ref: 03ee7c82a3fc5c923b83cc26525f498786fee933
parent: 18e44430ae30835bc5136208834fbac4920fbea5
author: David Turner <[email protected]>
date: Fri Sep 23 10:14:15 EDT 2005
* src/autofit/afangles.c (af_angle_atan): replaced CORDIC-based
implementation with one using lookup tables. This simple thing
speeds glyph loading by 18% according to ftbench !
--- a/ChangeLog
+++ b/ChangeLog
@@ -15,6 +15,11 @@
removing _many_ compiler warnings when compiling with Visual C++
at maximum level (/W4)
+ * src/autofit/afangles.c (af_angle_atan): replaced CORDIC-based
+ implementation with one using lookup tables. This simple thing
+ speeds glyph loading by 18% according to ftbench !
+
+
2005-09-22 Werner Lemberg <[email protected]>
* docs/CHANGES: Mention SING Glyphlet support.
--- a/src/autofit/afangles.c
+++ b/src/autofit/afangles.c
@@ -20,6 +20,111 @@
#include "aftypes.h"
+#if 1
+
+ /* the following table has been automatically generated with */
+ /* the `mather.py' Python script */
+
+#define AF_ATAN_BITS 8
+
+ static const FT_Byte af_arctan[1L << AF_ATAN_BITS] =
+ {+ 0, 0, 1, 1, 1, 2, 2, 2,
+ 3, 3, 3, 3, 4, 4, 4, 5,
+ 5, 5, 6, 6, 6, 7, 7, 7,
+ 8, 8, 8, 9, 9, 9, 10, 10,
+ 10, 10, 11, 11, 11, 12, 12, 12,
+ 13, 13, 13, 14, 14, 14, 14, 15,
+ 15, 15, 16, 16, 16, 17, 17, 17,
+ 18, 18, 18, 18, 19, 19, 19, 20,
+ 20, 20, 21, 21, 21, 21, 22, 22,
+ 22, 23, 23, 23, 24, 24, 24, 24,
+ 25, 25, 25, 26, 26, 26, 26, 27,
+ 27, 27, 28, 28, 28, 28, 29, 29,
+ 29, 30, 30, 30, 30, 31, 31, 31,
+ 31, 32, 32, 32, 33, 33, 33, 33,
+ 34, 34, 34, 34, 35, 35, 35, 35,
+ 36, 36, 36, 36, 37, 37, 37, 38,
+ 38, 38, 38, 39, 39, 39, 39, 40,
+ 40, 40, 40, 41, 41, 41, 41, 42,
+ 42, 42, 42, 42, 43, 43, 43, 43,
+ 44, 44, 44, 44, 45, 45, 45, 45,
+ 46, 46, 46, 46, 46, 47, 47, 47,
+ 47, 48, 48, 48, 48, 48, 49, 49,
+ 49, 49, 50, 50, 50, 50, 50, 51,
+ 51, 51, 51, 51, 52, 52, 52, 52,
+ 52, 53, 53, 53, 53, 53, 54, 54,
+ 54, 54, 54, 55, 55, 55, 55, 55,
+ 56, 56, 56, 56, 56, 57, 57, 57,
+ 57, 57, 57, 58, 58, 58, 58, 58,
+ 59, 59, 59, 59, 59, 59, 60, 60,
+ 60, 60, 60, 61, 61, 61, 61, 61,
+ 61, 62, 62, 62, 62, 62, 62, 63,
+ 63, 63, 63, 63, 63, 64, 64, 64
+ };
+
+
+ FT_LOCAL_DEF( AF_Angle )
+ af_angle_atan( FT_Fixed dx,
+ FT_Fixed dy )
+ {+ AF_Angle angle;
+
+
+ /* check trivial cases */
+ if ( dy == 0 )
+ {+ angle = 0;
+ if ( dx < 0 )
+ angle = AF_ANGLE_PI;
+ return angle;
+ }
+ else if ( dx == 0 )
+ {+ angle = AF_ANGLE_PI2;
+ if ( dy < 0 )
+ angle = -AF_ANGLE_PI2;
+ return angle;
+ }
+
+ angle = 0;
+ if ( dx < 0 )
+ {+ dx = -dx;
+ dy = -dy;
+ angle = AF_ANGLE_PI;
+ }
+
+ if ( dy < 0 )
+ {+ FT_Pos tmp;
+
+
+ tmp = dx;
+ dx = -dy;
+ dy = tmp;
+ angle -= AF_ANGLE_PI2;
+ }
+
+ if ( dx == 0 && dy == 0 )
+ return 0;
+
+ if ( dx == dy )
+ angle += AF_ANGLE_PI4;
+ else if ( dx > dy )
+ angle += af_arctan[FT_DivFix( dy, dx ) >> ( 16 - AF_ATAN_BITS )];
+ else
+ angle += AF_ANGLE_PI2 -
+ af_arctan[FT_DivFix( dx, dy ) >> ( 16 - AF_ATAN_BITS )];
+
+ if ( angle > AF_ANGLE_PI )
+ angle -= AF_ANGLE_2PI;
+
+ return angle;
+ }
+
+
+#else /* 0 */
/*
* a python script used to generate the following table
*
@@ -216,6 +321,7 @@
return v.y;
}
+#endif /* 0 */
FT_LOCAL_DEF( AF_Angle )
af_angle_diff( AF_Angle angle1,