1al_calculate_arc(3)        Library Functions Manual        al_calculate_arc(3)
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NAME

6       al_calculate_arc
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SYNOPSIS

9              #include <allegro5/allegro_primitives.h>
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11              void al_calculate_arc(float* dest, int stride, float cx, float cy,
12                 float rx, float ry, float start_theta, float delta_theta, float thickness,
13                 int num_segments)
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DESCRIPTION

16       Calculates  an elliptical arc, and sets the vertices in the destination
17       buffer to the calculated positions.  If thickness <= 0, then num_points
18       of  points are required in the destination, otherwise twice as many are
19       needed.  The destination buffer should consist of regularly spaced  (by
20       distance  of stride bytes) doublets of floats, corresponding to x and y
21       coordinates of the vertices.
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23       Parameters:
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25       · dest - The destination buffer
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27       · stride - Distance (in bytes) between starts of  successive  pairs  of
28         coordinates
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30       · cx, cy - Center of the arc
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32       · rx, ry - Radii of the arc
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34       · start_theta - The initial angle from which the arc is calculated
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36       · delta_theta  -  Angular  span  of  the arc (pass a negative number to
37         switch direction)
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39       · thickness - Thickness of the arc
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41       · num_points - The number of points to calculate
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SEE ALSO

44       al_draw_arc(3), al_calculate_spline(3), al_calculate_ribbon(3)
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48Allegro reference manual                                   al_calculate_arc(3)