Introduce MetaCompositorX11, dealing with being a X11 compositor, and
MetaCompositorServer, being a compositor while also being the display
server itself, e.g. a Wayland display server.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/727
Double negations are the spawn of the devil, and is_non_opaque() is
used like that to find out if it's opaque most often, change the
function name to see the glass half full.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/698
The MetaBackgroundActor was ignoring the unobscured area altogether,
and just painted according to the clip area. Check the unobscured
area too, as it might well be covered by client windows.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/698
Wayland clients do this through the opaque region in the surface
actor. However X11 clients were considered fully transparent for
culling purposes, which may result in mutter painting other bits
of the background or other windows that will be painted over in
reality.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/698
We want to clip it away if 1) The window is fully opaque or
2) If it's translucent but has a frame (as explained in the comment
above). The code didn't quite match and we were only applying it on
case #2.
Case #1 is far more common, and saves us from pushing some drawing
that we know will be covered in the end.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/698
Make it so it returns the closest ancestry MetaWindowActor if it
is a MetaSurfaceActor.
We need this for Wayland subsurfaces, so we can support actions like
Meta+Drag on them.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/604
Saves us from using MetaCompositor API, at a point where it might not
be initialized yet. Use the same window directly, since we already
have it handy.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/672
We need to set XdndAware and XdndProxy on the stage window if running
a X11 compositor, this is not necessary on wayland.
Takes over gnome-shell code doing this initialization.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/667
Waking up gnome-shell and triggering JavaScript listeners of
`size-changed` every time a window was only moved was wasting a lot
of CPU.
This cuts the CPU requirement for dragging windows by around 22%.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/568
The way code was structured made it easy to misunderstand things as the
surface actor of a window actor could change over time. So is not the
case, however, the intention of the corresponding "update" function was
so that a surface actor could be assigned to a window actor as soon as
the X11 window was associated with its corresponding wl_surface, if the
window in question came from Xwayland.
Restructure the code and internal API a bit to make it clear that a
window actor only once gets a surface actor assigned to it, and that it
after that point never changes.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/659
X11 actors need to release the server data (pixmap and damage) before the
display is closed.
During the close phase all the windows are unmanaged and this causes the window
actors to be removed from the compositor, unsetting their actor surface.
However, in case a window is animating the surface might not be destroyed until
the animation is completed and a reference to it kept around by gjs in the shell
case. By the way, per commit 7718e67f all window actors (even the animating
ones) are destroyed before the display is closed, but this is not true for the
child surface, because the parent window will just unref it, leaving it around
if reffed somewhere else. This is fine for wayland surfaces, but not for X11
ones which are bound to server-side pixmaps.
So, connect to the parent MetaWindowActor "destroy" signal, releasing the x11
resources that implies detaching the pixmap (unsetting the texture) and removing
the damages.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/629https://gitlab.gnome.org/GNOME/mutter/merge_requests/660
free_damage and detach_pixmap functions are called inside dispose and an object
can be disposed multiple times, even when the display is already closed.
So, don't try to deference a possibly null-pointer, assigning the xdisplay too
early, as if the X11 related resources have been unset, the server might not be
open anymore. In fact, we assume that if we have a damage or a pixmap set,
the display is still open.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/660
In MetaWindowActor creation we're setting the compositor private (i.e. the
window actor itself) of a window before creating the surface actor, and so
passing to the it a window without its compositor side set.
Since the surface actor might use the parent actor, set this before updating
the surface.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/660
As per commit 80e3c1d set_surface_actor has been added, meant to do different
things depending on the backend, like connecting to signals under X11.
However, the vfunc isn't ever used, making the X11 surfaces not to react to
repaint-scheduled signal.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/660
Everytime the top window changes we connect/disconnect to the actor's destroy
signal, although as explained in commit ba8f5a11 this might be slower in case
the window actor has many other signal connections.
