HTMLColor.rb

class HTMLColor

  attr_accessor :hex, :red, :green, :blue

  Colors = %w(red green blue)
  Spectrum = %w(white black grey) + Colors

  def initialize(hex)
    @hex = hex.gsub(/#|0x/, "")
    @red = @hex[0..1].hex
    @green = @hex[2..3].hex
    @blue = @hex[4..5].hex
  end
  
  Colors.each { |color|
    define_method("#{color}!") { |val|
      instance_variable_set("@#{color}", instance_variable_get("@#{color}") + val)
    }
    define_method("#{color}?") {
      val = instance_variable_get("@#{color}")
      other_colors = Colors.select { |c| c != color }
      val > send(other_colors.first) && val > send(other_colors.last)
    }
  }
  
  def white?
    @red == 255 && @green == 255 && @blue == 255
  end
  
  def black?
    @red == 0 && @green == 0 && @blue == 0
  end
  
  def grey?
    !black? && !white? && @red == @green && @green == @blue
  end
  
  def main_color
    Spectrum.each { |color|
      return color if send("#{color}?")
    }
  end
  
  def primary_color?
    Colors.include?(main_color)
  end
  
  def lighter!(value = 10)
    @red += value
    @green += value
    @blue += value
  end
  alias :white! :lighter!
  
  def darker!(value = 10)
    @red -= value
    @green -= value
    @blue -= value
  end
  alias :black! :darker!
  
  def saturate!(value = 10)
    send("#{main_color}!", value) if main_color != 'grey'
  end

  def to_s(txt = "#")
    Colors.each { |color| txt << "%02X" % instance_variable_get("@#{color}") }
    txt
  end
  alias :hex :to_s
  
  def to_a
    [@red, @green, @blue]
  end
  
  def to_h
    { :red => @red, :green => @green, :blue => @blue }
  end
  
end