The propagation phase property/methods in GtkEventController are gone,
This is now set directly on the GtkWidget add/remove controller API,
which has been made private.
The only public bit now are the new functions gtk_gesture_attach() and
gtk_gesture_detach() that will use the private API underneath.
All callers have been updated.
Within a widget, if a gesture accepts a sequence, it would previously
cancel every other gesture that not in the same group. Change this to
only cancelling gestures that previously claimed the gesture, and let
gestures with state=NONE for that sequence remain like that.
This enables late recognition of gestures, even on the presence of
another gesture group that was more eager at claiming the gesture.
One usecase is user-defined panning gestures on scrolledwindows,
if ::capture-button-press is TRUE (eg. the default), the gesture is
claimed early in order to consume the button press, but that would
tipically make every other gesture group deny the sequence. With
this change, the pan gesture can keep state=NONE, and later claim
the sequence for itself if the panning gesture is recognized.
Also, do not propagate state=DENIED to every gesture in the widget,
that was unintended.
The utility of those signals is somewhat dubious now that there is
gtk_gesture_group(), so make that the only way to coordinate gestures.
The cooperation model offered by gtk_gesture_group() is flexible
enough,
Listen for notify::sequence-state-changed on the controller, so the
only way to manipulate a sequence state are gtk_gesture_set_sequence_state()
and gtk_gesture_set_state().
Also, make use of gesture groups, so the sequence state is set at once
on all gestures pertaining to a single group. Within a widget, if a sequence
is claimed on one group, it is made to be denied on every other group.
GtkEventController may be certainly useful to keep event
handling self-contained in other places than gestures, but
the current widget API is highly related to gestures, so
just using GtkGesture as the argument there will be quite
more convenient. The other places where GtkEventController
make sense as a base object will better provide their own
hooks.
Gestures attached with this phase will expect callers to have it
receive events through gtk_event_controller_handle_event(), but
the gesture will still be notified of sequence state changes,
grabs, etc...
If the captured touch begin or button press event have been consumed
for the given sequence, propagate it upwards if the sequence goes from
claimed to denied, so the widgets on the way to the event widget receive
a coherent event stream now that they're going to receive events.
The policy of sequence states has been made tighter on GtkGesture,
so gestures can never return to a "none" state, nor get out of a
"denied" state, a "claimed" sequence can go "denied" though.
The helper API at the widget level will first emit
GtkWidget::sequence-state-changed on the called widget, and then
notify through the same signal to every other widget in the captured
event chain. So the effect of that signal is twofold, on one hand
it lets the original widget set the state on its attached controllers,
and on the other hand it lets the other widgets freely adapt to the
sequence state changing elsewhere in the event widget chain.
By default, that signal updates every controller on the first usecase,
and propagates the default gesture policy to every other widget in the
chain on the second. This means that, by default:
1) Sequences start out on the "none" state, and get propagated through
all the event widget chain.
2) If a widget in the chain denies the sequence, all other widgets are
unaffected.
3) If a widget in the chain claims the sequence, then:
3.1) Every widget below the claiming widget (ie. towards the event widget)
will get the sequence cancelled.
3.2) Every widget above the claiming widget that had the sequence as "none"
will remain as such, if it was claimed it will go denied, but that should
rarely happen.
This behavior can be tweaked through the GtkWidget::sequence-state-changed and
GtkGesture::event-handled vmethods, although this should be very rarely done.
A controller can be optionally hooked on the capture or the bubble
phase, so the controller will automatically receive and handle events
as they arrive without further interaction.
Make the relative_to widget the parent for a GtkPopover's
GtkActionGroup. This, for example, makes the menu model of a
GtkMenuButton find action groups attached to the button.
https://bugzilla.gnome.org/show_bug.cgi?id=729915
The documentation for the GtkWidget::size-allocate signal is missing the
description of the "allocation" parameter. Add the missing description
to the parameter.
https://bugzilla.gnome.org/show_bug.cgi?id=726179
Add gdk_device_get_last_event_window(), and use to implement the window
tracking we need for synthesizing crossing events for sensitivity changes
and gtk grabs, rather than keeping the information in qdata and updating
it based when GTK+ gets events.
https://bugzilla.gnome.org/show_bug.cgi?id=726187
Try to do a better job of keeping example content
from being too wide. It is often rendered as <pre>
text so the only time we can wrap it is in the source.
