def update_screen(image)
      if @show_prompt
        MiniTerm.print("\r#{prompt.text}\r")
        @show_prompt = false
      end

      (0...active_width).each do |index|
        if (image_char = image[index]) != window_buffer[index]
          MiniTerm.set_posn(column: prompt.length + index)
          MiniTerm.print(image_char)
        end
      end
    end
def update_screen(image)
      if @show_prompt
        MiniTerm.print("\r#{prompt.text}\r")
        @show_prompt = false
      end

      (0...active_width).each do |index|
        if (image_char = image[index]) != window_buffer[index]
          MiniTerm.set_posn(column: prompt.length + index)
          MiniTerm.print(image_char)
        end
      end
    end
Bring the screen into agreement with the image.