Input Event Handling
Thorsten Wilms
t_w_ at freenet.de
Wed Apr 4 13:13:33 PDT 2007
On Wed, Apr 04, 2007 at 10:14:24PM +0300, Daniel Stone wrote:
>
> Hi,
> Input focus is to a particular window, so you get device -> kernel -> X
> server -> app.
There are cases like sliders in a windows with scrollbars. With
gtk+ at least, if the pointer is on the slider, mouse-wheel will
move the slider. But with the pointer anywhere else, the wheel
scrolls.
Does this mean that input focus has to be redone on the window/
application level for things like this to work?
> > Does the x-server anything special to receive all input events?
>
> Yes, google for "x11 grab", or man XGrabKeyboard.
Ah yes, XGrabKeyboard does it :)
> > Does the kernel have a concept like input focus?
>
> No, it just sends events to /dev.
There must be some mechanism for only letting a cli app in the
current virtual console receive input events.
> This is another special case: you can grab particular _keys_. So if you
> want Alt-F10 to maximise in the window manager, you set a grab on F10
> and check if Alt is also pressed. If not, you let the event go through
> to its original destination (i.e. the window with input focus), else you
> intercept the event and maximise the window.
So commonly WMs set grabs on ther shortcuts, while application just
wait and see what comes?
Thank you very much for the info!
--
Thorsten Wilms
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