Pantone and HKS spot colors - it's not supported in free version PDFLib Lite
(PHP 4 >= 4.0.5, PECL pdflib >= 1.0.0)
PDF_makespotcolor — Make spot color
$p
, string $spotname
) : int
Finds a built-in spot color name, or makes a named spot color from the
current fill color. 成功时返回 TRUE， 或者在失败时返回 FALSE。
Pantone and HKS spot colors - it's not supported in free version PDFLib Lite