[PyQt] QSplashScreen with transparent background

[David Boddie]

On Tue Mar 24 00:18:54 GMT 2009, Saúl Ibarra wrote:
 
> I'm sure this question has been answered many times, but I'm not able
> to achieve what I want :-/ I just want a splashscreen with a single
> png with transparent background.

Is this on Linux/Unix?

> I'm using the following code:
>
> pic = QtGui.QPixmap(":splash/images/splash.png")
> splash = QtGui.QSplashScreen(pic)
> splash.show()
>
> I know the issue has to do with the alpha channel, but can't get it
> working...

On some platforms, there are issues with the display system. This is covered
in the "Translucent Widgets in Qt" article in the latest Qt Quarterly:

  http://doc.trolltech.com/qq/

Basically, you need to be running a compositing window manager. More details
can be found here:

  http://doc.trolltech.com/4.5/qwidget.html#windowOpacity-prop

If you can't guarantee that users will have systems with this feature
enabled, you can always fall back to an approach where you fake a transparent
background. This is done by grabbing the screen with QDesktopWidget the way
the Screenshot example does, then drawing on it and cutting out the part you
want to display.

I believe this is way the Qt Jambi demo launcher does it, though it also does
some fancy things like blurring the background image.

David