Planning-based control of interface animation

Animations express a sense of process and continuity that is difficult to convey through other techniques. Although interfaces can often benefit from animation, User Interface Management Systems (UIMSs) rarely provide the tools necessary to easily support complex, state-dependent application output, such as animations. Here we describe Player, an interface component that facilitates sequencing these animations. One difficulty of integrating animations into interactive systems is that animation scripts typically only work in very specific contexts. Care must be taken to establish the required context prior to executing an animation. Player employs a precondition and postcondition-based specification language, and automatically computes which animation scripts should be invoked to establish the necessary state. Player’s specification language has been designed to make it easy to express the desired behavior of animation controllers. Since planning can be a timeconsuming process inappropriate for interactive systems, Player precompiles the plan-based specification into a state machine that executes far more quickly. Serving as an animation controller, Player hides animation script dependencies from the application. Player has been incorporated into the Persona UIMS, and is currently used in the Peedy application.