Summary:
There is no point in using quint32 and casting back and forth in numerous places.
Fix a bunch of compiler warnings that we implicitly cast between signed and unsigned.
This makes things consistent with what we get from libinput.
Reviewers: #kwin, romangg
Reviewed By: #kwin, romangg
Subscribers: zzag, romangg, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D23086
Summary:
This usage of QWeakPointer has been deprecated since Qt 5.0, since it
leads to really confusing API - usually you must never dereference a
QWeakPointer directly, but always go through QSharedPointer, except in
this one case, where it's permissible.
The thumbnails are only referenced in one place, this change is straight-forward.
Reviewers: #kwin, romangg
Reviewed By: #kwin, romangg
Subscribers: romangg, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D23070
Summary:
So far we were following a bit unique and rare doxygen comment style:
/**
* Contents of the comment.
**/
Doxygen comments with this style look balanced and neat, but many people
that contribute to KWin don't follow this style. Instead, they prefer
more traditional doxygen comment style, i.e.
/**
* Contents of the comment.
*/
Reviewing such changes has been a bit frustrating for me (so selfish!)
and for other contributors.
This change switches doxygen comment style in KWin to a more traditional
style. The main reason for doing this is to make code review process easier
for new contributors as well us.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D22812
Summary:
Currently code base of kwin can be viewed as two pieces. One is very
ancient, and the other one is more modern, which uses new C++ features.
The main problem with the ancient code is that it was written before
C++11 era. So, no override or final keywords, lambdas, etc.
Quite recently, KDE compiler settings were changed to show a warning if
a virtual method has missing override keyword. As you might have already
guessed, this fired back at us because of that ancient code. We had
about 500 new compiler warnings.
A "solution" was proposed to that problem - disable -Wno-suggest-override
and the other similar warning for clang. It's hard to call a solution
because those warnings are disabled not only for the old code, but also
for new. This is not what we want!
The main argument for not actually fixing the problem was that git
history will be screwed as well because of human factor. While good git
history is a very important thing, we should not go crazy about it and
block every change that somehow alters git history. git blame allows to
specify starting revision for a reason.
The other argument (human factor) can be easily solved by using tools
such as clang-tidy. clang-tidy is a clang-based linter for C++. It can
be used for various things, e.g. fixing coding style(e.g. add missing
braces to if statements, readability-braces-around-statements check),
or in our case add missing override keywords.
Test Plan: Compiles.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, apol, romangg, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D22371
Summary:
Window open/close animation effects should not animate the outline
because the end result is a bit awkward.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D19886
Summary:
We have a mix of different doxygen comment styles, e.g.
/*!
Foo bar.
*/
/**
* Foo bar.
*/
/** Foo bar.
*/
/**
* Foo bar.
*/
/**
* Foo bar.
**/
To make the code more consistent, this change updates the style of all
doxygen comments to the last one.
Test Plan: Compiles.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18683
Summary:
So far the ThumbnailItem in TabBox mode used the window id for finding
the window it should render a thumbnail on. In the Wayland world this is
not unique. The window id could be either an X11 window or a wayland
window. We don't guarantee that there are no conflicting ids.
With the internal id we have a way to properly identify the windows, so
this element should use them.
To support this the property changed the type to QUuid and the
clientmodel also provides the QUuid. As in TabBox the way to get the
window is through the model this should be compatible for all themes.
It's tested and verified with the Breeze switcher.
For declarative KWin scripts the ThumbnailItem also provides the
AbstractClient as a property, so there should not be any script which
uses wid. If it does, this could break, but well the script should use
the intended API.
Test Plan: ctest passes, manual testing of Breeze alt-tab switcher
Reviewers: #kwin
Differential Revision: https://phabricator.kde.org/D18405
Summary:
KWindowSystem provides a plugin interface to have platform specific
implementations. So far KWin relied on the implementation in
KWayland-integration repository.
This is something I find unsuited, for the following reasons:
* any test in KWin for functionality set through the plugin would fail
* it's not clear what's going on where
* in worst case some code could deadlock
* KWin shouldn't use KWindowSystem and only a small subset is allowed
to be used
The last point needs some further explanation. KWin internally does not
and cannot use KWindowSystem. KWindowSystem (especially KWindowInfo) is
exposing information which KWin sets. It's more than weird if KWin asks
KWindowSystem for the state of a window it set itself. On X11 it's just
slow, on Wayland it can result in roundtrips to KWin itself which is
dangerous.
