| 摘要 |
A source image is scaled to a destination image using a method which determines a first destination pixel position corresponding to a given source image pixel. The method comprises the steps of: compiling a scale table having one entry per source pixel in a "pixel group", the end destination pixel of a pixel group positioned where a first accumulation (i.e., "Scale Source Sum") of sets of m pixels, equals a second accumulation (i.e., "Scale Destination Sum") of sets n pixels, the Scale Source Sum derived by successively adding an m pixel set value for each successively read source pixel, and the Scale Destination Sum derived by successively adding an n pixel set value for each written destination pixel; factoring both an n source pixel set value and an m destination pixel set value by y, where y is a largest common denominator of both n and m, to derive "n (factored source)" and "m (factored destination)"; using the n(factored source) to determine an integer number of pixel groups between the first source image pixel and the initial source pixel, and determining a total number of destination pixels encompassed by the integer number of pixel groups; determining a position of the given source image pixel within a pixel group on the source raster image scan line; using the scale table to determine a corresponding destination pixel within the pixel group; finding the first destination pixel and positioning the scaled version of the source image thereat.
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