1 /***************************************************************************/
5 /* Adobe's code for handling Blue Zones (body). */
7 /* Copyright 2009-2014 Adobe Systems Incorporated. */
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 /***************************************************************************/
40 #include FT_INTERNAL_DEBUG_H
47 /*************************************************************************/
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. */
54 #define FT_COMPONENT trace_cf2blues
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.
62 #define cf2_blueToFixed( x ) cf2_intToFixed( x )
66 cf2_blues_init( CF2_Blues blues
,
69 /* pointer to parsed font object */
70 CFF_Decoder
* decoder
= font
->decoder
;
73 CF2_Fixed maxZoneHeight
= 0;
74 CF2_Fixed csUnitsPerPixel
;
78 size_t numFamilyBlues
;
79 size_t numFamilyOtherBlues
;
84 FT_Pos
* familyOtherBlues
;
87 CF2_Fixed emBoxBottom
, emBoxTop
;
90 CF2_Int unitsPerEm
= font
->unitsPerEm
;
93 if ( unitsPerEm
== 0 )
98 blues
->scale
= font
->innerTransform
.d
;
100 cf2_getBlueMetrics( decoder
,
105 cf2_getBlueValues( decoder
, &numBlueValues
, &blueValues
);
106 cf2_getOtherBlues( decoder
, &numOtherBlues
, &otherBlues
);
107 cf2_getFamilyBlues( decoder
, &numFamilyBlues
, &familyBlues
);
108 cf2_getFamilyOtherBlues( decoder
, &numFamilyOtherBlues
, &familyOtherBlues
);
111 * synthetic em box hint heuristic
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.
121 /* get em box from OS/2 typoAscender/Descender */
122 /* TODO: FreeType does not parse these metrics. Skip them for now. */
124 FCM_getHorizontalLineMetrics( &e
,
129 if ( ascender
- descender
== unitsPerEm
)
131 emBoxBottom
= cf2_intToFixed( descender
);
132 emBoxTop
= cf2_intToFixed( ascender
);
137 emBoxBottom
= CF2_ICF_Bottom
;
138 emBoxTop
= CF2_ICF_Top
;
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
) ) )
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.
155 * Note: Adjust synthetic hints outward by epsilon (0x.0001) to
156 * avoid interference. E.g., some fonts have real hints at
160 blues
->emBoxBottomEdge
.csCoord
= emBoxBottom
- CF2_FIXED_EPSILON
;
161 blues
->emBoxBottomEdge
.dsCoord
= cf2_fixedRound(
163 blues
->emBoxBottomEdge
.csCoord
,
166 blues
->emBoxBottomEdge
.scale
= blues
->scale
;
167 blues
->emBoxBottomEdge
.flags
= CF2_GhostBottom
|
171 blues
->emBoxTopEdge
.csCoord
= emBoxTop
+ CF2_FIXED_EPSILON
+
173 blues
->emBoxTopEdge
.dsCoord
= cf2_fixedRound(
175 blues
->emBoxTopEdge
.csCoord
,
178 blues
->emBoxTopEdge
.scale
= blues
->scale
;
179 blues
->emBoxTopEdge
.flags
= CF2_GhostTop
|
183 blues
->doEmBoxHints
= TRUE
; /* enable the heuristic */
188 /* copy `BlueValues' and `OtherBlues' to a combined array of top and */
190 for ( i
= 0; i
< numBlueValues
; i
+= 2 )
192 blues
->zone
[blues
->count
].csBottomEdge
=
193 cf2_blueToFixed( blueValues
[i
] );
194 blues
->zone
[blues
->count
].csTopEdge
=
195 cf2_blueToFixed( blueValues
[i
+ 1] );
197 zoneHeight
= blues
->zone
[blues
->count
].csTopEdge
-
198 blues
->zone
[blues
->count
].csBottomEdge
;
200 if ( zoneHeight
< 0 )
202 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" ));
203 continue; /* reject this zone */
206 if ( zoneHeight
> maxZoneHeight
)
208 /* take maximum before darkening adjustment */
209 /* so overshoot suppression point doesn't change */
210 maxZoneHeight
= zoneHeight
;
213 /* adjust both edges of top zone upward by twice darkening amount */
216 blues
->zone
[blues
->count
].csTopEdge
+= 2 * font
->darkenY
