wxBitmap透明背景

Question

I have a wxBitmap which can be hidden or revealed on a wxPanel. When the wxBitmap is hidden I would like it to have the background of the wxPanel, instead it has a standard grey background.

To illustrate my point here are two images:

Bitmap shown: http://i.stack.imgur.com/PzpR9.png

Bitmap hidden: http://i.stack.imgur.com/GWs7r.png

I tried applying a mask and using alpha channel for transparency, but these do not solve the problem. What I need to do is set the background of the wxBitmap.

Any ideas how I can accomplish this?

Answer 1

I have noticed that if I minimise the window and then show it again, the problem is solved - no default grey background when the bitmap is hidden. I do not know what operation this (minimise + maximise) procedure performs and I have not yet figured out how to implement it programmatically.