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1 /****************************************************************************
2  *
3  * ttsubpix.c
4  *
5  *   TrueType Subpixel Hinting.
6  *
7  * Copyright 2010-2018 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 <ft2build.h>
19 #include FT_INTERNAL_DEBUG_H
20 #include FT_INTERNAL_CALC_H
21 #include FT_INTERNAL_STREAM_H
22 #include FT_INTERNAL_SFNT_H
23 #include FT_TRUETYPE_TAGS_H
24 #include FT_OUTLINE_H
25 #include FT_DRIVER_H
26 
27 #include "ttsubpix.h"
28 
29 
30 #if defined( TT_USE_BYTECODE_INTERPRETER )            && \
31     defined( TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY )
32 
33   /**************************************************************************
34    *
35    * These rules affect how the TT Interpreter does hinting, with the
36    * goal of doing subpixel hinting by (in general) ignoring x moves.
37    * Some of these rules are fixes that go above and beyond the
38    * stated techniques in the MS whitepaper on Cleartype, due to
39    * artifacts in many glyphs.  So, these rules make some glyphs render
40    * better than they do in the MS rasterizer.
41    *
42    * "" string or 0 int/char indicates to apply to all glyphs.
43    * "-" used as dummy placeholders, but any non-matching string works.
44    *
45    * Some of this could arguably be implemented in fontconfig, however:
46    *
47    * - Fontconfig can't set things on a glyph-by-glyph basis.
48    * - The tweaks that happen here are very low-level, from an average
49    *   user's point of view and are best implemented in the hinter.
50    *
51    * The goal is to make the subpixel hinting techniques as generalized
52    * as possible across all fonts to prevent the need for extra rules such
53    * as these.
54    *
55    * The rule structure is designed so that entirely new rules can easily
56    * be added when a new compatibility feature is discovered.
57    *
58    * The rule structures could also use some enhancement to handle ranges.
59    *
60    *     ****************** WORK IN PROGRESS *******************
61    */
62 
63   /* These are `classes' of fonts that can be grouped together and used in */
64   /* rules below.  A blank entry "" is required at the end of these!       */
65 #define FAMILY_CLASS_RULES_SIZE  7
66 
67   static const SPH_Font_Class  FAMILY_CLASS_Rules
68                                [FAMILY_CLASS_RULES_SIZE] =
69   {
70     { "MS Legacy Fonts",
71       { "Aharoni",
72         "Andale Mono",
73         "Andalus",
74         "Angsana New",
75         "AngsanaUPC",
76         "Arabic Transparent",
77         "Arial Black",
78         "Arial Narrow",
79         "Arial Unicode MS",
80         "Arial",
81         "Batang",
82         "Browallia New",
83         "BrowalliaUPC",
84         "Comic Sans MS",
85         "Cordia New",
86         "CordiaUPC",
87         "Courier New",
88         "DFKai-SB",
89         "David Transparent",
90         "David",
91         "DilleniaUPC",
92         "Estrangelo Edessa",
93         "EucrosiaUPC",
94         "FangSong_GB2312",
95         "Fixed Miriam Transparent",
96         "FrankRuehl",
97         "Franklin Gothic Medium",
98         "FreesiaUPC",
99         "Garamond",
100         "Gautami",
101         "Georgia",
102         "Gulim",
103         "Impact",
104         "IrisUPC",
105         "JasmineUPC",
106         "KaiTi_GB2312",
107         "KodchiangUPC",
108         "Latha",
109         "Levenim MT",
110         "LilyUPC",
111         "Lucida Console",
112         "Lucida Sans Unicode",
113         "MS Gothic",
114         "MS Mincho",
115         "MV Boli",
116         "Mangal",
117         "Marlett",
118         "Microsoft Sans Serif",
119         "Mingliu",
120         "Miriam Fixed",
121         "Miriam Transparent",
122         "Miriam",
123         "Narkisim",
124         "Palatino Linotype",
125         "Raavi",
126         "Rod Transparent",
127         "Rod",
128         "Shruti",
129         "SimHei",
130         "Simplified Arabic Fixed",
131         "Simplified Arabic",
132         "Simsun",
133         "Sylfaen",
134         "Symbol",
135         "Tahoma",
136         "Times New Roman",
137         "Traditional Arabic",
138         "Trebuchet MS",
139         "Tunga",
140         "Verdana",
141         "Webdings",
142         "Wingdings",
143         "",
144       },
145     },
146     { "Core MS Legacy Fonts",
147       { "Arial Black",
148         "Arial Narrow",
149         "Arial Unicode MS",
