Context Navigation

source: trunk/poppler/freetype2/src/autofit/aflatin.c @ 251

Last change on this file since 251 was 251, checked in by Eugene Romanenko, 13 years ago
PDF plugin: freetype library updated to version 2.3.5
File size: 65.1 KB

Line
1	/***************************************************************************/
2	/* */
3	/* aflatin.c */
4	/* */
5	/* Auto-fitter hinting routines for latin script (body). */
6	/* */
7	/* Copyright 2003, 2004, 2005, 2006, 2007 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 "aflatin.h"
20	#include "aferrors.h"
21
22
23	#ifdef AF_USE_WARPER
24	#include "afwarp.h"
25	#endif
26
27
28	/*************************************************************************/
29	/*************************************************************************/
30	/*** ***/
31	/*** L A T I N G L O B A L M E T R I C S ***/
32	/*** ***/
33	/*************************************************************************/
34	/*************************************************************************/
35
36	FT_LOCAL_DEF( void )
37	af_latin_metrics_init_widths( AF_LatinMetrics metrics,
38	FT_Face face,
39	FT_ULong charcode )
40	{
41	/* scan the array of segments in each direction */
42	AF_GlyphHintsRec hints[1];
43
44
45	af_glyph_hints_init( hints, face->memory );
46
47	metrics->axis[AF_DIMENSION_HORZ].width_count = 0;
48	metrics->axis[AF_DIMENSION_VERT].width_count = 0;
49
50	{
51	FT_Error error;
52	FT_UInt glyph_index;
53	int dim;
54	AF_LatinMetricsRec dummy[1];
55	AF_Scaler scaler = &dummy->root.scaler;
56
57
58	glyph_index = FT_Get_Char_Index( face, charcode );
59	if ( glyph_index == 0 )
60	goto Exit;
61
62	error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
63	if ( error \|\| face->glyph->outline.n_points <= 0 )
64	goto Exit;
65
66	FT_ZERO( dummy );
67
68	dummy->units_per_em = metrics->units_per_em;
69	scaler->x_scale = scaler->y_scale = 0x10000L;
70	scaler->x_delta = scaler->y_delta = 0;
71	scaler->face = face;
72	scaler->render_mode = FT_RENDER_MODE_NORMAL;
73	scaler->flags = 0;
74
75	af_glyph_hints_rescale( hints, (AF_ScriptMetrics)dummy );
76
77	error = af_glyph_hints_reload( hints, &face->glyph->outline, 0 );
78	if ( error )
79	goto Exit;
80
81	for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
82	{
83	AF_LatinAxis axis = &metrics->axis[dim];
84	AF_AxisHints axhints = &hints->axis[dim];
85	AF_Segment seg, limit, link;
86	FT_UInt num_widths = 0;
87
88
89	error = af_latin_hints_compute_segments( hints,
90	(AF_Dimension)dim );
91	if ( error )
92	goto Exit;
93
94	af_latin_hints_link_segments( hints,
95	(AF_Dimension)dim );
96
97	seg = axhints->segments;
98	limit = seg + axhints->num_segments;
99
100	for ( ; seg < limit; seg++ )
101	{
102	link = seg->link;
103
104	/* we only consider stem segments there! */
105	if ( link && link->link == seg && link > seg )
106	{
107	FT_Pos dist;
108
109
110	dist = seg->pos - link->pos;
111	if ( dist < 0 )
112	dist = -dist;
113
114	if ( num_widths < AF_LATIN_MAX_WIDTHS )
115	axis->widths[ num_widths++ ].org = dist;
116	}
117	}
118
119	af_sort_widths( num_widths, axis->widths );
120	axis->width_count = num_widths;
121	}
122
123	Exit:
124	for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
125	{
126	AF_LatinAxis axis = &metrics->axis[dim];
127	FT_Pos stdw;
128
129
130	stdw = ( axis->width_count > 0 )
131	? axis->widths[0].org
132	: AF_LATIN_CONSTANT( metrics, 50 );
133
134	/* let's try 20% of the smallest width */
135	axis->edge_distance_threshold = stdw / 5;
136	axis->standard_width = stdw;
137	axis->extra_light = 0;
138	}
139	}
140
141	af_glyph_hints_done( hints );
142	}
143
144
145
146	#define AF_LATIN_MAX_TEST_CHARACTERS 12
147
148
149	static const char* const af_latin_blue_chars[AF_LATIN_MAX_BLUES] =
150	{
151	"THEZOCQS",
152	"HEZLOCUS",
153	"fijkdbh",
154	"xzroesc",
155	"xzroesc",
156	"pqgjy"
157	};
158
159
160	static void
161	af_latin_metrics_init_blues( AF_LatinMetrics metrics,
162	FT_Face face )
163	{
164	FT_Pos flats [AF_LATIN_MAX_TEST_CHARACTERS];
165	FT_Pos rounds[AF_LATIN_MAX_TEST_CHARACTERS];
166	FT_Int num_flats;
167	FT_Int num_rounds;
168	FT_Int bb;
169	AF_LatinBlue blue;
170	FT_Error error;
171	AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT];
172	FT_GlyphSlot glyph = face->glyph;
173
174
175	/* we compute the blues simply by loading each character from the */
176	/* 'af_latin_blue_chars[blues]' string, then compute its top-most or */
177	/* bottom-most points (depending on `AF_IS_TOP_BLUE') */
178
179	AF_LOG(( "blue zones computation\n" ));
180	AF_LOG(( "------------------------------------------------\n" ));
181
182	for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ )
183	{
184	const char* p = af_latin_blue_chars[bb];
185	const char* limit = p + AF_LATIN_MAX_TEST_CHARACTERS;
186	FT_Pos* blue_ref;
187	FT_Pos* blue_shoot;
188
189
190	AF_LOG(( "blue %3d: ", bb ));
191
192	num_flats = 0;
193	num_rounds = 0;
194
195	for ( ; p < limit && *p; p++ )
196	{
197	FT_UInt glyph_index;
198	FT_Int best_point, best_y, best_first, best_last;
199	FT_Vector* points;
200	FT_Bool round = 0;
201
202
203	AF_LOG(( "'%c'", *p ));
204
205	/* load the character in the face -- skip unknown or empty ones */
206	glyph_index = FT_Get_Char_Index( face, (FT_UInt)*p );
207	if ( glyph_index == 0 )
208	continue;
209
210	error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
211	if ( error \|\| glyph->outline.n_points <= 0 )
212	continue;
213
214	/* now compute min or max point indices and coordinates */
215	points = glyph->outline.points;
216	best_point = -1;
217	best_y = 0; /* make compiler happy */
218	best_first = 0; /* ditto */
219	best_last = 0; /* ditto */
220
221	{
222	FT_Int nn;
223	FT_Int first = 0;
224	FT_Int last = -1;
225
226
227	for ( nn = 0; nn < glyph->outline.n_contours; first = last+1, nn++ )
228	{
229	FT_Int old_best_point = best_point;
230	FT_Int pp;
231
232
233	last = glyph->outline.contours[nn];
234
235	/* Avoid single-point contours since they are never rasterized. */
236	/* In some fonts, they correspond to mark attachment points */
237	/* which are way outside of the glyph's real outline. */
238	if ( last <= first )
239	continue;
240
241	if ( AF_LATIN_IS_TOP_BLUE( bb ) )
242	{
243	for ( pp = first; pp <= last; pp++ )
244	if ( best_point < 0 \|\| points[pp].y > best_y )
245	{
246	best_point = pp;
247	best_y = points[pp].y;
248	}
249	}
250	else
251	{
252	for ( pp = first; pp <= last; pp++ )
253	if ( best_point < 0 \|\| points[pp].y < best_y )
254	{
255	best_point = pp;
256	best_y = points[pp].y;
257	}
258	}
259
260	if ( best_point != old_best_point )
261	{
262	best_first = first;
263	best_last = last;
264	}
265	}
266	AF_LOG(( "%5d", best_y ));
267	}
268
269	/* now check whether the point belongs to a straight or round */
270	/* segment; we first need to find in which contour the extremum */
271	/* lies, then inspect its previous and next points */
272	if ( best_point >= 0 )
273	{
274	FT_Int prev, next;
275	FT_Pos dist;
276
277
278	/* now look for the previous and next points that are not on the */
279	/* same Y coordinate. Threshold the `closeness'... */
280	prev = best_point;
281	next = prev;
282
283	do
284	{
285	if ( prev > best_first )
286	prev--;
287	else
288	prev = best_last;
289
290	dist = points[prev].y - best_y;
291	if ( dist < -5 \|\| dist > 5 )
292	break;
293
294	} while ( prev != best_point );
295
296	do
297	{
298	if ( next < best_last )
299	next++;
300	else
301	next = best_first;
302
303	dist = points[next].y - best_y;
304	if ( dist < -5 \|\| dist > 5 )
305	break;
306
307	} while ( next != best_point );
308
309	/* now, set the `round' flag depending on the segment's kind */
