EffectsHandlerImpl::isEffectsSupported performs the check whether the
effect with the given name is supported by the current compositor.
The check is the following:
* if effect is already loaded, it is supported
* if the effect cannot be found, it is not supported
* if it's a scripted effect, it's always supported
* if it's a built-in effect, we ask BuiltInEffects::supported
* for all other effects we resolve the library and the supported
method
The idea behind providing this functionality in the DBus interface is
to allow filtering in the effects KCM for the effects which are
supported by the current compositor.
In addition a areEffectsSupported method is added which takes a
list of names and returns a list of bools.
REVIEW: 116665
Two new interfaces are introduced:
* org.kde.kwin.Compositing
* org.kde.kwin.Effects
The Compositing interface is generated from scriptable elements on the
KWin::Compositor class and the Compositor is exported as /Compositor.
It provides the general Compositing related D-Bus methods like whether
the compositor is active and toggling and so on.
The Effects interface is generated from scriptable elements on the
KWin::EffectsHandlerImpl class and the instance is exported as /Effects.
It provides all the effects related D-Bus methods like loading an effect
or the list of all effects.
This removes the need to have all these methods provided on the global
org.kde.KWin interface. For backwards compatibility they are kept, but
no longer provided by the Workspace class. Instead a new DBusInterface
is generated which wrapps the calls and delegates it to one of our three
related Singleton objects:
* Workspace
* Compositor
* EffectsHandlerImpl
