Method and apparatus for pixel clipping source and destination windows in a graphics system

DETAILED DESCRIPTION Methods and apparatus for pixel clipping source and destination windows in graphics frame buffer systems solve the aforementioned needs in the art.
Methods and apparatus provided in accordance with the present invention allow window clipping to be performed in hardware rather than software, thereby greatly reducing processor time to accomplish the source and destination pixel block moves on a frame buffer and increasing the overall efficiency of the graphics frame buffer system.
Methods of moving blocks of pixel data within a frame buffer in a computer graphics frame buffer system comprise the steps of reading a source area from a frame buffer into a memory according to a plurality of source tiles, combining the source tiles with destination tiles in the memory, comparing pixel data identities in the frame buffer with pixel data identities in the memory to determine whether the pixel data identities in the frame buffer match the pixel data identities in the memory, discarding the pixels whose identities in the frame buffer do not match identities in the memory, and updating the frame buffer with the pixel data whose identities in the frame buffer match the pixel identities in the memory.
Systems provided in accordance with the present invention also solve the aforementioned long-felt needs.
Systems for moving data blocks from a source window to a destination window in a graphics system comprise memory means for storing source window data and destination window data, source window register means interfaced with the memory means for storing pixel value data and data concerning a pixel's location within the source window, first comparator means interfaced with the source window register means for comparing the pixel value data with a source window identifier, destination window register means interfaced with the memory means for storing the pixel value data within the destination window, second comparator means interfaced with the destination window register means for comparing the pixel value data with a destination window identifier, and combining means interfaced with the first and second comparator means for determining whether source pixels can be moved to the destination window