<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML><HEAD><TITLE>Sgitopnm User Manual</TITLE></HEAD>
<BODY>
<H1>sgitopnm</H1>
Updated: 25 April 2014
<BR>
<A HREF="#index">Table Of Contents</A>
<H2>NAME</H2>
sgitopnm - convert a SGI image file to PNM
<H2 id="synopsis">SYNOPSIS</H2>
<B>sgitopnm</B>
[<B>-verbose</B>]
[<B>-channel</B> <I>c</I>]
[<I>SgiFileName</I>]
<H2 id="description">DESCRIPTION</H2>
<p>This program is part of <a href="index.html">Netpbm</a>.
<p><b>sgitopnm</b> reads an SGI image file as input and produces a PGM
image for a 2-dimensional (1- or 2-channel) input file, and a PPM image for
a 3-dimensional (3 or more channels) input file.
<P>Alternatively, the program produces a PGM image of any one of the
channels in the input file.
<p>Before Netpbm 10.67 (June 2014), <b>sgitopnm</b> does not work on 2-channel
SGI images. It fails if you try.
<p>If you don't specify the <i>SgiFileName</i> argument, input is from
Standard Input.
<p>Before Netpbm 10.67 (June 2014), <b>sgitopnm</b> requires its input to
be a seekable file, so for example you can't feed it from a pipe.
<H2 id="options">OPTIONS</H2>
<DL COMPACT>
<DT><B>-verbose</B>
<DD>Give some information about the SGI image file.
<DT><B>-channel</B> <I>n</I>
<DD>Extract channel <I>n</I> of the image as a PGM image.
<p>Without this option, <B>sgitopnm</B> extracts the first 3 channels as a PPM
image or, if the input has 1 or 2 channels, extracts the first channel as a
PGM image.
<p>A 2-channel image is grayscale plus transparency, so you can get
the transparency information with <b>-channel=2</b>. You could then
combine them into a PAM image of tuple type GRAYSCALE_ALPHA with
<b>pamstack</b>.
</DL>
<H2 id="references">REFERENCES</H2>
<p>The SGI image format specification version 1.0 is at
ftp://ftp.sgi.com/graphics/grafica/sgiimage.html .
<p>There is an example SGI file at
https://github.com/ZaaLabs/ZaaIL-TestImages/tree/master/SGI .
<H2 id="seealso">SEE ALSO</H2>
<B><A HREF="pnm.html">pnm</A></B>,
<B><A HREF="pam.html">pam</A></B>,
<B><A HREF="pnmtosgi.html">pnmtosgi</A></B>,
<B><A HREF="pamstack.html">pamstack</A></B>
<H2 id="author">AUTHOR</H2>
<p>Copyright (C) 1994 by Ingo Wilken
(<A HREF="mailto:Ingo.Wilken@informatik.uni-oldenburg.de">
Ingo.Wilken@informatik.uni-oldenburg.de</A>)
<HR>
<H2 id="index">Table Of Contents</H2>
<UL>
<LI><A HREF="#synopsis">SYNOPSIS</A>
<LI><A HREF="#description">DESCRIPTION</A>
<LI><A HREF="#options">OPTIONS</A>
<LI><A HREF="#references">REFERENCES</A>
<LI><A HREF="#seealso">SEE ALSO</A>
<LI><A HREF="#author">AUTHOR</A>
</UL>
</BODY>
</HTML>