310	round = FT_BOOL(
311	FT_CURVE_TAG( glyph->outline.tags[prev] ) != FT_CURVE_TAG_ON \|\|
312	FT_CURVE_TAG( glyph->outline.tags[next] ) != FT_CURVE_TAG_ON );
313
314	AF_LOG(( "%c ", round ? 'r' : 'f' ));
315	}
316
317	if ( round )
318	rounds[num_rounds++] = best_y;
319	else
320	flats[num_flats++] = best_y;
321	}
322
323	AF_LOG(( "\n" ));
324
325	if ( num_flats == 0 && num_rounds == 0 )
326	{
327	/*
328	* we couldn't find a single glyph to compute this blue zone,
329	* we will simply ignore it then
330	*/
331	AF_LOG(( "empty!\n" ));
332	continue;
333	}
334
335	/* we have computed the contents of the `rounds' and `flats' tables, */
336	/* now determine the reference and overshoot position of the blue -- */
337	/* we simply take the median value after a simple sort */
338	af_sort_pos( num_rounds, rounds );
339	af_sort_pos( num_flats, flats );
340
341	blue = & axis->blues[axis->blue_count];
342	blue_ref = & blue->ref.org;
343	blue_shoot = & blue->shoot.org;
344
345	axis->blue_count++;
346
347	if ( num_flats == 0 )
348	{
349	*blue_ref =
350	*blue_shoot = rounds[num_rounds / 2];
351	}
352	else if ( num_rounds == 0 )
353	{
354	*blue_ref =
355	*blue_shoot = flats[num_flats / 2];
356	}
357	else
358	{
359	*blue_ref = flats[num_flats / 2];
360	*blue_shoot = rounds[num_rounds / 2];
361	}
362
363	/* there are sometimes problems: if the overshoot position of top */
364	/* zones is under its reference position, or the opposite for bottom */
365	/* zones. We must thus check everything there and correct the errors */
366	if ( blue_shoot != blue_ref )
367	{
368	FT_Pos ref = *blue_ref;
369	FT_Pos shoot = *blue_shoot;
370	FT_Bool over_ref = FT_BOOL( shoot > ref );
371
372
373	if ( AF_LATIN_IS_TOP_BLUE( bb ) ^ over_ref )
374	blue_shoot = blue_ref = ( shoot + ref ) / 2;
375	}
376
377	blue->flags = 0;
378	if ( AF_LATIN_IS_TOP_BLUE( bb ) )
379	blue->flags \|= AF_LATIN_BLUE_TOP;
380
381	/*
382	* The following flags is used later to adjust the y and x scales
383	* in order to optimize the pixel grid alignment of the top of small
384	* letters.
385	*/
386	if ( bb == AF_LATIN_BLUE_SMALL_TOP )
387	blue->flags \|= AF_LATIN_BLUE_ADJUSTMENT;
388
389	AF_LOG(( "-- ref = %ld, shoot = %ld\n", blue_ref, blue_shoot ));
390	}
391
392	return;
393	}
394
395
396	FT_LOCAL_DEF( FT_Error )
397	af_latin_metrics_init( AF_LatinMetrics metrics,
398	FT_Face face )
399	{
400	FT_Error error = AF_Err_Ok;
401	FT_CharMap oldmap = face->charmap;
402	FT_UInt ee;
403
404	static const FT_Encoding latin_encodings[] =
405	{
406	FT_ENCODING_UNICODE,
407	FT_ENCODING_APPLE_ROMAN,
408	FT_ENCODING_ADOBE_STANDARD,
409	FT_ENCODING_ADOBE_LATIN_1,
410	FT_ENCODING_NONE /* end of list */
411	};
412
413
414	metrics->units_per_em = face->units_per_EM;
415
416	/* do we have a latin charmap in there? */
417	for ( ee = 0; latin_encodings[ee] != FT_ENCODING_NONE; ee++ )
418	{
419	error = FT_Select_Charmap( face, latin_encodings[ee] );
420	if ( !error )
421	break;
422	}
423
424	if ( !error )
425	{
426	/* For now, compute the standard width and height from the `o'. */
427	af_latin_metrics_init_widths( metrics, face, 'o' );
428	af_latin_metrics_init_blues( metrics, face );
429	}
430
431	FT_Set_Charmap( face, oldmap );
432	return AF_Err_Ok;
433	}
434
435
436	static void
437	af_latin_metrics_scale_dim( AF_LatinMetrics metrics,
438	AF_Scaler scaler,
439	AF_Dimension dim )
440	{
441	FT_Fixed scale;
442	FT_Pos delta;
443	AF_LatinAxis axis;
444	FT_UInt nn;
445
446
447	if ( dim == AF_DIMENSION_HORZ )
448	{
449	scale = scaler->x_scale;
450	delta = scaler->x_delta;
451	}
452	else
453	{
454	scale = scaler->y_scale;
455	delta = scaler->y_delta;
456	}
457
458	axis = &metrics->axis[dim];
459
460	if ( axis->org_scale == scale && axis->org_delta == delta )
461	return;
462
463	axis->org_scale = scale;
464	axis->org_delta = delta;
465
466	/*
467	* correct X and Y scale to optimize the alignment of the top of small
468	* letters to the pixel grid
469	*/
470	{
471	AF_LatinAxis Axis = &metrics->axis[AF_DIMENSION_VERT];
472	AF_LatinBlue blue = NULL;
473
474
475	for ( nn = 0; nn < Axis->blue_count; nn++ )
476	{
477	if ( Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT )
478	{
479	blue = &Axis->blues[nn];
480	break;
481	}
482	}
483
484	if ( blue )
485	{
486	FT_Pos scaled = FT_MulFix( blue->shoot.org, scaler->y_scale );
487	FT_Pos fitted = ( scaled + 40 ) & ~63;
488
489
490	if ( scaled != fitted )
491	{
492	#if 0
493	if ( dim == AF_DIMENSION_HORZ )
494	{
495	if ( fitted < scaled )
496	scale -= scale / 50; /* scale = 0.98 /
497	}
498	else
499	#endif
500	if ( dim == AF_DIMENSION_VERT )
501	{
502	scale = FT_MulDiv( scale, fitted, scaled );
503	}
504	}
505	}
506	}
507
508	axis->scale = scale;
509	axis->delta = delta;
510
511	if ( dim == AF_DIMENSION_HORZ )
512	{
513	metrics->root.scaler.x_scale = scale;
514	metrics->root.scaler.x_delta = delta;
515	}
516	else
517	{
518	metrics->root.scaler.y_scale = scale;
519	metrics->root.scaler.y_delta = delta;
520	}
521
522	/* scale the standard widths */
523	for ( nn = 0; nn < axis->width_count; nn++ )
524	{
525	AF_Width width = axis->widths + nn;
526
527
528	width->cur = FT_MulFix( width->org, scale );
529	width->fit = width->cur;
530	}
531
532	/* an extra-light axis corresponds to a standard width that is */
533	/* smaller than 0.75 pixels */
534	axis->extra_light =
535	(FT_Bool)( FT_MulFix( axis->standard_width, scale ) < 32 + 8 );
536
537	if ( dim == AF_DIMENSION_VERT )
538	{
539	/* scale the blue zones */
540	for ( nn = 0; nn < axis->blue_count; nn++ )
541	{
542	AF_LatinBlue blue = &axis->blues[nn];
543	FT_Pos dist;
544
545
546	blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta;
547	blue->ref.fit = blue->ref.cur;
548	blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta;
549	blue->shoot.fit = blue->shoot.cur;
550	blue->flags &= ~AF_LATIN_BLUE_ACTIVE;
551
552	/* a blue zone is only active if it is less than 3/4 pixels tall */
553	dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale );
554	if ( dist <= 48 && dist >= -48 )
555	{
556	FT_Pos delta1, delta2;
557
558
559	delta1 = blue->shoot.org - blue->ref.org;
560	delta2 = delta1;
561	if ( delta1 < 0 )
562	delta2 = -delta2;
563
564	delta2 = FT_MulFix( delta2, scale );
565
566	if ( delta2 < 32 )
567	delta2 = 0;
568	else if ( delta2 < 64 )
569	delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
570	else
571	delta2 = FT_PIX_ROUND( delta2 );
572
573	if ( delta1 < 0 )
574	delta2 = -delta2;
575
576	blue->ref.fit = FT_PIX_ROUND( blue->ref.cur );
577	blue->shoot.fit = blue->ref.fit + delta2;
578
579	blue->flags \|= AF_LATIN_BLUE_ACTIVE;
580	}
581	}
582	}
583	}
584
585
586	FT_LOCAL_DEF( void )
587	af_latin_metrics_scale( AF_LatinMetrics metrics,
588	AF_Scaler scaler )
589	{
590	metrics->root.scaler.render_mode = scaler->render_mode;
591	metrics->root.scaler.face = scaler->face;
592
593	af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ );
594	af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT );
595	}
596
597
598	/*************************************************************************/
599	/*************************************************************************/
600	/*** ***/
601	/*** L A T I N G L Y P H A N A L Y S I S ***/
602	/*** ***/
603	/*************************************************************************/
604	/*************************************************************************/
605
606	FT_LOCAL_DEF( FT_Error )
607	af_latin_hints_compute_segments( AF_GlyphHints hints,
608	AF_Dimension dim )
609	{
610	AF_AxisHints axis = &hints->axis[dim];
611	FT_Memory memory = hints->memory;
