feat: load images from cbz files instead

ImageViewer/ViewController.swift

@@ -1,6 +1,7 @@
 // TODO: Anilist support?
 // TODO: Properly avoid swallowing of input from UICollectionView used for scrolling
 // TODO: Convert between state for normal and scrolling page turn
+// TODO: Support reading with scrolling and landscape mode
 
 import FlatBuffers
 import Foundation
@@ -193,10 +194,9 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                 metadataList[dir] = metadata
                 loadLocalState()
                 let volCovP = ProgressIndices(v: progress.v, c: 0, i: 0)
-                let archivePath = getArchiveURL(volCovP.v)
-                let archive = try! Archive(url: archivePath, accessMode: .read)
-                let filename = metadata.volumes[volCovP.v].chapters[volCovP.c].images[volCovP.i].filename!
-                let targetEntry = archive[filename]!
+                let volumeDir = currentPath.appendingPathComponent("volumes")
+                let archive = try! Archive(url: volumeDir.appendingPathComponent(metadata.volumes[progress.v].archive), accessMode: .read)
+                let targetEntry = archive[metadata.volumes[volCovP.v].chapters[volCovP.c].images[volCovP.i].filename]!
                 var extractedData = Data()
                 _ = try archive.extract(targetEntry) { data in
                     extractedData.append(data)
@@ -206,8 +206,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                         cover: UIImage(data: extractedData)!,
                         metadata: metadata,
                         path: dir
-                    )
-                )
+                ))
             }
         } catch {
             print("Failed to read directories")
@@ -266,7 +265,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     func getMetadataFromFilename(path: URL) {
         // Beautiful, is it not?
         let patterns: [(NSRegularExpression, NSRegularExpression, Int, Int, Int)] = [
-            (try! NSRegularExpression(pattern: #"c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-p?[0-9]+)?)"#), try! NSRegularExpression(pattern: #"^(.*) - c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-p?[0-9]+)?)"#), 3, 1, 2),
+            (try! NSRegularExpression(pattern: #"c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-[0-9]+)?)"#), try! NSRegularExpression(pattern: #"^(.*) - c([0-9]+(?:x[0-9]+)?) \(v([0-9]+)\) - p([0-9]+(?:-[0-9]+)?)"#), 3, 1, 2),
             (try! NSRegularExpression(pattern: "v([0-9]+) p([0-9]+(?:-[0-9]+)?) - c([0-9]+(?:x[0-9]+)?)"), try! NSRegularExpression(pattern: "^(.*) - v([0-9]+) p([0-9]+(?:-[0-9]+)?) - c([0-9]+(?:x[0-9]+)?)"), 2, 3, 1),
         ]
         var pattern: NSRegularExpression! = nil
@@ -291,7 +290,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         var volumes: [Offset] = []
         var currentChapters: [Offset] = []
         var currentImages: [Offset] = []
-        var previousVolumeURL = ""
 
         var titleValue: String = ""
 
@@ -307,7 +305,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             includingPropertiesForKeys: [.isRegularFileKey],
             options: [.skipsHiddenFiles]
         ).filter { $0.pathExtension == "cbz" }
-         .sorted { $0.lastPathComponent < $1.lastPathComponent }
 
         if volumeURLs.isEmpty {
             print("found no volumes in volume dir: \(volumeDir)")
@@ -330,6 +327,8 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             return
         }
 
+        print("example filename in archive: \(filenames[0].1), \(filenames[1].1)")
+
         do {
             for (currentPattern, currentTitlePattern, currentPageRegexPosition, currentChapterRegexPosition, currentVolumeRegexPosition) in patterns {
                 let filename = filenames[0].1
@@ -376,6 +375,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                 return
             }
 
+
             let regex = pattern!
             let titleRegex = titlePattern!
 
@@ -403,7 +403,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                     let (page, doublePage) = (
                         UInt32(pageParts[0])!, pageParts.count > 1
                     )
-
+                    
                     let archive = try Archive(url: volumeDir.appendingPathComponent(volumeURL), accessMode: .read)
                     let entry = archive[filename]!
                     var size = ImageDimensions(width: 0, height: 0)
@@ -414,10 +414,10 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                         return
                     }
                     let m_filename = builder.create(string: filename)
-                    let imageMetadata = ImageMetadata.createImageMetadata(&builder,
-                        doublePage: doublePage,
-                        filenameOffset: m_filename,
-                        firstPage: page,
+                    let imageMetadata = ImageMetadata.createImageMetadata(&builder, 
+                        doublePage: doublePage, 
+                        filenameOffset: m_filename, 
+                        firstPage: page, 
                         size: Size(width: UInt32(size.width), height: UInt32(size.height))
                     )
 
