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1 /****************************************************************************
2  *
3  * ttsubpix.c
4  *
5  *   TrueType Subpixel Hinting.
6  *
7  * Copyright (C) 2010-2020 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 #include <freetype/internal/ftdebug.h>
19 #include <freetype/internal/ftcalc.h>
20 #include <freetype/internal/ftstream.h>
21 #include <freetype/internal/sfnt.h>
22 #include <freetype/tttags.h>
23 #include <freetype/ftoutln.h>
24 #include <freetype/ftdriver.h>
25 
26 #include "ttsubpix.h"
27 
28 
29 #if defined( TT_USE_BYTECODE_INTERPRETER )            && \
30     defined( TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY )
31 
32   /**************************************************************************
33    *
34    * These rules affect how the TT Interpreter does hinting, with the
35    * goal of doing subpixel hinting by (in general) ignoring x moves.
36    * Some of these rules are fixes that go above and beyond the
37    * stated techniques in the MS whitepaper on Cleartype, due to
38    * artifacts in many glyphs.  So, these rules make some glyphs render
39    * better than they do in the MS rasterizer.
40    *
41    * "" string or 0 int/char indicates to apply to all glyphs.
42    * "-" used as dummy placeholders, but any non-matching string works.
43    *
44    * Some of this could arguably be implemented in fontconfig, however:
45    *
46    * - Fontconfig can't set things on a glyph-by-glyph basis.
47    * - The tweaks that happen here are very low-level, from an average
48    *   user's point of view and are best implemented in the hinter.
49    *
50    * The goal is to make the subpixel hinting techniques as generalized
51    * as possible across all fonts to prevent the need for extra rules such
52    * as these.
53    *
54    * The rule structure is designed so that entirely new rules can easily
55    * be added when a new compatibility feature is discovered.
56    *
57    * The rule structures could also use some enhancement to handle ranges.
58    *
59    *     ****************** WORK IN PROGRESS *******************
60    */
61 
62   /* These are `classes' of fonts that can be grouped together and used in */
63   /* rules below.  A blank entry "" is required at the end of these!       */
64 #define FAMILY_CLASS_RULES_SIZE  7
65 
66   static const SPH_Font_Class  FAMILY_CLASS_Rules
67                                [FAMILY_CLASS_RULES_SIZE] =
68   {
69     { "MS Legacy Fonts",
70       { "Aharoni",
71         "Andale Mono",
72         "Andalus",
73         "Angsana New",
74         "AngsanaUPC",
75         "Arabic Transparent",
76         "Arial Black",
77         "Arial Narrow",
78         "Arial Unicode MS",
79         "Arial",
80         "Batang",
81         "Browallia New",
82         "BrowalliaUPC",
83         "Comic Sans MS",
84         "Cordia New",
85         "CordiaUPC",
86         "Courier New",
87         "DFKai-SB",
88         "David Transparent",
89         "David",
90         "DilleniaUPC",
91         "Estrangelo Edessa",
92         "EucrosiaUPC",
93         "FangSong_GB2312",
94         "Fixed Miriam Transparent",
95         "FrankRuehl",
96         "Franklin Gothic Medium",
97         "FreesiaUPC",
98         "Garamond",
99         "Gautami",
100         "Georgia",
101         "Gulim",
102         "Impact",
103         "IrisUPC",
104         "JasmineUPC",
105         "KaiTi_GB2312",
106         "KodchiangUPC",
107         "Latha",
108         "Levenim MT",
109         "LilyUPC",
110         "Lucida Console",
111         "Lucida Sans Unicode",
112         "MS Gothic",
113         "MS Mincho",
114         "MV Boli",
115         "Mangal",
116         "Marlett",
117         "Microsoft Sans Serif",
118         "Mingliu",
119         "Miriam Fixed",
120         "Miriam Transparent",
121         "Miriam",
122         "Narkisim",
123         "Palatino Linotype",
124         "Raavi",
125         "Rod Transparent",
126         "Rod",
127         "Shruti",
128         "SimHei",
129         "Simplified Arabic Fixed",
130         "Simplified Arabic",
131         "Simsun",
132         "Sylfaen",
133         "Symbol",
134         "Tahoma",
135         "Times New Roman",
136         "Traditional Arabic",
137         "Trebuchet MS",
138         "Tunga",
139         "Verdana",
140         "Webdings",
141         "Wingdings",
142         "",
143       },
144     },
145     { "Core MS Legacy Fonts",
146       { "Arial Black",
147         "Arial Narrow",
148         "Arial Unicode MS",
