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1 /***************************************************************************/
2 /*                                                                         */
3 /*  pshalgo.c                                                              */
4 /*                                                                         */
5 /*    PostScript hinting algorithm (body).                                 */
6 /*                                                                         */
7 /*  Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010   */
8 /*            by                                                           */
9 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
10 /*                                                                         */
11 /*  This file is part of the FreeType project, and may only be used        */
12 /*  modified and distributed under the terms of the FreeType project       */
13 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
14 /*  this file you indicate that you have read the license and              */
15 /*  understand and accept it fully.                                        */
16 /*                                                                         */
17 /***************************************************************************/
18 
19 
20 #include <ft2build.h>
21 #include FT_INTERNAL_OBJECTS_H
22 #include FT_INTERNAL_DEBUG_H
23 #include FT_INTERNAL_CALC_H
24 #include "pshalgo.h"
25 
26 #include "pshnterr.h"
27 
28 
29 #undef  FT_COMPONENT
30 #define FT_COMPONENT  trace_pshalgo2
31 
32 
33 #ifdef DEBUG_HINTER
34   PSH_Hint_Table  ps_debug_hint_table = 0;
35   PSH_HintFunc    ps_debug_hint_func  = 0;
36   PSH_Glyph       ps_debug_glyph      = 0;
37 #endif
38 
39 
40 #define  COMPUTE_INFLEXS  /* compute inflection points to optimize `S' */
41                           /* and similar glyphs                        */
42 #define  STRONGER         /* slightly increase the contrast of smooth  */
43                           /* hinting                                   */
44 
45 
46   /*************************************************************************/
47   /*************************************************************************/
48   /*****                                                               *****/
49   /*****                  BASIC HINTS RECORDINGS                       *****/
50   /*****                                                               *****/
51   /*************************************************************************/
52   /*************************************************************************/
53 
54   /* return true if two stem hints overlap */
55   static FT_Int
psh_hint_overlap(PSH_Hint hint1,PSH_Hint hint2)56   psh_hint_overlap( PSH_Hint  hint1,
57                     PSH_Hint  hint2 )
58   {
59     return hint1->org_pos + hint1->org_len >= hint2->org_pos &&
60            hint2->org_pos + hint2->org_len >= hint1->org_pos;
61   }
62 
63 
64   /* destroy hints table */
65   static void
psh_hint_table_done(PSH_Hint_Table table,FT_Memory memory)66   psh_hint_table_done( PSH_Hint_Table  table,
67                        FT_Memory       memory )
68   {
69     FT_FREE( table->zones );
70     table->num_zones = 0;
71     table->zone      = 0;
72 
73     FT_FREE( table->sort );
74     FT_FREE( table->hints );
75     table->num_hints   = 0;
76     table->max_hints   = 0;
77     table->sort_global = 0;
78   }
79 
80 
81   /* deactivate all hints in a table */
82   static void
psh_hint_table_deactivate(PSH_Hint_Table table)83   psh_hint_table_deactivate( PSH_Hint_Table  table )
84   {
85     FT_UInt   count = table->max_hints;
86     PSH_Hint  hint  = table->hints;
87 
88 
89     for ( ; count > 0; count--, hint++ )
90     {
91       psh_hint_deactivate( hint );
92       hint->order = -1;
93     }
94   }
95 
96 
97   /* internal function to record a new hint */
98   static void
psh_hint_table_record(PSH_Hint_Table table,FT_UInt idx)99   psh_hint_table_record( PSH_Hint_Table  table,
100                          FT_UInt         idx )
101   {
102     PSH_Hint  hint = table->hints + idx;
103 
104 
105     if ( idx >= table->max_hints )
106     {
107       FT_TRACE0(( "psh_hint_table_record: invalid hint index %d\n", idx ));
108       return;
109     }
110 
111     /* ignore active hints */
112     if ( psh_hint_is_active( hint ) )
113       return;
114 
115     psh_hint_activate( hint );
116 
117     /* now scan the current active hint set to check */
118     /* whether `hint' overlaps with another hint     */
119     {
120       PSH_Hint*  sorted = table->sort_global;
121       FT_UInt    count  = table->num_hints;
122       PSH_Hint   hint2;
123 
124 
125       hint->parent = 0;
126       for ( ; count > 0; count--, sorted++ )
127       {
128         hint2 = sorted[0];
129 
130         if ( psh_hint_overlap( hint, hint2 ) )
131         {
132           hint->parent = hint2;
133           break;
134         }
135       }
136     }
137 
138     if ( table->num_hints < table->max_hints )
139       table->sort_global[table->num_hints++] = hint;
140     else
141       FT_TRACE0(( "psh_hint_table_record: too many sorted hints!  BUG!\n" ));
142   }
143 
144 
145   static void
psh_hint_table_record_mask(PSH_Hint_Table table,PS_Mask hint_mask)146   psh_hint_table_record_mask( PSH_Hint_Table  table,
147                               PS_Mask         hint_mask )
148   {
149     FT_Int    mask = 0, val = 0;
150     FT_Byte*  cursor = hint_mask->bytes;
151     FT_UInt   idx, limit;
152 
153 
154     limit = hint_mask->num_bits;
155 
156     for ( idx = 0; idx < limit; idx++ )
157     {
158       if ( mask == 0 )
159       {
160         val  = *cursor++;
161         mask = 0x80;
162       }
163 
164       if ( val & mask )
165         psh_hint_table_record( table, idx );
166 
167       mask >>= 1;
168     }
169   }
170 
171 
172   /* create hints table */
173   static FT_Error
psh_hint_table_init(PSH_Hint_Table table,PS_Hint_Table hints,PS_Mask_Table hint_masks,PS_Mask_Table counter_masks,FT_Memory memory)174   psh_hint_table_init( PSH_Hint_Table  table,
175                        PS_Hint_Table   hints,
176                        PS_Mask_Table   hint_masks,
177                        PS_Mask_Table   counter_masks,
178                        FT_Memory       memory )
179   {
180     FT_UInt   count;
181     FT_Error  error;
182 
183     FT_UNUSED( counter_masks );
184 
185 
186     count = hints->num_hints;
187 
188     /* allocate our tables */
189     if ( FT_NEW_ARRAY( table->sort,  2 * count     ) ||
190          FT_NEW_ARRAY( table->hints,     count     ) ||
191          FT_NEW_ARRAY( table->zones, 2 * count + 1 ) )
192       goto Exit;
193 
194     table->max_hints   = count;
195     table->sort_global = table->sort + count;
196     table->num_hints   = 0;
197     table->num_zones   = 0;
198     table->zone        = 0;
199 
200     /* initialize the `table->hints' array */
201     {
202       PSH_Hint  write = table->hints;
203       PS_Hint   read  = hints->hints;
204 
205 
206       for ( ; count > 0; count--, write++, read++ )
207       {
208         write->org_pos = read->pos;
209         write->org_len = read->len;
210         write->flags   = read->flags;
211       }
212     }
213 
214     /* we now need to determine the initial `parent' stems; first  */
215     /* activate the hints that are given by the initial hint masks */
216     if ( hint_masks )
217     {
218       PS_Mask  mask = hint_masks->masks;
219 
220 
221       count             = hint_masks->num_masks;
222       table->hint_masks = hint_masks;
223 
224       for ( ; count > 0; count--, mask++ )
225         psh_hint_table_record_mask( table, mask );
226     }
227 
228     /* finally, do a linear parse in case some hints were left alone */
229     if ( table->num_hints != table->max_hints )
230     {
231       FT_UInt  idx;
232 
233 
234       FT_TRACE0(( "psh_hint_table_init: missing/incorrect hint masks\n" ));
235 
236       count = table->max_hints;
237       for ( idx = 0; idx < count; idx++ )
238         psh_hint_table_record( table, idx );
239     }
240 
241   Exit:
242     return error;
243   }
244 
245 
246   static void
psh_hint_table_activate_mask(PSH_Hint_Table table,PS_Mask hint_mask)247   psh_hint_table_activate_mask( PSH_Hint_Table  table,
248                                 PS_Mask         hint_mask )
249   {
250     FT_Int    mask = 0, val = 0;
251     FT_Byte*  cursor = hint_mask->bytes;
252     FT_UInt   idx, limit, count;
253 
254 
255     limit = hint_mask->num_bits;
256     count = 0;
257 
258     psh_hint_table_deactivate( table );
259 
260     for ( idx = 0; idx < limit; idx++ )
261     {
262       if ( mask == 0 )
263       {
264         val  = *cursor++;
265         mask = 0x80;
266       }
267 
268       if ( val & mask )
269       {
270         PSH_Hint  hint = &table->hints[idx];
271 
272 
273         if ( !psh_hint_is_active( hint ) )
274         {
275           FT_UInt     count2;
276 
277 #if 0
278           PSH_Hint*  sort = table->sort;
279           PSH_Hint   hint2;
280 
281 
282           for ( count2 = count; count2 > 0; count2--, sort++ )
283           {
284             hint2 = sort[0];
285             if ( psh_hint_overlap( hint, hint2 ) )
286               FT_TRACE0(( "psh_hint_table_activate_mask:"
287                           " found overlapping hints\n" ))
288           }
