/***************************************************************************/ | |
/* */ | |
/* cf2blues.c */ | |
/* */ | |
/* Adobe's code for handling Blue Zones (body). */ | |
/* */ | |
/* Copyright 2009-2014 Adobe Systems Incorporated. */ | |
/* */ | |
/* This software, and all works of authorship, whether in source or */ | |
/* object code form as indicated by the copyright notice(s) included */ | |
/* herein (collectively, the "Work") is made available, and may only be */ | |
/* used, modified, and distributed under the FreeType Project License, */ | |
/* LICENSE.TXT. Additionally, subject to the terms and conditions of the */ | |
/* FreeType Project License, each contributor to the Work hereby grants */ | |
/* to any individual or legal entity exercising permissions granted by */ | |
/* the FreeType Project License and this section (hereafter, "You" or */ | |
/* "Your") a perpetual, worldwide, non-exclusive, no-charge, */ | |
/* royalty-free, irrevocable (except as stated in this section) patent */ | |
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/* patent claims licensable by such contributor that are necessarily */ | |
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/* */ | |
/***************************************************************************/ | |
#include "cf2ft.h" | |
#include FT_INTERNAL_DEBUG_H | |
#include "cf2blues.h" | |
#include "cf2hints.h" | |
#include "cf2font.h" | |
/*************************************************************************/ | |
/* */ | |
/* The macro FT_COMPONENT is used in trace mode. It is an implicit */ | |
/* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ | |
/* messages during execution. */ | |
/* */ | |
#undef FT_COMPONENT | |
#define FT_COMPONENT trace_cf2blues | |
/* | |
* For blue values, the FreeType parser produces an array of integers, | |
* while the Adobe CFF engine produces an array of fixed. | |
* Define a macro to convert FreeType to fixed. | |
*/ | |
#define cf2_blueToFixed( x ) cf2_intToFixed( x ) | |
FT_LOCAL_DEF( void ) | |
cf2_blues_init( CF2_Blues blues, | |
CF2_Font font ) | |
{ | |
/* pointer to parsed font object */ | |
CFF_Decoder* decoder = font->decoder; | |
CF2_Fixed zoneHeight; | |
CF2_Fixed maxZoneHeight = 0; | |
CF2_Fixed csUnitsPerPixel; | |
size_t numBlueValues; | |
size_t numOtherBlues; | |
size_t numFamilyBlues; | |
size_t numFamilyOtherBlues; | |
FT_Pos* blueValues; | |
FT_Pos* otherBlues; | |
FT_Pos* familyBlues; | |
FT_Pos* familyOtherBlues; | |
size_t i; | |
CF2_Fixed emBoxBottom, emBoxTop; | |
#if 0 | |
CF2_Int unitsPerEm = font->unitsPerEm; | |
if ( unitsPerEm == 0 ) | |
unitsPerEm = 1000; | |
#endif | |
FT_ZERO( blues ); | |
blues->scale = font->innerTransform.d; | |
cf2_getBlueMetrics( decoder, | |
&blues->blueScale, | |
&blues->blueShift, | |
&blues->blueFuzz ); | |
cf2_getBlueValues( decoder, &numBlueValues, &blueValues ); | |
cf2_getOtherBlues( decoder, &numOtherBlues, &otherBlues ); | |
cf2_getFamilyBlues( decoder, &numFamilyBlues, &familyBlues ); | |
cf2_getFamilyOtherBlues( decoder, &numFamilyOtherBlues, &familyOtherBlues ); | |
/* | |
* synthetic em box hint heuristic | |
* | |
* Apply this when ideographic dictionary (LanguageGroup 1) has no | |
