addBehavior method
Attaches a behavior to the chart.
Setting a behavior with the same role as a behavior already attached to the chart will replace the old behavior. The old behavior's removeFrom method will be called before we attach the behavior.
Implementation
void addBehavior(ChartBehavior<D> behavior) {
final role = behavior.role;
if (role != null && _behaviorRoleMap[role] != behavior) {
// Remove any old behavior with the same role.
removeBehavior(_behaviorRoleMap[role]);
// Add the behavior.
_behaviorRoleMap[role] = behavior;
}
// Add the behavior if it wasn't already added.
if (!_behaviorStack.contains(behavior)) {
_behaviorStack.add(behavior);
behavior.attachTo(this);
}
}