Effects are given the interval between two consecutive frames. The main
flaw of this approach is that if the Compositor transitions from the idle
state to "active" state, i.e. when there is something to repaint,
effects may see a very large interval between the last painted frame and
the current. In order to address this issue, the Scene invalidates the
timer that is used to measure time between consecutive frames before the
Compositor is about to become idle.
While this works perfectly fine with Xinerama-style rendering, with per
screen rendering, determining whether the compositor is about to idle is
rather a tedious task mostly because a single output can't be used for
the test.
Furthermore, since the Compositor schedules pointless repaints just to
ensure that it's idle, it might take several attempts to figure out
whether the scene timer must be invalidated if you use (true) per screen
rendering.
Ideally, all effects should use a timeline helper that is aware of the
underlying render loop and its timings. However, this option is off the
table because it will involve a lot of work to implement it.
Alternative and much simpler option is to pass the expected presentation
time to effects rather than time between consecutive frames. This means
that effects are responsible for determining how much animation timelines
have to be advanced. Typically, an effect would have to store the
presentation timestamp provided in either prePaint{Screen,Window} and
use it in the subsequent prePaint{Screen,Window} call to estimate the
amount of time passed between the next and the last frames.
Unfortunately, this is an API incompatible change. However, it shouldn't
take a lot of work to port third-party binary effects, which don't use the
AnimationEffect class, to the new API. On the bright side, we no longer
need to be concerned about the Compositor getting idle.
We do still try to determine whether the Compositor is about to idle,
primarily, because the OpenGL render backend swaps buffers on present,
but that will change with the ongoing compositing timing rework.
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 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:
Currently, effects like Maximize, Slide Back have problems with setting
WindowForceBlurRole. They store previous state of WindowForceBlurRole.
This is wrong. Instead they should either ignore previous state of
WindowForceBlur or refcount forced role.
There's no need for refcounting right now. For example, if several effects
force blur or background contrast, they are most likely in a conflict.
Please notice that the Desktop Grid effect uses the Present Windows
effect only to calculate transformations.
Some other problems with the code that sets WindowForceBlurRole:
* Maximize effect stores previous state of WindowForceBlurRole only
for one window. It ignores the fact that there could be several
active maximize animations;
* Desktop Grid/Present Windows/Slide back don't clean after themselves.
So, after using those effects for good amount of times, memory usage
will bump.
Test Plan:
* Enabled blur for Konsole
* Maximized Konsole
* Activated Present Windows
* Activated Desktop Grid
* Raised another window(to trigger Slide Back)
Reviewers: #kwin, fredrik
Reviewed By: fredrik
Subscribers: fredrik, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D13479
This method replaces the X-KDE-ORDERING property in the Effect's desktop
files. This change is a preparation step for integrating the new Effect
Loader which doesn't read the ordering information. Thus it needs to be
provided by the Effect itself so that the EffectsHandler can properly
insert it into the chain.
Also for the built-in Effects on the long run it doesn't make much sense
to install the desktop files. And binary plugin effects will migrate to
json metadata which also doesn't have the KService::Ptr. Thus overall it
simplifies to read this information directly from the Effect.
Each effect is able to declare itself as currently being active,
that is transforming windows or painting or screen or doing anything
during the current rendered frame.
This change eliminates the hottest path inside KWin identified by
callgrind.
REVIEW: 102449
This needs to be improved in core. Currently ClientGroup does not yet
emit signals, as it would be difficult to connect them. Nevertheless
the effects dependency should be removed.
EffectsHandlerImpl connects to the Workspace signal clientActivated.
The emitting of the signal is slightly moved from before the activation logic
to after the activation logic. This might change behavior in the scripting
component, but the previous code looked wrong.
All previously existing windowAdded methods are renamed to slotWindowAdded.
EffectsHandlerImpl is connected to Workspace's clientAdded signal, which is
emitted a little bit earlier than the previous direct method call. This might
change behavior.
Another signal is added to Workspace to signal that an unmanaged is added.
