Cairo has an issue a drawing thick line and a very specific transform matrix

[twilson90]

Sample code:

import openfl.display.Sprite;
import openfl.Lib;

class ClippingTest extends Sprite {
	public function new() {
		super();

		graphics.lineStyle(50, 0, 0.5);
		graphics.beginFill(0xff0000);
		graphics.drawCircle(150, 300, 100); // edges cut off
		graphics.endFill();

		graphics.lineStyle(1, 0x00ff00);
		graphics.drawCircle(150, 300, 125); // this draws correctly!
		scaleX = 2.7925;
		scaleY = 0.3575;
	}
}

I suspected the size of the surface / bitmapdata the graphics is drawn to was incorrectly calculated by OpenFl, but that's not it.
As you can see on the same surface I draw another circle (outlining the area of the first circle) and it is not cut off on the edges.

If I set scaleX or scaleY slightly differently (+/- 0.02) then it draws correctly.