But due to using Plasma components we have a few areas where we use
KWindowSystem. E.g. a Plasma::Dialog sets a window type, the slide in
direction, blur and background contrast. This we want to support and
need to support. Other API elements we do not want, like for examples
the available windows. KWin internal windows either have direct access
to KWin or a scripting interface exposed providing (limited) access -
there is just no need to have this in KWindowSystem.
To make it more clear what KWin supports as API of KWindowSystem for
internal windows this change implements a stripped down version of the
kwayland-integration plugin. The main difference is that it does not use
KWayland at all, but a QWindow internal side channel.
To support this EffectWindow provides an accessor for internalWindow and
the three already mentioned effects are adjusted to read from the
internal QWindow and it's dynamic properties.
This change is a first step for a further refactoring. I plan to split
the internal window out of ShellClient into a dedicated class. I think
there are nowadays too many special cases. If it moves out there is the
question whether we really want to use Wayland for the internal windows
or whether this is just historic ballast (after all we used to use
qwayland for that in the beginning).
As the change could introduce regressions I'm targetting 5.16.
Test Plan:
new test case for window type, manual testing using Alt+Tab
for the effects integration. Sliding popups, blur and contrast worked fine.
Reviewers: #kwin
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18228
Summary:
7834bec52a missed to port minimize and
unminimize to dynamic dispatch. In addition to that, we don't benefit
from QMetaObject::invokeMethod so port addRepaint and addLayerRepaint
to dynamic dispatch as well.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18049
Summary:
Some effects may release the current context when they tear down, so we
have to make the current context per each unloaded effect.
BUG: 396830
FIXED-IN: 5.15.0
Test Plan: No longer able to reproduce bug 396830.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D17716
Summary:
Compositing is suspended/finished in a very hard way fashion, effect
windows are destroyed without notifying effects about it.
AnimationEffect tries gracefully release deleted windows, but because
in some cases(like when suspending compositing) a deleted window can
be already destroyed, a segmentation fault can happen.
This change adjusts the order in which effect windows and effects are
destroyed, so AnimationEffect (and other effects) cannot access dangling
pointers.
BUG: 400788
FIXED-IN: 5.15.0
Reviewers: #kwin, graesslin
Reviewed By: #kwin, graesslin
Subscribers: graesslin, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D17311
Summary:
EffectWindow proxies its properties from the client/deleted's
properties.
QObject::property(char*) is a slow string search. It's a loop
of string comparisons not a hash lookup!
QML's use of properties is different, there's a property cache.
It's fetched multiple times for every window in every paint of some
effects (such as blur). Hotspot shows this as a significant amount of
the render pass (X11) with nothing in kwin animating.
This patch replaces the macro that does
parent()->property("propertyName")
with a macro calling the relevant function directly without metaobjects.
This also improves type safety for future changes.
Test Plan:
Existing unit tests
Ran it for a bit
Reviewers: #kwin, graesslin
Subscribers: graesslin, zzag, broulik, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D16602
Summary:
As setDesktop was changed to "move" this left unSetDesktop non-symetric.
This replaces it with explicit API to enter/leave.
This also moves new API to the new object based API rather than still
using ints.
Where numbers are used it has been tidied up so that desktop IDs are
uint, which should be used when we have a list of desktops.
int is used only when we have either a desktop ID or NET::OnAllDesktops
(-1)
Effects API cleared up to use this and use a set of x11 IDs, which
avoids any potential complications of handling add and removes any
ambiguity with what happens if you leave all desktops and such.
Test Plan:
testVirtualDesktops passes (with pending kwayland patch)
Moving a window in the desktop grid on X11 behaves
Moving a window in the desktop grid on wayland behaves
Reviewers: #kwin, zzag
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D16704
Summary:
Getter is exposed as a property on scripted effect in a way that hides
pointers from the scripting side.
