Ruby color module - for blending two colors, lightening colors, and darkening colors.

color.rb

module Color
    def self.to_hex(c) # convert decimal to hex
        n = c.to_i.to_s(16)
        n = '0' + n unless n.length > 1 # 2 characters
        n
    end
    
    def self.to_dec(c) # convert hex to decimal
        c.to_i(16)
    end
    
    def self.blend(color1, color2, ratio = 0.5)
        colors = 3.times.map do |i| # R, G, B
            (to_dec(color2[i*2,2]) * ratio) + (to_dec(color1[i*2,2]) * (1-ratio))
        end
        
        colors.map { |a| to_hex(a) }.join
    end
    
    def self.lighten(color, ratio = 0.5)
        colors = 3.times.map do |i| # R, G, B
            [(to_dec(color[i*2,2]) + 255) * ratio,255].min
        end
        
        colors.map { |a| to_hex(a) }.join
    end
    
    def self.darken(color, ratio = 0.5)
        ratio = 1.0 - ratio # inverse
        
        colors = 3.times.map do |i| # R, G, B
            to_dec(color[i*2,2]) * ratio
        end
        
        colors.map { |a| to_hex(a) }.join
    end
end