[reissbaker]

Quartz was originally based on PDF and was marketed early on as "Display PDF" (a reference to being a more advanced version of "Display PostScript"): https://archive.arstechnica.com/reviews/1q00/macos-x-gui/mac...

[astrange]

Well, it wasn't really based on PDF to the point it stores PDFs in memory or anything. Like I said, it just has compatible drawing commands.

It's turned out that vector images aren't that performant or easy to deal with for various reasons, although they are still used in some places.