/***************************************************************************/ | |

/* */ | |

/* 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 */ |