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
Typically, to stream the content of a window, we need a way to copy the
content of its window-actor into a buffer, transform relative input
coordinates to relative position within the window-actor and a mean to
get the window bounds within the buffer.
For this purpose, add a new GType interface `MetaScreenCastWindow` with
the methods needed for screen-cast window mode:
* meta_screen_cast_window_get_buffer_bounds()
* meta_screen_cast_window_get_frame_bounds()
* meta_screen_cast_window_transform_relative_position()
* meta_screen_cast_window_capture_into()
This interface is meant to be implemented by `MetaWindowActor` which has
access to all the necessary bits to implement them.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/306
To be able to cast windows, which by definition can change in size
dynamically, we need a way to specify the video crop meta to adjust to
the window size whenever it changes.
Add VideoCrop support with a new optional hook `get_videocrop()` in the
`ScreenCastStreamSrcClass` which, if defined, can let the child specify
a rectangle for the video cropping area.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/306
Switch-configs are only to be used in certain circumstances (see
meta_monitor_manager_can_switch_config()) so when ensuring
configuration and attempting to create a linear configuration, use the
linear configuration constructor function directly without going via the
switch config method, otherwise we might incorrectly fall back to the
fallback configuration (only enable primary monitor).
This is a regression introduced by 6267732bec.
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/342
Which eliminates the 1px jitter that was visible when dragging windows,
and eliminates the flickering that was visible when pushing the cursor
against the right/bottom edges of the screen.
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.
If a display device (touchscreen, tablet with libwacom integration flags)
does not receive a monitor through settings. Delegate on the
MetaInputMapper so it receives a mapping through heuristics.
This object takes care of mapping absolute devices to monitors,
to do so it uses 3 heuristics, in this order of preference:
- If a device is known to be builtin, it's assigned to the
builtin monitor.
- If input device and monitor match sizes (with an error margin
of 5%)
- If input device name and monitor vendor/product in EDID match
somehow (from "full", through "partial", to just "vendor")
The most favorable outputs are then assigned to each device, making
sure not to assign two devices of the same kind to the same output.
This object replaces (and is mostly 1:1 with) GsdDeviceMapper in
g-s-d. That object would perform these same heuristics, and let
mutter indirectly know through settings changes. This object allows
doing the same in-process.
Since now we don't set the swap throttled value based
on sync-to-vblank, we can effectively remove it from
Cogl. Throttling swap buffers in Cogl is as much a
historical artifact as sync-to-vblank. Furthermore,
it doesn't make sense to disable it on a compositor,
which is the case with the embedded Cogl.
In addition to that, the winsys vfunc for updating
whenever swap throttling changes could also be removed,
since swap throttling is always enabled now.
Removing it means less code, less branches when running,
and one less config option to deal with.
This also removes the micro-perf test, since it doesn't
make sense for the case where Cogl is embedded into the
compositor.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/191
Externally setting the sync-to-vblank setting was a feature
added as a workaround to old Intel and ATI graphic cards, and
is not needed anymore. Furthermore, it doesn't make sense to
change it on a compositor whatsoever.
This commit removes all the ways to externally change this
setting, as well as the now unused API.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/191
The nested stage tries to emulate how CRTCs are drawn, but fails to do
this when a stage view is scaled as it didn't adapt the viewport size
according to the stage view scale.
https://bugzilla.gnome.org/show_bug.cgi?id=786663
Add MUTTER_DEBUG_DUMMY_MONITORS_SPECS env variable support so that you can define
a ':' separated list of monitor specs in the form of WWWxHHH@RR that will be
available for configuring the nested mutter.
When calculating the logical monitor layout size given a scale, don't
risk precision loss by float to int casting, which could result in a too
small layout.
https://bugzilla.gnome.org/show_bug.cgi?id=765011
Placing persistant Wayland popups (e.g. not menus etc) in the o-r layer
breaks stacking order with other window trees (e.g. other client
windows), as the menu would get stuck in the o-r layer, i.e. on top,
even if the parent of the popup got lowered.
Fix this by placing the popups in the normal layer, relying on
transient-ness to keep stacking correct.
When destructing a xdg_toplevel, we'll disassociate the actor from the
MetaWaylandSurface, to allow it to animate out. After having done this,
avoid trying to set it as unreactive when unsetting the window.
