pamdepth
Updated: 08 April 2000
Table Of Contents
NAMEpamdepth ‐ change the maxval in a Netpbm image
SYNOPSISpamdepth newmaxval [netpbmfile]
DESCRIPTION
This program is part of Netpbm.
pamdepth reads a Netpbm image as input, scales all the pixel
values, and
writes out the image with the new maxval. Scaling the colors
down to a
smaller maxval will result in some loss of information.
This program works on multi‐image streams.
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 pamdepth 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, pam, pnmquant, ppmdither ppmbrighten pamfunc
HISTORYpamdepth was new in Netpbm 10.32 (February 2006). It replaced
pnmdepth, by
Jef Poskanzer. pamdepth is backward compatible with pamdepthand adds the
ability to process arbitrary PAM images and the ability to
process
multi‐image input streams. pnmdepth handled only PNM images
and ignored all
but the the first in any stream.
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Table Of Contents
* SYNOPSIS
* DESCRIPTION
* SEE ALSO
* HISTORY
