f820bb3506
In the right combination of circumstances, and given 2 actors (parent actor P with an offscreen effect and child actor C), we may have the following situation happening: - A redraw is queued on the actor C, actors C and P are marked as priv->is_dirty and priv->propagated_one_redraw. - During paint() handling we paint actor P, priv->propagated_one_redraw is turned off. - We recurse into child actor C, priv->propagated_one_redraw is turned off. - A new redraw is queued on actor C, actors C and P are marked as priv->is_dirty and priv->propagated_one_redraw. - The paint() method recurses back, actors C and P get priv->is_dirty disabled, priv->propagated_one_redraw remains set. - At this point queueing up more redraws on actor C will not propagate up, because actor C has priv->propagated_one_redraw set, but the parent actor P has priv->is_dirty unset, so the offscreen effect will not get CLUTTER_EFFECT_PAINT_ACTOR_DIRTY and will avoid repainting actor C. The end result is that actor C does not redraw again, despite requesting redraws. This situation eventually resolves itself through e.g. relayouts on actor P, but may take some time to happen. In order to fix this, consider actors that did get a further redraw request still dirty after paint(). Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2188 Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2353>
Mutter
Mutter is a Wayland display server and X11 window manager and compositor library.
When used as a Wayland display server, it runs on top of KMS and libinput. It implements the compositor side of the Wayland core protocol as well as various protocol extensions. It also has functionality related to running X11 applications using Xwayland.
When used on top of Xorg it acts as a X11 window manager and compositing manager.
It contains functionality related to, among other things, window management, window compositing, focus tracking, workspace management, keybindings and monitor configuration.
Internally it uses a fork of Cogl, a hardware acceleration abstraction library used to simplify usage of OpenGL pipelines, as well as a fork af Clutter, a scene graph and user interface toolkit.
Mutter is used by, for example, GNOME Shell, the GNOME core user interface, and by Gala, elementary OS's window manager. It can also be run standalone, using the command "mutter", but just running plain mutter is only intended for debugging purposes.
Contributing
To contribute, open merge requests at https://gitlab.gnome.org/GNOME/mutter.
It can be useful to look at the documentation available at the Wiki.
Coding style and conventions
See HACKING.md.
Git messages
Commit messages should follow the GNOME commit message
guidelines. We require an URL
to either an issue or a merge request in each commit. Try to always prefix
commit subjects with a relevant topic, such as compositor: or
clutter/actor:, and it's always better to write too much in the commit
message body than too little.
Default branch
The default development branch is main. If you still have a local
checkout under the old name, use:
git checkout master
git branch -m master main
git fetch
git branch --unset-upstream
git branch -u origin/main
git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main
License
Mutter is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for detalis.