(PHP 4)
swf_viewport — Select an area for future drawing
$xmin
   , float $xmax
   , float $ymin
   , float $ymax
   )
   Selects an area for future drawing for xmin to
   xmax and ymin to
   ymax, if this function is not called the
   area defaults to the size of the screen.
  
xmin
xmax
ymin
ymax
No value is returned.