@@ -427,7 +427,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
 
                             let chapterName = builder.create(string: "")
                             let imagesOffset = builder.createVector(ofOffsets: currentImages)
-                            let chapterMetadata = ChapterMetadata.createChapterMetadata(&builder,
+                            let chapterMetadata = ChapterMetadata.createChapterMetadata(&builder, 
                                 chapter: MetaValue(
                                     main: currentChapter.0, bonus: currentChapter.1 ?? 0
                                 ),
@@ -438,12 +438,12 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                             currentChapters.append(chapterMetadata)
 
                             let volumeTitle = builder.create(string: "")
-                            let volumeURLOffset = builder.create(string: previousVolumeURL)
+                            let volumeURLOffset = builder.create(string: volumeURL)
                             let chaptersOffset = builder.createVector(ofOffsets: currentChapters)
                             let volumeMetadata = VolumeMetadata.createVolumeMetadata(
                                 &builder,
-                                volume: MetaValue(main: currentVolume, bonus: 0),
-                                titleOffset: volumeTitle,
+                                volume: MetaValue(main: currentVolume, bonus: 0), 
+                                titleOffset: volumeTitle, 
                                 archiveOffset: volumeURLOffset,
                                 chaptersVectorOffset: chaptersOffset,
                             )
@@ -461,7 +461,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
 
                             let chapterName = builder.create(string: "")
                             let imagesOffset = builder.createVector(ofOffsets: currentImages)
-                            let chapterMetadata = ChapterMetadata.createChapterMetadata(&builder,
+                            let chapterMetadata = ChapterMetadata.createChapterMetadata(&builder, 
                                 chapter: MetaValue(
                                     main: currentChapter.0, bonus: currentChapter.1 ?? 0
                                 ),
@@ -482,7 +482,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                     if (i == filenames.count - 1) {
                         let chapterName = builder.create(string: "")
                         let imagesOffset = builder.createVector(ofOffsets: currentImages)
-                        let chapterMetadata = ChapterMetadata.createChapterMetadata(&builder,
+                        let chapterMetadata = ChapterMetadata.createChapterMetadata(&builder, 
                             chapter: MetaValue(
                                 main: chapter.0, bonus: chapter.1 ?? 0
                             ),
@@ -497,8 +497,8 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                         let chaptersOffset = builder.createVector(ofOffsets: currentChapters)
                         let volumeMetadata = VolumeMetadata.createVolumeMetadata(
                             &builder,
-                            volume: MetaValue(main: volume, bonus: 0),
-                            titleOffset: volumeTitle,
+                            volume: MetaValue(main: volume, bonus: 0), 
+                            titleOffset: volumeTitle, 
                             archiveOffset: volumeURLOffset,
                             chaptersVectorOffset: chaptersOffset
                         )
@@ -510,7 +510,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                     }
                     currentVolume = volume
                     currentChapter = chapter
-                    previousVolumeURL = volumeURL
                 } else {
                     print("no regex match on \(filename), returning")
                     return
@@ -692,35 +691,73 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             var offset = scrollingCollectionView.contentOffset
             offset.y *= (screenSize.width / screenSize.height)
             scrollingCollectionView.setContentOffset(offset, animated: false)
+            // FIXME: This is a caching issue, needs a different cache for scrolling since it Fill instead of Fit.
+            scrollingCollectionView.reloadData()
         }
     }
 
     func readComic(name: String) {
-        imageView.image = nil
         readerView.isHidden = false
         homeView.isHidden = true
         setNeedsStatusBarAppearanceUpdate()
         if let path = getPathFromComicName(name: name) {
             currentPath = path
+
             metadata = metadataList[path]
 
             globalState.comicName = metadata.title
             saveGlobalState()
             loadLocalState()
-            scrollingCollectionView.isHidden = mode != .scroll
-            leftView.isHidden = mode == .scroll
-            rightView.isHidden = mode == .scroll
-            imageView.isHidden = mode == .scroll
-            if mode == .scroll {
-                scrollingCollectionView.reloadData()
+            if mode != .scroll {
+                scrollingCollectionView.isHidden = true
+                leftView.isHidden = false
+                rightView.isHidden = false
+                setImages(path: path)
             } else {
-                setImages()
+                setupScrolling()
             }
         } else {
             print("path not found")
         }
     }
 
