Improving selection of off-screen targets with hopping

Abstract

Many systems provide the user with a limited viewport of a larger graphical workspace. In these systems, the user often needs to find and select targets that are in the workspace, but not visible in the current view. Standard methods for navigating to the off-screen targets include scrolling, panning, and zooming; however, these are laborious when users cannot see a target's direction or distance. Techniques such as halos can provide awareness of targets, but actually getting to the target is still slow with standard navigation.To improve off-screen target selection, we developed a new technique called hop, which combines halos with a teleportation mechanism that shows proxies of distant objects. Hop provides both awareness of off-screen targets and fast navigation to the target context. A study showed that users are significantly faster at selecting off-screen targets with hopping than with two-level zooming or graband-drag panning, and it is clear that hop will be faster than either halos or proxy-based techniques (like drag-and-pop or vacuum filtering) by themselves. Hop both improves on halo-based navigation and extends the value of proxies to small-screen environments.

MIKAN GLOBE MT: An Interactive World Map featuring Seamless Map Projection and Guaranteed Visibility

“…City lights shining from the targets cast shadows on the edges of the display [17]. Other approaches replace off-screen targets with rectangles [18] or designate a substitute object for an off-screen target and pan the view automatically so that the target is displayed on the monitor [19]. Halos were selected for incorporation in this algorithm to help cognize targets between different windows when the user is using a divided screen.…”

Techniques for Interacting with Off-Screen Content

“…However, neither drag-and-pop nor the vacuum filter was designed as off-screen navigation techniques. Hop [13] is a proxy-based technique that was developed to adapt the proxy approach to the needs of off-screen navigation. Hop uses halos [1] to provide awareness of off-screen objects, and allows users to create proxies by interacting with the visible halos.…”

“…Zooming was chosen to represent the time-multiplexing class, since prior results show that zooming is superior to panning and scrolling for off-screen navigation [13]. We implemented a two-level zoom, where users move from overview to full detail by clicking the barrel button on the tablet pen.…”

“…Hopping was picked from the proxy class, since it is the only proxy-based technique that is designed for off-screen navigation [13]. Hop shows halos of off-screen objects; the user can invoke proxies by sweeping a 'laser beam' across the halos.…”

“…However, most studies have investigated the performance of these navigation techniques with only a limited range of tasks. For example, several studies have investigated scrolling, but primarily on tasks related to navigating to known off-screen content [7,10]; panning and zooming have been investigated primarily in the context of off-screen targeting and navigation [9,13], and focus+context techniques have been studied primarily with reading, targeting, and steering [3,8].…”