This part of ISO/IEC 9592 specifies a set of functions for computer graphics programming, the Programmers Hierarchical Interactive Graphics System (PHIGS). PRIGS is a graphics system for application programs that produce computer generated pictures on line graphics or raster graphics output devices. It supports operator input and interactions by supplying basic functions for graphical input and hierarchical picture definition. Picture definitions are retained in a centralized structure store where they may be edited by an application.

Pictures are displayed on workstations consisting of a single output device and a number of input devices. Several workstations can be used simultaneously. The application program is allowed to adapt its behaviour at a workstation to make best use of workstation capabilities.

Functions are specified for archiving picture definitions to file. In addition an interface to the Computer Graphics Metafile (ISO 8632) is described.
NOTE - For certain parameters of the functions, PHIGS defines value ranges as being reserved for registration (see 4.1.2). The meanings of these values will be defined using the established procedures.

This part of ISO/IEC 9592 defines a language independent nucleus of a graphics system for integration into a programming language. PHIGS is embedded in a language layer obeying the particular conventions of the language. Such language bindings are specified for ISO or ISO/IEC languages in ISO/IEC 9593.