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Hello,

I'm currently working on a program which displays lots of images on a second screen and uses various GigE cameras to take pictures from each single displayed image.
The second screen is a 4k television. The displaying is done by a single QLabel on a QWidget which is moved and resized to fit the second screen.

Currently I implemented a time delay between displaying and grabbing in order to be sure the screen has fully updated and the image is fully shown.
In order to keep the delay, hence the whole measurement time, at the minimal value possible:

• Can I use the screen refresh rate as an indicator for how long to wait until the cameras can grab?
• Has Qt some functionality which signals me that the label and the screen have just finished to fully display the image? For the screen maybe something like a bypass of a hardware trigger directly from the screen?

Maybe someone has already worked on a similar topic,
Greets