String+UIImage.swift

extension String {
    
    func draw(fontSize: CGFloat) -> UIImage? {
        draw(font: .systemFont(ofSize: fontSize))
    }
    
    func draw(font: UIFont) -> UIImage? {
        draw(attributes: [.font: font], backgroundColor: .clear)
    }
    
    func draw(attributes: [NSAttributedString.Key : Any], backgroundColor: UIColor) -> UIImage? {
        let size = NSString(string: self).size(withAttributes: attributes)
        UIGraphicsBeginImageContextWithOptions(size, false, 0)
        backgroundColor.set()
        let rect = CGRect(origin: .zero, size: size)
        UIRectFill(CGRect(origin: .zero, size: size))
        (self as AnyObject).draw(in: rect, withAttributes: attributes)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}