289 #else
290           count2 = 0;
291 #endif
292 
293           if ( count2 == 0 )
294           {
295             psh_hint_activate( hint );
296             if ( count < table->max_hints )
297               table->sort[count++] = hint;
298             else
299               FT_TRACE0(( "psh_hint_tableactivate_mask:"
300                           " too many active hints\n" ));
301           }
302         }
303       }
304 
305       mask >>= 1;
306     }
307     table->num_hints = count;
308 
309     /* now, sort the hints; they are guaranteed to not overlap */
310     /* so we can compare their "org_pos" field directly        */
311     {
312       FT_Int     i1, i2;
313       PSH_Hint   hint1, hint2;
314       PSH_Hint*  sort = table->sort;
315 
316 
317       /* a simple bubble sort will do, since in 99% of cases, the hints */
318       /* will be already sorted -- and the sort will be linear          */
319       for ( i1 = 1; i1 < (FT_Int)count; i1++ )
320       {
321         hint1 = sort[i1];
322         for ( i2 = i1 - 1; i2 >= 0; i2-- )
323         {
324           hint2 = sort[i2];
325 
326           if ( hint2->org_pos < hint1->org_pos )
327             break;
328 
329           sort[i2 + 1] = hint2;
330           sort[i2]     = hint1;
331         }
332       }
333     }
334   }
335 
336 
337   /*************************************************************************/
338   /*************************************************************************/
339   /*****                                                               *****/
340   /*****               HINTS GRID-FITTING AND OPTIMIZATION             *****/
341   /*****                                                               *****/
342   /*************************************************************************/
343   /*************************************************************************/
344 
345 #if 1
346   static FT_Pos
psh_dimension_quantize_len(PSH_Dimension dim,FT_Pos len,FT_Bool do_snapping)347   psh_dimension_quantize_len( PSH_Dimension  dim,
348                               FT_Pos         len,
349                               FT_Bool        do_snapping )
350   {
351     if ( len <= 64 )
352       len = 64;
353     else
354     {
355       FT_Pos  delta = len - dim->stdw.widths[0].cur;
356 
357 
358       if ( delta < 0 )
359         delta = -delta;
360 
361       if ( delta < 40 )
362       {
363         len = dim->stdw.widths[0].cur;
364         if ( len < 48 )
365           len = 48;
366       }
367 
368       if ( len < 3 * 64 )
369       {
370         delta = ( len & 63 );
371         len  &= -64;
372 
373         if ( delta < 10 )
374           len += delta;
375 
376         else if ( delta < 32 )
377           len += 10;
378 
379         else if ( delta < 54 )
380           len += 54;
381 
382         else
383           len += delta;
384       }
385       else
386         len = FT_PIX_ROUND( len );
387     }
388 
389     if ( do_snapping )
390       len = FT_PIX_ROUND( len );
391 
392     return  len;
393   }
394 #endif /* 0 */
395 
396 
397 #ifdef DEBUG_HINTER
398 
399   static void
ps_simple_scale(PSH_Hint_Table table,FT_Fixed scale,FT_Fixed delta,FT_Int dimension)400   ps_simple_scale( PSH_Hint_Table  table,
401                    FT_Fixed        scale,
402                    FT_Fixed        delta,
403                    FT_Int          dimension )
404   {
405     PSH_Hint  hint;
406     FT_UInt   count;
407 
408 
409     for ( count = 0; count < table->max_hints; count++ )
410     {
411       hint = table->hints + count;
412 
413       hint->cur_pos = FT_MulFix( hint->org_pos, scale ) + delta;
414       hint->cur_len = FT_MulFix( hint->org_len, scale );
415 
416       if ( ps_debug_hint_func )
417         ps_debug_hint_func( hint, dimension );
418     }
419   }
420 
421 #endif /* DEBUG_HINTER */
422 
423 
424   static FT_Fixed
psh_hint_snap_stem_side_delta(FT_Fixed pos,FT_Fixed len)425   psh_hint_snap_stem_side_delta( FT_Fixed  pos,
426                                  FT_Fixed  len )
427   {
428     FT_Fixed  delta1 = FT_PIX_ROUND( pos ) - pos;
429     FT_Fixed  delta2 = FT_PIX_ROUND( pos + len ) - pos - len;
430 
431 
432     if ( FT_ABS( delta1 ) <= FT_ABS( delta2 ) )
433       return delta1;
434     else
435       return delta2;
436   }
437 
438 
439   static void
psh_hint_align(PSH_Hint hint,PSH_Globals globals,FT_Int dimension,PSH_Glyph glyph)440   psh_hint_align( PSH_Hint     hint,
441                   PSH_Globals  globals,
442                   FT_Int       dimension,
443                   PSH_Glyph    glyph )
444   {
445     PSH_Dimension  dim   = &globals->dimension[dimension];
446     FT_Fixed       scale = dim->scale_mult;
447     FT_Fixed       delta = dim->scale_delta;
448 
449 
450     if ( !psh_hint_is_fitted( hint ) )
451     {
452       FT_Pos  pos = FT_MulFix( hint->org_pos, scale ) + delta;
453       FT_Pos  len = FT_MulFix( hint->org_len, scale );
454 
455       FT_Int            do_snapping;
456       FT_Pos            fit_len;
457       PSH_AlignmentRec  align;
458 
459 
460       /* ignore stem alignments when requested through the hint flags */
461       if ( ( dimension == 0 && !glyph->do_horz_hints ) ||
462            ( dimension == 1 && !glyph->do_vert_hints ) )
463       {
464         hint->cur_pos = pos;
465         hint->cur_len = len;
466 
467         psh_hint_set_fitted( hint );
468         return;
469       }
470 
471       /* perform stem snapping when requested - this is necessary
472        * for monochrome and LCD hinting modes only
473        */
474       do_snapping = ( dimension == 0 && glyph->do_horz_snapping ) ||
475                     ( dimension == 1 && glyph->do_vert_snapping );
476 
477       hint->cur_len = fit_len = len;
478 
479       /* check blue zones for horizontal stems */
480       align.align     = PSH_BLUE_ALIGN_NONE;
481       align.align_bot = align.align_top = 0;
482 
483       if ( dimension == 1 )
484         psh_blues_snap_stem( &globals->blues,
485                              hint->org_pos + hint->org_len,
486                              hint->org_pos,
487                              &align );
488 
489       switch ( align.align )
490       {
491       case PSH_BLUE_ALIGN_TOP:
492         /* the top of the stem is aligned against a blue zone */
493         hint->cur_pos = align.align_top - fit_len;
494         break;
495 
496       case PSH_BLUE_ALIGN_BOT:
497         /* the bottom of the stem is aligned against a blue zone */
498         hint->cur_pos = align.align_bot;
499         break;
500 
501       case PSH_BLUE_ALIGN_TOP | PSH_BLUE_ALIGN_BOT:
502         /* both edges of the stem are aligned against blue zones */
503         hint->cur_pos = align.align_bot;
504         hint->cur_len = align.align_top - align.align_bot;
505         break;
506 
507       default:
508         {
509           PSH_Hint  parent = hint->parent;
510 
511 
512           if ( parent )
513           {
514             FT_Pos  par_org_center, par_cur_center;
515             FT_Pos  cur_org_center, cur_delta;
516 
517 
518             /* ensure that parent is already fitted */
519             if ( !psh_hint_is_fitted( parent ) )
520               psh_hint_align( parent, globals, dimension, glyph );
521 
522             /* keep original relation between hints, this is, use the */
523             /* scaled distance between the centers of the hints to    */
524             /* compute the new position                               */
525             par_org_center = parent->org_pos + ( parent->org_len >> 1 );
526             par_cur_center = parent->cur_pos + ( parent->cur_len >> 1 );
527             cur_org_center = hint->org_pos   + ( hint->org_len   >> 1 );
528 
529             cur_delta = FT_MulFix( cur_org_center - par_org_center, scale );
530             pos       = par_cur_center + cur_delta - ( len >> 1 );
531           }
532 
533           hint->cur_pos = pos;
534           hint->cur_len = fit_len;
535 
536           /* Stem adjustment tries to snap stem widths to standard
537            * ones.  This is important to prevent unpleasant rounding
538            * artefacts.
539            */
540           if ( glyph->do_stem_adjust )
541           {
542             if ( len <= 64 )
543             {
544               /* the stem is less than one pixel; we will center it
545                * around the nearest pixel center
546                */
547               if ( len >= 32 )
548               {
549                 /* This is a special case where we also widen the stem
550                  * and align it to the pixel grid.
551                  *
552                  *   stem_center          = pos + (len/2)
553                  *   nearest_pixel_center = FT_ROUND(stem_center-32)+32
554                  *   new_pos              = nearest_pixel_center-32
555                  *                        = FT_ROUND(stem_center-32)
556                  *                        = FT_FLOOR(stem_center-32+32)
557                  *                        = FT_FLOOR(stem_center)
558                  *   new_len              = 64
559                  */
560                 pos = FT_PIX_FLOOR( pos + ( len >> 1 ) );
561                 len = 64;
562               }
563               else if ( len > 0 )
564               {
565                 /* This is a very small stem; we simply align it to the
566                  * pixel grid, trying to find the minimal displacement.
