Fix velocity unit names used in cargo payments graph window

src/graph_gui.cpp

@@ -1501,7 +1501,7 @@ struct PaymentRatesGraphWindow : BaseGraphWindow {
 			case WID_GRAPH_FOOTER_CUSTOM:
 				if (_cargo_payment_x_mode) {
 					SetDParam(0, STR_GRAPH_CARGO_PAYMENT_RATES_X_LABEL_SPEED);
-					SetDParam(1, STR_UNIT_NAME_VELOCITY_IMPERIAL + _settings_game.locale.units_velocity);
+					SetDParam(1, GetVelocityUnitName(VEH_TRAIN));
 				} else {
 					if (_settings_time.time_in_minutes) {
 						SetDParam(0, STR_GRAPH_CARGO_PAYMENT_RATES_X_LABEL_MINUTES);

src/strings.cpp

@@ -858,6 +858,31 @@ static const Units _units_time_years_or_minutes[] = {
 	{ { 12 }, STR_UNITS_MINUTES, 0 },
 };
 
+StringID GetVelocityUnitName(VehicleType type)
+{
+	uint8_t setting = (type == VEH_SHIP || type == VEH_AIRCRAFT) ? _settings_game.locale.units_velocity_nautical : _settings_game.locale.units_velocity;
+
+	assert(setting < lengthof(_units_velocity_calendar));
+	assert(setting < lengthof(_units_velocity_realtime));
+	static_assert(lengthof(_units_velocity_calendar) == 5 && lengthof(_units_velocity_realtime) == 5);
+
+	switch (setting) {
+		case 0:
+		case 1:
+		case 2:
+			return STR_UNIT_NAME_VELOCITY_IMPERIAL + setting;
+
+		case 3:
+			return EconTime::UsingWallclockUnits() ? STR_UNIT_NAME_VELOCITY_GAMEUNITS_WALLCLOCK : STR_UNIT_NAME_VELOCITY_GAMEUNITS;
+
+		case 4:
+			return STR_CONFIG_SETTING_LOCALISATION_UNITS_VELOCITY_KNOTS;
+
+		default:
+			NOT_REACHED();
+	}
+}
+
 /**
  * Get the correct velocity units depending on the vehicle type and whether we're using real-time units.
  * @param type VehicleType to convert velocity for.

src/strings_func.h

@@ -71,6 +71,8 @@ uint32_t GetStringGRFID(StringID string);
 uint ConvertKmhishSpeedToDisplaySpeed(uint speed, VehicleType type);
 uint ConvertDisplaySpeedToKmhishSpeed(uint speed, VehicleType type);
 
+StringID GetVelocityUnitName(VehicleType type);
+
 /**
  * Pack velocity and vehicle type for use with SCC_VELOCITY string parameter.
  * @param speed Display speed for parameter.