如何在UIButton中旋转imageView,而不是缩放它

// 创建UIButton对象
let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 100))

// 创建UIImageView对象
let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
imageView.image = UIImage(named: "image.png")

// 将UIImageView添加到UIButton中
button.addSubview(imageView)

// 旋转动画
UIView.animate(withDuration: 1.0, delay: 0.0, options: .curveLinear, animations: {
    button.imageView?.transform = CGAffineTransform(rotationAngle: CGFloat.pi)
}) { (finished) in
    // 动画完成后的操作
}