如何制作带有渐变的UIButton背景图像(Swift)

import UIKit

func createGradientButton() -> UIButton {
    let button = UIButton(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
    button.setTitle("Gradient Button", for: .normal)
    button.titleLabel?.font = UIFont.systemFont(ofSize: 18)
    button.setTitleColor(.white, for: .normal)
    
    let gradientLayer = CAGradientLayer()
    gradientLayer.frame = button.bounds
    gradientLayer.colors = [UIColor.red.cgColor, UIColor.blue.cgColor]
    gradientLayer.startPoint = CGPoint(x: 0, y: 0)
    gradientLayer.endPoint = CGPoint(x: 1, y: 1)
    
    button.layer.addSublayer(gradientLayer)
    
    // 渲染渐变图层为背景图像
    UIGraphicsBeginImageContextWithOptions(button.bounds.size, false, 0)
    button.layer.render(in: UIGraphicsGetCurrentContext()!)
    let backgroundImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    button.setBackgroundImage(backgroundImage, for: .normal)
    
    return button
}

// 使用示例
let gradientButton = createGradientButton()