[Development] QWindowSystemInterface::handleMouseEvent() relative or absolute?

[Johannes Zellner]

Hi,

I am currently working on evdevmouse input fixes for the eglfs usecase.
During the testing I had two mice in parallel .
I saw that each mouse maintains its own position on the screen, because the
QWindowSystemInterface::handleMouseEvent() takes only absolute coordinates.
Wouldn't be relative coordinates better? 

Its hard to fix the issue of multiple mouse input devices, because the 
evdevmouse plugin itself could manage the coordinates and sync between 
multiple devices handled by the same plugin, but if the pointer position is 
manipulated by two different plugins we have a problem.

This might be already discussed but I could not find an answer, why we choose 
to use absolute coordinates here.

Thanks,
Johannes