* real alignment zones. Adobe tools generate dummy zones at -250 and | |
* 1100 for a 1000 unit em. Fonts with ICF-based alignment zones | |
* should not enable the heuristic. When the heuristic is enabled, | |
* the font's blue zones are ignored. | |
* | |
*/ | |
/* get em box from OS/2 typoAscender/Descender */ | |
/* TODO: FreeType does not parse these metrics. Skip them for now. */ | |
#if 0 | |
FCM_getHorizontalLineMetrics( &e, | |
font->font, | |
&ascender, | |
&descender, | |
&linegap ); | |
if ( ascender - descender == unitsPerEm ) | |
{ | |
emBoxBottom = cf2_intToFixed( descender ); | |
emBoxTop = cf2_intToFixed( ascender ); | |
} | |
else | |
#endif | |
{ | |
emBoxBottom = CF2_ICF_Bottom; | |
emBoxTop = CF2_ICF_Top; | |
} | |
if ( cf2_getLanguageGroup( decoder ) == 1 && | |
( numBlueValues == 0 || | |
( numBlueValues == 4 && | |
cf2_blueToFixed( blueValues[0] ) < emBoxBottom && | |
cf2_blueToFixed( blueValues[1] ) < emBoxBottom && | |
cf2_blueToFixed( blueValues[2] ) > emBoxTop && | |
cf2_blueToFixed( blueValues[3] ) > emBoxTop ) ) ) | |
{ | |
/* | |
* Construct hint edges suitable for synthetic ghost hints at top | |
* and bottom of em box. +-CF2_MIN_COUNTER allows for unhinted | |
* features above or below the last hinted edge. This also gives a | |
* net 1 pixel boost to the height of ideographic glyphs. | |
* | |
* Note: Adjust synthetic hints outward by epsilon (0x.0001) to | |
* avoid interference. E.g., some fonts have real hints at | |
* 880 and -120. | |
*/ | |
blues->emBoxBottomEdge.csCoord = emBoxBottom - CF2_FIXED_EPSILON; | |
blues->emBoxBottomEdge.dsCoord = cf2_fixedRound( | |
FT_MulFix( | |
blues->emBoxBottomEdge.csCoord, | |
blues->scale ) ) - | |
CF2_MIN_COUNTER; | |
blues->emBoxBottomEdge.scale = blues->scale; | |
blues->emBoxBottomEdge.flags = CF2_GhostBottom | | |
CF2_Locked | | |
CF2_Synthetic; | |
blues->emBoxTopEdge.csCoord = emBoxTop + CF2_FIXED_EPSILON + | |
2 * font->darkenY; | |
blues->emBoxTopEdge.dsCoord = cf2_fixedRound( | |
FT_MulFix( | |
blues->emBoxTopEdge.csCoord, | |
blues->scale ) ) + | |
CF2_MIN_COUNTER; | |
blues->emBoxTopEdge.scale = blues->scale; | |
blues->emBoxTopEdge.flags = CF2_GhostTop | | |
CF2_Locked | | |
CF2_Synthetic; | |
blues->doEmBoxHints = TRUE; /* enable the heuristic */ | |
return; | |
} | |
/* copy `BlueValues' and `OtherBlues' to a combined array of top and */ | |
/* bottom zones */ | |
for ( i = 0; i < numBlueValues; i += 2 ) | |
{ | |
blues->zone[blues->count].csBottomEdge = | |
cf2_blueToFixed( blueValues[i] ); | |
blues->zone[blues->count].csTopEdge = | |
cf2_blueToFixed( blueValues[i + 1] ); | |
zoneHeight = blues->zone[blues->count].csTopEdge - | |
blues->zone[blues->count].csBottomEdge; | |
if ( zoneHeight < 0 ) | |
{ | |
FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); | |
continue; /* reject this zone */ | |
} | |
if ( zoneHeight > maxZoneHeight ) | |
{ | |
/* take maximum before darkening adjustment */ | |
/* so overshoot suppression point doesn't change */ | |
maxZoneHeight = zoneHeight; | |
} | |
/* adjust both edges of top zone upward by twice darkening amount */ | |
if ( i != 0 ) | |
{ | |
