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1 /***************************************************************************/ | |
2 /* */ | |
3 /* cf2blues.c */ | |
4 /* */ | |
5 /* Adobe's code for handling Blue Zones (body). */ | |
6 /* */ | |
7 /* Copyright 2009-2013 Adobe Systems Incorporated. */ | |
8 /* */ | |
9 /* This software, and all works of authorship, whether in source or */ | |
10 /* object code form as indicated by the copyright notice(s) included */ | |
11 /* herein (collectively, the "Work") is made available, and may only be */ | |
12 /* used, modified, and distributed under the FreeType Project License, */ | |
13 /* LICENSE.TXT. Additionally, subject to the terms and conditions of the */ | |
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15 /* to any individual or legal entity exercising permissions granted by */ | |
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17 /* "Your") a perpetual, worldwide, non-exclusive, no-charge, */ | |
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29 /* the date such litigation is filed. */ | |
30 /* */ | |
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32 /* have read and understood the terms and conditions of the */ | |
33 /* FreeType Project License as well as those provided in this section, */ | |
34 /* and you accept them fully. */ | |
35 /* */ | |
36 /***************************************************************************/ | |
37 | |
38 | |
39 #include "cf2ft.h" | |
40 #include "../../include/freetype/internal/ftdebug.h" | |
41 | |
42 #include "cf2blues.h" | |
43 #include "cf2hints.h" | |
44 #include "cf2font.h" | |
45 | |
46 | |
47 /*************************************************************************/ | |
48 /* */ | |
49 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ | |
50 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ | |
51 /* messages during execution. */ | |
52 /* */ | |
53 #undef FT_COMPONENT | |
54 #define FT_COMPONENT trace_cf2blues | |
55 | |
56 | |
57 /* | |
58 * For blue values, the FreeType parser produces an array of integers, | |
59 * while the Adobe CFF engine produces an array of fixed. | |
60 * Define a macro to convert FreeType to fixed. | |
61 */ | |
62 #define cf2_blueToFixed( x ) cf2_intToFixed( x ) | |
63 | |
64 | |
65 FT_LOCAL_DEF( void ) | |
66 cf2_blues_init( CF2_Blues blues, | |
67 CF2_Font font ) | |
68 { | |
69 /* pointer to parsed font object */ | |
70 CFF_Decoder* decoder = font->decoder; | |
71 | |
72 CF2_Fixed zoneHeight; | |
73 CF2_Fixed maxZoneHeight = 0; | |
74 CF2_Fixed csUnitsPerPixel; | |
75 | |
76 size_t numBlueValues; | |
77 size_t numOtherBlues; | |
78 size_t numFamilyBlues; | |
79 size_t numFamilyOtherBlues; | |
80 | |
81 FT_Pos* blueValues; | |
82 FT_Pos* otherBlues; | |
83 FT_Pos* familyBlues; | |
84 FT_Pos* familyOtherBlues; | |
85 | |
86 size_t i; | |
87 CF2_Fixed emBoxBottom, emBoxTop; | |
88 | |
89 CF2_Int unitsPerEm = font->unitsPerEm; | |
90 | |
91 | |
92 if ( unitsPerEm == 0 ) | |
93 unitsPerEm = 1000; | |
94 | |
95 FT_ZERO( blues ); | |
96 blues->scale = font->innerTransform.d; | |
97 | |