149         "Arial",
150         "Comic Sans MS",
151         "Courier New",
152         "Garamond",
153         "Georgia",
154         "Impact",
155         "Lucida Console",
156         "Lucida Sans Unicode",
157         "Microsoft Sans Serif",
158         "Palatino Linotype",
159         "Tahoma",
160         "Times New Roman",
161         "Trebuchet MS",
162         "Verdana",
163         "",
164       },
165     },
166     { "Apple Legacy Fonts",
167       { "Geneva",
168         "Times",
169         "Monaco",
170         "Century",
171         "Chalkboard",
172         "Lobster",
173         "Century Gothic",
174         "Optima",
175         "Lucida Grande",
176         "Gill Sans",
177         "Baskerville",
178         "Helvetica",
179         "Helvetica Neue",
180         "",
181       },
182     },
183     { "Legacy Sans Fonts",
184       { "Andale Mono",
185         "Arial Unicode MS",
186         "Arial",
187         "Century Gothic",
188         "Comic Sans MS",
189         "Franklin Gothic Medium",
190         "Geneva",
191         "Lucida Console",
192         "Lucida Grande",
193         "Lucida Sans Unicode",
194         "Lucida Sans Typewriter",
195         "Microsoft Sans Serif",
196         "Monaco",
197         "Tahoma",
198         "Trebuchet MS",
199         "Verdana",
200         "",
201       },
202     },
203 
204     { "Misc Legacy Fonts",
205       { "Dark Courier", "", }, },
206     { "Verdana Clones",
207       { "DejaVu Sans",
208         "Bitstream Vera Sans", "", }, },
209     { "Verdana and Clones",
210       { "DejaVu Sans",
211         "Bitstream Vera Sans",
212         "Verdana", "", }, },
213   };
214 
215 
216   /* Define this to force natural (i.e. not bitmap-compatible) widths.     */
217   /* The default leans strongly towards natural widths except for a few    */
218   /* legacy fonts where a selective combination produces nicer results.    */
219 /* #define FORCE_NATURAL_WIDTHS   */
220 
221 
222   /* Define `classes' of styles that can be grouped together and used in   */
223   /* rules below.  A blank entry "" is required at the end of these!       */
224 #define STYLE_CLASS_RULES_SIZE  5
225 
226   static const SPH_Font_Class  STYLE_CLASS_Rules
227                                [STYLE_CLASS_RULES_SIZE] =
228   {
229     { "Regular Class",
230       { "Regular",
231         "Book",
232         "Medium",
233         "Roman",
234         "Normal",
235         "",
236       },
237     },
238     { "Regular/Italic Class",
239       { "Regular",
240         "Book",
241         "Medium",
242         "Italic",
243         "Oblique",
244         "Roman",
245         "Normal",
246         "",
247       },
248     },
249     { "Bold/BoldItalic Class",
250       { "Bold",
251         "Bold Italic",
252         "Black",
253         "",
254       },
255     },
256     { "Bold/Italic/BoldItalic Class",
257       { "Bold",
258         "Bold Italic",
259         "Black",
260         "Italic",
261         "Oblique",
262         "",
263       },
264     },
265     { "Regular/Bold Class",
266       { "Regular",
267         "Book",
268         "Medium",
269         "Normal",
270         "Roman",
271         "Bold",
272         "Black",
273         "",
274       },
275     },
276   };
277 
278 
279   /* Force special legacy fixes for fonts.                                 */
280 #define COMPATIBILITY_MODE_RULES_SIZE  1
281 
282   static const SPH_TweakRule  COMPATIBILITY_MODE_Rules
283                               [COMPATIBILITY_MODE_RULES_SIZE] =
284   {
285     { "Verdana Clones", 0, "", 0 },
286   };
287 
288 
289   /* Don't do subpixel (ignore_x_mode) hinting; do normal hinting.         */
290 #define PIXEL_HINTING_RULES_SIZE  2
291 
292   static const SPH_TweakRule  PIXEL_HINTING_Rules
293                               [PIXEL_HINTING_RULES_SIZE] =
294   {
295     /* these characters are almost always safe */
296     { "Courier New", 12, "Italic", 'z' },
297     { "Courier New", 11, "Italic", 'z' },
298   };
299 
300 
301   /* Subpixel hinting ignores SHPIX rules on X.  Force SHPIX for these.    */
302 #define DO_SHPIX_RULES_SIZE  1
303 
304   static const SPH_TweakRule  DO_SHPIX_Rules
305                               [DO_SHPIX_RULES_SIZE] =
306   {
307     { "-", 0, "", 0 },
308   };
309 
310 
311   /* Skip Y moves that start with a point that is not on a Y pixel         */
312   /* boundary and don't move that point to a Y pixel boundary.             */
313 #define SKIP_NONPIXEL_Y_MOVES_RULES_SIZE  4
314 
315   static const SPH_TweakRule  SKIP_NONPIXEL_Y_MOVES_Rules
