Display PostScript is an enhanced version of PostScript which includes facilities for the display on computer screens and also the ability to be used for interactive applications.
Just as PostScript allows output files to be described in a printer-independent manner, Display PostScript provides a similar function for displaying PostScript files on different display screens. While the standard PostScript language allows for just previewing documents on different display screens, Display PostScript is interactive, providing functions that include editing, clipping and the simultaneous display of separate documents.
Display PostScript includes many functions that allow it to be connected to windowing systems, but it is not in itself a windowing system. To create this, extra parts are added to the specific adaption of Display PostScript which works on any particular machine.