Draw a circle or an arc circle according to the related material.
Transparency is supported (Extra processing power will be used when animating
radius or angles with transparency > 0).
When -2*PI < arcAngle < 2*PI, the resulting arc begins at
startAngle and extends for arcAngle radians.
Angles are interpreted such that 0 radians is at the 3 o'clock position.
A positive value indicates a counter-clockwise rotation, while a negative value
indicates a clockwise rotation.
SFFloat radius 1:
Circle radius in pixels.
SFFloat startAngle 0:
Start angle of the arc in radians. The above rotation transformations also apply
to this value but only for multiple of PI/2.
SFFloat arcAngle 0:
Angle of the arc in radians.