MacOS does not display NSBezierPath line

Question

I'm trying to draw a line in my MacOS app but I do not see the line. What can be a problem?

My code looks like:

func addLine() {
    let path = NSBezierPath()
    path.move(to: NSPoint(x: 100.0, y: 100))
    path.line(to: NSPoint(x: 200.0, y: 200.0))
    NSColor.green.setFill()
    NSColor.green.setStroke()
    path.close()
    path.stroke()
}

And I call it in:

override func viewDidLoad() {
    super.viewDidLoad()

    addLine()
}

Am I doing something wrong? I just do not see anything in my window.

Answer 1

Have you created your own subclass of a NSView?

If I create a new view and add your code like so:

import Cocoa

class MyView: NSView {

    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)
        addLine()
    }

    func addLine() {
        let path = NSBezierPath()
        path.move(to: NSPoint(x: 100.0, y: 100))
        path.line(to: NSPoint(x: 200.0, y: 200.0))
        NSColor.green.setFill()
        NSColor.green.setStroke()
        path.close()
        path.stroke()
    }
}

And I then - in a storyboard - drag a "Custom View" to the canvas, change the type of the view to be MyView like so

Then I see this when running the app:

If you prefer to add the view in code, you can do something like this:

class ViewController: NSViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let myView = MyView()
        myView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(myView)
        myView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        myView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
        myView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        myView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
    }
}

So, your code seems to work, I'm just not sure how you are trying to use it.

Hope that gives you something to continue with.