[Solved] Performance QLabel

[ephe]

I'm trying to test the performance of the text drawing of Qt.

In our application we need to update up to 10 values around every 200 ms.
Therefore I created a test application which consists of 32 Labels aligned in a GridLayout (which is set to the central widget of the main window). They are updated with random values every 200 ms.

@
QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(UpdateLabel()));
timer->start(200);
@

@
void MainWindow::UpdateLabel()
{
m_poLabel1->setText(QString("%1").arg(rand()));
//....
}
@

Now the CPU loads seem to be quite high, when I draw it with OpenGL, it the CPU 1 load is around 20, the CPU 2 load is around 35.
When drawing it with the raster engine, the CPU 1 load is around 10, the CPU 2 load is around 45.

I replaced the QLabels with an own widget which holds a QStaticText (even though it says in the documentation that this should be used when the text and its layout is updated rarely). But the CPU 1 load is around 17 and the CPU 2 load is around 25.

Now I wanted to know if there is a way of improving the performance of the drawing of the texts?

If you need some further information or more code please tell me.

[Peleron]

May be each change of labels text invoke recalculation positions of all other QLabels, because GridLayout adjust cells width.
Try to set fixed size of QLabel's

[ephe]

That improved the performance a lot. Thank you!