Since we mention abstract roles in the documentation
for GtkAccessibleRole, we should say what roles are
abstract. Doing this shows that we actually use two
abstract roles heavily, ourselves: WIDGET and WINDOW.
Use the TREE_GRID, ROW, COLUMN_HEADER and GRID_CELL roles
for the various widgets involved in a GtkColumnView. To
enable this, we subclass GtkListView for the internal
list in the column view.
Use the label accessible role for GtkLabel. ARIA has some
ominous wording about it going way, but while we have it,
GtkLabel is the obvious candidate for carrying it.
Update the documentation and add a test.
Reduce the amount of subclassing, by handling collection of fundamental
types directly from the generic code paths. We now handle boolean,
tristate, integer, number, string, and relation values in the generic
code path; if an attribute supports the "undefined" value, we return the
undefined value singleton.
Drop roles and properties that were deprecated in WAI-ARIA 1.1, and add
new roles and properties defined in WAI-ARIA 1.2 and later.
We also split the relationship properties into their own enumeration, so
we can keep the GtkAccessibleProperty type more compact.
It's pointless, we can use an explicit value of `-1` everywhere.
Additionally, it complicates all code that uses the state enumeration as
an array index, since now we need to guard against a negative offset.
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.
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.
This is an enum that we're gonna use soon and it's worth introducing as a
separate commit.
The intention is to have meaningful names for return values in
comparison functions.
This gives us a hook to walk the widget tree whenever a global
setting changes and do per-widget invalidations. This will
replace gtk_style_context_reset_widgets().
This is used for widgets that contain the focus widget,
reserving the focused state for the focus location itself.
This aligns our focus state handling with
https://www.w3.org/TR/selectors-4/
Allow setting the scope for a controller. The scope determines at what
point in event propagation the shortcuts will be activated.
Local scope is the usual activation, global scope means that the root
widget activates the shortcuts - ie they are activated at the very
start of event propagation (for global capture events) or the very end
(for global bubble events).
Managed scope so far is unimplemented.
This is supposed to be used to replace accelerators and mnemonics.
Allow setting the scope for a controller. The scope determines at what
point in event propagation the shortcuts will be activated.
Local scope is the usual activation, global scope means that the root
widget activates the shortcuts - ie they are activated at the very
start of event propagation (for global capture events) or the very end
(for global bubble events).
Managed scope so far is unimplemented.
This is supposed to be used to replace accelerators and mnemonics.
Instead of playing games with mapping negative symbolic values to
positive ones, let's use the appropriate constants everywhere. This
allows us to use:
GTK_CONSTRAINT_STRENGTH_WEAK * 2
Or
GTK_CONSTRAINT_STRENGTH_STRONG + 1
In code using the public API.
We also store the strength values as integers, so we can compare them
properly, and only turn them into doubles when they are inserted into
the solver, just like every other variable.
GtkConstraintSolver is an implementation of the Cassowary constraint
solving algorithm:
http://constraints.cs.washington.edu/cassowary/
The Cassowary method allows to incrementally solve a tableau of linear
equations, in the form of:
x = y × coefficient + constant
with different weights, or strengths, applied to each one.
These equations can be used to describe constraints applied to a layout
of UI elements, which allows layout managers using the Cassowary method
to quickly, and efficiently, lay out widgets in complex relations
between themselves and their parent container.