612	FT_Error error = AF_Err_Ok;
613	AF_Segment segment = NULL;
614	AF_SegmentRec seg0;
615	AF_Point* contour = hints->contours;
616	AF_Point* contour_limit = contour + hints->num_contours;
617	AF_Direction major_dir, segment_dir;
618
619
620	FT_ZERO( &seg0 );
621	seg0.score = 32000;
622	seg0.flags = AF_EDGE_NORMAL;
623
624	major_dir = (AF_Direction)FT_ABS( axis->major_dir );
625	segment_dir = major_dir;
626
627	axis->num_segments = 0;
628
629	/* set up (u,v) in each point */
630	if ( dim == AF_DIMENSION_HORZ )
631	{
632	AF_Point point = hints->points;
633	AF_Point limit = point + hints->num_points;
634
635
636	for ( ; point < limit; point++ )
637	{
638	point->u = point->fx;
639	point->v = point->fy;
640	}
641	}
642	else
643	{
644	AF_Point point = hints->points;
645	AF_Point limit = point + hints->num_points;
646
647
648	for ( ; point < limit; point++ )
649	{
650	point->u = point->fy;
651	point->v = point->fx;
652	}
653	}
654
655	/* do each contour separately */
656	for ( ; contour < contour_limit; contour++ )
657	{
658	AF_Point point = contour[0];
659	AF_Point last = point->prev;
660	int on_edge = 0;
661	FT_Pos min_pos = 32000; /* minimum segment pos != min_coord */
662	FT_Pos max_pos = -32000; /* maximum segment pos != max_coord */
663	FT_Bool passed;
664
665
666	if ( point == last ) /* skip singletons -- just in case */
667	continue;
668
669	if ( FT_ABS( last->out_dir ) == major_dir &&
670	FT_ABS( point->out_dir ) == major_dir )
671	{
672	/* we are already on an edge, try to locate its start */
673	last = point;
674
675	for (;;)
676	{
677	point = point->prev;
678	if ( FT_ABS( point->out_dir ) != major_dir )
679	{
680	point = point->next;
681	break;
682	}
683	if ( point == last )
684	break;
685	}
686	}
687
688	last = point;
689	passed = 0;
690
691	for (;;)
692	{
693	FT_Pos u, v;
694
695
696	if ( on_edge )
697	{
698	u = point->u;
699	if ( u < min_pos )
700	min_pos = u;
701	if ( u > max_pos )
702	max_pos = u;
703
704	if ( point->out_dir != segment_dir \|\| point == last )
705	{
706	/* we are just leaving an edge; record a new segment! */
707	segment->last = point;
708	segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 );
709
710	/* a segment is round if either its first or last point */
711	/* is a control point */
712	if ( ( segment->first->flags \| point->flags ) &
713	AF_FLAG_CONTROL )
714	segment->flags \|= AF_EDGE_ROUND;
715
716	/* compute segment size */
717	min_pos = max_pos = point->v;
718
719	v = segment->first->v;
720	if ( v < min_pos )
721	min_pos = v;
722	if ( v > max_pos )
723	max_pos = v;
724
725	segment->min_coord = (FT_Short)min_pos;
726	segment->max_coord = (FT_Short)max_pos;
727	segment->height = (FT_Short)( segment->max_coord -
728	segment->min_coord );
729
730	on_edge = 0;
731	segment = NULL;
732	/* fallthrough */
733	}
734	}
735
736	/* now exit if we are at the start/end point */
737	if ( point == last )
738	{
739	if ( passed )
740	break;
741	passed = 1;
742	}
743
744	if ( !on_edge && FT_ABS( point->out_dir ) == major_dir )
745	{
746	/* this is the start of a new segment! */
747	segment_dir = (AF_Direction)point->out_dir;
748
749	/* clear all segment fields */
750	error = af_axis_hints_new_segment( axis, memory, &segment );
751	if ( error )
752	goto Exit;
753
754	segment[0] = seg0;
755	segment->dir = (FT_Char)segment_dir;
756	min_pos = max_pos = point->u;
757	segment->first = point;
758	segment->last = point;
759	segment->contour = contour;
760	on_edge = 1;
761	}
762
763	point = point->next;
764	}
765
766	} /* contours */
767
768
769	/* now slightly increase the height of segments when this makes */
770	/* sense -- this is used to better detect and ignore serifs */
771	{
772	AF_Segment segments = axis->segments;
773	AF_Segment segments_end = segments + axis->num_segments;
774
775
776	for ( segment = segments; segment < segments_end; segment++ )
777	{
778	AF_Point first = segment->first;
779	AF_Point last = segment->last;
780	FT_Pos first_v = first->v;
781	FT_Pos last_v = last->v;
782
783
784	if ( first == last )
785	continue;
786
787	if ( first_v < last_v )
788	{
789	AF_Point p;
790
791
792	p = first->prev;
793	if ( p->v < first_v )
794	segment->height = (FT_Short)( segment->height +
795	( ( first_v - p->v ) >> 1 ) );
796
797	p = last->next;
798	if ( p->v > last_v )
799	segment->height = (FT_Short)( segment->height +
800	( ( p->v - last_v ) >> 1 ) );
801	}
802	else
803	{
804	AF_Point p;
805
806
807	p = first->prev;
808	if ( p->v > first_v )
809	segment->height = (FT_Short)( segment->height +
810	( ( p->v - first_v ) >> 1 ) );
811
812	p = last->next;
813	if ( p->v < last_v )
814	segment->height = (FT_Short)( segment->height +
815	( ( last_v - p->v ) >> 1 ) );
816	}
817	}
818	}
819
820	Exit:
821	return error;
822	}
823
824
825	FT_LOCAL_DEF( void )
826	af_latin_hints_link_segments( AF_GlyphHints hints,
827	AF_Dimension dim )
828	{
829	AF_AxisHints axis = &hints->axis[dim];
830	AF_Segment segments = axis->segments;
831	AF_Segment segment_limit = segments + axis->num_segments;
832	FT_Pos len_threshold, len_score;
833	AF_Segment seg1, seg2;
834
835
836	len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );
837	if ( len_threshold == 0 )
838	len_threshold = 1;
839
840	len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 );
841
842	/* now compare each segment to the others */
843	for ( seg1 = segments; seg1 < segment_limit; seg1++ )
844	{
845	/* the fake segments are introduced to hint the metrics -- */
846	/* we must never link them to anything */
847	if ( seg1->dir != axis->major_dir \|\| seg1->first == seg1->last )
848	continue;
849
850	for ( seg2 = segments; seg2 < segment_limit; seg2++ )
851	if ( seg1->dir + seg2->dir == 0 && seg2->pos > seg1->pos )
852	{
853	FT_Pos pos1 = seg1->pos;
854	FT_Pos pos2 = seg2->pos;
855	FT_Pos dist = pos2 - pos1;
856
857
858	if ( dist < 0 )
859	dist = -dist;
860
861	{
862	FT_Pos min = seg1->min_coord;
863	FT_Pos max = seg1->max_coord;
864	FT_Pos len, score;
865
866
867	if ( min < seg2->min_coord )
868	min = seg2->min_coord;
869
870	if ( max > seg2->max_coord )
871	max = seg2->max_coord;
872
873	len = max - min;
874	if ( len >= len_threshold )
875	{
876	score = dist + len_score / len;
877
878	if ( score < seg1->score )
879	{
880	seg1->score = score;
881	seg1->link = seg2;
882	}
883
884	if ( score < seg2->score )
885	{
886	seg2->score = score;
887	seg2->link = seg1;
888	}
889	}
890	}
891	}
892	}
893
894	/* now, compute the `serif' segments */
895	for ( seg1 = segments; seg1 < segment_limit; seg1++ )
896	{
897	seg2 = seg1->link;
898
899	if ( seg2 )
900	{
901	if ( seg2->link != seg1 )
902	{
903	seg1->link = 0;
904	seg1->serif = seg2->link;
905	}
906	}
907	}
908	}
909
910
911	FT_LOCAL_DEF( FT_Error )
912	af_latin_hints_compute_edges( AF_GlyphHints hints,
913	AF_Dimension dim )
914	{
915	AF_AxisHints axis = &hints->axis[dim];
916	FT_Error error = AF_Err_Ok;
917	FT_Memory memory = hints->memory;
918	AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim];
919
920	AF_Segment segments = axis->segments;
921	AF_Segment segment_limit = segments + axis->num_segments;
922	AF_Segment seg;
923
924	AF_Direction up_dir;
925	FT_Fixed scale;
926	FT_Pos edge_distance_threshold;
927	FT_Pos segment_length_threshold;
928
929
930	axis->num_edges = 0;
931
932	scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale
933	: hints->y_scale;
934
935	up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP
936	: AF_DIR_RIGHT;
937
938	/*
939	* We ignore all segments that are less than 1 pixels in length,
940	* to avoid many problems with serif fonts. We compute the
941	* corresponding threshold in font units.
