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From: ins845b@monu4.cc.monash.edu.au (mr  k.l. lentin)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: "darkening" colors on VGA cards?
Message-ID: <1991Jun12.062308.24017@monu0.cc.monash.edu.au>
Date: 12 Jun 91 06:23:08 GMT
Article-I.D.: monu0.1991Jun12.062308.24017
References: <1991Jun11.132516.5643@ira.uka.de>
Sender: news@monu0.cc.monash.edu.au (Usenet system)
Organization: Monash University, Clayton, Vic 3168, Australia
Lines: 20

In article <1991Jun11.132516.5643@ira.uka.de> s_rohrbacher@iravcl.ira.uka.de writes:
>Hi!
>
>Is there a way to compute to a given color a darker one on a VGA card (256
>color modes preferred)?
>E.g., given "white" as input, the algorithm should output "gray" and so on.
>Up to now, I'm using an ad-hoc lookup-table, but this approach relies on the
>standard palette...
>
>*ANY* ideas welcome,
>

Try subtracting a constant amount from all three colour planes or reducing
them by a percentage. This will maintain the colour and adjust the brightness.

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