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Daniel van Vugt 88600c8985 clutter/stage-cogl: Ensure redraw_clip is a superset of fb_clip_region
Initially we generate the new part of fb_clip_region from the new part
of redraw_clip, scale it up and clamp. But the clamping means the new
part of fb_clip_region might now represent a slightly larger area than
the new part of redraw_clip, by one pixel.

In some rare cases where a foreground actor honours redraw_clip, but
the background actor does not (meaning it might fill all fb_clip_region),
you could find 1px rendering glitches in that gap as the background
actor paints there but the foreground actor does not.

To ensure such glitches can never happen we now regenerate the final
redraw_clip as a clamped superset of the final fb_clip_region. That's
the minimum area we must paint to ensure no gaps appear inside
fb_clip_region.

Although the fix here sounds like the intent of the old code, the old
code forgot to include the new part of fb_clip_region in the clamping
of the final redraw_clip. So the new part of redraw_clip was sometimes
kept too small for the new part of fb_clip_region.

We also move the code to the main path because technically it's also
needed when `has_buffer_age == FALSE`.

Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1500
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1554>
2021-01-27 17:15:01 +08:00
.gitlab/issue_templates gitlab: Add missing < in markdown comment tag 2020-02-14 03:10:28 +00:00
.gitlab-ci ci: Install Xwayland from git 2021-01-25 15:14:35 +00:00
clutter clutter/stage-cogl: Ensure redraw_clip is a superset of fb_clip_region 2021-01-27 17:15:01 +08:00
cogl kms: Add symbolic page flips and cogl frame infos 2021-01-22 16:47:08 +00:00
data xwayland: Enable Xwayland on demand by default 2021-01-19 09:33:33 +01:00
doc Add MetaGravity and replace X11 equivalent with it 2020-02-29 21:01:50 +00:00
meson build: Add postinstall script 2019-08-27 09:57:54 +00:00
po Update Galician translation 2021-01-25 19:05:32 +00:00
src shaped-texture: Update the full bounding box of each clip rectangle 2021-01-27 17:05:38 +08:00
subprojects build: bump ABI to sysprof-capture-4 2020-07-28 11:13:30 -07:00
tools tools: Remove obsolete ppa-magic.py 2018-11-30 11:12:12 +08:00
.gitignore build: bump ABI to sysprof-capture-4 2020-07-28 11:13:30 -07:00
.gitlab-ci.yml ci: Install Xwayland from git 2021-01-25 15:14:35 +00:00
config.h.meson xwayland: Check for listenfd option 2021-01-22 11:40:30 +01:00
COPYING
meson_options.txt xwayland: Check X11 clients prior to terminate Xwayland 2021-01-18 17:52:22 +01:00
meson.build xwayland: Check for listenfd option 2021-01-22 11:40:30 +01:00
mutter.doap mutter.doap: Add marge-bot as a maintainer 2020-11-16 11:59:45 +01:00
NEWS Tag release 40.alpha.1.1 2021-01-14 17:22:43 +01:00
README.md README: Elaborate coding style and commit message guidelines 2020-10-28 07:28:55 +00:00

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

The coding style used is primarily the GNU flavor of the GNOME coding style with some additions:

  • Use regular C types and stdint.h types instead of GLib fundamental types, except for gboolean, and guint/gulong for GSource ids and signal handler ids. That means e.g. uint64_t instead of guint64, int instead of gint, unsigned int instead of guint if unsignedness is of importance, uint8_t instead of guchar, and so on.

  • Try to to limit line length to 80 characters, although it's not a strict limit.

  • Usage of g_autofree and g_autoptr are encouraged. The style used is

  g_autofree char *text = NULL;
  g_autoptr (MetaSomeThing) thing = NULL;

  text = g_strdup_printf ("The text: %d", a_number);
  thing = g_object_new (META_TYPE_SOME_THING,
                        "text", text,
                        NULL);
  thinger_use_thing (rocket, thing);
  • Declare variables at the top of the block they are used, but avoid non-trivial logic among variable declarations. Non-trivial logic can be getting a pointer that may be NULL, any kind of math, or anything that may have side effects.

  • Instead of boolean arguments in functions, prefer enums or flags when they're more expressive.

  • Use g_new0() etc instead of g_slice_new0().

  • Initialize and assign floating point variables (i.e. float or double) using the form floating_point = 3.14159 or ratio = 2.0.

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.

License

Mutter is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for detalis.