# of overlay planes

[Dan Christensen]

In article <8908161833.AA12079 at castor.wustl.edu> weinhous at CASTOR.WUSTL.EDU ("Martin S. Weinhous") writes:
>  Many image processing systems, particularly those intended for the
>processing of gray-scale images provide the capability of using 8 bit
>planes of overlay.  This allows the user to, easily,  non destructively,
>annotate the gray-scale images with up to 256 colors.  I'd like to do
>the same on my 4D120-GTX, but can't.

You should be able to use colour map mode and writemasks to achieve
what you want to do.  How many bits do you need for the gray scale?

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Dan Christensen, Computer Graphics Lab,	         jdchrist at watcgl.uwaterloo.ca
University of Waterloo, Waterloo, Ont.	         jdchrist at watcgl.waterloo.edu