[RFE wayland] protocol: add axis_source.wheel_tilt

[Peter Hutterer]

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
This is missing the various version bumps, it's just an RFE at this point.
We have a bit of a problem with the axis sources in the wayland protocol in
that they're sent but not really explained well in the protocol.

So to match the rest we pretty much just need to add tilt. And then maybe
define the other axis sources more verbosely. Hindsight and whatnot.

 protocol/wayland.xml | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/protocol/wayland.xml b/protocol/wayland.xml
index 098f286..0735997 100644
--- a/protocol/wayland.xml
+++ b/protocol/wayland.xml
@@ -1986,10 +1986,15 @@
 	finger. One example for this source is button-based scrolling where
 	the vertical motion of a device is converted to scroll events while
 	a button is held down.
+
+	The "wheel tilt" axis source indicates that the actual device is a
+	wheel but the scroll event is not caused by a rotation but a
+	(usually sideways) tilt of the wheel.
       </description>
-      <entry name="wheel" value="0" summary="a physical wheel" />
+      <entry name="wheel" value="0" summary="a physical wheel rotation" />
       <entry name="finger" value="1" summary="finger on a touch surface" />
       <entry name="continuous" value="2" summary="continuous coordinate space"/>
+      <entry name="wheel_tilt" value="3" summary="a physical wheel tilt"/>
     </enum>
 
     <event name="axis_source" since="5">
@@ -2004,7 +2009,8 @@
 	wl_pointer.axis_source.finger, a wl_pointer.axis_stop event will be
 	sent when the user lifts the finger off the device.
 
-	If the source is wl_pointer axis_source.wheel or
+	If the source is wl_pointer.axis_source.wheel,
+	wl_pointer.axis_source.wheel_tilt or
 	wl_pointer.axis_source.continuous, a wl_pointer.axis_stop event may
 	or may not be sent. Whether a compositor sends an axis_stop event
 	for these sources is hardware-specific and implementation-dependent;
-- 
2.9.3