From adc73fb927b696ee25662690f912f752d8d404f1 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Tue, 27 Nov 2018 23:48:07 +0900
Subject: [PATCH 01/13] change animation of overlayviewcontroller

---
 iOS Sample/iOS Sample/OverlayMenuCell.swift   | 81 +++++++++++++++----
 .../iOS Sample/OverlayViewController.swift    | 36 +++++----
 2 files changed, 83 insertions(+), 34 deletions(-)

diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index b994255..09b651f 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -27,29 +27,76 @@ import PagingKit
 
 class OverlayMenuCell: PagingMenuViewCell {
     static let sizingCell = UINib(nibName: "OverlayMenuCell", bundle: nil).instantiate(withOwner: self, options: nil).first as! OverlayMenuCell
-
+    let maskLayer: CAShapeLayer = {
+        let layer = CAShapeLayer()
+        layer.fillColor = UIColor.black.cgColor
+        return layer
+    }()
+    
+    let highlightTextLayer: CATextLayer = {
+        let layer = CATextLayer()
+        let font = UIFont.systemFont(ofSize: 16)
+        layer.font = font
+        layer.fontSize = font.pointSize
+        layer.foregroundColor = UIColor.white.cgColor
+        layer.contentsScale = UIScreen.main.scale
+        layer.alignmentMode = .center
+        return layer
+    }()
+    
+    let baseTextLayer: CATextLayer = {
+        let layer = CATextLayer()
+        let font = UIFont.systemFont(ofSize: 16)
+        layer.font = font
+        layer.fontSize = font.pointSize
+        layer.foregroundColor = UIColor.black.cgColor
+        layer.contentsScale = UIScreen.main.scale
+        layer.alignmentMode = .center
+        return layer
+    }()
+    
     @IBOutlet weak var textLabel: UILabel!
+
+    override func awakeFromNib() {
+        super.awakeFromNib()
+        textLabel.isHidden = true
+        maskLayer.isHidden = true
+        layer.addSublayer(baseTextLayer)
+        highlightTextLayer.mask = maskLayer
+        layer.addSublayer(highlightTextLayer)
+    }
     
-    var isHighlight: Bool = false {
-        didSet {
-            if isHighlight {
-                black(percent: 0)
-            } else {
-                black(percent: 1)
-            }
+    override func layoutSubviews() {
+        super.layoutSubviews()
+        if let string = highlightTextLayer.string as? NSString, let font = highlightTextLayer.font as? UIFont {
+            let stringBounds = string.boundingRect(with: CGSize(width: .max, height: .min), options: [.usesLineFragmentOrigin, .usesFontLeading], attributes: [.font: font], context: nil)
+            highlightTextLayer.frame = stringBounds
+            highlightTextLayer.frame.origin.y = (bounds.height - stringBounds.height) / 2
+            highlightTextLayer.frame.origin.x = (bounds.width - stringBounds.width) / 2
         }
+        if let string = baseTextLayer.string as? NSString, let font = baseTextLayer.font as? UIFont {
+            let stringBounds = string.boundingRect(with: CGSize(width: .max, height: .min), options: [.usesLineFragmentOrigin, .usesFontLeading], attributes: [.font: font], context: nil)
+            baseTextLayer.frame = stringBounds
+            baseTextLayer.frame.origin.y = (bounds.height - stringBounds.height) / 2
+            baseTextLayer.frame.origin.x = (bounds.width - stringBounds.width) / 2
+        }
+        
+        maskLayer.bounds = bounds.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
+        maskLayer.path = UIBezierPath(roundedRect: maskLayer.bounds, cornerRadius: bounds.height / 2).cgPath
+        
     }
     
-    func black(percent: CGFloat) {
-        let whiteRatio = 1 - percent
-        textLabel.textColor = UIColor(white: whiteRatio, alpha: 1)
+    private func layoutMaskLayer(frame: CGRect) {
+        maskLayer.frame = frame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
+        maskLayer.path = UIBezierPath(roundedRect: maskLayer.bounds, cornerRadius: bounds.height / 2).cgPath
     }
+
     
-    func highlightWithAnimation(isHighlight: Bool) {
-        UIView.transition(with: textLabel, duration: 0.4, options: .transitionCrossDissolve, animations: {
-            self.textLabel.textColor = isHighlight ? .white : .black
-        }, completion: { (_) in
-        
-        })
+    func setFocusViewFrame(frame: CGRect, from view: UIView) {
+        maskLayer.isHidden = false
+        let convertedFrame = view.layer.convert(frame, to: highlightTextLayer)
+        CATransaction.setDisableActions(true)
+        layoutMaskLayer(frame: convertedFrame)
+        CATransaction.setDisableActions(false)
     }
 }
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index f4b3809..b22d532 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -36,14 +36,16 @@ class OverlayViewController: UIViewController {
     var menuViewController: PagingMenuViewController!
     var contentViewController: PagingContentViewController!
     
+    var focusView: OverlayFocusView!
+    
     override func viewDidLoad() {
         super.viewDidLoad()
-
+        focusView = UINib(nibName: "OverlayFocusView", bundle: nil).instantiate(withOwner: self, options: nil).first as? OverlayFocusView
         menuViewController?.register(nib: UINib(nibName: "OverlayMenuCell", bundle: nil), forCellWithReuseIdentifier: "identifier")
-        menuViewController?.registerFocusView(nib: UINib(nibName: "OverlayFocusView", bundle: nil), isBehindCell: true)
-        menuViewController?.reloadData(with: 0, completionHandler: { [weak self] (_) in
-            let cell = self?.menuViewController.currentFocusedCell as? OverlayMenuCell
-            cell?.isHighlight = true
+        menuViewController?.registerFocusView(view: focusView, isBehindCell: true)
+        menuViewController?.reloadData(with: 0, completionHandler: { [weak self, focusView = focusView!] (vc) in
+            let cell = self?.menuViewController.currentFocusedCell as! OverlayMenuCell
+            cell.setFocusViewFrame(frame: focusView.frame, from: focusView)
         })
         contentViewController?.reloadData(with: 0)
     }
@@ -71,8 +73,8 @@ class OverlayViewController: UIViewController {
 extension OverlayViewController: PagingMenuViewControllerDataSource {
     func menuViewController(viewController: PagingMenuViewController, cellForItemAt index: Int) -> PagingMenuViewCell {
         let cell = viewController.dequeueReusableCell(withReuseIdentifier: "identifier", for: index)  as! OverlayMenuCell
-        cell.textLabel.text = dataSource[index].menu
-        cell.isHighlight = viewController.currentFocusedIndex == index
+        cell.highlightTextLayer.string = dataSource[index].menu
+        cell.baseTextLayer.string = dataSource[index].menu
         return cell
     }
 
@@ -103,22 +105,22 @@ extension OverlayViewController: PagingContentViewControllerDataSource {
 
 extension OverlayViewController: PagingMenuViewControllerDelegate {
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int) {
-        viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { $0.highlightWithAnimation(isHighlight: false) }
-        let selectedCell = menuViewController.cellForItem(at: page) as? OverlayMenuCell
-        selectedCell?.highlightWithAnimation(isHighlight: true)
+        viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
+            UIView.perform(.delete, on: [], options: UIView.AnimationOptions.curveEaseInOut, animations: { [viewController] in
+                cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!)
+            }, completion: nil)
+        }
         contentViewController?.scroll(to: page, animated: true)
+        
     }
 }
 
 extension OverlayViewController: PagingContentViewControllerDelegate {
     func contentViewController(viewController: PagingContentViewController, didManualScrollOn index: Int, percent: CGFloat) {
-        if percent < 0.5 {
-            let cell = menuViewController.cellForItem(at: index) as? OverlayMenuCell
-            cell?.black(percent: percent * 2)
-        } else {
-            let cell = menuViewController.cellForItem(at: index + 1) as? OverlayMenuCell
-            cell?.black(percent: (1 - percent) * 2)
-        }
         menuViewController?.scroll(index: index, percent: percent, animated: false)
+        menuViewController.visibleCells.forEach {
+            let cell = $0 as! OverlayMenuCell
+            cell.setFocusViewFrame(frame: focusView.bounds, from: focusView)
+        }
     }
 }

