NOTE: this is not working completely yet, lots of code is still ifdefed
other parts are still broken.
The main difference for the new decoration API is that it is neither
QWidget nor QWindow based. It's just a QObject which processes input
events and has a paint method to render the decoration. This means all
the workarounds for the QWidget interception are removed. Also the paint
redirector is removed. Instead each compositor has now its own renderer
which can be optimized for the specific case. E.g. the OpenGL compositor
renders to a scratch image which gets copied into the combined texture,
the XRender compositor copies into the XPixmaps.
Input events are also changed. The events are composed into QMouseEvents
and passed through the decoration, which might accept them. If they are
not accpted we assume that it's a press on the decoration area allowing
us to resize/move the window. Input events are not completely working
yet, e.g. wheel events are not yet processed and double click on deco
is not yet working.
Overall KDecoration2 is way more stateful and KWin core needs more
adjustments for it. E.g. borders are allowed to be disabled at any time.
Client used to have dedicated methods for different icon sizes instead
of combining all pixmaps into one QIcon. This resulted in various parts
of KWin having different access to the icons:
* effects only got one pixmap of size 32x32
* decorations only got the 16x16 and 32x32 pixmaps combined into a QIcon
* tabbox could request all icon sizes, but only as pixmap
Now all sizes are available in one QIcon allowing to easily access the
best fitting icon in a given UI.
the geometry setting needs to happen out of recursion,
has to be smarter for unmaximizing and also no real
place in TabGroup - the client is no longer tabbed thus
it's not the groups task to manage it's geometry.
BUG: 226881
REVIEW: 106182
FIXED-IN: 4.9.1
Daniel Pastushchak