Modeling pointing at targets of arbitrary shapes

Abstract

We investigate pointing at graphical targets of arbitrary shapes. We first describe a previously proposed probabilistic Fitts' law model [7] which, unlike previous models that only account for rectangular targets, has the potential to handle arbitrary shapes. Three methods of defining the centers of arbitrarily shaped targets for use within the model are developed. We compare these methods of defining target centers, and validate the model using a pointing experiment in which the targets take on various shapes. Results show that the model can accurately account for the varying target shapes. We discuss the implications of our results to interface design.