continuous transition for Oval and Rectangular gradients

[zainalara]

Rather than a hard choice between oval and rectangular, would it be possible to
1. Introduce a corner radius setting for the rectangular shape gradient
2. have a continuous control of the shape, for example :
0 = fully rectangular, with rounded corners,
1 = fully oval ;
in-between values = as desired between oval and rectangular

[jsachs]

The Oval Gradient transformation has a Roundness slider already.