.TH "al_calculate_arc(3alleg5) Allegro reference manual" "" "" "" ""
.SH NAME
.PP
al_calculate_arc \- Allegro 5 API
.SH SYNOPSIS
.IP
.nf
\f[C]
#include\ <allegro5/allegro_primitives.h>

void\ al_calculate_arc(float*\ dest,\ int\ stride,\ float\ cx,\ float\ cy,
\ \ \ float\ rx,\ float\ ry,\ float\ start_theta,\ float\ delta_theta,\ float\ thickness,
\ \ \ int\ num_segments)
\f[]
.fi
.SH DESCRIPTION
.PP
Calculates an elliptical arc, and sets the vertices in the destination
buffer to the calculated positions.
If \f[C]thickness\ <=\ 0\f[], then \f[C]num_points\f[] of points are
required in the destination, otherwise twice as many are needed.
The destination buffer should consist of regularly spaced (by distance
of \f[C]stride\f[] bytes) doublets of floats, corresponding to x and y
coordinates of the vertices.
.PP
\f[I]Parameters:\f[]
.IP \[bu] 2
dest \- The destination buffer
.IP \[bu] 2
stride \- Distance (in bytes) between starts of successive pairs of
coordinates
.IP \[bu] 2
cx, cy \- Center of the arc
.IP \[bu] 2
rx, ry \- Radii of the arc
.IP \[bu] 2
start_theta \- The initial angle from which the arc is calculated
.IP \[bu] 2
delta_theta \- Angular span of the arc (pass a negative number to switch
direction)
.IP \[bu] 2
thickness \- Thickness of the arc
.IP \[bu] 2
num_points \- The number of points to calculate
.SH SEE ALSO
.PP
al_draw_arc(3alleg5), al_calculate_spline(3alleg5),
al_calculate_ribbon(3alleg5)