98 cf2_getBlueMetrics( decoder, | |
99 &blues->blueScale, | |
100 &blues->blueShift, | |
101 &blues->blueFuzz ); | |
102 | |
103 cf2_getBlueValues( decoder, &numBlueValues, &blueValues ); | |
104 cf2_getOtherBlues( decoder, &numOtherBlues, &otherBlues ); | |
105 cf2_getFamilyBlues( decoder, &numFamilyBlues, &familyBlues ); | |
106 cf2_getFamilyOtherBlues( decoder, &numFamilyOtherBlues, &familyOtherBlues ); | |
107 | |
108 /* | |
109 * synthetic em box hint heuristic | |
110 * | |
111 * Apply this when ideographic dictionary (LanguageGroup 1) has no | |
112 * real alignment zones. Adobe tools generate dummy zones at -250 and | |
113 * 1100 for a 1000 unit em. Fonts with ICF-based alignment zones | |
114 * should not enable the heuristic. When the heuristic is enabled, | |
115 * the font's blue zones are ignored. | |
116 * | |
117 */ | |
118 | |
119 /* get em box from OS/2 typoAscender/Descender */ | |
120 /* TODO: FreeType does not parse these metrics. Skip them for now. */ | |
121 #if 0 | |
122 FCM_getHorizontalLineMetrics( &e, | |
123 font->font, | |
124 &ascender, | |
125 &descender, | |
126 &linegap ); | |
127 if ( ascender - descender == unitsPerEm ) | |
128 { | |
129 emBoxBottom = cf2_intToFixed( descender ); | |
130 emBoxTop = cf2_intToFixed( ascender ); | |
131 } | |
132 else | |
133 #endif | |
134 { | |
135 emBoxBottom = CF2_ICF_Bottom; | |
136 emBoxTop = CF2_ICF_Top; | |
137 } | |
138 | |
139 if ( cf2_getLanguageGroup( decoder ) == 1 && | |
140 ( numBlueValues == 0 || | |
141 ( numBlueValues == 4 && | |
142 cf2_blueToFixed( blueValues[0] ) < emBoxBottom && | |
143 cf2_blueToFixed( blueValues[1] ) < emBoxBottom && | |
144 cf2_blueToFixed( blueValues[2] ) > emBoxTop && | |
145 cf2_blueToFixed( blueValues[3] ) > emBoxTop ) ) ) | |
146 { | |
147 /* | |
148 * Construct hint edges suitable for synthetic ghost hints at top | |
149 * and bottom of em box. +-CF2_MIN_COUNTER allows for unhinted | |
150 * features above or below the last hinted edge. This also gives a | |
151 * net 1 pixel boost to the height of ideographic glyphs. | |
152 * | |
153 * Note: Adjust synthetic hints outward by epsilon (0x.0001) to | |
154 * avoid interference. E.g., some fonts have real hints at | |
155 * 880 and -120. | |
156 */ | |
157 | |
158 blues->emBoxBottomEdge.csCoord = emBoxBottom - CF2_FIXED_EPSILON; | |
159 blues->emBoxBottomEdge.dsCoord = cf2_fixedRound( | |
160 FT_MulFix( | |
161 blues->emBoxBottomEdge.csCoord, | |
162 blues->scale ) ) - | |
163 CF2_MIN_COUNTER; | |
164 blues->emBoxBottomEdge.scale = blues->scale; | |
165 blues->emBoxBottomEdge.flags = CF2_GhostBottom | | |
166 CF2_Locked | | |
167 CF2_Synthetic; | |
168 | |
169 blues->emBoxTopEdge.csCoord = emBoxTop + CF2_FIXED_EPSILON + | |
170 2 * font->darkenY; | |
171 blues->emBoxTopEdge.dsCoord = cf2_fixedRound( | |
172 FT_MulFix( | |
173 blues->emBoxTopEdge.csCoord, | |
174 blues->scale ) ) + | |
175 CF2_MIN_COUNTER; | |
176 blues->emBoxTopEdge.scale = blues->scale; | |
177 blues->emBoxTopEdge.flags = CF2_GhostTop | | |
178 CF2_Locked | | |
179 CF2_Synthetic; | |
180 | |
181 blues->doEmBoxHints = TRUE; /* enable the heuristic */ | |
