A Distributable, Display-Device-Independent Vector Graphics System for Command and Control

This report documents a distributable, device-independent vector graphics system developed by ISI for the Defense Advanced Research Projects Agency. It describes the system architecture, communications elements, and a phased implementation strategy. The system supports graphics-based command and control applications in distributed computational environments such as the ARPANET. The system has been in use at ISI and at the Naval Ocean Systems Center (NOSC) in the Advanced Command and Control Architectural Testbed (ACCAT) since January 1977. The principal aim of the development effort is the device- independence of the vector graphics. 'Device-independence' means that graphic application programs can be written without regard to the particular display- device on which the output will ultimately be displayed. This system achieves display-device independence by providing the application program with a set of generic, two-dimensional vector graphic primitives by which pictures can be described and interacted with at the application-level. The particular graphics model used structures pictures as sets of subpictures that are absolute- transformed-segments, as defined by Newman and Sproull.