(23) TRIP2a/3D : A 3D Declarative Algorithm Animation System

Animation is useful in user interfaces, especially for representing dynamic features. However, it is often difficult and laborious to create animation in an existing user interface environment. In this research, we extend our bi-directional translation model to deal with animations. The new model incorporates the notion of time, and includes operations defined for each representation in the model. Using this model, animation is basically achieved by interpolating successive visualized pictures of application data. Other than specifying the way of visualizing application data, programmers have only to provide mapping rules between abstract operations and interpolating methods, and as a result, complex animation effects can be easily specified. We have developed a system based on this model. This system consists of two parts: a mapper and a viewer. A mapper receives a series of data from an application, and translates them into pictures, which are interpolated and converted to an animation log. An animation log from a mapper can be viewed as an animation using a viewer. We provides three viewers for IRIX (OpenInventor), Windows95/NT (OpenGL), and X-Window system. We applied this system to several algorithm animations, such as N-Queen Problem, the tower of Hanoi, and N-Body simulation program.