So, just track this using an ID.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/660
The commit
commit 60f7ff3a69
Author: Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
Date: Fri Dec 21 18:12:49 2018 -0200
window-actor: Turn into a derivable class
made the previous instance struct a instance private struct, but didn't
remove the parent field. Since it's unused, there is no point in keeping
it around, so lets drop it.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/658
We're currently emitting the 'grab-op-end' signal when the grab prerequisites
are met, but when display->grab_op is still set to a not-NONE value and thus
meta_display_get_grab_op() would return that in the signal callback.
And more importantly when this is emitted, devices are still grabbed.
Instead, emit this signal as soon as we've unset all the grab properties and
released the devices.
Helps with https://gitlab.gnome.org/GNOME/gnome-shell/issues/1326https://gitlab.gnome.org/GNOME/mutter/merge_requests/596
Code underneath seems to handle errors properly, and this is apparently
here to save a few XSync()s on X11. Just drop this windowing dependent
bit to make things cleaner.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/420
When the compositor is destroyed we should cleanup the list of window actors we
created and destroy them.
Since all the actors are added to the window_group or top_window_group we can
just destroy these containers (together with the feedback_group), and simply
free the windows list.
This is particularly needed under X11 because before we destroy the display, we
might do some cleanups as detaching the surface pixmaps and freeing the damages
and if this happens at later point (for example when triggered by garbage
collector in gnome-shell), we might crash because the x11 dpy reference is
already gone.
Destroying the window actors instead, ensures we avoid any further call to X11
related functions and that we release the actors XServer resources.
Fixes https://gitlab.gnome.org/GNOME/mutter/issues/576
This reverts a change introduced in edfe5cc3 to use `paint_clipped_rectangle()`
instead of `cogl_framebuffer_draw_rectangle()` for full paints as it
contained logic necessary for viewport src-rects. This is not longer the case.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/504
This brings the viewport src-rect code in line with how we handle
transforms, by applying a `CoglMatrix` to the pipeline instead of
changing the paint logic.
It also fixes not-y-inverted textures in combination with
transforms.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/504
Commit 8e9184b6 added filtering to avoid image jaggies when downscaling
but used `LINEAR_MIPMAP_NEAREST`. In some situations this could lead to
GL choosing a single lower resolution mipmap and then upscaling it, hence
slightly blurry.
We don't want to revert that change since it avoids aliasing jaggies, so
let's use `LINEAR_MIPMAP_LINEAR` instead. This provides the highest quality
filtering that GL can do and avoids the situation of GL using a single
mipmap that's lower resolution than the screen. Now it will blend that one
with the next mipmap which is higher resolution than the screen. This still
avoids jaggies but also maintains 1px resolution.
Closes: https://gitlab.gnome.org/GNOME/gnome-shell/issues/1105https://gitlab.gnome.org/GNOME/mutter/merge_requests/505
When commit 91c6a144da synced shadows with Adwaita, it removed the
shadow completely from attached modal dialogs. However Adwaita uses
the same shadow for all dialogs (modal or not), so do the same here.
https://gitlab.gnome.org/GNOME/mutter/issues/490
We need to use pixel size of the monitor in order to generate a valid
texture with full quality for current monitor
In spanned case the background should cover all the differently scaled monitors
thus we scale the texture up to the maximum scaling level and then we resample
it drawing only each side in the monitor it should occupy using the proper
scaling level.
In wallpaper mode (or color mode) for example we don't need to scale the area,
also the texture size we return should be unscaled, not to confuse
MetaBackgroundActor making it use more space than needed.
https://bugzilla.gnome.org/show_bug.cgi?id=765011
To be used to translate absolute cursor positions to relative positions,
as well as to determine whether a cursor sprite is inside the stream or
not. It also helps calculating the scale the cursor sprite needs to be
scaled with to be in stream coordinate space.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/413
There are most likely no GNOME users left still using hardware that
does not support NPOT textures. Further more, they would crash much
earlier and never hit this code-path. So remove the unnecessary check
here.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/447
This implements the viewporter protocol which offers a cropping and scaling
capabilities to wayland clients.
