Each effect is able to declare itself as currently being active,
that is transforming windows or painting or screen or doing anything
during the current rendered frame.
This change eliminates the hottest path inside KWin identified by
callgrind.
REVIEW: 102449
The KWin::TimeLine class was only a small wrapper around QTimeLine
without adding anything to QTimeLine what is not present in QTimeLine.
The initial idea was to make it possible to provide more curve shapes.
This is now obsoleted by Qt shipping more useful curves with QTimeLine.
So let's clean up a little bit and use QTimeLine directly instead of
the small wrapper.
All effects are adjusted to use QTimeLine directly.
EffectsHandlerImpl connects to the Workspace signal clientActivated.
The emitting of the signal is slightly moved from before the activation logic
to after the activation logic. This might change behavior in the scripting
component, but the previous code looked wrong.
Client and Unmanaged use a signal to notify that they are about to be closed.
The EffectsHandlerImpl is connected to those signals and emits the appropriate
windowClosed signal to which the effects are connected.
All previously existing windowAdded methods are renamed to slotWindowAdded.
EffectsHandlerImpl is connected to Workspace's clientAdded signal, which is
emitted a little bit earlier than the previous direct method call. This might
change behavior.
Another signal is added to Workspace to signal that an unmanaged is added.