182 | |
183 return; | |
184 } | |
185 | |
186 /* copy `BlueValues' and `OtherBlues' to a combined array of top and */ | |
187 /* bottom zones */ | |
188 for ( i = 0; i < numBlueValues; i += 2 ) | |
189 { | |
190 blues->zone[blues->count].csBottomEdge = | |
191 cf2_blueToFixed( blueValues[i] ); | |
192 blues->zone[blues->count].csTopEdge = | |
193 cf2_blueToFixed( blueValues[i + 1] ); | |
194 | |
195 zoneHeight = blues->zone[blues->count].csTopEdge - | |
196 blues->zone[blues->count].csBottomEdge; | |
197 | |
198 if ( zoneHeight < 0 ) | |
199 { | |
200 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); | |
201 continue; /* reject this zone */ | |
202 } | |
203 | |
204 if ( zoneHeight > maxZoneHeight ) | |
205 { | |
206 /* take maximum before darkening adjustment */ | |
207 /* so overshoot suppression point doesn't change */ | |
208 maxZoneHeight = zoneHeight; | |
209 } | |
210 | |
211 /* adjust both edges of top zone upward by twice darkening amount */ | |
212 if ( i != 0 ) | |
213 { | |
214 blues->zone[blues->count].csTopEdge += 2 * font->darkenY; | |
215 blues->zone[blues->count].csBottomEdge += 2 * font->darkenY; | |
216 } | |
217 | |
218 /* first `BlueValue' is bottom zone; others are top */ | |
219 if ( i == 0 ) | |
220 { | |
221 blues->zone[blues->count].bottomZone = | |
222 TRUE; | |
223 blues->zone[blues->count].csFlatEdge = | |
224 blues->zone[blues->count].csTopEdge; | |
225 } | |
226 else | |
227 { | |
228 blues->zone[blues->count].bottomZone = | |
229 FALSE; | |
230 blues->zone[blues->count].csFlatEdge = | |
231 blues->zone[blues->count].csBottomEdge; | |
232 } | |
233 | |
234 blues->count += 1; | |
235 } | |
236 | |
237 for ( i = 0; i < numOtherBlues; i += 2 ) | |
238 { | |
239 blues->zone[blues->count].csBottomEdge = | |
240 cf2_blueToFixed( otherBlues[i] ); | |
241 blues->zone[blues->count].csTopEdge = | |
242 cf2_blueToFixed( otherBlues[i + 1] ); | |
243 | |
244 zoneHeight = blues->zone[blues->count].csTopEdge - | |
245 blues->zone[blues->count].csBottomEdge; | |
246 | |
247 if ( zoneHeight < 0 ) | |
248 { | |
249 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); | |
250 continue; /* reject this zone */ | |
251 } | |
252 | |
253 if ( zoneHeight > maxZoneHeight ) | |
254 { | |
255 /* take maximum before darkening adjustment */ | |
256 /* so overshoot suppression point doesn't change */ | |
257 maxZoneHeight = zoneHeight; | |
258 } | |
259 | |
260 /* Note: bottom zones are not adjusted for darkening amount */ | |
261 | |
262 /* all OtherBlues are bottom zone */ | |
263 blues->zone[blues->count].bottomZone = | |
264 TRUE; | |
265 blues->zone[blues->count].csFlatEdge = | |
266 blues->zone[blues->count].csTopEdge; | |
267 | |
268 blues->count += 1; | |
269 } | |
270 | |
271 /* Adjust for FamilyBlues */ | |
272 | |
273 /* Search for the nearest flat edge in `FamilyBlues' or */ | |
274 /* `FamilyOtherBlues'. According to the Black Book, any matching edge */ | |
275 /* must be within one device pixel */ | |
276 | |
277 csUnitsPerPixel = FT_DivFix( cf2_intToFixed( 1 ), blues->scale ); | |
278 | |
