From: "David Lively" <davidl@keil.com>
Newsgroups: borland.public.delphi.graphics
References: <3b02b68d$1_2@dnews> <3b02bc45$2_1@dnews> <3b02ca8c$1_2@dnews> <3B03861E.585A15FD@biomed.gla.ac.uk> <3b03df2e$1_1@dnews> <3B042BBB.BC6ECC9E@courthouse.com>
Subject: Re: Erasing lines without using Xor
Date: Fri, 25 May 2001 18:04:34 -0500
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If your background isn't complex but you still need control over color you
can use:

DrawColor := BackgroundColor xor DesiredColor;

Then XOR-draw the line using DrawColor as the Pen color.

(BackgroundColor xor DrawColor will give DesiredColor).

Of course, if the line goes over anything where the background color is
different, the line color will shift.

- D