Quartz's feature-rich drawing engine leverages the Portable Document Format (PDF) drawing model and offers MacOSX applications professional-strength drawing functionality.

Quartz is modeled after PDF, as Apple has said themselves - re:link above, as many other apple developer links point out.

Apple implemented the PDF format on their own, without assistance by Adobe. PDF does contain some elements of the Postscript language - read as: some, but PDF is a different document model.

Postcript is also a license-based technology, whereas PDF is an open standard. If you want "free" Postscript, you have to use Ghostscript.

-- Don't rant without proper information and experience.