This fixes the runtime warning:
clutter_actor_set_reactive: assertion 'CLUTTER_IS_ACTOR (actor)' failed
Before processing the buffer damage region, intersect it with the buffer
rectangle to avoid trying to damage content outside the surface.
This fixes the runtime warning "GL error (1281): Invalid value"
happening when a client posts too large buffer damage larger.
We haven't supported disabling stage views in the native backend since
commit 70edc7dda4
Author: Jonas Ådahl <jadahl@gmail.com>
Date: Mon Jul 24 12:31:32 2017 +0800
backends/native: Stop supporting stage views being disabled
There were still some left over checks; lets remove them.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/343
This adds the required bits to wayland surfaces and ties them up
to the compositor parts.
The central part here is to recalculate the surface size accordingly
and to translate surface damage into buffer damage.
The choosen approach additionally lays groundwork for wp_viewporter
support, which is closely related in its nature.
A further explanation of buffer transforms from the specification:
> The purpose of this request is to allow clients to render content
> according to the output transform, thus permitting the compositor
> to use certain optimizations even if the display is rotated.
> Using hardware overlays and scanning out a client buffer for
> fullscreen surfaces are examples of such optimizations.
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
Commit 70036429bd mixed drag_origin and drag_surface, leading to warnings
and invisible drag icon. Fix this up so we correctly set up the feedback
actor. This will correctly display the DnD icon alongside the pointer.
It is meant to hold surfaces that require a ClutterActor, just like wl/xdg
shell surfaces and subsurfaces. Make it inherit from MetaWaylandActorSurface
so it gets that for free.
The type declaration is also made completely private, in order to avoid
cyclic dependency between meta-wayland-surface.h and
meta-wayland-actor-surface.h. We just require the GType fro assign_role()
anyway.
Modal ungrabs may be followed by other clients trying to grab themselves,
flush the connection so we ensure the right order of events on the Xserver
side.
An example of this is js/ui/modalDialog.js in gnome-shell, as the alt-F2
dialog may launch X11 clients trying to grab themselves, commit a40daa3c22
in gnome-shell handled the case and added a gdk_display_sync() call to
ensure no grab existed at the time of executing.
This commit aims to achieve the same built in MetaBackend. A full sync
seems excessive though, as we just need to make sure the server got the
messages queued before the other side tries to grab, a XFlush seems
sufficient for this.
The nested backend used the value from udev, meaning that one couldn't
configure the fake monitor if the laptop panel of the host was closed.
Avoid this annoyance by always having the nested backend claiming the
lid is open.
If meson tries to get ahead and generate object files for tests
at the same time than building libmutter, those may randomly fail
if meson did not create the libmutter generated headers yet.
Add those to the declared dependency, so the files are ensured to
be created before anything gets to use it.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/404
It wasn't implemented by any subclass, it's not provided by DRM either.
And even if a subclass were to have only a file available, it could read
it into a GBytes as well and just use `read_edid()`.
Found this while working on !269.
It's a UI pattern that has been superseded by client-side decorations,
apps that used to set the hint have generally moved on to headerbars.
Given that and the limitation to server-side decorated X11 windows,
GTK4 removed the client-side API for setting the hint, it's time to
follow suite and retire the feature.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/221
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.
Because it is implemented and always on. By advertising this fact
the master clock is able to sync to the native refresh rate instead
of always using the fallback of 60.00Hz.
https://bugzilla.gnome.org/show_bug.cgi?id=781296
Add support for getting hardware presentation times from KMS (Wayland
sessions). Also implement cogl_get_clock_time which is required to compare
and judge the age of presentation timestamps.
For single monitor systems this is straightforward. For multi-monitor
systems though we have to choose a display to sync to. The compositor
already partially solves this for us in the case of only one display
updating because it will only use the subset of monitors that are
changing. In the case of multiple monitors consuming the same frame
concurrently however, we choose the fastest one (in use at the time).
Note however that we also need !73 to land in order to fully realize
multiple monitors running at full speed.
Use cogl_framebuffer_read_pixels_into_bitmap () instead of
glReadPixels () for the CPU copy path in multi-GPU support.
