How can I capture which direction is being panned using UIPanGestureRecognizer?

Question

Ok so I have been looking around at just about every option under the sun for capturing multi-touch gestures, and I have finally come full circle and am back at the UIPanGesture

Answer 1

Here's an easy to detect before the gesture recognizer begins:

public override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
    guard let panRecognizer = gestureRecognizer as? UIPanGestureRecognizer else {
        return super.gestureRecognizerShouldBegin(gestureRecognizer)
    }

    // Ensure it's a horizontal drag
    let velocity = panRecognizer.velocity(in: self)
    if abs(velocity.y) > abs(velocity.x) {
        return false
    }
    return true
}

If you want a vertical only drag, you can switch the x and y.