METHOD AND APPARATUS FOR REDUCING STORAGE REQUIREMENTS FOR DISPLAY DATA

摘要

A method and apparatus for reducing storage requirements for display data on a computer system. Data objects to be displayed are organized into display lists and each data object includes an object type, such as text, graphic, and image. The data objects are rasterized into an uncompressed band buffer and divided into non-intersecting bitmap regions each identified with one or more object types. Each non-empty region is assigned a compression algorithm dependent upon the type of the region and specified compression constraints. The regions are combined with each other into larger regions if appropriate, and each region is compressed using its assigned compression algorithm into a compressed band buffer, thus reducing the required storage space for the data objects. The compressed data is decompressed in scan line order with a selected decompression algorithm corresponding to the assigned compression algorithms to produce uncompressed output data. The uncompressed output data is supplied to an output display device for display.