150         "Arial",
151         "Comic Sans MS",
152         "Courier New",
153         "Garamond",
154         "Georgia",
155         "Impact",
156         "Lucida Console",
157         "Lucida Sans Unicode",
158         "Microsoft Sans Serif",
159         "Palatino Linotype",
160         "Tahoma",
161         "Times New Roman",
162         "Trebuchet MS",
163         "Verdana",
164         "",
165       },
166     },
167     { "Apple Legacy Fonts",
168       { "Geneva",
169         "Times",
170         "Monaco",
171         "Century",
172         "Chalkboard",
173         "Lobster",
174         "Century Gothic",
175         "Optima",
176         "Lucida Grande",
177         "Gill Sans",
178         "Baskerville",
179         "Helvetica",
180         "Helvetica Neue",
181         "",
182       },
183     },
184     { "Legacy Sans Fonts",
185       { "Andale Mono",
186         "Arial Unicode MS",
187         "Arial",
188         "Century Gothic",
189         "Comic Sans MS",
190         "Franklin Gothic Medium",
191         "Geneva",
192         "Lucida Console",
193         "Lucida Grande",
194         "Lucida Sans Unicode",
195         "Lucida Sans Typewriter",
196         "Microsoft Sans Serif",
197         "Monaco",
198         "Tahoma",
199         "Trebuchet MS",
200         "Verdana",
201         "",
202       },
203     },
204 
205     { "Misc Legacy Fonts",
206       { "Dark Courier", "", }, },
207     { "Verdana Clones",
208       { "DejaVu Sans",
209         "Bitstream Vera Sans", "", }, },
210     { "Verdana and Clones",
211       { "DejaVu Sans",
212         "Bitstream Vera Sans",
213         "Verdana", "", }, },
214   };
215 
216 
217   /* Define this to force natural (i.e. not bitmap-compatible) widths.     */
218   /* The default leans strongly towards natural widths except for a few    */
219   /* legacy fonts where a selective combination produces nicer results.    */
220 /* #define FORCE_NATURAL_WIDTHS   */
221 
222 
223   /* Define `classes' of styles that can be grouped together and used in   */
224   /* rules below.  A blank entry "" is required at the end of these!       */
225 #define STYLE_CLASS_RULES_SIZE  5
226 
227   static const SPH_Font_Class  STYLE_CLASS_Rules
228                                [STYLE_CLASS_RULES_SIZE] =
229   {
230     { "Regular Class",
231       { "Regular",
232         "Book",
233         "Medium",
234         "Roman",
235         "Normal",
236         "",
237       },
238     },
239     { "Regular/Italic Class",
240       { "Regular",
241         "Book",
242         "Medium",
243         "Italic",
244         "Oblique",
245         "Roman",
246         "Normal",
247         "",
248       },
249     },
250     { "Bold/BoldItalic Class",
251       { "Bold",
252         "Bold Italic",
253         "Black",
254         "",
255       },
256     },
257     { "Bold/Italic/BoldItalic Class",
258       { "Bold",
259         "Bold Italic",
260         "Black",
261         "Italic",
262         "Oblique",
263         "",
264       },
265     },
266     { "Regular/Bold Class",
267       { "Regular",
268         "Book",
269         "Medium",
270         "Normal",
271         "Roman",
272         "Bold",
273         "Black",
274         "",
275       },
276     },
277   };
278 
279 
280   /* Force special legacy fixes for fonts.                                 */
281 #define COMPATIBILITY_MODE_RULES_SIZE  1
282 
283   static const SPH_TweakRule  COMPATIBILITY_MODE_Rules
284                               [COMPATIBILITY_MODE_RULES_SIZE] =
285   {
286     { "Verdana Clones", 0, "", 0 },
287   };
288 
289 
290   /* Don't do subpixel (ignore_x_mode) hinting; do normal hinting.         */
291 #define PIXEL_HINTING_RULES_SIZE  2
292 
293   static const SPH_TweakRule  PIXEL_HINTING_Rules
294                               [PIXEL_HINTING_RULES_SIZE] =
295   {
296     /* these characters are almost always safe */
297     { "Courier New", 12, "Italic", 'z' },
298     { "Courier New", 11, "Italic", 'z' },
299   };
300 
301 
302   /* Subpixel hinting ignores SHPIX rules on X.  Force SHPIX for these.    */
303 #define DO_SHPIX_RULES_SIZE  1
304 
305   static const SPH_TweakRule  DO_SHPIX_Rules
306                               [DO_SHPIX_RULES_SIZE] =
307   {
308     { "-", 0, "", 0 },
309   };
310 
311 
312   /* Skip Y moves that start with a point that is not on a Y pixel         */
313   /* boundary and don't move that point to a Y pixel boundary.             */
314 #define SKIP_NONPIXEL_Y_MOVES_RULES_SIZE  4
315 