942	*/
943	if ( dim == AF_DIMENSION_HORZ )
944	segment_length_threshold = FT_DivFix( 64, hints->y_scale );
945	else
946	segment_length_threshold = 0;
947
948	/*********************************************************************/
949	/* */
950	/* We will begin by generating a sorted table of edges for the */
951	/* current direction. To do so, we simply scan each segment and try */
952	/* to find an edge in our table that corresponds to its position. */
953	/* */
954	/* If no edge is found, we create and insert a new edge in the */
955	/* sorted table. Otherwise, we simply add the segment to the edge's */
956	/* list which will be processed in the second step to compute the */
957	/* edge's properties. */
958	/* */
959	/* Note that the edges table is sorted along the segment/edge */
960	/* position. */
961	/* */
962	/*********************************************************************/
963
964	edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold,
965	scale );
966	if ( edge_distance_threshold > 64 / 4 )
967	edge_distance_threshold = 64 / 4;
968
969	edge_distance_threshold = FT_DivFix( edge_distance_threshold,
970	scale );
971
972	for ( seg = segments; seg < segment_limit; seg++ )
973	{
974	AF_Edge found = 0;
975	FT_Int ee;
976
977
978	if ( seg->height < segment_length_threshold )
979	continue;
980
981	/* A special case for serif edges: If they are smaller than */
982	/* 1.5 pixels we ignore them. */
983	if ( seg->serif &&
984	2 * seg->height < 3 * segment_length_threshold )
985	continue;
986
987	/* look for an edge corresponding to the segment */
988	for ( ee = 0; ee < axis->num_edges; ee++ )
989	{
990	AF_Edge edge = axis->edges + ee;
991	FT_Pos dist;
992
993
994	dist = seg->pos - edge->fpos;
995	if ( dist < 0 )
996	dist = -dist;
997
998	if ( dist < edge_distance_threshold && edge->dir == seg->dir )
999	{
1000	found = edge;
1001	break;
1002	}
1003	}
1004
1005	if ( !found )
1006	{
1007	AF_Edge edge;
1008
1009
1010	/* insert a new edge in the list and */
1011	/* sort according to the position */
1012	error = af_axis_hints_new_edge( axis, seg->pos,
1013	(AF_Direction)seg->dir,
1014	memory, &edge );
1015	if ( error )
1016	goto Exit;
1017
1018	/* add the segment to the new edge's list */
1019	FT_ZERO( edge );
1020
1021	edge->first = seg;
1022	edge->last = seg;
1023	edge->fpos = seg->pos;
1024	edge->dir = seg->dir;
1025	edge->opos = edge->pos = FT_MulFix( seg->pos, scale );
1026	seg->edge_next = seg;
1027	}
1028	else
1029	{
1030	/* if an edge was found, simply add the segment to the edge's */
1031	/* list */
1032	seg->edge_next = found->first;
1033	found->last->edge_next = seg;
1034	found->last = seg;
1035	}
1036	}
1037
1038
1039	/*********************************************************************/
1040	/* */
1041	/* Good, we will now compute each edge's properties according to */
1042	/* segments found on its position. Basically, these are: */
1043	/* */
1044	/* - edge's main direction */
1045	/* - stem edge, serif edge or both (which defaults to stem then) */
1046	/* - rounded edge, straight or both (which defaults to straight) */
1047	/* - link for edge */
1048	/* */
1049	/*********************************************************************/
1050
1051	/* first of all, set the `edge' field in each segment -- this is */
1052	/* required in order to compute edge links */
1053
1054	/*
1055	* Note that removing this loop and setting the `edge' field of each
1056	* segment directly in the code above slows down execution speed for
1057	* some reasons on platforms like the Sun.
1058	*/
1059	{
1060	AF_Edge edges = axis->edges;
1061	AF_Edge edge_limit = edges + axis->num_edges;
1062	AF_Edge edge;
1063
1064
1065	for ( edge = edges; edge < edge_limit; edge++ )
1066	{
1067	seg = edge->first;
1068	if ( seg )
1069	do
1070	{
1071	seg->edge = edge;
1072	seg = seg->edge_next;
1073
1074	} while ( seg != edge->first );
1075	}
1076
1077	/* now, compute each edge properties */
1078	for ( edge = edges; edge < edge_limit; edge++ )
1079	{
1080	FT_Int is_round = 0; /* does it contain round segments? */
1081	FT_Int is_straight = 0; /* does it contain straight segments? */
1082	FT_Pos ups = 0; /* number of upwards segments */
1083	FT_Pos downs = 0; /* number of downwards segments */
1084
1085
1086	seg = edge->first;
1087
1088	do
1089	{
1090	FT_Bool is_serif;
1091
1092
1093	/* check for roundness of segment */
1094	if ( seg->flags & AF_EDGE_ROUND )
1095	is_round++;
1096	else
1097	is_straight++;
1098
1099	/* check for segment direction */
1100	if ( seg->dir == up_dir )
1101	ups += seg->max_coord-seg->min_coord;
1102	else
1103	downs += seg->max_coord-seg->min_coord;
1104
1105	/* check for links -- if seg->serif is set, then seg->link must */
1106	/* be ignored */
1107	is_serif = (FT_Bool)( seg->serif &&
1108	seg->serif->edge &&
1109	seg->serif->edge != edge );
1110
1111	if ( ( seg->link && seg->link->edge != NULL ) \|\| is_serif )
1112	{
1113	AF_Edge edge2;
1114	AF_Segment seg2;
1115
1116
1117	edge2 = edge->link;
1118	seg2 = seg->link;
1119
1120	if ( is_serif )
1121	{
1122	seg2 = seg->serif;
1123	edge2 = edge->serif;
1124	}
1125
1126	if ( edge2 )
1127	{
1128	FT_Pos edge_delta;
1129	FT_Pos seg_delta;
1130
1131
1132	edge_delta = edge->fpos - edge2->fpos;
1133	if ( edge_delta < 0 )
1134	edge_delta = -edge_delta;
1135
1136	seg_delta = seg->pos - seg2->pos;
1137	if ( seg_delta < 0 )
1138	seg_delta = -seg_delta;
1139
1140	if ( seg_delta < edge_delta )
1141	edge2 = seg2->edge;
1142	}
1143	else
1144	edge2 = seg2->edge;
1145
1146	if ( is_serif )
1147	{
1148	edge->serif = edge2;
1149	edge2->flags \|= AF_EDGE_SERIF;
1150	}
1151	else
1152	edge->link = edge2;
1153	}
1154
1155	seg = seg->edge_next;
1156
1157	} while ( seg != edge->first );
1158
1159	/* set the round/straight flags */
1160	edge->flags = AF_EDGE_NORMAL;
1161
1162	if ( is_round > 0 && is_round >= is_straight )
