error;
84 AH_Outline* outline;
85
86
87 if ( !ALLOC( outline, sizeof ( *outline ) ) )
88 {
89 outline->memory = memory;
90 *aoutline = outline;
91 }
92
93 return error;
94 }
95
96
97 /*************************************************************************/
98 /* */
99 /* <Function> */
100 /* ah_outline_done */
101 /* */
102 /* <Description> */
103 /* Destroys a given AH_Outline object. */
104 /* */
105 LOCAL_FUNC
106 void ah_outline_done( AH_Outline* outline )
107 {
108 FT_Memory memory = outline->memory;
109
110
111 FREE( outline->horz_edges );
112 FREE( outline->horz_segments );
113 FREE( outline->contours );
114 FREE( outline->points );
115
116 FREE( outline );
117 }
118
119
120 /*************************************************************************/
121 /* */
122 /* <Function> */
123 /* ah_outline_save */
124 /* */
125 /* <Description> */
126 /* Saves the content of a given AH_Outline object into a face's glyph */
127 /* slot. */
128 /* */
129 LOCAL_FUNC
130 void ah_outline_save( AH_Outline* outline,
131 AH_Loader* gloader )
132 {
133 AH_Point* point = outline->points;
134 AH_Point* limit = point + outline->num_points;
135 FT_Vector* vec = gloader->current.outline.points;
136 char* tag = gloader->current.outline.tags;
137
138
139 /* we assume that the glyph loader has already been checked for storage */
140 for ( ; point < limit; point++, vec++, tag++ )
141 {
142 vec->x = point->x;
143 vec->y = point->y;
144
145 if ( point->flags & ah_flah_conic )
146 tag[0] = FT_Curve_Tag_Conic;
147 else if ( point->flags & ah_flah_cubic )
148 tag[0] = FT_Curve_Tag_Cubic;
149 else
150 tag[0] = FT_Curve_Tag_On;
151 }
152 }
153
154
155 /*************************************************************************/
156 /* */
157 /* <Function> */
158 /* ah_outline_load */
159 /* */
160 /* <Description> */
161 /* Loads an unscaled outline from a glyph slot into an AH_Outline */
162 /* object. */
163 /* */
164 LOCAL_FUNC
165 FT_Error ah_outline_load( AH_Outline* outline,
166 FT_Face face )
167 {
168 FT_Memory memory = outline->memory;
169 FT_Error error = FT_Err_Ok;
170 FT_Outline* source = &face->glyph->outline;
171 FT_Int num_points = source->n_points;
172 FT_Int num_contours = source->n_contours;
173 AH_Point* points;
174
175
176 /* check arguments */
177 if ( !face ||
178 !face->size ||
179 face->glyph->format != ft_glyph_format_outline )
180 return FT_Err_Invalid_Argument;
181
182 /* first of all, reallocate the contours array if necessary */
183 if ( num_contours > outline->max_contours )
184 {
185 FT_Int new_contours = ( num_contours + 3 ) & -4;
186
187
188 if ( REALLOC_ARRAY( outline->contours, outline->max_contours,
189 new_contours, AH_Point* ) )
190 goto Exit;
191
192 outline->max_contours = new_contours;
193 }
194
195 /* then, realloc the points, segments & edges arrays if needed */
196 if ( num_points > outline->max_points )
197 {
198 FT_Int news = ( num_points + 7 ) & -8;
199 FT_Int max = outline->max_points;
200
201
202 if ( REALLOC_ARRAY( outline->points, max, news, AH_Point ) ||
203 REALLOC_ARRAY( outline->horz_edges, max, news, AH_Edge ) ||
204 REALLOC_ARRAY( outline->horz_segments, max, news, AH_Segment ) )
205 goto Exit;
206
207 /* readjust some pointers */
208 outline->vert_edges = outline->horz_edges + ( news >> 1 );
209 outline->vert_segments = outline->horz_segments + ( news >> 1 );
210 outline->max_points = news;
211 }
212
213 outline->num_points = num_points;
214 outline->num_contours = num_contours;
215
216 outline->num_hedges = 0;
217 outline->num_vedges = 0;
218 outline->num_hsegments = 0;
219 outline->num_vsegments = 0;
220
221 /* Compute the vertical and horizontal major directions; this is */
