A skeletal stroke is a kind of general brush stroke for changing the shape of pictures as if by bending, shearing, twisting, while conservating the aspect ratio of selected features on the picture. It is neither a simple warping nor texture mapping technique, but a new method for controlling the deformation of a picture. A deformation model of a coordinate system has been proposed taking into account cases of discontinuous or extreme bending. Complicated pictures can be built up hierarchically by defining higher order strokes and recursive strokes. It is therefore a powerful general drawing tool and extended image transformation instrument. The use of skeletal strokes as a replacement for affine transformations in IFS coding has been explored. A novel general anchoring mechanism is proposed, which allows arbitrary control of any point in the picture. This control flexibility is particularly desirable in computer animation and digital typography. As a result, virtual ‘2-D models...
S. C. Hsu, I. H. H. Lee, Neil E. Wiseman