1 | /**************************************************************************** |
2 | * |
3 | * psblues.c |
4 | * |
5 | * Adobe's code for handling Blue Zones (body). |
6 | * |
7 | * Copyright 2009-2014 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 |
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36 | */ |
37 | |
38 | |
39 | #include "psft.h" |
40 | #include <freetype/internal/ftdebug.h> |
41 | |
42 | #include "psblues.h" |
43 | #include "pshints.h" |
44 | #include "psfont.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 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 | PS_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 | #if 0 |
90 | CF2_Int unitsPerEm = font->unitsPerEm; |
91 | |
92 | |
93 | if ( unitsPerEm == 0 ) |
94 | unitsPerEm = 1000; |
95 | #endif |
96 | |
97 | FT_ZERO( blues ); |
98 | blues->scale = font->innerTransform.d; |
99 | |
100 | cf2_getBlueMetrics( decoder, |
101 | &blues->blueScale, |
102 | &blues->blueShift, |
103 | &blues->blueFuzz ); |
104 | |
105 | cf2_getBlueValues( decoder, &numBlueValues, &blueValues ); |
106 | cf2_getOtherBlues( decoder, &numOtherBlues, &otherBlues ); |
107 | cf2_getFamilyBlues( decoder, &numFamilyBlues, &familyBlues ); |
108 | cf2_getFamilyOtherBlues( decoder, &numFamilyOtherBlues, &familyOtherBlues ); |
109 | |
110 | /* |
111 | * synthetic em box hint heuristic |
112 | * |
113 | * Apply this when ideographic dictionary (LanguageGroup 1) has no |
114 | * real alignment zones. Adobe tools generate dummy zones at -250 and |
115 | * 1100 for a 1000 unit em. Fonts with ICF-based alignment zones |
116 | * should not enable the heuristic. When the heuristic is enabled, |
117 | * the font's blue zones are ignored. |
118 | * |
119 | */ |
120 | |
121 | /* get em box from OS/2 typoAscender/Descender */ |
122 | /* TODO: FreeType does not parse these metrics. Skip them for now. */ |
123 | #if 0 |
124 | FCM_getHorizontalLineMetrics( &e, |
125 | font->font, |
126 | &ascender, |
127 | &descender, |
128 | &linegap ); |
129 | if ( ascender - descender == unitsPerEm ) |
130 | { |
131 | emBoxBottom = cf2_intToFixed( descender ); |
132 | emBoxTop = cf2_intToFixed( ascender ); |
133 | } |
134 | else |
135 | #endif |
136 | { |
137 | emBoxBottom = CF2_ICF_Bottom; |
138 | emBoxTop = CF2_ICF_Top; |
139 | } |
140 | |
141 | if ( cf2_getLanguageGroup( decoder ) == 1 && |
142 | ( numBlueValues == 0 || |
143 | ( numBlueValues == 4 && |
144 | cf2_blueToFixed( blueValues[0] ) < emBoxBottom && |
145 | cf2_blueToFixed( blueValues[1] ) < emBoxBottom && |
146 | cf2_blueToFixed( blueValues[2] ) > emBoxTop && |
147 | cf2_blueToFixed( blueValues[3] ) > emBoxTop ) ) ) |
148 | { |
149 | /* |
150 | * Construct hint edges suitable for synthetic ghost hints at top |
151 | * and bottom of em box. +-CF2_MIN_COUNTER allows for unhinted |
152 | * features above or below the last hinted edge. This also gives a |
153 | * net 1 pixel boost to the height of ideographic glyphs. |
154 | * |
155 | * Note: Adjust synthetic hints outward by epsilon (0x.0001) to |
156 | * avoid interference. E.g., some fonts have real hints at |
157 | * 880 and -120. |
158 | */ |
159 | |
160 | blues->emBoxBottomEdge.csCoord = emBoxBottom - CF2_FIXED_EPSILON; |
161 | blues->emBoxBottomEdge.dsCoord = cf2_fixedRound( |
162 | FT_MulFix( |
