Add: Function to get largest cargo icon size.

src/cargotype.cpp

@@ -9,6 +9,7 @@
 
 #include "stdafx.h"
 #include "cargotype.h"
+#include "core/geometry_func.hpp"
 #include "newgrf_cargo.h"
 #include "string_func.h"
 #include "strings_func.h"
@@ -70,6 +71,19 @@ void SetupCargoForClimate(LandscapeID l)
 	std::fill(insert, std::end(CargoSpec::array), CargoSpec{});
 }
 
+/**
+ * Get dimensions of largest cargo icon.
+ * @return Dimensions of largest cargo icon.
+ */
+Dimension GetLargestCargoIconSize()
+{
+	Dimension size = {0, 0};
+	for (const CargoSpec *cs : _sorted_cargo_specs) {
+		size = maxdim(size, GetSpriteSize(cs->GetCargoIcon()));
+	}
+	return size;
+}
+
 /**
  * Get the cargo ID of a default cargo, if present.
  * @param l Landscape
@@ -179,7 +193,7 @@ static bool CargoSpecClassSorter(const CargoSpec * const &a, const CargoSpec * c
 void InitializeSortedCargoSpecs()
 {
 	_sorted_cargo_specs.clear();
-	/* Add each cargo spec to the list. */
+	/* Add each cargo spec to the list, and determine the largest cargo icon size. */
 	for (const CargoSpec *cargo : CargoSpec::Iterate()) {
 		_sorted_cargo_specs.push_back(cargo);
 	}

src/cargotype.h

@@ -185,6 +185,7 @@ void SetupCargoForClimate(LandscapeID l);
 CargoID GetCargoIDByLabel(CargoLabel cl);
 CargoID GetCargoIDByBitnum(uint8_t bitnum);
 CargoID GetDefaultCargoID(LandscapeID l, CargoType ct);
+Dimension GetLargestCargoIconSize();
 
 void InitializeSortedCargoSpecs();
 extern std::array<uint8_t, NUM_CARGO> _sorted_cargo_types;