For Vega-Lite 5 params allowing signals and selections to be used in a
specification.
Simple constant parameter. Should show bars with 5px corner radius.
Parameters bound to interactive input elements.
Expression that resizes bar width by height of vis.
Interval selection with default unselected.
Paintbrush selection parameters with ctrl and shift keys both held down.
Opacity determined by slider value, and size is determined by that of
the clicked point’s Miles_per_Gallon.
Predicate expressions to use checkbox and mouseover values directly.
Predicate expressions to for cross filtering (interval selection in
left, filters in right chart).
Predicate expressions to for cross filtering (interval selection in
lower, sets extent of upper chart).
Predicate expressions to for cross filtering (interval selection in
lower, sets domain of upper chart).