Pressure-sensitive Pen Interactions

Pen-based computers bring the promise of tapping into people’s expressiveness with pen and paper and producing a platform that feels familiar while providing new functionalities only possible within an electronic medium. To this day, pen computers’ success is marginal because their interfaces mainly replicate keyboard and mouse ones. Maximizing the potential of pen computers requires redesigning their interfaces so that they are sensitive to the pen’s input modalities and expressiveness. In particular, pressure is an important and expressive, yet underutilized, pen input modality. This dissertation advances our knowledge about pressure-aware, pen-based interactions and how people use these techniques. We systematically explore their design by first investigating how pressure can affect pen interactions. We propose novel techniques that take advantage of the pressure modality of a pen to control, link, and annotate digital video. We then study people’s performance using pressure to navigate through a set of elements and find that they can discriminate a minimum of six different pressure regions. We introduce the concept of Pressure Widgets and suggest visual and interaction properties for their design. We later explore pressure’s use to enhance the adjustment of continuous parameters and propose Zliding, a technique in which users vary pressure to adjust the scale of the parameter space, while sliding their pen to perform parameter manipulations. We study Zliding and find it a viable technique, which is capable of enabling arbitrarily precise parameter adjustments. We finally present a novel interaction technique defined by the concurrent variation in pressure applied while dragging a pen. We study these pressure marks and find that they are a compact, orientation-independent, full interaction phrase that can be 30% faster than a stateof-the-art selection-action interaction phrase. This dissertation also makes a number of key contributions throughout the design and study of novel interaction techniques: -It identifies important design issues for the development of pressure-sensitive, pen operated widgets and interactions, -It provides design guidelines for interaction techniques and interface elements utilizing pressure-enabled input devices, -It presents empirical data on people’s ability to control pressure, and -It charts a visual design space of pressure-sensitive, pen-based interactions.Ph