[PATCH inputproto XI 2.2] Set a flag on the pointer-emulating touch event

Peter Hutterer peter.hutterer at who-t.net
Mon Jan 2 18:00:24 PST 2012


On Mon, Jan 02, 2012 at 05:55:47PM -0800, Chase Douglas wrote:
> On 01/02/2012 03:29 PM, Peter Hutterer wrote:
> > Toolkits need to know which touch event emulated a pointer event and which
> > ones do not. To quote Carlos Garnacho:
> > 
> >     GTK+ does client-side windows by default (GdkWindows without a backing X
> >     window), for this to work the toplevel window in the client needs to
> >     select for more events that it wouldn't normally select for in order to
> >     cater for the event masks in such child "windows". This means that
> >     ideally GTK+ should set the touch events mask in the toplevel, and then
> >     find out whether the "window" would receive pointer or touch events for
> >     the sequence emulating the pointer, and perform the emulation itself.
> > 
> > Reported-by: Carlos Garnacho <carlosg at gnome.org>
> > Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> > ---
> > IIRC we did discuss this months ago and decided not to set the flag but the
> > above use-case cannot easily be solved right now. Adding this flag in the
> > server is simple enough.
> > 
> >  XI2.h              |    1 +
> >  specs/XI2proto.txt |    8 ++++++--
> >  2 files changed, 7 insertions(+), 2 deletions(-)
> > 
> > diff --git a/XI2.h b/XI2.h
> > index 4368006..e864b06 100644
> > --- a/XI2.h
> > +++ b/XI2.h
> > @@ -158,6 +158,7 @@
> >  #define XIPointerEmulated                       (1 << 16)
> >  /* Device event flags (touch events only) */
> >  #define XITouchPendingEnd                       (1 << 16)
> > +#define XITouchEmulatingPointer                 (1 << 17)
> 
> Is this easier than having a dual-purpose XIPointerEmulated flag? We
> would have to push XITouchPendingEnd to the 17th bit, but an ABI break
> right now isn't too bad.
> 
> Or, do you have a specific reason why we shouldn't reuse the flag?

yeah, to avoid confusion. XIPointerEmulated and XITouchEmulatingPointer have
exactly the opposite meaning, so I'd rather have the two with different
names.

Plus, we get semi-namespacing this way too for the flags.

Cheers,
  Peter


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