In order to notice when the geometry changes a new signal is
added to toplevel and both Unmanaged and Client connect all their
signals which are emitted whenever the geometry changes in some way
to this new signal.
Shadow connects to the signal and updates the quads and region
whenever the size changes.
The Shadow is clearly an aspect of the compositor. Therefore the
Shadow has to be owned and controlled by the Scene::Window.
Nevertheless Toplevel needs to know about the Shadow cause of reading
the property.
Unmanaged needs to repaint the complete geometry including shadow
when it ends compositing. Therefore we need to track the shadow
passing to deleted correctly. Disadvantage: when turning off
compositing the shadow is kept. Need to solve in a better way!
For a complete documentation of new functionality refer to:
http://community.kde.org/KWin/Shadow
The current implementation includes a new Shadow class and Toplevel
holds a pointer to an instance of this class. The Shadow class reads
the data from the X11 Property. There is one extended class located
in SceneOpenGL to render the shadow.
Compositor is adjusted to include the shadow region into the painting
passes.
Implementation for XRender still missing and Shadow needs to respond
to size changes of the Toplevel to update cached shadow region and
WindowQuads.