+    func setupScrolling() {
+        leftView.isHidden = true
+        rightView.isHidden = true
+        scrollingCollectionView.isHidden = false
+        scrollingCollectionView.reloadData()
+    }
+
+    func countFiles() -> Int {
+        var count = 0
+        if let enumerator = fileManager.enumerator(
+            at: currentPath, includingPropertiesForKeys: [.isDirectoryKey],
+            options: [.skipsHiddenFiles]
+        ) {
+            for case let dir as URL in enumerator {
+                do {
+                    if let enumerator = fileManager.enumerator(
+                        at: dir, includingPropertiesForKeys: [.isRegularFileKey],
+                        options: [.skipsHiddenFiles]
+                    ) {
+                        for case let file as URL in enumerator {
+                            let resourceValues = try file.resourceValues(forKeys: [
+                                .isRegularFileKey,
+                            ])
+                            if resourceValues.isRegularFile == true {
+                                count += 1
+                            }
+                        }
+                    }
+
+                } catch {
+                    print("Error reading file attributes for \(dir):", error)
+                }
+            }
+        }
+        return count
+    }
+
     func setupScrollingCollectionView() {
         let layout = UICollectionViewFlowLayout()
         layout.minimumInteritemSpacing = 0
@@ -1007,11 +1044,13 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             default: break
             }
             if prev == mode { return }
-            if mode != .scroll {
-                let archiveURL = getArchiveURL(progress.v)
+            if mode == .scroll {
+                setupScrolling()
+            } else {
+                let archiveURL = currentPath.appendingPathComponent("volumes").appendingPathComponent(metadata.volumes[progress.v].archive)
                 imageLoader.loadImage(
                     archiveURL: archiveURL,
-                    filename: getImagePath(progress),
+                    filename: getImagePath(progress: progress),
                     scaling: .scaleAspectFit,
                     screenSize: UIScreen.main.bounds.size
                 ) { [weak self] image in
@@ -1023,10 +1062,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         leftView.isHidden = mode == .scroll
         rightView.isHidden = mode == .scroll
         imageView.isHidden = mode == .scroll
-        // This does not optmize for the case where you switch between scrolling and non-scrolling in the same comic. However this badly supported because of the lac of state conversion.
-        if mode == .scroll {
-            scrollingCollectionView.reloadData()
-        }
         togglePageTurnDropdown()
         saveLocalState()
     }
@@ -1155,27 +1190,21 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         }
         progress = newProgress
         updateInfo()
-        let path = getImagePath(progress)
+        let path = getImagePath(progress: progress)
 
         imageLoader.setActiveWindow([path])
 
-        imageLoader.loadImage(
-            archiveURL: getArchiveURL(progress.v),
-            filename: getImagePath(progress),
-            scaling: scaling,
-            screenSize: UIScreen.main.bounds.size
-        ) { [weak self] image in
+        let archiveURL = currentPath.appendingPathComponent("volumes").appendingPathComponent(metadata.volumes[progress.v].archive)
+        imageLoader.loadImage(archiveURL: archiveURL, filename: getImagePath(progress: progress), scaling: scaling, screenSize: UIScreen.main.bounds.size) { [weak self] image in
             self?.imageView.image = image
         }
 
         for _ in 0 ..< preloadCount {
             newProgress = getProgressIndicesFromTurn(turn: .next, progress: newProgress)
-            imageLoader.preloadImage(
-                archiveURL: getArchiveURL(newProgress.v),
-                filename: getImagePath(newProgress),
-                scaling: scaling,
-                screenSize: UIScreen.main.bounds.size
-            )
+            let archive = metadata.volumes[newProgress.v].archive!
+            let filename = getImagePath(progress: newProgress)
+            let archiveURL = currentPath.appendingPathComponent("volumes").appendingPathComponent(archive)
+            imageLoader.preloadImage(archiveURL: archiveURL, filename: filename, scaling: scaling, screenSize: UIScreen.main.bounds.size)
         }
 
         saveLocalState()
@@ -1244,11 +1273,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         info.text = text
     }
 
-    func getArchiveURL(_ volumeProgress: Int) -> URL {
-        return currentPath.appendingPathComponent("volumes").appendingPathComponent(metadata.volumes[volumeProgress].archive)
-    }
-
-    func getImagePath(_ progress: ProgressIndices) -> String {
+    func getImagePath(progress: ProgressIndices) -> String {
         let (v, c, i) = (progress.v, progress.c, progress.i)
         let modernPath = metadata.volumes[v].chapters[c].images[i].filename!
         // if fileManager.fileExists(atPath: modernPath.path) {
@@ -1298,27 +1323,25 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         return metadata
     }
 