316   static const SPH_TweakRule  SKIP_NONPIXEL_Y_MOVES_Rules
317                               [SKIP_NONPIXEL_Y_MOVES_RULES_SIZE] =
318   {
319     /* fix vwxyz thinness*/
320     { "Consolas", 0, "", 0 },
321     /* Fix thin middle stems */
322     { "Core MS Legacy Fonts", 0, "Regular", 0 },
323     /* Cyrillic small letter I */
324     { "Legacy Sans Fonts", 0, "", 0 },
325     /* Fix artifacts with some Regular & Bold */
326     { "Verdana Clones", 0, "", 0 },
327   };
328 
329 
330 #define SKIP_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE  1
331 
332   static const SPH_TweakRule  SKIP_NONPIXEL_Y_MOVES_Rules_Exceptions
333                               [SKIP_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE] =
334   {
335     /* Fixes < and > */
336     { "Courier New", 0, "Regular", 0 },
337   };
338 
339 
340   /* Skip Y moves that start with a point that is not on a Y pixel         */
341   /* boundary and don't move that point to a Y pixel boundary.             */
342 #define SKIP_NONPIXEL_Y_MOVES_DELTAP_RULES_SIZE  2
343 
344   static const SPH_TweakRule  SKIP_NONPIXEL_Y_MOVES_DELTAP_Rules
345                               [SKIP_NONPIXEL_Y_MOVES_DELTAP_RULES_SIZE] =
346   {
347     /* Maintain thickness of diagonal in 'N' */
348     { "Times New Roman", 0, "Regular/Bold Class", 'N' },
349     { "Georgia", 0, "Regular/Bold Class", 'N' },
350   };
351 
352 
353   /* Skip Y moves that move a point off a Y pixel boundary.                */
354 #define SKIP_OFFPIXEL_Y_MOVES_RULES_SIZE  1
355 
356   static const SPH_TweakRule  SKIP_OFFPIXEL_Y_MOVES_Rules
357                               [SKIP_OFFPIXEL_Y_MOVES_RULES_SIZE] =
358   {
359     { "-", 0, "", 0 },
360   };
361 
362 
363 #define SKIP_OFFPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE  1
364 
365   static const SPH_TweakRule  SKIP_OFFPIXEL_Y_MOVES_Rules_Exceptions
366                               [SKIP_OFFPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE] =
367   {
368     { "-", 0, "", 0 },
369   };
370 
371 
372   /* Round moves that don't move a point to a Y pixel boundary.            */
373 #define ROUND_NONPIXEL_Y_MOVES_RULES_SIZE  2
374 
375   static const SPH_TweakRule  ROUND_NONPIXEL_Y_MOVES_Rules
376                               [ROUND_NONPIXEL_Y_MOVES_RULES_SIZE] =
377   {
378     /* Droid font instructions don't snap Y to pixels */
379     { "Droid Sans", 0, "Regular/Italic Class", 0 },
380     { "Droid Sans Mono", 0, "", 0 },
381   };
382 
383 
384 #define ROUND_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE  1
385 
386   static const SPH_TweakRule  ROUND_NONPIXEL_Y_MOVES_Rules_Exceptions
387                               [ROUND_NONPIXEL_Y_MOVES_RULES_EXCEPTIONS_SIZE] =
388   {
389     { "-", 0, "", 0 },
390   };
391 
392 
393   /* Allow a Direct_Move along X freedom vector if matched.                */
394 #define ALLOW_X_DMOVE_RULES_SIZE  1
395 
396   static const SPH_TweakRule  ALLOW_X_DMOVE_Rules
397                               [ALLOW_X_DMOVE_RULES_SIZE] =
398   {
399     /* Fixes vanishing diagonal in 4 */
400     { "Verdana", 0, "Regular", '4' },
401   };
402 
403 
404   /* Return MS rasterizer version 35 if matched.                           */
405 #define RASTERIZER_35_RULES_SIZE  8
406 
407   static const SPH_TweakRule  RASTERIZER_35_Rules
408                               [RASTERIZER_35_RULES_SIZE] =
409   {
410     /* This seems to be the only way to make these look good */
411     { "Times New Roman", 0, "Regular", 'i' },
412     { "Times New Roman", 0, "Regular", 'j' },
413     { "Times New Roman", 0, "Regular", 'm' },
414     { "Times New Roman", 0, "Regular", 'r' },
415     { "Times New Roman", 0, "Regular", 'a' },
416     { "Times New Roman", 0, "Regular", 'n' },
417     { "Times New Roman", 0, "Regular", 'p' },
418     { "Times", 0, "", 0 },
419   };
420 
421 
422   /* Don't round to the subpixel grid.  Round to pixel grid.               */
423 #define NORMAL_ROUND_RULES_SIZE  1
424 
425   static const SPH_TweakRule  NORMAL_ROUND_Rules
426                               [NORMAL_ROUND_RULES_SIZE] =
427   {
428     /* Fix serif thickness for certain ppems */
429     /* Can probably be generalized somehow   */
430     { "Courier New", 0, "", 0 },
431   };
432 
433 
434   /* Skip IUP instructions if matched.                                     */
435 #define SKIP_IUP_RULES_SIZE  1
436 
437   static const SPH_TweakRule  SKIP_IUP_Rules
438                               [SKIP_IUP_RULES_SIZE] =
439   {