316                               [SKIP_NONPIXEL_Y_MOVES_RULES_SIZE] =
317   {
318     /* fix vwxyz thinness*/
319     { "Consolas", 0, "", 0 },
320     /* Fix thin middle stems */
321     { "Core MS Legacy Fonts", 0, "Regular", 0 },
322     /* Cyrillic small letter I */
323     { "Legacy Sans Fonts", 0, "", 0 },
324     /* Fix artifacts with some Regular & Bold */
325     { "Verdana Clones", 0, "", 0 },
326   };
327 
328 
329 #define SKIP_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE  1
330 
331   static const SPH_TweakRule  SKIP_NONPIXEL_Y_MOVES_Rules_Exceptions
332                               [SKIP_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE] =
333   {
334     /* Fixes < and > */
335     { "Courier New", 0, "Regular", 0 },
336   };
337 
338 
339   /* Skip Y moves that start with a point that is not on a Y pixel         */
340   /* boundary and don't move that point to a Y pixel boundary.             */
341 #define SKIP_NONPIXEL_Y_MOVES_DELTAP_RULES_SIZE  2
342 
343   static const SPH_TweakRule  SKIP_NONPIXEL_Y_MOVES_DELTAP_Rules
344                               [SKIP_NONPIXEL_Y_MOVES_DELTAP_RULES_SIZE] =
345   {
346     /* Maintain thickness of diagonal in 'N' */
347     { "Times New Roman", 0, "Regular/Bold Class", 'N' },
348     { "Georgia", 0, "Regular/Bold Class", 'N' },
349   };
350 
351 
352   /* Skip Y moves that move a point off a Y pixel boundary.                */
353 #define SKIP_OFFPIXEL_Y_MOVES_RULES_SIZE  1
354 
355   static const SPH_TweakRule  SKIP_OFFPIXEL_Y_MOVES_Rules
356                               [SKIP_OFFPIXEL_Y_MOVES_RULES_SIZE] =
357   {
358     { "-", 0, "", 0 },
359   };
360 
361 
362 #define SKIP_OFFPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE  1
363 
364   static const SPH_TweakRule  SKIP_OFFPIXEL_Y_MOVES_Rules_Exceptions
365                               [SKIP_OFFPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE] =
366   {
367     { "-", 0, "", 0 },
368   };
369 
370 
371   /* Round moves that don't move a point to a Y pixel boundary.            */
372 #define ROUND_NONPIXEL_Y_MOVES_RULES_SIZE  2
373 
374   static const SPH_TweakRule  ROUND_NONPIXEL_Y_MOVES_Rules
375                               [ROUND_NONPIXEL_Y_MOVES_RULES_SIZE] =
376   {
377     /* Droid font instructions don't snap Y to pixels */
378     { "Droid Sans", 0, "Regular/Italic Class", 0 },
379     { "Droid Sans Mono", 0, "", 0 },
380   };
381 
382 
383 #define ROUND_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE  1
384 
385   static const SPH_TweakRule  ROUND_NONPIXEL_Y_MOVES_Rules_Exceptions
386                               [ROUND_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE] =
387   {
388     { "-", 0, "", 0 },
389   };
390 
391 
392   /* Allow a Direct_Move along X freedom vector if matched.                */
393 #define ALLOW_X_DMOVE_RULES_SIZE  1
394 
395   static const SPH_TweakRule  ALLOW_X_DMOVE_Rules
396                               [ALLOW_X_DMOVE_RULES_SIZE] =
397   {
398     /* Fixes vanishing diagonal in 4 */
399     { "Verdana", 0, "Regular", '4' },
400   };
401 
402 
403   /* Return MS rasterizer version 35 if matched.                           */
404 #define RASTERIZER_35_RULES_SIZE  8
405 
406   static const SPH_TweakRule  RASTERIZER_35_Rules
407                               [RASTERIZER_35_RULES_SIZE] =
408   {
409     /* This seems to be the only way to make these look good */
410     { "Times New Roman", 0, "Regular", 'i' },
411     { "Times New Roman", 0, "Regular", 'j' },
412     { "Times New Roman", 0, "Regular", 'm' },
413     { "Times New Roman", 0, "Regular", 'r' },
414     { "Times New Roman", 0, "Regular", 'a' },
415     { "Times New Roman", 0, "Regular", 'n' },
416     { "Times New Roman", 0, "Regular", 'p' },
417     { "Times", 0, "", 0 },
418   };
419 
420 
421   /* Don't round to the subpixel grid.  Round to pixel grid.               */
422 #define NORMAL_ROUND_RULES_SIZE  1
423 
424   static const SPH_TweakRule  NORMAL_ROUND_Rules
425                               [NORMAL_ROUND_RULES_SIZE] =
426   {
427     /* Fix serif thickness for certain ppems */
428     /* Can probably be generalized somehow   */
429     { "Courier New", 0, "", 0 },
430   };
431 
432 
433   /* Skip IUP instructions if matched.                                     */
434 #define SKIP_IUP_RULES_SIZE  1
435 
436   static const SPH_TweakRule  SKIP_IUP_Rules
437                               [SKIP_IUP_RULES_SIZE] =
438   {
439     { "Arial", 13, "Regular", 'a' },
440   };
441 
442 
443   /* Skip MIAP Twilight hack if matched.                                   */
