Summary:
Add a small getter to query information internally if the backend supports
swap events. Defaults to true as it is the default in the GBM Wayland backend.
Test Plan: i915
Reviewers: #kwin
Subscribers: kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D25298
This reverts commit 9151bb7b9e.
This reverts commit ac4dce1c20.
This reverts commit 754b72d155.
In order to make the fix work, we need to redirect the client window
instead of the frame window. However, we cannot to do that because
Xwayland expects the toplevel window(in our case, the frame window)
to be redirected.
Another solution to the texture bleeding issue must be found.
CCBUG: 257566
CCBUG: 360549
Summary:
Since KDE 4.2 - 4.3 times, KWin doesn't paint window decorations on real
X11 windows, except when compositing is turned off. This leaves us with
a problem. The actual client contents is inside a larger texture with no
useful pixel data around it. This and decoration texture bleeding are
the main factors that contribute to 1px gap between the server-side
decoration and client contents with effects such as wobbly windows, and
zoom.
Another problem with naming frame pixmap instead of client pixmap is
that it doesn't quite go along with wayland. It only makes more difficult
to abstract window quad generation in the scene.
Since we don't actually need the frame window when compositing is on,
there is nothing that holds us from redirecting client windows instead
of frame windows. This will help us to fix the texture bleeding issue
and also help us with the ongoing redesign of the scene.
Test Plan: X11 clients are still composited.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D25610
Summary:
Qt has its own thing where a type might also have corresponding list
alias, e.g. QObject and QObjectList, QWidget and QWidgetList. I don't
know why Qt does that, maybe for some historical reasons, but what
matters is that we copy this pattern here in KWin. While this pattern
might be useful with some long list types, for example
QList<QWeakPointer<TabBoxClient>> TabBoxClientList
in general, it causes more harm than good. For example, we've got two
new client types, do we need corresponding list typedefs for them? If
no, why do we have ClientList and so on?
Another problem with these typedefs is that you need to include utils.h
header in order to use them. A better way to handle such things is to
just forward declare a client class (if that's possible) and use it
directly with QList or QVector. This way translation units don't get
"bloated" with utils.h stuff for no apparent reason.
So, in order to make code more consistent and easier to follow, this
change drops some of our custom typedefs. Namely ConstClientList,
ClientList, DeletedList, UnmanagedList, ToplevelList, and GroupList.
Test Plan: Compiles.
Reviewers: #kwin
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D24950
Summary:
Currently our Scene is quite naive about geometry. It assumes that the
window frame wraps the attached buffer/client. While this is true for X11
clients, such geometry model is not suitable for client-side decorated
clients, in our case for xdg-shell clients that set window geometry
other than the bounding rectangle of the main surface.
In general, the proposed solution doesn't make any concrete assumptions
about the order between frame and buffer geometry, however we may still
need to reconsider the design of Scene once it starts to generate quads
for sub-surfaces.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, romangg, kwin
Tags: #kwin
Maniphest Tasks: T10867
Differential Revision: https://phabricator.kde.org/D24462
Summary:
Compositing in X11 was done time shifted, meaning that we paint first, then
wait one vblank interval length and present on prepareRenderingFrame the
previous paint result. This is supposed to make sure we don't miss the vblank
and in case of block till retrace be able to continue issuing commands and
only shortly before next vblank present.
This is counter-intuitiv, not how we do it on Wayland or even on MESA with X.
The reason seems to be that the GLX backend was in the beginning written
against Nvidia proprietary driver which needed this but nowadays even this
driver defaults to non-blocking behavior on buffer swap.
Therefore remove this legacy anomaly fully and directly present after paint.
We then wait one refresh cycle and in the future can optimize this by delaying
the paint and present till shortly before vsync.
Test Plan: kwin_x11 tested on i915 and Nvidia proprietary driver.
Reviewers: #kwin
Subscribers: zzag, alexeymin, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D23514
Summary:
Selecting not to vsync does not make sense for an X11 compositor. In the end
we want clients to be able to present async if they want to but the compositor
is supposed to send swaps with vsync to the XServer in order to not generate
tearing artifacts.
There was also a detection logic which did some questionable things in case
vsync was not available. I don't think this is necessary at all since we can
just always run a timer to present with or without vsync.
Test Plan: kwin_x11 tested on i915.
Reviewers: #kwin, zzag
Subscribers: zzag, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D23511
Summary:
In order to properly implement xdg_surface.set_window_geometry we need
two kinds of geometry - frame and buffer. The frame geometry specifies
visible bounds of the client on the screen, excluding client-side drop
shadows. The buffer geometry specifies rectangle on the screen that the
attached buffer or x11 pixmap occupies on the screen.
