Techniques for Interacting with Off-Screen Content

Many systems - such as map viewers or visual editors - provide a limited viewport onto a larger graphical workspace. The limited viewport means that users often have to navigate to objects and locations that are off screen. Although techniques such as zooming, panning, or overview+detail views allow users to navigate off-screen, little is known about how different techniques perform for different types of off-screen tasks, and whether one technique works well for all tasks. We carried out two studies to explore these issues. The first study compared the performance of three classes of techniques (zoom, overview+detail, and proxy) in six types of off-screen tasks. We found that the techniques show substantial differences across different tasks and that no one technique is suitable for all types of off-screen navigation. This study led to the design of two novel hybrid navigation techniques - WinHop and Multiscale Zoom - that combine properties of multiple simpler approaches in an attempt to broaden support for off-screen navigation. We carried out a second study to assess the hybrid techniques, and found that they do provide reliable performance on a wide range of tasks. Our results suggest that integrating complimentary properties from different approaches can significantly improve performance in off-screen navigation tasks.