163 | blues->emBoxBottomEdge.csCoord, |
164 | blues->scale ) ) - |
165 | CF2_MIN_COUNTER; |
166 | blues->emBoxBottomEdge.scale = blues->scale; |
167 | blues->emBoxBottomEdge.flags = CF2_GhostBottom | |
168 | CF2_Locked | |
169 | CF2_Synthetic; |
170 | |
171 | blues->emBoxTopEdge.csCoord = emBoxTop + CF2_FIXED_EPSILON + |
172 | 2 * font->darkenY; |
173 | blues->emBoxTopEdge.dsCoord = cf2_fixedRound( |
174 | FT_MulFix( |
175 | blues->emBoxTopEdge.csCoord, |
176 | blues->scale ) ) + |
177 | CF2_MIN_COUNTER; |
178 | blues->emBoxTopEdge.scale = blues->scale; |
179 | blues->emBoxTopEdge.flags = CF2_GhostTop | |
180 | CF2_Locked | |
181 | CF2_Synthetic; |
182 | |
183 | blues->doEmBoxHints = TRUE; /* enable the heuristic */ |
184 | |
185 | return; |
186 | } |
187 | |
188 | /* copy `BlueValues' and `OtherBlues' to a combined array of top and */ |
189 | /* bottom zones */ |
190 | for ( i = 0; i < numBlueValues; i += 2 ) |
191 | { |
192 | blues->zone[blues->count].csBottomEdge = |
193 | cf2_blueToFixed( blueValues[i] ); |
194 | blues->zone[blues->count].csTopEdge = |
195 | cf2_blueToFixed( blueValues[i + 1] ); |
196 | |
197 | zoneHeight = SUB_INT32( blues->zone[blues->count].csTopEdge, |
198 | blues->zone[blues->count].csBottomEdge ); |
199 | |
200 | if ( zoneHeight < 0 ) |
201 | { |
202 | FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); |
203 | continue; /* reject this zone */ |
204 | } |
205 | |
206 | if ( zoneHeight > maxZoneHeight ) |
207 | { |
208 | /* take maximum before darkening adjustment */ |
209 | /* so overshoot suppression point doesn't change */ |
210 | maxZoneHeight = zoneHeight; |
211 | } |
212 | |
213 | /* adjust both edges of top zone upward by twice darkening amount */ |
214 | if ( i != 0 ) |
215 | { |
216 | blues->zone[blues->count].csTopEdge += 2 * font->darkenY; |
217 | blues->zone[blues->count].csBottomEdge += 2 * font->darkenY; |
218 | } |
219 | |
220 | /* first `BlueValue' is bottom zone; others are top */ |
221 | if ( i == 0 ) |
222 | { |
223 | blues->zone[blues->count].bottomZone = |
224 | TRUE; |
225 | blues->zone[blues->count].csFlatEdge = |
226 | blues->zone[blues->count].csTopEdge; |
227 | } |
228 | else |
229 | { |
230 | blues->zone[blues->count].bottomZone = |
231 | FALSE; |
232 | blues->zone[blues->count].csFlatEdge = |
233 | blues->zone[blues->count].csBottomEdge; |
234 | } |
235 | |
236 | blues->count += 1; |
237 | } |
238 | |
239 | for ( i = 0; i < numOtherBlues; i += 2 ) |
240 | { |
241 | blues->zone[blues->count].csBottomEdge = |
242 | cf2_blueToFixed( otherBlues[i] ); |
243 | blues->zone[blues->count].csTopEdge = |
244 | cf2_blueToFixed( otherBlues[i + 1] ); |
245 | |
246 | zoneHeight = SUB_INT32( blues->zone[blues->count].csTopEdge, |
247 | blues->zone[blues->count].csBottomEdge ); |
248 | |
249 | if ( zoneHeight < 0 ) |
250 | { |
251 | FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); |
252 | continue; /* reject this zone */ |
253 | } |
254 | |
255 | if ( zoneHeight > maxZoneHeight ) |
256 | { |
257 | /* take maximum before darkening adjustment */ |
258 | /* so overshoot suppression point doesn't change */ |
259 | maxZoneHeight = zoneHeight; |
260 | } |
261 | |
262 | /* Note: bottom zones are not adjusted for darkening amount */ |
263 | |
264 | /* all OtherBlues are bottom zone */ |
265 | blues->zone[blues->count].bottomZone = |
