PaperFold: Evaluating Shape Changes for Viewport Transformations in Foldable Thin-Film Display Devices

In this paper, we investigate the use of shape changes in a multi-segmented mobile device for triggering viewport transformations in its graphical interface. We study PaperFold, a foldable device with reconfigurable thin-film electrophoretic display tiles. PaperFold enables users to attach, reorient and fold displays in a mobile form factor that is thin and lightweight even when fully collapsed. We discuss how our design was informed by a participatory study that resulted in 14 preferred shape changes. In a subsequent study, we asked users to rank the utility of shape changes for triggering common view operations in map and text editing applications. Results suggest participants were able to attribute specific view operations as automated responses to folding, attaching, reorienting or detaching displays. Collated or full screen views were preferred when users collocated two displays. When adding a third display, alternative views such as toolbars or a list of apps were suggested. Showing 3D views was strongly associated with folding PaperFold segments into a three dimensional structure.