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From: moraes@cs.toronto.edu (Mark Moraes)
Newsgroups: comp.windows.x
Subject: Re: Problems w/XDrawRectangle, rubberbanding
Keywords: XDrawRectangle, rubberband
Message-ID: <90Sep30.183132edt.421@smoke.cs.toronto.edu>
Date: 30 Sep 90 22:33:05 GMT
References: <1990Sep27.161240.14668@swbatl.sbc.com>
Organization: Department of Computer Science, University of Toronto
Lines: 16

I use something like this to create GCs for rubberbanding.

GC
createxorgc(dpy, win, fgcol, bgcol)
Display *dpy;
Window win;
Pixel fgcol, bgcol;
{
	XGCValues gcv;
	
	gcv.foreground = fgcol ^ bgcol;
	gcv.background = bgcol;
	gcv.function = GXxor;
	return XCreateGC(dpy, win, (GCForeground | GCBackground | GCFunction),
			 &gcv);
}