It is best to full break lines at all punctuation and
to try to keep the width under 70 chars or so.
The properties are declared read-write, but only the setter
was hooked up. This was leading to criticals in test apps using
the prop-editor.c code. Complete the implementation by adding the
getter side too.
Previously we did a semi-successful job at ignoring it. Unfortunately
this job was bad enough that we could lose the direction.
We still allow passing in the enum values, because we want code like
this to work:
set_state_flags (get_state_flags() | SOME_FLAGS)
10b5ec20 made sure not to set focus_child to NULL all the way up to the
top, but only up to the common ancestor. However, it would never set it
on the common ancestor itself, which would therefore remain with a
focus_child set when it shouldn't.
A manifestation of the bug: focus column headers of a treeview, press Tab.
Now pressing Shift+Tab will go to another widget and not the column
headers, and Tab will (appear to) do nothing, all because the treeview
still has a focus_child set to column headers after a grab_focus().
Signed-off-by: Olivier Brunel <jjk@jjacky.com>
https://bugzilla.gnome.org/show_bug.cgi?id=723402
The root window is a fairly X-centric concept, and it
really has no place in the GtkWidget API. Plus, this
is a rarely-used one-line convenience function with
poor documentation.
Add margin-{start,end} and gtk_widget_{get,set}_margin_{start,end}
and drop margin-{left,right} and gtk_widget_{get,set}_margin_{left,right}.
margin-{start,end} handle right also in RTL.
https://bugzilla.gnome.org/show_bug.cgi?id=710238
_gtk_widget_draw_internal() was clipping by passing the subwindow
sizes as a path to cairo_clip(). This was breaking for windows
larger than 23 bits in width/height, due to cairo using fixed point
(24.8) for the path coordinates.
We fix this by pre-clipping the subwindow region to the existing
cairo clip region in the full 32bit gdkwindow precision. This fixes
the GooCanvas Large Items test.
https://bugzilla.gnome.org/show_bug.cgi?id=710958
For some widgets, like GtkTreeView, which setup a clock frame
update during realize, it was possible to call
gdk_frame_clock_begin_updating() twice, but only ever disconnecting
from it once. This happens because the realized flag is set at an
unpredictable time by the GtkWidget's realize implementation.
Keep the signal handler ID from us connecting to the "update" signal
to avoid connecting to it twice.
This fixes high wake-up count from any application using GtkTreeView,
even idle ones.
https://bugzilla.gnome.org/show_bug.cgi?id=710666
Previously, GtkWindow would add the "app" action group to its own
toplevel muxer.
Change the setup so that GtkApplication creates the toplevel muxer and
adds itself to it as "app". Use this muxer as the parent muxer of any
GtkWindow associated with the application.
This saves a small amount of memory and will allow for accels to be
propagated from the application through to all of the windows.
GtkWidget had a hack where if opacity is 0.999 we set up an opacity group when
rendering the widget. This is no longer needed in 3.10, and GtkStack doesn't
use it anymore.
GdStack is using it, so applications should be ported from GdStack to GtkStack
in 3.12.
https://bugzilla.gnome.org/show_bug.cgi?id=703603
Updated documentation to specify that '0' should be specified if
one does not need to automatically assign a bound child to a public
or private instance member (now that negative values are private
structure offsets).
* gtk/gtkwidget.c: drag-leave signal: Document that it is called before
drag-drop.
drag-data-received signal: Document that it is up to the application
to know why the data was requested (e.g. drag motion or drop).
* demos/gtk-demo/toolpalette.c: interactive_canvas_drag_drop():
Do not transform the drop_item created in the drag-motion handler.
Instead caused drag-data-received to be called, remembering why,
and create a new item there.
interactive_canvas_drag_leave(): Remove the idle-handler hack,
now that we do not need to keep the drag-motion drop_item alive until
the drop.
I noticed that this patch was sitting in bug #605611 from 2009
though it had been approved. I do not remember much about why I
created it.
This is the same behaviour as gtk_widget_get_valign, except
we have no gtk_wiget_get_halign_with_baseline, as baselines make
no sense for halign.
Without this some widgets (like e.g. GtkOverlay) crash if you accidentally
set a BASELINE halign.
We rename the gtk_widget_class_bind_template_child{_internal}
macros by appending a _private to their name. Otherwise, it
would be too magic to pass the 'public' names as arguments,
but affect a member of the Private struct. At the same time,
Add two new macros with the old names,
gtk_widget_class_bind_template_child{_internal} that operate
on members of the instance struct.