567                  *
568                  * left               = pos
569                  * right              = pos + len
570                  * left_nearest_edge  = ROUND(pos)
571                  * right_nearest_edge = ROUND(right)
572                  *
573                  * if ( ABS(left_nearest_edge - left) <=
574                  *      ABS(right_nearest_edge - right) )
575                  *    new_pos = left
576                  * else
577                  *    new_pos = right
578                  */
579                 FT_Pos  left_nearest  = FT_PIX_ROUND( pos );
580                 FT_Pos  right_nearest = FT_PIX_ROUND( pos + len );
581                 FT_Pos  left_disp     = left_nearest - pos;
582                 FT_Pos  right_disp    = right_nearest - ( pos + len );
583 
584 
585                 if ( left_disp < 0 )
586                   left_disp = -left_disp;
587                 if ( right_disp < 0 )
588                   right_disp = -right_disp;
589                 if ( left_disp <= right_disp )
590                   pos = left_nearest;
591                 else
592                   pos = right_nearest;
593               }
594               else
595               {
596                 /* this is a ghost stem; we simply round it */
597                 pos = FT_PIX_ROUND( pos );
598               }
599             }
600             else
601             {
602               len = psh_dimension_quantize_len( dim, len, 0 );
603             }
604           }
605 
606           /* now that we have a good hinted stem width, try to position */
607           /* the stem along a pixel grid integer coordinate             */
608           hint->cur_pos = pos + psh_hint_snap_stem_side_delta( pos, len );
609           hint->cur_len = len;
610         }
611       }
612 
613       if ( do_snapping )
614       {
615         pos = hint->cur_pos;
616         len = hint->cur_len;
617 
618         if ( len < 64 )
619           len = 64;
620         else
621           len = FT_PIX_ROUND( len );
622 
623         switch ( align.align )
624         {
625           case PSH_BLUE_ALIGN_TOP:
626             hint->cur_pos = align.align_top - len;
627             hint->cur_len = len;
628             break;
629 
630           case PSH_BLUE_ALIGN_BOT:
631             hint->cur_len = len;
632             break;
633 
634           case PSH_BLUE_ALIGN_BOT | PSH_BLUE_ALIGN_TOP:
635             /* don't touch */
636             break;
637 
638 
639           default:
640             hint->cur_len = len;
641             if ( len & 64 )
642               pos = FT_PIX_FLOOR( pos + ( len >> 1 ) ) + 32;
643             else
644               pos = FT_PIX_ROUND( pos + ( len >> 1 ) );
645 
646             hint->cur_pos = pos - ( len >> 1 );
647             hint->cur_len = len;
648         }
649       }
650 
651       psh_hint_set_fitted( hint );
652 
653 #ifdef DEBUG_HINTER
654       if ( ps_debug_hint_func )
655         ps_debug_hint_func( hint, dimension );
656 #endif
657     }
658   }
659 
660 
661 #if 0  /* not used for now, experimental */
662 
663  /*
664   *  A variant to perform "light" hinting (i.e. FT_RENDER_MODE_LIGHT)
665   *  of stems
666   */
667   static void
668   psh_hint_align_light( PSH_Hint     hint,
669                         PSH_Globals  globals,
670                         FT_Int       dimension,
671                         PSH_Glyph    glyph )
672   {
673     PSH_Dimension  dim   = &globals->dimension[dimension];
674     FT_Fixed       scale = dim->scale_mult;
675     FT_Fixed       delta = dim->scale_delta;
676 
677 
678     if ( !psh_hint_is_fitted( hint ) )
679     {
680       FT_Pos  pos = FT_MulFix( hint->org_pos, scale ) + delta;
681       FT_Pos  len = FT_MulFix( hint->org_len, scale );
682 
683       FT_Pos  fit_len;
684 
685       PSH_AlignmentRec  align;
686 
687 
688       /* ignore stem alignments when requested through the hint flags */
689       if ( ( dimension == 0 && !glyph->do_horz_hints ) ||
690            ( dimension == 1 && !glyph->do_vert_hints ) )
691       {
692         hint->cur_pos = pos;
693         hint->cur_len = len;
694 
695         psh_hint_set_fitted( hint );
696         return;
697       }
698 
699       fit_len = len;
700 
701       hint->cur_len = fit_len;
702 
703       /* check blue zones for horizontal stems */
704       align.align = PSH_BLUE_ALIGN_NONE;
705       align.align_bot = align.align_top = 0;
706 
707       if ( dimension == 1 )
708         psh_blues_snap_stem( &globals->blues,
709                              hint->org_pos + hint->org_len,
710                              hint->org_pos,
711                              &align );
712 
713       switch ( align.align )
714       {
715       case PSH_BLUE_ALIGN_TOP:
716         /* the top of the stem is aligned against a blue zone */
717         hint->cur_pos = align.align_top - fit_len;
718         break;
719 
720       case PSH_BLUE_ALIGN_BOT:
721         /* the bottom of the stem is aligned against a blue zone */
722         hint->cur_pos = align.align_bot;
723         break;
724 
725       case PSH_BLUE_ALIGN_TOP | PSH_BLUE_ALIGN_BOT:
726         /* both edges of the stem are aligned against blue zones */
727         hint->cur_pos = align.align_bot;
728         hint->cur_len = align.align_top - align.align_bot;
729         break;
730 
731       default:
732         {
733           PSH_Hint  parent = hint->parent;
734 
735 
736           if ( parent )
737           {
738             FT_Pos  par_org_center, par_cur_center;
739             FT_Pos  cur_org_center, cur_delta;
740 
741 
742             /* ensure that parent is already fitted */
743             if ( !psh_hint_is_fitted( parent ) )
744               psh_hint_align_light( parent, globals, dimension, glyph );
745 
746             par_org_center = parent->org_pos + ( parent->org_len / 2 );
747             par_cur_center = parent->cur_pos + ( parent->cur_len / 2 );
748             cur_org_center = hint->org_pos   + ( hint->org_len   / 2 );
749 
750             cur_delta = FT_MulFix( cur_org_center - par_org_center, scale );
751             pos       = par_cur_center + cur_delta - ( len >> 1 );
752           }
753 
754           /* Stems less than one pixel wide are easy -- we want to
755            * make them as dark as possible, so they must fall within
756            * one pixel.  If the stem is split between two pixels
757            * then snap the edge that is nearer to the pixel boundary
758            * to the pixel boundary.
759            */
760           if ( len <= 64 )
761           {
762             if ( ( pos + len + 63 ) / 64  != pos / 64 + 1 )
763               pos += psh_hint_snap_stem_side_delta ( pos, len );
764           }
765 
766           /* Position stems other to minimize the amount of mid-grays.
767            * There are, in general, two positions that do this,
768            * illustrated as A) and B) below.
769            *
770            *   +                   +                   +                   +
771            *
772            * A)             |--------------------------------|
773            * B)   |--------------------------------|
774            * C)       |--------------------------------|
775            *
776            * Position A) (split the excess stem equally) should be better
777            * for stems of width N + f where f < 0.5.
778            *
779            * Position B) (split the deficiency equally) should be better
780            * for stems of width N + f where f > 0.5.
781            *
782            * It turns out though that minimizing the total number of lit
783            * pixels is also important, so position C), with one edge
784            * aligned with a pixel boundary is actually preferable
785            * to A).  There are also more possibile positions for C) than
786            * for A) or B), so it involves less distortion of the overall
787            * character shape.
788            */
789           else /* len > 64 */
790           {
791             FT_Fixed  frac_len = len & 63;
792             FT_Fixed  center = pos + ( len >> 1 );
793             FT_Fixed  delta_a, delta_b;
794 
795 
796             if ( ( len / 64 ) & 1 )
797             {
798               delta_a = FT_PIX_FLOOR( center ) + 32 - center;
799               delta_b = FT_PIX_ROUND( center ) - center;
800             }
801             else
802             {
803               delta_a = FT_PIX_ROUND( center ) - center;
804               delta_b = FT_PIX_FLOOR( center ) + 32 - center;
805             }
806 
807             /* We choose between B) and C) above based on the amount
808              * of fractinal stem width; for small amounts, choose
809              * C) always, for large amounts, B) always, and inbetween,
810              * pick whichever one involves less stem movement.
