An extension of the iOS class UIColor to provide conversion to and from RGB (red, green, blue) colors.

UIColor+RGB.swift

/// An extension to provide conversion to and from RGB (red, green, blue) colors.
extension UIColor {

    /// The RGB (red, green, blue) components of a color, in the range [0, 255].
    struct RGB: Hashable {

        /// The red component of the color, in the range [0, 255].
        var red: Int
        /// The green component of the color, in the range [0, 255].
        var green: Int
        /// The blue component of the color, in the range [0, 255].
        var blue: Int

    }

    /// The RGB (red, green, blue) components of the color, in the range [0, 255].
    var rgb: RGB {
        var (r, g, b) = (CGFloat(), CGFloat(), CGFloat())
        getRed(&r, green: &g, blue: &b, alpha: nil)

        return RGB(red: Int(round(r * 255.0)),
                   green: Int(round(g * 255.0)),
                   blue: Int(round(b * 255.0)))
    }

    /// Initializes a color from RGB (red, green, blue) components.
    /// - parameter rgb: The components used to initialize the color.
    /// - parameter alpha: The alpha value of the color.
    convenience init(_ rgb: RGB, alpha: CGFloat = 1.0) {
        self.init(red: CGFloat(rgb.red) / 255.0,
                  green: CGFloat(rgb.green) / 255.0,
                  blue: CGFloat(rgb.blue) / 255.0,
                  alpha: alpha)
    }

}