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avg4 - Downfilter an image by simple averaging.
avg4 [ -o outfile
] [ infile ]
Avg4 downfilters an RLE image into a resulting
image of 1/4th the size, by simply averaging four pixel values in the input
image to produce a single pixel in the output. If the original image does
not contain an alpha channel, avg4 creates one by counting the number of
non-zero pixels in each group of four input pixels and using the count to
produce a coverage value. While the alpha channel produced this way is
crude (only four levels of coverage) it is enough to make a noticeable
improvement in the edges of composited images.
- infile
- The input
will be read from this file, otherwise, input will be taken from stdin.
- -o outfile
- If specified, output will be written to this file, otherwise
it will go to stdout.
fant(1)
, rlecomp(1)
, smush(1)
, urt(1)
, RLE(5)
.
Rod Bogart, John W. Peterson
Very simple minded - more elaborate
filters could be implemented.
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