Display Ghostscript (DGS) is functionally upward-compatible with Adobe Display PostScript, but it has been written independently. The Display Ghostscript System provides a device-independent imaging model for displaying information on a screen. The imaging model uses the PostScript language which has powerful graphics capabilities and frees the programmer from display-specific details like screen resolution and color issues. DGS is an integral part of the GNUstep Development Environment.
Netclasses is an asynchronous networking library that works with GNUstep and Mac OS X. Out of the box, it gives a nice, asynchronous, and object-oriented interface for IRC, line- based, and raw TCP/IP connections. Users can easily subclass the raw TCP/IP or line-based interfaces to create asynchronous interfaces for other sorts of connections.