This change renames the geometry property to frameGeometry in order to
reflect the new meaning assigned to it as well to make it easier to
differentiate between frame geometry and buffer geometry in the future.
Reviewers: #kwin
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D24334
Summary:
EffectQuickView/Scene is a convenient class to render a QtQuick
scenegraph into an effect.
Current methods (such as present windows) involve creating an underlying
platform window which is expensive, causes a headache to filter out
again in the rest of the code, and only works as an overlay.
The new class exposes things more natively to an effect where we don't
mess with real windows, we can perform the painting anywhere in the view
and we don't have issues with hiding/closing.
QtQuick has both software and hardware accelerated modes, and kwin also
has 3 render backends. Every combination is supported.
* When used in OpenGL mode for both, we render into an FBO export the
texture ID then it's up to the effect to render that into a scene.
* When using software QtQuick rendering we blit into an image, upload
that into a KWinGLTexture which serves as an abstraction layer and
render that into the scene.
* When using GL for QtQuick and XRender/QPainter in kwin everything is
rendered into the internal FBO, blit and exported as an image.
* When using software rendering for both an image gets passed directly.
Mouse and keyboard events can be forwarded, only if the effect
intercepts them.
The class is meant to be generic enough that we can remove all the
QtQuick code from Aurorae.
The intention is also to replace EffectFrameImpl using this backend and
we can kill all of the EffectFrame code throughout the scenes.
The close button in present windows will also be ported to this,
simplifiying that code base.
Classes that handle the rendering and handling QML are intentionally
split so that in the future we can have a declarative effects API create
overlays from within the same context. Similar to how one can
instantiate windows from a typical QML scene.
Notes:
I don't like how I pass the kwin GL context from the backends into the
effect, but I need something that works with the library separation. It
also currently has wayland problem if I create a QOpenGLContext before
the QPA is set up with a scene - but I don't have anything better?
I know for the EffectFrame we need an API to push things through the
effects stack to handle blur/invert etc. Will deal with that when we
port the EffectFrame.
Test Plan: Used in an effect
Reviewers: #kwin, zzag
Reviewed By: #kwin, zzag
Subscribers: zzag, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D24215
Summary:
So far wayland was used by internal clients to submit raster buffers
and position themselves on the screen. While we didn't have issues with
submitting raster buffers, there were some problems with positioning
task switchers. Mostly, because we had effectively two paths that may
alter geometry.
A better approach to deal with internal clients is to let our QPA use
kwin core api directly. This way we can eliminate unnecessary roundtrips
as well make geometry handling much easier and comprehensible.
The last missing piece is shadows. Both Plasma::Dialog and Breeze widget
style use platform-specific APIs to set and unset shadows. We need to
add shadows API to KWindowSystem. Even though some internal clients lack
drop-shadows at the moment, I don't consider it to be a blocker. We can
add shadows back later on.
CCBUG: 386304
Reviewers: #kwin, davidedmundson, romangg
Reviewed By: #kwin, romangg
Subscribers: romangg, kwin
Tags: #kwin
Maniphest Tasks: T9600
Differential Revision: https://phabricator.kde.org/D22810
Summary:
This has been commented out since 2014, I doubt it will come back.
This is a big amount of code, maintenance will be easier without it.
Reviewers: #kwin, zzag
Reviewed By: #kwin, zzag
Subscribers: romangg, graesslin, kwin
Tags: #kwin, #documentation
Differential Revision: https://phabricator.kde.org/D23069
Summary:
This patch is a first take at splitting up of the Compositor class into
Wayland and X11 child classes.
In this first patch we mostly deal with setup and teardown procedures.
A future goal is to further differentiate the compositing part itself too.
Test Plan: Manually X from VT and Wayland nested. Autotests pass.
Reviewers: #kwin
Subscribers: sbergeron, anthonyfieroni, zzag, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D22195
Summary:
So far we were following a bit unique and rare doxygen comment style:
/**
* Contents of the comment.
**/
Doxygen comments with this style look balanced and neat, but many people
that contribute to KWin don't follow this style. Instead, they prefer
more traditional doxygen comment style, i.e.
/**
* Contents of the comment.
*/
Reviewing such changes has been a bit frustrating for me (so selfish!)
and for other contributors.
This change switches doxygen comment style in KWin to a more traditional
style. The main reason for doing this is to make code review process easier
for new contributors as well us.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D22812
Summary:
Currently code base of kwin can be viewed as two pieces. One is very
ancient, and the other one is more modern, which uses new C++ features.
