chore 히어로 애니메이션 주석 추가

Author: hyunjuntyler

Projects/Features/MainFeature/Sources/Utilities/CollectionViewCellTransitioning.swift

@@ -48,10 +48,14 @@ extension CollectionViewCellTransitioning: UIViewControllerAnimatedTransitioning
         transitionDuration
     }
 
+    /// 실제 Transition 구현 부분
     func animateTransition(using transitionContext: any UIViewControllerContextTransitioning) {
+        /// 전환에 관련된 뷰를 사용합니다.
         let containerView = transitionContext.containerView
+        /// 1. 깔끔한 애니메이션을 위해 transition되는 containerView의 모든 요소를 제거합니다.
         containerView.subviews.forEach { $0.removeFromSuperview() }
 
+        /// 2. 전환에 사용되는 뷰에 blurEffectView 추가합니다.
         blurEffectView.frame = containerView.frame
         blurEffectView.alpha = transition.next.blurAlpha
         containerView.addSubview(blurEffectView)
@@ -60,45 +64,61 @@ extension CollectionViewCellTransitioning: UIViewControllerAnimatedTransitioning
         let toView = transitionContext.viewController(forKey: .to)
 
         var thumbnailView: ThumbnailView?
+        /// 3. Present: 시작하는 뷰의 썸네일을 가져옵니다. (시작 좌표 및 복사를 위해)
         if let navigationController = (fromView as? UINavigationController), let viewController = (navigationController.topViewController as? BroadcastCollectionViewController) {
             thumbnailView = viewController.selectedThumbnailView
         }
 
+        /// 3. Dismiss: 목적지 뷰의 썸네일을 가져옵니다. (도착 좌표 및 복사를 위해)
         if let navigationController = (toView as? UINavigationController), let viewController = (navigationController.topViewController as? BroadcastCollectionViewController) {
             thumbnailView = viewController.selectedThumbnailView
         }
 
+        /// 4. 썸네일 뷰를 복사하고 절대 프레임을 가져옵니다.
         guard let thumbnailView else { return }
         let thumbnailViewCopy = copy(of: thumbnailView)
-        containerView.addSubview(thumbnailViewCopy)
-        thumbnailView.isHidden = true
-        
         let absoluteFrame = thumbnailView.convert(thumbnailView.frame, to: nil)
-        thumbnailViewCopy.frame = absoluteFrame
-        thumbnailViewCopy.layoutIfNeeded()
 
-        backgroundView.frame = transition == .present ? thumbnailViewCopy.imageView.frame : containerView.frame
+        /// 애니메이션의 디테일을 위한 설정
+        backgroundView.frame = transition == .present ? absoluteFrame : containerView.frame
         backgroundView.layer.cornerRadius = transition.cornerRadius
         thumbnailViewCopy.insertSubview(backgroundView, aboveSubview: thumbnailViewCopy.shadowView)
 
+        /// 5. 기존 썸네일을 숨기고 복사한 썸네일을 containerView에 추가합니다.
+        containerView.addSubview(thumbnailViewCopy)
+        thumbnailView.isHidden = true
+        
+        /// 6. Present: 애니메이션, 작았다 커지면서 위로 이동합니다.
         if transition == .present, let toView {
+            /// 6-1. 썸네일은 원래 위치에서 시작
+            thumbnailViewCopy.frame = absoluteFrame
+            /// 6-2. containerView에 띄워줄 뷰 추가 후 숨김
             containerView.addSubview(toView.view)
             toView.view.isHidden = true
+            /// 6-3. 애니메이션
             moveAndConvert(thumbnailView: thumbnailViewCopy, containerView: containerView, to: absoluteFrame) {
+                /// 6-4. 띄워줄 뷰 표시
                 toView.view.isHidden = false
+                /// 6-5. 썸네일 복사 뷰 제거, 썸네일 뷰 원상복구 (표시)
                 thumbnailViewCopy.removeFromSuperview()
                 thumbnailView.isHidden = false
+                /// 6-6. 애니메이션 종료 알림
                 transitionContext.completeTransition(true)
             }
         }
 
