/**
* Draw an arc of radius r, centred on (x, y), from angle1 to angle2 (in degrees).
*
* @param x the x-coordinate of the centre of the circle
* @param y the y-coordinate of the centre of the circle
* @param r the radius of the circle
* @param angle1 the starting angle. 0 would mean an arc beginning at 3 o'clock.
* @param angle2 the angle at the end of the arc. For example, if you want a 90 degree arc, then
* angle2 should be angle1 + 90.
* @throws RuntimeException if the radius of the circle is negative
*/
public static void arc(double x, double y, double r, double angle1, double angle2) {
offscreen.draw(ShapeAssist.arc(x, y, r, angle1, angle2));
draw();
}
