Many effects use the stacking order property of the effects handler in
their constructors. This means that windows should have compositing
setup by the time effects are loaded.
After changing how binary effect plugins are loaded, i.e. not queueing
loading effects, but loading them immediately, some effects broke
because the effects handler is created before windows setup compositing.
This change attempts to fix those effects by rearranging compositor
startup code so windows setup compositing first, then create the effects
pointer.
The Compositor contains nothing that can potentially get dirty and need
repainting.
As is, the advantages of this move aren't really noticeable, but it
makes sense with multiple scenes.
Backend parts are far from ideal, they can be improved later on as we
progress with the scene redesign.
The main idea behind the render backend is to decouple low level bits
from scenes. The end goal is to make the render backend provide render
targets where the scene can render.
Design-wise, such a split is more flexible than the current state, for
example we could start experimenting with using qtquick (assuming that
the legacy scene is properly encapsulated) or creating multiple scenes,
for example for each output layer, etc.
So far, the RenderBackend class only contains one getter, more stuff will
be moved from the Scene as it makes sense.
The GlStrictBinding flag indicates whether it's okay not to re-bind the X11
pixmap to the OpenGL surface texture if the corresponding window is damaged.
It doesn't really affect the SceneOpenGL, only low level backend stuff.
Currently, the scene owns the renderer, which puts more
responsibilities on the scene other than painting windows and it also
puts some limitations on what we can do, for example, there can be only
one scene, etc.
This change decouples the scene and the renderer so the scene is more
swappable.
Scenes are no longer implemented as plugins because opengl backend
and scene creation needs to be wrapped in opengl safety points. We
could still create the render backend and then go through the list
of scene plugins, but accessing concrete scene implementation is
much much simpler. Besides that, having scenes implemented as plugins
is not worthwhile because there are only two scenes and each contributes
very small amount of binary size. On the other hand, we still need to
take into account how many times kwin accesses the hard drive to load
plugins in order to function as expected.
Before attempting to create scenes, kwin will redirect windows but if
the opengl scene can't be created, it won't unredirect windows, which
seems to cause issues on aarch64.
BUG: 443953
This makes the compositingPossible() output more elaborative,
and adjusts their priorities to qCWarning.
I thought about dropping the "Compositing is not possible"
(qCCritical) message. It's not critical for X11 and Wayland
depends on OpenGL. OTOH it's from a different component. So in
the end I settled for qCWarning again; there is no real way
to know, if the platform will consider this a critical problem
(and eventually abort).
Then I saw X11StandalonePlatform::compositingNotPossibleReason,
which has more user friendly, QT Richtext / HTML encoded output,
but this seems overkill for the terminal; now I would like to
know, where this is actually used...
While at it report "manually" suspended compositing via qCInfo
instead of qCDebug.
It's confusing to have two signals (virtualScreenGeometryChanged() and
screenGeometryChanged()) that indicate the same thing.
This change ports parts of kwin from the screenGeometryChanged() signal
to the virtualScreenGeometryChanged() signal with the main motivation to
drop the former.
The virtualScreenGeometryChanged() signal was chosen as the replacement
for the consistency sake with EffectsHandler's virtualScreenGeometry and
virtualScreenSize properties.
When the aboutToDestroy signal is emitted, the compositor object is
already partially destroyed. This contradicts to the name of the signal.
In addition to that, it will be better to call the stop method in the
destructors of X11Compositor and WaylandClient as it allows them to add
custom cleanup code when compositing is turned off.
The Xrender backend was added at the time when OpenGL drivers were not
particularly stable. Nowadays though, it's a totally different situation.
The OpenGL render backend has been the default one for many years. It's
quite stable, and it allows implementing many advanced features that
other render backends don't.
Many features are not tested with it during the development cycle; the
only time when it is noticed is when changes in other parts of kwin break
the build in the xrender backend. Effectively, the xrender backend is
unmaintained nowadays.
Given that the xrender backend is effectively unmaintained and our focus
being shifted towards wayland, this change drops the xrender backend in
favor of the opengl backend.
Besides being de-facto unmaintained, another issue is that QtQuick does
not support and most likely will never support the Xrender API. This
poses a problem as we want thumbnail items to be natively integrated in
the qtquick scene graph.
Currently, dealing with sub-surfaces is very difficult due to the scene
design being heavily influenced by X11 requirements.
The goal of this change is to re-work scene abstractions to make improving
the wayland support easier.
The Item class is based on the QQuickItem class. My hope is that one day
we will be able to transition to QtQuick for painting scene, but in
meanwhile it makes more sense to have a minimalistic internal item class.
The WindowItem class represents a window. The SurfaceItem class represents
the contents of either an X11, or a Wayland, or an internal surface. The
DecorationItem and the ShadowItem class represent the server-side deco and
drop-shadow, respectively.
At the moment, the SurfaceItem is bound to the scene window, but the long
term plan is to break that connection so we could re-use the SurfaceItem
for things such as software cursors and drag-and-drop additional icons.
One of the responsibilities of the Item is to schedule repaints as needed.
Ideally, there shouldn't be any addRepaint() calls in the core code. The
Item class schedules repaints on geometry updates. In the future, it also
has to request an update if its opacity or visibility changes.
Once in a while, we receive complaints from other fellow KDE developers
about the file organization of kwin. This change addresses some of those
complaints by moving all of source code in a separate directory, src/,
thus making the project structure more traditional. Things such as tests
are kept in their own toplevel directories.
This change may wreak havoc on merge requests that add new files to kwin,
but if a patch modifies an already existing file, git should be smart
enough to figure out that the file has been relocated.
We may potentially split the src/ directory further to make navigating
the source code easier, but hopefully this is good enough already.
