如何保持放置在顶部的UIImage与视图的纵横比？

// 假设imageView是要放置UIImage的视图
let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height))

// 假设image是要显示的UIImage
let image = UIImage(named: "exampleImage")

// 获取UIImage的宽度和高度
let imageWidth = image?.size.width ?? 0
let imageHeight = image?.size.height ?? 0

// 获取视图的宽度和高度
let viewWidth = imageView.frame.width
let viewHeight = imageView.frame.height

// 计算UIImage的纵横比
let aspectRatio = imageWidth / imageHeight

// 根据视图的宽度和UIImage的纵横比，计算UIImage在视图中应该显示的高度
let scaledHeight = viewWidth / aspectRatio

// 设置UIImage的frame属性，将其放置在视图的顶部，并保持纵横比
imageView.frame = CGRect(x: 0, y: 0, width: viewWidth, height: scaledHeight)

// 将UIImage添加到视图中
view.addSubview(imageView)