I have used UIPinchGestureRecognizer UIPanGestureRecognizer & UIRotationGestureRecognizer with UILabel to achieve Instagram like zoom and drag functionality. Now I would like to show layout guide like when UILabel is dragged in center it should show layout guide like below example. It should also display layout guide when you rotate UILabel.
What is the best and accurate possible way to achieve this functionality?
This is what I already have
(Image taken from this question by @Skiddswarmik)
Here is code I have for simple drag and zoom functionality (taken from this answer by @lbsweek)
SnapGesture Class
import UIKit
/*
usage:
add gesture:
yourObjToStoreMe.snapGesture = SnapGesture(view: your_view)
remove gesture:
yourObjToStoreMe.snapGesture = nil
disable gesture:
yourObjToStoreMe.snapGesture.isGestureEnabled = false
advanced usage:
view to receive gesture(usually superview) is different from view to be transformed,
thus you can zoom the view even if it is too small to be touched.
yourObjToStoreMe.snapGesture = SnapGesture(transformView: your_view_to_transform, gestureView: your_view_to_recieve_gesture)
*/
class SnapGesture: NSObject, UIGestureRecognizerDelegate {
// MARK: - init and deinit
convenience init(view: UIView) {
self.init(transformView: view, gestureView: view)
}
init(transformView: UIView, gestureView: UIView) {
super.init()
self.addGestures(v: gestureView)
self.weakTransformView = transformView
}
deinit {
self.cleanGesture()
}
// MARK: - private method
private weak var weakGestureView: UIView?
private weak var weakTransformView: UIView?
private var panGesture: UIPanGestureRecognizer?
private var pinchGesture: UIPinchGestureRecognizer?
private var rotationGesture: UIRotationGestureRecognizer?
private func addGestures(v: UIView) {
panGesture = UIPanGestureRecognizer(target: self, action: #selector(panProcess(_:)))
v.isUserInteractionEnabled = true
panGesture?.delegate = self // for simultaneous recog
v.addGestureRecognizer(panGesture!)
pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(pinchProcess(_:)))
//view.isUserInteractionEnabled = true
pinchGesture?.delegate = self // for simultaneous recog
v.addGestureRecognizer(pinchGesture!)
rotationGesture = UIRotationGestureRecognizer(target: self, action: #selector(rotationProcess(_:)))
rotationGesture?.delegate = self
v.addGestureRecognizer(rotationGesture!)
self.weakGestureView = v
}
private func cleanGesture() {
if let view = self.weakGestureView {
//for recognizer in view.gestureRecognizers ?? [] {
// view.removeGestureRecognizer(recognizer)
//}
if panGesture != nil {
view.removeGestureRecognizer(panGesture!)
panGesture = nil
}
if pinchGesture != nil {
view.removeGestureRecognizer(pinchGesture!)
pinchGesture = nil
}
if rotationGesture != nil {
view.removeGestureRecognizer(rotationGesture!)
rotationGesture = nil
}
}
self.weakGestureView = nil
self.weakTransformView = nil
}
// MARK: - API
private func setView(view:UIView?) {
self.setTransformView(view, gestgureView: view)
}
private func setTransformView(_ transformView: UIView?, gestgureView:UIView?) {
self.cleanGesture()
if let v = gestgureView {
self.addGestures(v: v)
}
self.weakTransformView = transformView
}
open func resetViewPosition() {
UIView.animate(withDuration: 0.4) {
self.weakTransformView?.transform = CGAffineTransform.identity
}
}
open var isGestureEnabled = true
// MARK: - gesture handle
// location will jump when finger number change
private var initPanFingerNumber:Int = 1
private var isPanFingerNumberChangedInThisSession = false
private var lastPanPoint:CGPoint = CGPoint(x: 0, y: 0)
@objc func panProcess(_ recognizer:UIPanGestureRecognizer) {
if isGestureEnabled {
//guard let view = recognizer.view else { return }
guard let view = self.weakTransformView else { return }
// init
if recognizer.state == .began {
lastPanPoint = recognizer.location(in: view)
initPanFingerNumber = recognizer.numberOfTouches
isPanFingerNumberChangedInThisSession = false
}
// judge valid
if recognizer.numberOfTouches != initPanFingerNumber {
isPanFingerNumberChangedInThisSession = true
}
if isPanFingerNumberChangedInThisSession {
return
}
// perform change
let point = recognizer.location(in: view)
view.transform = view.transform.translatedBy(x: point.x - lastPanPoint.x, y: point.y - lastPanPoint.y)
lastPanPoint = recognizer.location(in: view)
}
}
private var lastScale:CGFloat = 1.0
private var lastPinchPoint:CGPoint = CGPoint(x: 0, y: 0)
@objc func pinchProcess(_ recognizer:UIPinchGestureRecognizer) {
if isGestureEnabled {
guard let view = self.weakTransformView else { return }
// init
if recognizer.state == .began {
lastScale = 1.0;
lastPinchPoint = recognizer.location(in: view)
}
// judge valid
if recognizer.numberOfTouches < 2 {
lastPinchPoint = recognizer.location(in: view)
return
}
// Scale
let scale = 1.0 - (lastScale - recognizer.scale);
view.transform = view.transform.scaledBy(x: scale, y: scale)
lastScale = recognizer.scale;
// Translate
let point = recognizer.location(in: view)
view.transform = view.transform.translatedBy(x: point.x - lastPinchPoint.x, y: point.y - lastPinchPoint.y)
lastPinchPoint = recognizer.location(in: view)
}
}
@objc func rotationProcess(_ recognizer: UIRotationGestureRecognizer) {
if isGestureEnabled {
guard let view = self.weakTransformView else { return }
view.transform = view.transform.rotated(by: recognizer.rotation)
recognizer.rotation = 0
}
}
//MARK:- UIGestureRecognizerDelegate Methods
func gestureRecognizer(_: UIGestureRecognizer,
shouldRecognizeSimultaneouslyWith shouldRecognizeSimultaneouslyWithGestureRecognizer:UIGestureRecognizer) -> Bool {
return true
}
}
Add Gesture in
UILabel
// define
var snapGesture: SnapGesture?
// add gesture
self.snapGesture = SnapGesture(view: self.myLabel!)