;
217 blues
->zone
[blues
->count
].csBottomEdge
+= 2 * font
->darkenY
;
220 /* first `BlueValue' is bottom zone; others are top */
223 blues
->zone
[blues
->count
].bottomZone
=
225 blues
->zone
[blues
->count
].csFlatEdge
=
226 blues
->zone
[blues
->count
].csTopEdge
;
230 blues
->zone
[blues
->count
].bottomZone
=
232 blues
->zone
[blues
->count
].csFlatEdge
=
233 blues
->zone
[blues
->count
].csBottomEdge
;
239 for ( i
= 0; i
< numOtherBlues
; i
+= 2 )
241 blues
->zone
[blues
->count
].csBottomEdge
=
242 cf2_blueToFixed( otherBlues
[i
] );
243 blues
->zone
[blues
->count
].csTopEdge
=
244 cf2_blueToFixed( otherBlues
[i
+ 1] );
246 zoneHeight
= blues
->zone
[blues
->count
].csTopEdge
-
247 blues
->zone
[blues
->count
].csBottomEdge
;
249 if ( zoneHeight
< 0 )
251 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" ));
252 continue; /* reject this zone */
255 if ( zoneHeight
> maxZoneHeight
)
257 /* take maximum before darkening adjustment */
258 /* so overshoot suppression point doesn't change */
259 maxZoneHeight
= zoneHeight
;
262 /* Note: bottom zones are not adjusted for darkening amount */
264 /* all OtherBlues are bottom zone */
265 blues
->zone
[blues
->count
].bottomZone
=
267 blues
->zone
[blues
->count
].csFlatEdge
=
268 blues
->zone
[blues
->count
].csTopEdge
;
273 /* Adjust for FamilyBlues */
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 */
279 csUnitsPerPixel
= FT_DivFix( cf2_intToFixed( 1 ), blues
->scale
);
281 /* loop on all zones in this font */
282 for ( i
= 0; i
< blues
->count
; i
++ )
286 CF2_Fixed flatFamilyEdge
, diff
;
287 /* value for this font */
288 CF2_Fixed flatEdge
= blues
->zone
[i
].csFlatEdge
;
291 if ( blues
->zone
[i
].bottomZone
)
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. */
297 minDiff
= CF2_FIXED_MAX
;
299 for ( j
= 0; j
< numFamilyOtherBlues
; j
+= 2 )
302 flatFamilyEdge
= cf2_blueToFixed( familyOtherBlues
[j
+ 1] );
304 diff
= cf2_fixedAbs( flatEdge
- flatFamilyEdge
);
306 if ( diff
< minDiff
&& diff
< csUnitsPerPixel
)
308 blues
->zone
[i
].csFlatEdge
= flatFamilyEdge
;
316 /* check the first member of FamilyBlues, which is a bottom zone */
317 if ( numFamilyBlues
>= 2 )
320 flatFamilyEdge
= cf2_blueToFixed( familyBlues
[1] );
322 diff
= cf2_fixedAbs( flatEdge
- flatFamilyEdge
);
324 if ( diff
< minDiff
&& diff
< csUnitsPerPixel
)
325 blues
->zone
[i
].csFlatEdge
= flatFamilyEdge
;
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 */
335 minDiff
= CF2_FIXED_MAX
;
337 for ( j
= 2; j
< numFamilyBlues
; j
+= 2 )
340 flatFamilyEdge
= cf2_blueToFixed( familyBlues
[j
] );
342 /* adjust edges of top zone upward by twice darkening amount */
343 flatFamilyEdge
+= 2 * font
->darkenY
; /* bottom edge */
345 diff
= cf2_fixedAbs( flatEdge
- flatFamilyEdge
);
347 if ( diff
< minDiff
&& diff
< csUnitsPerPixel
)
349 blues
->zone
[i
].csFlatEdge
= flatFamilyEdge
;
359 /* TODO: enforce separation of zones, including BlueFuzz */
361 /* Adjust BlueScale; similar to AdjustBlueScale() in coretype */
364 if ( maxZoneHeight
> 0 )
366 if ( blues
->blueScale
> FT_DivFix( cf2_intToFixed( 1 ),
369 /* clamp at maximum scale */
370 blues
->blueScale
= FT_DivFix( cf2_intToFixed( 1 ),
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.
385 if ( blueScale
< .4 / maxZoneHeight
)
387 tetraphilia_assert( 0 );
388 /* clamp at minimum scale, per bug 0613448 fix */
389 blueScale
= .4 / maxZoneHeight
;
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
399 * Note: This boost amount is different from the coretype heuristic.