1163	edge->flags \|= AF_EDGE_ROUND;
1164
1165	#if 0
1166	/* set the edge's main direction */
1167	edge->dir = AF_DIR_NONE;
1168
1169	if ( ups > downs )
1170	edge->dir = (FT_Char)up_dir;
1171
1172	else if ( ups < downs )
1173	edge->dir = (FT_Char)-up_dir;
1174
1175	else if ( ups == downs )
1176	edge->dir = 0; /* both up and down! */
1177	#endif
1178
1179	/* gets rid of serifs if link is set */
1180	/* XXX: This gets rid of many unpleasant artefacts! */
1181	/* Example: the `c' in cour.pfa at size 13 */
1182
1183	if ( edge->serif && edge->link )
1184	edge->serif = 0;
1185	}
1186	}
1187
1188	Exit:
1189	return error;
1190	}
1191
1192
1193	FT_LOCAL_DEF( FT_Error )
1194	af_latin_hints_detect_features( AF_GlyphHints hints,
1195	AF_Dimension dim )
1196	{
1197	FT_Error error;
1198
1199
1200	error = af_latin_hints_compute_segments( hints, dim );
1201	if ( !error )
1202	{
1203	af_latin_hints_link_segments( hints, dim );
1204
1205	error = af_latin_hints_compute_edges( hints, dim );
1206	}
1207	return error;
1208	}
1209
1210
1211	FT_LOCAL_DEF( void )
1212	af_latin_hints_compute_blue_edges( AF_GlyphHints hints,
1213	AF_LatinMetrics metrics )
1214	{
1215	AF_AxisHints axis = &hints->axis[ AF_DIMENSION_VERT ];
1216	AF_Edge edge = axis->edges;
1217	AF_Edge edge_limit = edge + axis->num_edges;
1218	AF_LatinAxis latin = &metrics->axis[ AF_DIMENSION_VERT ];
1219	FT_Fixed scale = latin->scale;
1220
1221
1222	/* compute which blue zones are active, i.e. have their scaled */
1223	/* size < 3/4 pixels */
1224
1225	/* for each horizontal edge search the blue zone which is closest */
1226	for ( ; edge < edge_limit; edge++ )
1227	{
1228	FT_Int bb;
1229	AF_Width best_blue = NULL;
1230	FT_Pos best_dist; /* initial threshold */
1231
1232
1233	/* compute the initial threshold as a fraction of the EM size */
1234	best_dist = FT_MulFix( metrics->units_per_em / 40, scale );
1235
1236	if ( best_dist > 64 / 2 )
1237	best_dist = 64 / 2;
1238
1239	for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ )
1240	{
1241	AF_LatinBlue blue = latin->blues + bb;
1242	FT_Bool is_top_blue, is_major_dir;
1243
1244
1245	/* skip inactive blue zones (i.e., those that are too small) */
1246	if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) )
1247	continue;
1248
1249	/* if it is a top zone, check for right edges -- if it is a bottom */
1250	/* zone, check for left edges */
1251	/* */
1252	/* of course, that's for TrueType */
1253	is_top_blue = (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_TOP ) != 0 );
1254	is_major_dir = FT_BOOL( edge->dir == axis->major_dir );
1255
1256	/* if it is a top zone, the edge must be against the major */
1257	/* direction; if it is a bottom zone, it must be in the major */
1258	/* direction */
1259	if ( is_top_blue ^ is_major_dir )
1260	{
1261	FT_Pos dist;
1262
1263
1264	/* first of all, compare it to the reference position */
1265	dist = edge->fpos - blue->ref.org;
1266	if ( dist < 0 )
1267	dist = -dist;
1268
1269	dist = FT_MulFix( dist, scale );
1270	if ( dist < best_dist )
1271	{
1272	best_dist = dist;
1273	best_blue = & blue->ref;
1274	}
1275
1276	/* now, compare it to the overshoot position if the edge is */
1277	/* rounded, and if the edge is over the reference position of a */
1278	/* top zone, or under the reference position of a bottom zone */
1279	if ( edge->flags & AF_EDGE_ROUND && dist != 0 )
1280	{
1281	FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org );
1282
1283
1284	if ( is_top_blue ^ is_under_ref )
1285	{
1286	blue = latin->blues + bb;
1287	dist = edge->fpos - blue->shoot.org;
1288	if ( dist < 0 )
1289	dist = -dist;
1290
1291	dist = FT_MulFix( dist, scale );
1292	if ( dist < best_dist )
1293	{
1294	best_dist = dist;
1295	best_blue = & blue->shoot;
1296	}
1297	}
1298	}
1299	}
1300	}
1301
1302	if ( best_blue )
1303	edge->blue_edge = best_blue;
1304	}
1305	}
1306
1307
1308	static FT_Error
1309	af_latin_hints_init( AF_GlyphHints hints,
1310	AF_LatinMetrics metrics )
1311	{
1312	FT_Render_Mode mode;
1313	FT_UInt32 scaler_flags, other_flags;
1314	FT_Face face = metrics->root.scaler.face;
1315
1316
1317	af_glyph_hints_rescale( hints, (AF_ScriptMetrics)metrics );
1318
1319	/*
1320	* correct x_scale and y_scale if needed, since they may have
1321	* been modified `af_latin_metrics_scale_dim' above
1322	*/
1323	hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale;
1324	hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta;
1325	hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale;
1326	hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta;
1327
1328	/* compute flags depending on render mode, etc. */
1329	mode = metrics->root.scaler.render_mode;
1330
1331	#if 0 /* #ifdef AF_USE_WARPER */
1332	if ( mode == FT_RENDER_MODE_LCD \|\| mode == FT_RENDER_MODE_LCD_V )
1333	{
1334	metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL;
1335	}
1336	#endif
1337
1338	scaler_flags = hints->scaler_flags;
1339	other_flags = 0;
1340
1341	/*
1342	* We snap the width of vertical stems for the monochrome and
1343	* horizontal LCD rendering targets only.
1344	*/
1345	if ( mode == FT_RENDER_MODE_MONO \|\| mode == FT_RENDER_MODE_LCD )
1346	other_flags \|= AF_LATIN_HINTS_HORZ_SNAP;
1347
1348	/*
1349	* We snap the width of horizontal stems for the monochrome and
1350	* vertical LCD rendering targets only.
1351	*/
1352	if ( mode == FT_RENDER_MODE_MONO \|\| mode == FT_RENDER_MODE_LCD_V )
1353	other_flags \|= AF_LATIN_HINTS_VERT_SNAP;
1354
1355	/*
1356	* We adjust stems to full pixels only if we don't use the `light' mode.
1357	*/
1358	if ( mode != FT_RENDER_MODE_LIGHT )
1359	other_flags \|= AF_LATIN_HINTS_STEM_ADJUST;
1360
1361	if ( mode == FT_RENDER_MODE_MONO )
1362	other_flags \|= AF_LATIN_HINTS_MONO;
1363
1364	/*
1365	* In `light' hinting mode we disable horizontal hinting completely.
1366	* We also do it if the face is italic.
