Commit adf07a930cb0ce44a57018a2c5edbc9ac8916d88
2001-10-30T23:51:24
* src/smooth/ftgrays.c: adding experimental "gamma" support. This produces smoother glyphs at small sizes for very little cost * src/autohint/ahglyph.c, src/autohint/ahhint.c: various fixes to the auto-hinter. They merely improve the output of sans-serif fonts. Note that there are still problems with serifed fonts and composites (accented characters) * tests/gview.c: updated the debugging glyph viewer to show the hints generated by the "autohint" module
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diff --git a/ChangeLog b/ChangeLog
index 1a3d575..e7c5239 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2001-10-29 David Turner <david@freetype.org>
+
+ * src/smooth/ftgrays.c: adding experimental "gamma" support. This
+ produces smoother glyphs at small sizes for very little cost
+
+ * src/autohint/ahglyph.c, src/autohint/ahhint.c: various fixes to
+ the auto-hinter. They merely improve the output of sans-serif fonts.
+ Note that there are still problems with serifed fonts and composites
+ (accented characters)
+
+ * tests/gview.c: updated the debugging glyph viewer to show the
+ hints generated by the "autohint" module
+
+
2001-10-27 David Turner <david@freetype.org>
* src/cache/ftchunk.c (ftc_chunk_cache_lookup): fixed a bug that
diff --git a/src/autohint/ahglyph.c b/src/autohint/ahglyph.c
index 667f830..5c2f4f7 100644
--- a/src/autohint/ahglyph.c
+++ b/src/autohint/ahglyph.c
@@ -994,7 +994,7 @@
dist = -dist;
if ( len < 8 )
- score = 300 + dist;
+ score = 300*8 + dist - len*3;
else
score = dist + 300/len;
diff --git a/src/autohint/ahhint.c b/src/autohint/ahhint.c
index 11ace9f..1dd003c 100644
--- a/src/autohint/ahhint.c
+++ b/src/autohint/ahhint.c
@@ -169,10 +169,12 @@
if ( base->flags & ah_edge_done )
{
if ( dist >= 64 )
- dist = ( dist + 8 ) & -64;
+ dist = (dist+8) & -64;
else if ( dist <= 32 && !vertical )
dist = ( dist + 33 ) >> 1;
+ else
+ dist = 0;
}
serif->pos = base->pos + sign * dist;
diff --git a/src/smooth/ftgrays.c b/src/smooth/ftgrays.c
index 54a814f..031a1d9 100644
--- a/src/smooth/ftgrays.c
+++ b/src/smooth/ftgrays.c
@@ -84,6 +84,10 @@
#include <string.h> /* for memcpy() */
#include <setjmp.h>
+
+/* experimental support for gamma correction within the rasterizer */
+#define GRAYS_USE_GAMMA
+
/*************************************************************************/
/* */
/* The macro FT_COMPONENT is used in trace mode. It is an implicit */
@@ -305,6 +309,10 @@
void* memory;
jmp_buf jump_buffer;
+#ifdef GRAYS_USE_GAMMA
+ FT_Byte gamma[257];
+#endif
+
} TRaster, *PRaster;
@@ -1230,15 +1238,21 @@
for ( ; count > 0; count--, spans++ )
{
- if ( spans->coverage )
+ FT_UInt coverage = spans->coverage;
+
+#ifdef GRAYS_USE_GAMMA
+ coverage = raster->gamma[(FT_Byte)coverage];
+#endif
+
+ if ( coverage )
#if 1
- MEM_Set( p + spans->x, (unsigned char)spans->coverage, spans->len );
+ MEM_Set( p + spans->x, (unsigned char)coverage, spans->len );
#else /* 1 */
{
q = p + spans->x;
limit = q + spans->len;
for ( ; q < limit; q++ )
- q[0] = (unsigned char)spans->coverage;
+ q[0] = (unsigned char)coverage;
}
#endif /* 1 */
}
@@ -1960,6 +1974,33 @@
/**** RASTER OBJECT CREATION: In standalone mode, we simply use *****/
/**** a static object. *****/
+#ifdef GRAYS_USE_GAMMA
+
+ /* initialize the "gamma" table. Yes, this is really a crummy function */
+ /* but the results look pretty good for something that simple.. */
+ /* */
+#define M_MAX 255
+#define M_X 128
+#define M_Y 96
+
+ static void
+ grays_init_gamma( PRaster raster )
+ {
+ FT_UInt x, a;
+
+ for ( x = 0; x < 256; x++ )
+ {
+ if ( x <= M_X )
+ a = (x * M_Y + (M_X/2)) / M_X;
+ else
+ a = M_Y + ((x-M_X)*(M_MAX-M_Y) + (M_MAX-M_X)/2)/(M_MAX-M_X);
+
+ raster->gamma[x] = (FT_Byte)a;
+ }
+ }
+
+#endif /* GRAYS_USE_GAMMA */
+
#ifdef _STANDALONE_
static int
@@ -1974,6 +2015,10 @@
*araster = (FT_Raster)&the_raster;
MEM_Set( &the_raster, 0, sizeof ( the_raster ) );
+#ifdef GRAYS_USE_GAMMA
+ grays_init_gamma( (PRaster)*araster );
+#endif
+
return 0;
}
@@ -2000,6 +2045,10 @@
{
raster->memory = memory;
*araster = (FT_Raster)raster;
+
+#ifdef GRAYS_USE_GAMMA
+ grays_init_gamma( raster );
+#endif
}
return error;