(PECL ps >= 1.1.0)
ps_arcn — Draws an arc clockwise
$psdoc
   , float $x
   , float $y
   , float $radius
   , float $alpha
   , float $beta
   )
   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.
  
psdoc
     Resource identifier of the postscript file as returned by ps_new().
x
     The x-coordinate of the circle's middle point.
y
     The y-coordinate of the circle's middle point.
radius
     The radius of the circle
alpha
     The starting angle given in degrees.
beta
     The end angle given in degrees.
   Returns TRUE on success or FALSE on failure.