(PECL ps >= 1.1.0)
ps_add_launchlink — Adds link which launches file
$psdoc,$llx,$lly,$urx,$ury,$filenamePlaces a hyperlink at the given position pointing to a file program which is being started when clicked on. The hyperlink's source position is a rectangle with its lower left corner at (llx, lly) and its upper right corner at (urx, ury). The rectangle has by default a thin blue border.
此说明在文档被打印或显示时不可见，只在文档用 Acrobat Distiller 或 Ghostview 转换成 PDF 时显示。
psdocResource identifier of the postscript file as returned by ps_new().
llxThe x-coordinate of the lower left corner.
llyThe y-coordinate of the lower left corner.
urxThe x-coordinate of the upper right corner.
uryThe y-coordinate of the upper right corner.
filenameThe path of the program to be started, when the link is clicked on.