String + RGBA.swift

extension UIColor {
    var redValue: CGFloat{ return CIColor(color: self).red }
    var greenValue: CGFloat{ return CIColor(color: self).green }
    var blueValue: CGFloat{ return CIColor(color: self).blue }
    var alphaValue: CGFloat{ return CIColor(color: self).alpha }
    
    convenience init(r: CGFloat, g: CGFloat, b: CGFloat, a: CGFloat = 1) {
        self.init(red: r / 255, green: g / 255, blue: b / 255, alpha: a)
    }
}