Nested User Interface Components combine the concepts of Zooming User Interfaces (ZUIs) with recursive nesting of active graphical user interface widgets. The resulting system of recursively nesting interface components has a number of desirable properties. The level of detail of the view of any widget component and its children, as well as the responsiveness of that component to the user?s actions, can be tuned to the current visible size of that component on the screen.
We distinguish between the interaction style of a component, and the semantic result that it produces. Only the latter is used to determine the geographic parameters for that component. In this way, very large and layered control problems can be presented to the user as a cohesive and readily navigable visual surface. It becomes straightforward to layout interaction semantics that are best handled by recursion, such as filters composed of nested expressions.