The macros and functions are inconsistently named, and are not tied to
the "template" concept - to the point that it seems plausible to use
them without setting the template.
The new naming scheme is as follows:
gtk_widget_class_bind_template_child_full
gtk_widget_class_bind_template_callback_full
With the convenience macros:
gtk_widget_class_bind_template_child
gtk_widget_class_bind_template_child_internal
gtk_widget_class_bind_template_callback
https://bugzilla.gnome.org/show_bug.cgi?id=700898https://bugzilla.gnome.org/show_bug.cgi?id=700896
Using an offset from the struct means you can have children in
both the public and private (via G_PRIVATE_OFFSET) parts of the
instance. It also matches the new private macros nicer.
https://bugzilla.gnome.org/show_bug.cgi?id=702563
Signed-off-by: Emmanuele Bassi <ebassi@gnome.org>
We've recently a number of classes wholly. For these cases,
move the headers and sources to gtk/deprecated/ and adjust
Makefiles and includes accordingly.
Affected classes:
GtkAction
GtkActionGroup
GtkActivatable
GtkIconFactory
GtkImageMenuItem
GtkRadioAction
GtkRecentAction
GtkStock
GtkToggleAction
GtkUIManager
Historically the following states propagated to children:
GTK_STATE_FLAG_ACTIVE
GTK_STATE_FLAG_PRELIGHT
GTK_STATE_FLAG_SELECTED
GTK_STATE_FLAG_INSENSITIVE
GTK_STATE_FLAG_INCONSISTENT
GTK_STATE_FLAG_BACKDROP
However, several of these are problematic on containers like GtkListBox.
For instance, if a row is ACTIVE or SELECTED then all children (like e.g
a button) inside the row will *also* look active/selected. This is almost
never right. The right way to theme this is to catch e.g. SELECTED on the
container itself and set e.g. the color and let the children inherit
the color instead of the flag.
We now propagate only these flags:
GTK_STATE_FLAG_INSENSITIVE
GTK_STATE_FLAG_BACKDROP
Which make sense to be recursive as they really affect every widget
inside the container.
However, this is a CSS theme break, and while most things continue working
as-is some themes may need minor tweaks.
Rename our internal GActionMuxer, GActionObserver and GActionObservable
classes and interfaces to have names in our own namespace.
These classes were originally intended for GIO but turned out to be too
special-purpose to be useful there, so we never made them public API but
have just been copying them around (without bothering to properly rename
them). Now that other people will be copying them out of Gtk, it's even
more important to prevent this namespace abuse from spreading further.
This makes iterating over the children a lot faster, as we're
not doing lots of intra-library calls and type checks. We're still
in some sence O(n^2) since we iterate over each child window for each
widget, but the profiles look much better.
Since widgets now cache drawn state we allow them to override
queue_draw_region to detect when some region of the widget
should be redrawn. For instance, if a widget draws the
background color in a pixel cache we will need to invalidate
that when the style context changes which queues a repaint.
We do the save/restore when emitting ::draw rather than in a custom
marshaller, as this saves an extra stack frame, which is helpfull now
that we do painting fully recursive. This is also likely to save a few
cycles.
We now consider non-native windows non-opaque, which means any invalid
area in a subwindow will also be invalid all the way up to the nearest
native windows. We take advantage of this by ignoring all expose events
on non-native windows (which typically means just the toplevel) and instead
propagating down the draw() calls to children directly via
gtk_container_propagate_draw.
This is nice as it means we always draw widgets the same way, and it
will let us do some interesting ways in the future.
We also clean up the GtkWidget opacity handling as we can now always
rely on the draing happening via cairo.
We can't really just draw by walking down the widget hierarchy, as
this doesn't get the clipping right (so e.g. widgets doing cairo_paint
may draw outside the expected gdkwindow subarea) nor does it let
us paint window backgrounds.
So, we now do multiple draws for each widget, once for each GdkWindow,
although we still do it on the same base cairo_t that we get for the
toplevel native window. The difference is only the clipping, the rendering
order, and which other widgets we propagate into.
We also collect all the windows of a widget so we can expose them inside
the same opacity group if needed.
NOTE: This change neuters gtk_widget_set_double_buffered for
widgets without native windows. Its impossible to disable
the double buffering in this model.