Setter is implicitly handled as a property of newly created animations
and holds the activeFullScreenEffect whilst any of them are active. Like
existing effects it remains up to the effect author to avoid the
problems of multiple full screen effects. The RAII lock pattern is
somewhat overkill currently, but it's the direction I hope we can take
EffectsHandler in next API break.
BUG: 396790
--
This patch is against the QJSEngine port, though it's not conceptually a
requirement.
Test Plan: Unit test
Reviewers: #kwin, zzag
Reviewed By: #kwin, zzag
Subscribers: zzag, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D14688
Summary:
* effects.h includes client.h and forward declares Client, both at the
same time. Thus, delete the include;
* the blur effect includes effects.h. That, most likely, is a leftover
after 3f5bf65a9e.
Test Plan: Compiles.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D15191
Summary:
The Platform API is extended by a call to create the EffectsHandler. In
X11 standalone Platform a new EffectsHandlerImplX11 is added which
contains the X11 only parts of the EffectsHandler, such as grabbing the
X keyboard and the X11 mouse interception window.
The EffectsHandlerImpl gains some virtual methods for the parts which
are now done in the X11 specific implementation. In return we get rid of
lots of if-else structures checking for the operation mode.
Test Plan: Only compile tested.
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7955
Summary:
If an Effect has replaced the TabBox and wants to react on mouse events
the EffectsHandlerImpl also has an X11Filter, so we only need to make
sure the events go to that filter.
Motion: TabBox did not filter out, so events will go to the Effects
filter.
Press/Release: TabBox should not operate if Effects take the events.
The events are filtered out by Effects if there is a grab, so just
check for that and go out. Effects will take care.
Test Plan: Compiles
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7846
Summary:
So far both Workspace and Toplevel emitted signals for every property
notify event on the root window and the respective Toplevel windows. The
signals were only used in EffectsHandlerImpl to forward to the effect
system in case the property which changed is registered by an effect.
This change introduces a dedicated event filter for this which is only
created in EffectsHandlerImpl in case an X11 connection is available. It
supports a restart of the X11 system.
The signals used so far are removed from Workspace and Toplevel.
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7853
Summary:
This change introduces a dedicated X11EventFilter for the mouse
interception on X11. The filter gets created together with the start
of mouse interception and destroyed again when the mouse interception
ends. Thus we don't need to check for each event like it was the case
so far.
Unfortunately the existing methods cannot be removed (yet) as they are
still used by TabBox. Needs investigation whether this is actually
needed.
Test Plan: Xephyr+kwin_x11+Present Windows
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7842
Summary:
First step for loading the compositor Scenes through plugins. The general
idea is that we currently needlessly pull in all the Scenes although only
one will be used.
E.g. on X11 we pull in QPainter, although they are not compatible. On
Wayland we pull in XRender although they are not compatible.
Furthermore our current Scene creation strategy is not really fault
tolerant and can create situations where we don't get a compositor. E.g
on fbdev backend the default settings won't work as it does not support
OpenGL.
Long term I want to tackle those conceptional problems together:
we try to load all plugins supported by the current platform till we have
a scene which works. Thus on Wayland we don't end up in a situation where
we don't have a working compositor because the configuration is bad.
To make this possible the switch statement in the Scene needs to go and
needs to be replaced by a for loop iterating over all the available
scenes on the platform. If we go there it makes sense to replace it
directly with a plugin based approach.
So this is a change which tackles the problem by first introducing the
plugin loading. The xrender based scene (as it's the most simple one)
is moved into a plugin. It is first tried to find a scene plugin and only
if there is none the existing code is used.
Test Plan: Tested all scenes
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7232
Summary:
There are a few places where KWin needs to read values from kcminputrc.
As I need to add yet another one it makes more sense to properly
structure it like in other cases and have only one kcminputrc hold in
the application. This also allows to better mock the config values in
the integration tests.
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D5540
Summary:
By changing all kcfg to have arg="true" we can pass in the same
KSharedConfigPtr into all effects. This allows to have fake config in
the tests and in the planned effect demo mode.
Also it means that we don't have to hardcode the name kwinrc into the
files. In the configs - where we cannot access the effectshandler - we
use the define KWIN_CONFIG which gets generated based on the compile
time arguments.
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D3571
Summary:
This is implemented through QActions following the general approach
inside KWin and not the older approach used by ScreenEdges for pointer
callback activation.
