Fast Timer Updates vs. Monitor Refresh Rates

[tbscope]

You do not need to get the signal from the display. OpenGl has a function that does that for you.

What I would try to do:
Create a graphicsview that contains the user interface. Make it so that everything inside the graphicsview is painted via OpenGl
There are lots of tutorials in the Qt labs and documentation.
And then use the information from the blog post about blocking the eventloop and synchronising the eventloop to the refresh rate of the monitor.

If you use a graphicsview and opengl, the effects possible with your user interface are infinite, although limited to the contents of the graphicsview.

Edit:
Here's a nice example:
http://labs.qt.nokia.com/2008/06/27/...s-with-opengl/

Edit 2:
You need this function:
http://doc.qt.nokia.com/latest/qglfo...etSwapInterval
Set it to 1

Tip:
QML does this out of the box. It's worth studying the code.