Pointed out in https://bugzilla.gnome.org/show_bug.cgi?id=699016
The fix here is slightly different. We make
_gtk_builder_parser_translate return a const char * instead of
a dup'ed string, and fix up the callers.
If a subclass (say a child of GtkButton) overrides the non-baseline
size request methods we need to call these, rather than the new
get_height_and_baseline_for_width method.
In order to handle this we make the default for this method to be
NULL, and instead check at runtime which method to call. If any
non-baseline vfunc has changed in a class but the baseline one
hasn't, then we can't use the baseline one.
This modifies the size machinery in order to allow baseline support.
We add a new widget vfunc get_preferred_height_and_baseline_for_width
which queries the normal height_for_width (or non-for-width if width
is -1) and additionally returns optional (-1 means "no baseline")
baselines for the minimal and natural heights.
We also add a new gtk_widget_size_allocate_with_baseline() which
baseline-aware containers can use to allocate children with a specific
baseline, either one inherited from the parent, or one introduced due
to requested baseline alignment in the container
itself. size_allocate_with_baseline() works just like a normal size
allocation, except the baseline gets recorded so that the child can
access it via gtk_widget_get_allocated_baseline() when it aligns
itself.
There are also adjust_baseline_request/allocation similar to the
allocation adjustment, and we extend the size request cache to also
store the baselines.
Setting this means baseline aware containers should align the widget
according to the baseline. For other containers this behaves like
FILL.
In order to not suprise old code with a new enum value we always
return _FILL for _BASELINE unless you specifically request it via
gtk_widget_get_valign_with_baseline().
This commit implements the needed machinery for GtkWidget
to build it's composite content from GtkBuilder XML and
adds the following API:
o gtk_widget_init_template()
An api to be called in instance initializers of any
GtkWidget subclass that uses template XML to build it's components.
o gtk_widget_class_set_template()
API to associate GtkBuilder XML to a given GtkWidget subclass
o gtk_widget_class_automate_child()
API to declare an object built by GtkBuilder to be associated
with an instance structure offset and automatically set.
o gtk_widget_get_automated_child()
API for bindings to fetch a child declared to be automated by
gtk_widget_class_automate_child(), for the case where bindings
do not generate GObjects under the hood and cannot use structure
offsets to resolve composite object pointers.
o gtk_widget_class_declare_callback[s]()
Declare static functions to be used in signal callbacks from
a given class's template XML
o gtk_widget_class_set_connect_func()
API for bindings to override the signal connection machinery
for a given GtkWidget derived class.
Deprecate gtk_widget_push_composite_child, gtk_widget_pop_composite_child,
gtk_widget_set_composite_name, gtk_widget_get_composite_name.
This API is just bloat and was never useful, this patch deprecates
it and removes all internal calls to the composite child APIs
Some functions in gtkstyle.h were overlooked when we added the
GDK_DEPRECATED macros.
Also add IGNORE_DEPRECATIONS to the few remaining callers of those
functions.
If the style changes before we're realized we will delay the
style-updated signal until realize. However, we then lose
the changes bitmap. This means that gtk_widget_real_style_updated()
must treat a NULL change as "everything changed" and queue a resize.
Both of them started to make use of round(), a C99 function. So, include
fallback-c89.c to provide a fallback implementation for round() for
compilers that don't have round()
https://bugzilla.gnome.org/show_bug.cgi?id=694339
The last change fixed the windowed widget case but broke
opacity group handling for windowed child widgets. This fixes
up the code by making sure we norender_children in when there
is an opacity group.
This also cleans up the comments about how this works to something
that is hopefully more understandable.
Add an API to start or stop continually updating the frame clock.
This is a slight convenience for applcations and avoids the problem
of getting one more frame run after an animation stops, but the
primary motivation for this is because it looks like we might have
to use timeBeginPeriod()/timeEndPeriod() on Windows to get reasonably
accurate timing, and for that we'll need to know if there is an
animation running.
https://bugzilla.gnome.org/show_bug.cgi?id=693934
We clear GtkTickCallbackInfo on creation to ensure all fields start
as 0. Before we sometimes ended up with destroyed being 1
so the tick was never called.
We need to disconnect the frame clock when we unrealize (at which
point the old clock is still alive) not in destroy(). Since there
is no common unrealize for containers, trigger this from GtkWidget.
