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* src/autofit/afangles.c (af_angle_atan): replaced CORDIC-based

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implementation with one using lookup tables. This simple thing
        speeds glyph loading by 18% according to ftbench !
This commit is contained in:
David Turner 2005-09-23 14:14:15 +00:00
parent 18e44430ae
commit 03ee7c82a3
2 changed files with 111 additions and 0 deletions
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5
ChangeLog
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@ -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.

106
src/autofit/afangles.c
View File

@ -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,