ExTwAnPaSy: an Extensible Two-dimensional Animation/Paint System

This paper is about ExTwAnPaSy, an Extensible Two-dimensional Animation/Paint System. ExTwAnPaSy is designed as a testbed for integrating various animation and painting techniques. Utilizing a uniform internal representation (and accompanying operations on it) for all geometric primitives, ExTwAnPaSy can integrate direct manipulation-, key-framing based-, as well as procedurally defined animation techniques. A key item of the system is that it can be expanded in a modular way using the standard programming environment feature of dynamic linking. By making the uniform internal representation accessible externally (by means of an abstract data type), a close interaction between the basic system and the added functionalities is guaranteed