View Full Version : QT QML/C++ translucent window has glitches and performance problems on Mac OS X

5th May 2011, 10:00
Hi all,

I've developed a QT/QML application which I display with a translucent QDeclarativeView in a translucent frameless QMainWindow (see this). The application is fairly complex with a a few ListViews inside and some threads that poll a remote server for data and feed the views. The program runs flawlessly and at full speed without glitches on Windows 7. But when I compile and run it on Snow Leopard I've got the following problems;

GUI rendering is slow in general
When I scroll the ListView with the mouse wheel, the wheel actions affect the underlying window and my GUI flickers as if it can't render fast enough. Also often when I click something on my GUI, the mouse click just passes through my window onto the underlying window and brings it in front.
Mouse actions feel awkward. There is a significant delay.
These problems are present on both the Release and Debug builds with/without gdb attached.

The problems sound related to me but I'm confused. Why would an application running perfectly on Win7 perform badly on Snow Leopard ? Am I missing some specific configuration ? Any help is appreciated.

12th May 2011, 16:26
I have placed a bug report regarding the issue. There is also a minimal sample attached. http://bugreports.qt.nokia.com/browse/QTBUG-19235

6th June 2011, 12:36
I have added videos of the problem to the bug report. Could anyone check and make comments perhaps ?

8th June 2011, 21:24
Try run application with option -graphicssystem raster (or -graphicssystem opengl), or use static function QApplication::setGraphicsSystem.