444 #define MIAP_HACK_RULES_SIZE  1
445 
446   static const SPH_TweakRule  MIAP_HACK_Rules
447                               [MIAP_HACK_RULES_SIZE] =
448   {
449     { "Geneva", 12, "", 0 },
450   };
451 
452 
453   /* Skip DELTAP instructions if matched.                                  */
454 #define ALWAYS_SKIP_DELTAP_RULES_SIZE  23
455 
456   static const SPH_TweakRule  ALWAYS_SKIP_DELTAP_Rules
457                               [ALWAYS_SKIP_DELTAP_RULES_SIZE] =
458   {
459     { "Georgia", 0, "Regular", 'k' },
460     /* fix various problems with e in different versions */
461     { "Trebuchet MS", 14, "Regular", 'e' },
462     { "Trebuchet MS", 13, "Regular", 'e' },
463     { "Trebuchet MS", 15, "Regular", 'e' },
464     { "Trebuchet MS", 0, "Italic", 'v' },
465     { "Trebuchet MS", 0, "Italic", 'w' },
466     { "Trebuchet MS", 0, "Regular", 'Y' },
467     { "Arial", 11, "Regular", 's' },
468     /* prevent problems with '3' and others */
469     { "Verdana", 10, "Regular", 0 },
470     { "Verdana", 9, "Regular", 0 },
471     /* Cyrillic small letter short I */
472     { "Legacy Sans Fonts", 0, "", 0x438 },
473     { "Legacy Sans Fonts", 0, "", 0x439 },
474     { "Arial", 10, "Regular", '6' },
475     { "Arial", 0, "Bold/BoldItalic Class", 'a' },
476     /* Make horizontal stems consistent with the rest */
477     { "Arial", 24, "Bold", 'a' },
478     { "Arial", 25, "Bold", 'a' },
479     { "Arial", 24, "Bold", 's' },
480     { "Arial", 25, "Bold", 's' },
481     { "Arial", 34, "Bold", 's' },
482     { "Arial", 35, "Bold", 's' },
483     { "Arial", 36, "Bold", 's' },
484     { "Arial", 25, "Regular", 's' },
485     { "Arial", 26, "Regular", 's' },
486   };
487 
488 
489   /* Always do DELTAP instructions if matched.                             */
490 #define ALWAYS_DO_DELTAP_RULES_SIZE  1
491 
492   static const SPH_TweakRule  ALWAYS_DO_DELTAP_Rules
493                               [ALWAYS_DO_DELTAP_RULES_SIZE] =
494   {
495     { "-", 0, "", 0 },
496   };
497 
498 
499   /* Don't allow ALIGNRP after IUP.                                        */
500 #define NO_ALIGNRP_AFTER_IUP_RULES_SIZE  1
501 
502   static const SPH_TweakRule  NO_ALIGNRP_AFTER_IUP_Rules
503                               [NO_ALIGNRP_AFTER_IUP_RULES_SIZE] =
504   {
505     /* Prevent creation of dents in outline */
506     { "-", 0, "", 0 },
507   };
508 
509 
510   /* Don't allow DELTAP after IUP.                                         */
511 #define NO_DELTAP_AFTER_IUP_RULES_SIZE  1
512 
513   static const SPH_TweakRule  NO_DELTAP_AFTER_IUP_Rules
514                               [NO_DELTAP_AFTER_IUP_RULES_SIZE] =
515   {
516     { "-", 0, "", 0 },
517   };
518 
519 
520   /* Don't allow CALL after IUP.                                           */
521 #define NO_CALL_AFTER_IUP_RULES_SIZE  1
522 
523   static const SPH_TweakRule  NO_CALL_AFTER_IUP_Rules
524                               [NO_CALL_AFTER_IUP_RULES_SIZE] =
525   {
526     /* Prevent creation of dents in outline */
527     { "-", 0, "", 0 },
528   };
529 
530 
531   /* De-embolden these glyphs slightly.                                    */
532 #define DEEMBOLDEN_RULES_SIZE  9
533 
534   static const SPH_TweakRule  DEEMBOLDEN_Rules
535                               [DEEMBOLDEN_RULES_SIZE] =
536   {
537     { "Courier New", 0, "Bold", 'A' },
538     { "Courier New", 0, "Bold", 'W' },
539     { "Courier New", 0, "Bold", 'w' },
540     { "Courier New", 0, "Bold", 'M' },
541     { "Courier New", 0, "Bold", 'X' },
542     { "Courier New", 0, "Bold", 'K' },
543     { "Courier New", 0, "Bold", 'x' },
544     { "Courier New", 0, "Bold", 'z' },
545     { "Courier New", 0, "Bold", 'v' },
546   };
547 
548 
549   /* Embolden these glyphs slightly.                                       */
550 #define EMBOLDEN_RULES_SIZE  2
551 
552   static const SPH_TweakRule  EMBOLDEN_Rules
553                               [EMBOLDEN_RULES_SIZE] =
554   {
555     { "Courier New", 0, "Regular", 0 },
556     { "Courier New", 0, "Italic", 0 },
557   };
558 
559 
560   /* This is a CVT hack that makes thick horizontal stems on 2, 5, 7       */
561   /* similar to Windows XP.                                                */
562 #define TIMES_NEW_ROMAN_HACK_RULES_SIZE  12
563 
564   static const SPH_TweakRule  TIMES_NEW_ROMAN_HACK_Rules
565                               [TIMES_NEW_ROMAN_HACK_RULES_SIZE] =
566   {
567     { "Times New Roman", 16, "Italic", '2' },
568     { "Times New Roman", 16, "Italic", '5' },
569     { "Times New Roman", 16, "Italic", '7' },
