The PECL/haru extension provides bindings for Haru Free PDF Library - free, cross platform, opensource software library for generating PDF files.
You can find the library here: » http://libharu.sourceforge.net.
This extension is EXPERIMENTAL. The behaviour of this extension—including the names of its functions and any other documentation surrounding this extension—may change without notice in a future release of PHP. This extension should be used at your own risk.