Re: [Qemu-devel] [SDL] Problem with mouse grabbing

[Greg Alexander <yakovlev@grandecom.net>]

QEMU Needs to grab the mouse because it emulates a real mouse, instead 
of using a pseudo-mouse driver.

As a result, mouse scaling will always be a problem, since all the user 
has to do is change the mouse scaling in the host OS to cause problems 
with the tracking (the scaling problem you noticed.)  That's not to 
mention if the mouse came in somewhere different from where it left. 
There's nothing to cause the emulated mouse pointer to move to the 
position where the real one entered the QEMU window.


GREG

Jim C. Brown wrote:

> Why does qemu grab the mouse? Sometimes, when it is closing, I will
> forget to press Ctrl-Shift, and the mouse ends up being unusable.
> 
> This got very old in a very short amount of time, so I edited sdl.c to simply
> "follow" the X mouse pointer, ala VNC-style, and it works. There is a strange
> bug, but aside from that it works perfectly. I find this more convenient
> for handling the mouse. My question is: why does qemu grab the mouse pointer
> instead of just following it? Is this for technical reasons or just because
> the VM looks nicer that way?
> 
> P.S. The strange bug is simply that the virtual mouse pointer moves a little bit
> faster than the real mouse pointer. It's annoying but still usable, although
> it does cause the virtual mouse pointer to show up in odd places every now and
> then.
>