-    func setImages() {
-        let scaling: UIView.ContentMode = mode == .scroll ? .scaleAspectFill : .scaleAspectFit
+    func setImages(path _: URL) {
+        let scaling: UIView.ContentMode!
+        if mode == .scroll {
+            scaling = UIView.ContentMode.scaleAspectFill
+        } else { scaling = UIView.ContentMode.scaleAspectFit }
         imageLoader.loadImage(
-            archiveURL: getArchiveURL(progress.v),
-            filename: getImagePath(progress),
+            archiveURL: currentPath.appendingPathComponent("volumes").appendingPathComponent(metadata.volumes[progress.v].archive),
+            filename: getImagePath(progress: progress),
             scaling: scaling,
             screenSize: UIScreen.main.bounds.size
         ) { [weak self] image in
             self?.imageView.image = image
+            self?.updateInfo()
         }
-        updateInfo()
 
         var newProgress = progress
         for _ in 0 ..< preloadCount {
             newProgress = getProgressIndicesFromTurn(turn: .next, progress: newProgress)
-            imageLoader.preloadImage(
-                archiveURL: getArchiveURL(newProgress.v),
-                filename: getImagePath(newProgress),
-                scaling: scaling,
-                screenSize: UIScreen.main.bounds.size,
-            )
+            imageLoader.preloadImage(archiveURL: currentPath.appendingPathComponent("volumes").appendingPathComponent(metadata.volumes[progress.v].archive), filename: getImagePath(progress: newProgress), scaling: scaling, screenSize: UIScreen.main.bounds.size)
         }
     }
 
@@ -1337,14 +1360,15 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         super.viewWillTransition(to: size, with: coordinator)
         if mode != .scroll {
             imageLoader.loadImage(
-                archiveURL: getArchiveURL(progress.v),
-                filename: getImagePath(progress),
+                archiveURL: currentPath.appendingPathComponent("volumes").appendingPathComponent(metadata.volumes[progress.v].archive),
+                filename: getImagePath(progress: progress),
                 scaling: .scaleAspectFit,
                 screenSize: size
             ) { image in
                 self.imageView.image = image
             }
         } else {
+            scrollingCollectionView.reloadData()
             changedOrientation = true
         }
     }
@@ -1421,7 +1445,6 @@ extension ViewController: UICollectionViewDataSource, UICollectionViewDelegateFl
                     withReuseIdentifier: "ScrollingImageCell", for: indexPath
                 )
                 as! ScrollingImageCell
-            if mode != .scroll { return cell }
             if metadata == nil {
                 print("metadata is nil, should probably not be the case")
                 return cell
@@ -1433,10 +1456,9 @@ extension ViewController: UICollectionViewDataSource, UICollectionViewDelegateFl
             }
             }
             imageLoader.loadImage(
-              archiveURL: getArchiveURL(progress.v),
-              filename: getImagePath(newProgress),
-              scaling: scaling, screenSize: UIScreen.main.bounds.size
-            ) { image in
+              archiveURL: currentPath.appendingPathComponent("volumes").appendingPathComponent(metadata.volumes[progress.v].archive),
+              filename: getImagePath(progress: newProgress), 
+              scaling: scaling, screenSize: UIScreen.main.bounds.size) { image in
                 cell.imageView.image = image
             }
             return cell
@@ -1550,21 +1572,15 @@ enum Rotation {
 
 class ImageLoader {
     private let cache = NSCache<NSString, UIImage>()
-    private let portraitFitCache = NSCache<NSString, UIImage>()
-    private let landscapeFitCache = NSCache<NSString, UIImage>()
-    private let portraitFillCache = NSCache<NSString, UIImage>()
-    private let landscapeFillCache = NSCache<NSString, UIImage>()
+    private let horCache = NSCache<NSString, UIImage>()
     private var loadingTasks: [String: (UIImage?) -> Void] = [:]
     private var activeTokens: [String: CancellationToken] = [:]
-    private let archives = NSCache<NSString, Archive>()
+    private var archives = NSCache<NSString, Archive>()
 