1367	*/
1368	if ( mode == FT_RENDER_MODE_LIGHT \|\|
1369	(face->style_flags & FT_STYLE_FLAG_ITALIC) != 0 )
1370	scaler_flags \|= AF_SCALER_FLAG_NO_HORIZONTAL;
1371
1372	hints->scaler_flags = scaler_flags;
1373	hints->other_flags = other_flags;
1374
1375	return 0;
1376	}
1377
1378
1379	/*************************************************************************/
1380	/*************************************************************************/
1381	/*** ***/
1382	/*** L A T I N G L Y P H G R I D - F I T T I N G ***/
1383	/*** ***/
1384	/*************************************************************************/
1385	/*************************************************************************/
1386
1387	/* snap a given width in scaled coordinates to one of the */
1388	/* current standard widths */
1389
1390	static FT_Pos
1391	af_latin_snap_width( AF_Width widths,
1392	FT_Int count,
1393	FT_Pos width )
1394	{
1395	int n;
1396	FT_Pos best = 64 + 32 + 2;
1397	FT_Pos reference = width;
1398	FT_Pos scaled;
1399
1400
1401	for ( n = 0; n < count; n++ )
1402	{
1403	FT_Pos w;
1404	FT_Pos dist;
1405
1406
1407	w = widths[n].cur;
1408	dist = width - w;
1409	if ( dist < 0 )
1410	dist = -dist;
1411	if ( dist < best )
1412	{
1413	best = dist;
1414	reference = w;
1415	}
1416	}
1417
1418	scaled = FT_PIX_ROUND( reference );
1419
1420	if ( width >= reference )
1421	{
1422	if ( width < scaled + 48 )
1423	width = reference;
1424	}
1425	else
1426	{
1427	if ( width > scaled - 48 )
1428	width = reference;
1429	}
1430
1431	return width;
1432	}
1433
1434
1435	/* compute the snapped width of a given stem */
1436
1437	static FT_Pos
1438	af_latin_compute_stem_width( AF_GlyphHints hints,
1439	AF_Dimension dim,
1440	FT_Pos width,
1441	AF_Edge_Flags base_flags,
1442	AF_Edge_Flags stem_flags )
1443	{
1444	AF_LatinMetrics metrics = (AF_LatinMetrics) hints->metrics;
1445	AF_LatinAxis axis = & metrics->axis[dim];
1446	FT_Pos dist = width;
1447	FT_Int sign = 0;
1448	FT_Int vertical = ( dim == AF_DIMENSION_VERT );
1449
1450
1451	if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) \|\|
1452	axis->extra_light )
1453	return width;
1454
1455	if ( dist < 0 )
1456	{
1457	dist = -width;
1458	sign = 1;
1459	}
1460
1461	if ( ( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) \|\|
1462	( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) )
1463	{
1464	/* smooth hinting process: very lightly quantize the stem width */
1465
1466	/* leave the widths of serifs alone */
1467
1468	if ( ( stem_flags & AF_EDGE_SERIF ) && vertical && ( dist < 3 * 64 ) )
1469	goto Done_Width;
1470
1471	else if ( ( base_flags & AF_EDGE_ROUND ) )
1472	{
1473	if ( dist < 80 )
1474	dist = 64;
1475	}
1476	else if ( dist < 56 )
1477	dist = 56;
1478
1479	if ( axis->width_count > 0 )
1480	{
1481	FT_Pos delta;
1482
1483
1484	/* compare to standard width */
1485	if ( axis->width_count > 0 )
1486	{
1487	delta = dist - axis->widths[0].cur;
1488
1489	if ( delta < 0 )
1490	delta = -delta;
1491
1492	if ( delta < 40 )
1493	{
1494	dist = axis->widths[0].cur;
1495	if ( dist < 48 )
1496	dist = 48;
1497
1498	goto Done_Width;
1499	}
1500	}
1501
1502	if ( dist < 3 * 64 )
1503	{
1504	delta = dist & 63;
1505	dist &= -64;
1506
1507	if ( delta < 10 )
1508	dist += delta;
1509
1510	else if ( delta < 32 )
1511	dist += 10;
1512
1513	else if ( delta < 54 )
1514	dist += 54;
1515
1516	else
1517	dist += delta;
1518	}
1519	else
1520	dist = ( dist + 32 ) & ~63;
1521	}
1522	}
1523	else
1524	{
1525	/* strong hinting process: snap the stem width to integer pixels */
1526	FT_Pos org_dist = dist;
1527
1528
1529	dist = af_latin_snap_width( axis->widths, axis->width_count, dist );
1530
1531	if ( vertical )
1532	{
1533	/* in the case of vertical hinting, always round */
1534	/* the stem heights to integer pixels */
1535
1536	if ( dist >= 64 )
1537	dist = ( dist + 16 ) & ~63;
1538	else
1539	dist = 64;
1540	}
1541	else
1542	{
1543	if ( AF_LATIN_HINTS_DO_MONO( hints ) )
1544	{
1545	/* monochrome horizontal hinting: snap widths to integer pixels */
1546	/* with a different threshold */
1547
1548	if ( dist < 64 )
1549	dist = 64;
1550	else
1551	dist = ( dist + 32 ) & ~63;
1552	}
1553	else
1554	{
1555	/* for horizontal anti-aliased hinting, we adopt a more subtle */
1556	/* approach: we strengthen small stems, round stems whose size */
1557	/* is between 1 and 2 pixels to an integer, otherwise nothing */
1558
1559	if ( dist < 48 )
1560	dist = ( dist + 64 ) >> 1;
1561
1562	else if ( dist < 128 )
1563	{
1564	/* We only round to an integer width if the corresponding */
1565	/* distortion is less than 1/4 pixel. Otherwise this */
1566	/* makes everything worse since the diagonals, which are */
1567	/* not hinted, appear a lot bolder or thinner than the */
1568	/* vertical stems. */
1569
1570	FT_Int delta;
1571
1572
1573	dist = ( dist + 22 ) & ~63;
1574	delta = dist - org_dist;
1575	if ( delta < 0 )
1576	delta = -delta;
1577
1578	if (delta >= 16)
1579	{
1580	dist = org_dist;
1581	if ( dist < 48 )
1582	dist = ( dist + 64 ) >> 1;
1583	}
1584	}
1585	else
1586	/* round otherwise to prevent color fringes in LCD mode */
1587	dist = ( dist + 32 ) & ~63;
1588	}
1589	}
1590	}
1591
1592	Done_Width:
1593	if ( sign )
1594	dist = -dist;
1595
1596	return dist;
1597	}
1598
1599
1600	/* align one stem edge relative to the previous stem edge */
1601
1602	static void
1603	af_latin_align_linked_edge( AF_GlyphHints hints,
1604	AF_Dimension dim,
1605	AF_Edge base_edge,
1606	AF_Edge stem_edge )
1607	{
1608	FT_Pos dist = stem_edge->opos - base_edge->opos;
1609
1610	FT_Pos fitted_width = af_latin_compute_stem_width(
1611	hints, dim, dist,
1612	(AF_Edge_Flags)base_edge->flags,
1613	(AF_Edge_Flags)stem_edge->flags );
1614
1615
1616	stem_edge->pos = base_edge->pos + fitted_width;
1617
1618	AF_LOG(( "LINK: edge %d (opos=%.2f) linked to (%.2f), "
1619	"dist was %.2f, now %.2f\n",
1620	stem_edge-hints->axis[dim].edges, stem_edge->opos / 64.0,
1621	stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 ));
1622	}
1623
1624
1625	static void
1626	af_latin_align_serif_edge( AF_GlyphHints hints,
1627	AF_Edge base,
1628	AF_Edge serif )
1629	{
1630	FT_UNUSED( hints );
1631
1632	serif->pos = base->pos + (serif->opos - base->opos);
1633	}
1634
1635
1636	/*************************************************************************/
1637	/*************************************************************************/
1638	/*************************************************************************/
1639	/** **/
1640	/** E D G E H I N T I N G **/
1641	/** **/
1642	/*************************************************************************/
1643	/*************************************************************************/
1644	/*************************************************************************/
1645
1646
1647	FT_LOCAL_DEF( void )
1648	af_latin_hint_edges( AF_GlyphHints hints,
1649	AF_Dimension dim )
1650	{
1651	AF_AxisHints axis = &hints->axis[dim];
1652	AF_Edge edges = axis->edges;
1653	AF_Edge edge_limit = edges + axis->num_edges;
1654	FT_Int n_edges;
1655	AF_Edge edge;
1656	AF_Edge anchor = 0;