The main problem with the ancient code is that it was written before
C++11 era. So, no override or final keywords, lambdas, etc.
Quite recently, KDE compiler settings were changed to show a warning if
a virtual method has missing override keyword. As you might have already
guessed, this fired back at us because of that ancient code. We had
about 500 new compiler warnings.
A "solution" was proposed to that problem - disable -Wno-suggest-override
and the other similar warning for clang. It's hard to call a solution
because those warnings are disabled not only for the old code, but also
for new. This is not what we want!
The main argument for not actually fixing the problem was that git
history will be screwed as well because of human factor. While good git
history is a very important thing, we should not go crazy about it and
block every change that somehow alters git history. git blame allows to
specify starting revision for a reason.
The other argument (human factor) can be easily solved by using tools
such as clang-tidy. clang-tidy is a clang-based linter for C++. It can
be used for various things, e.g. fixing coding style(e.g. add missing
braces to if statements, readability-braces-around-statements check),
or in our case add missing override keywords.
Test Plan: Compiles.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, apol, romangg, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D22371
Summary:
Code that destroys all scene windows when finishing compositing is not
readable. E.g. can you tell what this piece of code is doing without
looking into the source code of Scene::windowClosed?
foreach (Client * c, Workspace::self()->clientList())
m_scene->windowClosed(c, NULL);
This change intoduces removeToplevel(as well its counterpart) method to
the Scene class. The name of the new method much better describes what
we're doing.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18210
Summary:
We have a mix of different doxygen comment styles, e.g.
/*!
Foo bar.
*/
/**
* Foo bar.
*/
/** Foo bar.
*/
/**
* Foo bar.
*/
/**
* Foo bar.
**/
To make the code more consistent, this change updates the style of all
doxygen comments to the last one.
Test Plan: Compiles.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18683
Summary:
We initialize all fields of Phase2Data at once, so the constructors seem
to be redundant.
Reviewers: #kwin, graesslin
Reviewed By: #kwin, graesslin
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18207
Summary:
213239a0ea tried to address the case when
a wayland client gets shadow after it was mapped, but because of poor
testing from my side, another bug was introduced. If a decoration tooltip
or the user actions popup is shown, then in some cases it can be blank.
Usually, SurfaceInterface::shadowChanged proceeds SurfaceInterface::sizeChanged,
so when the shadow is installed, window quads cache is rebuilt. But
because shell client already knows the geometry of the internal client,
goemetryShapeChanged is not emitted, thus the cache is not updated.
It would be better just to invalidate the cache when the shadow is
installed, uninstalled, or updated. This reduces the number of
unnecessary invocations of Scene::Window::buildQuads and also moves
handling of the window quads cache away from the Shadow class.
BUG: 399490
FIXED-IN: 5.15.0
Test Plan: Decoration tooltips are no longer blank.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, graesslin, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D17215
Summary:
Under wayland we support high DPI putting by putting a separation
between the logical co-ordinate system and the resolution of rendered
assets.
When a window is on a high DPI screen, we should render at the higher
resolution.
Like the window scaling this handles any combination of a 2x scaled
decoration being rendered on a 1x screen or vice versa.
---
This patch is a bit different from the other scaling stuff. We have to
generate the quads *before* we have an updated texture with the new
scale. This means the scale isn't attached to the buffer like elsewhere.
That's why I added a property in TopLevel so there's still one canonical
source and things can't get out of sync.
BUG: 384765
Test Plan:
Crystal clear breeze and oxygen decos on my @2x display
Drag windows to attached @1x display, things still look OK when across 2
screens
Changing the scale of a screen updated the decos instantly
Reviewers: #plasma, graesslin
Reviewed By: #plasma, graesslin
Subscribers: graesslin, plasma-devel, kwin, #kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D8600
Summary:
Unfortunately a rather large change which required more refactoring than
initially expected. The main problem was that some parts needed to go
into platformsupport so that the platform plugins can link them. Due to
the rather monolithic nature of scene_opengl.h a few changes were
required:
* SceneOpenGL::Texture -> SceneOpenGLTexture
* SceneOpenGL::TexturePrivate -> SceneOpenGLTexturePrivate
* texture based code into dedicated files
* SwapProfiler code into dedicated files
* SwapProfiler only used in x11 variants
* Safety checks for OpenGL scene moved into the new plugin
* signal declared in SceneOpenGL moved to Scene, so that we don't need
to include SceneOpenGL in composite
Test Plan: Nested OpenGL compositor works
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7740
Summary:
We had a few places (e.g. DebugConsole, Platform) where the Scene was
cased into a SceneOpenGL to access the backend and get the extensions.