blues->zone[blues->count].csTopEdge += 2 * font->darkenY; | |
blues->zone[blues->count].csBottomEdge += 2 * font->darkenY; | |
} | |
/* first `BlueValue' is bottom zone; others are top */ | |
if ( i == 0 ) | |
{ | |
blues->zone[blues->count].bottomZone = | |
TRUE; | |
blues->zone[blues->count].csFlatEdge = | |
blues->zone[blues->count].csTopEdge; | |
} | |
else | |
{ | |
blues->zone[blues->count].bottomZone = | |
FALSE; | |
blues->zone[blues->count].csFlatEdge = | |
blues->zone[blues->count].csBottomEdge; | |
} | |
blues->count += 1; | |
} | |
for ( i = 0; i < numOtherBlues; i += 2 ) | |
{ | |
blues->zone[blues->count].csBottomEdge = | |
cf2_blueToFixed( otherBlues[i] ); | |
blues->zone[blues->count].csTopEdge = | |
cf2_blueToFixed( otherBlues[i + 1] ); | |
zoneHeight = blues->zone[blues->count].csTopEdge - | |
blues->zone[blues->count].csBottomEdge; | |
if ( zoneHeight < 0 ) | |
{ | |
FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); | |
continue; /* reject this zone */ | |
} | |
if ( zoneHeight > maxZoneHeight ) | |
{ | |
/* take maximum before darkening adjustment */ | |
/* so overshoot suppression point doesn't change */ | |
maxZoneHeight = zoneHeight; | |
} | |
/* Note: bottom zones are not adjusted for darkening amount */ | |
/* all OtherBlues are bottom zone */ | |
blues->zone[blues->count].bottomZone = | |
TRUE; | |
blues->zone[blues->count].csFlatEdge = | |
blues->zone[blues->count].csTopEdge; | |
blues->count += 1; | |
} | |
/* Adjust for FamilyBlues */ | |
/* Search for the nearest flat edge in `FamilyBlues' or */ | |
/* `FamilyOtherBlues'. According to the Black Book, any matching edge */ | |
/* must be within one device pixel */ | |
csUnitsPerPixel = FT_DivFix( cf2_intToFixed( 1 ), blues->scale ); | |
/* loop on all zones in this font */ | |
for ( i = 0; i < blues->count; i++ ) | |
{ | |
size_t j; | |
CF2_Fixed minDiff; | |
CF2_Fixed flatFamilyEdge, diff; | |
/* value for this font */ | |
CF2_Fixed flatEdge = blues->zone[i].csFlatEdge; | |
if ( blues->zone[i].bottomZone ) | |
{ | |
/* In a bottom zone, the top edge is the flat edge. */ | |
/* Search `FamilyOtherBlues' for bottom zones; look for closest */ | |
/* Family edge that is within the one pixel threshold. */ | |
minDiff = CF2_FIXED_MAX; | |
for ( j = 0; j < numFamilyOtherBlues; j += 2 ) | |
{ | |
/* top edge */ | |
flatFamilyEdge = cf2_blueToFixed( familyOtherBlues[j + 1] ); | |
diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); | |
if ( diff < minDiff && diff < csUnitsPerPixel ) | |
{ | |
blues->zone[i].csFlatEdge = flatFamilyEdge; | |
minDiff = diff; | |
if ( diff == 0 ) | |
break; | |
} | |
} | |
/* check the first member of FamilyBlues, which is a bottom zone */ | |
if ( numFamilyBlues >= 2 ) | |
{ | |
/* top edge */ | |
flatFamilyEdge = cf2_blueToFixed( familyBlues[1] ); | |
diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); | |
if ( diff < minDiff && diff < csUnitsPerPixel ) | |
blues->zone[i].csFlatEdge = flatFamilyEdge; | |
} | |
} | |
else | |
{ | |
/* In a top zone, the bottom edge is the flat edge. */ | |
/* Search `FamilyBlues' for top zones; skip first zone, which is a */ | |
/* bottom zone; look for closest Family edge that is within the */ | |
