programmers hierarchical interactive graphics system (PHIGS)

The programming of graphics systems should be device-independent so that the application software can be ported to other graphics systems. The Programmers Hierarchical Interactive Graphics System (PHIGS), standardized by the International Standards Organization ( ISO), supports device-independent application programming of graphics systems, as does the Graphics Core System( GKS).

PHIGS can be used to define nested hierarchical structures. PHIGS consists of two subsystems for data definition and data representation and manages a data store for the creation of graphic structures. Whereby a graphic structure includes different graphic elements like polygons, points, texts and graphic attributes like line type, color, line width etc. and can call other structures. This enables hierarchical structuring of data, inheritance of attributes and representation of instances. The structure concept simplifies programming and reduces the amount of data required for graphics.

PHIGS is designed for 3D graphics and offers various functions for illumination models and refined representations for curves and surfaces.