text: #include <SDL.h>
  
  class ExtractSurface {
  public:
    static ExtractSurface& getInstance();
    SDL_Surface* get(SDL_Surface*, int, int, int, int) const;
  private:
    Uint32 getpixel(SDL_Surface*, int, int) const;
    void putpixel(SDL_Surface *, int, int, Uint32) const;
  };
  