(PECL ps >= 1.1.0)
ps_arcn — Draws an arc clockwise
Draws a portion of a circle with at middle point at (x, y). The arc starts at an angle of alpha and ends at an angle of beta. It is drawn clockwise (use ps_arc() to draw counterclockwise). The subpath added to the current path starts on the arc at angle beta and ends on the arc at angle alpha.
Resource identifier of the postscript file as returned by ps_new().
The x-coordinate of the circle's middle point.
The y-coordinate of the circle's middle point.
The radius of the circle
The starting angle given in degrees.
The end angle given in degrees.
成功时返回 true， 或者在失败时返回 false。