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

UIColor+RGBA.swift

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

    /// The RGBA (red, green, blue, alpha) components of a color, in the range [0, 255].
    struct RGBA: 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 alpha component of the color, in the range [0, 255].
        var alpha: Int

    }

    /// The RGBA (red, green, blue, alpha) components of the color, in the range [0, 255].
    var rgba: RGBA {
        var (r, g, b, a) = (CGFloat(), CGFloat(), CGFloat(), CGFloat())
        getRed(&r, green: &g, blue: &b, alpha: &a)
        
        return RGBA(red: Int(round(r * 255.0)),
                    green: Int(round(g * 255.0)),
                    blue: Int(round(b * 255.0)),
                    alpha: Int(round(a * 255.0)))
    }

    /// Initializes a color from RGBA (red, green, blue, alpha) components.
    /// - parameter rgba: The components used to initialize the color.
    convenience init(_ rgba: RGBA) {
        self.init(red: CGFloat(rgba.red) / 255.0,
                  green: CGFloat(rgba.green) / 255.0,
                  blue: CGFloat(rgba.blue) / 255.0,
                  alpha: CGFloat(rgba.alpha) / 255.0)
    }

}