Zoning: Ensure that screen is refreshed when necessary in authority overlay

src/station_cmd.cpp

@@ -694,6 +694,9 @@ static CommandCost BuildStationPart(Station **st, DoCommandFlag flags, bool reus
 			(*st)->string_id = GenerateStationName(*st, area.tile, name_class);
 
 			if (Company::IsValidID(_current_company)) {
+				if (_local_company == _current_company && !HasBit((*st)->town->have_ratings, _current_company)) {
+					ZoningTownAuthorityRatingChange();
+				}
 				SetBit((*st)->town->have_ratings, _current_company);
 			}
 		}

src/town_cmd.cpp

@@ -46,6 +46,7 @@
 #include "ai/ai.hpp"
 #include "game/game.hpp"
 #include "zoom_func.h"
+#include "zoning.h"
 
 #include "table/strings.h"
 #include "table/town_land.h"
@@ -3622,7 +3623,8 @@ void ChangeTownRating(Town *t, int add, int max, DoCommandFlag flags)
 		return;
 	}
 
-	int rating = GetRating(t);
+	const int prev_rating = GetRating(t);
+	int rating = prev_rating;
 	if (add < 0) {
 		if (rating > max) {
 			rating += add;
@@ -3637,6 +3639,9 @@ void ChangeTownRating(Town *t, int add, int max, DoCommandFlag flags)
 	if (_town_rating_test) {
 		_town_test_ratings[t] = rating;
 	} else {
+		if (_local_company == _current_company && (!HasBit(t->have_ratings, _current_company) || ((prev_rating > 0) != (rating > 0)))) {
+			ZoningTownAuthorityRatingChange();
+		}
 		SetBit(t->have_ratings, _current_company);
 		t->ratings[_current_company] = rating;
 		t->UpdateVirtCoord();

src/zoning.h

@@ -62,6 +62,7 @@ void ZoningMarkDirtyStationCoverageArea(const Station *st, ZoningModeMask mask =
 inline void ZoningMarkDirtyStationCoverageArea(const Waypoint *st) { } // no-op
 
 void ZoningStationWindowOpenClose(const Station *st);
+void ZoningTownAuthorityRatingChange();
 
 void SetZoningMode(bool inner, ZoningEvaluationMode mode);
 

src/zoning_cmd.cpp

@@ -477,6 +477,16 @@ void ZoningStationWindowOpenClose(const Station *st)
 	if (mask != ZMM_NOTHING) ZoningMarkDirtyStationCoverageArea(st, mask);
 }
 
+void ZoningTownAuthorityRatingChange()
+{
+	ZoningModeMask mask = ZMM_NOTHING;
+	if (_zoning.inner == ZEM_AUTHORITY) mask |= ZMM_INNER;
+	if (_zoning.outer == ZEM_AUTHORITY) mask |= ZMM_OUTER;
+	if (mask != ZMM_NOTHING) {
+		MarkWholeScreenDirty();
+	}
+}
+
 void ClearZoningCaches()
 {
 	_zoning_cache_inner.clear();