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kc3-lang/freetype/src/cff/cf2font.c
Dave Arnold
- src/cff/cf2font.c
-
/***************************************************************************/ /* */ /* cf2font.c */ /* */ /* Adobe's code for font instances (body). */ /* */ /* Copyright 2007-2013 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 "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; *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 */ /* we have to assure that the computation of `scaledStem' */ /* and `stemWidthPer1000' don't overflow */ stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio ); if ( emRatio > CF2_FIXED_ONE && stemWidthPer1000 <= ( stemWidth + boldenAmount ) ) { stemWidthPer1000 = 0; /* to pacify compiler */ scaledStem = cf2_intToFixed( x4 ); } else { scaledStem = FT_MulFix( stemWidthPer1000, ppem ); if ( ppem > CF2_FIXED_ONE && scaledStem <= stemWidthPer1000 ) scaledStem = cf2_intToFixed( x4 ); } /* 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_MulFix( x, FT_DivFix( 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_MulFix( x, FT_DivFix( 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_MulFix( x, FT_DivFix( 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; /* character space units */ CF2_Fixed boldenX = font->syntheticEmboldeningAmountX; CF2_Fixed boldenY = font->syntheticEmboldeningAmountY; CF2_Fixed ppem; /* clear previous error */ font->error = FT_Err_Ok; /* if a CID fontDict has changed, we need to recompute some cached */ /* data */ needExtraSetup = (FT_Bool)( font->lastSubfont != cf2_getSubfont( decoder ) ); /* 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 */