The Compositor class actually behaves like a Singleton so it should be
one. Therefore four static methods are added:
* self() to access the Singleton
* createCompositor() to be used by Workspace to create the instance
* isCreated() to have a simple check whether the Singleton is already
created
* compositing() as a shortcut to test whether the compositor has been
created and is active
The isCreated() check is actually required as especially Clients might
be created and trying to access the Compositor before it is setup.
It seems not all Qt installs will automatically #include QElapsedTimer
from QtCore/QTimer, this caused a build failure on my system and on a
RHEL 6.2 VM I've been testing on.
Checking the Qt docs, QBasicTimer also has a separate include so
although this didn't cause a build failure, I've thrown in its
separate #include as well. I have not checked for other #include errors,
and a very quick search on b.k.o for bugs mentioning "build" did not
return any bugs to close.
I'm pretty sure this build failure applies only to master but I haven't
checked thoroughly.
For most actions where the compositor needs to perform an action
(e.g. scheduling another repaint) signals were already emitted.
So it's easier to just connect the signals to the Compositor
which in turn makes the code much more readable.
All signals are connected from the Workspace when either the
Compositor gets constructed or a Toplevel gets created.
The DBus signal which causes KWin to reinitialize the Compositor
is moved into the Compositor as everything can be handled from
there as well. This comes together with moving the restartKWin
functionality into the Compositor as it is only relevant there.
Restart will only happen if the wrong Qt graphicssystem is used
for the chosen compositing backend.
All the custom slot did was printing a debug statement and
calling finish. We do not need this debug statement. The times
of Compositors not part of Window Managers are over, so it is
extremely unlikely that we lose the ownership without KWin
going down anyway.
The Scene has always been created and destroyed inside what is
now the split out compositor. Which means it is actually owned
by the Compositor. The static pointer has never been needed
inside KWin core. Access to the Scene is not required for the
Window Manager. The only real usage is in the EffectsHandlerImpl
and in utils.h to provide a convenient way to figure out whether
compositing is currently active (scene != NULL).
The EffectsHandlerImpl gets also created by the Compositor after
the Scene is created and gets deleted just before the Scene gets
deleted. This allows to inject the Scene into the EffectsHandlerImpl
to resolve the static access in this class.
The convenient way to access the compositing() in utils.h had
to go. To provide the same feature the Compositor provides a
hasScene() access which has the same behavior as the old method.
In order to keep the code changes small in Workspace and Toplevel
a new method compositing() is defined which properly resolves
the state. A disadvantage is that this can no longer be inlined
and consists of several method calls and pointer checks.
Replaces the member variable which is actually not needed as a
pointer to the Workspace can always be retrieved through the
singleton accessor of Workspace.
All Workspace functions which were implemented in the file composite.cpp
were moved to an own class Compositor. The header entries were moved as well.
All functions calls are updated.