570     { "Times New Roman", 16, "Regular", '2' },
571     { "Times New Roman", 16, "Regular", '5' },
572     { "Times New Roman", 16, "Regular", '7' },
573     { "Times New Roman", 17, "Italic", '2' },
574     { "Times New Roman", 17, "Italic", '5' },
575     { "Times New Roman", 17, "Italic", '7' },
576     { "Times New Roman", 17, "Regular", '2' },
577     { "Times New Roman", 17, "Regular", '5' },
578     { "Times New Roman", 17, "Regular", '7' },
579   };
580 
581 
582   /* This fudges distance on 2 to get rid of the vanishing stem issue.     */
583   /* A real solution to this is certainly welcome.                         */
584 #define COURIER_NEW_2_HACK_RULES_SIZE  15
585 
586   static const SPH_TweakRule  COURIER_NEW_2_HACK_Rules
587                               [COURIER_NEW_2_HACK_RULES_SIZE] =
588   {
589     { "Courier New", 10, "Regular", '2' },
590     { "Courier New", 11, "Regular", '2' },
591     { "Courier New", 12, "Regular", '2' },
592     { "Courier New", 13, "Regular", '2' },
593     { "Courier New", 14, "Regular", '2' },
594     { "Courier New", 15, "Regular", '2' },
595     { "Courier New", 16, "Regular", '2' },
596     { "Courier New", 17, "Regular", '2' },
597     { "Courier New", 18, "Regular", '2' },
598     { "Courier New", 19, "Regular", '2' },
599     { "Courier New", 20, "Regular", '2' },
600     { "Courier New", 21, "Regular", '2' },
601     { "Courier New", 22, "Regular", '2' },
602     { "Courier New", 23, "Regular", '2' },
603     { "Courier New", 24, "Regular", '2' },
604   };
605 
606 
607 #ifndef FORCE_NATURAL_WIDTHS
608 
609   /* Use compatible widths with these glyphs.  Compatible widths is always */
610   /* on when doing B/W TrueType instructing, but is used selectively here, */
611   /* typically on glyphs with 3 or more vertical stems.                    */
612 #define COMPATIBLE_WIDTHS_RULES_SIZE  38
613 
614   static const SPH_TweakRule  COMPATIBLE_WIDTHS_Rules
615                               [COMPATIBLE_WIDTHS_RULES_SIZE] =
616   {
617     { "Arial Unicode MS", 12, "Regular Class", 'm' },
618     { "Arial Unicode MS", 14, "Regular Class", 'm' },
619     /* Cyrillic small letter sha */
620     { "Arial", 10, "Regular Class", 0x448 },
621     { "Arial", 11, "Regular Class", 'm' },
622     { "Arial", 12, "Regular Class", 'm' },
623     /* Cyrillic small letter sha */
624     { "Arial", 12, "Regular Class", 0x448 },
625     { "Arial", 13, "Regular Class", 0x448 },
626     { "Arial", 14, "Regular Class", 'm' },
627     /* Cyrillic small letter sha */
628     { "Arial", 14, "Regular Class", 0x448 },
629     { "Arial", 15, "Regular Class", 0x448 },
630     { "Arial", 17, "Regular Class", 'm' },
631     { "DejaVu Sans", 15, "Regular Class", 0 },
632     { "Microsoft Sans Serif", 11, "Regular Class", 0 },
633     { "Microsoft Sans Serif", 12, "Regular Class", 0 },
634     { "Segoe UI", 11, "Regular Class", 0 },
635     { "Monaco", 0, "Regular Class", 0 },
636     { "Segoe UI", 12, "Regular Class", 'm' },
637     { "Segoe UI", 14, "Regular Class", 'm' },
638     { "Tahoma", 11, "Regular Class", 0 },
639     { "Times New Roman", 16, "Regular Class", 'c' },
640     { "Times New Roman", 16, "Regular Class", 'm' },
641     { "Times New Roman", 16, "Regular Class", 'o' },
642     { "Times New Roman", 16, "Regular Class", 'w' },
643     { "Trebuchet MS", 11, "Regular Class", 0 },
644     { "Trebuchet MS", 12, "Regular Class", 0 },
645     { "Trebuchet MS", 14, "Regular Class", 0 },
646     { "Trebuchet MS", 15, "Regular Class", 0 },
647     { "Ubuntu", 12, "Regular Class", 'm' },
648     /* Cyrillic small letter sha */
649     { "Verdana", 10, "Regular Class", 0x448 },
650     { "Verdana", 11, "Regular Class", 0x448 },
651     { "Verdana and Clones", 12, "Regular Class", 'i' },
652     { "Verdana and Clones", 12, "Regular Class", 'j' },
653     { "Verdana and Clones", 12, "Regular Class", 'l' },
654     { "Verdana and Clones", 12, "Regular Class", 'm' },
655     { "Verdana and Clones", 13, "Regular Class", 'i' },
656     { "Verdana and Clones", 13, "Regular Class", 'j' },
657     { "Verdana and Clones", 13, "Regular Class", 'l' },
658     { "Verdana and Clones", 14, "Regular Class", 'm' },
659   };
660 
661 
662   /* Scaling slightly in the x-direction prior to hinting results in       */
663   /* more visually pleasing glyphs in certain cases.                       */
664   /* This sometimes needs to be coordinated with compatible width rules.   */
665   /* A value of 1000 corresponds to a scaled value of 1.0.                 */
666 
