Arc shape

Jeff Martin jeff at
Wed May 2 09:06:15 PDT 2012

I think rotation is following the right hand coordinate system (or right hand thumb rule) with positive z coming out of the screen.

The StartAngle also seems to be working correctly according to a sanity test I just did. The start angle defines where the angle starts so it doesn't effect (and shouldn't be subtracted from) the arc length.


On May 2, 2012, at 7:26 AM, goddard at wrote:

> Hi,
> I've got this constructor for an arc:
> Arc a = new Arc(100f, 100f, 50f, 50f, 0f, 120f); //cX, cY, rX, rY, angle,
> length
> That produces the visual output you can see in the attached screenshot.
> My questions are:
> - if the 0 degree starts at X axis, then why?
> - if an arc is extended counter-clockwise, then why?
> Does it ignore the startAngle completely?
> Arc a2 = new Arc(200f, 100f, 50f, 50f, 120f, 240f); //produces an arc of length 240, instead of 120?
> There're other things/properties that are designed to use the clockwise system
> (top, right, bottom, left) in JavaFX, therefore this makes a programmer to
> "switch" between these two concepts, in addition to all the other things one
> must remember.
> I think we had similar discussion during JavaFX 1.2 or 1.3 development...
> Regards, Jiri

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