440     { "Arial", 13, "Regular", 'a' },
441   };
442 
443 
444   /* Skip MIAP Twilight hack if matched.                                   */
445 #define MIAP_HACK_RULES_SIZE  1
446 
447   static const SPH_TweakRule  MIAP_HACK_Rules
448                               [MIAP_HACK_RULES_SIZE] =
449   {
450     { "Geneva", 12, "", 0 },
451   };
452 
453 
454   /* Skip DELTAP instructions if matched.                                  */
455 #define ALWAYS_SKIP_DELTAP_RULES_SIZE  23
456 
457   static const SPH_TweakRule  ALWAYS_SKIP_DELTAP_Rules
458                               [ALWAYS_SKIP_DELTAP_RULES_SIZE] =
459   {
460     { "Georgia", 0, "Regular", 'k' },
461     /* fix various problems with e in different versions */
462     { "Trebuchet MS", 14, "Regular", 'e' },
463     { "Trebuchet MS", 13, "Regular", 'e' },
464     { "Trebuchet MS", 15, "Regular", 'e' },
465     { "Trebuchet MS", 0, "Italic", 'v' },
466     { "Trebuchet MS", 0, "Italic", 'w' },
467     { "Trebuchet MS", 0, "Regular", 'Y' },
468     { "Arial", 11, "Regular", 's' },
469     /* prevent problems with '3' and others */
470     { "Verdana", 10, "Regular", 0 },
471     { "Verdana", 9, "Regular", 0 },
472     /* Cyrillic small letter short I */
473     { "Legacy Sans Fonts", 0, "", 0x438 },
474     { "Legacy Sans Fonts", 0, "", 0x439 },
475     { "Arial", 10, "Regular", '6' },
476     { "Arial", 0, "Bold/BoldItalic Class", 'a' },
477     /* Make horizontal stems consistent with the rest */
478     { "Arial", 24, "Bold", 'a' },
479     { "Arial", 25, "Bold", 'a' },
480     { "Arial", 24, "Bold", 's' },
481     { "Arial", 25, "Bold", 's' },
482     { "Arial", 34, "Bold", 's' },
483     { "Arial", 35, "Bold", 's' },
484     { "Arial", 36, "Bold", 's' },
485     { "Arial", 25, "Regular", 's' },
486     { "Arial", 26, "Regular", 's' },
487   };
488 
489 
490   /* Always do DELTAP instructions if matched.                             */
491 #define ALWAYS_DO_DELTAP_RULES_SIZE  1
492 
493   static const SPH_TweakRule  ALWAYS_DO_DELTAP_Rules
494                               [ALWAYS_DO_DELTAP_RULES_SIZE] =
495   {
496     { "-", 0, "", 0 },
497   };
498 
499 
500   /* Don't allow ALIGNRP after IUP.                                        */
501 #define NO_ALIGNRP_AFTER_IUP_RULES_SIZE  1
502 
503   static const SPH_TweakRule  NO_ALIGNRP_AFTER_IUP_Rules
504                               [NO_ALIGNRP_AFTER_IUP_RULES_SIZE] =
505   {
506     /* Prevent creation of dents in outline */
507     { "-", 0, "", 0 },
508   };
509 
510 
511   /* Don't allow DELTAP after IUP.                                         */
512 #define NO_DELTAP_AFTER_IUP_RULES_SIZE  1
513 
514   static const SPH_TweakRule  NO_DELTAP_AFTER_IUP_Rules
515                               [NO_DELTAP_AFTER_IUP_RULES_SIZE] =
516   {
517     { "-", 0, "", 0 },
518   };
519 
520 
521   /* Don't allow CALL after IUP.                                           */
522 #define NO_CALL_AFTER_IUP_RULES_SIZE  1
523 
524   static const SPH_TweakRule  NO_CALL_AFTER_IUP_Rules
525                               [NO_CALL_AFTER_IUP_RULES_SIZE] =
526   {
527     /* Prevent creation of dents in outline */
528     { "-", 0, "", 0 },
529   };
530 
531 
532   /* De-embolden these glyphs slightly.                                    */
533 #define DEEMBOLDEN_RULES_SIZE  9
534 
535   static const SPH_TweakRule  DEEMBOLDEN_Rules
536                               [DEEMBOLDEN_RULES_SIZE] =
537   {
538     { "Courier New", 0, "Bold", 'A' },
539     { "Courier New", 0, "Bold", 'W' },
540     { "Courier New", 0, "Bold", 'w' },
541     { "Courier New", 0, "Bold", 'M' },
542     { "Courier New", 0, "Bold", 'X' },
543     { "Courier New", 0, "Bold", 'K' },
544     { "Courier New", 0, "Bold", 'x' },
545     { "Courier New", 0, "Bold", 'z' },
546     { "Courier New", 0, "Bold", 'v' },
547   };
548 
549 
550   /* Embolden these glyphs slightly.                                       */
551 #define EMBOLDEN_RULES_SIZE  2
552 
553   static const SPH_TweakRule  EMBOLDEN_Rules
554                               [EMBOLDEN_RULES_SIZE] =
555   {
556     { "Courier New", 0, "Regular", 0 },
557     { "Courier New", 0, "Italic", 0 },
558   };
559 
560 
561   /* This is a CVT hack that makes thick horizontal stems on 2, 5, 7       */
562   /* similar to Windows XP.                                                */
563 #define TIMES_NEW_ROMAN_HACK_RULES_SIZE  12
564 
565   static const SPH_TweakRule  TIMES_NEW_ROMAN_HACK_Rules
566                               [TIMES_NEW_ROMAN_HACK_RULES_SIZE] =
567   {
