Abstract Interaction Objects

Abstract

The concept of an interactor has been introduced by Faconti and Paterno [6] as an abstraction of an entity in interactive graphics capable of both input and output. However the notion of interaction object need not be confined to graphics systems- it represents a useful structure for thinking and reasoning about the behaviour of interactive systems in general. As part of Esprit Basic Research Action 7040 (Amodeus-2) we are using the concept of interactor, and existing work on state-based processes and agents, to develop a model and theory of interactive systems. In this paper we describe two formal models for interaction objects and sketch how they can be used to build a small vocabulary of operators to support the rigorous specification of a graphics system. Our model differs from the approach of Faconti and Paterno in that it abstracts away from any specific graphics framework and is thus suited to the level of abstraction demanded by formal approaches to system development.