Help about special effects while closing widget window.

Hi,
I am swapnil I want to give special effects to my window while closing.
Such as
1) Closing application window by rotating clockwise when user clicks close button.
2) Giving conicalgradient effect while closing window clockwise.

I am using qt4.6 and ubuntu 10.04 linux. I want to do this all in paintEvent or in any other method.
Please help me in how can I do this.
Thanks.