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:
We repeat quite a lot of code that finds an output by xcb_window_t and
translates global X11 screen coordinates to output coordinates.
Test Plan: Compiles.
Reviewers: #kwin, gladhorn
Reviewed By: #kwin, gladhorn
Subscribers: gladhorn, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D23947
Summary:
Get the pixel size directly from the always available output device
interface instead of saving an additional copy in the backends.
Test Plan: Nested Wayland, Drm, virtual backends tested.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Maniphest Tasks: T11459
Differential Revision: https://phabricator.kde.org/D23495
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:
Represent outputs in the X11 session via AbstractOutput. For that we
move all Wayland specific parts of AbstractOutput into a new subclass
AbstractWaylandOutput and let the outputs of our Wayland backends inherit
from there.
This should allow us to get rid of the Screens class later on.
Test Plan: Manually in X session.
Reviewers: #kwin, zzag, davidedmundson
Reviewed By: #kwin, zzag, davidedmundson
Subscribers: ngraham, zzag, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D19208
Summary:
To homogenize our backends and as another step to remove the Screens class
use the AbstractOutput class in the windowed X11 backend.
Test Plan: Manually in X session.
Reviewers: #kwin, zzag
Reviewed By: #kwin, zzag
Subscribers: davidedmundson, zzag, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D19207
