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Name

avg4 - Downfilter an image by simple averaging.

Synopsis

avg4 [ -o outfile ] [ infile ]

Description

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.

Options

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.

See Also

fant(1) , rlecomp(1) , smush(1) , urt(1) , RLE(5) .

Author

Rod Bogart, John W. Peterson

Bugs

Very simple minded - more elaborate filters could be implemented.


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