RLESETBG(1)                                         RLESETBG(1)





NAME
       rlesetbg - Set the background value in the RLE header.

SYNOPSIS
       rlesetbg  [ -{DO} ] [ -c bgcolor ...  ] [ -o outfile ] [
       infile ]

DESCRIPTION
       rlesetbg sets the background color field  in  the  image
       header of an RLE(5) image (none of the actual pixels are
       changed).  If infile isn't specified, the image is  read
       from stdin.

       The background color in the header is used to save space
       in the run-length encoded file.  Runs of background-col-
       ored  pixels  longer than 2 pixels are simply not saved.
       (Doing this for runs of 1 or  2  background  pixels  can
       make  the  saved  image  larger than if no encoding were
       done.)  Therefore, changing the  background  color  with
       rlesetbg may still leave some pixels saved in the origi-
       nal background color.  The -D  option  will  delete  the
       background color altogether from the header; this can be
       useful in certain circumstances, but can  also  lead  to
       very strange results.

OPTIONS
       -D     Delete any background specification that might be
              present.

       -O     Specifies that the image has  no  background,  it
              overlays existing images.

       -c bgcolor ...
              Specifies  the color values to set the background
              to.  There should be at least as many  values  as
              there are color channels in the image.  Use -- or
              another option to separate  the  list  of  colors
              from infile.

       -o outfile
              If  specified, the output will be written to this
              file.  If outfile is "-", or if it is not  speci-
              fied,  the output will be written to the standard
              output stream.

AUTHORS
       John W. Peterson and Rod Bogart

SEE ALSO
       repos(1), urt(1), RLE(5).

BUGS
       This should really be part of a single program that does
       all header munging...



1                      December 20, 1986            RLESETBG(1)
