Transparent windows?

[wysota]

QWidget::setMask() may be able to help you, it doesn't use the composite capabilities of your graphical backend. It won't help you to achieve semi-transparency, though. You'll need composite for that (or you'll have to "emulate" it, which will be very inefficient).

[yogeshm02]

Composite is what I am thinking, since months, I need. But owing to no documentation (at I could not find) I am unable to use it. Also I am pretty my uninformed about what exactly needs to be done for the task on hand.

[yogeshm02]

Somewhere in my is this idea: Use composite for a screenshot of each window and blend with my window.
This, for me, is very ugly idea (and perhaps would be slow), but I've no idea of how composite functions or what it can do or not.

[wysota]

AFAIK composite works as described in the article already pointed in one of the previous posts in this thread. Search Google for composite+extension+x11+api, maybe something usefull will pop up.

[pherthyl]

QWidget::setWindowOpacity(qreal)

Or am I misunderstanding your question? That function will set your window partially transparent (provided composite is working).

[wysota]

QWidget::setWindowOpacity(qreal)

Or am I misunderstanding your question? That function will set your window partially transparent (provided composite is working).

It won't work for X11 and additionally it changes the opacity of the whole window, not parts of it.

[pherthyl]

It won't work for X11 and additionally it changes the opacity of the whole window, not parts of it.

Indeed. But you won't get around the requirement for composite no matter what you do (unless you just want to mask, or use some very ugly screenshot hacks).

However, at one point I remember zack rusin (Trolltech and KDE dev) releasing a short video showing what the SVG engine in Qt is capable of. In this video, he had a toplevel widget, defined in SVG, that was partially transparent (but only parts of it) and could add standard widgets on it. Now I can't find this video anymore, but it seems that it should be possible to do what the original poster wanted in this way.

[pherthyl]

Found it:

http://www.kdedevelopers.org/node/1559

It seems this should be possible right now? I'll have to try and get back to you.

Update: Can't get it working here (4.1.3, Windows XP). I emailed Zack about it, see if he can provide any details.

[yogeshm02]

Found it:

http://www.kdedevelopers.org/node/1559

This is exactly what I want! Looks too easy.

Update: Can't get it working here (4.1.3, Windows XP). I emailed Zack about it, see if he can provide any details.

My initial attempt has also failed. I'll try different combinations and report if done.

[pherthyl]

No success here. I can't get it to work, and I haven't heard anything from Zack. I suspect this feature either never made it into Qt, or didn't make it until 4.2, or didn't make it into the Windows version at all.