x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
Pamdepth User Manual(0) Pamdepth User Manual(0)
NAME
pamdepth - change the depth (color resolution) in a Netpbm image
SYNOPSIS
pamdepth newmaxval [netpbmfile]
DESCRIPTION
This program is part of Netpbm(1).
pamdepth reads a Netpbm image as input, changes its depth (color reso-
lution), and writes out the resulting Netpbm image. I.e. the output
has a different maxval from the input, but all the same colors (apart
from rounding error).
Reducing the depth results in some loss of information.
Here is an example of the effect at the image format level: Assume you
start with an image with maxval 100 and sample values of 50 and 100.
You tell pamdepth to change it to depth 150. The output has maxval 200
and sample values 75 and 150.
This program works on multi-image streams.
Be careful of off-by-one errors when choosing the new maxval. For in-
stance, if you want the color values to be five bits wide, use a maxval
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
readable by any program that worked with PNM files before April 2000.
SEE ALSO
pnm(5), pam(5), pnmquant(1), ppmdither(1) ppmbrighten(1) pamfunc(1)
HISTORY
pamdepth was new in Netpbm 10.32 (February 2006). It replaced pn-
mdepth, by Jef Poskanzer. pamdepth is backward compatible with pn-
mdepth and 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 first in any stream.
DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML
source. The master documentation is at
http://netpbm.sourceforge.net/doc/pamdepth.html
netpbm documentation 19 December 2013 Pamdepth User Manual(0)
Want to link to this manual page? Use this URL:
<http://star2.abcm.com/cgi-bin/bsdi-man?query=pamdepth&sektion=1&manpath=>