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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