811              */
812             if ( frac_len < 32 )
813             {
814               pos += psh_hint_snap_stem_side_delta ( pos, len );
815             }
816             else if ( frac_len < 48 )
817             {
818               FT_Fixed  side_delta = psh_hint_snap_stem_side_delta ( pos,
819                                                                      len );
820 
821               if ( FT_ABS( side_delta ) < FT_ABS( delta_b ) )
822                 pos += side_delta;
823               else
824                 pos += delta_b;
825             }
826             else
827             {
828               pos += delta_b;
829             }
830           }
831 
832           hint->cur_pos = pos;
833         }
834       }  /* switch */
835 
836       psh_hint_set_fitted( hint );
837 
838 #ifdef DEBUG_HINTER
839       if ( ps_debug_hint_func )
840         ps_debug_hint_func( hint, dimension );
841 #endif
842     }
843   }
844 
845 #endif /* 0 */
846 
847 
848   static void
psh_hint_table_align_hints(PSH_Hint_Table table,PSH_Globals globals,FT_Int dimension,PSH_Glyph glyph)849   psh_hint_table_align_hints( PSH_Hint_Table  table,
850                               PSH_Globals     globals,
851                               FT_Int          dimension,
852                               PSH_Glyph       glyph )
853   {
854     PSH_Hint       hint;
855     FT_UInt        count;
856 
857 #ifdef DEBUG_HINTER
858 
859     PSH_Dimension  dim   = &globals->dimension[dimension];
860     FT_Fixed       scale = dim->scale_mult;
861     FT_Fixed       delta = dim->scale_delta;
862 
863 
864     if ( ps_debug_no_vert_hints && dimension == 0 )
865     {
866       ps_simple_scale( table, scale, delta, dimension );
867       return;
868     }
869 
870     if ( ps_debug_no_horz_hints && dimension == 1 )
871     {
872       ps_simple_scale( table, scale, delta, dimension );
873       return;
874     }
875 
876 #endif /* DEBUG_HINTER*/
877 
878     hint  = table->hints;
879     count = table->max_hints;
880 
881     for ( ; count > 0; count--, hint++ )
882       psh_hint_align( hint, globals, dimension, glyph );
883   }
884 
885 
886   /*************************************************************************/
887   /*************************************************************************/
888   /*****                                                               *****/
889   /*****                POINTS INTERPOLATION ROUTINES                  *****/
890   /*****                                                               *****/
891   /*************************************************************************/
892   /*************************************************************************/
893 
894 #define PSH_ZONE_MIN  -3200000L
895 #define PSH_ZONE_MAX  +3200000L
896 
897 #define xxDEBUG_ZONES
898 
899 
900 #ifdef DEBUG_ZONES
901 
902 #include FT_CONFIG_STANDARD_LIBRARY_H
903 
904   static void
psh_print_zone(PSH_Zone zone)905   psh_print_zone( PSH_Zone  zone )
906   {
907     printf( "zone [scale,delta,min,max] = [%.3f,%.3f,%d,%d]\n",
908              zone->scale / 65536.0,
909              zone->delta / 64.0,
910              zone->min,
911              zone->max );
912   }
913 
914 #else
915 
916 #define psh_print_zone( x )  do { } while ( 0 )
917 
918 #endif /* DEBUG_ZONES */
919 
920 
921   /*************************************************************************/
922   /*************************************************************************/
923   /*****                                                               *****/
924   /*****                    HINTER GLYPH MANAGEMENT                    *****/
925   /*****                                                               *****/
926   /*************************************************************************/
927   /*************************************************************************/
928 
929 #if 1
930 
931 #define  psh_corner_is_flat      ft_corner_is_flat
932 #define  psh_corner_orientation  ft_corner_orientation
933 
934 #else
935 
936   FT_LOCAL_DEF( FT_Int )
psh_corner_is_flat(FT_Pos x_in,FT_Pos y_in,FT_Pos x_out,FT_Pos y_out)937   psh_corner_is_flat( FT_Pos  x_in,
938                       FT_Pos  y_in,
939                       FT_Pos  x_out,
940                       FT_Pos  y_out )
941   {
942     FT_Pos  ax = x_in;
943     FT_Pos  ay = y_in;
944 
945     FT_Pos  d_in, d_out, d_corner;
946 
947 
948     if ( ax < 0 )
949       ax = -ax;
950     if ( ay < 0 )
951       ay = -ay;
952     d_in = ax + ay;
953 
954     ax = x_out;
955     if ( ax < 0 )
956       ax = -ax;
957     ay = y_out;
958     if ( ay < 0 )
959       ay = -ay;
960     d_out = ax + ay;
961 
962     ax = x_out + x_in;
963     if ( ax < 0 )
964       ax = -ax;
965     ay = y_out + y_in;
966     if ( ay < 0 )
967       ay = -ay;
968     d_corner = ax + ay;
969 
970     return ( d_in + d_out - d_corner ) < ( d_corner >> 4 );
971   }
972 
973   static FT_Int
psh_corner_orientation(FT_Pos in_x,FT_Pos in_y,FT_Pos out_x,FT_Pos out_y)974   psh_corner_orientation( FT_Pos  in_x,
975                           FT_Pos  in_y,
976                           FT_Pos  out_x,
977                           FT_Pos  out_y )
978   {
979     FT_Int  result;
980 
981 
982     /* deal with the trivial cases quickly */
983     if ( in_y == 0 )
984     {
985       if ( in_x >= 0 )
986         result = out_y;
987       else
988         result = -out_y;
989     }
990     else if ( in_x == 0 )
991     {
992       if ( in_y >= 0 )
993         result = -out_x;
994       else
995         result = out_x;
996     }
997     else if ( out_y == 0 )
998     {
999       if ( out_x >= 0 )
1000         result = in_y;
1001       else
1002         result = -in_y;
1003     }
1004     else if ( out_x == 0 )
1005     {
1006       if ( out_y >= 0 )
1007         result = -in_x;
1008       else
1009         result =  in_x;
1010     }
1011     else /* general case */
1012     {
1013       long long  delta = (long long)in_x * out_y - (long long)in_y * out_x;
1014 
1015       if ( delta == 0 )
1016         result = 0;
1017       else
1018         result = 1 - 2 * ( delta < 0 );
1019     }
1020 
1021     return result;
1022   }
1023 
1024 #endif /* !1 */
1025 
1026 
1027 #ifdef COMPUTE_INFLEXS
1028 
1029   /* compute all inflex points in a given glyph */
1030   static void
psh_glyph_compute_inflections(PSH_Glyph glyph)1031   psh_glyph_compute_inflections( PSH_Glyph  glyph )
1032   {
1033     FT_UInt  n;
1034 
1035 
1036     for ( n = 0; n < glyph->num_contours; n++ )
1037     {
1038       PSH_Point  first, start, end, before, after;
1039       FT_Pos     in_x, in_y, out_x, out_y;
1040       FT_Int     orient_prev, orient_cur;
1041       FT_Int     finished = 0;
1042 
1043 
1044       /* we need at least 4 points to create an inflection point */
1045       if ( glyph->contours[n].count < 4 )
1046         continue;
1047 
1048       /* compute first segment in contour */
1049       first = glyph->contours[n].start;
1050 
1051       start = end = first;
1052       do
1053       {
1054         end = end->next;
1055         if ( end == first )
1056           goto Skip;
1057 
1058         in_x = end->org_u - start->org_u;
1059         in_y = end->org_v - start->org_v;
1060 
1061       } while ( in_x == 0 && in_y == 0 );
1062 
1063       /* extend the segment start whenever possible */
1064       before = start;
1065       do
1066       {
1067         do
1068         {
1069           start  = before;
1070           before = before->prev;
1071           if ( before == first )
1072             goto Skip;
1073 
1074           out_x = start->org_u - before->org_u;
1075           out_y = start->org_v - before->org_v;
1076 
1077         } while ( out_x == 0 && out_y == 0 );
1078 
1079         orient_prev = psh_corner_orientation( in_x, in_y, out_x, out_y );
1080 
1081       } while ( orient_prev == 0 );
1082 
1083       first = start;
1084       in_x  = out_x;
1085       in_y  = out_y;
1086 
1087       /* now, process all segments in the contour */
1088       do
1089       {
1090         /* first, extend current segment's end whenever possible */
1091         after = end;
1092         do
1093         {
1094           do
1095           {
1096             end   = after;
1097             after = after->next;
1098             if ( after == first )
1099               finished = 1;
1100 
1101             out_x = after->org_u - end->org_u;
1102             out_y = after->org_v - end->org_v;
1103 
1104           } while ( out_x == 0 && out_y == 0 );
1105 
1106           orient_cur = psh_corner_orientation( in_x, in_y, out_x, out_y );
1107 
1108         } while ( orient_cur == 0 );
1109 
1110         if ( ( orient_cur ^ orient_prev ) < 0 )
1111         {
1112           do
1113           {
1114             psh_point_set_inflex( start );
1115             start = start->next;
1116           }
1117           while ( start != end );
1118 
1119           psh_point_set_inflex( start );
1120         }
1121 
1122         start       = end;
1123         end         = after;
1124         orient_prev = orient_cur;
1125         in_x        = out_x;
1126         in_y        = out_y;
1127 
1128       } while ( !finished );
1129 
1130     Skip:
1131       ;
1132     }
1133   }
1134 
