Producer Consumer

[jacek]

The code of the Widget is executed by the Consumer Thread. It Process the image, take the result image and display it.

And that's the problem. Only the main thread (a.k.a. the GUI thread) can touch the GUI. Better send those QImages through a queued connection to the GUI thread and let it handle them.

Also read this carefully: http://doc.trolltech.com/4.2/threads.html