Introduce pointer locking and confinement protocol

This patch introduces a new protocol for locking and confining a
pointer. It consists of a new global object with two requests; one for
locking the surface to a position, one for confining the pointer to a
given region.

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Reviewed-by: Daniel Stone <daniels@collabora.com>

3 files changed, 349 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index 0389637..57d0023 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,6 +6,7 @@ unstable_protocols =								\
 	unstable/input-method/input-method-unstable-v1.xml			\
 	unstable/xdg-shell/xdg-shell-unstable-v5.xml				\
 	unstable/relative-pointer/relative-pointer-unstable-v1.xml		\
+	unstable/pointer-constraints/pointer-constraints-unstable-v1.xml	\
 	$(NULL)
 
 stable_protocols =								\
diff --git a/unstable/pointer-constraints/README b/unstable/pointer-constraints/README
new file mode 100644
index 0000000..8a242f8
--- /dev/null
+++ b/unstable/pointer-constraints/README
@@ -0,0 +1,4 @@
+Pointer constraints protocol
+
+Maintainers:
+Jonas Ådahl <jadahl@gmail.com>
diff --git a/unstable/pointer-constraints/pointer-constraints-unstable-v1.xml b/unstable/pointer-constraints/pointer-constraints-unstable-v1.xml
new file mode 100644
index 0000000..192622f
--- /dev/null
+++ b/unstable/pointer-constraints/pointer-constraints-unstable-v1.xml
@@ -0,0 +1,344 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="pointer_constraints_unstable_v1">
+
+  <copyright>
+    Copyright © 2014      Jonas Ådahl
+    Copyright © 2015      Red Hat Inc.
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice (including the next
+    paragraph) shall be included in all copies or substantial portions of the
+    Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+  </copyright>
+
+  <description summary="Protocol for constraining pointer motions">
+    This protocol specifies a set of interfaces used for adding constraints to
+    the motion of a pointer. Possible constraints include confining pointer
+    motions to a given region, or locking it to its current position.
+
+    In order to contrain the pointer, a client must first bind the global
+    interface "wp_pointer_constraints" which, if a compositor supports pointer
+    constraints, is exposed by the registry. Using the bound global object, the
+    client uses the request that corresponds to the type of constraint it wants
+    to make. See wp_pointer_constraints for more details.
+
+    Warning! The protocol described in this file is experimental and backward
+    incompatible changes may be made. Backward compatible changes may be added
+    together with the corresponding interface version bump.  Backward
+    incompatible changes are done by bumping the version number in the protocol
+    and interface names and resetting the interface version.  Once the protocol
+    is to be declared stable, the 'z' prefix and the version number in the
+    protocol and interface names are removed and the interface version number is
+    reset.
+  </description>
+
+  <interface name="zwp_pointer_constraints_v1" version="1">
+    <description summary="constrain the movement of a pointer">
+      The global interface exposing pointer constraining functionality. It
+      exposes two requests; lock_pointer for locking the pointer to its
+      position, and confine_pointer for locking the pointer to a region.
+
+      The lock_pointer and confine_pointer requests create the objects
+      wp_locked_pointer and wp_confined_pointer respectively, and the client can
+      use these objects to interact with the lock.
+
+      For any surface, only one lock or confinement may be active across all
+      wl_pointer objects of the same seat. If a lock or confinement is requested
+      when another lock or confinement is active or requested on the same surface
+      and with any of the wl_pointer objects of the same seat, an
+      'already_constrained' error will be raised.
+    </description>
+
+    <enum name="error">
+      <description summary="wp_pointer_constraints error values">
+	These errors can be emitted in response to wp_pointer_constraints
+	requests.
+      </description>
+      <entry name="already_constrained" value="1"
+	     summary="pointer constraint already requested on that surface"/>
+    </enum>
+
+    <enum name="lifetime">
+      <description summary="constraint lifetime">
+	These values represent different lifetime semantics. They are passed
+	as argument to the factory requests to specify how the constraint
+	lifetimes should be managed.
+      </description>
+      <entry name="oneshot" value="1">
+	<description summary="the pointer constraint is defunct once deactivated">
+	  A oneshot pointer constraint will never reactivate once it has been
+	  deactivated. See the corresponding deactivation event
+	  (wp_locked_pointer.unlocked and wp_confined_pointer.unconfined) for
+	  details.
+	</description>
+      </entry>
+      <entry name="persistent" value="2">
+	<description summary="the pointer constraint is may reactivate">
+	  A persistent pointer constraint may again reactivate once it has
+	  been deactivated. See the corresponding deactivation event
+	  (wp_locked_pointer.unlocked and wp_confined_pointer.unconfined) for
+	  details.