667 #define X_SCALING_RULES_SIZE  50
668 
669   static const SPH_ScaleRule  X_SCALING_Rules[X_SCALING_RULES_SIZE] =
670   {
671     { "DejaVu Sans", 12, "Regular Class", 'm', 950 },
672     { "Verdana and Clones", 12, "Regular Class", 'a', 1100 },
673     { "Verdana and Clones", 13, "Regular Class", 'a', 1050 },
674     { "Arial", 11, "Regular Class", 'm', 975 },
675     { "Arial", 12, "Regular Class", 'm', 1050 },
676     /* Cyrillic small letter el */
677     { "Arial", 13, "Regular Class", 0x43B, 950 },
678     { "Arial", 13, "Regular Class", 'o', 950 },
679     { "Arial", 13, "Regular Class", 'e', 950 },
680     { "Arial", 14, "Regular Class", 'm', 950 },
681     /* Cyrillic small letter el */
682     { "Arial", 15, "Regular Class", 0x43B, 925 },
683     { "Bitstream Vera Sans", 10, "Regular/Italic Class", 0, 1100 },
684     { "Bitstream Vera Sans", 12, "Regular/Italic Class", 0, 1050 },
685     { "Bitstream Vera Sans", 16, "Regular Class", 0, 1050 },
686     { "Bitstream Vera Sans", 9, "Regular/Italic Class", 0, 1050 },
687     { "DejaVu Sans", 12, "Regular Class", 'l', 975 },
688     { "DejaVu Sans", 12, "Regular Class", 'i', 975 },
689     { "DejaVu Sans", 12, "Regular Class", 'j', 975 },
690     { "DejaVu Sans", 13, "Regular Class", 'l', 950 },
691     { "DejaVu Sans", 13, "Regular Class", 'i', 950 },
692     { "DejaVu Sans", 13, "Regular Class", 'j', 950 },
693     { "DejaVu Sans", 10, "Regular/Italic Class", 0, 1100 },
694     { "DejaVu Sans", 12, "Regular/Italic Class", 0, 1050 },
695     { "Georgia", 10, "", 0, 1050 },
696     { "Georgia", 11, "", 0, 1100 },
697     { "Georgia", 12, "", 0, 1025 },
698     { "Georgia", 13, "", 0, 1050 },
699     { "Georgia", 16, "", 0, 1050 },
700     { "Georgia", 17, "", 0, 1030 },
701     { "Liberation Sans", 12, "Regular Class", 'm', 1100 },
702     { "Lucida Grande", 11, "Regular Class", 'm', 1100 },
703     { "Microsoft Sans Serif", 11, "Regular Class", 'm', 950 },
704     { "Microsoft Sans Serif", 12, "Regular Class", 'm', 1050 },
705     { "Segoe UI", 12, "Regular Class", 'H', 1050 },
706     { "Segoe UI", 12, "Regular Class", 'm', 1050 },
707     { "Segoe UI", 14, "Regular Class", 'm', 1050 },
708     { "Tahoma", 11, "Regular Class", 'i', 975 },
709     { "Tahoma", 11, "Regular Class", 'l', 975 },
710     { "Tahoma", 11, "Regular Class", 'j', 900 },
711     { "Tahoma", 11, "Regular Class", 'm', 918 },
712     { "Verdana", 10, "Regular/Italic Class", 0, 1100 },
713     { "Verdana", 12, "Regular Class", 'm', 975 },
714     { "Verdana", 12, "Regular/Italic Class", 0, 1050 },
715     { "Verdana", 13, "Regular/Italic Class", 'i', 950 },
716     { "Verdana", 13, "Regular/Italic Class", 'j', 950 },
717     { "Verdana", 13, "Regular/Italic Class", 'l', 950 },
718     { "Verdana", 16, "Regular Class", 0, 1050 },
719     { "Verdana", 9, "Regular/Italic Class", 0, 1050 },
720     { "Times New Roman", 16, "Regular Class", 'm', 918 },
721     { "Trebuchet MS", 11, "Regular Class", 'm', 800 },
722     { "Trebuchet MS", 12, "Regular Class", 'm', 800 },
723   };
724 
725 #else
726 
727 #define COMPATIBLE_WIDTHS_RULES_SIZE  1
728 
729   static const SPH_TweakRule  COMPATIBLE_WIDTHS_Rules
730                               [COMPATIBLE_WIDTHS_RULES_SIZE] =
731   {
732     { "-", 0, "", 0 },
733   };
734 
735 
736 #define X_SCALING_RULES_SIZE  1
737 
738   static const SPH_ScaleRule  X_SCALING_Rules
739                               [X_SCALING_RULES_SIZE] =
740   {
741     { "-", 0, "", 0, 1000 },
742   };
743 
744 #endif /* FORCE_NATURAL_WIDTHS */
745 
746 
747   static FT_Bool
is_member_of_family_class(const FT_String * detected_font_name,const FT_String * rule_font_name)748   is_member_of_family_class( const FT_String*  detected_font_name,
749                              const FT_String*  rule_font_name )
750   {
751     FT_UInt  i, j;
752 
753 
754     /* Does font name match rule family? */
755     if ( ft_strcmp( detected_font_name, rule_font_name ) == 0 )
756       return TRUE;
757 
758     /* Is font name a wildcard ""? */
759     if ( ft_strcmp( rule_font_name, "" ) == 0 )
760       return TRUE;
761 
762     /* Is font name contained in a class list? */
763     for ( i = 0; i < FAMILY_CLASS_RULES_SIZE; i++ )
764     {
765       if ( ft_strcmp( FAMILY_CLASS_Rules[i].name, rule_font_name ) == 0 )
766       {
767         for ( j = 0; j < SPH_MAX_CLASS_MEMBERS; j++ )
768         {
769           if ( ft_strcmp( FAMILY_CLASS_Rules[i].member[j], "" ) == 0 )
770             continue;
771           if ( ft_strcmp( FAMILY_CLASS_Rules[i].member[j],