The cogl function employs several tricks to make the read-pixels as fast
as possible and does the y-flip as necessary. This should make the copy
more performant over all kinds of hardware.
This is expected to be used on virtual outputs (e.g. DisplayLink USB
docks and monitors) foremost, where the dumb buffer memory is just
regular system memory. If the dumb buffer memory is somehow slow, like
residing in discrete VRAM or having an unexpected caching mode, it may
be possible for the cogl function perform worse because it might do the
y-flip in-place in the dumb buffer. Hopefully that does not happen in
any practical scenario.
Calling meta_renderer_native_gles3_read_pixels () here was conceptually
wrong to begin with because it was done with the Cogl GL context of the
primary GPU, not on the GL ES 3 context of a secondary GPU. However,
due eglBindAPI being a no-op in Mesa and the glReadPixels () arguments
being compatible, it worked.
This patch adds a pixel format conversion table between DRM and Cogl
formats. It contains more formats than absolutely necessary and the
texture components field which is currently unused for completeness. See
Mutter issue #323. Making the table more complete documents better how
the pixel formats actually map so that posterity should be less likely
to be confused. This table could be shared with
shm_buffer_get_cogl_pixel_format () as well, but not with
meta_wayland_dma_buf_buffer_attach ().
On HP ProBook 4520s laptop (Mesa DRI Intel(R) Ironlake Mobile, Mesa
18.0.5), without this patch copy_shared_framebuffer_cpu () for a
DisplayLink output takes 5 seconds with a 1080p frame. Obviously that
makes Mutter and gnome-shell completely unusable. With this patch, that
function takes 13-18 ms which makes it usable if not fluent.
On Intel i7-4790 (Mesa DRI Intel(R) Haswell Desktop) machine, this patch
makes no significant difference (the copy takes 4-5 ms).
The format will be needed in a following commit in the CPU copy path
which stops hardcoding another format and starts using the format the
dumb FB was created with.
Change the callers of init_dumb_fb () to use DRM format codes. DRM and
GBM format codes are identical, but since this is about dumb buffers,
DRM formats fit better.
The header /usr/include/gbm.h installed by Mesa says:
* The FourCC format codes are taken from the drm_fourcc.h definition, and
* re-namespaced. New GBM formats must not be added, unless they are
* identical ports from drm_fourcc.
That refers to the GBM_FORMAT_* codes.
Virtual keyboard and pointer are freed on session close, but the
virtual touchscreen isn't.
Avoid a leak by freeing the virtual touchscreen along with the rest of
virtual devices.
We were using the connector_id for the winsys_id, but different
devices could have connectors with the same id. Since we use
winsys_id to uniquely identify outputs, use both the connector
id and the device id to avoid having outputs with the same id.
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.
Python is not guaranteed to be installed in /usr/bin. This is especially
true for *BSD systems which don't consider Python as an integral part of
their systems.
We already ran a Wayland client to test various Wayland paths. What was
missing to also run a X11 client was to hook in the X11 async waiter
wires, so do that and run both types of clients.
https://bugzilla.gnome.org/show_bug.cgi?id=790207
As with the Wayland display name, to avoid clashes with already an
running Xwayland or Xorg instance, override the X11 display name to
something less likely to cause a clash.
https://gitlab.gnome.org/GNOME/mutter/issues/193
For Wayland outputs, we do not expose the actual transformation because
mutter does not support wl_surface.set_buffer_transform yet, instead we
swap the logical width and height when the output is rotated.
However, a client wishing to use the physical size would get confused,
so if the output is rotated, rotate the physical dimensions as well for
consistency.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/369
Moving windows using `move-to-side-X` and `move-corner-XX` keybindings
should keep windows within the confines of current screen.
`move-to-monitor-XXX` keybindings can be used to move windows to other
monitors.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/320
Commit 8d3e05305 ("window: Force update monitor on hot plugs") added the
flag `META_WINDOW_UPDATE_MONITOR_FLAGS_FORCE` passed to
`update_monitor()` from `update_for_monitors_changed()`.
However, `update_for_monitors_changed()` may choose to call another code
path to `move_between_rects()` and `meta_window_move_resize_internal()`
eventually.
