(PECL ps >= 1.1.0)
ps_scale — Sets scaling factor
$psdoc, float $x, float $y): boolSets horizontal and vertical scaling of the coordinate system.
psdocResource identifier of the postscript file as returned by ps_new().
xScaling factor in horizontal direction.
yScaling factor in vertical direction.
成功时返回 true， 或者在失败时返回 false。