772                           detected_font_name ) == 0 )
773             return TRUE;
774         }
775       }
776     }
777 
778     return FALSE;
779   }
780 
781 
782   static FT_Bool
is_member_of_style_class(const FT_String * detected_font_style,const FT_String * rule_font_style)783   is_member_of_style_class( const FT_String*  detected_font_style,
784                             const FT_String*  rule_font_style )
785   {
786     FT_UInt  i, j;
787 
788 
789     /* Does font style match rule style? */
790     if ( ft_strcmp( detected_font_style, rule_font_style ) == 0 )
791       return TRUE;
792 
793     /* Is font style a wildcard ""? */
794     if ( ft_strcmp( rule_font_style, "" ) == 0 )
795       return TRUE;
796 
797     /* Is font style contained in a class list? */
798     for ( i = 0; i < STYLE_CLASS_RULES_SIZE; i++ )
799     {
800       if ( ft_strcmp( STYLE_CLASS_Rules[i].name, rule_font_style ) == 0 )
801       {
802         for ( j = 0; j < SPH_MAX_CLASS_MEMBERS; j++ )
803         {
804           if ( ft_strcmp( STYLE_CLASS_Rules[i].member[j], "" ) == 0 )
805             continue;
806           if ( ft_strcmp( STYLE_CLASS_Rules[i].member[j],
807                           detected_font_style ) == 0 )
808             return TRUE;
809         }
810       }
811     }
812 
813     return FALSE;
814   }
815 
816 
817   FT_LOCAL_DEF( FT_Bool )
sph_test_tweak(TT_Face face,const FT_String * family,FT_UInt ppem,const FT_String * style,FT_UInt glyph_index,const SPH_TweakRule * rule,FT_UInt num_rules)818   sph_test_tweak( TT_Face               face,
819                   const FT_String*      family,
820                   FT_UInt               ppem,
821                   const FT_String*      style,
822                   FT_UInt               glyph_index,
823                   const SPH_TweakRule*  rule,
824                   FT_UInt               num_rules )
825   {
826     FT_UInt  i;
827 
828 
829     /* rule checks may be able to be optimized further */
830     for ( i = 0; i < num_rules; i++ )
831     {
832       if ( family                                                   &&
833            ( is_member_of_family_class ( family, rule[i].family ) ) )
834         if ( rule[i].ppem == 0    ||
835              rule[i].ppem == ppem )
836           if ( style                                             &&
837                is_member_of_style_class ( style, rule[i].style ) )
838             if ( rule[i].glyph == 0                                ||
839                  FT_Get_Char_Index( (FT_Face)face,
840                                     rule[i].glyph ) == glyph_index )
841         return TRUE;
842     }
843 
844     return FALSE;
845   }
846 
847 
848   static FT_UInt
scale_test_tweak(TT_Face face,const FT_String * family,FT_UInt ppem,const FT_String * style,FT_UInt glyph_index,const SPH_ScaleRule * rule,FT_UInt num_rules)849   scale_test_tweak( TT_Face               face,
850                     const FT_String*      family,
851                     FT_UInt               ppem,
852                     const FT_String*      style,
853                     FT_UInt               glyph_index,
854                     const SPH_ScaleRule*  rule,
855                     FT_UInt               num_rules )
856   {
857     FT_UInt  i;
858 
859 
860     /* rule checks may be able to be optimized further */
861     for ( i = 0; i < num_rules; i++ )
862     {
863       if ( family                                                   &&
864            ( is_member_of_family_class ( family, rule[i].family ) ) )
865         if ( rule[i].ppem == 0    ||
866              rule[i].ppem == ppem )
867           if ( style                                            &&
868                is_member_of_style_class( style, rule[i].style ) )
869             if ( rule[i].glyph == 0                                ||
870                  FT_Get_Char_Index( (FT_Face)face,
871                                     rule[i].glyph ) == glyph_index )
872         return rule[i].scale;
873     }
874 
875     return 1000;
876   }
877 
878 
879   FT_LOCAL_DEF( FT_UInt )
sph_test_tweak_x_scaling(TT_Face face,const FT_String * family,FT_UInt ppem,const FT_String * style,FT_UInt glyph_index)880   sph_test_tweak_x_scaling( TT_Face           face,
881                             const FT_String*  family,
882                             FT_UInt           ppem,
883                             const FT_String*  style,
884                             FT_UInt           glyph_index )
885   {
886     return scale_test_tweak( face, family, ppem, style, glyph_index,
