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From: oster@well.sf.ca.us (David Phillip Oster)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Tracking the mouse.
Message-ID: <21464@well.sf.ca.us>
Date: 2 Nov 90 09:18:10 GMT
References: <1990Oct31.100603.1989@agate.berkeley.edu> <21455@well.sf.ca.us>
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 17

The overhead to call a few traps in a 
	while(StillDown()){
		MoveTo();
		LineTo();
	}
loop is totally lost in the time it takes to actually do the drawing.
The trap dispatcher overhead simply can't matter. You get responsiveness
in a situation like this by:
	draw only that part that changes.
	use XOR mode drawing, so a second draw can erase it,
	or, use an offscreen buffer that you CopyBits to the screen.
Even though the offscreen buffer is actually slower, its smoothness is
percieved by users as being faster. (To get flicker free, stamp your
offscreen bitmap with the image of the cursor.)
-- 
-- David Phillip Oster - Note new signature. Old one has gone Bye Bye.
-- oster@well.sf.ca.us = {backbone}!well!oster