/***************************************************************************/ | |
/* */ | |
/* cf2font.c */ | |
/* */ | |
/* Adobe's code for font instances (body). */ | |
/* */ | |
/* Copyright 2007-2014 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, */ | |
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/* */ | |
/***************************************************************************/ | |
#include <ft2build.h> | |
#include FT_INTERNAL_CALC_H | |
#include "cf2ft.h" | |
#include "cf2glue.h" | |
#include "cf2font.h" | |
#include "cf2error.h" | |
#include "cf2intrp.h" | |
/* Compute a stem darkening amount in character space. */ | |
static void | |
cf2_computeDarkening( CF2_Fixed emRatio, | |
CF2_Fixed ppem, | |
CF2_Fixed stemWidth, | |
CF2_Fixed* darkenAmount, | |
CF2_Fixed boldenAmount, | |
FT_Bool stemDarkened, | |
FT_Int* darkenParams ) | |
{ | |
/* | |
* Total darkening amount is computed in 1000 unit character space | |
* using the modified 5 part curve as Adobe's Avalon rasterizer. | |
* The darkening amount is smaller for thicker stems. | |
* It becomes zero when the stem is thicker than 2.333 pixels. | |
* | |
* By default, we use | |
* | |
* darkenAmount = 0.4 pixels if scaledStem <= 0.5 pixels, | |
* darkenAmount = 0.275 pixels if 1 <= scaledStem <= 1.667 pixels, | |
* darkenAmount = 0 pixel if scaledStem >= 2.333 pixels, | |
* | |
* and piecewise linear in-between: | |
* | |
* | |
* darkening | |
* ^ | |
* | | |
* | (x1,y1) | |
* |--------+ | |
* | \ | |
* | \ | |
* | \ (x3,y3) | |
* | +----------+ | |
* | (x2,y2) \ | |
* | \ | |
* | \ | |
* | +----------------- | |
* | (x4,y4) | |
* +---------------------------------------------> stem | |
* thickness | |
* | |
* | |
* This corresponds to the following values for the | |
* `darkening-parameters' property: | |
* | |
* (x1, y1) = (500, 400) | |
* (x2, y2) = (1000, 275) | |
* (x3, y3) = (1667, 275) | |
* (x4, y4) = (2333, 0) | |
* | |
*/ | |
/* Internal calculations are done in units per thousand for */ | |
/* convenience. The x axis is scaled stem width in */ | |
/* thousandths of a pixel. That is, 1000 is 1 pixel. */ | |
/* The y axis is darkening amount in thousandths of a pixel.*/ | |
/* In the code, below, dividing by ppem and */ | |
/* adjusting for emRatio converts darkenAmount to character */ | |
/* space (font units). */ | |
CF2_Fixed stemWidthPer1000, scaledStem; | |
FT_Int logBase2; | |
*darkenAmount = 0; | |
if ( boldenAmount == 0 && !stemDarkened ) | |
return; | |
/* protect against range problems and divide by zero */ | |
if ( emRatio < cf2_floatToFixed( .01 ) ) | |
return; | |
if ( stemDarkened ) | |
{ | |
FT_Int x1 = darkenParams[0]; | |
FT_Int y1 = darkenParams[1]; | |
FT_Int x2 = darkenParams[2]; | |
FT_Int y2 = darkenParams[3]; | |
FT_Int x3 = darkenParams[4]; | |
FT_Int y3 = darkenParams[5]; | |
FT_Int x4 = darkenParams[6]; | |
FT_Int y4 = darkenParams[7]; | |
/* convert from true character space to 1000 unit character space; */ | |
/* add synthetic emboldening effect */ | |
/* `stemWidthPer1000' will not overflow for a legitimate font */ | |
stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio ); | |
/* `scaledStem' can easily overflow, so we must clamp its maximum */ | |
/* value; the test doesn't need to be precise, but must be */ | |
/* conservative. The clamp value (default 2333) where */ | |
