DragonFly On-Line Manual Pages

AVG4(1)                DragonFly General Commands Manual               AVG4(1)

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.

4th Berkeley Distribution      November 12, 1986                       AVG4(1)