How do you make a game do this?

[spoon licker]

I wanna make a game where the window grows and shrinks to throw the user off.

But it has to grow in a circle not a rectangle. Like I want a circular window form not rectangle one.

[eypros]

I am not sure you can find many libraries offering this functionality.

Anyway what library do you use?

[Mats]

Why make the game window do that? You could just put the game in full screen mode and make a 'window' in game that can be any shape and that you can do anything you want with.