From b6c7973994e2e1035400751c53576a80bd12a396 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Wed, 28 Nov 2018 23:38:48 +0900
Subject: [PATCH 02/13] add select animation

---
 iOS Sample/iOS Sample/OverlayMenuCell.swift   | 37 +++++++++++++++++--
 .../iOS Sample/OverlayViewController.swift    |  8 ++--
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index 09b651f..6bbc3c9 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -92,11 +92,40 @@ class OverlayMenuCell: PagingMenuViewCell {
     }
 
     
-    func setFocusViewFrame(frame: CGRect, from view: UIView) {
+    private func animateLayoutMaskLayer(frame: CGRect, fromFrame: CGRect) {
+        let _frame = frame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
+        let _fromFrame = fromFrame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
+        
+        let positionAnimation = CABasicAnimation(keyPath: "position.x")
+        positionAnimation.fromValue = NSNumber(value: Double(_fromFrame.midX))
+        positionAnimation.toValue = NSNumber(value: Double(_frame.midX))
+        positionAnimation.duration = 0.325
+        positionAnimation.fillMode = .forwards
+        positionAnimation.isRemovedOnCompletion = false
+        positionAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
+        maskLayer.add(positionAnimation, forKey: "position.x")
+        
+        let widthAnimation = CABasicAnimation(keyPath: "bounds.size.width")
+        widthAnimation.fromValue = NSNumber(value: Double(_fromFrame.width))
+        widthAnimation.toValue = NSNumber(value: Double(_frame.width))
+        widthAnimation.duration = 0.325
+        widthAnimation.fillMode = .forwards
+        widthAnimation.isRemovedOnCompletion = false
+        widthAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
+        maskLayer.add(widthAnimation, forKey: "bounds.size.width")
+        
+    }
+    
+    func setFocusViewFrame(frame: CGRect, from view: UIView, baseView: UIView? = nil, animated: Bool) {
         maskLayer.isHidden = false
         let convertedFrame = view.layer.convert(frame, to: highlightTextLayer)
-        CATransaction.setDisableActions(true)
-        layoutMaskLayer(frame: convertedFrame)
-        CATransaction.setDisableActions(false)
+        if animated {
+            let fromFrame = baseView!.layer.convert(baseView!.layer.bounds, to: highlightTextLayer)
+            animateLayoutMaskLayer(frame: convertedFrame, fromFrame: fromFrame)
+        } else {
+            CATransaction.setDisableActions(true)
+            layoutMaskLayer(frame: convertedFrame)
+            CATransaction.setDisableActions(false)
+        }
     }
 }
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index b22d532..cbc5963 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -45,7 +45,7 @@ class OverlayViewController: UIViewController {
         menuViewController?.registerFocusView(view: focusView, isBehindCell: true)
         menuViewController?.reloadData(with: 0, completionHandler: { [weak self, focusView = focusView!] (vc) in
             let cell = self?.menuViewController.currentFocusedCell as! OverlayMenuCell
-            cell.setFocusViewFrame(frame: focusView.frame, from: focusView)
+            cell.setFocusViewFrame(frame: focusView.frame, from: focusView, animated: false)
         })
         contentViewController?.reloadData(with: 0)
     }
@@ -106,9 +106,7 @@ extension OverlayViewController: PagingContentViewControllerDataSource {
 extension OverlayViewController: PagingMenuViewControllerDelegate {
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int) {
         viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-            UIView.perform(.delete, on: [], options: UIView.AnimationOptions.curveEaseInOut, animations: { [viewController] in
-                cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!)
-            }, completion: nil)
+            cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!, baseView: viewController.cellForItem(at: previousPage)!, animated: true)
         }
         contentViewController?.scroll(to: page, animated: true)
         
@@ -120,7 +118,7 @@ extension OverlayViewController: PagingContentViewControllerDelegate {
         menuViewController?.scroll(index: index, percent: percent, animated: false)
         menuViewController.visibleCells.forEach {
             let cell = $0 as! OverlayMenuCell
-            cell.setFocusViewFrame(frame: focusView.bounds, from: focusView)
+            cell.setFocusViewFrame(frame: focusView.bounds, from: focusView, animated: false)
         }
     }
 }

From 61319f01ca34ee951a7f499566864d419ca645eb Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Thu, 29 Nov 2018 23:52:21 +0900
Subject: [PATCH 03/13] fix animation

---
 iOS Sample/iOS Sample/OverlayMenuCell.swift | 32 ++++++++++-----------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index 6bbc3c9..04a6d0c 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -93,27 +93,25 @@ class OverlayMenuCell: PagingMenuViewCell {
 
     
     private func animateLayoutMaskLayer(frame: CGRect, fromFrame: CGRect) {
-        let _frame = frame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
-        let _fromFrame = fromFrame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
-        
-        let positionAnimation = CABasicAnimation(keyPath: "position.x")
-        positionAnimation.fromValue = NSNumber(value: Double(_fromFrame.midX))
-        positionAnimation.toValue = NSNumber(value: Double(_frame.midX))
-        positionAnimation.duration = 0.325
-        positionAnimation.fillMode = .forwards
-        positionAnimation.isRemovedOnCompletion = false
+        let positionAnimation = CABasicAnimation(keyPath: "position")
+        positionAnimation.fromValue = NSValue(cgPoint: CGPoint(x: fromFrame.midX, y: fromFrame.midY)) 
+        positionAnimation.toValue = NSValue(cgPoint: CGPoint(x: frame.midX, y: frame.midY))
         positionAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
-        maskLayer.add(positionAnimation, forKey: "position.x")
         
         let widthAnimation = CABasicAnimation(keyPath: "bounds.size.width")
-        widthAnimation.fromValue = NSNumber(value: Double(_fromFrame.width))
-        widthAnimation.toValue = NSNumber(value: Double(_frame.width))
-        widthAnimation.duration = 0.325
-        widthAnimation.fillMode = .forwards
-        widthAnimation.isRemovedOnCompletion = false
-        widthAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
-        maskLayer.add(widthAnimation, forKey: "bounds.size.width")
+        widthAnimation.fromValue = NSNumber(value: Double(fromFrame.width))
+        widthAnimation.toValue = NSNumber(value: Double(frame.width))
+        positionAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
         
+        CATransaction.begin()
+        let groupAnimation = CAAnimationGroup()
+        groupAnimation.fillMode = .forwards
+        groupAnimation.isRemovedOnCompletion = false
+        groupAnimation.duration = 0.325
+        groupAnimation.animations = [positionAnimation, widthAnimation]
+        maskLayer.add(groupAnimation, forKey: "group")
+        CATransaction.commit()
+
     }
     
     func setFocusViewFrame(frame: CGRect, from view: UIView, baseView: UIView? = nil, animated: Bool) {

From 5f13183a65353269a9bc35f75affa5bae34daa3b Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Fri, 30 Nov 2018 00:07:51 +0900
Subject: [PATCH 04/13] remove Animations

---
 iOS Sample/iOS Sample/OverlayMenuCell.swift | 1 +
 1 file changed, 1 insertion(+)

diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index 04a6d0c..91e0dec 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -121,6 +121,7 @@ class OverlayMenuCell: PagingMenuViewCell {
             let fromFrame = baseView!.layer.convert(baseView!.layer.bounds, to: highlightTextLayer)
             animateLayoutMaskLayer(frame: convertedFrame, fromFrame: fromFrame)
         } else {
+            maskLayer.removeAllAnimations()
             CATransaction.setDisableActions(true)
             layoutMaskLayer(frame: convertedFrame)
             CATransaction.setDisableActions(false)

From 2dd5a77391e96b0b861365c833379f9b4e62679b Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 00:25:13 +0900
Subject: [PATCH 05/13] add animation coordinator to focusview