266 | TRUE; |
267 | blues->zone[blues->count].csFlatEdge = |
268 | blues->zone[blues->count].csTopEdge; |
269 | |
270 | blues->count += 1; |
271 | } |
272 | |
273 | /* Adjust for FamilyBlues */ |
274 | |
275 | /* Search for the nearest flat edge in `FamilyBlues' or */ |
276 | /* `FamilyOtherBlues'. According to the Black Book, any matching edge */ |
277 | /* must be within one device pixel */ |
278 | |
279 | csUnitsPerPixel = FT_DivFix( cf2_intToFixed( 1 ), blues->scale ); |
280 | |
281 | /* loop on all zones in this font */ |
282 | for ( i = 0; i < blues->count; i++ ) |
283 | { |
284 | size_t j; |
285 | CF2_Fixed minDiff; |
286 | CF2_Fixed flatFamilyEdge, diff; |
287 | /* value for this font */ |
288 | CF2_Fixed flatEdge = blues->zone[i].csFlatEdge; |
289 | |
290 | |
291 | if ( blues->zone[i].bottomZone ) |
292 | { |
293 | /* In a bottom zone, the top edge is the flat edge. */ |
294 | /* Search `FamilyOtherBlues' for bottom zones; look for closest */ |
295 | /* Family edge that is within the one pixel threshold. */ |
296 | |
297 | minDiff = CF2_FIXED_MAX; |
298 | |
299 | for ( j = 0; j < numFamilyOtherBlues; j += 2 ) |
300 | { |
301 | /* top edge */ |
302 | flatFamilyEdge = cf2_blueToFixed( familyOtherBlues[j + 1] ); |
303 | |
304 | diff = cf2_fixedAbs( SUB_INT32( flatEdge, flatFamilyEdge ) ); |
305 | |
306 | if ( diff < minDiff && diff < csUnitsPerPixel ) |
307 | { |
308 | blues->zone[i].csFlatEdge = flatFamilyEdge; |
309 | minDiff = diff; |
310 | |
311 | if ( diff == 0 ) |
312 | break; |
313 | } |
314 | } |
315 | |
316 | /* check the first member of FamilyBlues, which is a bottom zone */ |
317 | if ( numFamilyBlues >= 2 ) |
318 | { |
319 | /* top edge */ |
320 | flatFamilyEdge = cf2_blueToFixed( familyBlues[1] ); |
321 | |
322 | diff = cf2_fixedAbs( SUB_INT32( flatEdge, flatFamilyEdge ) ); |
323 | |
324 | if ( diff < minDiff && diff < csUnitsPerPixel ) |
325 | blues->zone[i].csFlatEdge = flatFamilyEdge; |
326 | } |
327 | } |
328 | else |
329 | { |
330 | /* In a top zone, the bottom edge is the flat edge. */ |
331 | /* Search `FamilyBlues' for top zones; skip first zone, which is a */ |
332 | /* bottom zone; look for closest Family edge that is within the */ |
333 | /* one pixel threshold */ |
334 | |
335 | minDiff = CF2_FIXED_MAX; |
336 | |
337 | for ( j = 2; j < numFamilyBlues; j += 2 ) |
338 | { |
339 | /* bottom edge */ |
340 | flatFamilyEdge = cf2_blueToFixed( familyBlues[j] ); |
341 | |
342 | /* adjust edges of top zone upward by twice darkening amount */ |
343 | flatFamilyEdge += 2 * font->darkenY; /* bottom edge */ |
344 | |
345 | diff = cf2_fixedAbs( SUB_INT32( flatEdge, flatFamilyEdge ) ); |
346 | |
347 | if ( diff < minDiff && diff < csUnitsPerPixel ) |
348 | { |
349 | blues->zone[i].csFlatEdge = flatFamilyEdge; |
350 | minDiff = diff; |
351 | |
352 | if ( diff == 0 ) |
353 | break; |
354 | } |
355 | } |
356 | } |
357 | } |
358 | |
359 | /* TODO: enforce separation of zones, including BlueFuzz */ |
360 | |
361 | /* Adjust BlueScale; similar to AdjustBlueScale() in coretype */ |
362 | /* `bcsetup.c'. */ |
363 | |
364 | if ( maxZoneHeight > 0 ) |
365 | { |
366 | if ( blues->blueScale > FT_DivFix( cf2_intToFixed( 1 ), |
367 | maxZoneHeight ) ) |
368 | { |
369 | /* clamp at maximum scale */ |
370 | blues->blueScale = FT_DivFix( cf2_intToFixed( 1 ), |
