Diagram Editing on Interactive Displays Using Multi-touch and Pen Gestures

Creating and editing graphs and node-link diagrams by means of digital tools are crucial activities in domains such as software or business process modeling. However, these tools have several drawbacks with regard to interaction techniques and usability. In order to address these issues, we investigate the promising combination of pen and multi-touch input on interactive displays. In this work, we contribute a gesture set to make the interaction with diagrams more efficient and effective by means of pen and hand gestures. Thereby, two prevalent mental models are supported: structural editing and sketching. The gesture set is based on the results of a previous pilot study asking users for suggestions to accomplish diagram editing tasks on tabletops. In this paper, we provide a careful analysis of the resulting userelicited gestures. We propose solutions to resolve ambiguities within this gesture collection and discuss design decisions for a comprehensible diagram editor. We also present the multi-touch and pen gesture set as a fully implemented prototype for diagram editing on interactive surfaces.