[PATCH libinput 4/8] tablet: clarify tablet axis behavior in regards to proximity

[Peter Hutterer]

We send the axis state in the proximity event so we don't send another axis
event for the same state. The first axis event is sent whenever the tool
moves. This is largely of note for test cases, in real-world usage a tool
cannot be held still enough to never send axis updates.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/libinput.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/libinput.h b/src/libinput.h
index 018dbd4..c5f9da7 100644
--- a/src/libinput.h
+++ b/src/libinput.h
@@ -267,6 +267,13 @@ enum libinput_event_type {
 	 * LIBINPUT_DEVICE_CAP_TABLET capability. This event is only sent
 	 * when the tool is in proximity, see @ref
 	 * LIBINPUT_EVENT_TABLET_PROXIMITY for details.
+	 *
+	 * The proximity event contains the initial state of the axis as the
+	 * tool comes into proximity. An event of type @ref
+	 * LIBINPUT_EVENT_TABLET_AXIS is only sent when an axis value
+	 * changes from this initial state. It is possible for a tool to
+	 * enter and leave proximity without sending an event of type @ref
+	 * LIBINPUT_EVENT_TABLET_AXIS.
 	 */
 	LIBINPUT_EVENT_TABLET_AXIS = 600,
 	/**
-- 
2.4.3