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From: hull@emily.uvm.edu (Christopher Hull)
Newsgroups: comp.sys.sgi
Subject: colormaps in .im8 rasterfiles
Message-ID: <1236@uvm-gen.UUCP>
Date: 21 Jul 89 20:29:58 GMT
Sender: nobody@uvm-gen.UUCP
Distribution: comp
Organization: EMBA-CF, University of Vermont
Lines: 20


	I have been trying to display some rasterfiles(.im8) images 
from my own program.  The files in particular are the ones the NeWS
imagedemo program uses (/usr/NeWS/smi) on the personal irises.  The
problem I am having is interpreting the colormap in the file.  My 
program displays the image and it is recognizable however the colors 
are definitely incorrect.  
	Right now I am using each byte in the image as an direct 
offset into each of the red, green, and blue colormaps, and plotting
a pixel with those components.  I have tried reversing and/or invert-
ing the colormaps with out any success.  Does anyone know how to 
correctly interpret the colormaps, or know how the NeWS operator
`imagecanvas' interprets the rasterfiles?  Any help or pointers would
be greatly appreciated.

Thanx,
Christopher Hull
EMBA-CF  University of Vermont,  Burlington, VT
--------------------
hull@uvm-gen.uvm.edu