Bring Touch to your Mac app

2:08 - Custom button that overrides mouseDown

// Custom button to detect start and end of tracking
class IgnitionButton: NSButton {
    var delegate: IgnitionButtonDelegate?

    override func mouseDown(with event: NSEvent) {
        delegate?.buttonDidStartTracking()
        super.mouseDown(with: event)
        delegate?.buttonDidEndTracking()
    }
}

2:24 - Use NSControl events to detect tracking

// Use NSControl events to detect start and end of tracking
ignitionButton.addTarget(
    self,
    action: #selector(buttonDidStartTracking),
    for: [.trackingBegan, .trackingEntered]
)

ignitionButton.addTarget(
    self,
    action: #selector(buttonDidEndTracking),
    for: [.trackingExited, .trackingEndedInside]
)

ignitionButton.addTarget(
    self,
    action: #selector(buttonCancelledTracking),
    for: .trackingCancelled
)

3:13 - Mouse tracking loop

let eventMask: NSEvent.EventTypeMask = [.leftMouseDragged, .leftMouseUp]
while true {
    let nextEvent = NSApp.nextEvent(
        matching: eventMask,
        until: .distantFuture,
        inMode: .eventTracking,
        dequeue: true)
    if let nextEvent, nextEvent.type == .leftMouseUp {
        break
    }
}

4:11 - Refactored tracking functions

// Refactored tracking functions
func startTracking(at viewLocation: NSPoint) { /* ... */ }

func continueTracking(at viewLocation: NSPoint) { /* ... */ }

func endTracking(at viewLocation: NSPoint) { /* ... */ }

func cancelTracking() { /* ... */ }

4:24 - Add a touch-only pan gesture recognizer

// Add touch-only pan gesture recognizer
let touchRecognizer = NSPanGestureRecognizer(
    target: self,
    action: #selector(touchPan)
)

touchRecognizer.buttonMask = 0x0
touchRecognizer.allowedTouchTypes = .direct

wiringPanelView.addGestureRecognizer(touchRecognizer)

4:52 - Pan gesture recognizer action

// Pan gesture recognizer action function
@objc func touchPan(_ recognizer: NSPanGestureRecognizer) {
    switch recognizer.state {
    case .began:
        startTracking(at: recognizer.location(in: wiringPanelView))
    case .changed:
        continueTracking(at: recognizer.location(in: wiringPanelView))
    case .ended:
        endTracking(at: recognizer.location(in: wiringPanelView))
    case .cancelled:
        cancelTracking()
    default:
        break
    }
}

5:37 - Expand hit targets for touch

// Refactored tracking functions with expanded hit targets
func startTracking(at viewLocation: NSPoint, expandHitRect: Bool = false) {
    for node in nodes {
        if point(viewLocation, in: node.frame, expandForTouch: expandHitRect) {
            trackingNode = node
            trackingLocation = viewLocation
            return
        }
    }
}

func point(_ point: NSPoint, in rect: NSRect, expandForTouch: Bool = false) -> Bool {
    if expandForTouch {
        // Expand to minimum size of 36 points on each axis
    } else {
        // Nothing to do for mouse
    }
    return NSPointInRect(point, rect)
}

@objc func touchPan(_ recognizer: NSPanGestureRecognizer) {
    switch recognizer.state {
    case .began:
        startTracking(at: recognizer.location(in: wiringPanelView), expandHitRect: true)
    // ...
    default:
        break
    }
}

6:40 - Require two touches for scrolling

// Modify touch scrolling properties
decoratingView.enclosingScrollView?.minimumNumberOfTouchesForScrolling = 2

7:48 - Allow simultaneous slider interaction

// Simultaneous sliders
stoveControlsView.exclusiveGestureBehavior = .notExclusive

8:25 - Disable system gestures

// Disabling system gestures
stoveControlsView.window?.disablesDirectTouchSystemGestures = true

// Mac Catalyst API
extension UIViewController {
    var prefersDirectTouchSystemGesturesDisabled: Bool { get }
}

// SwiftUI API
View.directTouchSystemGesturesDisabled()

11:47 - Declare touch-native support in Info.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <!-- ... -->
    <key>NSIsTouchNative</key>
    <true/>
    <!-- ... -->
</dict>
</plist>