---
 PagingKit/PagingMenuView.swift                | 11 ++++++++++
 PagingKit/PagingMenuViewController.swift      |  8 +++++++
 iOS Sample/iOS Sample/OverlayMenuCell.swift   | 21 ++-----------------
 .../iOS Sample/OverlayViewController.swift    | 18 +++++++++++++---
 4 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/PagingKit/PagingMenuView.swift b/PagingKit/PagingMenuView.swift
index 7ccf5c5..0212e9e 100644
--- a/PagingKit/PagingMenuView.swift
+++ b/PagingKit/PagingMenuView.swift
@@ -66,6 +66,8 @@ open class PagingMenuFocusView: UIView {
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
     }
+    
+    public var coordinator: (() -> Void)?
 }
 
 /**
@@ -110,6 +112,12 @@ public protocol PagingMenuViewDelegate: class {
     ///   - pagingMenuView: The paging menu view requesting this information.
     ///   - index: The index that specifies the location of the item.
     func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int)
+    func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView)
+}
+
+public extension PagingMenuViewDelegate {
+    public func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int) {}
+    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView) {}
 }
 
 /// Displays menu lists of information and supports selection and paging of the information.
@@ -372,10 +380,13 @@ open class PagingMenuView: UIScrollView {
         focusView.selectedIndex = index
         visibleCells.selectCell(with: index)
         
+        menuDelegate?.pagingMenuView(pagingMenuView: self, willAnimate: focusView)
         UIView.perform(.delete, on: [], options: UIView.AnimationOptions(rawValue: 0), animations: { [weak self] in
             self?.contentOffset = offset
             self?.focusView.frame = itemFrame
             self?.focusView.layoutIfNeeded()
+            self?.focusView.coordinator?()
+            self?.focusView.coordinator = nil
         }, completion:completeHandler)
     }
     
diff --git a/PagingKit/PagingMenuViewController.swift b/PagingKit/PagingMenuViewController.swift
index d437624..6475927 100644
--- a/PagingKit/PagingMenuViewController.swift
+++ b/PagingKit/PagingMenuViewController.swift
@@ -41,10 +41,14 @@ public protocol PagingMenuViewControllerDelegate: class {
     ///   - page: An page number focusing the new selected menu in menu view controller.
     ///   - previousPage: An page number previously focusing menu in menu view controller.
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int)
+    
+    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView)
 }
 
 extension PagingMenuViewControllerDelegate {
     public func menuViewController(viewController: PagingMenuViewController, focusViewDidEndTransition focusView: PagingMenuFocusView) {}
+    
+    public func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView) {}
 }
 
 /// The data source provides the paging menu view controller object with the information it needs to construct and modify the menus.
@@ -298,6 +302,10 @@ extension PagingMenuViewController: UIScrollViewDelegate {
 // MARK:- PagingMenuViewDelegate
 
 extension PagingMenuViewController: PagingMenuViewDelegate {
+    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView) {
+        delegate?.menuViewController(viewController: self, willAnimate: focusView)
+    }
+    
     public func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int) {
         guard menuView.focusView.selectedIndex != index else { return }
         
diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index 91e0dec..ec66e70 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -93,25 +93,8 @@ class OverlayMenuCell: PagingMenuViewCell {
 
     
     private func animateLayoutMaskLayer(frame: CGRect, fromFrame: CGRect) {
-        let positionAnimation = CABasicAnimation(keyPath: "position")
-        positionAnimation.fromValue = NSValue(cgPoint: CGPoint(x: fromFrame.midX, y: fromFrame.midY)) 
-        positionAnimation.toValue = NSValue(cgPoint: CGPoint(x: frame.midX, y: frame.midY))
-        positionAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
-        
-        let widthAnimation = CABasicAnimation(keyPath: "bounds.size.width")
-        widthAnimation.fromValue = NSNumber(value: Double(fromFrame.width))
-        widthAnimation.toValue = NSNumber(value: Double(frame.width))
-        positionAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
-        
-        CATransaction.begin()
-        let groupAnimation = CAAnimationGroup()
-        groupAnimation.fillMode = .forwards
-        groupAnimation.isRemovedOnCompletion = false
-        groupAnimation.duration = 0.325
-        groupAnimation.animations = [positionAnimation, widthAnimation]
-        maskLayer.add(groupAnimation, forKey: "group")
-        CATransaction.commit()
-
+        maskLayer.position = CGPoint(x: frame.midX, y: frame.midY)
+        maskLayer.bounds.size.width = frame.width
     }
     
     func setFocusViewFrame(frame: CGRect, from view: UIView, baseView: UIView? = nil, animated: Bool) {
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index cbc5963..46dd36e 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -68,6 +68,9 @@ class OverlayViewController: UIViewController {
         }
     }
 
+    
+    var page: Int?
+    var prevPage: Int?
 }
 
 extension OverlayViewController: PagingMenuViewControllerDataSource {
@@ -105,12 +108,21 @@ extension OverlayViewController: PagingContentViewControllerDataSource {
 
 extension OverlayViewController: PagingMenuViewControllerDelegate {
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int) {
-        viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-            cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!, baseView: viewController.cellForItem(at: previousPage)!, animated: true)
-        }
+        self.page = page
+        self.prevPage = previousPage
         contentViewController?.scroll(to: page, animated: true)
         
     }
+    
+    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView) {
+        focusView.coordinator = { [page = self.page!, prevPage = self.prevPage!] in
+            viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
+                cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!, baseView: viewController.cellForItem(at: prevPage)!, animated: true)
+            }
+        }
+        page = nil
+        prevPage = nil
+    }
 }
 
 extension OverlayViewController: PagingContentViewControllerDelegate {

From 6cb4001ce6afbcadb8b96d2b3f22fbb3b0440991 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 00:36:33 +0900
Subject: [PATCH 06/13] fix animation

---
 iOS Sample/iOS Sample/OverlayMenuCell.swift   | 21 +++++--------------
 .../iOS Sample/OverlayViewController.swift    | 10 ++++-----
 2 files changed, 10 insertions(+), 21 deletions(-)

diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index ec66e70..8a42850 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -90,24 +90,13 @@ class OverlayMenuCell: PagingMenuViewCell {
         maskLayer.frame = frame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
         maskLayer.path = UIBezierPath(roundedRect: maskLayer.bounds, cornerRadius: bounds.height / 2).cgPath
     }
-
-    
-    private func animateLayoutMaskLayer(frame: CGRect, fromFrame: CGRect) {
-        maskLayer.position = CGPoint(x: frame.midX, y: frame.midY)
-        maskLayer.bounds.size.width = frame.width
-    }
     
-    func setFocusViewFrame(frame: CGRect, from view: UIView, baseView: UIView? = nil, animated: Bool) {
+    func setFocusViewFrame(frame: CGRect, from view: UIView, animated: Bool) {
         maskLayer.isHidden = false
         let convertedFrame = view.layer.convert(frame, to: highlightTextLayer)
-        if animated {
-            let fromFrame = baseView!.layer.convert(baseView!.layer.bounds, to: highlightTextLayer)
-            animateLayoutMaskLayer(frame: convertedFrame, fromFrame: fromFrame)
-        } else {
-            maskLayer.removeAllAnimations()
-            CATransaction.setDisableActions(true)
-            layoutMaskLayer(frame: convertedFrame)
-            CATransaction.setDisableActions(false)
-        }
+        
+        CATransaction.setDisableActions(!animated)
+        layoutMaskLayer(frame: convertedFrame)
+        CATransaction.setDisableActions(false)
     }
 }
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index 46dd36e..f1bdf30 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -70,7 +70,6 @@ class OverlayViewController: UIViewController {
 
     
     var page: Int?
-    var prevPage: Int?
 }
 
 extension OverlayViewController: PagingMenuViewControllerDataSource {
@@ -78,6 +77,9 @@ extension OverlayViewController: PagingMenuViewControllerDataSource {
         let cell = viewController.dequeueReusableCell(withReuseIdentifier: "identifier", for: index)  as! OverlayMenuCell
         cell.highlightTextLayer.string = dataSource[index].menu
         cell.baseTextLayer.string = dataSource[index].menu
+        if let focusedCell = viewController.currentFocusedCell {
+            cell.setFocusViewFrame(frame: focusedCell.frame, from: focusedCell, animated: false)
+        }
         return cell
     }
 
