There is some open question here whether the interface
should be implemented on the outer or the inner widget
of the entry-text pairs. For now, our hand is forced,
since only GtkText provides access to the layout that
we need for implementing many of the interface methods.
This is a not-quite-complete implementation of the
Text interface for GtkLabel. The missing parts are
anything around extents and positions, as well as
the ScrollSubstring apis.
This translates relations as far as the match.
I'm not sure yet what we can do about the fact that
atspi expects relations to be bidirectional (ie have
label-for *and* labelled-by) while aria has only one
direction.
It turns out that accerciser depends on this undocumented
method that is not in the xml at all, otherwise interface
sections in the accerciser ui never get enabled.
The ARIA spec defines the mechanism for determining the name of an
accessible element—see §4.3 of the WAI-ARIA spec.
We follow the specification as much as it makes sense for GTK to do
so:
1. if the element is hidden, return an empty string
1. if the element has a labelled-by relation set, retrieve the
label of the related element
2. if the element has a label property set, use the value of
the property
3. if neither labelled-by nor label attributes are set, we use
the role to compute the name:
- for a `range` role, we return the contents of the value of
the `value-text` or `value-now` properties
- for any other role, we return a textual representation of
the GtkAccessibleRole enumeration value
When we create the first AT-SPI context we also need to register the
accessible root on the accessibility bus. The accessible root object is
the main entry point of an accessible application, and it holds the
global state to present to the ATs that connect to the bus.
Since we need to check at run time what kind of AT context to use, we
need a hook into the whole GDK backend machinery. The display connection
seems to be the best choice, in this case, as it allows us to determine
whether we're running on an X11 or Wayland system, and thus whether we
should create a GtkAtSpiContext.
This requires some surgery to fix the GtkATContext creation function, in
order to include a GdkDisplay instance.
Does not do anything, at the moment, but it's going to get filled out
soon.
The backend is selected depending on the platform being compiled in;
since we're using AT-SPI on X11 and Wayland, and we don't have other
accessibility implementations, we currently don't care about run time
selection, but we're going to have to deal with that.
And generate the code for the DBus interfaces.
We don't want the full object manager experience, here, because we're
going to have a single object responding to various interfaces and
remote method calls. For this reason, we're not using the gnome module
in Meson to call gdbus-codegen for us: we need to use the interface info
command line arguments, and those are not available from Meson.
Like we do for GdkX11. We can't use all of the public C API, but we can
expose enough type information to allow non-C developers to actually
check if they are running the Wayland GDK backend or not—plus some
additional Wayland-specific API.
The GdkWayland API takes generic GDK types and performs a run time
check, which means we need to properly annotate the actual expected
type in order to have methods recognised as such.
