Bimanual Interaction for Tablet Computing

Interfaces that receive the majority of input through an electronic stylus often overload the stylus via software state, creating a set of modes in the interface. Typical examples of these interfaces are found in applications designed primarily for a tablet computer or data tablet, such as Windows Journal and Microsoft OneNote. In these applications a set of software buttons at the top of the screen allows a user to change the state of the tablet interface to support actions such as inking, erasing, highlighting, and editing to create and manipulate content. Prior to my work, these state manipulation operations were shown to be error-prone and have a high temporal cost.

To address the temporal cost associated with switching software state, my collaborators and I developed an interaction technique for switching software states that is based on bimanual coordination. The technique, called concurrent bimanual mode switching, allows a user to overlap the selection of software state using their non-preferred hand while performing a gesture with the preferred hand. We demonstrated that this technique allows a user to spend less time switching software state while providing interface designers with the ability to provide more options (i.e. states) to the user than previous techniques.

Recently, I collaborated with Matei Negelescu (a master's student at University of Waterloo) to develop and evaluate a bimanual interaction technique to support mixed resolution sketching on multi-touch tablet devices, i.e. iPad and Android-based tablets. The technique, called ZoomSketch, is a bimanual interaction technique where zooming is performed by setting the target with the nondominant hand while the dominant hand establishes the direction and magnitude of the expansion. Initial evaluation comparing the technique to the traditional pinch-based interaction used on many current devices (e.g. the iPhone and iPad) demonstrated that ZoomSketch offers benefits in terms of performance and degree of control.

A model of non-preferred hand mode switching
Jaime Ruiz, Andrea Bunt, and Edward Lank. 2008. In Proceedings of Graphics Interface 2008 (GI '08). Canadian Information Processing Society, Toronto, Ont., Canada, Canada, 49-56.