touch-bar-simulator/Touch Bar Simulator/TouchBarView.swift

import Cocoa

final class TouchBarView: NSView {
	private var stream: CGDisplayStream?
	private let displayView = NSView()

	override init(frame: CGRect) {
		super.init(frame: .zero)
		wantsLayer = true
		start()
		setFrameSize(DFRGetScreenSize())
	}

	@available(*, unavailable)
	required init?(coder: NSCoder) {
		fatalError("init(coder:) has not been implemented")
	}

	deinit {
		stop()
	}

	override func acceptsFirstMouse(for event: NSEvent?) -> Bool {
		return true
	}

	func start() {
		stream = SLSDFRDisplayStreamCreate(0, .main) { status, _, frameSurface, _ in
			guard status == .frameComplete else {
				return
			}

			self.layer!.contents = frameSurface
		} .takeUnretainedValue()

		DFRSetStatus(2)
		stream?.start()
	}

	func stop() {
		guard let stream = stream else {
			return
		}

		DFRSetStatus(0)
		stream.stop()
		self.stream = nil
	}

	private func mouseEvent(_ event: NSEvent) {
		let location = convert(event.locationInWindow, from: nil)
		DFRFoundationPostEventWithMouseActivity(event.type, location)
	}

	override func mouseDown(with event: NSEvent) {
		mouseEvent(event)
	}

	override func mouseUp(with event: NSEvent) {
		mouseEvent(event)
	}

	override func mouseDragged(with event: NSEvent) {
		mouseEvent(event)
	}
}