Pinch, Pan, and Rotate Text Simultaneously like Snapchat [SWIFT 3]

Question

I'm trying to make a TextView that you can move around like snapchat does. I have made something similar to it, although when you try and scale while rotates, it tends to stretch horizontally infinitely and dragging can be a little buggy at times.

I have this:

func panGesture(pan: UIPanGestureRecognizer) {
    print("Being Dragged")
    if pan.state == .began {
        textViewOrigin = pan.location(in: textView)
    }else {
        let location = pan.location(in: view) // get pan location
        textView.frame.origin = CGPoint(x: location.x - textViewOrigin.x, y: location.y - textViewOrigin.y)
    }
}
func scaleGesture(_ gesture: UIPinchGestureRecognizer){
    print("Being Scaled")
    switch gesture.state{
    case.began:
        identity = textView.transform
    case.changed,.ended:
        textView.transform = identity.scaledBy(x: gesture.scale, y: gesture.scale)
    default:
        break
    }
}
func rotationGesture(sender: UIRotationGestureRecognizer){
    print("Being Rotated")
    textView.transform = textView.transform.rotated(by: sender.rotation)
    sender.rotation = 0
}

and I am trying to accomplish this:

If someone could help alter or re-write my code that would be great, thanks in advance!

Answer 1

By default, after one gesture recognizer on a view starts handling the gesture, other recognizers are ignored. This behaviour can be controlled by overriding the method (for Swift):

gestureRecognizer(_:shouldRecognizeSimultaneouslyWith:)

to return true. The default implementation returns false. To override the function just add your implementation, returning true, to your ViewController source code file.

Here is some sample Swift code (see https://developer.apple.com/documentation/uikit/uigesturerecognizerdelegate/1624208-gesturerecognizer?changes=_7):

class ViewController: UIViewController,UIGestureRecognizerDelegate {

    @IBOutlet var textField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        //add pan gesture
        let gestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan))
        gestureRecognizer.delegate = self
        textField.addGestureRecognizer(gestureRecognizer)

        //Enable multiple touch and user interaction for textfield
        textField.isUserInteractionEnabled = true
        textField.isMultipleTouchEnabled = true

        //add pinch gesture
        let pinchGesture = UIPinchGestureRecognizer(target: self, action:#selector(pinchRecognized(pinch:)))
        pinchGesture.delegate = self
        textField.addGestureRecognizer(pinchGesture)

        //add rotate gesture.
        let rotate = UIRotationGestureRecognizer.init(target: self, action: #selector(handleRotate(recognizer:)))
        rotate.delegate = self
        textField.addGestureRecognizer(rotate)


    }

    func handlePan(_ gestureRecognizer: UIPanGestureRecognizer) {
        if gestureRecognizer.state == .began || gestureRecognizer.state == .changed {

            let translation = gestureRecognizer.translation(in: self.view)
            // note: 'view' is optional and need to be unwrapped
            gestureRecognizer.view!.center = CGPoint(x: gestureRecognizer.view!.center.x + translation.x, y: gestureRecognizer.view!.center.y + translation.y)
            gestureRecognizer.setTranslation(CGPoint.zero, in: self.view)
        }

    }

    func pinchRecognized(pinch: UIPinchGestureRecognizer) {

        if let view = pinch.view {
            view.transform = view.transform.scaledBy(x: pinch.scale, y: pinch.scale)
            pinch.scale = 1
        }
    }

    func handleRotate(recognizer : UIRotationGestureRecognizer) {
        if let view = recognizer.view {
            view.transform = view.transform.rotated(by: recognizer.rotation)
            recognizer.rotation = 0
        }
    }

    //MARK:- UIGestureRecognizerDelegate Methods
    func gestureRecognizer(_: UIGestureRecognizer,
        shouldRecognizeSimultaneouslyWith shouldRecognizeSimultaneouslyWithGestureRecognizer:UIGestureRecognizer) -> Bool {
        return true
    }
}

In Objective C the overriding function function is this (see https://developer.apple.com/documentation/uikit/uigesturerecognizerdelegate/1624208-gesturerecognizer?language=objc):

-(BOOL)gestureRecognizer:(UIGestureRecognizer*)aR1 shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)aR2
    {
    return YES;
    }