222 /* currently done by inspecting the `ft_outline_reverse_fill' flag. */
223 /* However, some fonts have improper glyphs, and it'd be a good idea */
224 /* to be able to re-compute these values on the fly. */
225 outline->vert_major_dir = ah_dir_up;
226 outline->horz_major_dir = ah_dir_left;
227
228 if ( source->flags & ft_outline_reverse_fill )
229 {
230 outline->vert_major_dir = ah_dir_down;
231 outline->horz_major_dir = ah_dir_right;
232 }
233
234 outline->x_scale = face->size->metrics.x_scale;
235 outline->y_scale = face->size->metrics.y_scale;
236
237 points = outline->points;
238
239 {
240 /* do one thing at a time -- it is easier to understand, and */
241 /* the code is clearer */
242 AH_Point* point = points;
243 AH_Point* limit = point + outline->num_points;
244
245
246 /* compute coordinates */
247 {
248 FT_Vector* vec = source->points;
249 FT_Fixed x_scale = outline->x_scale;
250 FT_Fixed y_scale = outline->y_scale;
251
252
253 for (; point < limit; vec++, point++ )
254 {
255 point->fx = vec->x;
256 point->fy = vec->y;
257 point->ox = point->x = FT_MulFix( vec->x, x_scale );
258 point->oy = point->y = FT_MulFix( vec->y, y_scale );
259
260 point->flags = 0;
261 }
262 }
263
264 /* compute Bezier flags */
265 {
266 char* tag = source->tags;
267
268
269 for ( point = points; point < limit; point++, tag++ )
270 {
271 switch ( FT_CURVE_TAG( *tag ) )
272 {
273 case FT_Curve_Tag_Conic:
274 point->flags = ah_flah_conic; break;
275 case FT_Curve_Tag_Cubic:
276 point->flags = ah_flah_cubic; break;
277 default:
278 ;
279 }
280 }
281 }
282
283 /* compute `next' and `prev' */
284 {
285 FT_Int contour_index;
286 AH_Point* prev;
287 AH_Point* first;
288 AH_Point* end;
289
290
291 contour_index = 0;
292
293 first = points;
294 end = points + source->contours[0];
295 prev = end;
296
297 for ( point = points; point < limit; point++ )
298 {
299 point->prev = prev;
300 if ( point < end )
301 {
302 point->next = point + 1;
303 prev = point;
304 }
305 else
306 {
307 point->next = first;
308 contour_index++;
309 if ( point + 1 < limit )
310 {
311 end = points + source->contours[contour_index];
312 first = point + 1;
313 prev = end;
314 }
315 }
316 }
317 }
318
319 /* set-up the contours array */
320 {
321 AH_Point** contour = outline->contours;
322 AH_Point** limit = contour + outline->num_contours;
323 short* end = source->contours;
324 short index = 0;
325
326
327 for ( ; contour < limit; contour++, end++ )
328 {
329 contour[0] = points + index;
330 index = end[0] + 1;
331 }
332 }
333
334 /* compute directions of in & out vectors */
335 {
336 for ( point = points; point < limit; point++ )
337 {
338 AH_Point* prev;
339 AH_Point* next;
340 FT_Vector vec;
341
342
343 prev = point->prev;
344 vec.x = point->fx - prev->fx;
345 vec.y = point->fy - prev->fy;
346
347 point->in_dir = ah_compute_direction( vec.x, vec.y );
348
349 #ifndef AH_OPTION_NO_WEAK_INTERPOLATION
350 point->in_angle = ah_angle( &vec );
351 #endif
352
353 next = point->next;
354 vec.x = next->fx - point->fx;
355 vec.y = next->fy - point->fy;
356
357 point->out_dir = ah_compute_direction( vec.x, vec.y );
358
359 #ifndef AH_OPTION_NO_WEAK_INTERPOLATION
360 point->out_angle = ah_angle( &vec );
361
362 {
363 AH_Angle delta = point->in_angle - point->out_angle;
364
365
366 if ( delta < 0 )
367 delta = -delta;
368 if ( delta < 2 )
369 point->flags |= ah_flah_weak_interpolation;
370 }
371
372 #if 0
373 if ( point->flags & ( ah_flah_conic | ah_flah_cubic ) )
374 point->flags |= ah_flah_weak_interpolation;
375 #endif
376
377 #endif /* !AH_OPTION_NO_WEAK_INTERPOLATION */
378
379 #ifdef AH_OPTION_NO_STRONG_INTERPOLATION
380 point->flags |= ah_flah_weak_interpolation;
381 #endif
382 }
383 }
384 }
385
386 Exit:
387 return error;
