Dear all,

I have a full screen main window P (parent widget) showing an image using paintEvent(). A child widget C is attached to this main window and calling its own update() periodically. It seems that once the update() of C is called, the paintEvent() of P gets called as well, which consumes a lot of CPU (on Ubuntu X11).

Because C may have (semi-) transparent colors, I cannot set Qt::WA_OpaquePaintEvent attribute for it. Is there any other way to prevent calling P's paintEvent() or to reduce the CPU consumption substantially?

Thanks in advance for any suggestions.