This change simplifies that by adding a virtual method to Scene directly
which is implemented in SceneOpenGL and returns the backend's
extensions.
Thus the casts to SceneOpenGL are no longer required.
Test Plan:
Opened debug console to verify extensions are listed,
triggered Outline to verify the sharing QPA context gets created.
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7734
Needed by testing of QPainter scene to access the back buffer. Exposed
as a virtual method in Scene, so that the test does not have to cast to
SceneQPainter.
Summary:
First step for loading the compositor Scenes through plugins. The general
idea is that we currently needlessly pull in all the Scenes although only
one will be used.
E.g. on X11 we pull in QPainter, although they are not compatible. On
Wayland we pull in XRender although they are not compatible.
Furthermore our current Scene creation strategy is not really fault
tolerant and can create situations where we don't get a compositor. E.g
on fbdev backend the default settings won't work as it does not support
OpenGL.
Long term I want to tackle those conceptional problems together:
we try to load all plugins supported by the current platform till we have
a scene which works. Thus on Wayland we don't end up in a situation where
we don't have a working compositor because the configuration is bad.
To make this possible the switch statement in the Scene needs to go and
needs to be replaced by a for loop iterating over all the available
scenes on the platform. If we go there it makes sense to replace it
directly with a plugin based approach.
So this is a change which tackles the problem by first introducing the
plugin loading. The xrender based scene (as it's the most simple one)
is moved into a plugin. It is first tried to find a scene plugin and only
if there is none the existing code is used.
Test Plan: Tested all scenes
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7232
Summary:
So far EffectsHandlerImpl directly accessed SceneQPainter::painter
through a dynamic cast. If in future the QPainter based compositor should
be moved into a plugin we cannot access it through a dynamic cast.
To solve this problem the painter method is moved into Scene as
a virtual method returning a sane default value.
Reviewers: #kwin, #plasma
Subscribers: plasma-devel
Tags: #plasma
Differential Revision: https://phabricator.kde.org/D7214
Summary:
So far EffectsHandlerImpl directly accessed SceneXrender::bufferPicture
through a dynamic cast. If in future the XRender based compositor should
be moved into a plugin we cannot access it through a dynamic cast.
To solve this problem the bufferPicture method is moved into Scene as
a virtual method returning a sane default value.
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7207
This change is needed for Wayland screen recording apps to work
correctly. With this change the cursor is actually visible using GBM
buffer passing protocol.
Previously OpenGL backend did not support software cursor. If launching
in DRM/OpenGL mode with flicked on software cursor it only rendered
scene, but not the cursor image.
Differential Revision: https://phabricator.kde.org/D6186
Summary:
WindowVertex contains the x position and also the relative texture x position
Our textures are scaled bigger than kwin's resolution, so this makes sure we set the right
texture position.
Otherwise our final array ends up using 0 to 0.5 of the texture, not 0 to 1.
Test Plan:
Opened some 2x windows, on a 1x output.
It looked how it should do, instead of it being double the size and cropped
Tested some things that use quads, like wobbly windows
Reviewers: #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D3502
Summary:
On Wayland per output rendering is performed and paintScreen is invoked
for every output. Some effects need the information which output is
currently being rendered as otherwise e.g. FBO access could fail.
This change adds the current output geometry to ScreenPaintData. On X11
(all outputs one geometry) this information is not set and a null rect
is returned. That way the effects can also easily check which rendering
mode is used.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3058
Summary:
If a buffer gets destroyed the texture created from it is still valid.
In such a situation the OpenGLWindowPixmap should return true for isValid
and not false as it did. Similar in QPainter compositor the pixmap is
valid if there is an image copied from the buffer.
This change ensures that for example minimizing an XWayland window
still has a texture during the minimize animation.
BUG: 368440
Test Plan:
Minimize animation plays for X windows and minimized windows
are shown in present windows.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D2724
Summary:
So far when deleting a Shadow we used deleteLater which caused it
to be deleted in the next event cycle. This could in worst case result
in the Shadow being deleted after compositing got suspended. Thus the
Shadow not getting removed from the DecorationShadowCache which in
turn would mess up rendering on resume of compositing as the cache
returns a texture created for a different context.
BUG: 361154
FIXED-IN: 5.7.4
Reviewers: #kwin, #plasma
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D2483
Summary:
A new method to tell the effects system whether the compositor scene
is able to drive animations. E.g. on software emulation (llvmpipe) it's
better to not do any animations at all.
This information can be used by effects to adjust their behavior, e.g.
