126 lines
3.8 KiB
C
126 lines
3.8 KiB
C
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/***************************************************************************/
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/* */
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/* ahangles.h */
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/* */
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/* a routine used to compute vector angles with limited accuracy */
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/* and very high speed. */
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/* */
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/* Copyright 2000: Catharon Productions Inc. */
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/* Author: David Turner */
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/* */
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/* This file is part of the Catharon Typography Project and shall only */
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/* be used, modified, and distributed under the terms of the Catharon */
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/* Open Source License that should come with this file under the name */
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/* "CatharonLicense.txt". By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/* Note that this license is compatible with the FreeType license */
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/* */
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/***************************************************************************/
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#ifdef FT_FLAT_COMPILE
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#include "ahangles.h"
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#else
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#include <autohint/ahangles.h>
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#endif
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/* the following two tables are automatically generated with */
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/* the "mather.py" Python script.. */
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static const AH_Angle ah_arctan[ 1L << AH_ATAN_BITS ] =
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{
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0, 0, 1, 1, 1, 2, 2, 2,
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3, 3, 3, 3, 4, 4, 4, 5,
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5, 5, 6, 6, 6, 7, 7, 7,
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8, 8, 8, 9, 9, 9, 10, 10,
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10, 10, 11, 11, 11, 12, 12, 12,
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13, 13, 13, 14, 14, 14, 14, 15,
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15, 15, 16, 16, 16, 17, 17, 17,
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18, 18, 18, 18, 19, 19, 19, 20,
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20, 20, 21, 21, 21, 21, 22, 22,
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22, 23, 23, 23, 24, 24, 24, 24,
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25, 25, 25, 26, 26, 26, 26, 27,
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27, 27, 28, 28, 28, 28, 29, 29,
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29, 30, 30, 30, 30, 31, 31, 31,
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31, 32, 32, 32, 33, 33, 33, 33,
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34, 34, 34, 34, 35, 35, 35, 35,
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36, 36, 36, 36, 37, 37, 37, 38,
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38, 38, 38, 39, 39, 39, 39, 40,
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40, 40, 40, 41, 41, 41, 41, 42,
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42, 42, 42, 42, 43, 43, 43, 43,
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44, 44, 44, 44, 45, 45, 45, 45,
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46, 46, 46, 46, 46, 47, 47, 47,
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47, 48, 48, 48, 48, 48, 49, 49,
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49, 49, 50, 50, 50, 50, 50, 51,
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51, 51, 51, 51, 52, 52, 52, 52,
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52, 53, 53, 53, 53, 53, 54, 54,
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54, 54, 54, 55, 55, 55, 55, 55,
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56, 56, 56, 56, 56, 57, 57, 57,
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57, 57, 57, 58, 58, 58, 58, 58,
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59, 59, 59, 59, 59, 59, 60, 60,
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60, 60, 60, 61, 61, 61, 61, 61,
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61, 62, 62, 62, 62, 62, 62, 63,
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63, 63, 63, 63, 63, 64, 64, 64
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};
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LOCAL_FUNC
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AH_Angle ah_angle( FT_Vector* v )
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{
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FT_Pos dx, dy;
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AH_Angle angle;
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dx = v->x;
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dy = v->y;
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/* check trivial cases */
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if (dy == 0)
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{
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angle = 0;
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if (dx < 0)
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angle = AH_PI;
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return angle;
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}
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else if (dx == 0)
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{
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angle = AH_HALF_PI;
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if (dy < 0)
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angle = -AH_HALF_PI;
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return angle;
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}
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angle = 0;
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if ( dx < 0 )
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{
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dx = -v->x;
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dy = -v->y;
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angle = AH_PI;
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}
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if ( dy < 0 )
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{
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FT_Pos tmp;
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tmp = dx;
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dx = -dy;
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dy = tmp;
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angle -= AH_HALF_PI;
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}
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if (dx == 0 && dy == 0)
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return 0;
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if (dx == dy)
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angle += AH_PI/4;
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else if (dx > dy)
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angle += ah_arctan[ FT_DivFix( dy, dx ) >> (16-AH_ATAN_BITS) ];
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else
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angle += AH_HALF_PI - ah_arctan[ FT_DivFix( dx, dy ) >> (16-AH_ATAN_BITS) ];
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if (angle > AH_PI)
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angle -= AH_2PI;
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return angle;
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}
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