@@ -109,19 +111,17 @@ extension OverlayViewController: PagingContentViewControllerDataSource {
 extension OverlayViewController: PagingMenuViewControllerDelegate {
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int) {
         self.page = page
-        self.prevPage = previousPage
         contentViewController?.scroll(to: page, animated: true)
         
     }
     
     func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView) {
-        focusView.coordinator = { [page = self.page!, prevPage = self.prevPage!] in
+        focusView.coordinator = { [page = self.page!] in
             viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-                cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!, baseView: viewController.cellForItem(at: prevPage)!, animated: true)
+                cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!, animated: true)
             }
         }
         page = nil
-        prevPage = nil
     }
 }
 

From 3c922d2e4c847053c025942e3bf9bc57e9bb51ec Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 00:41:19 +0900
Subject: [PATCH 07/13] removed state

---
 PagingKit/PagingMenuView.swift                    |  6 +++---
 PagingKit/PagingMenuViewController.swift          |  8 ++++----
 iOS Sample/iOS Sample/OverlayViewController.swift | 12 ++++--------
 3 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/PagingKit/PagingMenuView.swift b/PagingKit/PagingMenuView.swift
index 0212e9e..c3cb40f 100644
--- a/PagingKit/PagingMenuView.swift
+++ b/PagingKit/PagingMenuView.swift
@@ -112,12 +112,12 @@ public protocol PagingMenuViewDelegate: class {
     ///   - pagingMenuView: The paging menu view requesting this information.
     ///   - index: The index that specifies the location of the item.
     func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int)
-    func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView)
+    func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView, at index: Int)
 }
 
 public extension PagingMenuViewDelegate {
     public func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int) {}
-    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView) {}
+    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView, at index: Int) {}
 }
 
 /// Displays menu lists of information and supports selection and paging of the information.
@@ -380,7 +380,7 @@ open class PagingMenuView: UIScrollView {
         focusView.selectedIndex = index
         visibleCells.selectCell(with: index)
         
-        menuDelegate?.pagingMenuView(pagingMenuView: self, willAnimate: focusView)
+        menuDelegate?.pagingMenuView(pagingMenuView: self, willAnimate: focusView, at: index)
         UIView.perform(.delete, on: [], options: UIView.AnimationOptions(rawValue: 0), animations: { [weak self] in
             self?.contentOffset = offset
             self?.focusView.frame = itemFrame
diff --git a/PagingKit/PagingMenuViewController.swift b/PagingKit/PagingMenuViewController.swift
index 6475927..8e7ef7f 100644
--- a/PagingKit/PagingMenuViewController.swift
+++ b/PagingKit/PagingMenuViewController.swift
@@ -42,13 +42,13 @@ public protocol PagingMenuViewControllerDelegate: class {
     ///   - previousPage: An page number previously focusing menu in menu view controller.
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int)
     
-    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView)
+    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int)
 }
 
 extension PagingMenuViewControllerDelegate {
     public func menuViewController(viewController: PagingMenuViewController, focusViewDidEndTransition focusView: PagingMenuFocusView) {}
     
-    public func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView) {}
+    public func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int) {}
 }
 
 /// The data source provides the paging menu view controller object with the information it needs to construct and modify the menus.
@@ -302,8 +302,8 @@ extension PagingMenuViewController: UIScrollViewDelegate {
 // MARK:- PagingMenuViewDelegate
 
 extension PagingMenuViewController: PagingMenuViewDelegate {
-    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView) {
-        delegate?.menuViewController(viewController: self, willAnimate: focusView)
+    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView, at index: Int) {
+        delegate?.menuViewController(viewController: self, willAnimate: focusView, at: index)
     }
     
     public func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int) {
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index f1bdf30..c240edf 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -67,9 +67,6 @@ class OverlayViewController: UIViewController {
             contentViewController?.dataSource = self
         }
     }
-
-    
-    var page: Int?
 }
 
 extension OverlayViewController: PagingMenuViewControllerDataSource {
@@ -110,18 +107,17 @@ extension OverlayViewController: PagingContentViewControllerDataSource {
 
 extension OverlayViewController: PagingMenuViewControllerDelegate {
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int) {
-        self.page = page
         contentViewController?.scroll(to: page, animated: true)
         
     }
     
-    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView) {
-        focusView.coordinator = { [page = self.page!] in
+    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int) {
+        guard let nextCell = viewController.cellForItem(at: index) else { return }
+        focusView.coordinator = {
             viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-                cell.setFocusViewFrame(frame: viewController.cellForItem(at: page)!.bounds, from: viewController.cellForItem(at: page)!, animated: true)
+                cell.setFocusViewFrame(frame: nextCell.bounds, from: nextCell, animated: true)
             }
         }
-        page = nil
     }
 }
 

From 6efe2188126cff2ed651bc4974544f1b6314c088 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 00:50:11 +0900
Subject: [PATCH 08/13] add animaation coordinator

---
 PagingKit/PagingMenuView.swift                | 22 ++++++++++++++++---
 .../iOS Sample/OverlayViewController.swift    |  4 ++--
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/PagingKit/PagingMenuView.swift b/PagingKit/PagingMenuView.swift
index c3cb40f..a024430 100644
--- a/PagingKit/PagingMenuView.swift
+++ b/PagingKit/PagingMenuView.swift
@@ -54,6 +54,16 @@ open class PagingMenuViewCell: UIView {
     public internal(set) var index: Int!
 }
 
+open class PagingMenuFocusViewAnimationCoordinator {
+    fileprivate var animationHandler: ((PagingMenuFocusViewAnimationCoordinator) -> Void)?
+    fileprivate var completionHandler: ((Bool) -> Void)?
+    
+    open func animateFocusView(alongside animation: @escaping (PagingMenuFocusViewAnimationCoordinator) -> Void, completion: ((Bool) -> Void)?) {
+        animationHandler = animation
+        completionHandler = completion
+    }
+}
+
 /// A view that focus menu corresponding to current page.
 open class PagingMenuFocusView: UIView {
     open var selectedIndex: Int?
@@ -67,7 +77,7 @@ open class PagingMenuFocusView: UIView {
         super.init(coder: aDecoder)
     }
     
-    public var coordinator: (() -> Void)?
+    open var coordinator: PagingMenuFocusViewAnimationCoordinator?
 }
 
 /**
@@ -380,14 +390,20 @@ open class PagingMenuView: UIScrollView {
         focusView.selectedIndex = index
         visibleCells.selectCell(with: index)
         
+        focusView.coordinator = PagingMenuFocusViewAnimationCoordinator()
         menuDelegate?.pagingMenuView(pagingMenuView: self, willAnimate: focusView, at: index)
         UIView.perform(.delete, on: [], options: UIView.AnimationOptions(rawValue: 0), animations: { [weak self] in
             self?.contentOffset = offset
             self?.focusView.frame = itemFrame
             self?.focusView.layoutIfNeeded()
-            self?.focusView.coordinator?()
+            if let coordinator = self?.focusView.coordinator {
+                coordinator.animationHandler?(coordinator)
+            }
+        }, completion: { [weak self] (finished) in
+            self?.focusView.coordinator?.completionHandler?(finished)
             self?.focusView.coordinator = nil
-        }, completion:completeHandler)
+            completeHandler(finished)
+        })
     }
     
     // MARK:- Internal
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index c240edf..988d012 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -113,11 +113,11 @@ extension OverlayViewController: PagingMenuViewControllerDelegate {
     
     func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int) {
         guard let nextCell = viewController.cellForItem(at: index) else { return }
-        focusView.coordinator = {
+        focusView.coordinator?.animateFocusView(alongside: { _ in
             viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
                 cell.setFocusViewFrame(frame: nextCell.bounds, from: nextCell, animated: true)
             }
-        }
+        }, completion: nil)
     }
 }
 

From 2e7f81a391df565bc4d5ed6e107da210a41b211e Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 00:54:59 +0900
Subject: [PATCH 09/13] change interface

