Blocking mouse on entering non reachable areas in multi-screen setups

[todd rme]

On Thu, Sep 23, 2010 at 2:20 PM, Martin Gräßlin
<kde at martin-graesslin.com> wrote:
> On Thursday 23 September 2010 16:30:41 todd rme wrote:
>>  I think a good solution integrated
>> into KDE by default is a must-have.
> No, this is a must-have for X. We as KDE should not dare to implement
> something like that. The probablity to get it wrong is very, very high. And
> the chances to get it somewhat working is very, very low. Getting this wrong
> would be a bigger desaster than the current sitiuation and yes it sucks and
> yes I myself have such a setup. Furthermore it would just be bad for the
> complete freedesktop if we did a solution which could not easily be reused by
> the other desktops (GNOME, XFCE) and yeah for them a Qt dependency would mean
> unusable :-P
>
> So if we want to fix it, it needs to be done on X, but even there I think it
> is an unfixable issue (just imagine two screens with a gap between them, how
> do you want to recognize that), or somethin like that:
>
> ----------------------
> |           |                |
> | A        |___ B___ |
> |_____ |____
> |                    |
> | C                 |
> |__________|
>
> (I hate ASCII art)

There is already a tool called noenter that worked pretty well, but it
won't compile.  At the very least fixing that and letting people who
want to compile it themselves would be nice.

But, since noeneter works, it is possible to detect where invisible
portions of the screen are.  And, from what someone said in the other
thread, it is possible to teleport mice.  So the remaining question is
whether it is possible to detect whether there is a screen on the
other side of a blank portion.  If there is, then it should be
possible to handle the situation you describe.

-Todd