On Thu, Mar 02, 2017 at 08:46:11PM +0100, Florian Weimer wrote:
* Carlos Garnacho:
> Hi Florian,
>> I have a touch screen which generates a plethora of event types
>> according to libinput-debug-events (including what seems to be
>> multi-touch events). I can even see distinct events for the digitizer
>> However, further up the stack, all this is gone. I don't get any
>> two-finger scrolling, for instance. There is no right-button
>> emulation in Firefox, either. I can still generate primary button
>> click events and (single-finger) drag events, but that's about it.
> Handling of touch events is up to the application. Besides the minimal
> single-touch to pointer event emulation (which only applies to
> X11/Xwayland) there are no emulation layers making this up for
> applications that don't know about touch events themselves.
Wow. Doesn't that make it rather unlikely that touch behavior across
applications remains consistent?
in the short-term, yes. in the long term we hope to be fine, mostly because
there are only a few gestures that are easily discoverable and commonly
But in any case, our hands are tied because only the application has
sufficient context to handle direct-touch correctly to e.g. distinguish
between a two-finger scroll gesture or a "move two icons at once" gesture.
This is different to a touchpad, where it's less ambiguous.
> Other apps/toolkits/etc have to actively take care of touch
> themselves. Firefox, despite "using" GTK+, implements itself large
> parts of their UI, if they don't observe touch input, it's pretty much
> for them to make use of it too.
Firefox turns on touch support only when the per-tab subprocess mode
is active (i.e., browser.tabs.remote.force-enable is set to true).
This is not the default in Fedora.
This Firefox mode provides drag-scrolling (before, dragging only
selects text), and it is also possible to open links in a new tab
because a long touch on a link triggers the context menu.
However, this works only once. After creating a new tab in this
manner, touch events only move the pointer as far as Firefox is
concerned, but do not result in click events, so it is no longer
possible to interact with the Firefox application. I'll file this as
a bug (unless this is a known issue).
>> With Wayland, the pen appears to be completely dead. With X, I get
> Can you interact with gnome-shell with it? or is it entirely dead?
Not sure. There is some pointer activity in response to the pen: a
second pointer appears, but not necessarily at the tip of the pen. So
it's not completely dead.
Wayland has different graphics tablet handling than X, specifically it has a
separate focus and can thus be provided a separate cursor. What you're
seeing is default behaviour. The big problem right now is that XWayland
doesn't support tablets yet (patches floating around on the list) so the
events just disappear into nirvana and/or valhalla, whichever comes first.
However, the second pointer should be at the tip of the pen, if not we have
a calibration issue - please file a bug for that.