pointing

We present the satellite cursor - a novel technique that uses multiple cursors to improve pointing performance by reducing input movement. The satellite cursor associates every target with a separate cursor in its vicinity for pointing, which realizes the MAGIC (manual and gaze input cascade) pointing method without gaze tracking. We discuss the problem of visual clutter caused by multiple cursors and propose several designs to mitigate it. Two controlled experiments were conducted to evaluate satellite cursor performance in a simple reciprocal pointing task and a complex task with multiple targets of varying layout densities. Results show the satellite cursor can save significant mouse movement and consequently pointing time, especially for sparse target layouts, and that satellite cursor performance can be accurately modeled by Fitts' Law.

Position control devices enable precise selection, but significant clutching degrades performance. Clutching can be reduced with high control-display gain or pointer acceleration, but there are human and device limits. Elastic rate control eliminates clutching completely, but can make precise selection difficult. We show that hybrid position-rate control can outperform position control by 20% when there is significant clutching, even when using pointer acceleration. Unlike previous work, our RubberEdge technique eliminates trajectory and velocity discontinuities. We derive predictive models for position control with clutching and hybrid control, and present a prototype RubberEdge position-rate control device including initial user feedback.

We present Abracadabra, a magnetically driven input technique that offers users wireless, unpowered, high fidelity finger input for mobile devices with very small screens. By extending the input area to many times the size of the device's screen, our approach is able to offer a high C-D gain, enabling fine motor control. Additionally, screen occlusion can be reduced by moving interaction off of the display and into unused space around the device. We discuss several example applications as a proof of concept. Finally, results from our user study indicate radial targets as small as 16 degrees can achieve greater than 92% selection accuracy, outperforming comparable radial, touch-based finger input.

Asynchronous collaborators often use freeform ink annotations to point to visually salient perceptual features of line charts such as peaks or humps, valleys, rising slopes and declining slopes. We present a set of techniques for interpreting such annotations to algorithmically identify the corresponding perceptual parts. Our approach is to first apply a parts-based segmentation algorithm that identifies the visually salient perceptual parts in the chart. Our system then analyzes the freeform annotations to infer the corresponding peaks, valleys or sloping segments. Once the system has identified the perceptual parts it can highlight them to draw further attention and reduce ambiguity of interpretation in asynchronous collaborative discussions.

This paper reports on the design and evaluation of UIMarks, a system that lets users specify on-screen targets and associated actions by means of a graphical marking language. UIMarks supplements traditional pointing by providing an alternative mode in which users can quickly activate these marks. Associated actions can range from basic pointing facilitation to complex sequences possibly involving user interaction: one can leave a mark on a palette to make it more reachable, but the mark can also be configured to wait for a click and then automatically move the pointer back to its original location, for example. The system has been implemented on two different platforms, Metisse and OS X. We compared it to traditional pointing on a set of elementary and composite tasks in an abstract setting. Although pure pointing was not improved, the programmable automation supported by the system proved very effective.

This paper introduces kinematic templates, an end-user tool for defining content-specific motor space manipulations in the context of editing 2D visual compositions. As an example, a user can choose the "sandpaper" template to define areas within a drawing where cursor movement should slow down. Our current implementation provides templates that amplify or dampen the cursor's speed, attenuate jitter in a user's movement, guide movement along paths, and add forces to the cursor. Multiple kinematic templates can be defined within a document, with overlapping templates resulting in a form of function composition. A template's strength can also be varied, enabling one to improve one's strokes without losing the human element. Since kinematic templates guide movements, rather than strictly prescribe them, they constitute a visual composition aid that lies between unaided freehand drawing and rigid drawing aids such as snapping guides, masks, and perfect geometric primitives.