Abstract
Bare hand pointing on touch screens both benefits and suffers from the nature of direct input. This work explores techniques to overcome its limitations. Our goal is to design interaction tools allowing pixel level pointing in a fast and efficient manner. Based on several cycles of iterative design and testing, we propose two techniques: Cross-Keys that uses discrete taps on virtual keys integrated with a crosshair cursor, and an analog Precision-Handle that uses a leverage (gain) effect to amplify movement precision from the user's finger tip to the end cursor. We conducted a formal experiment with these two techniques, in addition to the previously known Zoom-Pointing and Take-Off as baseline anchors. Both subjective and performance measurements indicate that Precision-Handle and Cross-Keys complement existing techniques for touch screen interaction. Copyright 2003 ACM.