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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: hacknews
Subject: plotter circles and arcs speeded up
Message-ID: <4160@utzoo.UUCP>
Date: Tue, 31-Jul-84 17:03:17 EDT
Article-I.D.: utzoo.4160
Posted: Tue Jul 31 17:03:17 1984
Date-Received: Tue, 31-Jul-84 17:03:17 EDT
Organization: U of Toronto Zoology
Lines: 14

The plot(3) software for the HP plotter has been improved to do small
circles and arcs more quickly.  It now exploits the obvious fact that a
very small circle doesn't need to be drawn as a 72-sided polygon to make
it look like a circle.  The "chord angle" parameter of the plotter's
circle and arc commands is now a function of the radius of the circle,
with reversion to the 5-degree default for large circles.

Arguably the plotter ought not to revert to the default for very large
circles, since they do look slightly better when drawn with a smaller
chord angle, but doing this makes them very slow.  The default is a good
compromise for the big stuff.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry