Is your feature request related to a problem? Please describe.
I'm trying to pixelate an image with a transparency. Instead of blending the transparency with the edges, the edges become white/black and non-cubic.

e.g.

Describe the solution you'd like
I'd like cubic edges (not the current shape outline), with the transparency incorporated into the pixelation (instead of white/black), similar to Gimp's Pixelize - screenshot below (ignore the yellow outline).

Describe alternatives you've considered

I've considered writing my own pixelate function using getBuffer.

I've attached the original chicken image for reference.

(For my reference - #316 (comment) )