We cannot use the given "for size" when querying our children, because
the constraint layout has no idea about the opposite size of its
children until the layout is complete.
Additionally, we should only suggest an opposite size for the layout if
we have one, instead of suggesting a weak zero size.
The size constraints are transient to measurement and allocation, so
they don't really need to be stored inside the GtkLayoutChild subclass
created by a GtkConstraintLayout.
The relations between left, right, width
and top, bottom, height are required for
internal consistency. It doesn't make sense
to ever drop these.
Changing the strength of these relations makes
my systems behave much more stable.
When the solver is finalized with existing
constraints, we end up with criticals when
the constraints ref finalize code calls
back into the hash table. Avoid that by
emptying the hash table beforehand.
We don't expect out of tree implementations of GtkRoot, and having the
interface structure private to the GTK code allows us to add virtual
functions involving private types.
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.
I recently turned gtk_widget_activate_action()
into a varargs function. That is more convenient
from C, but we need a non-varargs variant for
bindings. So add the old API back, under the
name gtk_widget_activate_action_variant(),
with a rename-to annotation.
The xdg_output v2 interface has a `name` property that reflects the
output name coming from the compositor.
This is the closest thing we can get to a connector name.
The migration from GdkScreen's monitor API to GdkMonitor left out a way
to get the connector's name of a monitor.
While there's no real guarantee coming from the underlying graphics
system that the connector's name is stable, some system components may
use it to uniquely identify a monitor until the next plug in/out event.
We need to create a muxer eagerly for every
widget that has class actions, since those
are otherwise missed in the action lookup
on the muxer side. But otherwise, there is
no reason to create parent muxers aggressively,
as long as we update the parent muxers on
root/unroot.
This reduces the number of muxers we create
in widget-factory from 210 to around 50.