388 }
389
390
391 LOCAL_FUNC
392 void ah_setup_uv( AH_Outline* outline,
393 AH_UV source )
394 {
395 AH_Point* point = outline->points;
396 AH_Point* limit = point + outline->num_points;
397
398
399 for ( ; point < limit; point++ )
400 {
401 FT_Pos u, v;
402
403
404 switch ( source )
405 {
406 case ah_uv_fxy:
407 u = point->fx;
408 v = point->fy;
409 break;
410 case ah_uv_fyx:
411 u = point->fy;
412 v = point->fx;
413 break;
414 case ah_uv_oxy:
415 u = point->ox;
416 v = point->oy;
417 break;
418 case ah_uv_oyx:
419 u = point->oy;
420 v = point->ox;
421 break;
422 case ah_uv_yx:
423 u = point->y;
424 v = point->x;
425 break;
426 case ah_uv_ox:
427 u = point->x;
428 v = point->ox;
429 break;
430 case ah_uv_oy:
431 u = point->y;
432 v = point->oy;
433 break;
434 default:
435 u = point->x;
436 v = point->y;
437 break;
438 }
439 point->u = u;
440 point->v = v;
441 }
442 }
443
444
445 LOCAL_FUNC
446 void ah_outline_compute_segments( AH_Outline* outline )
447 {
448 int dimension;
449 AH_Segment* segments;
450 FT_Int* p_num_segments;
451 AH_Direction segment_dir;
452 AH_Direction major_dir;
453
454
455 segments = outline->horz_segments;
456 p_num_segments = &outline->num_hsegments;
457 major_dir = ah_dir_right; /* This value must be positive! */
458 segment_dir = major_dir;
459
460 /* set up (u,v) in each point */
461 ah_setup_uv( outline, ah_uv_fyx );
462
463 for ( dimension = 1; dimension >= 0; dimension-- )
464 {
465 AH_Point** contour = outline->contours;
466 AH_Point** contour_limit = contour + outline->num_contours;
467 AH_Segment* segment = segments;
468 FT_Int num_segments = 0;
469
470 #ifdef AH_HINT_METRICS
471 AH_Point* min_point = 0;
472 AH_Point* max_point = 0;
473 FT_Pos min_coord = 32000;
474 FT_Pos max_coord = -32000;
475 #endif
476
477
478 /* do each contour separately */
479 for ( ; contour < contour_limit; contour++ )
480 {
481 AH_Point* point = contour[0];
482 AH_Point* last = point->prev;
483 int on_edge = 0;
484 FT_Pos min_pos = +32000; /* minimum segment pos != min_coord */
485 FT_Pos max_pos = -32000; /* maximum segment pos != max_coord */
486 FT_Bool passed;
487
488
489 #ifdef AH_HINT_METRICS
490 if ( point->u < min_coord )
491 {
492 min_coord = point->u;
493 min_point = point;
494 }
495 if ( point->u > max_coord )
496 {
497 max_coord = point->u;
498 max_point = point;
499 }
500 #endif
501
502 if ( point == last ) /* skip singletons -- just in case? */
503 continue;
504
505 if ( ABS( last->out_dir ) == major_dir &&
506 ABS( point->out_dir ) == major_dir )
507 {
508 /* we are already on an edge, try to locate its start */
509 last = point;
510
511 for (;;)
512 {
513 point = point->prev;
514 if ( ABS( point->out_dir ) != major_dir )
515 {
516 point = point->next;
517 break;
518 }
519 if ( point == last )
520 break;
521 }
522
523 }
524
525 last = point;
526 passed = 0;
527
528 for (;;)
529 {
530 FT_Pos u, v;
531
532
533 if ( on_edge )
534 {
535 u = point->u;
536 if ( u < min_pos )
537 min_pos = u;
538 if ( u > max_pos )
539 max_pos = u;
540
541 if ( point->out_dir != segment_dir || point == last )
542 {
543 /* we are just leaving an edge; record a new segment! */
544 segment->last = point;
545 segment->pos = ( min_pos + max_pos ) >> 1;
546
547 /* a segment is round if either its first or last point */
548 /* is a control point */
549 if ( ( segment->first->flags | point->flags ) &
550 ah_flah_control )
551 segment->flags |= ah_edge_round;
552
553 /* compute segment size */
554 min_pos = max_pos = point->v;
555
556 v = segment->first->v;
557 if ( v < min_pos )
558 min_pos = v;
559 if ( v > max_pos )
560 max_pos = v;
561
562 segment->min_coord = min_pos;
563 segment->max_coord = max_pos;
564
565 on_edge = 0;
566 num_segments++;
