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.
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.
