(PECL ps >= 1.1.0)
ps_clip — Clips drawing to current path
$psdoc
Takes the current path and uses it to define the border of a clipping area. Everything drawn outside of that area will not be visible.
psdoc
Resource identifier of the postscript file as returned by ps_new().
成功时返回 true， 或者在失败时返回 false。
true
false