Sgitopnm User Manual(0)                                Sgitopnm User Manual(0)



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
       -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 alpha (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(5) , pam(5) , pnmtosgi(1) , pamstack(1)




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

netpbm documentation             25 April 2014         Sgitopnm User Manual(0)