[ADD] iOS 13 compatible AsyncImage implementation with cache

AltStore/Views/App Detail/AppScreenshotsScrollView.swift

@@ -0,0 +1,49 @@
+//
+//  AppScreenshotsScrollView.swift
+//  SideStore
+//
+//  Created by Fabian Thies on 27.11.22.
+//  Copyright © 2022 SideStore. All rights reserved.
+//
+
+import SwiftUI
+import AsyncImage
+
+
+/// Horizontal ScrollView with an asynchronously loaded image for each screenshot URL
+///
+/// The struct inherits the `Equatable` protocol and implements the respective comparisation function to prevent the view from being constantly re-rendered when a `@State` change in the parent view occurs.
+/// This way, the `AppScreenshotsScrollView` will only be reloaded when the parameters change.
+struct AppScreenshotsScrollView: View {
+    let urls: [URL]
+    var aspectRatio: CGFloat = 9/16
+    var height: CGFloat = 400
+    
+    var body: some View {
+        ScrollView(.horizontal, showsIndicators: false) {
+            HStack {
+                ForEach(urls) { url in
+                    AsyncImage(url: url) { image in
+                        image
+                            .resizable()
+                    } placeholder: {
+                        Rectangle()
+                            .foregroundColor(.secondary)
+                    }
+                    .aspectRatio(aspectRatio, contentMode: .fit)
+                    .cornerRadius(8)
+                }
+            }
+            .padding(.horizontal)
+        }
+        .frame(height: height)
+        .shadow(radius: 12)
+    }
+}
+
+extension AppScreenshotsScrollView: Equatable {
+    /// Prevent re-rendering of the view if the parameters didn't change
+    static func == (lhs: AppScreenshotsScrollView, rhs: AppScreenshotsScrollView) -> Bool {
+        lhs.urls == rhs.urls && lhs.aspectRatio == rhs.aspectRatio && lhs.height == rhs.height
+    }
+}