Hierarchical Specification of Graphical User Interfaces using a Graph Grammar Approach

In this contribution we consider a rule based visual language for the specification of graphical user interfaces (GUIs). Our approach uses a graph rewrite approach in such a way that the state of a GUI is represented as a complex graph. The results of an action is represented by a rewrite rule on such graphs. Since the GUI features are represented as little pictures like windows, listboxes etc. it is necessary to define these problem oriented representations by a more abstract mathematical formalism. We use mathematical graphs to represent the semantics of the problem oriented representation. Complex actions and events are modeled by rewrite steps on these mathematical graphs. Usually complex GUIs are described by a hierarchy of interaction objects. Such a hierarchy is adequately expressed as a hierarchy of graph layers. We present how the various descriptions of picture graphs and mathematical graphs as well as visual rules and mathematical graph rewrite rules, respectively, are integrated by a method using special mappings.