Quality of drawn shapes

[anthony]

The circle seems perfect it me, for a very thin stroke width, which is producing a slight beat in the anti-aliasing as the line moves from one pixel to the next.

Try using a slightly thicker minimum stroke width, say 1.3, which will reducing this anti-aliasing 'beat'.

If this does not solve the problem, produce an exact equivalent image in the other package for comparison and show use both images together.