We discuss the design and implementation of VISAGE, an object-oriented user interface framework that is part of GE's FACE Flexible Architecture Compiler Environment [1]. High-level services include a domain-independent graph editor that provides standard methods for viewing and editing hierarchical graphs, including graph layout. Editors that are customized to a specific application are built by inheritance of the domain-independent graph editor's functionality and overloading of the display, selection and editing methods. At a lower layer, presentation objects are responsible for parsing user input, displaying application output, providing mouse sensitivity and command dialogue execution. These presentation objects separate the application from its user interface, and thus promote system modularity.

Many aspects of design automation software have similar requirements for representing, manipulating, and storing design information. The recognition of these common requirements in CAD tools, allows the Flexible Architecture Compilation Environment's (FACE) Core Environment to provide a suite of high level tools for the CAD developer. The Core Environment software has been developed using object-oriented software technology, and may be readily adapted to specific applications. The focus of the core environment is to improve the productivity of CAD tool developers through better tool integration and a state-of-the-art software development environment. This Core Environment software has been used in the development of an integrated tool set covering algorithm specification, structural synthesis, and physical assembly of digital hardware systems. The focus of this paper is on the Core Environment's organization and its use in application tool development.