    # File lib/rubygame/surface.rb, line 581
      def to_display_alpha
        newsurf =
          if( Rubygame.init_video_system() == 0 )
            SDL.DisplayFormatAlpha( @struct )
          else
            nil
          end

        if( newsurf.nil? or newsurf.pointer.null?)
          raise( Rubygame::SDLError,
                 "Could not convert the Surface to display format "+
                 "with alpha channel: #{SDL.GetError()}" )
        end

        # Wrap it
        return self.class.new( newsurf )
      end