There are several use cases for this, for example video players and games,
both as a convenience function and as potential performance optimization when
paired with hardware overlays etc.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/323
Commit 25f416c13d added additional compilation warnings, including
-Werror=return-type. There are several places where this results
in build failures if `g_assert_not_reached()` is disabled at compile
time and the compiler misses a return value.
https://gitlab.gnome.org/GNOME/mutter/issues/447
Make meson link libmutter using -fvisibility=hidden, and introduce META_EXPORT
and META_EXPORT_TEST defines to mark a symbols as visible.
The TEST version is meant to be used to flag symbols that are only used
internally by mutter tests, but that should not be considered public API.
This allows us to be more precise in selecting what is exported and what is
not, without the need of a version-script file that would be more complicated
to maintain.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/395
Previously, the clipping rectangle passed to
`meta_surface_actor_get_image()` was updated with the actual texture
size, but recent changes in `meta_shaped_texture_get_image()` now keep
the caller's clipping rectangle unchanged.
The implementation of `meta_window_actor_capture_into()` was relying on
the old behavior of updating the passed clipping rectangle, but now that
it's kept unchanged, the actual clipping rectangle used to copy the data
is wrong, which causes either a distorded image or worse, a crash of
mutter.
Use the resulting cairo image size to copy the data instead of the
clipping rectangle to avoid the issue and get the expected size.
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/442
I saw Meson fade from the sky
On the wind I heard a sigh
As snowflakes cover fallen Makefiles
I will say this last goodbye
Meson is now coming
So ends Autotools days
Future is now coming
And we must away
Over Python and without Bashisms
Through lands where never Meson touched
By silver streams that run down to the Sea
Under parsers, beneath old legacy
Over snow one winter’s morn
I turned at last to paths that lead home
And though where the road then takes me
I cannot tell
We came all this way
But now comes the day
To bid you farewell
Many places I have been
Many sorrows I have seen
But I don’t regret
Nor will I forget
All Makefiles that took that road with me
I bid you all a very fond farewell.
The texture tower can return no texture e.g. if the calculated level is
negative. This was handled before, but regressed with
e1370ee209. This fixes a potential crash
observed occasionally when starting Firefox nightly using the Wayland
backend in overview mode.
Now that everything is settled, from the initialization
process to the subclasses to moving code to the compositor,
MetaWindowActor can be a proper abstract class that cannot
be instantiated.
Thus, make MetaWindowActor an abstract class.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/368
This vfunc was added as a was to work around the convoluted
initialization process. Now that we figured it out and moved
the MetaWindowActor-specific initialization to constructed(),
we can override that.
Remove post_init() and use GObject.constructed() entirely.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/368
MetaWindowActor breaks layering isolation by accessing
and injecting itself into compositor->windows. This is
a bad practice, and effecticely makes returning the
new actor useless, since we doesn't even use the return
value.
Move window actor creation to under MetaCompositor and
stop violating (too badly) the resposabilities of each
component. This moves meta_window_actor_new() into
meta_compositor_add_window().
Also, move the remaining initialization code to the
GObject.constructed vfunc.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/368
Document the roles of MetaSurfaceActor and MetaWindowActor,
and when their subclasses are used.
(And this is actually the first real documentation under
src/compositor/README!)
https://gitlab.gnome.org/GNOME/mutter/merge_requests/368
MetaWindowActor handles sending _NET_WM_FRAME_* X atoms to
clients - even pure Wayland clients.
Now that we have Wayland- and X11-specific implementations of
MetaWindowActor, we can delegate this to MetaWindowActorX11,
and allow pure Wayland apps to not even connect to
MetaSurfaceActor:repaint-scheduled.
