NAME

       sgitopnm - convert a SGI image file to PNM

SYNOPSIS

       sgitopnm

       [-verbose]

       [-channel c]

       [SgiFileName]

DESCRIPTION

       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.

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common  Options  ⟨index.html#commonoptions⟩  ), sgitopnm recognizes the following command
       line options:

       -verbose
              Give some information about the SGI image file.

       -channel n
              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.

REFERENCES

       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 .

SEE ALSO

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

AUTHOR

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

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/sgitopnm.html