A visual programming model for user interface animation

Animation is a natural way to represent dynamic behaviour, but the lack of models and the difficulty of programming animation have limited its introduction into the user interface (UI). Visual programming techniques may greatly simplify animation creation, but most of the current approaches are limited to a specific application class. The paper describes HandMove, a general and powerful model for UI animation, which allows visual programming. HandMove is able to express and to homogeneously combine various UI animation types: spontaneous, interactive and application-controlled animation. Its visual model extends path-based specification to describe continuous and sudden changes, dynamic trajectory modification, communication between objects, etc. The article also proposes a formal definition of the HandMove model as a visual programming language.