These are styli like the Dell Active Pen and most of the styli supplied
with laptops with built-in tablets. We don't always know how many
buttons these have so the SVG has just one large button. They're
typicall slimmer and less rounded than the Wacom pens so let's reflect
this here too.
This requires libwacom 1.4 released June 2020
If you did not know the Wacom Express Key Remote (or EKR for short),
let me introduce it to you:
https://estore.wacom.com/media/catalog/product/cache/fb4143a007ae6439deba9b18afd745f2/a/c/ack-411050_main_2.jpg
This is a hand-sized standalone pad device, meant to be used together
with drawing tablets, providing additional buttons and a touch sensitive
ring that can be mapped to actions and keypresses.
These pads were so far handled in GNOME, but in a very subtle manner.
As the EKR is implicitly paired to a tablet, it was possible to map
EKR buttons from the paired tablet once the pad OSD UI from GNOME
Shell was shown.
As this device basically just needs a "Map buttons" action to
configure it, it just didn't sit well in the older Settings UI,
it would get a separate page with just a lone button in there. So
its support has been kind of an easter egg so far.
But the new UI can indeed accomodate better a device that is neither
tablet nor stylus, and has few options. This commit adds the EKR
as a separate AdwPreferencesGroup.
Same dog, different collar. The UI has been ported 1:1 to GTK+, using
GtkBuilder, CSS and event controllers fairly reduced the amount of code
needed for this.
It also allows us to stop initializing clutter-gtk across the several
executables.
