diff options
Diffstat (limited to 'src/raster/ftraster.c')
| -rw-r--r-- | src/raster/ftraster.c | 60 |
1 files changed, 48 insertions, 12 deletions
diff --git a/src/raster/ftraster.c b/src/raster/ftraster.c index ce6fdfe..55e2d0d 100644 --- a/src/raster/ftraster.c +++ b/src/raster/ftraster.c @@ -4,7 +4,7 @@ /* */ /* The FreeType glyph rasterizer (body). */ /* */ -/* Copyright 1996-2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010 by */ +/* Copyright 1996-2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010, 2011 by */ /* David Turner, Robert Wilhelm, and Werner Lemberg. */ /* */ /* This file is part of the FreeType project, and may only be used, */ @@ -302,7 +302,6 @@ typedef short Short; typedef unsigned short UShort, *PUShort; typedef long Long, *PLong; - typedef unsigned long ULong; typedef unsigned char Byte, *PByte; typedef char Bool; @@ -448,7 +447,6 @@ Int precision_bits; /* precision related variables */ Int precision; Int precision_half; - Long precision_mask; Int precision_shift; Int precision_step; Int precision_jitter; @@ -653,11 +651,33 @@ static void Set_High_Precision( RAS_ARGS Int High ) { + /* + * `precision_step' is used in `Bezier_Up' to decide when to split a + * given y-monotonous Bezier arc that crosses a scanline before + * approximating it as a straight segment. The default value of 32 (for + * low accuracy) corresponds to + * + * 32 / 64 == 0.5 pixels , + * + * while for the high accuracy case we have + * + * 256/ (1 << 12) = 0.0625 pixels . + * + * `precision_jitter' is an epsilon threshold used in + * `Vertical_Sweep_Span' to deal with small imperfections in the Bezier + * decomposition (after all, we are working with approximations only); + * it avoids switching on additional pixels which would cause artifacts + * otherwise. + * + * The value of `precision_jitter' has been determined heuristically. + * + */ + if ( High ) { ras.precision_bits = 12; ras.precision_step = 256; - ras.precision_jitter = 50; + ras.precision_jitter = 30; } else { @@ -671,7 +691,6 @@ ras.precision = 1 << ras.precision_bits; ras.precision_half = ras.precision / 2; ras.precision_shift = ras.precision_bits - Pixel_Bits; - ras.precision_mask = -ras.precision; } @@ -725,13 +744,13 @@ if ( overshoot ) ras.cProfile->flags |= Overshoot_Bottom; - FT_TRACE6(( "New ascending profile = %lx\n", (long)ras.cProfile )); + FT_TRACE6(( "New ascending profile = %p\n", ras.cProfile )); break; case Descending_State: if ( overshoot ) ras.cProfile->flags |= Overshoot_Top; - FT_TRACE6(( "New descending profile = %lx\n", (long)ras.cProfile )); + FT_TRACE6(( "New descending profile = %p\n", ras.cProfile )); break; default: @@ -784,8 +803,8 @@ if ( h > 0 ) { - FT_TRACE6(( "Ending profile %lx, start = %ld, height = %ld\n", - (long)ras.cProfile, ras.cProfile->start, h )); + FT_TRACE6(( "Ending profile %p, start = %ld, height = %ld\n", + ras.cProfile, ras.cProfile->start, h )); ras.cProfile->height = h; if ( overshoot ) @@ -1094,7 +1113,7 @@ return SUCCESS; else { - x1 += FMulDiv( Dx, ras.precision - f1, Dy ); + x1 += SMulDiv( Dx, ras.precision - f1, Dy ); e1 += 1; } } @@ -1122,13 +1141,13 @@ if ( Dx > 0 ) { - Ix = SMulDiv( ras.precision, Dx, Dy); + Ix = SMulDiv( ras.precision, Dx, Dy); Rx = ( ras.precision * Dx ) % Dy; Dx = 1; } else { - Ix = SMulDiv( ras.precision, -Dx, Dy) * -1; + Ix = SMulDiv( ras.precision, -Dx, Dy) * -1; Rx = ( ras.precision * -Dx ) % Dy; Dx = -1; } @@ -2406,6 +2425,14 @@ return; /* no drop-out control */ } + /* undocumented but confirmed: If the drop-out would result in a */ + /* pixel outside of the bounding box, use the pixel inside of the */ + /* bounding box instead */ + if ( pxl < 0 ) + pxl = e1; + else if ( TRUNC( pxl ) >= ras.bWidth ) + pxl = e2; + /* check that the other pixel isn't set */ e1 = pxl == e1 ? e2 : e1; @@ -2582,6 +2609,14 @@ return; /* no drop-out control */ } + /* undocumented but confirmed: If the drop-out would result in a */ + /* pixel outside of the bounding box, use the pixel inside of the */ + /* bounding box instead */ + if ( pxl < 0 ) + pxl = e1; + else if ( TRUNC( pxl ) >= ras.target.rows ) + pxl = e2; + /* check that the other pixel isn't set */ e1 = pxl == e1 ? e2 : e1; @@ -3385,6 +3420,7 @@ FT_Raster *araster ) { static TRaster the_raster; + FT_UNUSED( memory ); *araster = (FT_Raster)&the_raster; |