Do that by moving all the X11-specific code to the X11-specific
MetaWindowActorX11 class. Add vfuncs to MetaWindowActorClass
that are necessary for the move, namely:
* pre_paint() and post_paint()
* post_init()
* frame_complete()
* set_surface_actor()
* queue_frame_drawn()
https://gitlab.gnome.org/GNOME/mutter/merge_requests/368
Those are stub specialized classes for MetaWindowActor. This will
help ensuring that we do not execute X11-specific code paths on
pure Wayland clients.
The relationship between the window actor and the surface is the
following:
* Wayland: MetaWindowActorWayland + MetaSurfaceActorWayland
* X11: MetaWindowActorX11 + MetaSurfaceActorX11
* Xwayland: MetaWindowActorX11 + MetaSurfaceActorWayland
It is not possible to have MetaWindowActorWayland backed by a
MetaSurfaceActorX11 surface.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/368
We will introduce specialized MetaWindowActors for X11
and Wayland in the future, so it needs to be derivable.
Make it a derivable class, and introduce a private field.
The MetaWindowActorClass definition is in the private
header in order to prevent external consumers of Mutter
to create MetaWindowActor implementations of their own.
That is, MetaWindowActor is only internally derivable.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/368
EGLStream textures are imported as GL_TEXTURE_EXTERNAL_OES and reading
pixels directly from them is not supported. To make it possible to get
pixels, create an offscreen framebuffer and paint the actor to it, then
read pixels from the framebuffer instead of the texture directly.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/362
When a texture is transformed in any way (e.g. Wayland buffer
transforms), we cannot just fetch the pixels from the texture directly
and be done with it, as that will result in getting the untransformed
pixels.
To properly get the pixels in their right form, first draw to an
offscreen framebuffer, using the same method as when painting on the
stage, then read from the framebuffer into a cairo image surface.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/362
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/408
Implements the `MetaScreenCastWindow` interface for screen-cast
`RecordWindow` mode.
`meta_window_actor_capture_into()` implementation is still pretty crude
and doesn't take into account subsurfaces and O-R windows so menus,
popups and other tooltips won't show in the capture.
This is left as a future improvement for now.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/306
The shader used for computing a vignette currently has two
problems:
* The math is wrong such that the vignette isn't stretched
across the whole actor and so ends abruptly
* There is noticeable banding in its gradient
This commit corrects both problems by fixing the computing
and introducing noise dithering.
This adds the necessary bits to support Wayland buffer transforms.
The main part here is to properly setup the Cogl pipeline
and to recalculate the size of the painted area accordingly,
so culling etc. still works.
The choosen approach additionally lays groundwork for Wayland
wp_viewporter support.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/322
It cuts out some of the GObject boilerplate, and gives us g_autoptr()
support for free.
Since this changes the ABI, we also need to bump the libmutter API
version.
Following up last commit, this commit adds a CoglFramebuffer
argument to meta_shadow_paint(), and stops using the draw
framebuffer internally.
The only consumer of this API, MetaWindowActor, still passes
the draw framebuffer though.
MetaShadow.paint() uses Cogl implicit APIs (cogl_rectangle* ones, in
this case) to paint shadows with the shadow pipeline.
Replace those calls by cogl_framebuffer_draw_textured_rectangle()
calls, that achieve the exact same result but with the non-deprecated
API.
This commit adds meson build support to mutter. It takes a step away
from the three separate code bases with three different autotools setups
into a single meson build system. There are still places that can be
unified better, for example by removing various "config.h" style files
from cogl and clutter, centralizing debug C flags and other configurable
macros, and similar artifacts that are there only because they were once
separate code bases.
There are some differences between the autotools setup and the new
meson. Here are a few:
The meson setup doesn't generate wrapper scripts for various cogl and
clutter test cases. What these tests did was more or less generate a
tiny script that called an executable with a test name as the argument.
To run particular tests, just run the test executable with the name of
the test as the argument.
The meson setup doesn't install test files anymore. The autotools test
suite was designed towards working with installed tests, but it didn't
really still, and now with meson, it doesn't install anything at all,
but instead makes sure that everything runs with the uninstalled input
files, binaries and libraries when running the test suite. Installable
tests may come later.
