How to avoid white artifacts when use translucence attribute?

Question

I want to make a translucent window in Qt:

setWindowFlags(Qt::Popup| Qt::FramelessWindowHint);
setAttribute(Qt::WA_TranslucentBackground,true);

But Once I set the Qt::WA_TranslucentBackground to true, there will be white things on the four corners of each widget:

It appears whenever the mouse hover though the widget,or click on it. How to avoid this ? If I set the Qt::WA_TranslucentBackground to false, the problem will be gone. But I need transparent window. Thanks beforehand!

Answer 1

I worked it out myself. There are two reasons together that make these artifacts happen: I have turned on the translucence background for the window ,and use QPainter to manually draw the window's rouned-corner background . When the mouse hover/press on the Children widgets, the update(QRect) the widget sent to window widget does not compute the background well.

When I use stylesheet to draw the background, problem solved :)