[PATCH weston v3 1/5] protocol: Add _wl_pointer_gestures (swipe/pinch) protocol

[Carlos Garnacho]

The whole feature is exposed by the wl_pointer_gestures global
resource, which can be used to obtain individual swipe/pinch
gesture interfaces for a given wl_pointer.

The lifetime and progress of gestures is maintained by the separate
wl_pointer_gesture_pinch and wl_pointer_gesture_swipe interfaces,
each of these has begin/update(optional)/end phases, as transmitted
by their events.

The protocol is marked as unstable, an is thus '_' prefixed, this
prefix will be removed when the protocol is deemed stable.

v3: Reword exclusiveness of gestures and client-side semantics.
    specify further the "cancelled" field in end events. Renamed
    XML file to be more specific.
v2: Moved to an standalone xml

Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
Reviewed-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 Makefile.am                   |   3 +
 protocol/pointer-gestures.xml | 172 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 175 insertions(+)
 create mode 100644 protocol/pointer-gestures.xml

diff --git a/Makefile.am b/Makefile.am
index 76ab546..6334865 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -96,6 +96,8 @@ weston_SOURCES =					\
 	src/weston-egl-ext.h
 
 nodist_weston_SOURCES =					\
+	protocol/pointer-gestures-protocol.c		\
+	protocol/pointer-gestures-server-protocol.h	\
 	protocol/screenshooter-protocol.c		\
 	protocol/screenshooter-server-protocol.h	\
 	protocol/text-cursor-position-protocol.c	\
@@ -1298,6 +1300,7 @@ BUILT_SOURCES +=				\
 	protocol/text-client-protocol.h
 