279 /* loop on all zones in this font */ | |
280 for ( i = 0; i < blues->count; i++ ) | |
281 { | |
282 size_t j; | |
283 CF2_Fixed minDiff; | |
284 CF2_Fixed flatFamilyEdge, diff; | |
285 /* value for this font */ | |
286 CF2_Fixed flatEdge = blues->zone[i].csFlatEdge; | |
287 | |
288 | |
289 if ( blues->zone[i].bottomZone ) | |
290 { | |
291 /* In a bottom zone, the top edge is the flat edge. */ | |
292 /* Search `FamilyOtherBlues' for bottom zones; look for closest */ | |
293 /* Family edge that is within the one pixel threshold. */ | |
294 | |
295 minDiff = CF2_FIXED_MAX; | |
296 | |
297 for ( j = 0; j < numFamilyOtherBlues; j += 2 ) | |
298 { | |
299 /* top edge */ | |
300 flatFamilyEdge = cf2_blueToFixed( familyOtherBlues[j + 1] ); | |
301 | |
302 diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); | |
303 | |
304 if ( diff < minDiff && diff < csUnitsPerPixel ) | |
305 { | |
306 blues->zone[i].csFlatEdge = flatFamilyEdge; | |
307 minDiff = diff; | |
308 | |
309 if ( diff == 0 ) | |
310 break; | |
311 } | |
312 } | |
313 | |
314 /* check the first member of FamilyBlues, which is a bottom zone */ | |
315 if ( numFamilyBlues >= 2 ) | |
316 { | |
317 /* top edge */ | |
318 flatFamilyEdge = cf2_blueToFixed( familyBlues[1] ); | |
319 | |
320 diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); | |
321 | |
322 if ( diff < minDiff && diff < csUnitsPerPixel ) | |
323 blues->zone[i].csFlatEdge = flatFamilyEdge; | |
324 } | |
325 } | |
326 else | |
327 { | |
328 /* In a top zone, the bottom edge is the flat edge. */ | |
329 /* Search `FamilyBlues' for top zones; skip first zone, which is a */ | |
330 /* bottom zone; look for closest Family edge that is within the */ | |
331 /* one pixel threshold */ | |
332 | |
333 minDiff = CF2_FIXED_MAX; | |
334 | |
335 for ( j = 2; j < numFamilyBlues; j += 2 ) | |
336 { | |
337 /* bottom edge */ | |
338 flatFamilyEdge = cf2_blueToFixed( familyBlues[j] ); | |
339 | |
340 /* adjust edges of top zone upward by twice darkening amount */ | |
341 flatFamilyEdge += 2 * font->darkenY; /* bottom edge */ | |
342 | |
343 diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); | |
344 | |
345 if ( diff < minDiff && diff < csUnitsPerPixel ) | |
346 { | |
347 blues->zone[i].csFlatEdge = flatFamilyEdge; | |
348 minDiff = diff; | |
349 | |
350 if ( diff == 0 ) | |
351 break; | |
352 } | |
353 } | |
354 } | |
355 } | |
356 | |
357 /* TODO: enforce separation of zones, including BlueFuzz */ | |
358 | |
359 /* Adjust BlueScale; similar to AdjustBlueScale() in coretype */ | |
360 /* `bcsetup.c'. */ | |
361 | |
362 if ( maxZoneHeight > 0 ) | |
363 { | |
364 if ( blues->blueScale > FT_DivFix( cf2_intToFixed( 1 ), | |
365 maxZoneHeight ) ) | |
366 { | |
367 /* clamp at maximum scale */ | |
368 blues->blueScale = FT_DivFix( cf2_intToFixed( 1 ), | |
369 maxZoneHeight ); | |
370 } | |
371 | |
372 /* | |
373 * TODO: Revisit the bug fix for 613448. The minimum scale | |
374 * requirement catches a number of library fonts. For | |
375 * example, with default BlueScale (.039625) and 0.4 minimum, | |
376 * the test below catches any font with maxZoneHeight < 10.1. | |
