To build a better world sometimes means having to tear the old one down.
-- Alexander Pierce, "Captain America: The Winter Soldier"
ATK served us well for nearly 20 years, but the world has changed, and
GTK has changed with it. Now ATK is mostly a hindrance towards improving
the accessibility stack:
- it maps to a very specific implementation, AT-SPI, which is Linux and
Unix specific
- it requires implementing the same functionality in three different
layers of the stack: AT-SPI, ATK, and GTK
- only GTK uses it; every other Linux and Unix toolkit and application
talks to AT-SPI directly, including assistive technologies
Sadly, we cannot incrementally port GTK to a new accessibility stack;
since ATK insulates us entirely from the underlying implementation, we
cannot replace it piecemeal. Instead, we're going to remove everything
and then incrementally build on a clean slate:
- add an "accessible" interface, implemented by GTK objects directly,
which describe the accessible role and state changes for every UI
element
- add an "assistive technology context" to proxy a native accessibility
API, and assign it to every widget
- implement the AT context depending on the platform
For more information, see: https://gitlab.gnome.org/GNOME/gtk/-/issues/2833
Changing the selection in the object tree is
not a useful action if we are already in the
object details. Most likely, a user who picks
an object wants to inspect its details, so
just always show them.
Fixes: #1876
Bring back the actions tab; we don't receive
changes anymore, since GtkActionMuxer lost
the GActionGroup signals for this, and the
action observer machinery has no way to listen
for all changes.
We were hiding the inspector when the window
is closed, but that has the side-effect of
keeping references to application windows,
so we would keep them artificially alive,
which can have side-effects.
So, make the inspector go away when closed.
Simplify all view model APIs and always return G_TYPE_OBJECT as the
item-type for every model.
It turns out nobody uses item-type anyway.
So instead of adding lots of APIs, forcing people to think about it and
trying to figure out how to handle filter or map models that modify item
types, just having an easy life is a better approach.
All the models need to be able to deal with any type of object going
through anyway.
Rename the DataList object to TreeData, in preparation
for adding a ListData object for list models. While
we are touching it, modernize it a bit (drop the Private
struct, use a layout manager, etc).
This makes the inspector lock up when used with any production
size list model, and blocks access to properties of the model
itself. Instead, we'll make the model available as an object
and add a data tab for list model contents, like we already
do for tree models.