 EXTRA_DIST +=					\
+	protocol/pointer-gestures.xml		\
 	protocol/desktop-shell.xml		\
 	protocol/screenshooter.xml		\
 	protocol/text.xml			\
diff --git a/protocol/pointer-gestures.xml b/protocol/pointer-gestures.xml
new file mode 100644
index 0000000..1bca8f7
--- /dev/null
+++ b/protocol/pointer-gestures.xml
@@ -0,0 +1,172 @@
+<protocol name="pointer_gestures">
+  <interface name="_wl_pointer_gestures" version="1">
+    <description summary="touchpad gestures">
+      A global interface to provide semantic touchpad gestures for a given
+      pointer.
+
+      Two gestures are currently supported: swipe and zoom/rotate.
+      All gestures follow a three-stage cycle: begin, update, end and
+      are identified by a unique id.
+
+      Warning! The protocol described in this file is experimental. Each
+      version of this protocol should be considered incompatible with any
+      other version, and a client binding to a version different to the one
+      advertised will be terminated. Once the protocol is declared stable,
+      compatibility is guaranteed, the '_' prefix will be removed from the
+      name and the version will be reset to 1.
+    </description>
+
+    <request name="get_swipe_gesture">
+      <description summary="get swipe gesture">
+	Create a swipe gesture object. See the
+	wl_pointer_gesture_swipe interface for details.
+      </description>
+      <arg name="id" type="new_id" interface="_wl_pointer_gesture_swipe"/>
+      <arg name="pointer" type="object" interface="wl_pointer"/>
+    </request>
+
+    <request name="get_pinch_gesture">
+      <description summary="get pinch gesture">
+	Create a pinch gesture object. See the
+	wl_pointer_gesture_pinch interface for details.
+      </description>
+      <arg name="id" type="new_id" interface="_wl_pointer_gesture_pinch"/>
+      <arg name="pointer" type="object" interface="wl_pointer"/>
+    </request>
+  </interface>
+
+  <interface name="_wl_pointer_gesture_swipe" version="1">
+    <description summary="a swipe gesture object">
+      A swipe gesture object notifies a client about a multi-finger swipe
+      gesture detected on an indirect input device such as a touchpad.
+      The gesture is usually initiated by multiple fingers moving in the
+      same direction but once initiated the direction may change.
+      The precise conditions of when such a gesture is detected are
+      implementation-dependent.
+
+      A gesture consists of three stages: begin, update (optional) and end.
+      There cannot be multiple simultaneous pinch or swipe gestures on a
+      same pointer/seat, how compositors prevent these situations is
+      implementation-dependent.
+
+      A gesture may be cancelled by the compositor or the hardware.
+      Clients should not consider performing permanent or irreversible
+      actions until the end of a gesture has been received.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the pointer swipe gesture object"/>
+    </request>
+
+    <event name="begin">
+      <description summary="multi-finger swipe begin">
+	This event is sent when a multi-finger swipe gesture is detected
+	on the device.
+      </description>
+      <arg name="serial" type="uint"/>
+      <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
+      <arg name="surface" type="object" interface="wl_surface"/>
+      <arg name="fingers" type="uint" summary="number of fingers"/>
+    </event>
+
+    <event name="update">
+      <description summary="multi-finger swipe motion">
+	This event is sent when a multi-finger swipe gesture changes the
+	position of the logical center.
+
+	The dx and dy coordinates are relative coordinates of the logical
+	center of the gesture compared to the previous event.
+      </description>
+      <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
+      <arg name="dx" type="fixed" summary="delta x coordinate in surface coordinate space"/>
+      <arg name="dy" type="fixed" summary="delta y coordinate in surface coordinate space"/>
+    </event>
+
+    <event name="end">
+      <description summary="multi-finger swipe end">
+	This event is sent when a multi-finger swipe gesture ceases to
+	be valid. This may happen when one or more finger is lifted or
+	the gesture is cancelled.
+
+	When a gesture is cancelled, the client should undo state changes
+	caused by this gesture. What causes a gesture to be cancelled is
+	implementation-dependent.
+      </description>
+      <arg name="serial" type="uint"/>
+      <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
+      <arg name="cancelled" type="int" summary="1 if the gesture was cancelled, 0 otherwise"/>
+    </event>
+  </interface>
+
+  <interface name="_wl_pointer_gesture_pinch" version="1">
+    <description summary="a pinch gesture object">
+      A pinch gesture object notifies a client about a multi-finger pinch
+      gesture detected on an indirect input device such as a touchpad.
+      The gesture is usually initiated by multiple fingers moving towards
+      each other or away from each other, or by two or more fingers rotating
+      around a logical center of gravity.  The precise conditions of when
+      such a gesture is detected are implementation-dependent.
+
+      A gesture consists of three stages: begin, update (optional) and end.
+      There cannot be multiple simultaneous pinch or swipe gestures on a
+      same pointer/seat, how compositors prevent these situations is
+      implementation-dependent.
+
+      A gesture may be cancelled by the compositor or the hardware.
+      Clients should not consider performing permanent or irreversible
+      actions until the end of a gesture has been received.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the pinch gesture object"/>
+    </request>
+
+    <event name="begin">
+      <description summary="multi-finger pinch begin">
+	This event is sent when a multi-finger pinch gesture is detected
+	on the device.
+      </description>
+      <arg name="serial" type="uint"/>
+      <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
+      <arg name="surface" type="object" interface="wl_surface"/>
+      <arg name="fingers" type="uint" summary="number of fingers"/>
+    </event>
+
+    <event name="update">
+      <description summary="multi-finger pinch motion">
+	This event is sent when a multi-finger pinch gesture changes the
+	position of the logical center, the rotation or the relative scale.
+
+	The dx and dy coordinates are relative coordinates in the
+	surface coordinate space of the logical center of the gesture.
+
+	The scale factor is an absolute scale compared to the
+	pointer_gesture_pinch.begin event, e.g. a scale of 2 means the fingers
+	are now twice as far apart as on pointer_gesture_pinch.begin.
+
+	The rotation is the relative angle in degrees clockwise compared to the previous
+	pointer_gesture_pinch.begin or pointer_gesture_pinch.update event.
+      </description>
+      <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
+      <arg name="dx" type="fixed" summary="delta x coordinate in surface coordinate space"/>
+      <arg name="dy" type="fixed" summary="delta y coordinate in surface coordinate space"/>
+      <arg name="scale" type="fixed" summary="scale relative to the initial finger position"/>
+      <arg name="rotation" type="fixed" summary="angle in degrees cw relative to the previous event"/>
+    </event>
+
+    <event name="end">
+      <description summary="multi-finger pinch end">
+	This event is sent when a multi-finger pinch gesture ceases to
+	be valid. This may happen when one or more finger is lifted or
+	the gesture is cancelled.
+
+	When a gesture is cancelled, the client should undo state changes
+	caused by this gesture. What causes a gesture to be cancelled is
+	implementation-dependent.
+      </description>
+      <arg name="serial" type="uint"/>
+      <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
+      <arg name="cancelled" type="int" summary="1 if the gesture was cancelled, 0 otherwise"/>
+    </event>
+  </interface>
+</protocol>
-- 
2.4.3