def theme=(options)
reset_themes
defaults = {
:colors => %w(black white),
:additional_line_colors => [],
:marker_color => 'white',
:marker_shadow_color => nil,
:font_color => 'black',
:background_colors => nil,
:background_image => nil
}
@theme_options = defaults.merge options
@colors = @theme_options[:colors]
@marker_color = @theme_options[:marker_color]
@marker_shadow_color = @theme_options[:marker_shadow_color]
@font_color = @theme_options[:font_color] || @marker_color
@additional_line_colors = @theme_options[:additional_line_colors]
render_background
end