slow ui.cameraView->setPixmap(QPixmap::fromImage(img));

[bhamadicharef]

Hi

Working with Qt 4.6.3 on an embedded system. Get some data from camera sensor
and saved in a QByteArray frame. Due to image format differences I convert the
data into a QImage img which is using the following for rendering onto a QLabel.
ui.cameraView->setPixmap(QPixmap::fromImage(img));

When I time this last line of code, for large resolution (640x480) it is very slow
and limit the performance severely in terms of fps (frame-per-second).

Are there any tricks / ways in Qt to accelerate this rendering aspect ?

Thank you very much in advance for your time and help.

Brahim

[mvuori]

I don't know why that is, but one thing that I would check is that the QImage and that system's QPixmap are in the same format. If they are not, perhaps you could construct your QImage to the label's format, thus skipping a need for format conversion. Another thing could scaling. If your QImage is not the same size as the label and setPixmap does the scaling, you could perhaps use a faster scaling routine, or create the QImage exactly to the desired size (if it is 1 pixel row off, there might be resampling...).