Display only PNG image on desktop

[mchara]

HI,
note QPixmap::grabWindow
and ScreenShot Example,
u may cheat to have the same effect by grabbing desktop under your window and paint your png on background, that is copy of desktop.
Many applications do so(especially older) -it can be seen when moving a window or changing something in background because some of applications grabs desktop only once.

i also read posts on this forum, that shows setMask works also for mainWindow's (mainly related to rounded corners of communicators).
almost forgot, did you checked autoFillBackground property of your window?

there's also Shaped Clock example in qt manual that does exactly what you need...

[marcel]

I must say, that approach is the worst there can be... From the performance point of view and architecture,in general.

The best solution that was implemented so far is kernel_panic's QSkinWindows classes. You can find them in the Qt Software section.

[wysota]

The best would be to use ARGB windows, but I don't know if Mac supports such things. It'd probably require diving into cocoa or carbon.

[THRESHE]

I've read the thread but I didn't understand is it possible to draw semi transparent shadow on a desktop with Qt ?

[The Storm]

Before 2-3 years when I was tring differend cross-platform GUI libraries I saw a module to wxWidgets library that make this thing damn easy. You just choose an png image and set it to specific class offered by that module and you get just the image without anything else, the cool here is that if the image have transparent part inside him you will see the desktop behind and if you righ click on this transparent space inside the image you will get the windows desktop menu(refresh, properties, etc) so basicly on that part there in no anything at all, the guy that created that module showed some pictures - on Windows XP, Linux/X11 and Mac OS X, it was working in the very same way. So I think that this is possible to be done and in Qt. Here is the webpage with screen shots - http://www.upcase.de/wxSkin.html
Look at the the 4 screenshot, on the head of the buddy there is empty space inside the image and there you can get the OS right click menu. And don't think that thats are just screenshot to WMP, the guy just is using their images, I can confirm it because the examples from witch are taken the screenshots comes with the module, so you can compile and see them for yourself.

[wysota]

To me it seems it is using masking. See QWidget::setMask(). How did you say that? "Damn easy"... so damn easy it is and without any extensions.

[The Storm]

I know that without this module it will be hard but it seems that if the TT guys want, they can make it too.

[wysota]

but it seems that if the TT guys want, they can make it too.

What do you mean?

[The Storm]

I meant that maybe TT(TrollTech) can make something like function in to the QWidget maybe to set image to be the only showed thing, and the other parts to be transparent so the effect will be more easy reached, without playing with setMask().

[jpn]

Does it really need to be easier than

label->setPixmap(pixmap);
label->setMask(pixmap.mask());

label->setPixmap(pixmap);
label->setMask(pixmap.mask());

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?

[The Storm]

Then what is the problem of the whole topic huh? Maybe I missed something again... :}

[jpn]

Well, there's a significant difference between masks and ARGB windows. Masking makes completely transparent parts being treated as "holes" whereas ARGB windows can have semi-transparent areas where the desktop shines through. The wxSkin stuff seems to use this masking technique.

[The Storm]

Thanks now I understand the problem of the topic.