如何在Cocoa中实现渐变按钮栏

import Cocoa

class GradientButton: NSButton {
    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)
        
        let gradient = NSGradient(starting: NSColor.red, ending: NSColor.blue)
        let path = NSBezierPath(rect: dirtyRect)
        gradient?.draw(in: path, angle: 90)
    }
}