sgitopnm - convert a SGI image file to PNM

       Copyright (C) 1994 by Ingo Wilken ( Ingo.Wilken@informatik.uni-oldenburg.de)

       This program is part of Netpbm(1).

       sgitopnm  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.

       Alternatively, the program produces a PGM image of any one of the channels in the input file.

       Before Netpbm 10.67 (June 2014), sgitopnm does not work on 2-channel SGI images.  It fails if you try.

       If you don't specify the SgiFileName argument, input is from Standard Input.

       Before Netpbm 10.67 (June 2014), sgitopnm requires its input to be a seekable file, so  for  example  you
       can't feed it from a pipe.

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master  documentation
       is at

              http://netpbm.sourceforge.net/doc/sgitopnm.html

netpbm documentation                              25 April 2014                          SgitopnmUserManual(1)

       sgitopnm - convert a SGI image file to PNM

       In  addition  to  the options common to all programs based on libnetpbm (most notably -quiet, see  Common
       Options ), sgitopnm recognizes the following command line options:

       -verbose
              Give some information about the SGI image file.

       -channeln
              Extract channel n of the image as a PGM image.

              Without this option, sgitopnm 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.

              A 2-channel image is grayscale plus transparency, so you can get the transparency information with
              -channel=2.   You  could  then  combine  them  into a PAM image of tuple type GRAYSCALE_ALPHA with
              pamstack.

       The SGI image format specification version 1.0 is at ftp://ftp.sgi.com/graphics/grafica/sgiimage.html .

       There is an example SGI file at https://github.com/ZaaLabs/ZaaIL-TestImages/tree/master/SGI .

pnm(1), pam(1), pnmtosgi(1), pamstack(1)

sgitopnm

       [-verbose]

       [-channelc]

       [SgiFileName]