377 * There are library fonts ranging from 2 to 10 that get | |
378 * caught, including e.g., Eurostile LT Std Medium with | |
379 * maxZoneHeight of 6. | |
380 * | |
381 */ | |
382 #if 0 | |
383 if ( blueScale < .4 / maxZoneHeight ) | |
384 { | |
385 tetraphilia_assert( 0 ); | |
386 /* clamp at minimum scale, per bug 0613448 fix */ | |
387 blueScale = .4 / maxZoneHeight; | |
388 } | |
389 #endif | |
390 | |
391 } | |
392 | |
393 /* | |
394 * Suppress overshoot and boost blue zones at small sizes. Boost | |
395 * amount varies linearly from 0.5 pixel near 0 to 0 pixel at | |
396 * blueScale cutoff. | |
397 * Note: This boost amount is different from the coretype heuristic. | |
398 * | |
399 */ | |
400 | |
401 if ( blues->scale < blues->blueScale ) | |
402 { | |
403 blues->suppressOvershoot = TRUE; | |
404 | |
405 /* Change rounding threshold for `dsFlatEdge'. */ | |
406 /* Note: constant changed from 0.5 to 0.6 to avoid a problem with */ | |
407 /* 10ppem Arial */ | |
408 | |
409 blues->boost = FT_MulFix( | |
410 cf2_floatToFixed( .6 ), | |
411 ( cf2_intToFixed( 1 ) - | |
412 FT_DivFix( blues->scale, | |
413 blues->blueScale ) ) ); | |
414 if ( blues->boost > 0x7FFF ) | |
415 { | |
416 /* boost must remain less than 0.5, or baseline could go negative */ | |
417 blues->boost = 0x7FFF; | |
418 } | |
419 } | |
420 | |
421 /* boost and darkening have similar effects; don't do both */ | |
422 if ( font->stemDarkened ) | |
423 blues->boost = 0; | |
424 | |
425 /* set device space alignment for each zone; */ | |
426 /* apply boost amount before rounding flat edge */ | |
427 | |
428 for ( i = 0; i < blues->count; i++ ) | |
429 { | |
430 if ( blues->zone[i].bottomZone ) | |
431 blues->zone[i].dsFlatEdge = cf2_fixedRound( | |
432 FT_MulFix( | |
433 blues->zone[i].csFlatEdge, | |
434 blues->scale ) - | |
435 blues->boost ); | |
436 else | |
437 blues->zone[i].dsFlatEdge = cf2_fixedRound( | |
438 FT_MulFix( | |
439 blues->zone[i].csFlatEdge, | |
440 blues->scale ) + | |
441 blues->boost ); | |
442 } | |
443 } | |
444 | |
445 | |
446 /* | |
447 * Check whether `stemHint' is captured by one of the blue zones. | |
448 * | |
449 * Zero, one or both edges may be valid; only valid edges can be | |
450 * captured. For compatibility with CoolType, search top and bottom | |
451 * zones in the same pass (see `BlueLock'). If a hint is captured, | |
452 * return true and position the edge(s) in one of 3 ways: | |
453 * | |
454 * 1) If `BlueScale' suppresses overshoot, position the captured edge | |
455 * at the flat edge of the zone. | |
456 * 2) If overshoot is not suppressed and `BlueShift' requires | |
457 * overshoot, position the captured edge a minimum of 1 device pixel | |
458 * from the flat edge. | |
459 * 3) If overshoot is not suppressed or required, position the captured | |
460 * edge at the nearest device pixel. | |
461 * | |
462 */ | |
463 FT_LOCAL_DEF( FT_Bool ) | |
464 cf2_blues_capture( const CF2_Blues blues, | |
465 CF2_Hint bottomHintEdge, | |
466 CF2_Hint topHintEdge ) | |
467 { | |
468 /* TODO: validate? */ | |
469 CF2_Fixed csFuzz = blues->blueFuzz; | |
