[quote author="Gerolf" date="1294907465"]That has a similar effect, but a mask does not make alpha, it makes transparent or not.
A top level widget (QSplashScreen is a widget) can be transparent. Sorry, I didn't read the complete article before. Currently I can't test it, but you could play with the following things:
Thank you for the additional information but unfortunately it seem not to solve my problem:
Makes the complete widget 75% translucent but does not affect the area using the alpha channel.
All tree attributes just make the background of the window black and the area involved depends on the use of setMask.