371 | maxZoneHeight ); |
372 | } |
373 | |
374 | /* |
375 | * TODO: Revisit the bug fix for 613448. The minimum scale |
376 | * requirement catches a number of library fonts. For |
377 | * example, with default BlueScale (.039625) and 0.4 minimum, |
378 | * the test below catches any font with maxZoneHeight < 10.1. |
379 | * There are library fonts ranging from 2 to 10 that get |
380 | * caught, including e.g., Eurostile LT Std Medium with |
381 | * maxZoneHeight of 6. |
382 | * |
383 | */ |
384 | #if 0 |
385 | if ( blueScale < .4 / maxZoneHeight ) |
386 | { |
387 | tetraphilia_assert( 0 ); |
388 | /* clamp at minimum scale, per bug 0613448 fix */ |
389 | blueScale = .4 / maxZoneHeight; |
390 | } |
391 | #endif |
392 | |
393 | } |
394 | |
395 | /* |
396 | * Suppress overshoot and boost blue zones at small sizes. Boost |
397 | * amount varies linearly from 0.5 pixel near 0 to 0 pixel at |
398 | * blueScale cutoff. |
399 | * Note: This boost amount is different from the coretype heuristic. |
400 | * |
401 | */ |
402 | |
403 | if ( blues->scale < blues->blueScale ) |
404 | { |
405 | blues->suppressOvershoot = TRUE; |
406 | |
407 | /* Change rounding threshold for `dsFlatEdge'. */ |
408 | /* Note: constant changed from 0.5 to 0.6 to avoid a problem with */ |
409 | /* 10ppem Arial */ |
410 | |
411 | blues->boost = cf2_doubleToFixed( .6 ) - |
412 | FT_MulDiv( cf2_doubleToFixed ( .6 ), |
413 | blues->scale, |
414 | blues->blueScale ); |
415 | if ( blues->boost > 0x7FFF ) |
416 | { |
417 | /* boost must remain less than 0.5, or baseline could go negative */ |
418 | blues->boost = 0x7FFF; |
419 | } |
420 | } |
421 | |
422 | /* boost and darkening have similar effects; don't do both */ |
423 | if ( font->stemDarkened ) |
424 | blues->boost = 0; |
425 | |
426 | /* set device space alignment for each zone; */ |
427 | /* apply boost amount before rounding flat edge */ |
428 | |
429 | for ( i = 0; i < blues->count; i++ ) |
430 | { |
431 | if ( blues->zone[i].bottomZone ) |
432 | blues->zone[i].dsFlatEdge = cf2_fixedRound( |
433 | FT_MulFix( |
434 | blues->zone[i].csFlatEdge, |
435 | blues->scale ) - |
436 | blues->boost ); |
437 | else |
438 | blues->zone[i].dsFlatEdge = cf2_fixedRound( |
439 | FT_MulFix( |
440 | blues->zone[i].csFlatEdge, |
441 | blues->scale ) + |
442 | blues->boost ); |
443 | } |
444 | } |
445 | |
446 | |
447 | /* |
448 | * Check whether `stemHint' is captured by one of the blue zones. |
449 | * |
450 | * Zero, one or both edges may be valid; only valid edges can be |
451 | * captured. For compatibility with CoolType, search top and bottom |
452 | * zones in the same pass (see `BlueLock'). If a hint is captured, |
453 | * return true and position the edge(s) in one of 3 ways: |
454 | * |
455 | * 1) If `BlueScale' suppresses overshoot, position the captured edge |
456 | * at the flat edge of the zone. |
457 | * 2) If overshoot is not suppressed and `BlueShift' requires |
458 | * overshoot, position the captured edge a minimum of 1 device pixel |
459 | * from the flat edge. |
460 | * 3) If overshoot is not suppressed or required, position the captured |
461 | * edge at the nearest device pixel. |
462 | * |
463 | */ |
464 | FT_LOCAL_DEF( FT_Bool ) |
465 | cf2_blues_capture( const CF2_Blues blues, |
466 | CF2_Hint bottomHintEdge, |
467 | CF2_Hint topHintEdge ) |
