| 摘要 |
The present invention is directed to a general purpose raster image system. The present invention performs transformations on an original raster image, and optimizes the raster image decoding and display techniques, to dramatically increase the display performance capabilities by a factor of up to fifteen times the performance provided by previous raster devices. The present invention employs two primary enhanced display features to produce fast raster image decode and display results: (1) data reduction and transformations and (2) optimized algorithmic implementations. Data reduction and transformations operate as follows: a raster image is divided into strips, which are processed individually. A feature of the optimized algorithmic implementation is to increase processing thruput of the display process by optimizing the use of available resources required to decode and display the raster images. In one embodiment, scaling operations are converted from calculation based algorithms, to data lookup tables indexed by the position of the raster image data in the original scan line. Raster image decoding algorithms are changed from iterative conditional loops to redundant code segments individually tailored for specific occurrences of raster image data. Additionally implementation of assembly language in time critical sections of display procedures allocates CPU register resources more efficiently and significantly increases performance.
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