Shift: a technique for operating pen-based interfaces using touch

Retrieving the stylus of a pen-based device takes time and requires a second hand. Especially for short intermittent interactions many users therefore choose to use their bare fingers. Although convenient, this increases targeting times and error rates. We argue that the main reasons are the occlusion of the target by the user's finger and ambiguity about which part of the finger defines the selection point. We propose a pointing technique we call Shift that is designed to address these issues. When the user touches the screen, Shift creates a callout showing a copy of the occluded screen area and places it in a non-occluded location. The callout also shows a pointer representing the selection point of the finger. Using this visual feedback, users guide the pointer into the target by moving their finger on the screen surface and commit the target acquisition by lifting the finger. Unlike existing techniques, Shift is only invoked when necessary--over large targets no callout is c...

• Type: Conference
• Year: 2007
• Where: CHI
• Authors: Daniel Vogel, Patrick Baudisch
• Keywords: CHI 2007, Human Computer Interaction, Precise Target Acquisition, Unaided Touch Screen, Unaltered Touch Screen