568     { "Times New Roman", 16, "Italic", '2' },
569     { "Times New Roman", 16, "Italic", '5' },
570     { "Times New Roman", 16, "Italic", '7' },
571     { "Times New Roman", 16, "Regular", '2' },
572     { "Times New Roman", 16, "Regular", '5' },
573     { "Times New Roman", 16, "Regular", '7' },
574     { "Times New Roman", 17, "Italic", '2' },
575     { "Times New Roman", 17, "Italic", '5' },
576     { "Times New Roman", 17, "Italic", '7' },
577     { "Times New Roman", 17, "Regular", '2' },
578     { "Times New Roman", 17, "Regular", '5' },
579     { "Times New Roman", 17, "Regular", '7' },
580   };
581 
582 
583   /* This fudges distance on 2 to get rid of the vanishing stem issue.     */
584   /* A real solution to this is certainly welcome.                         */
585 #define COURIER_NEW_2_HACK_RULES_SIZE  15
586 
587   static const SPH_TweakRule  COURIER_NEW_2_HACK_Rules
588                               [COURIER_NEW_2_HACK_RULES_SIZE] =
589   {
590     { "Courier New", 10, "Regular", '2' },
591     { "Courier New", 11, "Regular", '2' },
592     { "Courier New", 12, "Regular", '2' },
593     { "Courier New", 13, "Regular", '2' },
594     { "Courier New", 14, "Regular", '2' },
595     { "Courier New", 15, "Regular", '2' },
596     { "Courier New", 16, "Regular", '2' },
597     { "Courier New", 17, "Regular", '2' },
598     { "Courier New", 18, "Regular", '2' },
599     { "Courier New", 19, "Regular", '2' },
600     { "Courier New", 20, "Regular", '2' },
601     { "Courier New", 21, "Regular", '2' },
602     { "Courier New", 22, "Regular", '2' },
603     { "Courier New", 23, "Regular", '2' },
604     { "Courier New", 24, "Regular", '2' },
605   };
606 
607 
608 #ifndef FORCE_NATURAL_WIDTHS
609 
610   /* Use compatible widths with these glyphs.  Compatible widths is always */
611   /* on when doing B/W TrueType instructing, but is used selectively here, */
612   /* typically on glyphs with 3 or more vertical stems.                    */
613 #define COMPATIBLE_WIDTHS_RULES_SIZE  38
614 
615   static const SPH_TweakRule  COMPATIBLE_WIDTHS_Rules
616                               [COMPATIBLE_WIDTHS_RULES_SIZE] =
617   {
618     { "Arial Unicode MS", 12, "Regular Class", 'm' },
619     { "Arial Unicode MS", 14, "Regular Class", 'm' },
620     /* Cyrillic small letter sha */
621     { "Arial", 10, "Regular Class", 0x448 },
622     { "Arial", 11, "Regular Class", 'm' },
623     { "Arial", 12, "Regular Class", 'm' },
624     /* Cyrillic small letter sha */
625     { "Arial", 12, "Regular Class", 0x448 },
626     { "Arial", 13, "Regular Class", 0x448 },
627     { "Arial", 14, "Regular Class", 'm' },
628     /* Cyrillic small letter sha */
629     { "Arial", 14, "Regular Class", 0x448 },
630     { "Arial", 15, "Regular Class", 0x448 },
631     { "Arial", 17, "Regular Class", 'm' },
632     { "DejaVu Sans", 15, "Regular Class", 0 },
633     { "Microsoft Sans Serif", 11, "Regular Class", 0 },
634     { "Microsoft Sans Serif", 12, "Regular Class", 0 },
635     { "Segoe UI", 11, "Regular Class", 0 },
636     { "Monaco", 0, "Regular Class", 0 },
637     { "Segoe UI", 12, "Regular Class", 'm' },
638     { "Segoe UI", 14, "Regular Class", 'm' },
639     { "Tahoma", 11, "Regular Class", 0 },
640     { "Times New Roman", 16, "Regular Class", 'c' },
641     { "Times New Roman", 16, "Regular Class", 'm' },
642     { "Times New Roman", 16, "Regular Class", 'o' },
643     { "Times New Roman", 16, "Regular Class", 'w' },
644     { "Trebuchet MS", 11, "Regular Class", 0 },
645     { "Trebuchet MS", 12, "Regular Class", 0 },
646     { "Trebuchet MS", 14, "Regular Class", 0 },
647     { "Trebuchet MS", 15, "Regular Class", 0 },
648     { "Ubuntu", 12, "Regular Class", 'm' },
649     /* Cyrillic small letter sha */
650     { "Verdana", 10, "Regular Class", 0x448 },
651     { "Verdana", 11, "Regular Class", 0x448 },
652     { "Verdana and Clones", 12, "Regular Class", 'i' },
653     { "Verdana and Clones", 12, "Regular Class", 'j' },
654     { "Verdana and Clones", 12, "Regular Class", 'l' },
655     { "Verdana and Clones", 12, "Regular Class", 'm' },
656     { "Verdana and Clones", 13, "Regular Class", 'i' },
657     { "Verdana and Clones", 13, "Regular Class", 'j' },
658     { "Verdana and Clones", 13, "Regular Class", 'l' },
659     { "Verdana and Clones", 14, "Regular Class", 'm' },
660   };
661 
662 
663   /* Scaling slightly in the x-direction prior to hinting results in       */
664   /* more visually pleasing glyphs in certain cases.                       */
