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Issue 815103002: Update freetype to 2.5.4. (Closed) Base URL: https://pdfium.googlesource.com/pdfium.git@master
Patch Set: Adjust GYP and GN Created 6 years ago
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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 */
14 /* FreeType Project License, each contributor to the Work hereby grants */
15 /* to any individual or legal entity exercising permissions granted by */
16 /* the FreeType Project License and this section (hereafter, "You" or */
17 /* "Your") a perpetual, worldwide, non-exclusive, no-charge, */
18 /* royalty-free, irrevocable (except as stated in this section) patent */
19 /* license to make, have made, use, offer to sell, sell, import, and */
20 /* otherwise transfer the Work, where such license applies only to those */
21 /* patent claims licensable by such contributor that are necessarily */
22 /* infringed by their contribution(s) alone or by combination of their */
23 /* contribution(s) with the Work to which such contribution(s) was */
24 /* submitted. If You institute patent litigation against any entity */
25 /* (including a cross-claim or counterclaim in a lawsuit) alleging that */
26 /* the Work or a contribution incorporated within the Work constitutes */
27 /* direct or contributory patent infringement, then any patent licenses */
28 /* granted to You under this License for that Work shall terminate as of */
29 /* the date such litigation is filed. */
30 /* */
31 /* By using, modifying, or distributing the Work you indicate that you */
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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