567 segment++;
568 /* fallthrough */
569 }
570 }
571
572 /* now exit if we are at the start/end point */
573 if ( point == last )
574 {
575 if ( passed )
576 break;
577 passed = 1;
578 }
579
580 if ( !on_edge && ABS( point->out_dir ) == major_dir )
581 {
582 /* this is the start of a new segment! */
583 segment_dir = point->out_dir;
584
585 /* clear all segment fields */
586 memset( segment, 0, sizeof ( *segment ) );
587
588 segment->dir = segment_dir;
589 segment->flags = ah_edge_normal;
590 min_pos = max_pos = point->u;
591 segment->first = point;
592 segment->last = point;
593 segment->contour = contour;
594 on_edge = 1;
595
596 if ( point == max_point )
597 max_point = 0;
598
599 if ( point == min_point )
600 min_point = 0;
601 }
602
603 point = point->next;
604 }
605
606 } /* contours */
607
608 #ifdef AH_HINT_METRICS
609 /* we need to ensure that there are edges on the left-most and */
610 /* right-most points of the glyph in order to hint the metrics; */
611 /* we do this by inserting fake segments when needed */
612 if ( dimension == 0 )
613 {
614 AH_Point* point = outline->points;
615 AH_Point* limit = point + outline->num_points;
616
617 AH_Point* min_point = 0;
618 AH_Point* max_point = 0;
619 FT_Pos min_pos = 32000;
620 FT_Pos max_pos = -32000;
621
622
623 /* compute minimum and maximum points */
624 for ( ; point < limit; point++ )
625 {
626 FT_Pos x = point->fx;
627
628
629 if ( x < min_pos )
630 {
631 min_pos = x;
632 min_point = point;
633 }
634 if ( x > max_pos )
635 {
636 max_pos = x;
637 max_point = point;
638 }
639 }
640
641 /* insert minimum segment */
642 if ( min_point )
643 {
644 /* clear all segment fields */
645 memset( segment, 0, sizeof ( *segment ) );
646
647 segment->dir = segment_dir;
648 segment->flags = ah_edge_normal;
649 segment->first = min_point;
650 segment->last = min_point;
651 segment->pos = min_pos;
652
653 num_segments++;
654 segment++;
655 }
656
657 /* insert maximum segment */
658 if ( max_point )
659 {
660 /* clear all segment fields */
661 memset( segment, 0, sizeof ( *segment ) );
662
663 segment->dir = segment_dir;
664 segment->flags = ah_edge_normal;
665 segment->first = max_point;
666 segment->last = max_point;
667 segment->pos = max_pos;
668
669 num_segments++;
670 segment++;
671 }
672 }
673 #endif /* AH_HINT_METRICS */
674
675 *p_num_segments = num_segments;
676
677 segments = outline->vert_segments;
678 major_dir = ah_dir_up;
679 p_num_segments = &outline->num_vsegments;
680 ah_setup_uv( outline, ah_uv_fxy );
681 }
682 }
683
684
685 LOCAL_FUNC
686 void ah_outline_link_segments( AH_Outline* outline )
687 {
688 AH_Segment* segments;
689 AH_Segment* limit;
690 int dimension;
691
692
693 ah_setup_uv( outline, ah_uv_fyx );
694
695 segments = outline->horz_segments;
696 limit = segments + outline->num_hsegments;
697
698 for ( dimension = 1; dimension >= 0; dimension-- )
699 {
700 AH_Segment* seg1;
701 AH_Segment* seg2;
702
703
704 /* now compare each segment to the others */
705 for ( seg1 = segments; seg1 < limit; seg1++ )
706 {
707 FT_Pos best_score = 32000;
708 AH_Segment* best_segment = 0;
709
710
711 /* the fake segments are introduced to hint the metrics -- */
712 /* we must never link them to anything */
713 if ( seg1->first == seg1->last )
714 continue;
715
716 for ( seg2 = segments; seg2 < limit; seg2++ )
717 if ( seg1 != seg2 && seg1->dir + seg2->dir == 0 )
718 {
719 FT_Pos pos1 = seg1->pos;
720 FT_Pos pos2 = seg2->pos;
721 FT_Bool is_dir;
722 FT_Bool is_pos;
723
724
725 /* check that the segments are correctly oriented and */
726 /* positioned to form a black distance */
727
728 is_dir = ( seg1->dir == outline->horz_major_dir ||
729 seg1->dir == outline->vert_major_dir );
