pnmdepth

   Updated: 08 April 2000
   Table Of Contents

NAME

   pnmdepth - change the maxval in a PNM image

SYNOPSIS

   pnmdepth newmaxval [pnmfile]

DESCRIPTION

   This program is part of Netpbm.

   pnmdepth reads a PNM image as input, scales all the pixel val-
ues, and writes
   out the image with the new maxval. Scaling the colors down  to
a smaller
   maxval will result in some loss of information.

   Be  careful of off-by-one errors when choosing the new maxval.
For instance,
   if you want the color values to be five bits wide, use a  max-
val of 31, not
   32.

   One	important  use	of  pnmdepth  is  to convert a new format
2-byte-per-sample
   PNM	file  to  the	older  1-byte-per-sample  format.  Before
April 2000,
   essentially	all  raw  (binary)  format PNM files had a maxval
less than 256 and
   one byte per sample, and many programs may rely  on	that.  If
you specify a
   newmaxval   less  than 256, the resulting file should be read-
able by any
   program that worked with PNM files before April 2000.

SEE ALSO

   pnm, pnmquant, ppmdither

AUTHOR

   Copyright (C) 1989, 1991 by Jef Poskanzer.
     _________________________________________________________________



Table Of Contents

     * NAME
     * SYNOPSIS
     * DESCRIPTION
     * SEE ALSO
     * AUTHOR

UNIX/Linux commands referenced on this page:

1. as
2. convert
3. raw
4. less
5. file
6. pnmquant