665   /* This sometimes needs to be coordinated with compatible width rules.   */
666   /* A value of 1000 corresponds to a scaled value of 1.0.                 */
667 
668 #define X_SCALING_RULES_SIZE  50
669 
670   static const SPH_ScaleRule  X_SCALING_Rules[X_SCALING_RULES_SIZE] =
671   {
672     { "DejaVu Sans", 12, "Regular Class", 'm', 950 },
673     { "Verdana and Clones", 12, "Regular Class", 'a', 1100 },
674     { "Verdana and Clones", 13, "Regular Class", 'a', 1050 },
675     { "Arial", 11, "Regular Class", 'm', 975 },
676     { "Arial", 12, "Regular Class", 'm', 1050 },
677     /* Cyrillic small letter el */
678     { "Arial", 13, "Regular Class", 0x43B, 950 },
679     { "Arial", 13, "Regular Class", 'o', 950 },
680     { "Arial", 13, "Regular Class", 'e', 950 },
681     { "Arial", 14, "Regular Class", 'm', 950 },
682     /* Cyrillic small letter el */
683     { "Arial", 15, "Regular Class", 0x43B, 925 },
684     { "Bitstream Vera Sans", 10, "Regular/Italic Class", 0, 1100 },
685     { "Bitstream Vera Sans", 12, "Regular/Italic Class", 0, 1050 },
686     { "Bitstream Vera Sans", 16, "Regular Class", 0, 1050 },
687     { "Bitstream Vera Sans", 9, "Regular/Italic Class", 0, 1050 },
688     { "DejaVu Sans", 12, "Regular Class", 'l', 975 },
689     { "DejaVu Sans", 12, "Regular Class", 'i', 975 },
690     { "DejaVu Sans", 12, "Regular Class", 'j', 975 },
691     { "DejaVu Sans", 13, "Regular Class", 'l', 950 },
692     { "DejaVu Sans", 13, "Regular Class", 'i', 950 },
693     { "DejaVu Sans", 13, "Regular Class", 'j', 950 },
694     { "DejaVu Sans", 10, "Regular/Italic Class", 0, 1100 },
695     { "DejaVu Sans", 12, "Regular/Italic Class", 0, 1050 },
696     { "Georgia", 10, "", 0, 1050 },
697     { "Georgia", 11, "", 0, 1100 },
698     { "Georgia", 12, "", 0, 1025 },
699     { "Georgia", 13, "", 0, 1050 },
700     { "Georgia", 16, "", 0, 1050 },
701     { "Georgia", 17, "", 0, 1030 },
702     { "Liberation Sans", 12, "Regular Class", 'm', 1100 },
703     { "Lucida Grande", 11, "Regular Class", 'm', 1100 },
704     { "Microsoft Sans Serif", 11, "Regular Class", 'm', 950 },
705     { "Microsoft Sans Serif", 12, "Regular Class", 'm', 1050 },
706     { "Segoe UI", 12, "Regular Class", 'H', 1050 },
707     { "Segoe UI", 12, "Regular Class", 'm', 1050 },
708     { "Segoe UI", 14, "Regular Class", 'm', 1050 },
709     { "Tahoma", 11, "Regular Class", 'i', 975 },
710     { "Tahoma", 11, "Regular Class", 'l', 975 },
711     { "Tahoma", 11, "Regular Class", 'j', 900 },
712     { "Tahoma", 11, "Regular Class", 'm', 918 },
713     { "Verdana", 10, "Regular/Italic Class", 0, 1100 },
714     { "Verdana", 12, "Regular Class", 'm', 975 },
715     { "Verdana", 12, "Regular/Italic Class", 0, 1050 },
716     { "Verdana", 13, "Regular/Italic Class", 'i', 950 },
717     { "Verdana", 13, "Regular/Italic Class", 'j', 950 },
718     { "Verdana", 13, "Regular/Italic Class", 'l', 950 },
719     { "Verdana", 16, "Regular Class", 0, 1050 },
720     { "Verdana", 9, "Regular/Italic Class", 0, 1050 },
721     { "Times New Roman", 16, "Regular Class", 'm', 918 },
722     { "Trebuchet MS", 11, "Regular Class", 'm', 800 },
723     { "Trebuchet MS", 12, "Regular Class", 'm', 800 },
724   };
725 
726 #else
727 
728 #define COMPATIBLE_WIDTHS_RULES_SIZE  1
729 
730   static const SPH_TweakRule  COMPATIBLE_WIDTHS_Rules
731                               [COMPATIBLE_WIDTHS_RULES_SIZE] =
732   {
733     { "-", 0, "", 0 },
734   };
735 
736 
737 #define X_SCALING_RULES_SIZE  1
738 
739   static const SPH_ScaleRule  X_SCALING_Rules
740                               [X_SCALING_RULES_SIZE] =
741   {
742     { "-", 0, "", 0, 1000 },
743   };
744 
745 #endif /* FORCE_NATURAL_WIDTHS */
746 
747 
748   static FT_Bool
is_member_of_family_class(const FT_String * detected_font_name,const FT_String * rule_font_name)749   is_member_of_family_class( const FT_String*  detected_font_name,
750                              const FT_String*  rule_font_name )
751   {
752     FT_UInt  i, j;
753 
754 
755     /* Does font name match rule family? */
756     if ( ft_strcmp( detected_font_name, rule_font_name ) == 0 )
757       return TRUE;
758 
759     /* Is font name a wildcard ""? */
760     if ( ft_strcmp( rule_font_name, "" ) == 0 )
761       return TRUE;
762 
763     /* Is font name contained in a class list? */
764     for ( i = 0; i < FAMILY_CLASS_RULES_SIZE; i++ )
765     {
766       if ( ft_strcmp( FAMILY_CLASS_Rules[i].name, rule_font_name ) == 0 )
767       {
