diff options
Diffstat (limited to 'src/cff/cf2font.c')
| -rw-r--r-- | src/cff/cf2font.c | 175 |
1 files changed, 135 insertions, 40 deletions
diff --git a/src/cff/cf2font.c b/src/cff/cf2font.c index 8b2331d..718d1e2 100644 --- a/src/cff/cf2font.c +++ b/src/cff/cf2font.c @@ -51,10 +51,59 @@ CF2_Fixed stemWidth, CF2_Fixed* darkenAmount, CF2_Fixed boldenAmount, - FT_Bool stemDarkened ) + 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. */ + /* 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; @@ -69,6 +118,16 @@ 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 */ @@ -81,7 +140,7 @@ stemWidthPer1000 <= ( stemWidth + boldenAmount ) ) { stemWidthPer1000 = 0; /* to pacify compiler */ - scaledStem = cf2_intToFixed( 2333 ); + scaledStem = cf2_intToFixed( x4 ); } else { @@ -89,39 +148,70 @@ if ( ppem > CF2_FIXED_ONE && scaledStem <= stemWidthPer1000 ) - scaledStem = cf2_intToFixed( 2333 ); + 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 ); + } } - /* - * Total darkening amount is computed in 1000 unit character space - * using the modified 5 part curve as Avalon rasterizer. - * The darkening amount is smaller for thicker stems. - * It becomes zero when the stem is thicker than 2.333 pixels. - * - * In Avalon rasterizer, - * - * darkenAmount = 0.5 pixels if scaledStem <= 0.5 pixels, - * darkenAmount = 0.333 pixels if 1 <= scaledStem <= 1.667 pixels, - * darkenAmount = 0 pixel if scaledStem >= 2.333 pixels, - * - * and piecewise linear in-between. - * - */ - if ( scaledStem < cf2_intToFixed( 500 ) ) - *darkenAmount = FT_DivFix( cf2_intToFixed( 400 ), ppem ); - - else if ( scaledStem < cf2_intToFixed( 1000 ) ) - *darkenAmount = FT_DivFix( cf2_intToFixed( 525 ), ppem ) - - FT_MulFix( stemWidthPer1000, - cf2_floatToFixed( .25 ) ); - - else if ( scaledStem < cf2_intToFixed( 1667 ) ) - *darkenAmount = FT_DivFix( cf2_intToFixed( 275 ), ppem ); - - else if ( scaledStem < cf2_intToFixed( 2333 ) ) - *darkenAmount = FT_DivFix( cf2_intToFixed( 963 ), ppem ) - - FT_MulFix( stemWidthPer1000, - cf2_floatToFixed( .413 ) ); + 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 */ @@ -157,7 +247,8 @@ /* if a CID fontDict has changed, we need to recompute some cached */ /* data */ - needExtraSetup = font->lastSubfont != cf2_getSubfont( decoder ); + 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 */ @@ -170,7 +261,7 @@ } /* copy hinted flag on each call */ - font->hinted = font->renderingFlags & CF2_FlagsHinted; + font->hinted = (FT_Bool)( font->renderingFlags & CF2_FlagsHinted ); /* determine if transform has changed; */ /* include Fontmatrix but ignore translation */ @@ -204,7 +295,8 @@ */ if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) ) { - font->stemDarkened = font->renderingFlags & CF2_FlagsDarkened; + font->stemDarkened = + (FT_Bool)( font->renderingFlags & CF2_FlagsDarkened ); /* blue zones depend on darkened flag */ needExtraSetup = TRUE; @@ -266,7 +358,8 @@ font->stdVW, &font->darkenX, boldenX, - FALSE ); + FALSE, + font->darkenParams ); } else cf2_computeDarkening( emRatio, @@ -274,7 +367,8 @@ font->stdVW, &font->darkenX, 0, - font->stemDarkened ); + font->stemDarkened, + font->darkenParams ); #if 0 /* since hstem is measured in the y-direction, we use the `d' member */ @@ -301,7 +395,8 @@ font->stdHW, &font->darkenY, boldenY, - font->stemDarkened ); + font->stemDarkened, + font->darkenParams ); if ( font->darkenX != 0 || font->darkenY != 0 ) font->darkened = TRUE; |