UIColor extensions

UIColor+extensions.swift

public extension UIColor {
    
    public convenience init(hex: Int, alpha: CGFloat = 1.0) {
        let red = CGFloat((hex & 0xFF0000) >> 16) / 255.0
        let green = CGFloat((hex & 0xFF00) >> 8) / 255.0
        let blue = CGFloat((hex & 0xFF)) / 255.0
        
        self.init(red: red, green: green, blue: blue, alpha: alpha)
    }
    
    public convenience init(hex string: String, alpha: CGFloat = 1.0) {
        var hex = string.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
        
        if hex.hasPrefix("#") {
            let index = hex.index(hex.startIndex, offsetBy: 1)
            hex = String(hex[index...])
        }
        
        if hex.count < 3 {
            hex = "\(hex)\(hex)\(hex)"
        }
        
        if hex.range(of: "(^[0-9A-Fa-f]{6}$)|(^[0-9A-Fa-f]{3}$)", options: .regularExpression) != nil {
            if hex.count == 3 {
                
                let startIndex = hex.index(hex.startIndex, offsetBy: 1)
                let endIndex = hex.index(hex.startIndex, offsetBy: 2)
                
                let redHex = String(hex[..<startIndex])
                let greenHex = String(hex[startIndex..<endIndex])
                let blueHex = String(hex[endIndex...])
                
                hex = redHex + redHex + greenHex + greenHex + blueHex + blueHex
            }
            
            let startIndex = hex.index(hex.startIndex, offsetBy: 2)
            let endIndex = hex.index(hex.startIndex, offsetBy: 4)
            let redHex = String(hex[..<startIndex])
            let greenHex = String(hex[startIndex..<endIndex])
            let blueHex = String(hex[endIndex...])
            
            var redInt: CUnsignedInt = 0
            var greenInt: CUnsignedInt = 0
            var blueInt: CUnsignedInt = 0
            
            Scanner(string: redHex).scanHexInt32(&redInt)
            Scanner(string: greenHex).scanHexInt32(&greenInt)
            Scanner(string: blueHex).scanHexInt32(&blueInt)
            
            self.init(red: CGFloat(redInt) / 255.0,
                      green: CGFloat(greenInt) / 255.0,
                      blue: CGFloat(blueInt) / 255.0,
                      alpha: CGFloat(alpha))
        }
        else {
            self.init(red: 0.0, green: 0.0, blue: 0.0, alpha: 0.0)
        }
    }
    
    var hexValue: String {
        var color = self
        
        if color.cgColor.numberOfComponents < 4 {
            let c = color.cgColor.components!
            color = UIColor(red: c[0], green: c[0], blue: c[0], alpha: c[1])
        }
        if color.cgColor.colorSpace!.model != .rgb {
            return "#FFFFFF"
        }
        let c = color.cgColor.components!
        return String(format: "#%02X%02X%02X", Int(c[0]*255.0), Int(c[1]*255.0), Int(c[2]*255.0))
    }
    
    public var imageValue: UIImage {
        let rect = CGRect(origin: .zero, size: CGSize(width: 1, height: 1))
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()!
        context.setFillColor(self.cgColor)
        context.fill(rect)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage!
    }
    
    static func colorFromRGB(red:CGFloat , green:CGFloat , blue:CGFloat)->UIColor {
        return UIColor(red: red/255, green: green/255, blue: blue/255, alpha: 1)
    }
}