/* `darkenAmount' is zero is well below the overflow value of */ | |
/* 32767. */ | |
/* */ | |
/* FT_MSB computes the integer part of the base 2 logarithm. The */ | |
/* number of bits for the product is 1 or 2 more than the sum of */ | |
/* logarithms; remembering that the 16 lowest bits of the fraction */ | |
/* are dropped this is correct to within a factor of almost 4. */ | |
/* For example, 0x80.0000 * 0x80.0000 = 0x4000.0000 is 23+23 and */ | |
/* is flagged as possible overflow because 0xFF.FFFF * 0xFF.FFFF = */ | |
/* 0xFFFF.FE00 is also 23+23. */ | |
logBase2 = FT_MSB( (FT_UInt32)stemWidthPer1000 ) + | |
FT_MSB( (FT_UInt32)ppem ); | |
if ( logBase2 >= 46 ) | |
/* possible overflow */ | |
scaledStem = cf2_intToFixed( x4 ); | |
else | |
scaledStem = FT_MulFix( stemWidthPer1000, ppem ); | |
/* now apply the darkening parameters */ | |
if ( scaledStem < cf2_intToFixed( x1 ) ) | |
*darkenAmount = FT_DivFix( cf2_intToFixed( y1 ), ppem ); | |
else if ( scaledStem < cf2_intToFixed( x2 ) ) | |
{ | |
FT_Int xdelta = x2 - x1; | |
FT_Int ydelta = y2 - y1; | |
FT_Int x = stemWidthPer1000 - | |
FT_DivFix( cf2_intToFixed( x1 ), ppem ); | |
if ( !xdelta ) | |
goto Try_x3; | |
*darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + | |
FT_DivFix( cf2_intToFixed( y1 ), ppem ); | |
} | |
else if ( scaledStem < cf2_intToFixed( x3 ) ) | |
{ | |
Try_x3: | |
{ | |
FT_Int xdelta = x3 - x2; | |
FT_Int ydelta = y3 - y2; | |
FT_Int x = stemWidthPer1000 - | |
FT_DivFix( cf2_intToFixed( x2 ), ppem ); | |
if ( !xdelta ) | |
goto Try_x4; | |
*darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + | |
FT_DivFix( cf2_intToFixed( y2 ), ppem ); | |
} | |
} | |
else if ( scaledStem < cf2_intToFixed( x4 ) ) | |
{ | |
Try_x4: | |
{ | |
FT_Int xdelta = x4 - x3; | |
FT_Int ydelta = y4 - y3; | |
FT_Int x = stemWidthPer1000 - | |
FT_DivFix( cf2_intToFixed( x3 ), ppem ); | |
if ( !xdelta ) | |
goto Use_y4; | |
*darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + | |
FT_DivFix( cf2_intToFixed( y3 ), ppem ); | |
} | |
} | |
else | |
{ | |
Use_y4: | |
*darkenAmount = FT_DivFix( cf2_intToFixed( y4 ), ppem ); | |
} | |
/* use half the amount on each side and convert back to true */ | |
/* character space */ | |
*darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio ); | |
} | |
/* add synthetic emboldening effect in character space */ | |
*darkenAmount += boldenAmount / 2; | |
} | |
/* set up values for the current FontDict and matrix */ | |
/* caller's transform is adjusted for subpixel positioning */ | |
static void | |
cf2_font_setup( CF2_Font font, | |
const CF2_Matrix* transform ) | |
{ | |
/* pointer to parsed font object */ | |
CFF_Decoder* decoder = font->decoder; | |
FT_Bool needExtraSetup = FALSE; | |
/* character space units */ | |
CF2_Fixed boldenX = font->syntheticEmboldeningAmountX; | |
CF2_Fixed boldenY = font->syntheticEmboldeningAmountY; | |
CFF_SubFont subFont; | |
CF2_Fixed ppem; | |
/* clear previous error */ | |
font->error = FT_Err_Ok; | |
/* if a CID fontDict has changed, we need to recompute some cached */ | |
/* data */ | |
subFont = cf2_getSubfont( decoder ); | |
if ( font->lastSubfont != subFont ) | |
{ | |
font->lastSubfont = subFont; | |
needExtraSetup = TRUE; | |
} | |
/* if ppem has changed, we need to recompute some cached data */ | |