768         for ( j = 0; j < SPH_MAX_CLASS_MEMBERS; j++ )
769         {
770           if ( ft_strcmp( FAMILY_CLASS_Rules[i].member[j], "" ) == 0 )
771             continue;
772           if ( ft_strcmp( FAMILY_CLASS_Rules[i].member[j],
773                           detected_font_name ) == 0 )
774             return TRUE;
775         }
776       }
777     }
778 
779     return FALSE;
780   }
781 
782 
783   static FT_Bool
is_member_of_style_class(const FT_String * detected_font_style,const FT_String * rule_font_style)784   is_member_of_style_class( const FT_String*  detected_font_style,
785                             const FT_String*  rule_font_style )
786   {
787     FT_UInt  i, j;
788 
789 
790     /* Does font style match rule style? */
791     if ( ft_strcmp( detected_font_style, rule_font_style ) == 0 )
792       return TRUE;
793 
794     /* Is font style a wildcard ""? */
795     if ( ft_strcmp( rule_font_style, "" ) == 0 )
796       return TRUE;
797 
798     /* Is font style contained in a class list? */
799     for ( i = 0; i < STYLE_CLASS_RULES_SIZE; i++ )
800     {
801       if ( ft_strcmp( STYLE_CLASS_Rules[i].name, rule_font_style ) == 0 )
802       {
803         for ( j = 0; j < SPH_MAX_CLASS_MEMBERS; j++ )
804         {
805           if ( ft_strcmp( STYLE_CLASS_Rules[i].member[j], "" ) == 0 )
806             continue;
807           if ( ft_strcmp( STYLE_CLASS_Rules[i].member[j],
808                           detected_font_style ) == 0 )
809             return TRUE;
810         }
811       }
812     }
813 
814     return FALSE;
815   }
816 
817 
818   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)819   sph_test_tweak( TT_Face               face,
820                   const FT_String*      family,
821                   FT_UInt               ppem,
822                   const FT_String*      style,
823                   FT_UInt               glyph_index,
824                   const SPH_TweakRule*  rule,
825                   FT_UInt               num_rules )
826   {
827     FT_UInt  i;
828 
829 
830     /* rule checks may be able to be optimized further */
831     for ( i = 0; i < num_rules; i++ )
832     {
833       if ( family                                                   &&
834            ( is_member_of_family_class ( family, rule[i].family ) ) )
835         if ( rule[i].ppem == 0    ||
836              rule[i].ppem == ppem )
837           if ( style                                             &&
838                is_member_of_style_class ( style, rule[i].style ) )
839             if ( rule[i].glyph == 0                                ||
840                  FT_Get_Char_Index( (FT_Face)face,
841                                     rule[i].glyph ) == glyph_index )
842         return TRUE;
843     }
844 
845     return FALSE;
846   }
847 
848 
849   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)850   scale_test_tweak( TT_Face               face,
851                     const FT_String*      family,
852                     FT_UInt               ppem,
853                     const FT_String*      style,
854                     FT_UInt               glyph_index,
855                     const SPH_ScaleRule*  rule,
856                     FT_UInt               num_rules )
857   {
858     FT_UInt  i;
859 
860 
861     /* rule checks may be able to be optimized further */
862     for ( i = 0; i < num_rules; i++ )
863     {
864       if ( family                                                   &&
865            ( is_member_of_family_class ( family, rule[i].family ) ) )
866         if ( rule[i].ppem == 0    ||
867              rule[i].ppem == ppem )
868           if ( style                                            &&
869                is_member_of_style_class( style, rule[i].style ) )
870             if ( rule[i].glyph == 0                                ||
871                  FT_Get_Char_Index( (FT_Face)face,
872                                     rule[i].glyph ) == glyph_index )
873         return rule[i].scale;
874     }
875 
876     return 1000;
877   }
878 
879 
880   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)881   sph_test_tweak_x_scaling( TT_Face           face,
882                             const FT_String*  family,
883                             FT_UInt           ppem,
884                             const FT_String*  style,
885                             FT_UInt           glyph_index )
886   {
887     return scale_test_tweak( face, family, ppem, style, glyph_index,
888                              X_SCALING_Rules, X_SCALING_RULES_SIZE );
