如何使用非透明窗口创建内部透明的nsview

import Cocoa

class TransparentView: NSView {
    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)
        
        // 绘制自定义的透明内容
        // ...
    }
}

class ViewController: NSViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建一个无边框的窗口
        let window = NSWindow(contentRect: NSRect(x: 0, y: 0, width: 400, height: 300), styleMask: .borderless, backing: .buffered, defer: false)
        window.backgroundColor = NSColor.clear
        
        // 创建一个透明的NSView
        let transparentView = TransparentView(frame: NSRect(x: 0, y: 0, width: 400, height: 300))
        transparentView.wantsLayer = true
        transparentView.layer?.backgroundColor = NSColor.clear.cgColor
        
        // 在NSView上添加子图层或视图
        // ...
        
        // 将NSView添加到窗口的contentView中
        window.contentView?.addSubview(transparentView)
        
        // 显示窗口
        window.makeKeyAndOrderFront(nil)
    }
}