468 | { |
469 | /* TODO: validate? */ |
470 | CF2_Fixed csFuzz = blues->blueFuzz; |
471 | |
472 | /* new position of captured edge */ |
473 | CF2_Fixed dsNew; |
474 | |
475 | /* amount that hint is moved when positioned */ |
476 | CF2_Fixed dsMove = 0; |
477 | |
478 | FT_Bool captured = FALSE; |
479 | CF2_UInt i; |
480 | |
481 | |
482 | /* assert edge flags are consistent */ |
483 | FT_ASSERT( !cf2_hint_isTop( bottomHintEdge ) && |
484 | !cf2_hint_isBottom( topHintEdge ) ); |
485 | |
486 | /* TODO: search once without blue fuzz for compatibility with coretype? */ |
487 | for ( i = 0; i < blues->count; i++ ) |
488 | { |
489 | if ( blues->zone[i].bottomZone && |
490 | cf2_hint_isBottom( bottomHintEdge ) ) |
491 | { |
492 | if ( SUB_INT32( blues->zone[i].csBottomEdge, csFuzz ) <= |
493 | bottomHintEdge->csCoord && |
494 | bottomHintEdge->csCoord <= |
495 | ADD_INT32( blues->zone[i].csTopEdge, csFuzz ) ) |
496 | { |
497 | /* bottom edge captured by bottom zone */ |
498 | |
499 | if ( blues->suppressOvershoot ) |
500 | dsNew = blues->zone[i].dsFlatEdge; |
501 | |
502 | else if ( SUB_INT32( blues->zone[i].csTopEdge, |
503 | bottomHintEdge->csCoord ) >= |
504 | blues->blueShift ) |
505 | { |
506 | /* guarantee minimum of 1 pixel overshoot */ |
507 | dsNew = FT_MIN( |
508 | cf2_fixedRound( bottomHintEdge->dsCoord ), |
509 | SUB_INT32( blues->zone[i].dsFlatEdge, |
510 | cf2_intToFixed( 1 ) ) ); |
511 | } |
512 | |
513 | else |
514 | { |
515 | /* simply round captured edge */ |
516 | dsNew = cf2_fixedRound( bottomHintEdge->dsCoord ); |
517 | } |
518 | |
519 | dsMove = SUB_INT32( dsNew, bottomHintEdge->dsCoord ); |
520 | captured = TRUE; |
521 | |
522 | break; |
523 | } |
524 | } |
525 | |
526 | if ( !blues->zone[i].bottomZone && cf2_hint_isTop( topHintEdge ) ) |
527 | { |
528 | if ( SUB_INT32( blues->zone[i].csBottomEdge, csFuzz ) <= |
529 | topHintEdge->csCoord && |
530 | topHintEdge->csCoord <= |
531 | ADD_INT32( blues->zone[i].csTopEdge, csFuzz ) ) |
532 | { |
533 | /* top edge captured by top zone */ |
534 | |
535 | if ( blues->suppressOvershoot ) |
536 | dsNew = blues->zone[i].dsFlatEdge; |
537 | |
538 | else if ( SUB_INT32( topHintEdge->csCoord, |
539 | blues->zone[i].csBottomEdge ) >= |
540 | blues->blueShift ) |
541 | { |
542 | /* guarantee minimum of 1 pixel overshoot */ |
543 | dsNew = FT_MAX( |
544 | cf2_fixedRound( topHintEdge->dsCoord ), |
545 | blues->zone[i].dsFlatEdge + cf2_intToFixed( 1 ) ); |
546 | } |
547 | |
548 | else |
549 | { |
550 | /* simply round captured edge */ |
551 | dsNew = cf2_fixedRound( topHintEdge->dsCoord ); |
552 | } |
553 | |
554 | dsMove = SUB_INT32( dsNew, topHintEdge->dsCoord ); |
555 | captured = TRUE; |
556 | |
557 | break; |
558 | } |
559 | } |
560 | } |
561 | |
562 | if ( captured ) |
563 | { |
564 | /* move both edges and flag them `locked' */ |
565 | if ( cf2_hint_isValid( bottomHintEdge ) ) |
566 | { |
567 | bottomHintEdge->dsCoord = ADD_INT32( bottomHintEdge->dsCoord, |
568 | dsMove ); |
569 | cf2_hint_lock( bottomHintEdge ); |
570 | } |
571 | |
572 | if ( cf2_hint_isValid( topHintEdge ) ) |
573 | { |
574 | topHintEdge->dsCoord = ADD_INT32( topHintEdge->dsCoord, dsMove ); |
575 | cf2_hint_lock( topHintEdge ); |
576 | } |
577 | } |
578 | |
579 | return captured; |
580 | } |
581 | |
582 | |
583 | /* END */ |
584 | |