730 is_pos = pos1 > pos2;
731
732 if ( pos1 == pos2 || !(is_dir ^ is_pos) )
733 continue;
734
735 /* Check the two segments. We now have a better algorithm */
736 /* that doesn't rely on the segment points themselves but */
737 /* on their relative position. This gets rids of many */
738 /* unpleasant artefacts and incorrect stem/serifs */
739 /* computations. */
740
741 /* first of all, compute the size of the `common' height */
742 {
743 FT_Pos min = seg1->min_coord;
744 FT_Pos max = seg1->max_coord;
745 FT_Pos len, score;
746 FT_Pos size1, size2;
747
748
749 size1 = max - min;
750 size2 = seg2->max_coord - seg2->min_coord;
751
752 if ( min < seg2->min_coord )
753 min = seg2->min_coord;
754
755 if ( max < seg2->max_coord )
756 max = seg2->max_coord;
757
758 len = max - min;
759 score = seg2->pos - seg1->pos;
760 if ( score < 0 )
761 score = -score;
762
763 /* before comparing the scores, take care that the segments */
764 /* are really facing each other (often not for italics..) */
765 if ( 4 * len >= size1 && 4 * len >= size2 )
766 if ( score < best_score )
767 {
768 best_score = score;
769 best_segment = seg2;
770 }
771 }
772 }
773
774 if ( best_segment )
775 {
776 seg1->link = best_segment;
777 seg1->score = best_score;
778
779 best_segment->num_linked++;
780 }
781
782
783 } /* edges 1 */
784
785 /* now, compute the `serif' segments */
786 for ( seg1 = segments; seg1 < limit; seg1++ )
787 {
788 seg2 = seg1->link;
789
790 if ( seg2 && seg2->link != seg1 )
791 {
792 seg1->link = 0;
793 seg1->serif = seg2->link;
794 }
795 }
796
797 ah_setup_uv( outline, ah_uv_fxy );
798
799 segments = outline->vert_segments;
800 limit = segments + outline->num_vsegments;
801 }
802 }
803
804
805 #ifdef AH_DEBUG_GLYPH
806
807 /* A function used to dump the array of linked segments */
808 void ah_dump_segments( AH_Outline* outline )
809 {
810 AH_Segment* segments;
811 AH_Segment* limit;
812 AH_Point* points;
813 FT_Int dimension;
814
815
816 points = outline->points;
817 segments = outline->horz_segments;
818 limit = segments + outline->num_hsegments;
819
820 for ( dimension = 1; dimension >= 0; dimension-- )
821 {
822 AH_Segment* seg;
823
824
825 printf ( "Table of %s segments:\n",
826 !dimension ? "vertical" : "horizontal" );
827 printf ( " [ index | pos | dir | link | serif |"
828 " numl | first | start ]\n" );
829
830 for ( seg = segments; seg < limit; seg++ )
831 {
832 printf ( " [ %5d | %4d | %5s | %4d | %5d | %4d | %5d | %5d ]\n",
833 seg - segments,
834 (int)seg->pos,
835 seg->dir == ah_dir_up
836 ? "up"
837 : ( seg->dir == ah_dir_down
838 ? "down"
839 : ( seg->dir == ah_dir_left
840 ? "left"
841 : ( seg->dir == ah_dir_right
842 ? "right"
843 : "none" ) ) ),
844 seg->link ? (seg->link-segments) : -1,
845 seg->serif ? (seg->serif-segments) : -1,
846 (int)seg->num_linked,
847 seg->first - points,
848 seg->last - points );
849 }
850
851 segments = outline->vert_segments;
852 limit = segments + outline->num_vsegments;
853 }
854 }
855
856 #endif /* AH_DEBUG_GLYPH */
857
858
859 static
860 void ah_outline_compute_edges( AH_Outline* outline )
861 {
862 AH_Edge* edges;
863 AH_Segment* segments;
864 AH_Segment* segment_limit;
865 AH_Direction up_dir;
866 FT_Int* p_num_edges;
867 FT_Int dimension;
868 FT_Fixed scale;
869 FT_Pos edge_distance_threshold;
870
871
872 edges = outline->horz_edges;
873 segments = outline->horz_segments;
874 segment_limit = segments + outline->num_hsegments;
875 p_num_edges = &outline->num_hedges;
876 up_dir = ah_dir_right;
877 scale = outline->y_scale;
878
879 for ( dimension = 1; dimension >= 0; dimension-- )
880 {
881 AH_Edge* edge;
882 AH_Edge* edge_limit; /* really == edge + num_edges */
883 AH_Segment* seg;
884
885
