tkinter: Round Button - Any idea?

[akineko]

Hello everyone,

I'm trying to implement a virtual instrument, which has buttons and
displays, using Tkinter+Pmw.
One of items on the virtual instrument is a round button.
This is imitating a tact switch.

Tkinter has a Button class, which I can assign a button image.
However, when the button is depressed, the rectangle is sunken (rather
than the round button).

Probably I need to prepare two images, normal one and depressed one,
and implement all button behaviours by myself.
But before reinventing everything by myself, I'm wondering if there is
an easy way to implement or there is existing widget example of such
button.
So far, I couldn't find any good examples.

Any suggestions are highly appreciated.

Best regards,
Aki Niimura