+        /// 6. Dismiss: 위에서 셀의 위치로 돌아오면서 작아집니다.
         if transition == .dismiss, let fromView {
+            /// 6-1. 시작 뷰 숨김
             fromView.view.isHidden = true
-
+            /// 6-2. 썸네일 복사 뷰 위치를 시작하는 플레이어 위치부터 시작
             thumbnailViewCopy.frame = CGRect(x: 0, y: fromView.view.layoutMargins.top, width: containerView.frame.width, height: containerView.frame.width * 0.5625)
-            
+            /// 6-3. 애니메이션
             moveAndConvert(thumbnailView: thumbnailViewCopy, containerView: containerView, to: absoluteFrame) {
+                /// 6-4. 썸네일 복사 뷰 제거, 썸네일 뷰 원상복구 (표시)
+                thumbnailViewCopy.removeFromSuperview()
                 thumbnailView.isHidden = false
+                /// 6-6. 애니메이션 종료 알림
                 transitionContext.completeTransition(true)
             }
         }
@@ -113,26 +133,36 @@ extension CollectionViewCellTransitioning {
         return thumbnailViewCopy
     }
 
+    /// Present 때 사용되는 애니메이션
+    /// 썸네일을 잠깐 축소했다가 확대시키면서 애니메이션이 진행됩니다.
     private func makeShrinkAnimator(of thumbnailView: ThumbnailView) -> UIViewPropertyAnimator {
         UIViewPropertyAnimator(duration: shrinkDuration, curve: .linear) {
             thumbnailView.transform = CGAffineTransform(scaleX: 0.95, y: 0.95)
         }
     }
 
+    /// Present, Dismiss 때 사용되는 애니메이션
     private func makeExpandContractAnimator(of thumbnailView: ThumbnailView, in containerView: UIView, to frame: CGRect) -> UIViewPropertyAnimator {
+        /// 애니메이션 설정
         let springTiming = UISpringTimingParameters(dampingRatio: 0.75, initialVelocity: CGVector(dx: 0, dy: 2))
         let animator = UIViewPropertyAnimator(duration: transitionDuration - shrinkDuration, timingParameters: springTiming)
 
         animator.addAnimations {
-            thumbnailView.transform = .identity
-            
-            if self.transition == .present {
+            switch self.transition {
+            case .present:
+                /// 작아졌던 썸네일 뷰 원상태로
+                thumbnailView.transform = .identity
+                /// 썸네일 뷰 Style, Layout 업데이트
                 thumbnailView.updateStyles(for: .present)
                 thumbnailView.updateLayouts(for: .present)
+                /// 썸네일 뷰 플레이어뷰 위치로 이동 및 확대
                 thumbnailView.frame = CGRect(x: 0, y: containerView.layoutMargins.top, width: containerView.frame.width, height: containerView.frame.width * 0.5625)
-            } else {
+                
+            case .dismiss:
+                /// 썸네일 뷰 Style, Layout 업데이트
                 thumbnailView.updateStyles(for: .dismiss)
                 thumbnailView.updateLayouts(for: .dismiss)
+                /// 인자로 받은 frame위치로 이동 (기존 썸네일 뷰의 절대 프레임)
                 thumbnailView.frame = frame
             }
 
@@ -153,20 +183,21 @@ extension CollectionViewCellTransitioning {
         let shrinkAnimator = makeShrinkAnimator(of: thumbnailView)
         let expandContractAnimator = makeExpandContractAnimator(of: thumbnailView, in: containerView, to: frame)
 
-        expandContractAnimator.addCompletion { _ in
-            completion()
-        }
-        
-        if transition == .present {
+        switch transition {
+        case .present:
+            shrinkAnimator.startAnimation()
+            
             shrinkAnimator.addCompletion { _ in
-                thumbnailView.layoutIfNeeded()
                 expandContractAnimator.startAnimation()
             }
 
-            shrinkAnimator.startAnimation()
-        } else {
+        case .dismiss:
             thumbnailView.layoutIfNeeded()
             expandContractAnimator.startAnimation()
         }
+        
+        expandContractAnimator.addCompletion { _ in
+            completion()
+        }
     }
 }

Projects/Features/MainFeature/Sources/ViewControllers/BroadcastCollectionViewController.swift

@@ -132,6 +132,8 @@ extension BroadcastCollectionViewController: UICollectionViewDelegate {
     public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
         guard let channel = dataSource?.itemIdentifier(for: indexPath) else { return }
         guard let viewController = factory?.make(channelID: channel.id, title: channel.name, owner: channel.owner, description: channel.description) else { return }
+
+        /// 히어로 애니메이션 전환 적용
         viewController.modalPresentationStyle = .overFullScreen
         viewController.transitioningDelegate = transitioning
         present(viewController, animated: true)