Test Plan: Extended auto test
Reviewers: #kwin, #plasma
Subscribers: plasma-devel
Tags: #plasma
Differential Revision: https://phabricator.kde.org/D5263
Summary:
This change adds global touchpad swipe gestures to the
GlobalShortcutsManager and hooks up the swipe gestures as defined at the
Plasma Affenfels sprint:
* swipe up: Desktop Grid
* swipe down: Present Windows
* swipe left: previous virtual desktop
* swipe right: next virtual desktop
The main work is handled by two new classes: SwipeGesture and
GestureRecognizer. This is implemented in a way that it can be extended
to also recognize touch screen gestures and pinch gestures.
The SwipeGesture defines what is required for the gesture to trigger.
Currently this includes the minimum and maximum number of fingers
participating in the gesture and the direction. The gesture gets
registered in the GestureRecognizer.
The events for the gesture are fed into the GestureRecognizer. It
evaluates which gestures could trigger and tracks them for every update
of the gesture. In the process of the gesture tracking the
GestureRecognizer emits signals on the Gesture:
* started: when the Gesture gets considered for a sequence
* cancelled: the Gesture no longer matches the sequence
* triggered: the sequence ended and the Gesture still matches
The remaining changes are related to hook up the existing shortcut
framework with the new touchpad gestures. The GlobalShortcutManager
gained support for it, InputRedirection and EffectsHandler offer methods
to register a QAction. VirtualDesktopManager, PresentWindows and
DesktopGrid are adjusted to support the gesture.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel
Tags: #plasma_on_wayland
Differential Revision: https://phabricator.kde.org/D5097
Summary:
This change adds support for marking the OnScreenMessage as it should
skip close animation. The screenshot effect is adjusted to use the
on screen message instead of the custom effect frame.
Test Plan: Message window is not captured when taking screenshot
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D4091
Summary:
This adds support for the new on-screen-message support to the
kwineffects API and makes use of it in the colorpicker effect.
Not yet added to screenshot effect as for that we need support for
skip close animation on the on-screen-message window.
Reviewers: #plasma, #kwin
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D3803
Summary:
A second interactive selection mode gets added to select a position on
the screen. This is handled by the same input event filter as for the
window selection. Just that instead of returning a window, it returns a
QPoint.
This allows to pick a point on the screen which we need to screenshot
the screen under the mouse cursor and in future for color picking.
The screenshot effect provides two new dbus methods to (interactively)
select a screen or fullscreen. This allows spectacle to screenshot the
(full) screen with still having the user in control.
Reviewers: #kwin, #plasma_on_wayland, bgupta
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3475
Summary:
EffectsHandler gains a new method to startInteractiveWindowSelection
which just delegates to the one in Platform. That way a window can be
selected and returned to an Effect.
The screenshot effect makes use of this new functionality and provides
an interactive window screenshot mode which saves to a temporary file.
Note that this is not yet the variant intended for use in spectacle.
Test Plan: Took a screenshot on Wayland
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3367
Summary:
There is no effect using this method. As it's X11 specific it should be
removed.
Internally the EffectsHandlerImpl still requires the method. Thus it's
moved into the private part.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3297
Summary:
The method is not used by any Effect and is X11 specific, thus better
remove it for good.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3298
Summary:
The implementation delegates to the Platform to perform the actual
show/hide of the cursor image.
This replaces the implementation in the zoom effect which so far
directly interacted with xfixes to show/hide the cursor. This is now
provided by the x11/standalone platform. And due to this change the zoom
effect can now properly hide the cursor on platform DRM (wayland) as
well.
Test Plan: Zoom effect on Wayland hides the cursor
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3120
Summary:
There are several effects (screenshot, zoom) which need access to the
cursor image and cursor hotspot. So far these effects used X11
unconditionally to get the cursor which obviously does not work on
Wayland.
This change adds a new class PlatformCursorImage to kwinglobals which
wraps what a cursor is (image and hotspot) and adds a new virtual method
to Platform to provide such a PlatformCursorImage. By default it's the
cursor image the Platform tracks. On X11/standalone platform this new
virtual method is overriden and provides a PlatformCursorImage from X11
using the code previously used in screenshot effect.
