Commit 03ee7c82a3fc5c923b83cc26525f498786fee933
2005-09-23T14:14:15
* 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 !
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140
diff --git a/ChangeLog b/ChangeLog
index acbfc52..ee9b787 100644
--- 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 <wl@gnu.org>
* docs/CHANGES: Mention SING Glyphlet support.
diff --git a/src/autofit/afangles.c b/src/autofit/afangles.c
index 7411be7..dfb7bf7 100644
--- 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 @@ for n in r:
return v.y;
}
+#endif /* 0 */
FT_LOCAL_DEF( AF_Angle )
af_angle_diff( AF_Angle angle1,