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+/***************************************************************************/
+/* */
+/* 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 )
+ {
+ /* Internal calculations are done in units per thousand for */
+ /* convenience. */
+ 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 )
+ {
+ /* 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( 2333 );
+ }
+ else
+ {
+ scaledStem = FT_MulFix( stemWidthPer1000, ppem );
+
+ if ( ppem > CF2_FIXED_ONE &&
+ scaledStem <= stemWidthPer1000 )
+ scaledStem = cf2_intToFixed( 2333 );
+ }
+
+ /*
+ * 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 ) );
+
+ /* 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;
+
+ 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 = 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 = 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 = 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 );
+ }
+ else
+ cf2_computeDarkening( emRatio,
+ ppem,
+ font->stdVW,
+ &font->darkenX,
+ 0,
+ font->stemDarkened );
+
+#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 );
+
+ 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_getGlyphWidth( 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;
+ 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 );
+
+ /* FreeType just wants the advance width; there is no translation */
+ *glyphWidth = advWidth;
+
+ /* free resources and collect errors from objects we've used */
+ exit:
+ cf2_setError( &font->error, lastError );
+
+ return font->error;
+ }
+
+
+/* END */
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