A formal specification of appearance and behaviour of visual environments

The problem of a formal specification of visual languages has been addressed in several works. Most of these approaches only describe the correct placement of graphic objects on a screen. Icons are not, however, static elements. They behave dynamically in order to interact with the user, other icons and application processes. In order to make a complete specification of icons, it is important to have a formal approach which can describe the graphical status and the reactive behaviour depending on the generated events. A combination of process and data algebra for this purpose is proposed. This approach was applied to describe a visual environment developed by a set of common interaction techniques.