---
 iOS Sample/iOS Sample/OverlayMenuCell.swift       |  4 ++--
 iOS Sample/iOS Sample/OverlayViewController.swift | 12 +++++-------
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index 8a42850..aa0bfb0 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -91,9 +91,9 @@ class OverlayMenuCell: PagingMenuViewCell {
         maskLayer.path = UIBezierPath(roundedRect: maskLayer.bounds, cornerRadius: bounds.height / 2).cgPath
     }
     
-    func setFocusViewFrame(frame: CGRect, from view: UIView, animated: Bool) {
+    func setFrame(_ view: UIView, animated: Bool) {
         maskLayer.isHidden = false
-        let convertedFrame = view.layer.convert(frame, to: highlightTextLayer)
+        let convertedFrame = view.layer.convert(view.bounds, to: highlightTextLayer)
         
         CATransaction.setDisableActions(!animated)
         layoutMaskLayer(frame: convertedFrame)
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index 988d012..b411e11 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -43,9 +43,9 @@ class OverlayViewController: UIViewController {
         focusView = UINib(nibName: "OverlayFocusView", bundle: nil).instantiate(withOwner: self, options: nil).first as? OverlayFocusView
         menuViewController?.register(nib: UINib(nibName: "OverlayMenuCell", bundle: nil), forCellWithReuseIdentifier: "identifier")
         menuViewController?.registerFocusView(view: focusView, isBehindCell: true)
-        menuViewController?.reloadData(with: 0, completionHandler: { [weak self, focusView = focusView!] (vc) in
+        menuViewController?.reloadData(with: 0, completionHandler: { [weak self, menuViewController = menuViewController!] (vc) in
             let cell = self?.menuViewController.currentFocusedCell as! OverlayMenuCell
-            cell.setFocusViewFrame(frame: focusView.frame, from: focusView, animated: false)
+            cell.setFrame(menuViewController.focusView, animated: false)
         })
         contentViewController?.reloadData(with: 0)
     }
@@ -74,9 +74,7 @@ extension OverlayViewController: PagingMenuViewControllerDataSource {
         let cell = viewController.dequeueReusableCell(withReuseIdentifier: "identifier", for: index)  as! OverlayMenuCell
         cell.highlightTextLayer.string = dataSource[index].menu
         cell.baseTextLayer.string = dataSource[index].menu
-        if let focusedCell = viewController.currentFocusedCell {
-            cell.setFocusViewFrame(frame: focusedCell.frame, from: focusedCell, animated: false)
-        }
+        cell.setFrame(viewController.focusView, animated: false)
         return cell
     }
 
@@ -115,7 +113,7 @@ extension OverlayViewController: PagingMenuViewControllerDelegate {
         guard let nextCell = viewController.cellForItem(at: index) else { return }
         focusView.coordinator?.animateFocusView(alongside: { _ in
             viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-                cell.setFocusViewFrame(frame: nextCell.bounds, from: nextCell, animated: true)
+                cell.setFrame(nextCell, animated: true)
             }
         }, completion: nil)
     }
@@ -126,7 +124,7 @@ extension OverlayViewController: PagingContentViewControllerDelegate {
         menuViewController?.scroll(index: index, percent: percent, animated: false)
         menuViewController.visibleCells.forEach {
             let cell = $0 as! OverlayMenuCell
-            cell.setFocusViewFrame(frame: focusView.bounds, from: focusView, animated: false)
+            cell.setFrame(focusView, animated: false)
         }
     }
 }

From 2a229656c94c9bd8febd65c141e13269e3bdb612 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 11:00:53 +0900
Subject: [PATCH 10/13] change layer to view

---
 PagingKit/PagingMenuView.swift                | 10 ++-
 iOS Sample/iOS Sample/OverlayMenuCell.swift   | 89 +++++++++----------
 .../iOS Sample/OverlayViewController.swift    | 28 +++---
 3 files changed, 66 insertions(+), 61 deletions(-)

diff --git a/PagingKit/PagingMenuView.swift b/PagingKit/PagingMenuView.swift
index a024430..b29a033 100644
--- a/PagingKit/PagingMenuView.swift
+++ b/PagingKit/PagingMenuView.swift
@@ -55,9 +55,17 @@ open class PagingMenuViewCell: UIView {
 }
 
 open class PagingMenuFocusViewAnimationCoordinator {
+    public let beginFrame: CGRect
+    public let endFrame: CGRect
+    
     fileprivate var animationHandler: ((PagingMenuFocusViewAnimationCoordinator) -> Void)?
     fileprivate var completionHandler: ((Bool) -> Void)?
     
+    init(beginFrame: CGRect, endFrame: CGRect) {
+        self.beginFrame = beginFrame
+        self.endFrame = endFrame
+    }
+    
     open func animateFocusView(alongside animation: @escaping (PagingMenuFocusViewAnimationCoordinator) -> Void, completion: ((Bool) -> Void)?) {
         animationHandler = animation
         completionHandler = completion
@@ -390,7 +398,7 @@ open class PagingMenuView: UIScrollView {
         focusView.selectedIndex = index
         visibleCells.selectCell(with: index)
         
-        focusView.coordinator = PagingMenuFocusViewAnimationCoordinator()
+        focusView.coordinator = PagingMenuFocusViewAnimationCoordinator(beginFrame: focusView.frame, endFrame: itemFrame)
         menuDelegate?.pagingMenuView(pagingMenuView: self, willAnimate: focusView, at: index)
         UIView.perform(.delete, on: [], options: UIView.AnimationOptions(rawValue: 0), animations: { [weak self] in
             self?.contentOffset = offset
diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index aa0bfb0..297d639 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -27,32 +27,29 @@ import PagingKit
 
 class OverlayMenuCell: PagingMenuViewCell {
     static let sizingCell = UINib(nibName: "OverlayMenuCell", bundle: nil).instantiate(withOwner: self, options: nil).first as! OverlayMenuCell
-    let maskLayer: CAShapeLayer = {
-        let layer = CAShapeLayer()
-        layer.fillColor = UIColor.black.cgColor
-        return layer
+    
+    let textMaskView: UIView = {
+        let view = UIView()
+        view.backgroundColor = .black
+        return view
     }()
     
-    let highlightTextLayer: CATextLayer = {
-        let layer = CATextLayer()
-        let font = UIFont.systemFont(ofSize: 16)
-        layer.font = font
-        layer.fontSize = font.pointSize
-        layer.foregroundColor = UIColor.white.cgColor
-        layer.contentsScale = UIScreen.main.scale
-        layer.alignmentMode = .center
-        return layer
+    let highlightLabel: UILabel = {
+        let label = UILabel()
+        label.translatesAutoresizingMaskIntoConstraints = false
+        label.font = UIFont.systemFont(ofSize: 16)
+        label.textColor = UIColor.white
+        label.textAlignment = .center
+        return label
     }()
     
-    let baseTextLayer: CATextLayer = {
-        let layer = CATextLayer()
-        let font = UIFont.systemFont(ofSize: 16)
-        layer.font = font
-        layer.fontSize = font.pointSize
-        layer.foregroundColor = UIColor.black.cgColor
-        layer.contentsScale = UIScreen.main.scale
-        layer.alignmentMode = .center
-        return layer
+    let titleLabel: UILabel = {
+        let label = UILabel()
+        label.translatesAutoresizingMaskIntoConstraints = false
+        label.font = UIFont.systemFont(ofSize: 16)
+        label.textColor = UIColor.black
+        label.textAlignment = .center
+        return label
     }()
     
