ref: c49f69cb8c9d9b38179f760bf0cbbe4c78a3e296
dir: /src/autohint/ahangles.c/
/***************************************************************************/
/* */
/* ahangles.h */
/* */
/* a routine used to compute vector angles with limited accuracy */
/* and very high speed. */
/* */
/* Copyright 2000: 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 */
/* */
/***************************************************************************/
#ifdef FT_FLAT_COMPILE
#include "ahangles.h"
#else
#include <autohint/ahangles.h>
#endif
/* the following two tables are automatically generated with */
/* the "mather.py" Python script.. */
static 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
};
LOCAL_FUNC
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;
}