Mantis: A Screen Magnification Tool for Diagram Traversal

Abstract

Complex diagrams and charts can be difficult for people who use screen magnification to navigate. A sense of spatial context and of the diagram’s overall structure is oftentimes lost, as magnifiers can only magnify a fraction of the screen at any given time. So, while sighted users have both clarity and full context simultaneously, screen magnifier users often have to choose or split their attention between the two. Existing screen magnifiers are content-agnostic, so the current way of navigating visualizations is freeform and unguided. The burden of figuring out where to explore while retaining a mental model of the diagram is placed entirely on the user. In this paper, we present Mantis—six prototypes of an automatic, content-aware screen magnification tool designed to aid people who have low vision in the traversal of diagrams. Each design experiments with what sorts of information might be provided to help the user retain a sense of context. Further, they each explore how such a tool might use its knowledge of the diagram’s semantic structure to streamline traversal to and from areas of interest to the user. To this end, we evaluate how these proof-of-concepts improve the user’s navigational experience and reduce the user’s cognitive load.