887                              X_SCALING_Rules, X_SCALING_RULES_SIZE );
888   }
889 
890 
891 #define TWEAK_RULES( x )                                       \
892   if ( sph_test_tweak( face, family, ppem, style, glyph_index, \
893                        x##_Rules, x##_RULES_SIZE ) )           \
894     loader->exec->sph_tweak_flags |= SPH_TWEAK_##x;
895 
896 #define TWEAK_RULES_EXCEPTIONS( x )                                        \
897   if ( sph_test_tweak( face, family, ppem, style, glyph_index,             \
898                        x##_Rules_Exceptions, x##_RULES_EXCEPTIONS_SIZE ) ) \
899     loader->exec->sph_tweak_flags &= ~SPH_TWEAK_##x;
900 
901 
902   FT_LOCAL_DEF( void )
sph_set_tweaks(TT_Loader loader,FT_UInt glyph_index)903   sph_set_tweaks( TT_Loader  loader,
904                   FT_UInt    glyph_index )
905   {
906     TT_Face     face   = loader->face;
907     FT_String*  family = face->root.family_name;
908     FT_UInt     ppem   = loader->size->metrics->x_ppem;
909     FT_String*  style  = face->root.style_name;
910 
911 
912     /* don't apply rules if style isn't set */
913     if ( !face->root.style_name )
914       return;
915 
916 #ifdef SPH_DEBUG_MORE_VERBOSE
917     printf( "%s,%d,%s,%c=%d ",
918             family, ppem, style, glyph_index, glyph_index );
919 #endif
920 
921     TWEAK_RULES( PIXEL_HINTING );
922 
923     if ( loader->exec->sph_tweak_flags & SPH_TWEAK_PIXEL_HINTING )
924     {
925       loader->exec->ignore_x_mode = FALSE;
926       return;
927     }
928 
929     TWEAK_RULES( ALLOW_X_DMOVE );
930     TWEAK_RULES( ALWAYS_DO_DELTAP );
931     TWEAK_RULES( ALWAYS_SKIP_DELTAP );
932     TWEAK_RULES( DEEMBOLDEN );
933     TWEAK_RULES( DO_SHPIX );
934     TWEAK_RULES( EMBOLDEN );
935     TWEAK_RULES( MIAP_HACK );
936     TWEAK_RULES( NORMAL_ROUND );
937     TWEAK_RULES( NO_ALIGNRP_AFTER_IUP );
938     TWEAK_RULES( NO_CALL_AFTER_IUP );
939     TWEAK_RULES( NO_DELTAP_AFTER_IUP );
940     TWEAK_RULES( RASTERIZER_35 );
941     TWEAK_RULES( SKIP_IUP );
942 
943     TWEAK_RULES( SKIP_OFFPIXEL_Y_MOVES );
944     TWEAK_RULES_EXCEPTIONS( SKIP_OFFPIXEL_Y_MOVES );
945 
946     TWEAK_RULES( SKIP_NONPIXEL_Y_MOVES_DELTAP );
947 
948     TWEAK_RULES( SKIP_NONPIXEL_Y_MOVES );
949     TWEAK_RULES_EXCEPTIONS( SKIP_NONPIXEL_Y_MOVES );
950 
951     TWEAK_RULES( ROUND_NONPIXEL_Y_MOVES );
952     TWEAK_RULES_EXCEPTIONS( ROUND_NONPIXEL_Y_MOVES );
953 
954     if ( loader->exec->sph_tweak_flags & SPH_TWEAK_RASTERIZER_35 )
955     {
956       if ( loader->exec->rasterizer_version != TT_INTERPRETER_VERSION_35 )
957       {
958         loader->exec->rasterizer_version = TT_INTERPRETER_VERSION_35;
959         loader->exec->size->cvt_ready    = -1;
960 
961         tt_size_ready_bytecode(
962           loader->exec->size,
963           FT_BOOL( loader->load_flags & FT_LOAD_PEDANTIC ) );
964       }
965       else
966         loader->exec->rasterizer_version = TT_INTERPRETER_VERSION_35;
967     }
968     else
969     {
970       if ( loader->exec->rasterizer_version  !=
971            SPH_OPTION_SET_RASTERIZER_VERSION )
972       {
973         loader->exec->rasterizer_version = SPH_OPTION_SET_RASTERIZER_VERSION;
974         loader->exec->size->cvt_ready    = -1;
975 
976         tt_size_ready_bytecode(
977           loader->exec->size,
978           FT_BOOL( loader->load_flags & FT_LOAD_PEDANTIC ) );
979       }
980       else
981         loader->exec->rasterizer_version = SPH_OPTION_SET_RASTERIZER_VERSION;
982     }
983 
984     if ( IS_HINTED( loader->load_flags ) )
985     {
986       TWEAK_RULES( TIMES_NEW_ROMAN_HACK );
987       TWEAK_RULES( COURIER_NEW_2_HACK );
988     }
989 
990     if ( sph_test_tweak( face, family, ppem, style, glyph_index,
991            COMPATIBILITY_MODE_Rules, COMPATIBILITY_MODE_RULES_SIZE ) )
992       loader->exec->face->sph_compatibility_mode = TRUE;
993 
994 
995     if ( IS_HINTED( loader->load_flags ) )
996     {
997       if ( sph_test_tweak( face, family, ppem, style, glyph_index,
998              COMPATIBLE_WIDTHS_Rules, COMPATIBLE_WIDTHS_RULES_SIZE ) )
999         loader->exec->compatible_widths |= TRUE;
1000     }
1001   }
1002 
1003 #else /* !(TT_USE_BYTECODE_INTERPRETER &&          */
1004       /*   TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY) */
1005 
1006   /* ANSI C doesn't like empty source files */
1007   typedef int  _tt_subpix_dummy;
1008 
1009 #endif /* !(TT_USE_BYTECODE_INTERPRETER &&          */
1010        /*   TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY) */
1011 
1012 
1013 /* END */
1014