GX appears to have started in a roundabout fashion, originally as an outline font system that would be added to the Mac OS. Included in the font rendering engine were a number of generally useful extensions, notably a fixed point coordinate system and a variety of curve drawing commands. The system also included a system for "wrapping" existing PostScript Type 1 fonts into its own internal format, which added bitmap preview versions for quick on-screen rendering. This project later took on an expanded role when Apple and Microsoft agreed to work together to form an alternative to PostScript fonts, which were extremely expensive, creating the TrueType effort based on Apple's existing efforts.