[RFC v2 wayland-protocols] tablet: define our own enum for tablet tool buttons

Ping Cheng pinglinux at gmail.com
Tue Nov 22 17:03:52 UTC 2016

On Tuesday, November 22, 2016, Daniel Stone <daniel at fooishbar.org> wrote:

> Hey,
> On 21 November 2016 at 23:13, Peter Hutterer <peter.hutterer at who-t.net
> <javascript:;>> wrote:
> > On Mon, Nov 21, 2016 at 12:42:36PM +0000, Daniel Stone wrote:
> >> Concretely though, reusing BTN_* codes where possible would make it
> >> easier for clients to transition between the two.
> >
> > I disagree here. The kernel only has BTN_STYLUS and BTN_STYLUS2, after
> that
> > we overlap with DOUBLETAP range and later buttons that are completely
> > different (e.g. BTN_GEAR_DOWN). I think this would only make it worse.
> > This protocol is still unstable, every client needs updates once we mark
> it
> > stable anyway, making the enums *values* mean something is
> counterproductive
> > IMO.
> Shrug, once in an enum they're totally arbitrary values (so which
> BTN_* they overlap doesn't make a difference), and it does make it a
> little harder to screw it up, as well as easier to stay compatible

I see pros and cons for both suggestions. I was into Peter's idea of
generic numbering since it is easier to implement and
offers some flexibility for client to decide how to translate those events.

However, I am kinda convinced by Daniel's point now. If the BTN_ has a
preferred default action/feature, kernel should report that information to
userland. Client should translate that default setting accordingly.

That's just my 2 cents. It's still your call, Peter ;-).


between multiple versions. But, your call.
> Cheers,
> Daniel
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