     init() {
         // 128 MiB
         cache.totalCostLimit = 128 * 1024 * 1024
-        portraitFitCache.totalCostLimit = 128 * 1024 * 1024
-        landscapeFitCache.totalCostLimit = 128 * 1024 * 1024
-        portraitFillCache.totalCostLimit = 128 * 1024 * 1024
-        landscapeFillCache.totalCostLimit = 128 * 1024 * 1024
+        horCache.totalCostLimit = 128 * 1024 * 1024
         // The reason archives are cached and have a strict limit of four, is because Archive supposedly opens a posix file pointer and keeps it until the object is destroyed.
         archives.countLimit = 4
     }
@@ -1573,6 +1589,7 @@ class ImageLoader {
         loadImage(archiveURL: archiveURL, filename: filename, scaling: scaling, screenSize: screenSize, completion: nil)
     }
 
+    // FIXME: So scrolling is not really handled well in terms of caching. This is because it should have a separate cache since it uses a different scaling (Fill instead of Fit).
     func loadImage(
         archiveURL: URL, filename: String,
         scaling: UIView.ContentMode,
@@ -1582,28 +1599,23 @@ class ImageLoader {
         let rotation: Rotation = screenSize.width > screenSize.height ? .horizontal : .vertical
         let key = filename
 
-        if scaling == .scaleAspectFit {
-            if rotation == .vertical, let cached = portraitFitCache.object(forKey: key as NSString) {
-                completion?(cached); return
+        if rotation == .vertical, let cached = cache.object(forKey: key as NSString) {
+            completion?(cached); return
+        }
+        if rotation == .horizontal, let cached = horCache.object(forKey: key as NSString) {
+            completion?(cached); return
+        }
+
+        if let existing = activeTokens[key], !existing.isCancelled {
+            if let completion = completion {
+                loadingTasks[key] = completion
             }
-            if rotation == .horizontal, let cached = landscapeFitCache.object(forKey: key as NSString) {
-                completion?(cached); return
-            }
-        } else if scaling == .scaleAspectFill {
-            if rotation == .vertical, let cached = portraitFillCache.object(forKey: key as NSString) {
-                completion?(cached); return
-            }
-            if rotation == .horizontal, let cached = landscapeFillCache.object(forKey: key as NSString) {
-                completion?(cached); return
-            }
-        } else { assertionFailure() }
+            return
+        }
 
         if let completion = completion {
             loadingTasks[key] = completion
         }
-        if let existing = activeTokens[key], !existing.isCancelled {
-            return
-        }
 
         let token = CancellationToken()
         activeTokens[key] = token
@@ -1611,102 +1623,72 @@ class ImageLoader {
         queue.async { [weak self] in
             guard let self = self else { return }
 
-            func finish() {
+            func finish(_ image: UIImage?) {
                 DispatchQueue.main.async {
                     guard self.activeTokens[key] === token else { return }
                     self.activeTokens.removeValue(forKey: key)
-                    self.loadingTasks.removeValue(forKey: key)
-                }
-            }
-            func setImage(_ image: UIImage) {
-                DispatchQueue.main.async {
-                    if let callback = self.loadingTasks[key] {
-                        callback(image)
+                    if let image = image {
+                        if let callback = self.loadingTasks.removeValue(forKey: key) {
+                            callback(image)
+                        }
                     }
                 }
             }
 
-            if token.isCancelled { finish(); return }
+            if token.isCancelled { finish(nil); return }
 
-            func extractData() -> Data {
-                var extractedData = Data()
-                if self.archives.object(forKey: archiveURL.lastPathComponent as NSString) == nil {
-                    let archive = try! Archive(url: archiveURL, accessMode: .read)
-                    self.archives.setObject(archive, forKey: archiveURL.lastPathComponent as NSString)
-                }
-                let archive = self.archives.object(forKey: archiveURL.lastPathComponent as NSString)!
-                _ = try! archive.extract(archive[filename]!) { data in
-                    extractedData.append(data)
-                }
-                return extractedData
+            var extractedData = Data()
+            if self.archives.object(forKey: archiveURL.lastPathComponent as NSString) == nil {
+                let archive = try! Archive(url: archiveURL, accessMode: .read)
+                self.archives.setObject(archive, forKey: archiveURL.lastPathComponent as NSString)
+            }
+            let archive = self.archives.object(forKey: archiveURL.lastPathComponent as NSString)!
+            _ = try! archive.extract(archive[filename]!) { data in
+                extractedData.append(data)
             }
 
-            if token.isCancelled { finish(); return }
+            if token.isCancelled { finish(nil); return }
 
