There is annoying interference between formatting the value
(for which we set the number of digits to show) and the small
frame-to-frame value changes that we do for autoscrolling.
To work around this, turn off the digits-based rounding entirely
and format the value ourselves with ::format-value.
And rename it to "Touch and Drawing Tablets", since it's no longer about
"axes" really.
As for pad support in the demo, just keep it "simple", make the
controller handle all pad devices, and make all the actions have the
same callback.
https://bugzilla.gnome.org/show_bug.cgi?id=770026
The wayland tablet protocol allows notifying the compositor with
descriptions of the actions performed by each tablet element. This
API call allows to hook up in to this wayland-specific feature.
https://bugzilla.gnome.org/show_bug.cgi?id=770026
These devices are kind of an strange case. Their "master" device is
the keyboard, because they share toplevel focus with it, regardless
of stylus focus. Nonetheless, they are only expected to send the
GdkEventPad* set of events.
https://bugzilla.gnome.org/show_bug.cgi?id=770026
This is a subclass of GdkWaylandDevice that implements GdkDevicePad,
all pad features are looked up from the info obtained through the
tablet v2 interface.
https://bugzilla.gnome.org/show_bug.cgi?id=770026
This GdkEventController is a helper object to handle pad events,
it allows setting a mapping to action names, to be triggered in
the given action group.
In order to help on places where advanced mapping/configurability
of pad features is not desirable, this controller also allows
passing a NULL pad device, meaning it will listen on all pads,
and/or passing -1 on mode/index, so an action applies to all
modes/features (eg. strips/rings).
https://bugzilla.gnome.org/show_bug.cgi?id=770026
This is an interface meant to be implemented by the "pad" devices.
This device-specific interface exposes the mapping of all pad features,
it allows retrieving:
- The number of buttons/rings/strips
- The number of groups
- The number of modes a group has
- Whether a given button/ring/strip belongs to a given group
https://bugzilla.gnome.org/show_bug.cgi?id=770026
We want the same treatment for those, the event will be emitted on the
toplevel, which will then decide what to do with the event.
It just doesn't make much sense to propagate those up/down the hierarchy,
when we want specifically one action being triggered from those.
https://bugzilla.gnome.org/show_bug.cgi?id=770026
GDK_PAD_BUTTON*,RING and STRIP will be emitted respectively when
pad buttons, rings or strips are interacted with. Each of those
pad components belong to a group (a pad can contain several of
those), which may be in a given mode. All this information is
contained in the event.
GDK_PAD_GROUP_MODE is emitted when a group in the pad switches
mode, which will generally result in a different set of actions
being triggered from the same buttons/rings/strips in the group.
https://bugzilla.gnome.org/show_bug.cgi?id=770026
