Supports viewing full screen app screenshots from AppViewController

[Missed] Uses layout config for PreviewAppScreenshots

AltStore/App Detail/AppViewController.swift

@@ -142,6 +142,14 @@ final class AppViewController: UIViewController
         self.view.layoutIfNeeded()
     }
     
+    override func viewIsAppearing(_ animated: Bool)
+    {
+        super.viewIsAppearing(animated)
+        
+        // Prevent banner temporarily flashing a color due to being added back to self.view.
+        self.bannerView.backgroundEffectView.backgroundColor = .clear
+    }
+    
     override func viewDidAppear(_ animated: Bool)
     {
         super.viewDidAppear(animated)
@@ -191,21 +199,7 @@ final class AppViewController: UIViewController
             self._shouldResetLayout = false
         }
                 
-        let statusBarHeight: Double
-        
-        if let navigationController, navigationController.presentingViewController != nil, navigationController.modalPresentationStyle != .fullScreen
-        {
-            statusBarHeight = 20
-        }
-        else if let statusBarManager = self.view.window?.windowScene?.statusBarManager
-        {
-            statusBarHeight = statusBarManager.statusBarFrame.height
-        }
-        else
-        {
-            statusBarHeight = 0
-        }
-        
+        let statusBarHeight = (self.view.window ?? self.presentedViewController?.view.window)?.windowScene?.statusBarManager?.statusBarFrame.height ?? 0
         let cornerRadius = self.contentViewControllerShadowView.layer.cornerRadius
         
         let inset = 12 as CGFloat

AltStore/App Detail/Screenshots/AppScreenshotsViewController.swift

@@ -129,6 +129,21 @@ private extension AppScreenshotsViewController
     }
 }
 
+extension AppScreenshotsViewController
+{
+    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
+    {
+        let screenshot = self.dataSource.item(at: indexPath)
+        
+        let previewViewController = PreviewAppScreenshotsViewController(app: self.app)
+        previewViewController.currentScreenshot = screenshot
+        
+        let navigationController = UINavigationController(rootViewController: previewViewController)
+        navigationController.modalPresentationStyle = .fullScreen
+        self.present(navigationController, animated: true)
+    }
+}
+
 @available(iOS 17, *)
 #Preview(traits: .portrait) {
     DatabaseManager.shared.startForPreview()

