GREG is a graphic utility package whose goal is to help people prepare plots of their data or of the results of theoretical computations. Major goals were device independence as much as possible AND efficient interactive use. It was kept in mind that drawings are usually prepared interactively and then the final result is sent to a good quality printer or saved for later use. Quick look on data is also often wanted. Hence, the design goals were both a simple, fast utility for simple things and a powerful, flexible system producing high quality plots. In addition, it was soon realised that a stand-alone utility was unadapted for complex, repetitive integrated plots as often required in theoretical modelling. Accordingly, the library version became part of the design goals.
With the advent of the X-Window system, GREG has been totally rewritten to take advantage of the multi-window and color facilities of X-Window. This new version also handles bitmap display of images, contour filling, etc..., with hardcopy facilities on PostScript devices.