As `meta_window_move_resize_internal()` does not use the "force" flag,
we may still end up in case where the window->monitor is left unchanged.
To avoid that problem, add a new `MetaMoveResizeFlags` that
`update_for_monitors_changed()` can use to force the monitor update from
`meta_window_move_resize_internal()`.
Fixes: 8d3e05305 ("window: Force update monitor on hot plugs")
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/189
Don't schedule redraws when being headless; there is nothing to draw so
don't attempt to draw. This also makes a flaky test become non-flaky, as
it previously spuriously got warnings due to windows being "painted"
when headless but lacking frame timings, as nothing was actually
painted.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/170
The empty MetaStage was in meta-stage-private.h for no reason, so lets
move it to the C file. This makes it pointless to have a private
instance struct, so just move the fields to the private struct
_MetaStage.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/170
Instead of using gtk_css_provider_get_default(), add a
static GtkCssProvider and fetch it instead. Creating
GtkCssProviders consume a bit more memory, so keeping
a single one alive is slightly more memory saving.
It relied on indices in arrays determining tile direction and
non-obvious bitmask logic to translate to _GTK_EDGE_CONSTRAINTS. Change
this to explicitly named edge constraints, and clear translation methods
that converts between mutters and GTK+s edge constraint formats.
An unnecessary memory optimization, storing the tile mode as a 2 bit
unsigned integer, was used. While saving a few bytes, it made debugging
harder. Remove the useless byte packing.
Meson uses the 'dependencies' field to determine and
parallelize build steps, but that isn't entirely true
with 'link_with'; this might cause a race condition
when generating header files while trying to build
them.
Fix that by only using 'dependencies' instead of 'link_with'.
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'.
The touch handling code uses evdev API, thus will not work on other
backends. Thus, put touch handling code behind runtime backend checks
and only include the code when native backend support is enabled.
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.
It'll be installed in the meta/ directory, so put the template files in
the corresponding directory in the tarball. This will also simplify the
port to meson.
While leaving the runtime checks in place, requiring xrandr 1.5 at build
time allows us to remove some seemingly unnecessary conditional
inclusion of functionality.
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.
testboxes was a binary that did unit testing, but it wasn't integrated
to the test system, so in effect, it was never run. Instead integrate it
into the other mutter unit tests. This includes changing a few of
meta_warning()s into g_warning()s so that the GTest framework can handle
them.
Closing a GdkDisplay during an event handler is not currently supported by Gdk
and it will result in a crash when doing e.g. 'mutter --replace'. Using an idle
function will close it safely in a subsequent main loop iteration.
Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/issues/595
meta_workspace_manager_override_workspace_layout is implemented by
calling meta_workspace_manager_update_workspace_layout which
respects the workspace_layout_overridden flag. After the first call
to meta_workspace_manager_override_workspace_layout all subsequent
calls fail silently.
Reset workspace_layout_overridden to FALSE before calling
meta_workspace_manager_update_workspace_layout.
https://gitlab.gnome.org/GNOME/mutter/issues/270
drmModePageFlip() is guaranteed to fail for the invalid FB id 0.
Therefore it never makes sense to call this function with such argument.
Disabling a CRTC must be done with SetCrtc instead, for example.
Trying to flip to FB 0 not only fails, but it also causes Mutter to
never try page flip on this output again, using drmModeSetCrtc()
instead.
There was a race in setting next_fb_id when a secondary GPU was using
the CPU copy path. Losing this race caused the attempt to
drmModePageFlip () to FB ID 0 which is invalid and always fails. Failing
to flip causes Mutter to fall back to drmModeSetCrtc () permanently.
In meta_onscreen_native_swap_buffers_with_damage ():
- update_secondary_gpu_state_pre_swap_buffers ()
- copy_shared_framebuffer_cpu () but only on the CPU copy path
- secondary_gpu_state->gbm.next_fb_id is set
- wait_for_pending_flips ()
- Waits for any remaining page flip events and executes and destroys
the related page flip closures.