1135 #endif /* COMPUTE_INFLEXS */
1136 
1137 
1138   static void
psh_glyph_done(PSH_Glyph glyph)1139   psh_glyph_done( PSH_Glyph  glyph )
1140   {
1141     FT_Memory  memory = glyph->memory;
1142 
1143 
1144     psh_hint_table_done( &glyph->hint_tables[1], memory );
1145     psh_hint_table_done( &glyph->hint_tables[0], memory );
1146 
1147     FT_FREE( glyph->points );
1148     FT_FREE( glyph->contours );
1149 
1150     glyph->num_points   = 0;
1151     glyph->num_contours = 0;
1152 
1153     glyph->memory = 0;
1154   }
1155 
1156 
1157   static int
psh_compute_dir(FT_Pos dx,FT_Pos dy)1158   psh_compute_dir( FT_Pos  dx,
1159                    FT_Pos  dy )
1160   {
1161     FT_Pos  ax, ay;
1162     int     result = PSH_DIR_NONE;
1163 
1164 
1165     ax = ( dx >= 0 ) ? dx : -dx;
1166     ay = ( dy >= 0 ) ? dy : -dy;
1167 
1168     if ( ay * 12 < ax )
1169     {
1170       /* |dy| <<< |dx|  means a near-horizontal segment */
1171       result = ( dx >= 0 ) ? PSH_DIR_RIGHT : PSH_DIR_LEFT;
1172     }
1173     else if ( ax * 12 < ay )
1174     {
1175       /* |dx| <<< |dy|  means a near-vertical segment */
1176       result = ( dy >= 0 ) ? PSH_DIR_UP : PSH_DIR_DOWN;
1177     }
1178 
1179     return result;
1180   }
1181 
1182 
1183   /* load outline point coordinates into hinter glyph */
1184   static void
psh_glyph_load_points(PSH_Glyph glyph,FT_Int dimension)1185   psh_glyph_load_points( PSH_Glyph  glyph,
1186                          FT_Int     dimension )
1187   {
1188     FT_Vector*  vec   = glyph->outline->points;
1189     PSH_Point   point = glyph->points;
1190     FT_UInt     count = glyph->num_points;
1191 
1192 
1193     for ( ; count > 0; count--, point++, vec++ )
1194     {
1195       point->flags2 = 0;
1196       point->hint   = NULL;
1197       if ( dimension == 0 )
1198       {
1199         point->org_u = vec->x;
1200         point->org_v = vec->y;
1201       }
1202       else
1203       {
1204         point->org_u = vec->y;
1205         point->org_v = vec->x;
1206       }
1207 
1208 #ifdef DEBUG_HINTER
1209       point->org_x = vec->x;
1210       point->org_y = vec->y;
1211 #endif
1212 
1213     }
1214   }
1215 
1216 
1217   /* save hinted point coordinates back to outline */
1218   static void
psh_glyph_save_points(PSH_Glyph glyph,FT_Int dimension)1219   psh_glyph_save_points( PSH_Glyph  glyph,
1220                          FT_Int     dimension )
1221   {
1222     FT_UInt     n;
1223     PSH_Point   point = glyph->points;
1224     FT_Vector*  vec   = glyph->outline->points;
1225     char*       tags  = glyph->outline->tags;
1226 
1227 
1228     for ( n = 0; n < glyph->num_points; n++ )
1229     {
1230       if ( dimension == 0 )
1231         vec[n].x = point->cur_u;
1232       else
1233         vec[n].y = point->cur_u;
1234 
1235       if ( psh_point_is_strong( point ) )
1236         tags[n] |= (char)( ( dimension == 0 ) ? 32 : 64 );
1237 
1238 #ifdef DEBUG_HINTER
1239 
1240       if ( dimension == 0 )
1241       {
1242         point->cur_x   = point->cur_u;
1243         point->flags_x = point->flags2 | point->flags;
1244       }
1245       else
1246       {
1247         point->cur_y   = point->cur_u;
1248         point->flags_y = point->flags2 | point->flags;
1249       }
1250 
1251 #endif
1252 
1253       point++;
1254     }
1255   }
1256 
1257 
1258   static FT_Error
psh_glyph_init(PSH_Glyph glyph,FT_Outline * outline,PS_Hints ps_hints,PSH_Globals globals)1259   psh_glyph_init( PSH_Glyph    glyph,
1260                   FT_Outline*  outline,
1261                   PS_Hints     ps_hints,
1262                   PSH_Globals  globals )
1263   {
1264     FT_Error   error;
1265     FT_Memory  memory;
1266 
1267 
1268     /* clear all fields */
1269     FT_MEM_ZERO( glyph, sizeof ( *glyph ) );
1270 
1271     memory = glyph->memory = globals->memory;
1272 
1273     /* allocate and setup points + contours arrays */
1274     if ( FT_NEW_ARRAY( glyph->points,   outline->n_points   ) ||
1275          FT_NEW_ARRAY( glyph->contours, outline->n_contours ) )
1276       goto Exit;
1277 
1278     glyph->num_points   = outline->n_points;
1279     glyph->num_contours = outline->n_contours;
1280 
1281     {
1282       FT_UInt      first = 0, next, n;
1283       PSH_Point    points  = glyph->points;
1284       PSH_Contour  contour = glyph->contours;
1285 
1286 
1287       for ( n = 0; n < glyph->num_contours; n++ )
1288       {
1289         FT_Int     count;
1290         PSH_Point  point;
1291 
1292 
1293         next  = outline->contours[n] + 1;
1294         count = next - first;
1295 
1296         contour->start = points + first;
1297         contour->count = (FT_UInt)count;
1298 
1299         if ( count > 0 )
1300         {
1301           point = points + first;
1302 
1303           point->prev    = points + next - 1;
1304           point->contour = contour;
1305 
1306           for ( ; count > 1; count-- )
1307           {
1308             point[0].next = point + 1;
1309             point[1].prev = point;
1310             point++;
1311             point->contour = contour;
1312           }
1313           point->next = points + first;
1314         }
1315 
1316         contour++;
1317         first = next;
1318       }
1319     }
1320 
1321     {
1322       PSH_Point   points = glyph->points;
1323       PSH_Point   point  = points;
1324       FT_Vector*  vec    = outline->points;
1325       FT_UInt     n;
1326 
1327 
1328       for ( n = 0; n < glyph->num_points; n++, point++ )
1329       {
1330         FT_Int  n_prev = (FT_Int)( point->prev - points );
1331         FT_Int  n_next = (FT_Int)( point->next - points );
1332         FT_Pos  dxi, dyi, dxo, dyo;
1333 
1334 
1335         if ( !( outline->tags[n] & FT_CURVE_TAG_ON ) )
1336           point->flags = PSH_POINT_OFF;
1337 
1338         dxi = vec[n].x - vec[n_prev].x;
1339         dyi = vec[n].y - vec[n_prev].y;
1340 
1341         point->dir_in = (FT_Char)psh_compute_dir( dxi, dyi );
1342 
1343         dxo = vec[n_next].x - vec[n].x;
1344         dyo = vec[n_next].y - vec[n].y;
1345 
1346         point->dir_out = (FT_Char)psh_compute_dir( dxo, dyo );
1347 
1348         /* detect smooth points */
1349         if ( point->flags & PSH_POINT_OFF )
1350           point->flags |= PSH_POINT_SMOOTH;
1351 
1352         else if ( point->dir_in == point->dir_out )
1353         {
1354           if ( point->dir_out != PSH_DIR_NONE           ||
1355                psh_corner_is_flat( dxi, dyi, dxo, dyo ) )
1356             point->flags |= PSH_POINT_SMOOTH;
1357         }
1358       }
1359     }
1360 
1361     glyph->outline = outline;
1362     glyph->globals = globals;
1363 
1364 #ifdef COMPUTE_INFLEXS
1365     psh_glyph_load_points( glyph, 0 );
1366     psh_glyph_compute_inflections( glyph );
1367 #endif /* COMPUTE_INFLEXS */
1368 
1369     /* now deal with hints tables */
1370     error = psh_hint_table_init( &glyph->hint_tables [0],
1371                                  &ps_hints->dimension[0].hints,
1372                                  &ps_hints->dimension[0].masks,
1373                                  &ps_hints->dimension[0].counters,
1374                                  memory );
1375     if ( error )
1376       goto Exit;
1377 
1378     error = psh_hint_table_init( &glyph->hint_tables [1],
1379                                  &ps_hints->dimension[1].hints,
1380                                  &ps_hints->dimension[1].masks,
1381                                  &ps_hints->dimension[1].counters,
1382                                  memory );
1383     if ( error )
1384       goto Exit;
1385 
1386   Exit:
1387     return error;
1388   }
1389 
1390 
1391   /* compute all extrema in a glyph for a given dimension */
1392   static void
psh_glyph_compute_extrema(PSH_Glyph glyph)1393   psh_glyph_compute_extrema( PSH_Glyph  glyph )
1394   {
1395     FT_UInt  n;
1396 
1397 
1398     /* first of all, compute all local extrema */
1399     for ( n = 0; n < glyph->num_contours; n++ )
1400     {
1401       PSH_Point  first = glyph->contours[n].start;
1402       PSH_Point  point, before, after;
1403 
1404 
1405       if ( glyph->contours[n].count == 0 )
1406         continue;
1407 
1408       point  = first;
1409       before = point;
1410       after  = point;
1411 
1412       do
1413       {
1414         before = before->prev;
1415         if ( before == first )
1416           goto Skip;
1417 
1418       } while ( before->org_u == point->org_u );
1419 
1420       first = point = before->next;
1421 
1422       for (;;)
1423       {
1424         after = point;
1425         do
1426         {
1427           after = after->next;
1428           if ( after == first )
1429             goto Next;
1430 
1431         } while ( after->org_u == point->org_u );
1432 
1433         if ( before->org_u < point->org_u )
1434         {
1435           if ( after->org_u < point->org_u )
1436           {
1437             /* local maximum */
1438             goto Extremum;
1439           }
1440         }
1441         else /* before->org_u > point->org_u */
1442         {
1443           if ( after->org_u > point->org_u )
1444           {
1445             /* local minimum */
1446           Extremum:
1447             do
1448             {
1449               psh_point_set_extremum( point );
1450               point = point->next;
