XComposite input redirection/transformation proposal

[Dennis Kasprzyk]

Xavier Bestel wrote:

> On Mon, 2008-02-18 at 20:29 -0800, Keith Packard wrote:
>> You need full bijection between every window and the screen coordinate
>> space (expressed as nested bijections between windows and their
>> parents). Otherwise, grabs will have incorrect coordinates (making
>> selections and scrollbars work in 'odd' ways). Fixing drag&drop may also
>> be an adventure.
> 
> I fear it's not possible. Compositing managers allow windows to be
> displayed multiple times (e.g. once in the pager, once normally) and
> some allow even more weird multiple instances of the same window (take a
> look at Metisse). I'm sure one day they'll want to enable input on some
> or all of these instances, meaning bijection isn't an option.
> 
> You could hack around it: when grab starts, identify which instance it
> started from and limit redirection from there. So you'd need bijection
> only during grabs. But it may not always work.

In a previous mail to this thread I've proposed a way how to get "cloned"
windows (InputOnly redirection Windows) and the bijection. But the system
would be more complicated.

- Dennis