(PECL ps >= 1.1.0)
ps_setdash — Sets appearance of a dashed line
Sets the length of the black and white portions of a dashed line.
psdoc
Resource identifier of the postscript file as returned by ps_new().
on
The length of the dash.
off
The length of the gap between dashes.
成功时返回 true
, 或者在失败时返回 false
。