1451 
1452             } while ( point != after );
1453           }
1454         }
1455 
1456         before = after->prev;
1457         point  = after;
1458 
1459       } /* for  */
1460 
1461     Next:
1462       ;
1463     }
1464 
1465     /* for each extremum, determine its direction along the */
1466     /* orthogonal axis                                      */
1467     for ( n = 0; n < glyph->num_points; n++ )
1468     {
1469       PSH_Point  point, before, after;
1470 
1471 
1472       point  = &glyph->points[n];
1473       before = point;
1474       after  = point;
1475 
1476       if ( psh_point_is_extremum( point ) )
1477       {
1478         do
1479         {
1480           before = before->prev;
1481           if ( before == point )
1482             goto Skip;
1483 
1484         } while ( before->org_v == point->org_v );
1485 
1486         do
1487         {
1488           after = after->next;
1489           if ( after == point )
1490             goto Skip;
1491 
1492         } while ( after->org_v == point->org_v );
1493       }
1494 
1495       if ( before->org_v < point->org_v &&
1496            after->org_v  > point->org_v )
1497       {
1498         psh_point_set_positive( point );
1499       }
1500       else if ( before->org_v > point->org_v &&
1501                 after->org_v  < point->org_v )
1502       {
1503         psh_point_set_negative( point );
1504       }
1505 
1506     Skip:
1507       ;
1508     }
1509   }
1510 
1511 
1512   /* major_dir is the direction for points on the bottom/left of the stem; */
1513   /* Points on the top/right of the stem will have a direction of          */
1514   /* -major_dir.                                                           */
1515 
1516   static void
psh_hint_table_find_strong_points(PSH_Hint_Table table,PSH_Point point,FT_UInt count,FT_Int threshold,FT_Int major_dir)1517   psh_hint_table_find_strong_points( PSH_Hint_Table  table,
1518                                      PSH_Point       point,
1519                                      FT_UInt         count,
1520                                      FT_Int          threshold,
1521                                      FT_Int          major_dir )
1522   {
1523     PSH_Hint*  sort      = table->sort;
1524     FT_UInt    num_hints = table->num_hints;
1525 
1526 
1527     for ( ; count > 0; count--, point++ )
1528     {
1529       FT_Int  point_dir = 0;
1530       FT_Pos  org_u     = point->org_u;
1531 
1532 
1533       if ( psh_point_is_strong( point ) )
1534         continue;
1535 
1536       if ( PSH_DIR_COMPARE( point->dir_in, major_dir ) )
1537         point_dir = point->dir_in;
1538 
1539       else if ( PSH_DIR_COMPARE( point->dir_out, major_dir ) )
1540         point_dir = point->dir_out;
1541 
1542       if ( point_dir )
1543       {
1544         if ( point_dir == major_dir )
1545         {
1546           FT_UInt  nn;
1547 
1548 
1549           for ( nn = 0; nn < num_hints; nn++ )
1550           {
1551             PSH_Hint  hint = sort[nn];
1552             FT_Pos    d    = org_u - hint->org_pos;
1553 
1554 
1555             if ( d < threshold && -d < threshold )
1556             {
1557               psh_point_set_strong( point );
1558               point->flags2 |= PSH_POINT_EDGE_MIN;
1559               point->hint    = hint;
1560               break;
1561             }
1562           }
1563         }
1564         else if ( point_dir == -major_dir )
1565         {
1566           FT_UInt  nn;
1567 
1568 
1569           for ( nn = 0; nn < num_hints; nn++ )
1570           {
1571             PSH_Hint  hint = sort[nn];
1572             FT_Pos    d    = org_u - hint->org_pos - hint->org_len;
1573 
1574 
1575             if ( d < threshold && -d < threshold )
1576             {
1577               psh_point_set_strong( point );
1578               point->flags2 |= PSH_POINT_EDGE_MAX;
1579               point->hint    = hint;
1580               break;
1581             }
1582           }
1583         }
1584       }
1585 
1586 #if 1
1587       else if ( psh_point_is_extremum( point ) )
1588       {
1589         /* treat extrema as special cases for stem edge alignment */
1590         FT_UInt  nn, min_flag, max_flag;
1591 
1592 
1593         if ( major_dir == PSH_DIR_HORIZONTAL )
1594         {
1595           min_flag = PSH_POINT_POSITIVE;
1596           max_flag = PSH_POINT_NEGATIVE;
1597         }
1598         else
1599         {
1600           min_flag = PSH_POINT_NEGATIVE;
1601           max_flag = PSH_POINT_POSITIVE;
1602         }
1603 
1604         if ( point->flags2 & min_flag )
1605         {
1606           for ( nn = 0; nn < num_hints; nn++ )
1607           {
1608             PSH_Hint  hint = sort[nn];
1609             FT_Pos    d    = org_u - hint->org_pos;
1610 
1611 
1612             if ( d < threshold && -d < threshold )
1613             {
1614               point->flags2 |= PSH_POINT_EDGE_MIN;
1615               point->hint    = hint;
1616               psh_point_set_strong( point );
1617               break;
1618             }
1619           }
1620         }
1621         else if ( point->flags2 & max_flag )
1622         {
1623           for ( nn = 0; nn < num_hints; nn++ )
1624           {
1625             PSH_Hint  hint = sort[nn];
1626             FT_Pos    d    = org_u - hint->org_pos - hint->org_len;
1627 
1628 
1629             if ( d < threshold && -d < threshold )
1630             {
1631               point->flags2 |= PSH_POINT_EDGE_MAX;
1632               point->hint    = hint;
1633               psh_point_set_strong( point );
1634               break;
1635             }
1636           }
1637         }
1638 
1639         if ( point->hint == NULL )
1640         {
1641           for ( nn = 0; nn < num_hints; nn++ )
1642           {
1643             PSH_Hint  hint = sort[nn];
1644 
1645 
1646             if ( org_u >= hint->org_pos                 &&
1647                 org_u <= hint->org_pos + hint->org_len )
1648             {
1649               point->hint = hint;
1650               break;
1651             }
1652           }
1653         }
1654       }
1655 
1656 #endif /* 1 */
1657     }
1658   }
1659 
1660 
1661   /* the accepted shift for strong points in fractional pixels */
1662 #define PSH_STRONG_THRESHOLD  32
1663 
1664   /* the maximum shift value in font units */
1665 #define PSH_STRONG_THRESHOLD_MAXIMUM  30
1666 
1667 
1668   /* find strong points in a glyph */
1669   static void
psh_glyph_find_strong_points(PSH_Glyph glyph,FT_Int dimension)1670   psh_glyph_find_strong_points( PSH_Glyph  glyph,
1671                                 FT_Int     dimension )
1672   {
1673     /* a point is `strong' if it is located on a stem edge and       */
1674     /* has an `in' or `out' tangent parallel to the hint's direction */
1675 
1676     PSH_Hint_Table  table     = &glyph->hint_tables[dimension];
1677     PS_Mask         mask      = table->hint_masks->masks;
1678     FT_UInt         num_masks = table->hint_masks->num_masks;
1679     FT_UInt         first     = 0;
1680     FT_Int          major_dir = dimension == 0 ? PSH_DIR_VERTICAL
1681                                                : PSH_DIR_HORIZONTAL;
1682     PSH_Dimension   dim       = &glyph->globals->dimension[dimension];
1683     FT_Fixed        scale     = dim->scale_mult;
1684     FT_Int          threshold;
1685 
1686 
1687     threshold = (FT_Int)FT_DivFix( PSH_STRONG_THRESHOLD, scale );
1688     if ( threshold > PSH_STRONG_THRESHOLD_MAXIMUM )
1689       threshold = PSH_STRONG_THRESHOLD_MAXIMUM;
1690 
1691     /* process secondary hints to `selected' points */
1692     if ( num_masks > 1 && glyph->num_points > 0 )
1693     {
1694       /* the `endchar' op can reduce the number of points */
1695       first = mask->end_point > glyph->num_points
1696                 ? glyph->num_points
1697                 : mask->end_point;
1698       mask++;
1699       for ( ; num_masks > 1; num_masks--, mask++ )
1700       {
1701         FT_UInt  next;
1702         FT_Int   count;
1703 
1704 
1705         next  = mask->end_point > glyph->num_points
1706                   ? glyph->num_points
1707                   : mask->end_point;
1708         count = next - first;
1709         if ( count > 0 )
1710         {
1711           PSH_Point  point = glyph->points + first;
1712 
1713 
1714           psh_hint_table_activate_mask( table, mask );
1715 
1716           psh_hint_table_find_strong_points( table, point, count,
1717                                              threshold, major_dir );
1718         }
1719         first = next;
1720       }
1721     }
1722 
1723     /* process primary hints for all points */
1724     if ( num_masks == 1 )
1725     {
1726       FT_UInt    count = glyph->num_points;
1727       PSH_Point  point = glyph->points;
1728 
1729 
1730       psh_hint_table_activate_mask( table, table->hint_masks->masks );
1731 
1732       psh_hint_table_find_strong_points( table, point, count,
1733                                          threshold, major_dir );
1734     }
1735 
1736     /* now, certain points may have been attached to a hint and */
1737     /* not marked as strong; update their flags then            */
1738     {
1739       FT_UInt    count = glyph->num_points;
1740       PSH_Point  point = glyph->points;
1741 
1742 
