Dynamic space management for user interfaces

Abstract

We present a general approach to the dynamic representation of 2D space that is well suited for user-interface layout. We partition space into two distinct categories: full and empty. The user can explicitly specify a set of possibly overlapping upright rectangles that represent the objects of interest. These full-space rectangles are processed by the system to create a representation of the remaining empty space. This representation makes it easy for users to develop customized spatial allocation strategies that avoid overlapping the full-space rectangles. We describe the representation; provide efficient incremental algorithms for adding and deleting full-space rectangles, and for querying the empty-space representation; and show several allocation strategies that the representation makes possible. We present two testbed applications that incorporate an implementation of the algorithm; one shows the utility of our representation for window management tasks; the other applies it to the layout of components in a 3D user interface, based on the upright 2D bounding boxes of their projections.