     @IBOutlet weak var textLabel: UILabel!
@@ -60,40 +57,38 @@ class OverlayMenuCell: PagingMenuViewCell {
     override func awakeFromNib() {
         super.awakeFromNib()
         textLabel.isHidden = true
-        maskLayer.isHidden = true
-        layer.addSublayer(baseTextLayer)
-        highlightTextLayer.mask = maskLayer
-        layer.addSublayer(highlightTextLayer)
+        addSubview(titleLabel)
+        highlightLabel.mask = textMaskView
+        addSubview(highlightLabel)
+        
+        do {
+            titleLabel.topAnchor.constraint(equalTo: topAnchor).isActive = true
+            titleLabel.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
+            titleLabel.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
+            titleLabel.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
+        }
+        
+        do {
+            highlightLabel.topAnchor.constraint(equalTo: topAnchor).isActive = true
+            highlightLabel.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
+            highlightLabel.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
+            highlightLabel.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
+        }
     }
     
     override func layoutSubviews() {
         super.layoutSubviews()
-        if let string = highlightTextLayer.string as? NSString, let font = highlightTextLayer.font as? UIFont {
-            let stringBounds = string.boundingRect(with: CGSize(width: .max, height: .min), options: [.usesLineFragmentOrigin, .usesFontLeading], attributes: [.font: font], context: nil)
-            highlightTextLayer.frame = stringBounds
-            highlightTextLayer.frame.origin.y = (bounds.height - stringBounds.height) / 2
-            highlightTextLayer.frame.origin.x = (bounds.width - stringBounds.width) / 2
-        }
-        if let string = baseTextLayer.string as? NSString, let font = baseTextLayer.font as? UIFont {
-            let stringBounds = string.boundingRect(with: CGSize(width: .max, height: .min), options: [.usesLineFragmentOrigin, .usesFontLeading], attributes: [.font: font], context: nil)
-            baseTextLayer.frame = stringBounds
-            baseTextLayer.frame.origin.y = (bounds.height - stringBounds.height) / 2
-            baseTextLayer.frame.origin.x = (bounds.width - stringBounds.width) / 2
-        }
-        
-        maskLayer.bounds = bounds.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
-        maskLayer.path = UIBezierPath(roundedRect: maskLayer.bounds, cornerRadius: bounds.height / 2).cgPath
-        
+        textMaskView.bounds = bounds.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
     }
     
     private func layoutMaskLayer(frame: CGRect) {
-        maskLayer.frame = frame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
-        maskLayer.path = UIBezierPath(roundedRect: maskLayer.bounds, cornerRadius: bounds.height / 2).cgPath
+        textMaskView.frame = frame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
     }
     
-    func setFrame(_ view: UIView, animated: Bool) {
-        maskLayer.isHidden = false
-        let convertedFrame = view.layer.convert(view.bounds, to: highlightTextLayer)
+    
+    func setFrame(_ view: UIView, frame: CGRect, animated: Bool) {
+        textMaskView.isHidden = false
+        let convertedFrame = view.convert(frame, to: highlightLabel)
         
         CATransaction.setDisableActions(!animated)
         layoutMaskLayer(frame: convertedFrame)
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index b411e11..cdbee40 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -36,16 +36,13 @@ class OverlayViewController: UIViewController {
     var menuViewController: PagingMenuViewController!
     var contentViewController: PagingContentViewController!
     
-    var focusView: OverlayFocusView!
-    
     override func viewDidLoad() {
         super.viewDidLoad()
-        focusView = UINib(nibName: "OverlayFocusView", bundle: nil).instantiate(withOwner: self, options: nil).first as? OverlayFocusView
         menuViewController?.register(nib: UINib(nibName: "OverlayMenuCell", bundle: nil), forCellWithReuseIdentifier: "identifier")
-        menuViewController?.registerFocusView(view: focusView, isBehindCell: true)
+        menuViewController?.registerFocusView(nib: UINib(nibName: "OverlayFocusView", bundle: nil), isBehindCell: true)
         menuViewController?.reloadData(with: 0, completionHandler: { [weak self, menuViewController = menuViewController!] (vc) in
             let cell = self?.menuViewController.currentFocusedCell as! OverlayMenuCell
-            cell.setFrame(menuViewController.focusView, animated: false)
+            cell.setFrame(menuViewController.menuView, frame: menuViewController.focusView.frame, animated: false)
         })
         contentViewController?.reloadData(with: 0)
     }
@@ -72,9 +69,9 @@ class OverlayViewController: UIViewController {
 extension OverlayViewController: PagingMenuViewControllerDataSource {
     func menuViewController(viewController: PagingMenuViewController, cellForItemAt index: Int) -> PagingMenuViewCell {
         let cell = viewController.dequeueReusableCell(withReuseIdentifier: "identifier", for: index)  as! OverlayMenuCell
-        cell.highlightTextLayer.string = dataSource[index].menu
-        cell.baseTextLayer.string = dataSource[index].menu
-        cell.setFrame(viewController.focusView, animated: false)
+        cell.titleLabel.text = dataSource[index].menu
+        cell.highlightLabel.text = dataSource[index].menu
+        cell.setFrame(viewController.menuView, frame: cell.frame, animated: false)
         return cell
     }
 
@@ -110,10 +107,15 @@ extension OverlayViewController: PagingMenuViewControllerDelegate {
     }
     
     func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int) {
-        guard let nextCell = viewController.cellForItem(at: index) else { return }
-        focusView.coordinator?.animateFocusView(alongside: { _ in
+        guard let coordinator = focusView.coordinator else { return }
+        
+        viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
+            cell.setFrame(viewController.menuView, frame: coordinator.beginFrame, animated: true)
+        }
+        
+        coordinator.animateFocusView(alongside: { coordinator in
             viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-                cell.setFrame(nextCell, animated: true)
+                cell.setFrame(viewController.menuView, frame: coordinator.endFrame, animated: true)
             }
         }, completion: nil)
     }
@@ -121,10 +123,10 @@ extension OverlayViewController: PagingMenuViewControllerDelegate {
 
 extension OverlayViewController: PagingContentViewControllerDelegate {
     func contentViewController(viewController: PagingContentViewController, didManualScrollOn index: Int, percent: CGFloat) {
-        menuViewController?.scroll(index: index, percent: percent, animated: false)
+        menuViewController.scroll(index: index, percent: percent, animated: false)
         menuViewController.visibleCells.forEach {
             let cell = $0 as! OverlayMenuCell
-            cell.setFrame(focusView, animated: false)
+            cell.setFrame(menuViewController.menuView, frame: menuViewController.focusView.frame, animated: false)
         }
     }
 }

From 5d19a3b6026fd6011e4cee92bf18edbbf65301b4 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 11:10:22 +0900
Subject: [PATCH 11/13] simplified  sample code

---
 iOS Sample/iOS Sample/OverlayMenuCell.swift   | 56 +++----------------
 iOS Sample/iOS Sample/OverlayMenuCell.xib     | 17 +++++-
 .../iOS Sample/OverlayViewController.swift    | 12 ++--
 3 files changed, 27 insertions(+), 58 deletions(-)

diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.swift b/iOS Sample/iOS Sample/OverlayMenuCell.swift
index 297d639..3e4e1f5 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.swift	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.swift	
@@ -28,70 +28,28 @@ import PagingKit
 class OverlayMenuCell: PagingMenuViewCell {
     static let sizingCell = UINib(nibName: "OverlayMenuCell", bundle: nil).instantiate(withOwner: self, options: nil).first as! OverlayMenuCell
     
+    let maskInsets = UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8)
+    
     let textMaskView: UIView = {
         let view = UIView()
         view.backgroundColor = .black
         return view
     }()
     
-    let highlightLabel: UILabel = {
-        let label = UILabel()
-        label.translatesAutoresizingMaskIntoConstraints = false
-        label.font = UIFont.systemFont(ofSize: 16)
-        label.textColor = UIColor.white
-        label.textAlignment = .center
-        return label
-    }()
-    
-    let titleLabel: UILabel = {
-        let label = UILabel()
-        label.translatesAutoresizingMaskIntoConstraints = false
-        label.font = UIFont.systemFont(ofSize: 16)
-        label.textColor = UIColor.black
-        label.textAlignment = .center
-        return label
-    }()
-    
-    @IBOutlet weak var textLabel: UILabel!
+    @IBOutlet var highlightLabel: UILabel!
+    @IBOutlet var titleLabel: UILabel!    
 