1657	FT_Int has_serifs = 0;
1658
1659
1660	/* we begin by aligning all stems relative to the blue zone */
1661	/* if needed -- that's only for horizontal edges */
1662
1663	if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) )
1664	{
1665	for ( edge = edges; edge < edge_limit; edge++ )
1666	{
1667	AF_Width blue;
1668	AF_Edge edge1, edge2;
1669
1670
1671	if ( edge->flags & AF_EDGE_DONE )
1672	continue;
1673
1674	blue = edge->blue_edge;
1675	edge1 = NULL;
1676	edge2 = edge->link;
1677
1678	if ( blue )
1679	{
1680	edge1 = edge;
1681	}
1682	else if ( edge2 && edge2->blue_edge )
1683	{
1684	blue = edge2->blue_edge;
1685	edge1 = edge2;
1686	edge2 = edge;
1687	}
1688
1689	if ( !edge1 )
1690	continue;
1691
1692	AF_LOG(( "BLUE: edge %d (opos=%.2f) snapped to (%.2f), "
1693	"was (%.2f)\n",
1694	edge1-edges, edge1->opos / 64.0, blue->fit / 64.0,
1695	edge1->pos / 64.0 ));
1696
1697	edge1->pos = blue->fit;
1698	edge1->flags \|= AF_EDGE_DONE;
1699
1700	if ( edge2 && !edge2->blue_edge )
1701	{
1702	af_latin_align_linked_edge( hints, dim, edge1, edge2 );
1703	edge2->flags \|= AF_EDGE_DONE;
1704	}
1705
1706	if ( !anchor )
1707	anchor = edge;
1708	}
1709	}
1710
1711	/* now we will align all stem edges, trying to maintain the */
1712	/* relative order of stems in the glyph */
1713	for ( edge = edges; edge < edge_limit; edge++ )
1714	{
1715	AF_Edge edge2;
1716
1717
1718	if ( edge->flags & AF_EDGE_DONE )
1719	continue;
1720
1721	/* skip all non-stem edges */
1722	edge2 = edge->link;
1723	if ( !edge2 )
1724	{
1725	has_serifs++;
1726	continue;
1727	}
1728
1729	/* now align the stem */
1730
1731	/* this should not happen, but it's better to be safe */
1732	if ( edge2->blue_edge )
1733	{
1734	AF_LOG(( "ASSERTION FAILED for edge %d\n", edge2-edges ));
1735
1736	af_latin_align_linked_edge( hints, dim, edge2, edge );
1737	edge->flags \|= AF_EDGE_DONE;
1738	continue;
1739	}
1740
1741	if ( !anchor )
1742	{
1743	FT_Pos org_len, org_center, cur_len;
1744	FT_Pos cur_pos1, error1, error2, u_off, d_off;
1745
1746
1747	org_len = edge2->opos - edge->opos;
1748	cur_len = af_latin_compute_stem_width(
1749	hints, dim, org_len,
1750	(AF_Edge_Flags)edge->flags,
1751	(AF_Edge_Flags)edge2->flags );
1752	if ( cur_len <= 64 )
1753	u_off = d_off = 32;
1754	else
1755	{
1756	u_off = 38;
1757	d_off = 26;
1758	}
1759
1760	if ( cur_len < 96 )
1761	{
1762	org_center = edge->opos + ( org_len >> 1 );
1763
1764	cur_pos1 = FT_PIX_ROUND( org_center );
1765
1766	error1 = org_center - ( cur_pos1 - u_off );
1767	if ( error1 < 0 )
1768	error1 = -error1;
1769
1770	error2 = org_center - ( cur_pos1 + d_off );
1771	if ( error2 < 0 )
1772	error2 = -error2;
1773
1774	if ( error1 < error2 )
1775	cur_pos1 -= u_off;
1776	else
1777	cur_pos1 += d_off;
1778
1779	edge->pos = cur_pos1 - cur_len / 2;
1780	edge2->pos = edge->pos + cur_len;
1781	}
1782	else
1783	edge->pos = FT_PIX_ROUND( edge->opos );
1784
1785	AF_LOG(( "ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f) "
1786	"snapped to (%.2f) (%.2f)\n",
1787	edge-edges, edge->opos / 64.0,
1788	edge2-edges, edge2->opos / 64.0,
1789	edge->pos / 64.0, edge2->pos / 64.0 ));
1790	anchor = edge;
1791
1792	edge->flags \|= AF_EDGE_DONE;
1793
1794	af_latin_align_linked_edge( hints, dim, edge, edge2 );
1795	}
1796	else
1797	{
1798	FT_Pos org_pos, org_len, org_center, cur_len;
1799	FT_Pos cur_pos1, cur_pos2, delta1, delta2;
1800
1801
1802	org_pos = anchor->pos + ( edge->opos - anchor->opos );
1803	org_len = edge2->opos - edge->opos;
1804	org_center = org_pos + ( org_len >> 1 );
1805
1806	cur_len = af_latin_compute_stem_width(
1807	hints, dim, org_len,
1808	(AF_Edge_Flags)edge->flags,
1809	(AF_Edge_Flags)edge2->flags );
1810
1811	if ( edge2->flags & AF_EDGE_DONE )
1812	edge->pos = edge2->pos - cur_len;
1813
1814	else if ( cur_len < 96 )
1815	{
1816	FT_Pos u_off, d_off;
1817
1818
1819	cur_pos1 = FT_PIX_ROUND( org_center );
1820
1821	if (cur_len <= 64 )
1822	u_off = d_off = 32;
1823	else
1824	{
1825	u_off = 38;
1826	d_off = 26;
1827	}
1828
1829	delta1 = org_center - ( cur_pos1 - u_off );
1830	if ( delta1 < 0 )
1831	delta1 = -delta1;
1832
1833	delta2 = org_center - ( cur_pos1 + d_off );
1834	if ( delta2 < 0 )
1835	delta2 = -delta2;
1836
1837	if ( delta1 < delta2 )
1838	cur_pos1 -= u_off;
1839	else
1840	cur_pos1 += d_off;
1841
1842	edge->pos = cur_pos1 - cur_len / 2;
1843	edge2->pos = cur_pos1 + cur_len / 2;
1844
1845	AF_LOG(( "STEM: %d (opos=%.2f) to %d (opos=%.2f) "
1846	"snapped to (%.2f) and (%.2f)\n",
1847	edge-edges, edge->opos / 64.0,
1848	edge2-edges, edge2->opos / 64.0,
1849	edge->pos / 64.0, edge2->pos / 64.0 ));
1850	}
1851	else
1852	{
1853	org_pos = anchor->pos + ( edge->opos - anchor->opos );
1854	org_len = edge2->opos - edge->opos;
1855	org_center = org_pos + ( org_len >> 1 );
1856
1857	cur_len = af_latin_compute_stem_width(
1858	hints, dim, org_len,
1859	(AF_Edge_Flags)edge->flags,
1860	(AF_Edge_Flags)edge2->flags );
1861
1862	cur_pos1 = FT_PIX_ROUND( org_pos );
1863	delta1 = cur_pos1 + ( cur_len >> 1 ) - org_center;
1864	if ( delta1 < 0 )
1865	delta1 = -delta1;
1866
1867	cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len;
1868	delta2 = cur_pos2 + ( cur_len >> 1 ) - org_center;
1869	if ( delta2 < 0 )
1870	delta2 = -delta2;
1871
1872	edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2;
1873	edge2->pos = edge->pos + cur_len;
1874
1875	AF_LOG(( "STEM: %d (opos=%.2f) to %d (opos=%.2f) "
1876	"snapped to (%.2f) and (%.2f)\n",
1877	edge-edges, edge->opos / 64.0,
1878	edge2-edges, edge2->opos / 64.0,
1879	edge->pos / 64.0, edge2->pos / 64.0 ));
1880	}
1881
1882	edge->flags \|= AF_EDGE_DONE;
1883	edge2->flags \|= AF_EDGE_DONE;
1884
1885	if ( edge > edges && edge->pos < edge[-1].pos )
1886	{
1887	AF_LOG(( "BOUND: %d (pos=%.2f) to (%.2f)\n",
1888	edge-edges, edge->pos / 64.0, edge[-1].pos / 64.0 ));
1889	edge->pos = edge[-1].pos;
1890	}
1891	}
1892	}
1893
1894	/* make sure that lowercase m's maintain their symmetry */
1895
1896	/* In general, lowercase m's have six vertical edges if they are sans */
1897	/* serif, or twelve if they are with serifs. This implementation is */
1898	/* based on that assumption, and seems to work very well with most */
1899	/* faces. However, if for a certain face this assumption is not */
1900	/* true, the m is just rendered like before. In addition, any stem */
1901	/* correction will only be applied to symmetrical glyphs (even if the */
1902	/* glyph is not an m), so the potential for unwanted distortion is */
1903	/* relatively low. */
1904
1905	/* We don't handle horizontal edges since we can't easily assure that */
1906	/* the third (lowest) stem aligns with the base line; it might end up */
1907	/* one pixel higher or lower. */
1908
1909	n_edges = edge_limit - edges;
1910	if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 \|\| n_edges == 12 ) )
1911	{
1912	AF_Edge edge1, edge2, edge3;
1913	FT_Pos dist1, dist2, span, delta;
1914
1915
1916	if ( n_edges == 6 )
1917	{
1918	edge1 = edges;
1919	edge2 = edges + 2;
1920	edge3 = edges + 4;
1921	}
1922	else
1923	{
1924	edge1 = edges + 1;
