UIPanGestureRecognizer to rotate mapView - ios

Question

I have a method for panning the map using a UIPanGestureRecognizer however it doesn't rotate correctly (I want to be able to make circle motions that cause the camera to move in a circle), is there a better approach here?
#objc func panMap (sender: UIPanGestureRecognizer) {
if sender.state == .began {
print("began")
} else if sender.state == .changed {
// rotating map camera
let position = sender.translation(in: mapView)
let newDirection = mapView.camera.heading.advanced(by: (Double(position.x) + Double(position.y)))
let newCamera: MKMapCamera = MKMapCamera(lookingAtCenter: mapView.camera.centerCoordinate, fromDistance: mapView.camera.altitude, pitch: mapView.camera.pitch, heading: newDirection)
mapView.setCamera(newCamera, animated: false)
// Eugene Dudnyk's solution to help fix logic error when appending distance
sender.setTranslation(.zero, in: mapView)
} else if sender.state == .ended {
print("end")
}
}

Answer 1

The issue is that translation of pan gesture recognizer accumulates relative to the position at the start of panning, but you interpret it as accumulation since the last state change, and always add to the camera angle.
In case if user moved finger to afa.x = 160, and then moves finger back, afa.x changes let's say from 160 to 150, but you will append to the angle 150 / 30 = 5 degrees where angle has to be negative, - 10 / 30 degrees instead.
Try this, maybe it will make things better:
#objc func panMap (sender: UIPanGestureRecognizer) {
if sender.state == .began {
print("began")
} else if sender.state == .changed {
// rotating map camera
let translation = sender.translation(in: mapView)
let location = sender.location(in: mapView)
let bounds = mapView.bounds
let vector1 = CGVector(dx: location.x - bounds.midX, dy: location.y - bounds.midY)
let vector2 = CGVector(dx: vector1.dx + translation.x, dy: vector1.dy + translation.y)
let angle1 = atan2(vector1.dx, vector1.dy)
let angle2 = atan2(vector2.dx, vector2.dy)
mapView.camera.heading += (angle2 - angle1) * 180.0 / Double.pi
} else if sender.state == .ended {
print("end")
}
sender.setTranslation(.zero, in: mapView)
}