pnmarith(1)

NAME

       pnmarith - perform arithmetic on two portable anymaps

SYNOPSIS

       pnmarith -add|-subtract|-multiply|-difference pnmfile1 pnmfile2

DESCRIPTION

       Reads two portable anymaps as input.  Performs the specified arithmetic
       operation, and produces a portable anymap as  output.   The  two  input
       anymaps must be the same width and height.

       The  arithmetic  is  performed  between corresponding pixels in the two
       anymaps, as if maxval was 1.0, black was 0.0, and  a  linear  scale  in
       between.  Results that fall outside of [0..1) are truncated.

       The  operator  -difference  calculates  the  absolute value of pnmarith
       -subtract pnmfile1 pnmfile2, i.e. no truncation is done.

       All flags can be abbreviated to their shortest unique prefix.

SEE ALSO

       pbmmask(1), pnmpaste(1), pnminvert(1), pnm(5)

AUTHOR

       Copyright (C) 1989, 1991 by Jef Poskanzer.  Lightly modified by  Marcel
       Wijkstra <wijkstra@fwi.uva.nl>

                                26 August 1993                     pnmarith(1)