Important: Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

How to Detect Vertical Retraces



  • Dear All:

    I am trying to develop an application for scientific purpose and I need to know exactly when the screen is going to begin to draw again. I think that normally the graphic card send a message call "vertical retraces" to tell the CPU he will begin to draw can someone tell me how to catch listen this from withing Qt?

    All the best and thanks a lot
    Ernesto



  • I think this is more an OS thing to handle. Qt will only get a 'need to redraw' event from the OS. It does not know itself when to redraw. Maybe you could get some information from the OS itself using OS API.



  • Hi thanks for your help I have one more question then. This redraw event will then be synchronize with the "Vertical Retraces" don't it? I mean as far as I understand then Qt will received redraw event each time the OS refresh the screen is my assumption correct?

    Best and thanks


Log in to reply