This new backend allows to start a kwin_wayland server nested on an
X-Server by using a normal X11 window as output. This allows testing
kwin_wayland without needing to start another Wayland server first.
The behavior is triggered by using new command line arguments:
--windowed
--x11-display=<:0>
With optional --width and --height arguments.
In this mode the WaylandBackend is not created at all.
So far the backend is not fully integrated yet and only the QPainter
backend supports this mode.
The concept of Buffers do not match WindowPixmap perfectly. With X11
we had a pixmap as long as the size was the sime, then it got discarded.
With Wayland we get a new Buffer whenever the window gets damaged.
Furthermore the Buffer might get destroyed any time (especially if the
client disconnects) or the data becomes invalid (it's a shm section after
all).
This adds some constraints on how the Buffer can be used. It's suggested
that the implementing sub-classes do a deep copy of the Buffer's data
when accessing it. For OpenGL that's rather obvious, for QPainter it
needs a dedicated QImage::copy.
WindowPixmap holds a pointer to the currently used Buffer, but doesn't
guarantee that it stays valid. Every time the window gets damaged, the
pointer needs to be updated.
The QPainter based scene is the first to implement support for Buffers:
on creation a deep copy is performed, on damage the changed parts are
painted into the deep copy.
Move the buffer-swap-pending state from the compositing backends to
the Compositor class. The Compositor is the only class that needs to
access the state, and this way it to do it without calling through
a chain of virtual functions. This commit adds two new functions to
Compositor; aboutToSwapBuffers() and bufferSwapComplete(). The
backends call these functions to set and reset the buffer-swap-pending
state.
This commit also renames a number of functions and variables to make
their meaning clear.
The act of promoting the contents of the back buffer to become the
contents of the front buffer is referred to as posting the buffer,
presenting the buffer, or swapping the buffers; rendering the buffer
is what paintScreen() does.
Moved from wayland_backend.[h|cpp] to buffer.[h|cpp] and
shm_pool.[h|cpp]. Buffer is slightly adjusted to have the ShmPool
passed in as a ctor argument and the ctor is private and friended with
ShmPool, so that it can only be constructed from ShmPool.
A Surface class is split out which holds a wl_surface and supports
attaching a buffer, setting the damage and emitting a signal when the
frame callback got called.
It doesn't come with a unit test yet as it first needs the ShmPool
and Buffer properly split out to easily set it up.
Surprisingly the DecorationShadow is modelled after the Shadow in KWin.
It provides the same offsets and a QImage exactly like the OpenGL
implementation needs it. This makes it easy to hook it into our existing
Shadow implementation with only a few changes.
Shadow now first tries to create a Shadow from the Decoration and only
if that fails it tries the X11 property. The pixmaps are not initialized
for the DecorationShadow and because of that currently only the OpenGL
backend gets initialized for DecorationShadows. The other backends might
need adjustments and also a transition to just using one image.
The Renderer gets reparented to the Deleted. While passing it to
the Deleted the Scene's implementation can ensure that the buffers
are up to date. After passing to Deleted it's no longer allowed to
call the render method.
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.
Returns true if the OperationMode requires KWin to composite to a
Wayland surface. This replaces the checks for the WaylandBackend or env
variable used so far in the construction of the Scene.
This compositor uses only the QPainter API to perform rendering. The
window's X Pixmap is mapped to a QImage using XShm. As rendering backend
a QImage is used.
The new compositing type "QPainterCompositing" is introduced. Effects
need to be adjusted to explicitly check the compositing type and no
longer assume the compositing type is XRender if it's not OpenGL.
This compositor can be selected with using "Q" as the value for
KWIN_COMPOSE env variable or setting the config value to "QPainter".
The GUI is not yet adjusted to select this compositor.
The QPainter scene provides currently the following features:
* 2D transformations (translation and scalation)
* opacity modifications
* rendering of decorations (new PaintRedirector sub class)
* rendering of shadows
* rendering of effect frames
* rendering to a Wayland surface
The following features are currently not provided:
* saturation changes
* brightness changes
* 3D transformations
* rendering to X Overlay window
* offscreen rendering (e.g. needed for screen shot effect)
* custom rendering in the effects to the current back buffer
