+bool NavDisplay::isPositionedShown(FGPositioned* pos)
+{
+ SymbolRuleVector rules;
+ isPositionedShownInner(pos, rules);
+ return !rules.empty();
+}
+
+void NavDisplay::isPositionedShownInner(FGPositioned* pos, SymbolRuleVector& rules)
+{
+ string type = FGPositioned::nameForType(pos->type());
+ boost::to_lower(type);
+ if (!anyRuleForType(type)) {
+ return; // not diplayed at all, we're done
+ }
+
+ string_set states;
+ computePositionedState(pos, states);
+
+ findRules(type, states, rules);
+}
+