windowController.swift

import Cocoa

class WindowController: NSWindowController {

    override func windowDidLoad() {
        super.windowDidLoad()
        
        print("it works!")
        
        if let window = window, let screen = NSScreen.main {
            let screenRect = screen.visibleFrame
            
            window.setFrame(
                NSRect(x: screenRect.origin.x, y: screenRect.origin.y, width: screenRect.width / 2.0, height: screenRect.height),
                display: true
            )
            
            print(screenRect.origin.x, screenRect.origin.y, screenRect.width, screenRect.height)
        }
    }
}