403 if ( blues
->scale
< blues
->blueScale
)
405 blues
->suppressOvershoot
= TRUE
;
407 /* Change rounding threshold for `dsFlatEdge'. */
408 /* Note: constant changed from 0.5 to 0.6 to avoid a problem with */
411 blues
->boost
= cf2_floatToFixed( .6 ) -
412 FT_MulDiv( cf2_floatToFixed ( .6 ),
415 if ( blues
->boost
> 0x7FFF )
417 /* boost must remain less than 0.5, or baseline could go negative */
418 blues
->boost
= 0x7FFF;
422 /* boost and darkening have similar effects; don't do both */
423 if ( font
->stemDarkened
)
426 /* set device space alignment for each zone; */
427 /* apply boost amount before rounding flat edge */
429 for ( i
= 0; i
< blues
->count
; i
++ )
431 if ( blues
->zone
[i
].bottomZone
)
432 blues
->zone
[i
].dsFlatEdge
= cf2_fixedRound(
434 blues
->zone
[i
].csFlatEdge
,
438 blues
->zone
[i
].dsFlatEdge
= cf2_fixedRound(
440 blues
->zone
[i
].csFlatEdge
,
448 * Check whether `stemHint' is captured by one of the blue zones.
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:
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.
464 FT_LOCAL_DEF( FT_Bool
)
465 cf2_blues_capture( const CF2_Blues blues
,
466 CF2_Hint bottomHintEdge
,
467 CF2_Hint topHintEdge
)
469 /* TODO: validate? */
470 CF2_Fixed csFuzz
= blues
->blueFuzz
;
472 /* new position of captured edge */
475 /* amount that hint is moved when positioned */
476 CF2_Fixed dsMove
= 0;
478 FT_Bool captured
= FALSE
;
482 /* assert edge flags are consistent */
483 FT_ASSERT( !cf2_hint_isTop( bottomHintEdge
) &&
484 !cf2_hint_isBottom( topHintEdge
) );
486 /* TODO: search once without blue fuzz for compatibility with coretype? */
487 for ( i
= 0; i
< blues
->count
; i
++ )
489 if ( blues
->zone
[i
].bottomZone
&&
490 cf2_hint_isBottom( bottomHintEdge
) )
492 if ( ( blues
->zone
[i
].csBottomEdge
- csFuzz
) <=
493 bottomHintEdge
->csCoord
&&
494 bottomHintEdge
->csCoord
<=
495 ( blues
->zone
[i
].csTopEdge
+ csFuzz
) )
497 /* bottom edge captured by bottom zone */
499 if ( blues
->suppressOvershoot
)
500 dsNew
= blues
->zone
[i
].dsFlatEdge
;
502 else if ( ( blues
->zone
[i
].csTopEdge
- bottomHintEdge
->csCoord
) >=
505 /* guarantee minimum of 1 pixel overshoot */
507 cf2_fixedRound( bottomHintEdge
->dsCoord
),
508 blues
->zone
[i
].dsFlatEdge
- cf2_intToFixed( 1 ) );
513 /* simply round captured edge */
514 dsNew
= cf2_fixedRound( bottomHintEdge
->dsCoord
);
517 dsMove
= dsNew
- bottomHintEdge
->dsCoord
;
524 if ( !blues
->zone
[i
].bottomZone
&& cf2_hint_isTop( topHintEdge
) )
526 if ( ( blues
->zone
[i
].csBottomEdge
- csFuzz
) <=
527 topHintEdge
->csCoord
&&
528 topHintEdge
->csCoord
<=
529 ( blues
->zone
[i
].csTopEdge
+ csFuzz
) )
531 /* top edge captured by top zone */
533 if ( blues
->suppressOvershoot
)
534 dsNew
= blues
->zone
[i
].dsFlatEdge
;
536 else if ( ( topHintEdge
->csCoord
- blues
->zone
[i
].csBottomEdge
) >=
539 /* guarantee minimum of 1 pixel overshoot */
541 cf2_fixedRound( topHintEdge
->dsCoord
),
542 blues
->zone
[i
].dsFlatEdge
+ cf2_intToFixed( 1 ) );
547 /* simply round captured edge */
548 dsNew
= cf2_fixedRound( topHintEdge
->dsCoord
);
551 dsMove
= dsNew
- topHintEdge
->dsCoord
;
561 /* move both edges and flag them `locked' */
562 if ( cf2_hint_isValid( bottomHintEdge
) )
564 bottomHintEdge
->dsCoord
+= dsMove
;
565 cf2_hint_lock( bottomHintEdge
);
568 if ( cf2_hint_isValid( topHintEdge
) )
570 topHintEdge
->dsCoord
+= dsMove
;
571 cf2_hint_lock( topHintEdge
);