/* one pixel threshold */ | |
minDiff = CF2_FIXED_MAX; | |
for ( j = 2; j < numFamilyBlues; j += 2 ) | |
{ | |
/* bottom edge */ | |
flatFamilyEdge = cf2_blueToFixed( familyBlues[j] ); | |
/* adjust edges of top zone upward by twice darkening amount */ | |
flatFamilyEdge += 2 * font->darkenY; /* bottom edge */ | |
diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); | |
if ( diff < minDiff && diff < csUnitsPerPixel ) | |
{ | |
blues->zone[i].csFlatEdge = flatFamilyEdge; | |
minDiff = diff; | |
if ( diff == 0 ) | |
break; | |
} | |
} | |
} | |
} | |
/* TODO: enforce separation of zones, including BlueFuzz */ | |
/* Adjust BlueScale; similar to AdjustBlueScale() in coretype */ | |
/* `bcsetup.c'. */ | |
if ( maxZoneHeight > 0 ) | |
{ | |
if ( blues->blueScale > FT_DivFix( cf2_intToFixed( 1 ), | |
maxZoneHeight ) ) | |
{ | |
/* clamp at maximum scale */ | |
blues->blueScale = FT_DivFix( cf2_intToFixed( 1 ), | |
maxZoneHeight ); | |
} | |
/* | |
* TODO: Revisit the bug fix for 613448. The minimum scale | |
* requirement catches a number of library fonts. For | |
* example, with default BlueScale (.039625) and 0.4 minimum, | |
* the test below catches any font with maxZoneHeight < 10.1. | |
* There are library fonts ranging from 2 to 10 that get | |
* caught, including e.g., Eurostile LT Std Medium with | |
* maxZoneHeight of 6. | |
* | |
*/ | |
#if 0 | |
if ( blueScale < .4 / maxZoneHeight ) | |
{ | |
tetraphilia_assert( 0 ); | |
/* clamp at minimum scale, per bug 0613448 fix */ | |
blueScale = .4 / maxZoneHeight; | |
} | |
#endif | |
} | |
/* | |
* Suppress overshoot and boost blue zones at small sizes. Boost | |
* amount varies linearly from 0.5 pixel near 0 to 0 pixel at | |
* blueScale cutoff. | |
* Note: This boost amount is different from the coretype heuristic. | |
* | |
*/ | |
if ( blues->scale < blues->blueScale ) | |
{ | |
blues->suppressOvershoot = TRUE; | |
/* Change rounding threshold for `dsFlatEdge'. */ | |
/* Note: constant changed from 0.5 to 0.6 to avoid a problem with */ | |
/* 10ppem Arial */ | |
blues->boost = cf2_floatToFixed( .6 ) - | |
FT_MulDiv( cf2_floatToFixed ( .6 ), | |
blues->scale, | |
blues->blueScale ); | |
if ( blues->boost > 0x7FFF ) | |
{ | |
/* boost must remain less than 0.5, or baseline could go negative */ | |
blues->boost = 0x7FFF; | |
} | |
} | |
/* boost and darkening have similar effects; don't do both */ | |
if ( font->stemDarkened ) | |
blues->boost = 0; | |
/* set device space alignment for each zone; */ | |
/* apply boost amount before rounding flat edge */ | |
for ( i = 0; i < blues->count; i++ ) | |
{ | |
if ( blues->zone[i].bottomZone ) | |
blues->zone[i].dsFlatEdge = cf2_fixedRound( | |
FT_MulFix( | |
blues->zone[i].csFlatEdge, | |
blues->scale ) - | |
blues->boost ); | |
else | |
blues->zone[i].dsFlatEdge = cf2_fixedRound( | |
FT_MulFix( | |
blues->zone[i].csFlatEdge, | |
blues->scale ) + | |
blues->boost ); | |
} | |
} | |
/* | |
* Check whether `stemHint' is captured by one of the blue zones. | |
* | |
* Zero, one or both edges may be valid; only valid edges can be | |
* captured. For compatibility with CoolType, search top and bottom | |
* zones in the same pass (see `BlueLock'). If a hint is captured, | |
* return true and position the edge(s) in one of 3 ways: | |
* | |
* 1) If `BlueScale' suppresses overshoot, position the captured edge | |
* at the flat edge of the zone. | |
* 2) If overshoot is not suppressed and `BlueShift' requires | |
* overshoot, position the captured edge a minimum of 1 device pixel | |
* from the flat edge. | |
* 3) If overshoot is not suppressed or required, position the captured | |
* edge at the nearest device pixel. | |
* | |
*/ | |
FT_LOCAL_DEF( FT_Bool ) | |
cf2_blues_capture( const CF2_Blues blues, | |
CF2_Hint bottomHintEdge, | |
CF2_Hint topHintEdge ) | |
{ | |
/* TODO: validate? */ | |
CF2_Fixed csFuzz = blues->blueFuzz; | |
/* new position of captured edge */ | |
CF2_Fixed dsNew; | |
/* amount that hint is moved when positioned */ | |
CF2_Fixed dsMove = 0; | |
FT_Bool captured = FALSE; | |
CF2_UInt i; | |
/* assert edge flags are consistent */ | |
FT_ASSERT( !cf2_hint_isTop( bottomHintEdge ) && | |
!cf2_hint_isBottom( topHintEdge ) ); | |
/* TODO: search once without blue fuzz for compatibility with coretype? */ | |
for ( i = 0; i < blues->count; i++ ) | |
{ | |
if ( blues->zone[i].bottomZone && | |
cf2_hint_isBottom( bottomHintEdge ) ) | |
{ | |
if ( ( blues->zone[i].csBottomEdge - csFuzz ) <= | |
bottomHintEdge->csCoord && | |
bottomHintEdge->csCoord <= | |
( blues->zone[i].csTopEdge + csFuzz ) ) | |
{ | |
/* bottom edge captured by bottom zone */ | |
if ( blues->suppressOvershoot ) | |
dsNew = blues->zone[i].dsFlatEdge; | |
else if ( ( blues->zone[i].csTopEdge - bottomHintEdge->csCoord ) >= | |
blues->blueShift ) | |
{ | |
/* guarantee minimum of 1 pixel overshoot */ | |
dsNew = FT_MIN( | |
cf2_fixedRound( bottomHintEdge->dsCoord ), | |
blues->zone[i].dsFlatEdge - cf2_intToFixed( 1 ) ); | |
} | |
else | |
{ | |
/* simply round captured edge */ | |
dsNew = cf2_fixedRound( bottomHintEdge->dsCoord ); | |
} | |
dsMove = dsNew - bottomHintEdge->dsCoord; | |
captured = TRUE; | |
break; | |
} | |
} | |
if ( !blues->zone[i].bottomZone && cf2_hint_isTop( topHintEdge ) ) | |
{ | |
if ( ( blues->zone[i].csBottomEdge - csFuzz ) <= | |
topHintEdge->csCoord && | |
topHintEdge->csCoord <= | |
( blues->zone[i].csTopEdge + csFuzz ) ) | |
{ | |
/* top edge captured by top zone */ | |
if ( blues->suppressOvershoot ) | |
dsNew = blues->zone[i].dsFlatEdge; | |
else if ( ( topHintEdge->csCoord - blues->zone[i].csBottomEdge ) >= | |
blues->blueShift ) | |
{ | |
/* guarantee minimum of 1 pixel overshoot */ | |
dsNew = FT_MAX( | |
cf2_fixedRound( topHintEdge->dsCoord ), | |
blues->zone[i].dsFlatEdge + cf2_intToFixed( 1 ) ); | |
} | |
else | |
{ | |
/* simply round captured edge */ | |
dsNew = cf2_fixedRound( topHintEdge->dsCoord ); | |
} | |
dsMove = dsNew - topHintEdge->dsCoord; | |
captured = TRUE; | |
break; | |
} | |
} | |
} | |
if ( captured ) | |
{ | |
/* move both edges and flag them `locked' */ | |
if ( cf2_hint_isValid( bottomHintEdge ) ) | |
{ | |
bottomHintEdge->dsCoord += dsMove; | |
cf2_hint_lock( bottomHintEdge ); | |
} | |
if ( cf2_hint_isValid( topHintEdge ) ) | |
{ | |
topHintEdge->dsCoord += dsMove; | |
cf2_hint_lock( topHintEdge ); | |
} | |
} | |
return captured; | |
} | |
/* END */ |