Tech Report CS-05-10

Fluid Inking: Modeless Integration of Gestures with Inking

Robert Zeleznik and Timothy Miller

July 2005


We present Fluid Inking, a novel approach for integrating gestural commands with freestyle inking that is also more generally applicable than previous techniques. Fluid Inking adapts the conventional GUI notions of tear-off menus and modifier-key shortcuts into the novel concepts of tear-off FluidButtons and gestural shortcuts, respectively. Fluid Inking is distinct among gesture-based interfaces because it fundamentally addresses four cornerstone gestural design criteria, including: 1) hardware generality: all gestures, including menu interactions, are available using only a button-free stylus, the least common denominator input device for systems ranging from PDAs to whiteboards; 2) performability: gestures are composed of very short sequences of simple and familiar inking interactions that require minimal targeting; 3) extensibility: gestures are conceived of as shortcuts for many of the commands in an arbitrarily scalable FlowMenu; and 4) discoverability: gesture shortcuts are displayed in the interactive FlowMenu and, in novice mode, they are suggested with dynamic feedback during inking. This paper presents the Fluid Inking design in the context of a broad prototype notetaking application with emphasis on how we use context, postfix terminal punctuation, and prefix Flicks to distinguish gestures from regular inking. We also discuss how the Fluid Inking design evolved based on user feedback.

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