title: Using Qt with XVisibilityEvent?
body: <p>I am having a Qt (5 &amp; 6) application (primarily using custom OpenGL for rendering). And I would like to optimize it a bit by not rendering at all when the window is either hidden or fully occluded.</p>
  <p>This seems to be possible via <code>XVisibilityEvent</code> on X11 platforms (Xlib &amp; xcb with expose that event), but seems like Qt does not forward this functionality.</p>
  <p>Now I wonder if it's possible to tell Qt, when running via xcb platform plugin, that I'd like to also get notified on the above event.</p>
  <p>I am very well aware of the fact that this will only work on X11 platforms, but I'd like to get such a functionality first running on X11 and then see if it might be possible on other platforms (Wayland/Win32/OSX) as well.</p>
  <p>Reference: <a href="https://www.x.org/releases/current/doc/man/man3/XVisibilityEvent.3.xhtml" rel="nofollow noreferrer">https://www.x.org/releases/current/doc/man/man3/XVisibilityEvent.3.xhtml</a></p>