pdf_setgray double values start at 0 for black and end at 1 for white so for any shade of gray simply pick a value inbetween these 2 numbers
(PHP 4, PECL pdflib >= 1.0.0)
PDF_setgray — Set color to gray [deprecated]
$p
, float $g
)
Sets the current fill and stroke color to a gray value between 0 and 1 inclusive. 成功时返回 TRUE， 或者在失败时返回 FALSE。
This function is deprecated since PDFlib version 4, use PDF_setcolor() instead.
pdf_setgray double values start at 0 for black and end at 1 for white so for any shade of gray simply pick a value inbetween these 2 numbers