Extension for UIColor: - init from String hex, - get hex String from Color, - init from Int values, - create image from UIColor

UIColor+Extension.swift

import UIKit

extension UIColor {

    /// Creates image from color
    /// - Parameter size: size of returned image
    /// - Returns: UIImage
    func image(_ size: CGSize = CGSize(width: 1, height: 1)) -> UIImage {
        return UIGraphicsImageRenderer(size: size).image { rendererContext in
            self.setFill()
            rendererContext.fill(CGRect(x: 0, y: 0, width: size.width, height: size.height))
        }
    }

    func hexStringFromColor() -> String {
        let components = self.cgColor.components
        let r: CGFloat = components?[0] ?? 0.0
        let g: CGFloat = components?[1] ?? 0.0
        let b: CGFloat = components?[2] ?? 0.0
        let hexString = String.init(format: "#%02lX%02lX%02lX", lroundf(Float(r * 255)), lroundf(Float(g * 255)), lroundf(Float(b * 255)))
        return hexString
    }
    
    // MARK: - init
    public convenience init(rgbColorCodeRed red: Int, green: Int, blue: Int, alpha: CGFloat) {
        let redPart: CGFloat = CGFloat(red) / 255
        let greenPart: CGFloat = CGFloat(green) / 255
        let bluePart: CGFloat = CGFloat(blue) / 255
        self.init(red: redPart, green: greenPart, blue: bluePart, alpha: alpha)
    }

    public convenience init?(hex: String) {
        let r, g, b, a: CGFloat

        if hex.hasPrefix("#") {
            let start = hex.index(hex.startIndex, offsetBy: 1)
            let hexColor = String(hex[start...])

            if hexColor.count == 8 {
                let scanner = Scanner(string: hexColor)
                var hexNumber: UInt64 = 0

                if scanner.scanHexInt64(&hexNumber) {
                    r = CGFloat((hexNumber & 0xff000000) >> 24) / 255
                    g = CGFloat((hexNumber & 0x00ff0000) >> 16) / 255
                    b = CGFloat((hexNumber & 0x0000ff00) >> 8) / 255
                    a = CGFloat(hexNumber & 0x000000ff) / 255

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

        return nil
    }
}