1743       for ( ; count > 0; count--, point++ )
1744         if ( point->hint && !psh_point_is_strong( point ) )
1745           psh_point_set_strong( point );
1746     }
1747   }
1748 
1749 
1750   /* find points in a glyph which are in a blue zone and have `in' or */
1751   /* `out' tangents parallel to the horizontal axis                   */
1752   static void
psh_glyph_find_blue_points(PSH_Blues blues,PSH_Glyph glyph)1753   psh_glyph_find_blue_points( PSH_Blues  blues,
1754                               PSH_Glyph  glyph )
1755   {
1756     PSH_Blue_Table  table;
1757     PSH_Blue_Zone   zone;
1758     FT_UInt         glyph_count = glyph->num_points;
1759     FT_UInt         blue_count;
1760     PSH_Point       point = glyph->points;
1761 
1762 
1763     for ( ; glyph_count > 0; glyph_count--, point++ )
1764     {
1765       FT_Pos  y;
1766 
1767 
1768       /* check tangents */
1769       if ( !PSH_DIR_COMPARE( point->dir_in,  PSH_DIR_HORIZONTAL ) &&
1770            !PSH_DIR_COMPARE( point->dir_out, PSH_DIR_HORIZONTAL ) )
1771         continue;
1772 
1773       /* skip strong points */
1774       if ( psh_point_is_strong( point ) )
1775         continue;
1776 
1777       y = point->org_u;
1778 
1779       /* look up top zones */
1780       table      = &blues->normal_top;
1781       blue_count = table->count;
1782       zone       = table->zones;
1783 
1784       for ( ; blue_count > 0; blue_count--, zone++ )
1785       {
1786         FT_Pos  delta = y - zone->org_bottom;
1787 
1788 
1789         if ( delta < -blues->blue_fuzz )
1790           break;
1791 
1792         if ( y <= zone->org_top + blues->blue_fuzz )
1793           if ( blues->no_overshoots || delta <= blues->blue_threshold )
1794           {
1795             point->cur_u = zone->cur_bottom;
1796             psh_point_set_strong( point );
1797             psh_point_set_fitted( point );
1798           }
1799       }
1800 
1801       /* look up bottom zones */
1802       table      = &blues->normal_bottom;
1803       blue_count = table->count;
1804       zone       = table->zones + blue_count - 1;
1805 
1806       for ( ; blue_count > 0; blue_count--, zone-- )
1807       {
1808         FT_Pos  delta = zone->org_top - y;
1809 
1810 
1811         if ( delta < -blues->blue_fuzz )
1812           break;
1813 
1814         if ( y >= zone->org_bottom - blues->blue_fuzz )
1815           if ( blues->no_overshoots || delta < blues->blue_threshold )
1816           {
1817             point->cur_u = zone->cur_top;
1818             psh_point_set_strong( point );
1819             psh_point_set_fitted( point );
1820           }
1821       }
1822     }
1823   }
1824 
1825 
1826   /* interpolate strong points with the help of hinted coordinates */
1827   static void
psh_glyph_interpolate_strong_points(PSH_Glyph glyph,FT_Int dimension)1828   psh_glyph_interpolate_strong_points( PSH_Glyph  glyph,
1829                                        FT_Int     dimension )
1830   {
1831     PSH_Dimension  dim   = &glyph->globals->dimension[dimension];
1832     FT_Fixed       scale = dim->scale_mult;
1833 
1834     FT_UInt        count = glyph->num_points;
1835     PSH_Point      point = glyph->points;
1836 
1837 
1838     for ( ; count > 0; count--, point++ )
1839     {
1840       PSH_Hint  hint = point->hint;
1841 
1842 
1843       if ( hint )
1844       {
1845         FT_Pos  delta;
1846 
1847 
1848         if ( psh_point_is_edge_min( point ) )
1849           point->cur_u = hint->cur_pos;
1850 
1851         else if ( psh_point_is_edge_max( point ) )
1852           point->cur_u = hint->cur_pos + hint->cur_len;
1853 
1854         else
1855         {
1856           delta = point->org_u - hint->org_pos;
1857 
1858           if ( delta <= 0 )
1859             point->cur_u = hint->cur_pos + FT_MulFix( delta, scale );
1860 
1861           else if ( delta >= hint->org_len )
1862             point->cur_u = hint->cur_pos + hint->cur_len +
1863                              FT_MulFix( delta - hint->org_len, scale );
1864 
1865           else if ( hint->org_len > 0 )
1866             point->cur_u = hint->cur_pos +
1867                              FT_MulDiv( delta, hint->cur_len,
1868                                         hint->org_len );
1869           else
1870             point->cur_u = hint->cur_pos;
1871         }
1872         psh_point_set_fitted( point );
1873       }
1874     }
1875   }
1876 
1877 
1878 #define  PSH_MAX_STRONG_INTERNAL  16
1879 
1880   static void
psh_glyph_interpolate_normal_points(PSH_Glyph glyph,FT_Int dimension)1881   psh_glyph_interpolate_normal_points( PSH_Glyph  glyph,
1882                                        FT_Int     dimension )
1883   {
1884 
1885 #if 1
1886     /* first technique: a point is strong if it is a local extremum */
1887 
1888     PSH_Dimension  dim    = &glyph->globals->dimension[dimension];
1889     FT_Fixed       scale  = dim->scale_mult;
1890     FT_Memory      memory = glyph->memory;
1891 
1892     PSH_Point*     strongs     = NULL;
1893     PSH_Point      strongs_0[PSH_MAX_STRONG_INTERNAL];
1894     FT_UInt        num_strongs = 0;
1895 
1896     PSH_Point      points = glyph->points;
1897     PSH_Point      points_end = points + glyph->num_points;
1898     PSH_Point      point;
1899 
1900 
1901     /* first count the number of strong points */
1902     for ( point = points; point < points_end; point++ )
1903     {
1904       if ( psh_point_is_strong( point ) )
1905         num_strongs++;
1906     }
1907 
1908     if ( num_strongs == 0 )  /* nothing to do here */
1909       return;
1910 
1911     /* allocate an array to store a list of points, */
1912     /* stored in increasing org_u order             */
1913     if ( num_strongs <= PSH_MAX_STRONG_INTERNAL )
1914       strongs = strongs_0;
1915     else
1916     {
1917       FT_Error  error;
1918 
1919 
1920       if ( FT_NEW_ARRAY( strongs, num_strongs ) )
1921         return;
1922     }
1923 
1924     num_strongs = 0;
1925     for ( point = points; point < points_end; point++ )
1926     {
1927       PSH_Point*  insert;
1928 
1929 
1930       if ( !psh_point_is_strong( point ) )
1931         continue;
1932 
1933       for ( insert = strongs + num_strongs; insert > strongs; insert-- )
1934       {
1935         if ( insert[-1]->org_u <= point->org_u )
1936           break;
1937 
1938         insert[0] = insert[-1];
1939       }
1940       insert[0] = point;
1941       num_strongs++;
1942     }
1943 
1944     /* now try to interpolate all normal points */
1945     for ( point = points; point < points_end; point++ )
1946     {
1947       if ( psh_point_is_strong( point ) )
1948         continue;
1949 
1950       /* sometimes, some local extrema are smooth points */
1951       if ( psh_point_is_smooth( point ) )
1952       {
1953         if ( point->dir_in == PSH_DIR_NONE   ||
1954              point->dir_in != point->dir_out )
1955           continue;
1956 
1957         if ( !psh_point_is_extremum( point ) &&
1958              !psh_point_is_inflex( point )   )
1959           continue;
1960 
1961         point->flags &= ~PSH_POINT_SMOOTH;
1962       }
1963 
1964       /* find best enclosing point coordinates then interpolate */
1965       {
1966         PSH_Point   before, after;
1967         FT_UInt     nn;
1968 
1969 
1970         for ( nn = 0; nn < num_strongs; nn++ )
1971           if ( strongs[nn]->org_u > point->org_u )
1972             break;
1973 
1974         if ( nn == 0 )  /* point before the first strong point */
1975         {
1976           after = strongs[0];
1977 
1978           point->cur_u = after->cur_u +
1979                            FT_MulFix( point->org_u - after->org_u,
1980                                       scale );
1981         }
1982         else
1983         {
1984           before = strongs[nn - 1];
1985 
1986           for ( nn = num_strongs; nn > 0; nn-- )
1987             if ( strongs[nn - 1]->org_u < point->org_u )
1988               break;
1989 
1990           if ( nn == num_strongs )  /* point is after last strong point */
1991           {
1992             before = strongs[nn - 1];
1993 
1994             point->cur_u = before->cur_u +
1995                              FT_MulFix( point->org_u - before->org_u,
1996                                         scale );
1997           }
1998           else
1999           {
2000             FT_Pos  u;
2001 
2002 
2003             after = strongs[nn];
2004 
2005             /* now interpolate point between before and after */
2006             u = point->org_u;
2007 
2008             if ( u == before->org_u )
2009               point->cur_u = before->cur_u;
2010 
2011             else if ( u == after->org_u )
2012               point->cur_u = after->cur_u;
2013 
2014             else
2015               point->cur_u = before->cur_u +
2016                                FT_MulDiv( u - before->org_u,
2017                                           after->cur_u - before->cur_u,
2018                                           after->org_u - before->org_u );
2019           }
2020         }
2021         psh_point_set_fitted( point );
2022       }
2023     }
2024 
2025     if ( strongs != strongs_0 )
2026       FT_FREE( strongs );
2027 
2028 #endif /* 1 */
2029 
2030   }
2031 
2032 
2033   /* interpolate other points */
2034   static void