Tests from cogl, clutter and mutter are run on 'meson test'. In
autotools, only cogl and clutter tests were run on 'make check'.
Install include files in
$prefix/include/mutter-$apiversion/[clutter,cogl,...,meta]/, and
datafiles in /usr/share/mutter-$apiversion/.... We still would conflict
e.g. given that our gettext name is "mutter", and how keybindings are
installed, but it's a step in the right direction.
This is the filename convention you get when you define a shared module
in meson, and since there is no particular reason to not include the
"lib" prefix, lets make it easier to port it over. While at it,
de-duplicate the retrieval of the plugin name.
The order and way include macros were structured was chaotic, with no
real common thread between files. Try to tidy up the mess with some
common scheme, to make things look less messy.
The clip and opaque region are both in a translated stage coordinate
space, where the origin is in the top left corner of the painted
texture. The painting, however, is in the texture coordinate space,
so when the texture is scaled, the coordinate spaces differ.
Handle this by transforming the clip and opaque region to texture
coordinate space before computing the blend region and the opaque region
to paint.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/300
They were int before entering MetaShapedTexture, used as ints in the
cairo regions and rectangles, so there is no reason they should be
stored as unsigned.
Related: https://gitlab.gnome.org/GNOME/mutter/issues/300
The compositor will automatically unredirect the top most window which
is fully visible on screen. When unredirecting windows, it also shapes
the compositor overlay window (COW) so that other redirected windows
still shows correctly.
The function `get_top_visible_window_actor()` however will simply walks
down the window list, so if a window is placed on a layer above and
unredirected, then iconified by the client, it will still be picked up
by `get_top_visible_window_actor()` and he compositor will reckon it's
still unredirected while not in a visible state anymore, thus leaving a
black area on screen.
Make sure we skip the windows not known to the compositor while picking
the top visible window actor to avoid this issue.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/306
The function is intentionally provided as macro to not require a
cast. Recently the macro was improved to check that the passed in
pointer matches the free function, so the cast to GDestroyNotify
is now even harmful.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/176
The special ::pick implementation there makes clutter fall into paths
that do require a get_paint_volume() implementation, or an infinite
area will be used.
Providing a paint volume here is easier on the invalidation mechanism.
This optimization was presumably added before Clutter was able to
invalidate selected regions of an actor. Paint volumes are supposed
to be invariable as long as the actor conditions don't change.
Stacking of other actors shouldn't affect the paint volume, so it's
actually wrong to optimize those areas away here.
- Stop using CurrentTime, introduce META_CURRENT_TIME
- Use g_get_monotonic_time () instead of relying on an
X server running and making roundtrip to it
https://bugzilla.gnome.org/show_bug.cgi?id=759538
Split X11 specific parts into MetaX11Display. This also required
changing MetaScreen to stop listening to any signals by itself, but
instead relying on MetaDisplay forwarding them. This was to ensure the
ordering. MetaDisplay listens to both the internal and external
monitors-changed signal so that it can pass the external one via the
redundant MetaDisplay(prev MetaScreen)::monitors-changed.
https://bugzilla.gnome.org/show_bug.cgi?id=759538
They are X11 specific functions, used for X11 code. They have been
improved per jadahl's suggestion to use gdk_x11_lookup_xdisplay and
gdk_x11_display_error_trap_* functions, instead of current code.
https://bugzilla.gnome.org/show_bug.cgi?id=759538
- Moved xdisplay, name and various atoms from MetaDisplay
- Moved xroot, screen_name, default_depth and default_xvisual
from MetaScreen
- Moved some X11 specific functions from screen.c and display.c
to meta-x11-display.c
https://bugzilla.gnome.org/show_bug.cgi?id=759538
This avoids overwhelming the GPU with trying to update mipmaps at a high
rate. Because doing so could easily cause a reduction in the compositor
frame rate and thus actually reduce visual quality.
