input: add tablet stylus button triggers and binds

[youssefadly237]

Add support for tablet stylus button bindings

Example

binds {
    Super+TabletStylusPrimary { spawn-sh "some-script.sh"; } 
    TabletStylusSecondary { toggle-overview; }
}

Notes

I did test with Wacom CTL-472, but it should work on all tablets

Button codes are BTN_STYLUS, BTN_STYLUS2 include/uapi/linux/input-event-codes.h lines 414-L415 as of 4bdb6a1659873dfc625ded30a68cb387e328f34e

[YaLTeR]

Here are some comments. Maybe there's a chance this can make it into the release. :)

Thanks for the link to linux uapi include btw, that was helpful to double-check.

[youssefadly237]

could be relevant but I don't have the hardware to test it

Pad keys (Wacom M Pad)

Physical key	Code (int)	Code (hex)	Name
Key 0	256	0x100	BTN_0
Key 1	257	0x101	BTN_1
Key 2	258	0x102	BTN_2
Key 3	259	0x103	BTN_3
Key 4	260	0x104	BTN_4
Key 5	261	0x105	BTN_5
Key 6	262	0x106	BTN_6
Key 7	263	0x107	BTN_7
Key 8 (ring center)	264	0x108	BTN_8

upper column is 0,1,2,3
bottom column is 4,5,6,7
ring center is 8

there is a touch ring around the center button is ABS_WHEEL I guess

pad buttons are almost standerd for wacom devices but it varies, some other companies just send keyboard or mouse events instead, drivers/hid/wacom_wac.c

[UnskilledWolf]

I just tested this on my Wacom Intuos Pro (PTH-451) and both stylus button bindings work as expected. My tablet also does only have two buttons on the stylus, so I was not able to try TabletStylusButton3.

I also tried implementing bindings for the other keys on the tablet, based on the key codes above. However, I could not get these to trigger. I am not very familiar with rust, so I may have missed something. My attempt is published as a fork of this PR's branch in case anyone would like to take a look.

[youssefadly237]

yeah I checked your fork, I don't think this is the way to implement it, because you are treating the pad buttons as if they were stylus buttons, after reconsidering, I guess this is out of the scope of this pr, I don't have a tablet with pad buttons to test it, but I will try to implement it and message you on element x for testing?

[youssefadly237]

pad button support is not yet implemented in Smithay

Related:

• feat: expose TabletPadButton as a trigger for using commands #2536
• tablet: Add tablet pads implementation Smithay/smithay#1955
• feat: implement TabletPadButtonEvent support Smithay/smithay#1836