886 /*********************************************************************/
887 /* */
888 /* We will begin by generating a sorted table of edges for the */
889 /* current direction. To do so, we simply scan each segment and try */
890 /* to find an edge in our table that corresponds to its position. */
891 /* */
892 /* If no edge is found, we create and insert a new edge in the */
893 /* sorted table. Otherwise, we simply add the segment to the edge's */
894 /* list which will be processed in the second step to compute the */
895 /* edge's properties. */
896 /* */
897 /* Note that the edges table is sorted along the segment/edge */
898 /* position. */
899 /* */
900 /*********************************************************************/
901
902 edge_distance_threshold = FT_MulFix( outline->edge_distance_threshold,
903 scale );
904 if ( edge_distance_threshold > 64 / 4 )
905 edge_distance_threshold = 64 / 4;
906
907 edge_limit = edges;
908 for ( seg = segments; seg < segment_limit; seg++ )
909 {
910 AH_Edge* found = 0;
911
912
913 /* look for an edge corresponding to the segment */
914 for ( edge = edges; edge < edge_limit; edge++ )
915 {
916 FT_Pos dist;
917
918
919 dist = seg->pos - edge->fpos;
920 if ( dist < 0 )
921 dist = -dist;
922
923 dist = FT_MulFix( dist, scale );
924 if ( dist < edge_distance_threshold )
925 {
926 found = edge;
927 break;
928 }
929 }
930
931 if ( !found )
932 {
933 /* insert a new edge in the list and */
934 /* sort according to the position */
935 while ( edge > edges && edge[-1].fpos > seg->pos )
936 {
937 edge[0] = edge[-1];
938 edge--;
939 }
940 edge_limit++;
941
942 /* clear all edge fields */
943 memset( edge, 0, sizeof ( *edge ) );
944
945 /* add the segment to the new edge's list */
946 edge->first = seg;
947 edge->last = seg;
948 edge->fpos = seg->pos;
949 edge->opos = edge->pos = FT_MulFix( seg->pos, scale );
950 seg->edge_next = seg;
951 }
952 else
953 {
954 /* if an edge was found, simply add the segment to the edge's */
955 /* list */
956 seg->edge_next = edge->first;
957 edge->last->edge_next = seg;
958 edge->last = seg;
959 }
960 }
961
962 *p_num_edges = edge_limit - edges;
963
964
965 /*********************************************************************/
966 /* */
967 /* Good, we will now compute each edge's properties according to */
968 /* segments found on its position. Basically, these are: */
969 /* */
970 /* - edge's main direction */
971 /* - stem edge, serif edge or both (which defaults to stem then) */
972 /* - rounded edge, straigth or both (which defaults to straight) */
973 /* - link for edge */
974 /* */
975 /*********************************************************************/
976
977 /* first of all, set the `edge' field in each segment -- this is */
978 /* required in order to compute edge links */
979 for ( edge = edges; edge < edge_limit; edge++ )
980 {
981 seg = edge->first;
982 if ( seg )
983 do
984 {
985 seg->edge = edge;
986 seg = seg->edge_next;
987 }
988 while ( seg != edge->first );
989 }
990
991 /* now, compute each edge properties */
992 for ( edge = edges; edge < edge_limit; edge++ )
993 {
994 int is_round = 0; /* does it contain round segments? */
995 int is_straight = 0; /* does it contain straight segments? */
996 int ups = 0; /* number of upwards segments */
997 int downs = 0; /* number of downwards segments */
998
999
1000 seg = edge->first;
1001
1002 do
1003 {
1004 FT_Bool is_serif;
1005
1006
1007 /* check for roundness of segment */
1008 if ( seg->flags & ah_edge_round )
1009 is_round++;
1010 else
1011 is_straight++;
1012
1013 /* check for segment direction */
1014 if ( seg->dir == up_dir )
1015 ups += seg->max_coord-seg->min_coord;
1016 else
1017 downs += seg->max_coord-seg->min_coord;