- on_crtc_flipped ()
- meta_onscreen_native_swap_drm_fb ()
- swap_secondary_drm_fb ()
- secondary_gpu_state->gbm.next_fb_id = 0;
- meta_onscreen_native_flip_crtcs ()
- meta_onscreen_native_flip_crtc ()
- meta_gpu_kms_flip_crtc () gets called with fb_id = 0
This race was observed lost when running 'mutter --wayland' on a machine
with two outputs on Intel and one output on DisplayLink USB dock, and
wiggling around a weston-terminal window between the Intel and
DisplayLink outputs. It took from a second to a minute to trigger. For
testing with DisplayLink outputs Mutter also needed a patch to take the
DisplayLink output into use, as it would have otherwise been ignored
being a platform device rather than a PCI device.
Fix this race by first waiting for pending flips and only then
proceeding with the swap operations. This should be safe, because the
pending flips could have completed already before entering
meta_onscreen_native_swap_buffers_with_damage ().
We might unset focus, or already be out of focus (e.g. an X11 client or
clutter text entry is focused) when a text-input state is committed by
the client. We handled this before, except when text input was
explicitly disabled by the client, the Wayland text-input was in focus
by the input method, and it focused itself out.
Simplify the logic a bit by just dropping the state on the floor in all
cases where after any potential focus changes were done, we are not
focused.
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/353
Commit 840378ae68 changed the code to use XmbTextPropertyToTextList()
instead of gdk_text_property_to_utf8_list_for_display(), but didn't
take into account that the replacement returns text in the current
locale's encoding, while any callers (rightfully) expect UTF8.
Fix this by converting the text if necessary.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/227
The WM_NAME property is of type TEXT_PROPERTY, which is supposed to be
returned as UTF-8. Commit 840378ae68 broke that assumption, resulting
in crashes with non-UTF8 locales; however the "fix" of converting from
LATIN1 to UTF8 is wrong as well, as the conversion will spit out garbage
when the input encoding isn't actually LATIN1.
Now that the original issue in text_property_to_utf8() has been fixed,
we can simply revert the relevant bits of commit d62491f46e.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/227
In order to allow a window with a custom rule placement to be moved
together with its parent, the final rule used derived from the
constraining were used for subsequent constraints. This was not enough
as some constraining cannot be translated into a rule, such as sliding
across some axis.
Instead, make it a bit simpler and just remember the position relative
to the parent window, and use that the next time.
This is a rework of 5376c31a33 which
caused the unwanted side effects.
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/332
When constructing MetaMonitorsConfig objects, store which type
of switch_config they are for (or UNKNOWN if it is not such
type of config).
Stop unconditionally setting current_switch_config to UNKNOWN when
handling monitors changed events. Instead, set it to the switch_config
type stored in the MonitorsConfig in the codepath that updates logical
state. In addition to being called in the hotplug case along the same
code flow that generates monitors changed events, this is also called
in the coldplug case where a secondary monitor was connected before
mutter was started.
When creating the default linear display config, create it as a
switch_config so that internal state gets updated to represent
linear mode when this config is used.
The previous behaviour of unconditionally resetting current_switch_config
to UNKNOWN was breaking the internal state machine for display config
switching, causing misbehaviour in gnome-shell's switchMonitor UI when
using display switch hotkeys. The lack of internal tracking when the
displays are already in the default "Join Displays" linear mode was
then causing the first display switch hotkey press to do nothing
(it would attempt to select "Join Displays" mode, but that was already
active).
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/281https://gitlab.gnome.org/GNOME/mutter/merge_requests/213
When repicking after a surface was destroyed, if the destroyed surface
was the drag focus, we'd try to focus-out from it after it was
destroyed, causing a NULL pointer dereference.
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/336
With Wayland, a window is not showing until it's shown. Until this
patch, the initial state of MetaWindow, on the other hand, was that a
window is initialized as showing. This means that for a window to
actually be classified as shown (MetaWindow::hidden set to FALSE),
something would first have to hide it.
Normally, this wasn't an issue, as normally we'd first create a window,
determine it shouldn't be visible (due to missing buffer), hide it
before the next paint, then eventually show it. This doesn't work if
mutter isn't drawing any frames at the moment (e.g. the user switched
VT), as we'd miss the hiding before showing as e result of a buffer
being attached. The most visible side effect is that a window can't be
moved as the window actor remains frozen.
This commit fixes this issue by correctly classifying a newly created
Wayland window as "hidden".
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/331
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