     override func awakeFromNib() {
         super.awakeFromNib()
-        textLabel.isHidden = true
-        addSubview(titleLabel)
         highlightLabel.mask = textMaskView
-        addSubview(highlightLabel)
-        
-        do {
-            titleLabel.topAnchor.constraint(equalTo: topAnchor).isActive = true
-            titleLabel.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
-            titleLabel.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
-            titleLabel.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
-        }
-        
-        do {
-            highlightLabel.topAnchor.constraint(equalTo: topAnchor).isActive = true
-            highlightLabel.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
-            highlightLabel.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
-            highlightLabel.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
-        }
     }
     
     override func layoutSubviews() {
         super.layoutSubviews()
-        textMaskView.bounds = bounds.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
-    }
-    
-    private func layoutMaskLayer(frame: CGRect) {
-        textMaskView.frame = frame.inset(by: UIEdgeInsets(top: 6, left: 8, bottom: 6, right: 8))
+        textMaskView.bounds = bounds.inset(by: maskInsets)
     }
     
-    
-    func setFrame(_ view: UIView, frame: CGRect, animated: Bool) {
-        textMaskView.isHidden = false
-        let convertedFrame = view.convert(frame, to: highlightLabel)
-        
-        CATransaction.setDisableActions(!animated)
-        layoutMaskLayer(frame: convertedFrame)
-        CATransaction.setDisableActions(false)
+    func setFrame(_ menuView: PagingMenuView, maskFrame: CGRect, animated: Bool) {
+        textMaskView.frame = menuView.convert(maskFrame, to: highlightLabel).inset(by: maskInsets)
     }
 }
diff --git a/iOS Sample/iOS Sample/OverlayMenuCell.xib b/iOS Sample/iOS Sample/OverlayMenuCell.xib
index cb2109a..436dd97 100644
--- a/iOS Sample/iOS Sample/OverlayMenuCell.xib	
+++ b/iOS Sample/iOS Sample/OverlayMenuCell.xib	
@@ -1,11 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="12120" systemVersion="16E195" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="14460.31" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES">
     <device id="retina4_7" orientation="portrait">
         <adaptation id="fullscreen"/>
     </device>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12088"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14460.20"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -21,9 +21,19 @@
                     <nil key="textColor"/>
                     <nil key="highlightedColor"/>
                 </label>
+                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Label" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="rXC-N4-4ky">
+                    <rect key="frame" x="16" y="8" width="241" height="31"/>
+                    <fontDescription key="fontDescription" type="system" pointSize="17"/>
+                    <color key="textColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                    <nil key="highlightedColor"/>
+                </label>
             </subviews>
             <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="calibratedWhite"/>
             <constraints>
+                <constraint firstItem="rXC-N4-4ky" firstAttribute="top" secondItem="UfI-M3-AT8" secondAttribute="top" constant="8" id="987-XZ-nJb"/>
+                <constraint firstAttribute="bottom" secondItem="rXC-N4-4ky" secondAttribute="bottom" constant="8" id="Pg7-Jd-4w4"/>
+                <constraint firstItem="rXC-N4-4ky" firstAttribute="leading" secondItem="UfI-M3-AT8" secondAttribute="leading" constant="16" id="VWa-qv-U0l"/>
+                <constraint firstAttribute="trailing" secondItem="rXC-N4-4ky" secondAttribute="trailing" constant="16" id="e68-bs-8dj"/>
                 <constraint firstAttribute="trailing" secondItem="IQt-N5-kx9" secondAttribute="trailing" constant="16" id="uET-X1-Oe0"/>
                 <constraint firstAttribute="bottom" secondItem="IQt-N5-kx9" secondAttribute="bottom" constant="8" id="vKh-VV-Fr3"/>
                 <constraint firstItem="IQt-N5-kx9" firstAttribute="top" secondItem="UfI-M3-AT8" secondAttribute="top" constant="8" id="xEX-Z0-xha"/>
@@ -31,7 +41,8 @@
             </constraints>
             <freeformSimulatedSizeMetrics key="simulatedDestinationMetrics"/>
             <connections>
-                <outlet property="textLabel" destination="IQt-N5-kx9" id="0GA-wf-lBT"/>
+                <outlet property="highlightLabel" destination="rXC-N4-4ky" id="zMg-8O-9y4"/>
+                <outlet property="titleLabel" destination="IQt-N5-kx9" id="tym-Vc-Zsn"/>
             </connections>
             <point key="canvasLocation" x="145.5" y="-54.5"/>
         </view>
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index cdbee40..46d1254 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -42,7 +42,7 @@ class OverlayViewController: UIViewController {
         menuViewController?.registerFocusView(nib: UINib(nibName: "OverlayFocusView", bundle: nil), isBehindCell: true)
         menuViewController?.reloadData(with: 0, completionHandler: { [weak self, menuViewController = menuViewController!] (vc) in
             let cell = self?.menuViewController.currentFocusedCell as! OverlayMenuCell
-            cell.setFrame(menuViewController.menuView, frame: menuViewController.focusView.frame, animated: false)
+            cell.setFrame(menuViewController.menuView, maskFrame: menuViewController.focusView.frame, animated: false)
         })
         contentViewController?.reloadData(with: 0)
     }
@@ -71,13 +71,13 @@ extension OverlayViewController: PagingMenuViewControllerDataSource {
         let cell = viewController.dequeueReusableCell(withReuseIdentifier: "identifier", for: index)  as! OverlayMenuCell
         cell.titleLabel.text = dataSource[index].menu
         cell.highlightLabel.text = dataSource[index].menu
-        cell.setFrame(viewController.menuView, frame: cell.frame, animated: false)
+        cell.setFrame(viewController.menuView, maskFrame: cell.frame, animated: false)
         return cell
     }
 
     
     func menuViewController(viewController: PagingMenuViewController, widthForItemAt index: Int) -> CGFloat {
-        OverlayMenuCell.sizingCell.textLabel.text = dataSource[index].menu
+        OverlayMenuCell.sizingCell.titleLabel.text = dataSource[index].menu
         var referenceSize = UIView.layoutFittingCompressedSize
         referenceSize.height = viewController.view.bounds.height
         let size = OverlayMenuCell.sizingCell.systemLayoutSizeFitting(referenceSize, withHorizontalFittingPriority: UILayoutPriority.defaultLow, verticalFittingPriority: UILayoutPriority.defaultHigh)
@@ -110,12 +110,12 @@ extension OverlayViewController: PagingMenuViewControllerDelegate {
         guard let coordinator = focusView.coordinator else { return }
         
         viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-            cell.setFrame(viewController.menuView, frame: coordinator.beginFrame, animated: true)
+            cell.setFrame(viewController.menuView, maskFrame: coordinator.beginFrame, animated: true)
         }
         
         coordinator.animateFocusView(alongside: { coordinator in
             viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
-                cell.setFrame(viewController.menuView, frame: coordinator.endFrame, animated: true)
+                cell.setFrame(viewController.menuView, maskFrame: coordinator.endFrame, animated: true)
             }
         }, completion: nil)
     }
@@ -126,7 +126,7 @@ extension OverlayViewController: PagingContentViewControllerDelegate {
         menuViewController.scroll(index: index, percent: percent, animated: false)
         menuViewController.visibleCells.forEach {
             let cell = $0 as! OverlayMenuCell
-            cell.setFrame(menuViewController.menuView, frame: menuViewController.focusView.frame, animated: false)
+            cell.setFrame(menuViewController.menuView, maskFrame: menuViewController.focusView.frame, animated: false)
         }
     }
 }

From 88c67bbf878edf6bf2a8148860ab08a717340762 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 11:24:15 +0900
Subject: [PATCH 12/13] add documantation

---
 PagingKit/PagingMenuView.swift | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/PagingKit/PagingMenuView.swift b/PagingKit/PagingMenuView.swift
index b29a033..00508dd 100644
--- a/PagingKit/PagingMenuView.swift
+++ b/PagingKit/PagingMenuView.swift
@@ -54,8 +54,13 @@ open class PagingMenuViewCell: UIView {
     public internal(set) var index: Int!
 }
 
+
+/// A set of methods that provides support for animations associated with a focus view transition.
+/// You can use a coordinator object to perform tasks that are related to a transition but that are separate from what the animator objects are doing.
 open class PagingMenuFocusViewAnimationCoordinator {
+    /// A frame at the start position
     public let beginFrame: CGRect
+    /// A frame at the end position
     public let endFrame: CGRect
     
     fileprivate var animationHandler: ((PagingMenuFocusViewAnimationCoordinator) -> Void)?
@@ -66,6 +71,11 @@ open class PagingMenuFocusViewAnimationCoordinator {
         self.endFrame = endFrame
     }
     