-            guard let image = cache.object(forKey: key as NSString) ?? UIImage(data: extractData()) else {
-                finish()
+            guard var image = UIImage(data: extractedData) else {
+                finish(nil)
                 return
             }
 
-            self.cache.setObject(image, forKey: filename as NSString, cost: imageByteSize(image)!)
+            if token.isCancelled { finish(nil); return }
 
-            if token.isCancelled { finish(); return }
+            // If you turn pages fast, completion will not be nil and as such only the needed scaled image should be prepared
+            if completion == nil || rotation == .vertical {
+                let vertical = CGSize(
+                    width: min(screenSize.width, screenSize.height),
+                    height: max(screenSize.height, screenSize.width)
+                )
+                let vScaledSize = aspectSize(for: image.size, in: vertical, scaling: scaling)
+                let vScaleImage = resizeImage(image, to: vScaledSize)
+                if let cost = imageByteSize(vScaleImage) {
+                    self.cache.setObject(vScaleImage, forKey: filename as NSString, cost: cost)
+                }
+                if rotation == .vertical { image = vScaleImage }
+            }
 
-            let scaledImage = scaleAndCacheImage(
-                image: image,
-                orientation: rotation,
-                screenSize: screenSize,
-                scaling: scaling,
-                filename: key,
-            )
+            if token.isCancelled { finish(nil); return }
 
-            if token.isCancelled { finish(); return }
+            if completion == nil || rotation == .horizontal {
+                let horizontal = CGSize(
+                    width: max(screenSize.width, screenSize.height),
+                    height: min(screenSize.height, screenSize.width)
+                )
+                let hScaledSize = aspectSize(for: image.size, in: horizontal, scaling: scaling)
+                let hScaleImage = resizeImage(image, to: hScaledSize)
+                if let cost = imageByteSize(hScaleImage) {
+                    self.horCache.setObject(hScaleImage, forKey: filename as NSString, cost: cost)
+                }
+                if rotation == .horizontal { image = hScaleImage }
+            }
 
-            setImage(scaledImage)
-
-            let otherOrientation: Rotation = rotation == .vertical ? .horizontal : .vertical
-
-            _ = scaleAndCacheImage(
-                image: image,
-                orientation: otherOrientation,
-                screenSize: screenSize,
-                scaling: scaling,
-                filename: key,
-            )
-            finish()
+            finish(image)
         }
     }
 
-    func scaleAndCacheImage(image: UIImage, orientation: Rotation, screenSize: CGSize, scaling: UIView.ContentMode, filename: String) -> UIImage {
-        let resizeTo: CGSize = if orientation == .vertical {
-            CGSize(
-                width: min(screenSize.width, screenSize.height),
-                height: max(screenSize.height, screenSize.width)
-            )
-        } else {
-            CGSize(
-                width: max(screenSize.width, screenSize.height),
-                height: min(screenSize.height, screenSize.width)
-            )
-        }
-        let scaledSize = aspectSize(for: image.size, in: resizeTo, scaling: scaling)
-        let scaledImage = resizeImage(image, to: scaledSize)
-        let cost = imageByteSize(scaledImage)!
-        switch ((orientation, scaling)) {
-            case (.vertical, .scaleAspectFit):
-                self.portraitFitCache.setObject(scaledImage, forKey: filename as NSString, cost: cost)
-            case (.vertical, .scaleAspectFill):
-                self.portraitFillCache.setObject(scaledImage, forKey: filename as NSString, cost: cost)
-            case (.horizontal, .scaleAspectFit):
-                self.landscapeFitCache.setObject(scaledImage, forKey: filename as NSString, cost: cost)
-            case (.horizontal, .scaleAspectFill):
-                self.landscapeFillCache.setObject(scaledImage, forKey: filename as NSString, cost: cost)
-            default:
-                assertionFailure()
-        }
-        return scaledImage
-    }
-
     func setActiveWindow(_ paths: [String]) {
         let desired = Set(paths)
         for (key, token) in activeTokens where !desired.contains(key) {
@@ -1714,6 +1696,10 @@ class ImageLoader {
             loadingTasks[key] = nil
         }
     }
+
+    func imageIfLoaded(at path: String) -> UIImage? {
+        return cache.object(forKey: path as NSString)
+    }
 }
 
 func imageByteSize(_ image: UIImage) -> Int? {

run.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env sh
 
-set -e
+set -eu
 
 APP_NAME='ImageViewer'
 SIM_DEVICE='iPad (A16)'