psh_glyph_interpolate_other_points(PSH_Glyph glyph,FT_Int dimension)2035   psh_glyph_interpolate_other_points( PSH_Glyph  glyph,
2036                                       FT_Int     dimension )
2037   {
2038     PSH_Dimension  dim          = &glyph->globals->dimension[dimension];
2039     FT_Fixed       scale        = dim->scale_mult;
2040     FT_Fixed       delta        = dim->scale_delta;
2041     PSH_Contour    contour      = glyph->contours;
2042     FT_UInt        num_contours = glyph->num_contours;
2043 
2044 
2045     for ( ; num_contours > 0; num_contours--, contour++ )
2046     {
2047       PSH_Point  start = contour->start;
2048       PSH_Point  first, next, point;
2049       FT_UInt    fit_count;
2050 
2051 
2052       /* count the number of strong points in this contour */
2053       next      = start + contour->count;
2054       fit_count = 0;
2055       first     = 0;
2056 
2057       for ( point = start; point < next; point++ )
2058         if ( psh_point_is_fitted( point ) )
2059         {
2060           if ( !first )
2061             first = point;
2062 
2063           fit_count++;
2064         }
2065 
2066       /* if there are less than 2 fitted points in the contour, we */
2067       /* simply scale and eventually translate the contour points  */
2068       if ( fit_count < 2 )
2069       {
2070         if ( fit_count == 1 )
2071           delta = first->cur_u - FT_MulFix( first->org_u, scale );
2072 
2073         for ( point = start; point < next; point++ )
2074           if ( point != first )
2075             point->cur_u = FT_MulFix( point->org_u, scale ) + delta;
2076 
2077         goto Next_Contour;
2078       }
2079 
2080       /* there are more than 2 strong points in this contour; we */
2081       /* need to interpolate weak points between them            */
2082       start = first;
2083       do
2084       {
2085         point = first;
2086 
2087         /* skip consecutive fitted points */
2088         for (;;)
2089         {
2090           next = first->next;
2091           if ( next == start )
2092             goto Next_Contour;
2093 
2094           if ( !psh_point_is_fitted( next ) )
2095             break;
2096 
2097           first = next;
2098         }
2099 
2100         /* find next fitted point after unfitted one */
2101         for (;;)
2102         {
2103           next = next->next;
2104           if ( psh_point_is_fitted( next ) )
2105             break;
2106         }
2107 
2108         /* now interpolate between them */
2109         {
2110           FT_Pos    org_a, org_ab, cur_a, cur_ab;
2111           FT_Pos    org_c, org_ac, cur_c;
2112           FT_Fixed  scale_ab;
2113 
2114 
2115           if ( first->org_u <= next->org_u )
2116           {
2117             org_a  = first->org_u;
2118             cur_a  = first->cur_u;
2119             org_ab = next->org_u - org_a;
2120             cur_ab = next->cur_u - cur_a;
2121           }
2122           else
2123           {
2124             org_a  = next->org_u;
2125             cur_a  = next->cur_u;
2126             org_ab = first->org_u - org_a;
2127             cur_ab = first->cur_u - cur_a;
2128           }
2129 
2130           scale_ab = 0x10000L;
2131           if ( org_ab > 0 )
2132             scale_ab = FT_DivFix( cur_ab, org_ab );
2133 
2134           point = first->next;
2135           do
2136           {
2137             org_c  = point->org_u;
2138             org_ac = org_c - org_a;
2139 
2140             if ( org_ac <= 0 )
2141             {
2142               /* on the left of the interpolation zone */
2143               cur_c = cur_a + FT_MulFix( org_ac, scale );
2144             }
2145             else if ( org_ac >= org_ab )
2146             {
2147               /* on the right on the interpolation zone */
2148               cur_c = cur_a + cur_ab + FT_MulFix( org_ac - org_ab, scale );
2149             }
2150             else
2151             {
2152               /* within the interpolation zone */
2153               cur_c = cur_a + FT_MulFix( org_ac, scale_ab );
2154             }
2155 
2156             point->cur_u = cur_c;
2157 
2158             point = point->next;
2159 
2160           } while ( point != next );
2161         }
2162 
2163         /* keep going until all points in the contours have been processed */
2164         first = next;
2165 
2166       } while ( first != start );
2167 
2168     Next_Contour:
2169       ;
2170     }
2171   }
2172 
2173 
2174   /*************************************************************************/
2175   /*************************************************************************/
2176   /*****                                                               *****/
2177   /*****                     HIGH-LEVEL INTERFACE                      *****/
2178   /*****                                                               *****/
2179   /*************************************************************************/
2180   /*************************************************************************/
2181 
2182   FT_Error
ps_hints_apply(PS_Hints ps_hints,FT_Outline * outline,PSH_Globals globals,FT_Render_Mode hint_mode)2183   ps_hints_apply( PS_Hints        ps_hints,
2184                   FT_Outline*     outline,
2185                   PSH_Globals     globals,
2186                   FT_Render_Mode  hint_mode )
2187   {
2188     PSH_GlyphRec  glyphrec;
2189     PSH_Glyph     glyph = &glyphrec;
2190     FT_Error      error;
2191 #ifdef DEBUG_HINTER
2192     FT_Memory     memory;
2193 #endif
2194     FT_Int        dimension;
2195 
2196 
2197     /* something to do? */
2198     if ( outline->n_points == 0 || outline->n_contours == 0 )
2199       return PSH_Err_Ok;
2200 
2201 #ifdef DEBUG_HINTER
2202 
2203     memory = globals->memory;
2204 
2205     if ( ps_debug_glyph )
2206     {
2207       psh_glyph_done( ps_debug_glyph );
2208       FT_FREE( ps_debug_glyph );
2209     }
2210 
2211     if ( FT_NEW( glyph ) )
2212       return error;
2213 
2214     ps_debug_glyph = glyph;
2215 
2216 #endif /* DEBUG_HINTER */
2217 
2218     error = psh_glyph_init( glyph, outline, ps_hints, globals );
2219     if ( error )
2220       goto Exit;
2221 
2222     /* try to optimize the y_scale so that the top of non-capital letters
2223      * is aligned on a pixel boundary whenever possible
2224      */
2225     {
2226       PSH_Dimension  dim_x = &glyph->globals->dimension[0];
2227       PSH_Dimension  dim_y = &glyph->globals->dimension[1];
2228 
2229       FT_Fixed  x_scale = dim_x->scale_mult;
2230       FT_Fixed  y_scale = dim_y->scale_mult;
2231 
2232       FT_Fixed  old_x_scale = x_scale;
2233       FT_Fixed  old_y_scale = y_scale;
2234 
2235       FT_Fixed  scaled;
2236       FT_Fixed  fitted;
2237 
2238       FT_Bool  rescale = FALSE;
2239 
2240 
2241       scaled = FT_MulFix( globals->blues.normal_top.zones->org_ref, y_scale );
2242       fitted = FT_PIX_ROUND( scaled );
2243 
2244       if ( fitted != 0 && scaled != fitted )
2245       {
2246         rescale = TRUE;
2247 
2248         y_scale = FT_MulDiv( y_scale, fitted, scaled );
2249 
2250         if ( fitted < scaled )
2251           x_scale -= x_scale / 50;
2252 
2253         psh_globals_set_scale( glyph->globals, x_scale, y_scale, 0, 0 );
2254       }
2255 
2256       glyph->do_horz_hints = 1;
2257       glyph->do_vert_hints = 1;
2258 
2259       glyph->do_horz_snapping = FT_BOOL( hint_mode == FT_RENDER_MODE_MONO ||
2260                                          hint_mode == FT_RENDER_MODE_LCD  );
2261 
2262       glyph->do_vert_snapping = FT_BOOL( hint_mode == FT_RENDER_MODE_MONO  ||
2263                                          hint_mode == FT_RENDER_MODE_LCD_V );
2264 
2265       glyph->do_stem_adjust   = FT_BOOL( hint_mode != FT_RENDER_MODE_LIGHT );
2266 
2267       for ( dimension = 0; dimension < 2; dimension++ )
2268       {
2269         /* load outline coordinates into glyph */
2270         psh_glyph_load_points( glyph, dimension );
2271 
2272         /* compute local extrema */
2273         psh_glyph_compute_extrema( glyph );
2274 
2275         /* compute aligned stem/hints positions */
2276         psh_hint_table_align_hints( &glyph->hint_tables[dimension],
2277                                     glyph->globals,
2278                                     dimension,
2279                                     glyph );
2280 
2281         /* find strong points, align them, then interpolate others */
2282         psh_glyph_find_strong_points( glyph, dimension );
2283         if ( dimension == 1 )
2284           psh_glyph_find_blue_points( &globals->blues, glyph );
2285         psh_glyph_interpolate_strong_points( glyph, dimension );
2286         psh_glyph_interpolate_normal_points( glyph, dimension );
2287         psh_glyph_interpolate_other_points( glyph, dimension );
2288 
2289         /* save hinted coordinates back to outline */
2290         psh_glyph_save_points( glyph, dimension );
2291 
2292         if ( rescale )
2293           psh_globals_set_scale( glyph->globals,
2294                                  old_x_scale, old_y_scale, 0, 0 );
2295       }
2296     }
2297 
2298   Exit:
2299 
2300 #ifndef DEBUG_HINTER
2301     psh_glyph_done( glyph );
2302 #endif
2303 
2304     return error;
2305   }
2306 
2307 
2308 /* END */
2309