# File lib/captcha.rb, line 180
    def draw_key
      black = colorResolve( 0, 0, 0 )
      x = @x_spacing

      @key.each_byte do |b|
        c = b.chr
        y = rand( 3*@wiggle_y/4 ) + @char_height

        # compute the unrotated bounds, for determing how to increment
        err, bounds = GD::Image.stringFT( 0, @font, @font_size, 0, 0, 0, c )
        rect = Rectangle.from_array( bounds )

        # draw the character
        stringFT( black, @font, @font_size,
                  Math::PI*(rand(@rotation)-@rotation/2)/180.0,
                  x, y, c )

        x += rect.width + @x_spacing
      end
    end