X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com Message-ID: Date: Sun, 27 Nov 2011 22:36:03 +0100 Subject: [geda-user] Mathematics of the arc element in pcb. From: myken AT iae DOT nl To: geda-user AT delorie DOT com User-Agent: SquirrelMail/1.4.21 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal Reply-To: geda-user AT delorie DOT com Hello all, I'm working on some functionality in pcb and I have a question. The question is about the start angle and the delta of an Arc element in pcb. If I draw an Arc in pcb then I will get the following entry in my pcb file: Arc [X Y Width Height Thickness Clearance StartAngle DeltaAngle SFlags] (no not literally but I hope you know what I mean ;-). If the Width and the Height are the same the start angle (45 degrees) and the delta (90 degrees) work as expected, Arc[200000 150000 20000 20000 100 200 45 90 "clearline"] But if the Width and the Height are not the same, it looks like the start angle and the delta are totally ignored. Arc[200000 150000 30000 20000 100 200 45 90 "clearline"] Can anyone explain to me the mathematics behind the Arc element or point me to the source code that does the mathematics? Thank, Robert.