Re: Touch support
* 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
> pen.
>
> 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?
Other apps/toolkits/etc have to actively take care of touch support
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.