# File lib/color/rgb.rb, line 249
  def mix_with(mask, opacity)
    opacity /= 100.0
    rgb = self.dup
    
    rgb.r = (@r * opacity) + (mask.r * (1 - opacity))
    rgb.g = (@g * opacity) + (mask.g * (1 - opacity))
    rgb.b = (@b * opacity) + (mask.b * (1 - opacity))

    rgb
  end