+    /// Runs the specified animations at the same time as the focus view animations.
+    ///
+    /// - Parameters:
+    ///   - animation: A block containing the animations you want to perform. These animations run in the same context as the focus view animations and therefore have the same default attributes.
+    ///   - completion: The block of code to execute after the animation finishes. You may specify nil for this
     open func animateFocusView(alongside animation: @escaping (PagingMenuFocusViewAnimationCoordinator) -> Void, completion: ((Bool) -> Void)?) {
         animationHandler = animation
         completionHandler = completion
@@ -84,7 +94,9 @@ open class PagingMenuFocusView: UIView {
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
     }
-    
+
+    /// A focus view makes this object when starting animation and destroy when finishing animation.
+    /// You can make a custom animation along a focus view animation.
     open var coordinator: PagingMenuFocusViewAnimationCoordinator?
 }
 

From 479bd78d755e941d3e0178a80a98eef924daae16 Mon Sep 17 00:00:00 2001
From: Kazuhiro Hayashi <kazuhiro.hayashi.49@gmail.com>
Date: Sat, 1 Dec 2018 11:40:21 +0900
Subject: [PATCH 13/13] fix interface

---
 PagingKit/PagingMenuView.swift                | 35 ++++++++++---------
 PagingKit/PagingMenuViewController.swift      | 15 +++++---
 .../iOS Sample/OverlayViewController.swift    |  5 +--
 3 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/PagingKit/PagingMenuView.swift b/PagingKit/PagingMenuView.swift
index 00508dd..fb0deb7 100644
--- a/PagingKit/PagingMenuView.swift
+++ b/PagingKit/PagingMenuView.swift
@@ -94,10 +94,6 @@ open class PagingMenuFocusView: UIView {
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
     }
-
-    /// A focus view makes this object when starting animation and destroy when finishing animation.
-    /// You can make a custom animation along a focus view animation.
-    open var coordinator: PagingMenuFocusViewAnimationCoordinator?
 }
 
 /**
@@ -142,12 +138,19 @@ public protocol PagingMenuViewDelegate: class {
     ///   - pagingMenuView: The paging menu view requesting this information.
     ///   - index: The index that specifies the location of the item.
     func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int)
-    func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView, at index: Int)
+    
+    /// Notifies the menu view that the frame of its focus view is about to change.
+    ///
+    /// - Parameters:
+    ///   - pagingMenuView: a menu view object informing the delegate.
+    ///   - index: end index
+    ///   - coordinator: animator coordinator
+    func pagingMenuView(pagingMenuView: PagingMenuView, willAnimateFocusViewTo index: Int, with coordinator: PagingMenuFocusViewAnimationCoordinator)
 }
 
 public extension PagingMenuViewDelegate {
     public func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int) {}
-    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView, at index: Int) {}
+    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimateFocusViewTo index: Int, with coordinator: PagingMenuFocusViewAnimationCoordinator) {}
 }
 
 /// Displays menu lists of information and supports selection and paging of the information.
@@ -410,18 +413,16 @@ open class PagingMenuView: UIScrollView {
         focusView.selectedIndex = index
         visibleCells.selectCell(with: index)
         
-        focusView.coordinator = PagingMenuFocusViewAnimationCoordinator(beginFrame: focusView.frame, endFrame: itemFrame)
-        menuDelegate?.pagingMenuView(pagingMenuView: self, willAnimate: focusView, at: index)
+        let coordinator = PagingMenuFocusViewAnimationCoordinator(beginFrame: focusView.frame, endFrame: itemFrame)
+        menuDelegate?.pagingMenuView(pagingMenuView: self, willAnimateFocusViewTo: index, with: coordinator)
         UIView.perform(.delete, on: [], options: UIView.AnimationOptions(rawValue: 0), animations: { [weak self] in
-            self?.contentOffset = offset
-            self?.focusView.frame = itemFrame
-            self?.focusView.layoutIfNeeded()
-            if let coordinator = self?.focusView.coordinator {
-                coordinator.animationHandler?(coordinator)
-            }
-        }, completion: { [weak self] (finished) in
-            self?.focusView.coordinator?.completionHandler?(finished)
-            self?.focusView.coordinator = nil
+            guard let _self = self else { return }
+            _self.contentOffset = offset
+            _self.focusView.frame = itemFrame
+            _self.focusView.layoutIfNeeded()
+            coordinator.animationHandler?(coordinator)
+        }, completion: { (finished) in
+            coordinator.completionHandler?(finished)
             completeHandler(finished)
         })
     }
diff --git a/PagingKit/PagingMenuViewController.swift b/PagingKit/PagingMenuViewController.swift
index 8e7ef7f..90e7be1 100644
--- a/PagingKit/PagingMenuViewController.swift
+++ b/PagingKit/PagingMenuViewController.swift
@@ -42,13 +42,20 @@ public protocol PagingMenuViewControllerDelegate: class {
     ///   - previousPage: An page number previously focusing menu in menu view controller.
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int)
     
-    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int)
+    
+    /// Notifies the menu view controller that the frame of its focus view is about to change.
+    ///
+    /// - Parameters:
+    ///   - viewController: A menu view controller object informing the delegate.
+    ///   - index: end index
+    ///   - coordinator: animator coordinator
+    func menuViewController(viewController: PagingMenuViewController, willAnimateFocusViewTo index: Int, with coordinator: PagingMenuFocusViewAnimationCoordinator)
 }
 
 extension PagingMenuViewControllerDelegate {
     public func menuViewController(viewController: PagingMenuViewController, focusViewDidEndTransition focusView: PagingMenuFocusView) {}
     
-    public func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int) {}
+    public func menuViewController(viewController: PagingMenuViewController, willAnimateFocusViewTo index: Int, with coordinator: PagingMenuFocusViewAnimationCoordinator) {}
 }
 
 /// The data source provides the paging menu view controller object with the information it needs to construct and modify the menus.
@@ -302,8 +309,8 @@ extension PagingMenuViewController: UIScrollViewDelegate {
 // MARK:- PagingMenuViewDelegate
 
 extension PagingMenuViewController: PagingMenuViewDelegate {
-    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimate focusView: PagingMenuFocusView, at index: Int) {
-        delegate?.menuViewController(viewController: self, willAnimate: focusView, at: index)
+    public func pagingMenuView(pagingMenuView: PagingMenuView, willAnimateFocusViewTo index: Int, with coordinator: PagingMenuFocusViewAnimationCoordinator) {
+        delegate?.menuViewController(viewController: self, willAnimateFocusViewTo: index, with: coordinator)
     }
     
     public func pagingMenuView(pagingMenuView: PagingMenuView, didSelectItemAt index: Int) {
diff --git a/iOS Sample/iOS Sample/OverlayViewController.swift b/iOS Sample/iOS Sample/OverlayViewController.swift
index 46d1254..bcbe395 100644
--- a/iOS Sample/iOS Sample/OverlayViewController.swift	
+++ b/iOS Sample/iOS Sample/OverlayViewController.swift	
@@ -103,12 +103,9 @@ extension OverlayViewController: PagingContentViewControllerDataSource {
 extension OverlayViewController: PagingMenuViewControllerDelegate {
     func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int) {
         contentViewController?.scroll(to: page, animated: true)
-        
     }
     
-    func menuViewController(viewController: PagingMenuViewController, willAnimate focusView: PagingMenuFocusView, at index: Int) {
-        guard let coordinator = focusView.coordinator else { return }
-        
+    func menuViewController(viewController: PagingMenuViewController, willAnimateFocusViewTo index: Int, with coordinator: PagingMenuFocusViewAnimationCoordinator) {
         viewController.visibleCells.compactMap { $0 as? OverlayMenuCell }.forEach { cell in
             cell.setFrame(viewController.menuView, maskFrame: coordinator.beginFrame, animated: true)
         }