(PHP 4, PECL pdflib:1.0-2.1.3)
PDF_setgray_stroke — Set stroke color to gray [deprecated]
Sets the current stroke color to a gray value between 0 and 1 inclusive. 如果成功则返回 TRUE,失败则返回 FALSE。
This function is deprecated since PDFlib version 4, use PDF_setcolor() instead.