Animation techniques for chain-coded objects

The animation of two-dimensional objects in a 2-D planar environment is discussed. The use of chain codes as a boundary representation for 2-D objects undergoing animation is shown to be practical for several typical transformations. Various methods for implementing the transformations are described. Quantized methods transform groups of chain code elements into other groups, while incremental methods construct the transformed chain code element by element. The low cost of quantized methods, which rely on table lookup and minimal arithmetic, are weighed against the increased accuracy offered by incremental methods, which maintain error indicators to ensure minimal differences between ideal and generated chain codes. Methods for scaling, rotation, and elastic deformation of objects based solely on chain code elements are discussed.