Add a very simple GtkWidget function for an "tick" callback, which
is connected to the ::update signal of GdkFrameClock.
Remove:
- GtkTimeline. The consensus is that it is too complex.
- GdkPaintClockTarget. In the rare cases where tick callbacks
aren't sufficient, it's possible to track the
paint clock with ::realize/::unrealize/::hierarchy-changed.
GtkTimeline is kept using ::update directly to allow using a GtkTimeline
with a paint clock but no widget.
Switch GtkStyleContext to using GdkFrameClock. To do this, add a new
UPDATE phase to GdkFrameClock.
Add a GdkFrameClockTarget interface with a single set_clock() method,
and use this to deal with the fact that GtkWidget only has a frame
clock when realized.
https://bugzilla.gnome.org/show_bug.cgi?id=685460
Instead of having gdk_frame_clock_request_frame() have
gdk_frame_clock_request_phase() where we can say what phase we need.
This allows us to know if we get a frame-request during layout whether
it's just a request for drawing from the layout, or whether another
layout phase is needed.
https://bugzilla.gnome.org/show_bug.cgi?id=685460
This adds a way to get the gtk_widget_set_opacity liike behaviour
of retargeting GdkWindows and exposing every child in ::draw, without
actually having an alpha. This is needed if you're doing more complex things
such as cross fading of widgets.
We do this as a hack by using opacity values that round to 255 yet not
really 1.0 in order to avoid having some magical API call for this
mainly internal call.
https://bugzilla.gnome.org/show_bug.cgi?id=687842
This adds gtk_widget_get/set_opacity, as well as a GtkWidget.opacity
property. Additionally it deprectates gtk_window_get/set_opacity and
removes the GtkWindow.opacity property (in preference for the new
identical inherited property from GtkWidget, which should be ABI/API
compat).
The implementation is using the new gdk_window_set_opacity child
window support for windowed widgets, and cairo_push/pop_group()
bracketing in gtk_widget_draw() for non-window widgets.
https://bugzilla.gnome.org/show_bug.cgi?id=687842
This replaces the previously hardcoded calls to gdk_window_set_user_data,
and also lets us track which windows are a part of a widget. Old code
should continue working as is, but new features that require the
windows may not work perfectly.
We need this for the transparent widget support to work, as we need
to specially mark the windows of child widgets.
https://bugzilla.gnome.org/show_bug.cgi?id=687842
This is a quickfix to keep things working.
It turns out GtkWindow assumes it can do sizing operations while not
being visible, or while in the process of show()ing/hide()ing itself.
And commit b495ce54 broke these operations.
Figuring this properly requires some more thinking and restructuring on
my part, so for now we relax the requirement of visiblility enough for
these things to start working again.
GtkWidget::visible is required for the widget to:
- have a preferred size other than 0/0
- have a size allocated
- return other values than { -1, -1, 1, 1 } from get_allocation()
This is an experimental patch aiming to make concepts and behaviors
inside GTK more concreate. GtkWidget::visible is now essentially what
CSS does for "display: none".
Note that if you want the effect of CSS's "visibility: hidden", you'll
have to use a GtkNotebook with an empty page as the concept of reserving
space but not drawing anything isn't supported natively in GTK.
Previously, with STATE_FLAGS_REPLACE we would unset _all_ the state
flags on children, not just the ones that do propagate. This caused the
RTL/LTR flags to get lost.
Now that Pango tracks changes to the context automatically there is
no need to do it manually in e.g. style-updated or direction-changed,
in fact the only case we have to care about is when we re-create
the PangoContext due to a screen change, so we only have to clear
the layouts in GtkLabel in screen-changed.
This means we're not clearing all the layouts whenever the state changes,
which happens to every widget when the window is unfocused, which helps
performance a lot.
https://bugzilla.gnome.org/show_bug.cgi?id=340066
queue_resize basically tells the parent widget that it may need
to pick a different size/layout. However, for a hidden child widget
that should never be needed. It may be that the widget is in a
sizegroup that has ignore_hidden == FALSE though, so it may
affect the size group calculations.
However, if a widget is not visible and not in a size group then
its safe to avoid the resize, as the widget will be resized on
becoming visible anyway.
This avoids a lot of size allocation for hidden things like menus
and tooltips.
