kwindowsystem crashes

[Kurt Hindenburg]

There are a number of lines that division by zero could happen in frameworks/kwindowsystem/src/platforms/xcb/kwindowsystem.cpp  if displayGeometry returns a 0 QRect.  I think that is what is happening with bug 349512.

viewportToDesktop, viewportWindowToDesktop, desktopToViewport

I’m not clear on the best way to prevent this.  Forcing displayGeometry to never return a 0 QRect (which seem the best) or by checking all the locations of division by 0.  

Any suggestions or comments? 
   Kurt