PresentWindows could skip transitions or effects can use it in their
supported check to completely disable themselves.
As a first step all scripted effects are considered to be unsupported
if animations are not supported. They inherit AnimationEffect and are
all about driving animations.
The information whether animations are supported comes from the Scene.
It's implemented in the following way:
* XRender: animations are always supported
* QPainter: animations are never supported
* OpenGL: animations are supported, except for software emulation
In addition - for easier testing - there is a new env variable
KWIN_EFFECTS_FORCE_ANIMATIONS to overwrite the selection.
Reviewers: #kwin, #plasma
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D2386
Summary:
Rational: unredirect fullscreen windows is a weird beast. It's intended
to make fullscreen windows "faster" by not compositing that screen. But
that doesn't really work as KWin jumps out of that condition pretty
quickly. E.g. whenever a tooltip window is shown. KWin itself has a
better functionality by supporting to block compositing completely.
The complete code was full of hacks around it to try to ensure that
things don't break.
Overall unredirect fullscreen has always been the odd one. We had it
because a compositor needs to have it, but it never got truly integrated.
E.g. effects don't interact with it properly so that some things randomly
work, others don't. Will it trigger the screenedge, probably yes, but
will it show the highlight: properly no.
By removing the functionality we finally acknowledge that this mode is
not maintained and has not been maintained for years and that we do not
intend to support it better in future. Over the years we tried to make
it more and more hidden: it's disabled for Intel GPUs, because it used
to crash KWin. It's marked as an "expert" option, etc.
It's clearly something we tried to hide from the user that it exists.
For Wayland the whole unredirect infrastructure doesn't make sense
either. There is no such thing as "unredirecting". We might make use
of passing buffers directly to the underlying stack, but that will be
done automatically when we know it can be done, not by some magic is
this a window of specific size.
Test Plan:
Compiles, cannot really test as I am an Intel user who never
had that working.
Reviewers: #kwin, #plasma, #vdg
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D2180
Summary:
The idea behind this autotest is inspired by bug 356328 which produced
incorrect rendering results. Also it's inspired by openQA which performs
image reference comparisons.
This test case tries to go further. It creates reference images which
must match the rendering result exactly. So far the test case verifies
the start condition - kwin started and one frame is rendered with default
cursor in the middle of the screen. And it verifies the moving of the
cursor without any windows shown. Whenever the cursor moves a repaint
should be triggered and the old and new area should be properly
repainted.
To support this the test needs some minor changes in KWin:
* Scene provides a frameRendered signal - needed for waiting on frame
* Scene and SceneQPainter are exported
* SceneQPainter provides access to it's Backend, so that we get to the
backbuffer
* ScriptedEffectLoader is exported for getting a list of all scripted
effects - (we don't want fade to manipulate the rendering)
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D2046
This change introduces a tree for WindowPixmap. A WindowPixmap can
have a parent WindowPixmap and children. Each child represents a
SubSurface and references the buffer of that SubSurface.
The tree of WindowPixmaps is updated each time updateBuffer is called.
If there are new SubSurfaces new WindowPixmaps are created, for removed
SubSurfaces the old WindowPixmap gets removed. Also the ordering is
updated to reflect the current state.
This is currently rather expensive and should be changed to only rebuild
the tree if it actually changed.
The screen projection matrix is needed if an effect wants to customize
the modelview projection matrix while rendering a window and keeping
the currently applied screen projection and transformation.
With this change a new ctor overload is added to ScreenPaintData
which allows passing a projection matrix through the effects. This
allows effects to put up custom shaders with a shared projection matrix
and without having to calculate it themselves.
The projection matrix is a read-only information for the effects. There
is no way to change or overwrite it.
This describes an additional offset for the client content. On X11
our client content position matches with the window - the window
decoration is part of the overall content coordinate system.
On Wayland the content is an own texture starting at 0/0. Thus a
mapping to texture coordinates will be required when server side
decorations are provided. The new information is used in the scene's
to adjust the rendering and generating of quads.
This change introduces a mechanism for internal windows to be rendered
to a QOpenGLFramebufferObject to be composited using the texture bound
to the FBO. This is useful for in-process rendering (e.g. QtQuick) and
at the same time bypassing the windowing system.
The OpenGL context of the QOpenGLFramebufferObject needs to be sharing
with the compositing OpenGL context.
EglWaylandBackend gains support for creating textures from a
BufferInterface. At the same time it loses the possibility to use
the Xcb shm extension to load the texture. That is Xwayland is
required.
In order to support it in a better way the WindowPixmap is passed
to the Texture for loading and updating. Which is then passed to the
backend specific implementation.
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.
