PPMARITH

NAME

      ppmarith - perform arithmetic on two portable pixmaps

SYNOPSIS

      ppmarith -add|-subtract|-multiply ppmfile1 ppmfile2

DESCRIPTION

      Reads two portable bitmaps as input.  Performs the specified
      arithmetic operation, and produces a portable bitmap as output.  The
      two input pixmaps must be the same width and height.
      The arithmetic is performed between corresponding pixels in the two
      bitmaps, with maxval as 1.0, black as 0.0, and a linear scale in
      between.  Results that fall outside of [0..1) are truncated.
      All flags can be abbreviated to their shortest unique prefix.

SEE ALSO

      pbmmask(1), pbmpaste(1), pnminvert(1), ppm(5)

AUTHOR

      Copyright (C) 1989 by Jef Poskanzer.
      Permission to use, copy, modify, and distribute this software and its
      documentation for any purpose and without fee is hereby granted,
      provided that the above copyright notice appear in all copies and that
      both that copyright notice and this permission notice appear in
      supporting documentation.  This software is provided "as is" without
      express or implied warranty.