ref: 81473305d85d49658803680777a9f9528596f4a0
dir: /libfreetype/ahangles.c/
/***************************************************************************/
/* */
/* ahangles.h */
/* */
/* A routine used to compute vector angles with limited accuracy */
/* and very high speed (body). */
/* */
/* Copyright 2000-2001, 2002 Catharon Productions Inc. */
/* Author: David Turner */
/* */
/* This file is part of the Catharon Typography Project and shall only */
/* be used, modified, and distributed under the terms of the Catharon */
/* Open Source License that should come with this file under the name */
/* `CatharonLicense.txt'. By continuing to use, modify, or distribute */
/* this file you indicate that you have read the license and */
/* understand and accept it fully. */
/* */
/* Note that this license is compatible with the FreeType license. */
/* */
/***************************************************************************/
#include <ft2build.h>
#include "ahangles.h"
/* the following table has been automatically generated with */
/* the `mather.py' Python script */
const AH_Angle ah_arctan[1L << AH_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( AH_Angle )
ah_angle( FT_Vector* v )
{
FT_Pos dx, dy;
AH_Angle angle;
dx = v->x;
dy = v->y;
/* check trivial cases */
if ( dy == 0 )
{
angle = 0;
if ( dx < 0 )
angle = AH_PI;
return angle;
}
else if ( dx == 0 )
{
angle = AH_HALF_PI;
if ( dy < 0 )
angle = -AH_HALF_PI;
return angle;
}
angle = 0;
if ( dx < 0 )
{
dx = -v->x;
dy = -v->y;
angle = AH_PI;
}
if ( dy < 0 )
{
FT_Pos tmp;
tmp = dx;
dx = -dy;
dy = tmp;
angle -= AH_HALF_PI;
}
if ( dx == 0 && dy == 0 )
return 0;
if ( dx == dy )
angle += AH_PI / 4;
else if ( dx > dy )
angle += ah_arctan[FT_DivFix( dy, dx ) >> ( 16 - AH_ATAN_BITS )];
else
angle += AH_HALF_PI -
ah_arctan[FT_DivFix( dx, dy ) >> ( 16 - AH_ATAN_BITS )];
if ( angle > AH_PI )
angle -= AH_2PI;
return angle;
}
FT_LOCAL_DEF( AH_Angle )
ah_angle_diff( AH_Angle angle1,
AH_Angle angle2 )
{
AH_Angle delta;
delta = ( angle2 - angle1 );
if ( delta < 0 )
delta += AH_2PI;
if ( delta > AH_PI )
delta -= AH_2PI;
return delta;
}
/* END */