9b50215008
We currently support only one case where an actor can get mapped or unmapped during painting, that is using _clutter_actor_enable_paint_unmapped() (although we could arguably do a better job explicitely forbidding it in other cases). This function is called when painting ClutterClone or MetaWindowActors during screensharing. It temporarily (fake) realizes and maps the actor and all its children so it can get painted. Now a problem will appear when we'll start coupling layout and the mapped state of actors more closely with the next commit: Since enable_paint_unmapped() is meant to be enabled and disabled during every clone paint, we also notify the "mapped" property twice on every clone paint. That means with the next commit we would queue a relayout for the source actor on every clone paint. To avoid this unnecessary work, check whether we're being painted while unmapped using the new unmapped_paint_branch_counter. Then avoid queuing relayouts or invalidating paint volumes in that case. https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1366
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.
The coding style used is primarily the GNU flavor of the GNOME coding
style
with some minor additions such as preferring stdint.h types over GLib
fundamental types, and a soft 80 character line limit. However, in general,
look at the file you're editing for inspiration.
Commit messages should follow the GNOME commit message guidelines. We require an URL to either an issue or a merge request in each commit.
License
Mutter is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for detalis.