889   }
890 
891 
892 #define TWEAK_RULES( x )                                       \
893   if ( sph_test_tweak( face, family, ppem, style, glyph_index, \
894                        x##_Rules, x##_RULES_SIZE ) )           \
895     loader->exec->sph_tweak_flags |= SPH_TWEAK_##x;
896 
897 #define TWEAK_RULES_EXCEPTIONS( x )                                        \
898   if ( sph_test_tweak( face, family, ppem, style, glyph_index,             \
899                        x##_Rules_Exceptions, x##_RULES_EXCEPTIONS_SIZE ) ) \
900     loader->exec->sph_tweak_flags &= ~SPH_TWEAK_##x;
901 
902 
903   FT_LOCAL_DEF( void )
sph_set_tweaks(TT_Loader loader,FT_UInt glyph_index)904   sph_set_tweaks( TT_Loader  loader,
905                   FT_UInt    glyph_index )
906   {
907     TT_Face     face   = loader->face;
908     FT_String*  family = face->root.family_name;
909     FT_UInt     ppem   = loader->size->metrics->x_ppem;
910     FT_String*  style  = face->root.style_name;
911 
912 
913     /* don't apply rules if style isn't set */
914     if ( !face->root.style_name )
915       return;
916 
917 #ifdef SPH_DEBUG_MORE_VERBOSE
918     printf( "%s,%d,%s,%c=%d ",
919             family, ppem, style, glyph_index, glyph_index );
920 #endif
921 
922     TWEAK_RULES( PIXEL_HINTING );
923 
924     if ( loader->exec->sph_tweak_flags & SPH_TWEAK_PIXEL_HINTING )
925     {
926       loader->exec->ignore_x_mode = FALSE;
927       return;
928     }
929 
930     TWEAK_RULES( ALLOW_X_DMOVE );
931     TWEAK_RULES( ALWAYS_DO_DELTAP );
932     TWEAK_RULES( ALWAYS_SKIP_DELTAP );
933     TWEAK_RULES( DEEMBOLDEN );
934     TWEAK_RULES( DO_SHPIX );
935     TWEAK_RULES( EMBOLDEN );
936     TWEAK_RULES( MIAP_HACK );
937     TWEAK_RULES( NORMAL_ROUND );
938     TWEAK_RULES( NO_ALIGNRP_AFTER_IUP );
939     TWEAK_RULES( NO_CALL_AFTER_IUP );
940     TWEAK_RULES( NO_DELTAP_AFTER_IUP );
941     TWEAK_RULES( RASTERIZER_35 );
942     TWEAK_RULES( SKIP_IUP );
943 
944     TWEAK_RULES( SKIP_OFFPIXEL_Y_MOVES );
945     TWEAK_RULES_EXCEPTIONS( SKIP_OFFPIXEL_Y_MOVES );
946 
947     TWEAK_RULES( SKIP_NONPIXEL_Y_MOVES_DELTAP );
948 
949     TWEAK_RULES( SKIP_NONPIXEL_Y_MOVES );
950     TWEAK_RULES_EXCEPTIONS( SKIP_NONPIXEL_Y_MOVES );
951 
952     TWEAK_RULES( ROUND_NONPIXEL_Y_MOVES );
953     TWEAK_RULES_EXCEPTIONS( ROUND_NONPIXEL_Y_MOVES );
954 
955     if ( loader->exec->sph_tweak_flags & SPH_TWEAK_RASTERIZER_35 )
956     {
957       if ( loader->exec->rasterizer_version != TT_INTERPRETER_VERSION_35 )
958       {
959         loader->exec->rasterizer_version = TT_INTERPRETER_VERSION_35;
960         loader->exec->size->cvt_ready    = -1;
961 
962         tt_size_ready_bytecode(
963           loader->exec->size,
964           FT_BOOL( loader->load_flags & FT_LOAD_PEDANTIC ) );
965       }
966       else
967         loader->exec->rasterizer_version = TT_INTERPRETER_VERSION_35;
968     }
969     else
970     {
971       if ( loader->exec->rasterizer_version  !=
972            SPH_OPTION_SET_RASTERIZER_VERSION )
973       {
974         loader->exec->rasterizer_version = SPH_OPTION_SET_RASTERIZER_VERSION;
975         loader->exec->size->cvt_ready    = -1;
976 
977         tt_size_ready_bytecode(
978           loader->exec->size,
979           FT_BOOL( loader->load_flags & FT_LOAD_PEDANTIC ) );
980       }
981       else
982         loader->exec->rasterizer_version = SPH_OPTION_SET_RASTERIZER_VERSION;
983     }
984 
985     if ( IS_HINTED( loader->load_flags ) )
986     {
987       TWEAK_RULES( TIMES_NEW_ROMAN_HACK );
988       TWEAK_RULES( COURIER_NEW_2_HACK );
989     }
990 
991     if ( sph_test_tweak( face, family, ppem, style, glyph_index,
992            COMPATIBILITY_MODE_Rules, COMPATIBILITY_MODE_RULES_SIZE ) )
993       loader->exec->face->sph_compatibility_mode = TRUE;
994 
995 
996     if ( IS_HINTED( loader->load_flags ) )
997     {
998       if ( sph_test_tweak( face, family, ppem, style, glyph_index,
999              COMPATIBLE_WIDTHS_Rules, COMPATIBLE_WIDTHS_RULES_SIZE ) )
1000         loader->exec->compatible_widths |= TRUE;
1001     }
1002   }
1003 
1004 #else /* !(TT_USE_BYTECODE_INTERPRETER &&          */
1005       /*   TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY) */
1006 
1007   /* ANSI C doesn't like empty source files */
1008   typedef int  _tt_subpix_dummy;
1009 
1010 #endif /* !(TT_USE_BYTECODE_INTERPRETER &&          */
1011        /*   TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY) */
1012 
1013 
1014 /* END */
1015