+	</description>
+      </entry>
+    </enum>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the pointer constraints manager object">
+	Used by the client to notify the server that it will no longer use this
+	pointer constraints object.
+      </description>
+    </request>
+
+    <request name="lock_pointer">
+      <description summary="lock pointer to a position">
+	The lock_pointer request lets the client request to disable movements of
+	the virtual pointer (i.e. the cursor), effectively locking the pointer
+	to a position. This request may not take effect immediately; in the
+	future, when the compositor deems implementation-specific constraints
+	are satisfied, the pointer lock will be activated and the compositor
+	sends a locked event.
+
+	The protocol provides no guarantee that the constraints are ever
+	satisfied, and does not require the compositor to send an error if the
+	constraints cannot ever be satisfied. It is thus possible to request a
+	lock that will never activate.
+
+	There may not be another pointer constraint of any kind requested or
+	active on the surface for any of the wl_pointer objects of the seat of
+	the passed pointer when requesting a lock. If there is, an error will be
+	raised. See general pointer lock documentation for more details.
+
+	The intersection of the region passed with this request and the input
+	region of the surface is used to determine where the pointer must be
+	in order for the lock to activate. It is up to the compositor whether to
+	warp the pointer or require some kind of user interaction for the lock
+	to activate. If the region is null the surface input region is used.
+
+	A surface may receive pointer focus without the lock being activated.
+
+	The request creates a new object wp_locked_pointer which is used to
+	interact with the lock as well as receive updates about its state. See
+	the the description of wp_locked_pointer for further information.
+
+	Note that while a pointer is locked, the wl_pointer objects of the
+	corresponding seat will not emit any wl_pointer.motion events, but
+	relative motion events will still be emitted via wp_relative_pointer
+	objects of the same seat. wl_pointer.axis and wl_pointer.button events
+	are unaffected.
+      </description>
+
+      <arg name="id" type="new_id" interface="zwp_locked_pointer_v1"/>
+      <arg name="surface" type="object" interface="wl_surface"
+	   summary="surface to lock pointer to"/>
+      <arg name="pointer" type="object" interface="wl_pointer"
+	   summary="the pointer that should be locked"/>
+      <arg name="region" type="object" interface="wl_region" allow-null="true"
+	   summary="region of surface"/>
+      <arg name="lifetime" type="uint" summary="lock lifetime"/>
+    </request>
+
+    <request name="confine_pointer">
+      <description summary="confine pointer to a region">
+	The confine_pointer request lets the client request to confine the
+	pointer cursor to a given region. This request may not take effect
+	immediately; in the future, when the compositor deems implementation-
+	specific constraints are satisfied, the pointer confinement will be
+	activated and the compositor sends a confined event.
+
+	The intersection of the region passed with this request and the input
+	region of the surface is used to determine where the pointer must be
+	in order for the confinement to activate. It is up to the compositor
+	whether to warp the pointer or require some kind of user interaction for
+	the confinement to activate. If the region is null the surface input
+	region is used.
+
+	The request will create a new object wp_confined_pointer which is used
+	to interact with the confinement as well as receive updates about its
+	state. See the the description of wp_confined_pointer for further
+	information.
+      </description>
+
+      <arg name="id" type="new_id" interface="zwp_confined_pointer_v1"/>
+      <arg name="surface" type="object" interface="wl_surface"
+	   summary="surface to lock pointer to"/>
+      <arg name="pointer" type="object" interface="wl_pointer"
+	   summary="the pointer that should be confined"/>
+      <arg name="region" type="object" interface="wl_region" allow-null="true"
+	   summary="region of surface"/>
+      <arg name="lifetime" type="uint" summary="confinement lifetime"/>
+    </request>
+  </interface>
+
+  <interface name="zwp_locked_pointer_v1" version="1">
+    <description summary="receive relative pointer motion events">
+      The wp_locked_pointer interface represents a locked pointer state.
+
+      While the lock of this object is active, the wl_pointer objects of the
+      associated seat will not emit any wl_pointer.motion events.
+
+      This object will send the event 'locked' when the lock is activated.
+      Whenever the lock is activated, it is guaranteed that the locked surface
+      will already have received pointer focus and that the pointer will be
+      within the region passed to the request creating this object.
+
+      To unlock the pointer, send the destroy request. This will also destroy
+      the wp_locked_pointer object.
+
+      If the compositor decides to unlock the pointer the unlocked event is
+      sent. See wp_locked_pointer.unlock for details.
+
+      When unlocking, the compositor may warp the cursor position to the set
+      cursor position hint. If it does, it will not result in any relative
+      motion events emitted via wp_relative_pointer.
