diff --git a/src/color.hpp b/src/color.hpp
index c602b58c6c0b..63ed890c5e43 100644
--- a/src/color.hpp
+++ b/src/color.hpp
@@ -19,6 +19,7 @@
 #include <ostream>
 #include <string>
 #include <utility>
+#include "global.hpp"
 
 struct SDL_Color;
 
@@ -223,6 +224,15 @@ struct color_t
 			std::max<uint8_t>(a, c.a),
 		};
 	}
+
+	CONSTEXPR color_t inverse() const {
+		return {
+			static_cast<uint8_t>(255 - r),
+			static_cast<uint8_t>(255 - g),
+			static_cast<uint8_t>(255 - b),
+			a
+		};
+	}
 };
 
 inline std::ostream& operator<<(std::ostream& s, const color_t& c)
diff --git a/src/font/standard_colors.cpp b/src/font/standard_colors.cpp
index 19624ab47708..c93a0c867b88 100644
--- a/src/font/standard_colors.cpp
+++ b/src/font/standard_colors.cpp
@@ -16,17 +16,6 @@
 
 namespace font {
 
-// TODO: evalulate whether this should become a color_t member
-static color_t inverse(const color_t& color)
-{
-	return {
-		static_cast<uint8_t>(255 - color.r),
-		static_cast<uint8_t>(255 - color.g),
-		static_cast<uint8_t>(255 - color.b),
-		255 // TODO: should we respect alpha?
-	};
-}
-
 const color_t
 	NORMAL_COLOR    {0xDD, 0xDD, 0xDD},
 	GRAY_COLOR      {0x77, 0x77, 0x77},
@@ -41,7 +30,7 @@ const color_t
 	LABEL_COLOR     {0x6B, 0x8C, 0xFF},
 	BIGMAP_COLOR    {0xFF, 0xFF, 0xFF};
 
-const color_t DISABLED_COLOR = inverse(PETRIFIED_COLOR);
+const color_t DISABLED_COLOR = PETRIFIED_COLOR.inverse();
 
 const color_t
 	weapon_color           {245, 230, 193},