Acquisition of expanding targets

Abstract

There exist several user interface widgets that dynamically grow in size in response to the user's focus of attention. Some of these, such as icons in toolbars, expand to facilitate their selection − allowing for a reduced initial size in an attempt to optimize screen space use. However, selection performance may be degraded by this decreased initial widget size. We describe an experiment which explores the effects of varying parameters of expansion techniques in a selection task. Our results suggest that Fitts' law can model and predict performance in such tasks. They also indicate that performance is governed by the target's final size, not its initial one. Further, performance is dependent on the target's final size even when the target only begins expanding as late as after 90% of the movement towards the target has already been completed. These results indicate that expanding widgets can be used without sacrificing performance.

The Impact of Control-Display Gain on User Performance in Pointing Tasks

“…PA is one of many techniques that influence the motor-space through which the device travels during target acquisition: High gain reduces the motor distance during ballistic movement, and low gain increases the motor size of the target during corrective action. Other successful examples of motor-space adaptation include McGuffin and Balakrishnan's (2002) expanding targets; Grossman and Balakrishnan's (2005) bubble cursor; and Blanch, Guiard, and Beaudouin-Lafon's (2004) semantic pointing, all of which dynamically adjust motorspace to reduce the target distance, increase the width, or both. These techniques, fully reviewed in Balakrishnan (2004), are all target oriented: The CD gain or the target/cursor area is dynamically adjusted as a result of the cursor's proximity to the target.…”

Adaptive Pointing – Design and Evaluation of a Precision Enhancing Technique for Absolute Pointing Devices

“…Unlike target-oriented approaches such as [11] and [12], Adaptive Pointing does not need any knowledge of the displayed information or active elements. However, it can be easily combined with visual interaction techniques such as expanding targets [19] or Dragand-Pop [20], as well as hand-tremor compensations (e.g. Kalman filter) if further pointing and selection improvement is desired.…”

Improving Target Acquisitions through Utilizing Pen Pressure

“…However, the effective width can be increased either for the cursor (Grossman & Balakrishnan, 2005;Kabbash & Buxton, 1995;Worden et al, 1997) or the target (Cockburn & Brock, 2006;McGuffin & Balakrishnan, 2002;Zhai et al, 2003) to achieve the same effect. Most previous studies have shown the effectiveness of their proposal only for single isolated target (McGuffin & Balakrishnan, 2002;Zhai et al, 2003), while they have not been shown to work well when multiple targets are present in close proximity (Cockburn & Brock, 2006;Guiard et al 2004;McGuffin & Balakrishnan, 2002;Zhai et al, 2003). The state of the art in this category is Bubble Cursor (Grossman & Balakrishnan, 2005), a mouse-based technique that allows selection of discrete targets by using a Voronoi diagram to associate void space with nearby targets.…”