+
+      If the surface the lock was requested on is destroyed and the lock is not
+      yet activated, the wp_locked_pointer object is now defunct and must be
+      destroyed.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the locked pointer object">
+	Destroy the locked pointer object. If applicable, the compositor will
+	unlock the pointer.
+      </description>
+    </request>
+
+    <request name="set_cursor_position_hint">
+      <description summary="set the pointer cursor position hint">
+	Set the cursor position hint relative to the top left corner of the
+	surface.
+
+	If the client is drawing its own cursor, it should update the position
+	hint to the position of its own cursor. A compositor may use this
+	information to warp the pointer upon unlock in order to avoid pointer
+	jumps.
+
+	The cursor position hint is double buffered. The new hint will only take
+	effect when the associated surface gets it pending state applied. See
+	wl_surface.commit for details.
+      </description>
+
+      <arg name="surface_x" type="fixed"
+	   summary="x coordinate in surface-relative coordinates"/>
+      <arg name="surface_y" type="fixed"
+	   summary="y coordinate in surface-relative coordinates"/>
+    </request>
+
+    <request name="set_region">
+      <description summary="set a new lock region">
+	Set a new region used to lock the pointer.
+
+	The new lock region is double-buffered. The new lock region will
+	only take effect when the associated surface gets its pending state
+	applied. See wl_surface.commit for details.
+
+	For details about the lock region, see wp_locked_pointer.
+      </description>
+
+      <arg name="region" type="object" interface="wl_region" allow-null="true"
+	   summary="region of surface"/>
+    </request>
+
+    <event name="locked">
+      <description summary="lock activation event">
+	Notification that the pointer lock of the seat's pointer is activated.
+      </description>
+    </event>
+
+    <event name="unlocked">
+      <description summary="lock deactivation event">
+	Notification that the pointer lock of the seat's pointer is no longer
+	active. If this is a oneshot pointer lock (see
+	wp_pointer_constraints.lifetime) this object is now defunct and should
+	be destroyed. If this is a persistent pointer lock (see
+	wp_pointer_constraints.lifetime) this pointer lock may again
+	reactivate in the future.
+      </description>
+    </event>
+  </interface>
+
+  <interface name="zwp_confined_pointer_v1" version="1">
+    <description summary="confined pointer object">
+      The wp_confined_pointer interface represents a confined pointer state.
+
+      This object will send the event 'confined' when the confinement is
+      activated. Whenever the confinement is activated, it is guaranteed that
+      the surface the pointer is confined to will already have received pointer
+      focus and that the pointer will be within the region passed to the request
+      creating this object. It is up to the compositor to decide whether this
+      requires some user interaction and if the pointer will warp to within the
+      passed region if outside.
+
+      To unconfine the pointer, send the destroy request. This will also destroy
+      the wp_confined_pointer object.
+
+      If the compositor decides to unconfine the pointer the unconfined event is
+      sent. The wp_confined_pointer object is at this point defunct and should
+      be destroyed.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the confined pointer object">
+	Destroy the confined pointer object. If applicable, the compositor will
+	unconfine the pointer.
+      </description>
+    </request>
+
+    <request name="set_region">
+      <description summary="set a new confine region">
+	Set a new region used to confine the pointer.
+
+	The new confine region is double-buffered. The new confine region will
+	only take effect when the associated surface gets its pending state
+	applied. See wl_surface.commit for details.
+
+	If the confinement is active when the new confinement region is applied
+	and the pointer ends up outside of newly applied region, the pointer may
+	warped to a position within the new confinement region. If warped, a
+	wl_pointer.motion event will be emitted, but no
+	wp_relative_pointer.relative_motion event.
+
+	The compositor may also, instead of using the new region, unconfine the
+	pointer.
+
+	For details about the confine region, see wp_confined_pointer.
+      </description>
+
+      <arg name="region" type="object" interface="wl_region" allow-null="true"
+	   summary="region of surface"/>
+    </request>
+
+    <event name="confined">
+      <description summary="pointer confined">
+	Notification that the pointer confinement of the seat's pointer is
+	activated.
+      </description>
+    </event>
+
+    <event name="unconfined">
+      <description summary="pointer unconfined">
+	Notification that the pointer confinement of the seat's pointer is no
+	longer active. If this is a oneshot pointer confinement (see
+	wp_pointer_constraints.lifetime) this object is now defunct and should
+	be destroyed. If this is a persistent pointer confinement (see
+	wp_pointer_constraints.lifetime) this pointer confinement may again
+	reactivate in the future.
+      </description>
+    </event>
+  </interface>
+
+</protocol>