So far updating the cursor image was not really defined. It was possible
to use the cursor image from the wayland seat or have a custom set cursor
image. But there are no rules in place to decide which one to use when.
With this change a dedicated CursorImage class is introduced which tracks
the cursor image changes on the seat, on the decoration, in the effects
and so on. In addition it tracks which is the current source for the
image, that is whether e.g. the cursor from the seat or from effects
override should be used. Whenever the cursor image changes a signal is
emitted, which is connected to the signal in AbstractBackend.
Based on that the backends can directly show the image. The existing
code in the backends to install a cursor shape or to install the cursor
from the server is completely dropped. For the backend it's irrelevant
from where the image comes from.
A new feature added is that the cursor image is marked as rendered. This
is then passed on to the frame rendered in the Surface and thus animated
cursors are finally working. Unfortunately animated cursors are broken in
Qt (see https://bugreports.qt.io/browse/QTBUG-48181 ).
The backend is prepared for managing multiple x11 windows. Currently
it's still only one window, but it's all internally working through
the architecture for multiple windows.
When pressing right control key the input gets grabbed/released.
The grab is for both keyboard and pointer and pointer is also confined
to the window.
How to grab/ungrab is added to the window title.
Each of the backends becomes a plugin. This allows kwin_wayland to load
the requested plugin and kwin itself doesn't need to link all the
libraries needed. E.g. libdrm is no longer linked if running kwin_x11.
Also this allows to create backends for the non-standard EGL platforms
(examples could be raspberrypi or Android devices).
The aim is to be able to create a plugin for each of the backends.
The following directories are created:
* backends/drm
* backends/fbdev
* backends/wayland
* backends/x11