Screenshot effect and zoom are adjusted to use the new API instead of
X11.
Test Plan:
Zoom effect tested on Wayland, now gets the proper cursor icon.
X11 functionality not yet tested.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3093
Summary:
So far TabBox used highlight windows by passing window ids around through
an X property. This doesn't work on Wayland where we don't have window
ids for our TabBox and the Wayland windows.
This change introduces a new Effect::Feature for HighlightWindows which
the HighlightWindowsEffect provides. The EffectsHandlerImpl has a new
method to highlightWindows which it delegates to that effect if it is
loaded by invoking a new performFeature method.
The TabBoxHandler now passes the highlighting to the effects system
instead of updating the x11 property. Thus this works on Wayland and
at the same time improves the X11 side by no longer having to go through
the property protocol.
Test Plan: Verified that Alt+Tab highlights the windows on Wayland correctly.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D2630
Summary:
The Effect class is extended by three new virtual methods:
* touchDown
* touchMotion
* touchUp
The methods return a boolean value so that the events can be filtered
out. E.g. an effect which has also a mouse grab installed wants to
filter out all events, other effects don't need the events exclusively.
This is a difference to how e.g. keyboard and pointer events are handled.
But is more close to how KWin's internal input event passing works and
makes it easier to get touch event: one does not explicitly has to grab
the events. It's also closer to Wayland where all input events are
available.
As a first example the Present Windows effect is adjusted and allows to
activate windows through the touch screen. As much code as possible is
shared with pointer input.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D2450
Summary:
A new method to tell the effects system whether the compositor scene
is able to drive animations. E.g. on software emulation (llvmpipe) it's
better to not do any animations at all.
This information can be used by effects to adjust their behavior, e.g.
PresentWindows could skip transitions or effects can use it in their
supported check to completely disable themselves.
As a first step all scripted effects are considered to be unsupported
if animations are not supported. They inherit AnimationEffect and are
all about driving animations.
The information whether animations are supported comes from the Scene.
It's implemented in the following way:
* XRender: animations are always supported
* QPainter: animations are never supported
* OpenGL: animations are supported, except for software emulation
In addition - for easier testing - there is a new env variable
KWIN_EFFECTS_FORCE_ANIMATIONS to overwrite the selection.
Reviewers: #kwin, #plasma
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D2386
It's created together with input, so that the input mechanismn already
has a way to check whether screen is locked.
Effects doesn't hold a member variable any more and instead uses the
singleton instance.
Being able to monitor whether the screen is locked is useful not only
to the effects system but overall in KWin. Thus to make it possible to
use it from more locations as a first step it's moved into dedicated
source files.
So far updating the cursor image was not really defined. It was possible
to use the cursor image from the wayland seat or have a custom set cursor
image. But there are no rules in place to decide which one to use when.
With this change a dedicated CursorImage class is introduced which tracks
the cursor image changes on the seat, on the decoration, in the effects
and so on. In addition it tracks which is the current source for the
image, that is whether e.g. the cursor from the seat or from effects
override should be used. Whenever the cursor image changes a signal is
emitted, which is connected to the signal in AbstractBackend.
Based on that the backends can directly show the image. The existing
code in the backends to install a cursor shape or to install the cursor
from the server is completely dropped. For the backend it's irrelevant
from where the image comes from.
A new feature added is that the cursor image is marked as rendered. This
is then passed on to the frame rendered in the Surface and thus animated
cursors are finally working. Unfortunately animated cursors are broken in
Qt (see https://bugreports.qt.io/browse/QTBUG-48181 ).
Some effects do X11 calls in their cleanup code through external
libraries (e.g. KSelectionOwner). As we cannot control that we need
to ensure the effects are unloaded prior to destroying the Xwayland
connection.
The signals operate on AbstractClient nowadays, so we can have one
implementation for both Client and ShellClient.
Only X specific connections are only done for Client.
The ShellClient is a Toplevel subclass for a
KWayland::Server::ShellSurfaceInterface. It gets created when a new
ShellSurfaceInterface is created and destoryed when it gets unmapped.
So far the usage is still rather limited. The ShellClient is opened
at position (0/0). While it's possible to pass pointer events to it,
it's not yet possible to activate it, so no keyboard focus.
