Out of the Window: A Multi-Medium

Abstract

This paper informally describes a presentation model for multiple media. In contrast to the display platform provided by standard window managers, this model supports richly structured media of high granularity with a wide range of visualisations and with few geometric restrictions. The full formal model (Took 1991c) also integrates graphical and textual media by allowing their arbitrary nesting without imposing a priority between them. In the implemented system Presenter, described here, the model is an objective structure which can be constructed dynamically and incrementally, and so can act as an interactive communication intermediary between users and applications. Such a presentation module is called a surface. A major benefit is that the user can directly manipulate surface objects independently of the application which created them. Such surface interaction factors a large proportion of the task of writing highly interactive applications. The UMA architecture (Took 1991b) describes how this can be achieved without sacrificing semantic feedback from the application to the surface.