[Feat] #192 - 줌 기능 구현

Author: OneTen19

Neki-iOS/Features/Archive/Sources/Presentation/Sources/Components/ZoomableImageView.swift

@@ -0,0 +1,118 @@
+//
+//  ZoomableImageView.swift
+//  Neki-iOS
+//
+//  Created by OneTen on 3/28/26.
+//
+
+import SwiftUI
+import Kingfisher
+
+struct ZoomableImageView: View {
+    let imageURL: URL?
+    let isCurrent: Bool
+    
+    @State private var scale: CGFloat = 1.0
+    @State private var lastScale: CGFloat = 1.0
+    @State private var offset: CGSize = .zero
+    @State private var lastOffset: CGSize = .zero
+    
+    var body: some View {
+        GeometryReader { geo in
+            KFImage(imageURL)
+                .resizable()
+                .placeholder {
+                    ProgressView()
+                        .frame(maxWidth: .infinity, maxHeight: .infinity)
+                }
+                .retry(maxCount: 3, interval: .seconds(5))
+                .cancelOnDisappear(true)
+                .aspectRatio(contentMode: .fit)
+                .frame(maxWidth: .infinity, maxHeight: .infinity)
+                .scaleEffect(scale)
+                .offset(offset)
+                .gesture(
+                    MagnifyGesture()
+                        .onChanged { value in
+                            let delta = value.magnification / lastScale
+                            lastScale = value.magnification
+                            scale = min(max(scale * delta, 0.8), 5.0) // 0.8 ~ 5배까지
+                        }
+                        .onEnded { _ in
+                            lastScale = 1.0
+                            if scale <= 1.0 {
+                                clampOffset(geo: geo)
+                            }
+                        }
+                )
+            
+            // 확대된 상태에서 이미지 이동
+                .highPriorityGesture(
+                    DragGesture()
+                        .onChanged { value in
+                            // 드래그 가능한 최대 범위 계산
+                            let maxX = max(0, (geo.size.width * (scale - 1)) / 2)
+                            let maxY = max(0, (geo.size.height * (scale - 1)) / 2)
+                            
+                            let proposedWidth = lastOffset.width + value.translation.width
+                            let proposedHeight = lastOffset.height + value.translation.height
+                            
+                            // 계산된 범위 내에서만 offset 적용
+                            offset = CGSize(
+                                width: min(max(proposedWidth, -maxX), maxX),
+                                height: min(max(proposedHeight, -maxY), maxY)
+                            )
+                        }
+                        .onEnded { _ in
+                            lastOffset = offset
+                        },
+                    including: scale > 1.0 ? .gesture : .subviews
+                )
+            
+            // 더블 탭 줌
+                .onTapGesture(count: 2) {
+                    if scale > 1.0 {
+                        resetZoom()
+                    } else {
+                        withAnimation(.spring()) {
+                            scale = 2.5
+                        }
+                    }
+                }
+            
+            // 스와이프로 다음 사진으로 넘어갔을 때 이전 사진 줌 초기화
+                .onChange(of: isCurrent) { _, newValue in
+                    if !newValue {
+                        resetZoom(animated: false)
+                    }
+                }
+        }
+    }
+    
+    private func resetZoom(animated: Bool = true) {
+        if animated {
+            withAnimation(.spring(response: 0.3, dampingFraction: 0.8)) {
+                scale = 1.0
+                offset = .zero
+            }
+        } else {
+            scale = 1.0
+            offset = .zero
+        }
+        lastScale = 1.0
+        lastOffset = .zero
+    }
+    
+    private func clampOffset(geo: GeometryProxy) {
+        let maxX = max(0, (geo.size.width * (scale - 1)) / 2)
+        let maxY = max(0, (geo.size.height * (scale - 1)) / 2)
+        
+        let newX = min(max(offset.width, -maxX), maxX)
+        let newY = min(max(offset.height, -maxY), maxY)
+        
+        withAnimation(.spring(response: 0.3, dampingFraction: 0.8)) {
+            offset = CGSize(width: newX, height: newY)
+            lastOffset = offset
+        }
+    }
+}

Neki-iOS/Features/Archive/Sources/Presentation/Sources/View/ArchivePhotoDetailView.swift

@@ -100,21 +100,15 @@ extension ArchivePhotoDetailView {
         )
     }
 
-    // 사진 영역
     private var photoTabView: some View {
         TabView(selection: $store.currentItemID) {
             ForEach(store.photos) { item in
-                KFImage(item.imageURL)
-                    .resizable()
-                    .placeholder {
-                        ProgressView()
-                            .frame(maxWidth: .infinity, maxHeight: .infinity)
-                    }
-                    .retry(maxCount: 3, interval: .seconds(5))
-                    .cancelOnDisappear(true)
-                    .aspectRatio(contentMode: .fit)
-                    .frame(maxWidth: .infinity, maxHeight: .infinity)
-                    .tag(item.id)
+                ZoomableImageView(
+                    imageURL: item.imageURL,
+                    isCurrent: store.currentItemID == item.id
+                )
+                .frame(maxWidth: .infinity, maxHeight: .infinity)
+                .tag(item.id)
             }
         }
         .tabViewStyle(.page(indexDisplayMode: .never))