extension UIColor {
    public convenience init?(hex: String) {
        var hexColor = hex.trimmingCharacters(in: .whitespacesAndNewlines)
        hexColor = hexColor.replacingOccurrences(of: "#", with: "")

        var r: CGFloat = 0.0, g: CGFloat = 0.0, b: CGFloat = 0.0, a: CGFloat = 1.0

        let scanner = Scanner(string: hexColor)
        var hexNumber: UInt64 = 0

        guard scanner.scanHexInt64(&hexNumber) else {
            return nil
        }

        switch hexColor.count {
        case 3: // RGB (e.g., #RGB)
            r = CGFloat((hexNumber & 0xF00) >> 8) / 15.0
            g = CGFloat((hexNumber & 0x0F0) >> 4) / 15.0
            b = CGFloat(hexNumber & 0x00F) / 15.0
        case 4: // RGBA (e.g., #RGBA)
            r = CGFloat((hexNumber & 0xF000) >> 12) / 15.0
            g = CGFloat((hexNumber & 0x0F00) >> 8) / 15.0
            b = CGFloat((hexNumber & 0x00F0) >> 4) / 15.0
            a = CGFloat(hexNumber & 0x000F) / 15.0
        case 6: // RRGGBB (e.g., #RRGGBB)
            r = CGFloat((hexNumber & 0xFF0000) >> 16) / 255.0
            g = CGFloat((hexNumber & 0x00FF00) >> 8) / 255.0
            b = CGFloat(hexNumber & 0x0000FF) / 255.0
        case 8: // RRGGBBAA (e.g., #RRGGBBAA)
            r = CGFloat((hexNumber & 0xFF000000) >> 24) / 255.0
            g = CGFloat((hexNumber & 0x00FF0000) >> 16) / 255.0
            b = CGFloat((hexNumber & 0x0000FF00) >> 8) / 255.0
            a = CGFloat(hexNumber & 0x000000FF) / 255.0
        default:
            return nil
        }

        self.init(red: r, green: g, blue: b, alpha: a)
    }
}