Smooth animation of algorithms in a declarative framework

Supporting smooth image transitions is a valuable feature in software visualization systems, but it seems difficult to achieve in declarative frameworks, as they are basically data (and not event) driven. This paper discusses the problem of specifying an animated behavior of graphical objects in a declarative style, addressing both automation and customization possibilities. In particular in our framework graphical objects are able to automatically get animated when they appear onto a scene, when they change and, at last, when they disappear. Moreover animations can be customized by means of declarations encoded in a logic-based language. The framework offers basic libraries of default behaviors that the user can choose from, and methods for specifying new behaviors are also supported by the language.