Patent ID: 6795589
Filing Date: 2004-09-21
Classification: G06T

Abstract:
A method of creating an image, said image being formed by rendering a plurality of graphical objects according to a hierarchical structure representing a compositing expression, the hierarchical structure including a plurality of nodes each representing a sub-expression of the compositing expression, each said object having a predetermined outline, said method comprising the steps of:dividing a space in which the outlines are defined into a plurality of mutually exclusive regions, each of the mutually exclusive regions being defined by a region outline substantially following at least one of the predetermined outlines or parts thereof, wherein each of the mutually exclusive regions has a corresponding one of the sub-expressions; optimizing each of the sub-expressions corresponding to each of the mutually exclusive regions by: examining said mutually exclusive region to determine those said objects which contribute to the mutually exclusive region; and modifying the sub-expression corresponding to that mutually exclusive region on the basis of the contribution of each of said objects within that mutually exclusive region, such that the hierarchical structure remains unchanged; and compositing the image according to the unchanged hierarchical structure using each of the optimized sub-expressions to create the image.