Some widgets have different accessible roles depending on some
parameter, so we cannot set the role at class init time. For those
widgets, we add an "accessible-role" property to GtkAccessible, and we
allow setting it (only) at construction time.
Each widget type has an accessible role associated to its class, as
roles cannot change during the life time of a widget instance.
Each widget is also responsible for creating an ATContext, to proxy
state changes to the underlying accessibility infrastructure.
An Accessible implementation must create an ATContext object. UI
elements are supposed to interact with the GtkAccessible API, but we
expose GtkATContext to allow patterns like delegation.
The ATContext type is meant to be used as the base class for
implementations of the assistive technology API—the actual mechanism
needed to communicate to components like the screen reader, or any other
AT.
Every time the widget state changes, the ATContext is meant to broadcast
the state change; and every time the AT queries the state of a UI
element, the ATContext is meant to provide that information.
We also have a "test" ATContext implementation, which is meant to be
used to write tests to verify that changes are propagated without
requiring a whole desktop session.
All accessible properties and states may have one of the following
types:
- true/false
- true/false/undefined
- true/false/mixed/undefined
- reference (to another UI element)
- reference list
- integer
- number (real numerical value)
- string
- token (one of a limited set of allowed values)
- token list
See: https://www.w3.org/WAI/PF/aria/states_and_properties#propcharacteristic_value
The GtkAccessibleValue is a simple reference counted type that can be
"subclassed" to implement each value type.
This initial commit adds GtkAccessibleValue and the basic subclasses for
plain boolean, tristate (true/false/undefined), and token types,
including statically allocated values that can be shared instead of
allocated.
GtkAccessible is an interface for accessible UI elements.
Currently, it doesn't do much except exist as a type; in the future, it
will be the entry point for all accessible state in GTK.
The list of roles is taken from the WAI-ARIA 1.2 specification:
https://w3c.github.io/aria/
Some of these roles do not make entirely sense from a GTK application
perspective, but we can remove them before finalizing the API.
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
We are using floats for rgb, and we don't need more precision
for hsl colors either. We use hsl for computing color expressions
like shade(), lighter() and darker(), which are not precisely
specified anyway.
This commit updates the one test where the output changes a
tiny bit due to this.
Setting a width request is not quite enough, since
gtk_widget_set_size_request() only queues a resize
when the widget is visible. Explicitly force one
here. Without this, the popup sometimes shows up
too small.
This is truly a russian doll of documentation formats:
a string containing <> inside an xml fragment in an |[ ]|
gtk-doc example in markdown in a doc comment.
Sadly, something gets escaping wrong, so the <> end up
literally in the docbook and mess up the last step of
our document formatting, even after turning them into
entities.
Work around this with an extra level of entities that
really shouldn't be necessary.
Commit 0145809a94 replace the response-requested
signal with an action, but didn't actually remove the emission
of that no-longer-existing signal.
Fixes: #2942
SSave the missing keys as a bitset and iterate over that bitset in the
step function.
Solves the problem with a large UI block at the beginning of a sort
operation when all the keys were generated, in particular when key
generation was slow.
Benchmarks for maximum time taken by a single main loop callback:
initial sort with complex GFileInfo keys
old new
32,000 items 137ms 3ms
128,000 items 520ms 31ms
initial sort with string keys
old new
32,000 items 187ms 1ms
128,000 items 804ms 3ms
When updating a (partially) sorted model, take the known runs for the
existing sort and apply them to the new sort. That way, we don't have to
check the whole model again.
Benchmarks:
appending half the items to a model of strings
old new
512,000 items 437ms 389ms
1,024,000 items 1006ms 914ms
appending 10% of the items to a model of strings
old new
512,000 items 206ms 132ms
1,024,000 items 438ms 301ms
appending 1 item to a model of strings
old new
64,000 items 1.8ms 0.00ms
512,000 items --- 0.01ms
Previously, the sort was not stable when items were added/removed while
sorting or the sort algorithm was changed.
Now the sort looks at the item position (via the key's location in the
keys array) to make sure each comparison stays stable with respect to
this position.