/* note: because of CID font matrix concatenation, ppem and transform */ | |
/* do not necessarily track. */ | |
ppem = cf2_getPpemY( decoder ); | |
if ( font->ppem != ppem ) | |
{ | |
font->ppem = ppem; | |
needExtraSetup = TRUE; | |
} | |
/* copy hinted flag on each call */ | |
font->hinted = (FT_Bool)( font->renderingFlags & CF2_FlagsHinted ); | |
/* determine if transform has changed; */ | |
/* include Fontmatrix but ignore translation */ | |
if ( ft_memcmp( transform, | |
&font->currentTransform, | |
4 * sizeof ( CF2_Fixed ) ) != 0 ) | |
{ | |
/* save `key' information for `cache of one' matrix data; */ | |
/* save client transform, without the translation */ | |
font->currentTransform = *transform; | |
font->currentTransform.tx = | |
font->currentTransform.ty = cf2_intToFixed( 0 ); | |
/* TODO: FreeType transform is simple scalar; for now, use identity */ | |
/* for outer */ | |
font->innerTransform = *transform; | |
font->outerTransform.a = | |
font->outerTransform.d = cf2_intToFixed( 1 ); | |
font->outerTransform.b = | |
font->outerTransform.c = cf2_intToFixed( 0 ); | |
needExtraSetup = TRUE; | |
} | |
/* | |
* font->darkened is set to true if there is a stem darkening request or | |
* the font is synthetic emboldened. | |
* font->darkened controls whether to adjust blue zones, winding order, | |
* and hinting. | |
* | |
*/ | |
if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) ) | |
{ | |
font->stemDarkened = | |
(FT_Bool)( font->renderingFlags & CF2_FlagsDarkened ); | |
/* blue zones depend on darkened flag */ | |
needExtraSetup = TRUE; | |
} | |
/* recompute variables that are dependent on transform or FontDict or */ | |
/* darken flag */ | |
if ( needExtraSetup ) | |
{ | |
/* StdVW is found in the private dictionary; */ | |
/* recompute darkening amounts whenever private dictionary or */ | |
/* transform change */ | |
/* Note: a rendering flag turns darkening on or off, so we want to */ | |
/* store the `on' amounts; */ | |
/* darkening amount is computed in character space */ | |
/* TODO: testing size-dependent darkening here; */ | |
/* what to do for rotations? */ | |
CF2_Fixed emRatio; | |
CF2_Fixed stdHW; | |
CF2_Int unitsPerEm = font->unitsPerEm; | |
if ( unitsPerEm == 0 ) | |
unitsPerEm = 1000; | |
ppem = FT_MAX( cf2_intToFixed( 4 ), | |
font->ppem ); /* use minimum ppem of 4 */ | |
#if 0 | |
/* since vstem is measured in the x-direction, we use the `a' member */ | |
/* of the fontMatrix */ | |
emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a ); | |
#endif | |
/* Freetype does not preserve the fontMatrix when parsing; use */ | |
/* unitsPerEm instead. */ | |
/* TODO: check precision of this */ | |
emRatio = cf2_intToFixed( 1000 ) / unitsPerEm; | |
font->stdVW = cf2_getStdVW( decoder ); | |
if ( font->stdVW <= 0 ) | |
font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); | |
if ( boldenX > 0 ) | |
{ | |
/* Ensure that boldenX is at least 1 pixel for synthetic bold font */ | |
/* (similar to what Avalon does) */ | |
boldenX = FT_MAX( boldenX, | |
FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) ); | |
/* Synthetic emboldening adds at least 1 pixel to darkenX, while */ | |
/* stem darkening adds at most half pixel. Since the purpose of */ | |
/* stem darkening (readability at small sizes) is met with */ | |
/* synthetic emboldening, no need to add stem darkening for a */ | |
