custom region shape and fill color pixelation

**Is your feature request related to a problem? Please describe.**
blurring faces with pixelating always block shape(square, rectangle), and can't really choose a different color i.e black, green etc.
**Describe the solution you'd like**
ability to set the shape of the region, i.e circle or custom shape(contour of the face). And the ability to set choose the fill color and/or control the fill color
**Describe alternatives you've considered**
Sharp js