Roto circle not perfect

[ghost]

Using Natron 2.1.7 Release on Ubuntu 16.10

Pressing SHIFT while dragging a roto ellipse should result in a perfect circle. I just noticed it does not, it is close, but not perfectly round between the four control points.

[devernay]

The bezier control points should be:

P_0 = (0,1), P_1 = (c,1), P_2 = (1,c), P_3 = (1,0)

with c = 0.551915024494

See http://spencermortensen.com/articles/bezier-circle/

Alex, can you plz check and put that reference in the code?

[devernay]

btw, if you want real circles with proper antialiasing, the Radial plugin from Natron >= 2.1.8 is the way to go (set softness=0)

[devernay]