Resizes are queued via
gtk_widget_propagate_state()
=> gtk_style_context_set_state()
=> gtk_style_context_queue_invalidate()
=> gtk_style_context_validate()
=> _gtk_widget_style_context_invalidated()
so there's no need to queue an extra one.
This way we don't need a marker on GtkWidgetParivate that needs to be
unset later, so we have all our data in the same place and can avoid
problems with reentrancy and shenanigans like that.
But the main reason I wrote that is cleaner code.
With this function now available, we can do size computation in 2
ways:
(1) Compute size with size groups
(2) Compute size without size groups
And have (1) use (2) instead of setting flags on widgets. This patch
does exactly that.
It seems we missed updating this since GTK+3, widgets cannot be
allocated less than the size they requested in thier request
phase, and explicit sizes are used only to grow the size request.
Otherwise the evil widgets that don't chain up their map and unmap
vfuncs will not get updated style contexts. This is in particular true
for GtkWindow and the CSS Theming / animated backgrounds demo in
gtk-demo.
This change is necessary because the old code did not accound for corner
cases (like translucent child windows), which could stop
gtk_widget_queue_resize() to not trigger redraws.
This is a helper object to allow text widgets to implement
text selection on touch devices. It allows for both cursor
placement and text selection, displaying draggable handles
on/around the cursor and selection bound positions.
Currently, this is private to GTK+, and only available to
GtkEntry and GtkTextView.
gtk_widget_insert_action_group (widget, "foo", NULL) is valid, but
g_action_muxer_insert (muxer, "foo", NULL) is not. Use
g_action_muxer_remove() for that case.
This allows adding a GActionGroup with a given name at an arbitrary
point in the widget tree.
This patch also adds an internal _get_action_muxer() API. Calling this
will create a GActionMuxer associated with the widget. The parent of
the muxer will be the muxer of the widget's conceptual parent. For
non-menus, that is the normal parent. For menus, it is the attach
widget.
In this way, we end up with a hierarchy of GActionMuxer that largely
reflects the hierarchy of GtkWidget, but only in places that the action
context has been requested. These muxers are the ones on which the
inserted actions groups are installed.
A following patch will add a user of this API.
When a widget is app_paintable, its background should not be drawn by
the theme, thus we should not try to override its background again when
style-updated is fired.
This is a bit of a hack, but it fixes gray surfaces observed for DnD
windows with recent GTK+.
Add an internal API that allows GtkStyleContext to create a widget path
for the widget and with that bypassing gtk_widget_get_path() and that
function caching the path.
Deprecate public API where appropriate and make it no-ops.
Remove all calls to it.
Get rid of the 'transition' css property.
For now, this means spinners don't animate anymore.
... and actually set the widget on the style context. Note that this
function does not take a reference on the widget, which is a very good
reason to keep it private.
va_copy() is not universally available, and we already have a G_VA_COPY
macro that emulates the behaviour of va_copy() when it's not available, or
simply calls va_copy() if it's there
This patch adds a capture phase to GTK+'s event propagation
model. Events are first propagated from the toplevel (or the
grab widget, if a grab is in place) down to the target widget
and then back up. The second phase is using the existing
::event signal, the new capture phase is using a private
API instead of a public signal for now.
This mechanism can be used in many places where we currently
have to prevent child widgets from getting events by putting
an input-only window over them. It will also be used to implement
kinetic scrolling in subsequent patches.
http://bugzilla.gnome.org/show_bug.cgi?id=641836
We automatically request more motion events in behalf of
the original widget if it listens to motion hints. So
the capturing widget doesn't need to handle such
implementation details.
We are not making event capture part of the public API for 3.4,
which is why there is no ::captured-event signal.
We don't want to fallback for 'random' touch sequences, since
that could lead to all kinds of pairedness and other violations.
Since the X server already tells us what touch events it would
have used for emulating pointer events, we just use that information
here.
gtk_window_get/set_attached_to() is a new API that allows for windows to
be attached to a GtkWidget.
The attachment is a logical binding between the toplevel window and the
widget that generated it; this kind of information is currently used to
propagate style information from the widget to the window, but is also
useful e.g. for accessibility.
https://bugzilla.gnome.org/show_bug.cgi?id=666103
'window-unfocused' is too long and mentions "focus" which is historically
loaded with the meaning "input focus".
'backdrop' isn't generally used in GUI speak and still conveys the state the
widgets in an unfocused or background toplevel window are in.
