[PATCH wayland-protocols 2/2] Introduce pointer locking and confinement protocol

Peter Hutterer peter.hutterer at who-t.net
Wed Nov 18 16:59:05 PST 2015


On Tue, Nov 17, 2015 at 06:09:18PM +0800, Jonas Ådahl wrote:
> 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 at gmail.com>
> ---
> 
> Changes since last version sent as weston patches:
> 
> Interfaces and protocol renamed according to wayland-protocols naming
> conventions.
> 
> The global interface is now called wl_pointer_constraints instead of
> wl_pointer_lock.
> 
> The position hint is now double buffered.
> 
> Various other minor changes.
> 
> 
> Jonas
> 
> 
>  Makefile.am                                        |   1 +
>  unstable/pointer-constraints/README                |   4 +
>  .../pointer-constraints-unstable-v1.xml            | 283 +++++++++++++++++++++
>  3 files changed, 288 insertions(+)
>  create mode 100644 unstable/pointer-constraints/README
>  create mode 100644 unstable/pointer-constraints/pointer-constraints-unstable-v1.xml
> 
> diff --git a/Makefile.am b/Makefile.am
> index 2db6bd5..983ae1b 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -6,6 +6,7 @@ nobase_dist_pkgdata_DATA =							\
>  	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)
>  
>  pkgconfigdir = $(libdir)/pkgconfig
> 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 at 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..c71d6d5
> --- /dev/null
> +++ b/unstable/pointer-constraints/pointer-constraints-unstable-v1.xml
> @@ -0,0 +1,283 @@
> +<?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>
> +
> +  <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 creates the objects wp_locked_pointer

typo: create
and either skip "The" or use "The ... requests"

> +      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 per seat may be active at
> +      any time. If a lock or confinement is requested when another lock or
> +      confinement is active or requested on that surface and seat, an
> +      'already_constrained' error will be raised.
> +
> +      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>
> +
> +    <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 aleady requested on that surface"/>
> +    </enum>
> +
> +    <request name="lock_pointer">
> +      <description summary="lock pointer to a position">
> +	The lock_pointer request lets the client disable absolute pointer
> +	movements, locking the pointer to a position. 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.

typo: implementation-specific

wording: "absolute pointer movements" is ambiguous since we disable both
relative and absolute movements, only wl_relative_pointer isn't affected.
How about:
"...disables movements of the virtual pointer (i.e. the cursor),
effectively locking the pointer to a position."

followed by a "This request may not take effect immediately. Int the
future..."

> +
> +	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 lock of any kind requested or active on the
> +	surface for the seat when requesting a lock, and if there is, an error

s/, and if/. If/

> +	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 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.

"whether to warp the pointer or require..."

> +
> +	A surface may receive pointer focus without the lock being activated.
> +
> +	The request will create 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 motion events, but relative motion

I would explicitly state wl_pointer.motion events here, to avoid any
potential ambiguity. And add that axis and button events are unaffected.

> +	events will still be emitted via wp_relative_pointer objects of the
> +	same seat.
> +      </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="seat" type="object" interface="wl_seat"
> +	   summary="seat where the pointer should be locked"/>
> +      <arg name="region" type="object" interface="wl_region" allow-null="true"
> +	   summary="region of surface"/>
> +    </request>
> +
> +    <request name="confine_pointer">
> +      <description summary="confine pointer to a region">
> +	The confine_pointer request lets the client confine the pointer cursor
> +	to a given region.

add the same blurb with "no immediate effect, in the future, blah"

> +
> +	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 to
> +	warp the pointer, or require some kind of user interaction for the

"whether to warp the pointer or require some..."


> +	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="seat" type="object" interface="wl_seat"
> +	   summary="seat where the pointer should be locked"/>
> +      <arg name="region" type="object" interface="wl_region" allow-null="true"
> +	   summary="region of surface"/>
> +    </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 motion events.

wl_pointer.motion

> +
> +      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. The wp_locked_pointer object is at this point defunct and should be
> +      destroyed.
> +
> +      When unlocking, the compositor may take the cursor position pointer. If

s/pointer pointer/pointer hint/

> +      it does, it will not result in any relative motion events emitted via
> +      wp_relative_pointer.
> +
> +      If the surface lock was requested on is destroyed and the lock is not yet

"the lock was requested on"

> +      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. The compositor will unlock the
> +	pointer.

"If applicable, the compositor will..."

> +      </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.
> +
> +	The new region has no effect on a lock that has already been activated.
> +
> +	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 this seat's pointer is activated.
> +      </description>
> +    </event>
> +
> +    <event name="unlocked">
> +      <description summary="lock deactivation event">
> +	Notification that the pointer lock of seat's pointer is no longer
> +	active. This object is now defunct and should be destroyed.
> +      </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. The compositor will unconfine the
> +	pointer.

"If applicable, ..."

All these are typos only, the protocol looks good
Reviewed-by: Peter Hutterer <peter.hutterer at who-t.net>

Cheers,
   Peter

> +      </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 is
> +	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.
> +
> +	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="enter event">
> +	Notification that the pointer confinement of this seat's pointer is
> +	activated.
> +      </description>
> +    </event>
> +
> +    <event name="unconfined">
> +      <description summary="leave event">
> +	Notification that the pointer confinement of seat's pointer is no
> +	longer active. This object is no defunct and should be destroyed.
> +      </description>
> +    </event>
> +  </interface>
> +
> +</protocol>
> -- 
> 2.4.3


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