GCI: a Tool for Developing Interactive CAD User Interfaces

GCI is a Unix based tool for developing interactive CAD programs. By separating command/menu definitions from the program, GCI makes it easier to change and extend the user interface. The language provided by GCI is used to define syntax of commands, menus, messages, and help text. Generally, GCI supports a static hierarchical structure of commands and menus. However, through a program interface, an application program has the freedom to change environments, commands and menus. This flexibility of run-time control of the user interface is essential for developing highly responsive interfaces in a CAD environment. This paper presents the main concepts and definition language of GCI. It then discusses architectural and implementation issues, and finally presents a typical application's view of using the too