3x magnification filter
'hq3x' is a fast, high-quality 3x magnification filter. It was designed for use images with clear sharp edges, like line graphics or cartoon sprites, and to be fast enough to process 256x256 images in real-time. It sorts each pixel as 'close' or distant' depending on it relationship with its neighbors. This is then filtered through a lookup table with 256 entries, one for each combination of close/distant colored neighbors. Each entry describes how to mix the colors of the source pixels from the 3x3 area to get interpolated pixels of the filtered image. For each combination a vector representation is created and rasterised with higher (3x) resolution using anti-aliasing, and the result is stored in a lookup table.
released on 25 July 2003
This entry (in part or in whole) was last reviewed on 29 January 2004.
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