Quartz 2D is the primary graphics library in Mac OS X, it supersedes QuickDraw which was used in earlier versions of the Mac OS, now known as "Classic". Quartz 2D is based on version 1.4 of the Adobe Portable Document Format (PDF — a universal file format that preserves all of the fonts, formatting, colors and graphics of any source document, regardless of the platform used to create it.) It is descended from NeXT's Display PostScript.