Qt::WA_AlwaysStackOnTop influences font rendering in QML

Frime

Hi together,

I need a transparent QQuickWidget embedded in an QWidget UI. But to get this widget transparent, i have to set the window attribute "Qt::WA_AlwaysStackOnTop". But this influences the font rendering in Ubuntu.. There is no anti-aliasing anymore. If i comment this out, i have a black background (instead of transparent) but a nicely rendered font.

Does anybody has an idea?
Thank you very much in advance!
Frime

Prezes

Add:

setClearColor(Qt::transparent);

Frime

Thanks for your response. But this is already done.. the window attribute "Qt::WA_AlwaysOnTop" has to be set in addition. "setClearColor(Qt::transparent)" only has no effect without this attribute..

Ilf i comment this line (setWindowAtttribut(Qt::WA_Alw...)) out, the the fonts are rendered with anti-aliasing but the background has no transparency anymore. Otherwise, the background is transparent but the fonts are rendered pixelated..

Any ideas?
Thank you very much in advance,
Frime

Prezes

@Frime

Yes you're absolutely right! I have the same problem with this and I don't find any satisfaction solution.
I suppose this is a bug from Qt.

I made this in this way:

view = new QQuickWidget(this);
view->setSource(QUrl(QStringLiteral("qrc:///qml/vs.qml")));
view->setClearColor(Qt::transparent);
view->setAttribute(Qt::WA_AlwaysStackOnTop);

But this is not solution.

Frime

Yep, seems like a Qt Bug :/

My (unsatisfying) workaround: "copy" the background. In my case, I just have a pixelated background-texture I can use as background image.

But this should work also to fake a transparent QML Widget:
Grep the background and provide it via property binding to your QML world. Then you can set it as background-Image in QML.
This could help: http://stackoverflow.com/questions/10381854/how-to-create-screenshot-of-qwidget Not nice, but should work.

Best,
Frime