Pacers: time-elastic objects

Current time-based presentation systems are rigid in that they assumethe running time of all components of a presentation is constant. Furthermore, most systems offer little or no supportfordynamically adapting the presentation quality to the (lack of) available system resources. In this paper, we introduce an object called a Pacer that is “timeelastic” in that it can adjust the quality of its presentation according to the amount of time available. We have implemented a direct manipulation graphical interface using pacersthat can automatically degradepresentation quality in a controlled fashion depending on the user’s input rate and the speed of the rendering system.