AltStore/App Detail/Screenshots/PreviewAppScreenshotsViewController.swift

@@ -0,0 +1,164 @@
+//
+//  PreviewAppScreenshotsViewController.swift
+//  AltStore
+//
+//  Created by Riley Testut on 9/19/23.
+//  Copyright © 2023 Riley Testut. All rights reserved.
+//
+
+import UIKit
+
+import AltStoreCore
+import Roxas
+
+import Nuke
+
+class PreviewAppScreenshotsViewController: UICollectionViewController
+{
+    let app: StoreApp
+    
+    var currentScreenshot: AppScreenshot?
+    
+    private lazy var dataSource = self.makeDataSource()
+    
+    init(app: StoreApp)
+    {
+        self.app = app
+        
+        super.init(collectionViewLayout: UICollectionViewFlowLayout())
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    override func viewDidLoad()
+    {
+        super.viewDidLoad()
+        
+        let tintColor = self.app.tintColor ?? .altPrimary
+        self.navigationController?.view.tintColor = tintColor
+        
+        self.view.backgroundColor = .systemBackground
+        self.collectionView.backgroundColor = nil
+        
+        let collectionViewLayout = self.makeLayout()
+        self.collectionView.collectionViewLayout = collectionViewLayout
+        
+        self.collectionView.directionalLayoutMargins.leading = 20
+        self.collectionView.directionalLayoutMargins.trailing = 20
+        
+        self.collectionView.preservesSuperviewLayoutMargins = true
+        self.collectionView.insetsLayoutMarginsFromSafeArea = true
+        
+        self.collectionView.alwaysBounceVertical = false
+        self.collectionView.register(AppScreenshotCollectionViewCell.self, forCellWithReuseIdentifier: RSTCellContentGenericCellIdentifier)
+        
+        self.collectionView.dataSource = self.dataSource
+        self.collectionView.prefetchDataSource = self.dataSource
+        
+        let doneButton = UIBarButtonItem(systemItem: .done, primaryAction: UIAction { [weak self] _ in
+            self?.dismiss(animated: true)
+        })
+        self.navigationItem.rightBarButtonItem = doneButton
+    }
+    
+    override func viewIsAppearing(_ animated: Bool)
+    {
+        super.viewIsAppearing(animated)
+        
+        if let screenshot = self.currentScreenshot, let index = self.dataSource.items.firstIndex(of: screenshot)
+        {
+            let indexPath = IndexPath(item: index, section: 0)
+            self.collectionView.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: false)
+        }
+    }
+}
+
+private extension PreviewAppScreenshotsViewController
+{
+    func makeLayout() -> UICollectionViewCompositionalLayout
+    {
+        let layoutConfig = UICollectionViewCompositionalLayoutConfiguration()
+        layoutConfig.contentInsetsReference = .none
+        
+        let layout = UICollectionViewCompositionalLayout(sectionProvider: { [weak self] (sectionIndex, layoutEnvironment) -> NSCollectionLayoutSection? in
+            guard let self else { return nil }
+            
+            let contentInsets = self.collectionView.directionalLayoutMargins
+            let groupWidth = layoutEnvironment.container.contentSize.width - (contentInsets.leading + contentInsets.trailing)
+            let groupHeight = layoutEnvironment.container.contentSize.height - (contentInsets.top + contentInsets.bottom)
+                        
+            let itemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .fractionalHeight(1.0))
+            let item = NSCollectionLayoutItem(layoutSize: itemSize)
+            
+            let groupSize = NSCollectionLayoutSize(widthDimension: .absolute(groupWidth), heightDimension: .absolute(groupHeight))
+            let group = NSCollectionLayoutGroup.horizontal(layoutSize: groupSize, subitems: [item])
+            
+            let layoutSection = NSCollectionLayoutSection(group: group)
+            layoutSection.orthogonalScrollingBehavior = .groupPagingCentered
+            layoutSection.interGroupSpacing = 10
+            return layoutSection
+        }, configuration: layoutConfig)
+        
+        return layout
+    }
+    
+    func makeDataSource() -> RSTArrayCollectionViewPrefetchingDataSource<AppScreenshot, UIImage>
+    {
+        let dataSource = RSTArrayCollectionViewPrefetchingDataSource<AppScreenshot, UIImage>(items: self.app.screenshots)
+        dataSource.cellConfigurationHandler = { (cell, screenshot, indexPath) in
+            let cell = cell as! AppScreenshotCollectionViewCell
+            cell.imageView.image = nil
+            cell.imageView.isIndicatingActivity = true
+            
+            var aspectRatio = screenshot.size ?? AppScreenshot.defaultAspectRatio
+            if aspectRatio.width > aspectRatio.height
+            {
+                aspectRatio = CGSize(width: aspectRatio.height, height: aspectRatio.width)
+            }
+            
+            cell.aspectRatio = aspectRatio
+        }
+        dataSource.prefetchHandler = { (screenshot, indexPath, completionHandler) in
+            let imageURL = screenshot.imageURL
+            return RSTAsyncBlockOperation() { (operation) in
+                let request = ImageRequest(url: imageURL, processors: [.screenshot])
+                ImagePipeline.shared.loadImage(with: request, progress: nil) { result in
+                    guard !operation.isCancelled else { return operation.finish() }
+                    
+                    switch result
+                    {
+                    case .success(let response): completionHandler(response.image, nil)
+                    case .failure(let error): completionHandler(nil, error)
+                    }
+                }
+            }
+        }
+        dataSource.prefetchCompletionHandler = { (cell, image, indexPath, error) in
+            let cell = cell as! AppScreenshotCollectionViewCell
+            cell.imageView.isIndicatingActivity = false
+            cell.imageView.image = image
+            
+            if let error = error
+            {
+                print("Error loading image:", error)
+            }
+        }
+        
+        return dataSource
+    }
+}
+
+@available(iOS 17, *)
+#Preview(traits: .portrait) {
+    DatabaseManager.shared.startForPreview()
+    
+    let fetchRequest = StoreApp.fetchRequest()
+    let storeApp = try! DatabaseManager.shared.viewContext.fetch(fetchRequest).first!
+    
+    let previewViewController = PreviewAppScreenshotsViewController(app: storeApp)
+    
+    let navigationController = UINavigationController(rootViewController: previewViewController)
+    return navigationController
+}