b98ebe60b2
On x11 we emulate pointer events from touch events as long as there's only one touchpoint on screen, this obviously leads to x11 sending us crossing events triggered by the emulated pointer. Now if we get a leave event and set the stage of the ClutterInputDevice to NULL, new touch events will be discarded by clutters backend because the core pointer doesn't have a stage associated. This means Mutter completely loses state of a touchpoint as soon as it crosses a shell actor. An easy reproducer for this issue is to start the four-finger-workspace gesture above a window and to move the pointer emulating touch outside of the window, this will freeze the gesture as the gesture no longer receives touch events. To fix this, stop tracking stage changes on crossing events and simply leave the ClutterInputDevice stage as-is. In our case there is only one stage anyway and that won't change in the future. https://gitlab.gnome.org/GNOME/mutter/merge_requests/423
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.