1018
1019 /* check for links -- if seg->serif is set, then seg->link must */
1020 /* be ignored */
1021 is_serif = seg->serif && seg->serif->edge != edge;
1022
1023 if ( seg->link || is_serif )
1024 {
1025 AH_Edge* edge2;
1026 AH_Segment* seg2;
1027
1028
1029 edge2 = edge->link;
1030 seg2 = seg->link;
1031
1032 if ( is_serif )
1033 {
1034 seg2 = seg->serif;
1035 edge2 = edge->serif;
1036 }
1037
1038 if ( edge2 )
1039 {
1040 FT_Pos edge_delta;
1041 FT_Pos seg_delta;
1042
1043
1044 edge_delta = edge->fpos - edge2->fpos;
1045 if ( edge_delta < 0 )
1046 edge_delta = -edge_delta;
1047
1048 seg_delta = seg->pos - seg2->pos;
1049 if ( seg_delta < 0 )
1050 seg_delta = -seg_delta;
1051
1052 if ( seg_delta < edge_delta )
1053 edge2 = seg2->edge;
1054 }
1055 else
1056 edge2 = seg2->edge;
1057
1058 if ( is_serif )
1059 edge->serif = edge2;
1060 else
1061 edge->link = edge2;
1062 }
1063
1064 seg = seg->edge_next;
1065
1066 } while ( seg != edge->first );
1067
1068 /* set the round/straight flags */
1069 edge->flags = ah_edge_normal;
1070
1071 if ( is_straight == 0 && is_round )
1072 edge->flags |= ah_edge_round;
1073
1074 /* set the edge's main direction */
1075 edge->dir = ah_dir_none;
1076
1077 if ( ups > downs )
1078 edge->dir = up_dir;
1079
1080 else if ( ups < downs )
1081 edge->dir = - up_dir;
1082
1083 else if ( ups == downs )
1084 edge->dir = 0; /* both up and down !! */
1085
1086 /* gets rid of serifs if link is set */
1087 /* XXX: This gets rid of many unpleasant artefacts! */
1088 /* Example: the `c' in cour.pfa at size 13 */
1089
1090 if ( edge->serif && edge->link )
1091 edge->serif = 0;
1092 }
1093
1094 edges = outline->vert_edges;
1095 segments = outline->vert_segments;
1096 segment_limit = segments + outline->num_vsegments;
1097 p_num_edges = &outline->num_vedges;
1098 up_dir = ah_dir_up;
1099 scale = outline->x_scale;
1100 }
1101 }
1102
1103
1104 /*************************************************************************/
1105 /* */
1106 /* <Function> */
1107 /* ah_outline_detect_features */
1108 /* */
1109 /* <Description> */
1110 /* Performs feature detection on a given AH_Outline object. */
1111 /* */
1112 LOCAL_FUNC
1113 void ah_outline_detect_features( AH_Outline* outline )
1114 {
1115 ah_outline_compute_segments( outline );
1116 ah_outline_link_segments ( outline );
1117 ah_outline_compute_edges ( outline );
1118 }
1119
1120
1121 /*************************************************************************/
1122 /* */
1123 /* <Function> */
1124 /* ah_outline_compute_blue_edges */
1125 /* */
1126 /* <Description> */
1127 /* Computes the `blue edges' in a given outline (i.e. those that must */
1128 /* be snapped to a blue zone edge (top or bottom). */
1129 /* */
1130 LOCAL_FUNC
1131 void ah_outline_compute_blue_edges( AH_Outline* outline,
1132 AH_Face_Globals* face_globals )
1133 {
1134 AH_Edge* edge = outline->horz_edges;
1135 AH_Edge* limit = edge + outline->num_hedges;
1136 AH_Globals* globals = &face_globals->design;
1137 FT_Fixed y_scale = outline->y_scale;
1138
1139
1140 /* compute for each horizontal edge, which blue zone is closer */
1141 for ( ; edge < limit; edge++ )
1142 {
1143 AH_Blue blue;
1144 FT_Pos* best_blue = 0;
1145 FT_Pos best_dist; /* initial threshold */
1146
1147
1148 /* compute the initial threshold as a fraction of the EM size */
1149 best_dist = FT_MulFix( face_globals->face->units_per_EM / 40, y_scale );
1150 if ( best_dist > 64 / 4 )
1151 best_dist = 64 / 4;
1152
1153 for ( blue = ah_blue_capital_top; blue < ah_blue_max; blue++ )
1154 {
1155 /* if it is a top zone, check for right edges -- if it is a bottom */
1156 /* zone, check for left edges */
1157 /* */
1158 /* of course, that's for TrueType XXX */