In the case of a window that is constantly animating in the overview,
this reduces mutter's render time by around 20%-30%.
While MetaStage, MetaWindowGroup and MetaDBusDisplayConfigSkeleton don't
appear explicitly in the public API, their gtypes are still exposed via
meta_get_stage_for_screen(), meta_get_*window_group_for_screen() and
MetaMonitorManager's parent type. Newer versions of gjs will warn about
undefined properties if it encounters a gtype without introspection
information, so expose those types to shut up the warnings.
https://bugzilla.gnome.org/show_bug.cgi?id=781471
When using plugins, the effects will affect the MetaWindowActor size
and position.
Add a new signal "effects-completed" wired to the corresponding
MetaWindowActor which is emitted when all effects are completed so that
derived objects can be notified when all effects are completed and use
the actual size and position.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/104
Make the Wayland objects push the state relevant to their role to the
MetaSurfaceActor instead of MetaSurfaceActorWayland pulling the state
from the associated surface.
This makes the relationship between the actor and the objects that
constructs it more clear; the actor is a drawable that the protocol
objects control, not the other way around.
This will make it easier to "detach" a surface actor from a surface,
which is necessary when unmapping a window while the underlying surface
is yet to be destroyed and potentially reused.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/5https://bugzilla.gnome.org/show_bug.cgi?id=791938
When the top window actor is destroyed, we need to make sure that
all its references are removed or it could be picked again in next
windows sync, causing crashes.
Since the window might or might not be destroyed when removed (depending
weather animations are in progress over it or not), it's just safer
to wait it to be destroyed before cleaning up any of its reference.
https://bugzilla.gnome.org/show_bug.cgi?id=791006
We must emit ::dnd-leave to pair the ::dnd-enter that shall be
emitted whenever the plugin grab begins, otherwise we leave
listeners unable to clean up if the plugin begins and ends a
grab while there is an ongoing DnD operation.
https://bugzilla.gnome.org/show_bug.cgi?id=784545
This is not a leak per se, but it seems too easy to make valgrind
SIGSEGV due to MetaBackground disconnecting signals from an already
destroyed MetaScreen when trying to SIGTERM gnome-shell. Keeping a
reference fixes this.
https://bugzilla.gnome.org/show_bug.cgi?id=789984
It looks that there are some extensions that run a Mainloop on startup,
causing to dispatch a clutter paint before the compositor is even available.
In such scenario a MetaWindow could try to start a simple effect
using a compositor plugin which is not there yet.
Then in order to catch these bugs we can now assert that the expected
conditions are valid, so that gnome-shell will provide a dumpstack to
debug the real offending JS code.
https://bugzilla.gnome.org/show_bug.cgi?id=789223
There are cases when no compositor is available (yet) but a MetaWindow tries
to start a simple effect using a compositor plugin which is not available.
In that case we should just ignore any request and protect ourselves from
crashes.
https://bugzilla.gnome.org/show_bug.cgi?id=789223
This function might be called by components with invalid plugin manager
(as it might happen to MetaWindow when the compositor isn't initialized
properly), so we need to protect ourselves from crashes.
https://bugzilla.gnome.org/show_bug.cgi?id=789223
When determining whether we should unredirect a window or not, ignore
offscreen windows, and just check the top most visible window.
Previously this was not an issue, but since 'stack-tracker: Keep
override redirect windows on top' we started sorting the UI frames
window, which is an offscreen override redirect window, on top, causing
the unredirect checking code to always check whether to unredirect the
UI frames window. This effectively disabled the compositor bypass
functionality.
https://bugzilla.gnome.org/show_bug.cgi?id=788493
Turn MetaOutput into a GObject and move it to a separate file. This
changes the storage format, resulting in changing the API for accessing
MetaOutputs from using an array, to using a GList.
https://bugzilla.gnome.org/show_bug.cgi?id=785381
