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From: russotto@eng.umd.edu (Matthew T. Russotto)
Newsgroups: comp.sys.mac.programmer
Subject: Re: greyscale video device driver
Keywords: quickdraw, rom, device, driver
Message-ID: <1990Dec2.071510.23820@eng.umd.edu>
Date: 2 Dec 90 07:15:10 GMT
References: <3936@syma.sussex.ac.uk>
Sender: news@eng.umd.edu (C-News)
Organization: College of Engineering, Maryversity of Uniland, College Park
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In article <3936@syma.sussex.ac.uk> robdu@syma.sussex.ac.uk (Robert James Duncan) writes:
>I am writing a driver for a greyscale video device and I need to know
>how to inform Quickdraw that there is only one output channel instead of
>the normal three (red, green and blue).
>
>If I had a fixed linear ramp of greys, then I suppose I could specify
>that I was a direct device with each 8-bit pixel consisting of one 8-bit
>component.  Does any one know whether this will work, or how to specify
>greyscale for a writeable clut, i.e. an indexed device?

Can you just set the gdDevType bit of the GDflags of your GDevice to 0?  
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.