470 | |
471 /* new position of captured edge */ | |
472 CF2_Fixed dsNew; | |
473 | |
474 /* amount that hint is moved when positioned */ | |
475 CF2_Fixed dsMove = 0; | |
476 | |
477 FT_Bool captured = FALSE; | |
478 CF2_UInt i; | |
479 | |
480 | |
481 /* assert edge flags are consistent */ | |
482 FT_ASSERT( !cf2_hint_isTop( bottomHintEdge ) && | |
483 !cf2_hint_isBottom( topHintEdge ) ); | |
484 | |
485 /* TODO: search once without blue fuzz for compatibility with coretype? */ | |
486 for ( i = 0; i < blues->count; i++ ) | |
487 { | |
488 if ( blues->zone[i].bottomZone && | |
489 cf2_hint_isBottom( bottomHintEdge ) ) | |
490 { | |
491 if ( ( blues->zone[i].csBottomEdge - csFuzz ) <= | |
492 bottomHintEdge->csCoord && | |
493 bottomHintEdge->csCoord <= | |
494 ( blues->zone[i].csTopEdge + csFuzz ) ) | |
495 { | |
496 /* bottom edge captured by bottom zone */ | |
497 | |
498 if ( blues->suppressOvershoot ) | |
499 dsNew = blues->zone[i].dsFlatEdge; | |
500 | |
501 else if ( ( blues->zone[i].csTopEdge - bottomHintEdge->csCoord ) >= | |
502 blues->blueShift ) | |
503 { | |
504 /* guarantee minimum of 1 pixel overshoot */ | |
505 dsNew = FT_MIN( | |
506 cf2_fixedRound( bottomHintEdge->dsCoord ), | |
507 blues->zone[i].dsFlatEdge - cf2_intToFixed( 1 ) ); | |
508 } | |
509 | |
510 else | |
511 { | |
512 /* simply round captured edge */ | |
513 dsNew = cf2_fixedRound( bottomHintEdge->dsCoord ); | |
514 } | |
515 | |
516 dsMove = dsNew - bottomHintEdge->dsCoord; | |
517 captured = TRUE; | |
518 | |
519 break; | |
520 } | |
521 } | |
522 | |
523 if ( !blues->zone[i].bottomZone && cf2_hint_isTop( topHintEdge ) ) | |
524 { | |
525 if ( ( blues->zone[i].csBottomEdge - csFuzz ) <= | |
526 topHintEdge->csCoord && | |
527 topHintEdge->csCoord <= | |
528 ( blues->zone[i].csTopEdge + csFuzz ) ) | |
529 { | |
530 /* top edge captured by top zone */ | |
531 | |
532 if ( blues->suppressOvershoot ) | |
533 dsNew = blues->zone[i].dsFlatEdge; | |
534 | |
535 else if ( ( topHintEdge->csCoord - blues->zone[i].csBottomEdge ) >= | |
536 blues->blueShift ) | |
537 { | |
538 /* guarantee minimum of 1 pixel overshoot */ | |
539 dsNew = FT_MAX( | |
540 cf2_fixedRound( topHintEdge->dsCoord ), | |
541 blues->zone[i].dsFlatEdge + cf2_intToFixed( 1 ) ); | |
542 } | |
543 | |
544 else | |
545 { | |
546 /* simply round captured edge */ | |
547 dsNew = cf2_fixedRound( topHintEdge->dsCoord ); | |
548 } | |
549 | |
550 dsMove = dsNew - topHintEdge->dsCoord; | |
551 captured = TRUE; | |
552 | |
553 break; | |
554 } | |
555 } | |
556 } | |
557 | |
558 if ( captured ) | |
559 { | |
560 /* move both edges and flag them `locked' */ | |
561 if ( cf2_hint_isValid( bottomHintEdge ) ) | |
562 { | |
563 bottomHintEdge->dsCoord += dsMove; | |
564 cf2_hint_lock( bottomHintEdge ); | |
565 } | |
566 | |
567 if ( cf2_hint_isValid( topHintEdge ) ) | |
568 { | |
569 topHintEdge->dsCoord += dsMove; | |
570 cf2_hint_lock( topHintEdge ); | |
571 } | |
572 } | |
573 | |
574 return captured; | |
575 } | |
576 | |
577 | |
578 /* END */ | |
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