1925	edge2 = edges + 5;
1926	edge3 = edges + 9;
1927	}
1928
1929	dist1 = edge2->opos - edge1->opos;
1930	dist2 = edge3->opos - edge2->opos;
1931
1932	span = dist1 - dist2;
1933	if ( span < 0 )
1934	span = -span;
1935
1936	if ( span < 8 )
1937	{
1938	delta = edge3->pos - ( 2 * edge2->pos - edge1->pos );
1939	edge3->pos -= delta;
1940	if ( edge3->link )
1941	edge3->link->pos -= delta;
1942
1943	/* move the serifs along with the stem */
1944	if ( n_edges == 12 )
1945	{
1946	( edges + 8 )->pos -= delta;
1947	( edges + 11 )->pos -= delta;
1948	}
1949
1950	edge3->flags \|= AF_EDGE_DONE;
1951	if ( edge3->link )
1952	edge3->link->flags \|= AF_EDGE_DONE;
1953	}
1954	}
1955
1956	if ( has_serifs \|\| !anchor )
1957	{
1958	/*
1959	* now hint the remaining edges (serifs and single) in order
1960	* to complete our processing
1961	*/
1962	for ( edge = edges; edge < edge_limit; edge++ )
1963	{
1964	FT_Pos delta;
1965
1966
1967	if ( edge->flags & AF_EDGE_DONE )
1968	continue;
1969
1970	delta = 1000;
1971
1972	if ( edge->serif )
1973	{
1974	delta = edge->serif->opos - edge->opos;
1975	if ( delta < 0 )
1976	delta = -delta;
1977	}
1978
1979	if ( delta < 64 + 16 )
1980	{
1981	af_latin_align_serif_edge( hints, edge->serif, edge );
1982	AF_LOG(( "SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f) "
1983	"aligned to (%.2f)\n",
1984	edge-edges, edge->opos / 64.0,
1985	edge->serif - edges, edge->serif->opos / 64.0,
1986	edge->pos / 64.0 ));
1987	}
1988	else if ( !anchor )
1989	{
1990	AF_LOG(( "SERIF_ANCHOR: edge %d (opos=%.2f) snapped to (%.2f)\n",
1991	edge-edges, edge->opos / 64.0, edge->pos / 64.0 ));
1992	edge->pos = FT_PIX_ROUND( edge->opos );
1993	anchor = edge;
1994	}
1995	else
1996	{
1997	AF_Edge before, after;
1998
1999
2000	for ( before = edge - 1; before >= edges; before-- )
2001	if ( before->flags & AF_EDGE_DONE )
2002	break;
2003
2004	for ( after = edge + 1; after < edge_limit; after++ )
2005	if ( after->flags & AF_EDGE_DONE )
2006	break;
2007
2008	if ( before >= edges && before < edge &&
2009	after < edge_limit && after > edge )
2010	{
2011	edge->pos = before->pos +
2012	FT_MulDiv( edge->opos - before->opos,
2013	after->pos - before->pos,
2014	after->opos - before->opos );
2015	AF_LOG(( "SERIF_LINK1: edge %d (opos=%.2f) snapped to (%.2f) "
2016	"from %d (opos=%.2f)\n",
2017	edge-edges, edge->opos / 64.0,
2018	edge->pos / 64.0, before - edges,
2019	before->opos / 64.0 ));
2020	}
2021	else
2022	{
2023	edge->pos = anchor->pos +
2024	( ( edge->opos - anchor->opos + 16 ) & ~31 );
2025	AF_LOG(( "SERIF_LINK2: edge %d (opos=%.2f) snapped to (%.2f)\n",
2026	edge-edges, edge->opos / 64.0, edge->pos / 64.0 ));
2027	}
2028	}
2029
2030	edge->flags \|= AF_EDGE_DONE;
2031
2032	if ( edge > edges && edge->pos < edge[-1].pos )
2033	edge->pos = edge[-1].pos;
2034
2035	if ( edge + 1 < edge_limit &&
2036	edge[1].flags & AF_EDGE_DONE &&
2037	edge->pos > edge[1].pos )
2038	edge->pos = edge[1].pos;
2039	}
2040	}
2041	}
2042
2043
2044	static FT_Error
2045	af_latin_hints_apply( AF_GlyphHints hints,
2046	FT_Outline* outline,
2047	AF_LatinMetrics metrics )
2048	{
2049	FT_Error error;
2050	int dim;
2051
2052
2053	error = af_glyph_hints_reload( hints, outline, 1 );
2054	if ( error )
2055	goto Exit;
2056
2057	/* analyze glyph outline */
2058	#ifdef AF_USE_WARPER
2059	if ( metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT \|\|
2060	AF_HINTS_DO_HORIZONTAL( hints ) )
2061	#else
2062	if ( AF_HINTS_DO_HORIZONTAL( hints ) )
2063	#endif
2064	{
2065	error = af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ );
2066	if ( error )
2067	goto Exit;
2068	}
2069
2070	if ( AF_HINTS_DO_VERTICAL( hints ) )
2071	{
2072	error = af_latin_hints_detect_features( hints, AF_DIMENSION_VERT );
2073	if ( error )
2074	goto Exit;
2075
2076	af_latin_hints_compute_blue_edges( hints, metrics );
2077	}
2078
2079	/* grid-fit the outline */
2080	for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
2081	{
2082	#ifdef AF_USE_WARPER
2083	if ( ( dim == AF_DIMENSION_HORZ &&
2084	metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT ) )
2085	{
2086	AF_WarperRec warper;
2087	FT_Fixed scale;
2088	FT_Pos delta;
2089
2090
2091	af_warper_compute( &warper, hints, dim, &scale, &delta );
2092	af_glyph_hints_scale_dim( hints, dim, scale, delta );
2093	continue;
2094	}
2095	#endif
2096
2097	if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) \|\|
2098	( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) ) )
2099	{
2100	af_latin_hint_edges( hints, (AF_Dimension)dim );
2101	af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim );
2102	af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim );
2103	af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim );
2104	}
2105	}
2106	af_glyph_hints_save( hints, outline );
2107
2108	Exit:
2109	return error;
2110	}
2111
2112
2113	/*************************************************************************/
2114	/*************************************************************************/
2115	/*** ***/
2116	/*** L A T I N S C R I P T C L A S S ***/
2117	/*** ***/
2118	/*************************************************************************/
2119	/*************************************************************************/
2120
2121
2122	/* XXX: this should probably fine tuned to differentiate better between */
2123	/* scripts... */
2124
2125	static const AF_Script_UniRangeRec af_latin_uniranges[] =
2126	{
2127	{ 0x0020, 0x007F }, /* Basic Latin (no control characters) */
2128	{ 0x00A0, 0x00FF }, /* Latin-1 Supplement (no control characters) */
2129	{ 0x0100, 0x017F }, /* Latin Extended-A */
2130	{ 0x0180, 0x024F }, /* Latin Extended-B */
2131	{ 0x0250, 0x02AF }, /* IPA Extensions */
2132	{ 0x02B0, 0x02FF }, /* Spacing Modifier Letters */
2133	{ 0x0300, 0x036F }, /* Combining Diacritical Marks */
2134	{ 0x0370, 0x03FF }, /* Greek and Coptic */
2135	{ 0x0400, 0x04FF }, /* Cyrillic */
2136	{ 0x0500, 0x052F }, /* Cyrillic Supplement */
2137	{ 0x1D00, 0x1D7F }, /* Phonetic Extensions */
2138	{ 0x1D80, 0x1DBF }, /* Phonetic Extensions Supplement */
2139	{ 0x1DC0, 0x1DFF }, /* Combining Diacritical Marks Supplement */
2140	{ 0x1E00, 0x1EFF }, /* Latin Extended Additional */
2141	{ 0x1F00, 0x1FFF }, /* Greek Extended */
2142	{ 0x2000, 0x206F }, /* General Punctuation */
2143	{ 0x2070, 0x209F }, /* Superscripts and Subscripts */
2144	{ 0x20A0, 0x20CF }, /* Currency Symbols */
2145	{ 0x2150, 0x218F }, /* Number Forms */
2146	{ 0x2460, 0x24FF }, /* Enclosed Alphanumerics */
2147	{ 0 , 0 }
2148	};
2149
2150
2151	FT_CALLBACK_TABLE_DEF const AF_ScriptClassRec
2152	af_latin_script_class =
2153	{
2154	AF_SCRIPT_LATIN,
2155	af_latin_uniranges,
2156
2157	sizeof( AF_LatinMetricsRec ),
2158
2159	(AF_Script_InitMetricsFunc) af_latin_metrics_init,
2160	(AF_Script_ScaleMetricsFunc)af_latin_metrics_scale,
2161	(AF_Script_DoneMetricsFunc) NULL,
2162
2163	(AF_Script_InitHintsFunc) af_latin_hints_init,
2164	(AF_Script_ApplyHintsFunc) af_latin_hints_apply
2165	};
2166
2167
2168	/* END */

Note: See TracBrowser for help on using the repository browser.

Download in other formats: