ref: 768022b98e45d343b540f83816fb65f549eac041
dir: /src/psaux/psblues.c/
/**************************************************************************** * * psblues.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 * license to make, have made, use, offer to sell, sell, import, and * otherwise transfer the Work, where such license applies only to those * patent claims licensable by such contributor that are necessarily * infringed by their contribution(s) alone or by combination of their * contribution(s) with the Work to which such contribution(s) was * submitted. If You institute patent litigation against any entity * (including a cross-claim or counterclaim in a lawsuit) alleging that * the Work or a contribution incorporated within the Work constitutes * direct or contributory patent infringement, then any patent licenses * granted to You under this License for that Work shall terminate as of * the date such litigation is filed. * * By using, modifying, or distributing the Work you indicate that you * have read and understood the terms and conditions of the * FreeType Project License as well as those provided in this section, * and you accept them fully. * */ #include "psft.h" #include <freetype/internal/ftdebug.h> #include "psblues.h" #include "pshints.h" #include "psfont.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 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 */ PS_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 = SUB_INT32( 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 = SUB_INT32( 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( SUB_INT32( 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( SUB_INT32( 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( SUB_INT32( 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_doubleToFixed( .6 ) - FT_MulDiv( cf2_doubleToFixed ( .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 ( SUB_INT32( blues->zone[i].csBottomEdge, csFuzz ) <= bottomHintEdge->csCoord && bottomHintEdge->csCoord <= ADD_INT32( blues->zone[i].csTopEdge, csFuzz ) ) { /* bottom edge captured by bottom zone */ if ( blues->suppressOvershoot ) dsNew = blues->zone[i].dsFlatEdge; else if ( SUB_INT32( 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 = SUB_INT32( dsNew, bottomHintEdge->dsCoord ); captured = TRUE; break; } } if ( !blues->zone[i].bottomZone && cf2_hint_isTop( topHintEdge ) ) { if ( SUB_INT32( blues->zone[i].csBottomEdge, csFuzz ) <= topHintEdge->csCoord && topHintEdge->csCoord <= ADD_INT32( blues->zone[i].csTopEdge, csFuzz ) ) { /* top edge captured by top zone */ if ( blues->suppressOvershoot ) dsNew = blues->zone[i].dsFlatEdge; else if ( SUB_INT32( 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 = SUB_INT32( dsNew, topHintEdge->dsCoord ); captured = TRUE; break; } } } if ( captured ) { /* move both edges and flag them `locked' */ if ( cf2_hint_isValid( bottomHintEdge ) ) { bottomHintEdge->dsCoord = ADD_INT32( bottomHintEdge->dsCoord, dsMove ); cf2_hint_lock( bottomHintEdge ); } if ( cf2_hint_isValid( topHintEdge ) ) { topHintEdge->dsCoord = ADD_INT32( topHintEdge->dsCoord, dsMove ); cf2_hint_lock( topHintEdge ); } } return captured; } /* END */