1159 FT_Bool is_top_blue = AH_IS_TOP_BLUE( blue );
1160 FT_Bool is_major_dir = edge->dir == outline->horz_major_dir;
1161
1162
1163 /* if it is a top zone, the edge must be against the major */
1164 /* direction; if it is a bottom zone, it must be in the major */
1165 /* direction */
1166 if ( is_top_blue ^ is_major_dir )
1167 {
1168 FT_Pos dist;
1169 FT_Pos* blue_pos = globals->blue_refs + blue;
1170
1171
1172 /* first of all, compare it to the reference position */
1173 dist = edge->fpos - *blue_pos;
1174 if ( dist < 0 )
1175 dist = -dist;
1176
1177 dist = FT_MulFix( dist, y_scale );
1178 if ( dist < best_dist )
1179 {
1180 best_dist = dist;
1181 best_blue = blue_pos;
1182 }
1183
1184 /* now, compare it to the overshoot position if the edge is */
1185 /* rounded, and if the edge is over the reference position of a */
1186 /* top zone, or under the reference position of a bottom zone */
1187 if ( edge->flags & ah_edge_round && dist != 0 )
1188 {
1189 FT_Bool is_under_ref = edge->fpos < *blue_pos;
1190
1191
1192 if ( is_top_blue ^ is_under_ref )
1193 {
1194 blue_pos = globals->blue_shoots + blue;
1195 dist = edge->fpos - *blue_pos;
1196 if ( dist < 0 )
1197 dist = -dist;
1198
1199 dist = FT_MulFix( dist, y_scale );
1200 if ( dist < best_dist )
1201 {
1202 best_dist = dist;
1203 best_blue = blue_pos;
1204 }
1205 }
1206 }
1207 }
1208 }
1209
1210 if ( best_blue )
1211 edge->blue_edge = best_blue;
1212 }
1213 }
1214
1215
1216 /*************************************************************************/
1217 /* */
1218 /* <Function> */
1219 /* ah_outline_scale_blue_edges */
1220 /* */
1221 /* <Description> */
1222 /* This functions must be called before hinting in order to re-adjust */
1223 /* the contents of the detected edges (basically change the `blue */
1224 /* edge' pointer from `design units' to `scaled ones'). */
1225 /* */
1226 LOCAL_FUNC
1227 void ah_outline_scale_blue_edges( AH_Outline* outline,
1228 AH_Face_Globals* globals )
1229 {
1230 AH_Edge* edge = outline->horz_edges;
1231 AH_Edge* limit = edge + outline->num_hedges;
1232 FT_Int delta;
1233
1234
1235 delta = globals->scaled.blue_refs - globals->design.blue_refs;
1236
1237 for ( ; edge < limit; edge++ )
1238 {
1239 if ( edge->blue_edge )
1240 edge->blue_edge += delta;
1241 }
1242 }
1243
1244
1245 #ifdef AH_DEBUG_GLYPH
1246
1247 void ah_dump_edges( AH_Outline* outline )
1248 {
1249 AH_Edge* edges;
1250 AH_Edge* limit;
1251 AH_Segment* segments;
1252 FT_Int dimension;
1253
1254
1255 edges = outline->horz_edges;
1256 limit = edges + outline->num_hedges;
1257 segments = outline->horz_segments;
1258
1259 for ( dimension = 1; dimension >= 0; dimension-- )
1260 {
1261 AH_Edge* edge;
1262
1263
1264 printf ( "Table of %s edges:\n",
1265 !dimension ? "vertical" : "horizontal" );
1266 printf ( " [ index | pos | dir | link |"
1267 " serif | blue | opos | pos ]\n" );
1268
1269 for ( edge = edges; edge < limit; edge++ )
1270 {
1271 printf ( " [ %5d | %4d | %5s | %4d | %5d | %c | %5.2f | %5.2f ]\n",
1272 edge - edges,
1273 (int)edge->fpos,
1274 edge->dir == ah_dir_up
1275 ? "up"
1276 : ( edge->dir == ah_dir_down
1277 ? "down"
1278 : ( edge->dir == ah_dir_left
1279 ? "left"
1280 : ( edge->dir == ah_dir_right
1281 ? "right"
1282 : "none" ) ) ),
1283 edge->link ? ( edge->link - edges ) : -1,
1284 edge->serif ? ( edge->serif - edges ) : -1,
1285 edge->blue_edge ? 'y' : 'n',
1286 edge->opos / 64.0,
1287 edge->pos / 64.0 );
1288 }
1289
1290 edges = outline->vert_edges;
1291 limit = edges + outline->num_vedges;
1292 segments = outline->vert_segments;
1293 }
1294 }
1295
1296 #endif /* AH_DEBUG_GLYPH */
1297
1298
1299 /* END */
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