ˆú " ®'¬ " X‚鉞‚ ¶‚½ž© " ®ƒy@bullet[ƒ~ƒ " Ƒo‚é‚ae‚éoeø—¦ " I Ƒiƒrƒq@bullet[ƒvƒ ‡ƒ " Speed-dependent Automatic Zooming for Efficient Document Navigation

We propose a navigation technique for browsing large documents that integrates rate-based scrolling with automatic zooming. The view automatically zooms out when the user scrolls rapidly so that the perceptual scrolling speed in screen space remains constant. As a result, the user can efficiently and smoothly navigate through a large document without becoming disoriented by extremely fast visual flow. By incorporating semantic zooming techniques, the user can smoothly access a global overview of the document during rate-based scrolling. We implemented several prototype systems, including a web browser, map viewer, image browser, and dictionary viewer. An informal usability study suggests that automatic zooming can be a helpful alternative to traditional scrolling when the zoomed out view provides appropriate visual cues.