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. In Swift, this behaviour can be controlled by overriding the method,

gestureRecognizer(_:shouldRecognizeSimultaneouslyWith:)^1,

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:

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
    }
}

Here's the crucial override in Objective-C^2:

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