/* synthetic bold font. */ | |
cf2_computeDarkening( emRatio, | |
ppem, | |
font->stdVW, | |
&font->darkenX, | |
boldenX, | |
FALSE, | |
font->darkenParams ); | |
} | |
else | |
cf2_computeDarkening( emRatio, | |
ppem, | |
font->stdVW, | |
&font->darkenX, | |
0, | |
font->stemDarkened, | |
font->darkenParams ); | |
#if 0 | |
/* since hstem is measured in the y-direction, we use the `d' member */ | |
/* of the fontMatrix */ | |
/* TODO: use the same units per em as above; check this */ | |
emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d ); | |
#endif | |
/* set the default stem width, because it must be the same for all */ | |
/* family members; */ | |
/* choose a constant for StdHW that depends on font contrast */ | |
stdHW = cf2_getStdHW( decoder ); | |
if ( stdHW > 0 && font->stdVW > 2 * stdHW ) | |
font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); | |
else | |
{ | |
/* low contrast font gets less hstem darkening */ | |
font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio ); | |
} | |
cf2_computeDarkening( emRatio, | |
ppem, | |
font->stdHW, | |
&font->darkenY, | |
boldenY, | |
font->stemDarkened, | |
font->darkenParams ); | |
if ( font->darkenX != 0 || font->darkenY != 0 ) | |
font->darkened = TRUE; | |
else | |
font->darkened = FALSE; | |
font->reverseWinding = FALSE; /* initial expectation is CCW */ | |
/* compute blue zones for this instance */ | |
cf2_blues_init( &font->blues, font ); | |
} | |
} | |
/* equivalent to AdobeGetOutline */ | |
FT_LOCAL_DEF( FT_Error ) | |
cf2_getGlyphOutline( CF2_Font font, | |
CF2_Buffer charstring, | |
const CF2_Matrix* transform, | |
CF2_F16Dot16* glyphWidth ) | |
{ | |
FT_Error lastError = FT_Err_Ok; | |
FT_Vector translation; | |
#if 0 | |
FT_Vector advancePoint; | |
#endif | |
CF2_Fixed advWidth = 0; | |
FT_Bool needWinding; | |
/* Note: use both integer and fraction for outlines. This allows bbox */ | |
/* to come out directly. */ | |
translation.x = transform->tx; | |
translation.y = transform->ty; | |
/* set up values based on transform */ | |
cf2_font_setup( font, transform ); | |
if ( font->error ) | |
goto exit; /* setup encountered an error */ | |
/* reset darken direction */ | |
font->reverseWinding = FALSE; | |
/* winding order only affects darkening */ | |
needWinding = font->darkened; | |
while ( 1 ) | |
{ | |
/* reset output buffer */ | |
cf2_outline_reset( &font->outline ); | |
/* build the outline, passing the full translation */ | |
cf2_interpT2CharString( font, | |
charstring, | |
(CF2_OutlineCallbacks)&font->outline, | |
&translation, | |
FALSE, | |
0, | |
0, | |
&advWidth ); | |
if ( font->error ) | |
goto exit; | |
if ( !needWinding ) | |
break; | |
/* check winding order */ | |
if ( font->outline.root.windingMomentum >= 0 ) /* CFF is CCW */ | |
break; | |
/* invert darkening and render again */ | |
/* TODO: this should be a parameter to getOutline-computeOffset */ | |
font->reverseWinding = TRUE; | |
needWinding = FALSE; /* exit after next iteration */ | |
} | |
/* finish storing client outline */ | |
cf2_outline_close( &font->outline ); | |
exit: | |
/* FreeType just wants the advance width; there is no translation */ | |
*glyphWidth = advWidth; | |
/* free resources and collect errors from objects we've used */ | |
cf2_setError( &font->error, lastError ); | |
return font->error; | |
} | |
/* END */ |