Article View: fa.info-mac
Article #1605Re: Quickdraw Regions Explained
From: info-mac
Date: Fri, 01 Feb 1985 12:06
Date: Fri, 01 Feb 1985 12:06
17 lines
1155 bytes
1155 bytes
From: Bob Cralle <cralle@lll-crg.ARPA> Why not encode a circle using Minsky's algorithm?k x(n+1) = x(n) - k y(n) y(n+1) = y(n) + k x(n+1) [x(n+1) is intentional, else spiral] k is small const. Negative power of 2 is nice. x(0) = radius (y(0) = 0). This scheme makes best circle (actually it's an ellipse). I found that it also makes nice ellipses if 1st k = ke & 2nd k = k/e, where e is the eccentricity. Pretty compact encoding: center of circle & small const. Regards, Bob p.s. I wrote a couple of short notes on this subject. If interested I will send.
Technical Details
Message-ID:
<709@uw-beaver>Path:
arc1-ca.pugleaf.net!utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxb!mhuxn!mhuxm!mhuxj!houxm!vax135!cornell!uw-beaver!info-macShow Full Headers
Complete Article Headers
Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site uw-beaver Path: arc1-ca.pugleaf.net!utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxb!mhuxn!mhuxm!mhuxj!houxm!vax135!cornell!uw-beaver!info-mac From: info-mac@uw-beaver Newsgroups: fa.info-mac Subject: Re: Quickdraw Regions Explained Message-ID: <709@uw-beaver> Date: Fri, 1-Feb-85 07:06:05 EST Article-I.D.: uw-beave.709 Posted: Fri Feb 1 07:06:05 1985 Date-Received: Sat, 2-Feb-85 11:57:34 EST Sender: daemon@uw-beaver Organization: U of Washington Computer Science Lines: 17