UIColor+Extensions.swift

import UIKit

extension UIColor 
{
    convenience init(hex: String, alpha: CGFloat = 1) 
    {
        assert(hex[hex.startIndex] == "#", "Expected hex string of format #RRGGBB")
        
        let scanner = Scanner(string: hex)
        scanner.scanLocation = 1 // skip #
        
        var rgb: UInt32 = 0
        scanner.scanHexInt32(&rgb)
        
        self.init(
            red: CGFloat((rgb & 0xFF0000) >> 16) / 255.0,
            green: CGFloat((rgb & 0xFF00) >> 8) / 255.0,
            blue: CGFloat((rgb & 0xFF)) / 255.0,
            alpha: alpha)
    }
}