# File lib/gruff/base.rb, line 300
    def theme=(options)
      reset_themes()

      defaults = {
        :colors => ['black', 'white'],
        :additional_line_colors => [],
        :marker_color => 'white',
        :font_color => 'black',
        :background_colors => nil,
        :background_image => nil
      }
      @theme_options = defaults.merge options

      @colors = @theme_options[:colors]
      @marker_color = @theme_options[:marker_color]
      @font_color = @theme_options[:font_color] || @marker_color
      @additional_line_colors = @theme_options[:additional_line_colors]

      render_background
    end