A Shareable Centralised Database of KRT3 - A Hierarchical Graphics System Based on PHIGS

Abstract

The Programmer’s Hierarchical Interactive Graphics System (PHIGS), currently under development by ISO, is a specification of a set of functions for device-independent computer graphics programming, supporting dynamic interaction and hierarchically organised graphical data. A central aspect of an implementation of a system such as PHIGS is the provision of a compact and efficient representation for the graphical entities involved. This paper describes a centralised graphical database for KRT³, an experimental hierarchical graphics system based on PHIGS. It presents a discussion of the issues involved, and the experience gained, in the practical design and implementation of a database for hierarchical graphical data. A novel aspect of the design is that the database may be simultaneously shared by several application programs.