Get a UIImage with solid color

UIImage+SolidColor.swift

extension UIImage {
    public convenience init?(color: UIColor, size: CGSize = CGSize(width: 1, height:1)) {
        let rect = CGRect(origin: .zero, size: size)
        UIGraphicsBeginImageContextWithOptions(rect.size, false, 1.0)
        color.setFill()
        UIRectFill(rect)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        guard let cgImage = image?.cgImage else {
            return nil
        }
        self.init(cgImage: cgImage)
    }
}