Maybe you should check the file FontEngine .*:

-    int calc_width(std::string text);
-    Point calc_size(std::string text_with_newlines, int width);
-    void render(std::string text, int x, int y, int justify, SDL_Surface *target, int color);
-    void render(std::string text, int x, int y, int justify, SDL_Surface *target, int width, int color);
-    void renderShadowed(std::string text, int x, int y, int justify, SDL_Surface *target, int color);
-    void renderShadowed(std::string text, int x, int y, int justify, SDL_Surface *target, int width, int color);

To const ref:

+    int calc_width(const std::string& text);
+    Point calc_size(const std::string& text_with_newlines, int width);
+    void render(const std::string& text, int x, int y, int justify, SDL_Surface *target, int color);
+    void render(const std::string& text, int x, int y, int justify, SDL_Surface *target, int width, int color);
+    void renderShadowed(const std::string& text, int x, int y, int justify, SDL_Surface *target, int color);
+    void renderShadowed(const std::string& text, int x, int y, int justify, SDL_Surface *target, int width, int color);