http://www.perlmonks.org?node_id=287298


in reply to Non-rectangular mainwindow

As proof of concept this awful following script
which map a flower with transparency (if you wait a bit).
For sure if you only want no-rectangular corners, you just need
work out that.

As each pixel is hard coded, the script is very long.
Hope this help.

Update
For Perlmonks HD space consideration I link this out:
Transparency