At the moment, our frame scheduling infrastructure is still heavily
based on Xinerama-style rendering. Specifically, we assume that painting
is driven by a single timer, etc.
This change introduces a new type - RenderLoop. Its main purpose is to
drive compositing on a specific output, or in case of X11, on the
overlay window.
With RenderLoop, compositing is synchronized to vblank events. It
exposes the last and the next estimated presentation timestamp. The
expected presentation timestamp can be used by effects to ensure that
animations are synchronized with the upcoming vblank event.
On Wayland, every outputs has its own render loop. On X11, per screen
rendering is not possible, therefore the platform exposes the render
loop for the overlay window. Ideally, the Scene has to expose the
RenderLoop, but as the first step towards better compositing scheduling
it's good as is for the time being.
The RenderLoop tries to minimize the latency by delaying compositing as
close as possible to the next vblank event. One tricky thing about it is
that if compositing is too close to the next vblank event, animations
may become a little bit choppy. However, increasing the latency reduces
the choppiness.
Given that, there is no any "silver bullet" solution for the choppiness
issue, a new option has been added in the Compositing KCM to specify the
amount of latency. By default, it's "Medium," but if a user is not
satisfied with the upstream default, they can tweak it.
The main advantage of SPDX license identifiers over the traditional
license headers is that it's more difficult to overlook inappropriate
licenses for kwin, for example GPL 3. We also don't have to copy a
lot of boilerplate text.
In order to create this change, I ran licensedigger -r -c from the
toplevel source directory.
Summary:
Currently, we have only one shell client type - XdgShellClient. We use
it when we are dealing with Wayland clients. But it isn't really a good
idea because we may need to support shell surfaces other than xdg-shell
ones, for example input panel surfaces.
In order to make kwin more extensible, this change replaces all usages
of the XdgShellClient class with the AbstractClient class.
Test Plan: Existing tests pass.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D27778
Summary:
Rename ShellClient to XdgShellClient in order to reflect that it
represents only xdg-shell clients.
Test Plan: Compiles, tests still pass.
Reviewers: #kwin
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D23589
Summary:
Adds an autotest to show that KWin fails an assertion when a client tries to
resize a sub-surface.
Since it is the first autotest dealing with sub-surfaces explicitly additional
autotest helpers are introduced to allow that.
We also add a new signal in Compositor to spy on to know when the buffer swap
has been completed.
Test Plan:
Test fails as expected:
```
QFATAL : KWin::BufferSizeChangeTest::testShmBufferSizeChangeOnSubSurface() ASSERT: "image.size() == m_size" in file /home/roman/dev/kde/src/kde/workspace/kwin/platformsupport/scenes/opengl/abstract_egl_backend.cpp, line 394
FAIL! : KWin::BufferSizeChangeTest::testShmBufferSizeChangeOnSubSurface() Received a fatal error.
Loc: [Unknown file(0)]
Totals: 4 passed, 1 failed, 0 skipped, 0 blacklisted, 367ms
********* Finished testing of KWin::BufferSizeChangeTest *********
```
Reviewers: #kwin, zzag
Subscribers: zzag, graesslin, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18452
