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netpbm_10.0-15_amd64 **NAME**

pnmarith - perform arithmetic on two portable anymaps

**SYNOPSIS**

**pnmarith** **-add**|**-subtract**|**-multiply**|**-difference**|**-minimum**|**-maximum.** __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)