Create UIColor from RGB, RGBA, Hex or Hex-String ("#ffffff")

UIColor+Initializers.swift

public extension UIColor {

    /// Create color from RGB(A)
    ///
    /// Parameters:
    ///  - absoluteRed: Red value (between 0 - 255)
    ///  - green:       Green value (between 0 - 255)
    ///  - blue:        Blue value (between 0 - 255)
    ///  - alpha:       Blue value (between 0 - 255)
    ///
    /// Returns: UIColor instance.
    convenience init(absoluteRed red: Int, green: Int, blue: Int, alpha: Int = 255) {
        let normalizedRed = CGFloat(red) / 255.0
        let normalizedGreen = CGFloat(green) / 255.0
        let normalizedBlue = CGFloat(blue) / 255.0
        let normalizedAlpha = CGFloat(alpha) / 255.0

        self.init(
            red: normalizedRed,
            green: normalizedGreen,
            blue: normalizedBlue,
            alpha: normalizedAlpha
        )
    }

    /// Create color from an hexadecimal integer value (e.g. 0xFFFFFF)
    ///
    /// Note:
    ///  - Based on: http://stackoverflow.com/a/24263296
    ///
    /// Parameters:
    ///  - hex: Hexadecimal integer for color
    ///
    /// Returns: UIColor instance.
    convenience init(hex: Int) {
        self.init(
            absoluteRed: (hex >> 16) & 0xff,
            green: (hex >> 8) & 0xff,
            blue: hex & 0xff
        )
    }

    /// Create color from an hexadecimal string value (e.g. "#FFFFFF" / "FFFFFF")
    ///
    /// Note:
    ///  - Based on: http://stackoverflow.com/a/27203691
    ///
    /// Parameters:
    ///  - hex: Hexadecimal string for color
    ///
    /// Returns: UIColor instance.
    convenience init(hex: String) {
        var normalizedHexColor = hex
            .trimmingCharacters(in: .whitespacesAndNewlines)
            .uppercased()

        if normalizedHexColor.hasPrefix("#") {
            normalizedHexColor = String(normalizedHexColor.dropFirst())
        }

        // Convert to hexadecimal color (string) to integer
        var hex: UInt32 = 0
        Scanner(string: normalizedHexColor).scanHexInt32(&hex)

        self.init(
            hex: Int(hex)
        )
    }
}