ImageViewer/ViewController.swift

@@ -689,8 +689,6 @@ 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()
         }
     }
 
@@ -1569,16 +1567,20 @@ enum Rotation {
 }
 
 class ImageLoader {
-    private let cache = NSCache<NSString, UIImage>()
+    private let portraitFitCache = NSCache<NSString, UIImage>()
-    private let horCache = NSCache<NSString, UIImage>()
+    private let landscapeFitCache = NSCache<NSString, UIImage>()
+    private let portraitFillCache = NSCache<NSString, UIImage>()
+    private let landscapeFillCache = NSCache<NSString, UIImage>()
     private var loadingTasks: [String: (UIImage?) -> Void] = [:]
     private var activeTokens: [String: CancellationToken] = [:]
-    private var archives = NSCache<NSString, Archive>()
+    private let archives = NSCache<NSString, Archive>()
 
     init() {
         // 128 MiB
-        cache.totalCostLimit = 128 * 1024 * 1024
+        portraitFitCache.totalCostLimit = 128 * 1024 * 1024
-        horCache.totalCostLimit = 128 * 1024 * 1024
+        landscapeFitCache.totalCostLimit = 128 * 1024 * 1024
+        portraitFillCache.totalCostLimit = 128 * 1024 * 1024
+        landscapeFillCache.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
     }
@@ -1587,7 +1589,6 @@ 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,
@@ -1597,11 +1598,23 @@ class ImageLoader {
         let rotation: Rotation = screenSize.width > screenSize.height ? .horizontal : .vertical
         let key = filename
 
-        if rotation == .vertical, let cached = cache.object(forKey: key as NSString) {
+        if scaling == .scaleAspectFit {
-            completion?(cached); return
+            if rotation == .vertical, let cached = portraitFitCache.object(forKey: key as NSString) {
-        }
+                completion?(cached); return
-        if rotation == .horizontal, let cached = horCache.object(forKey: key as NSString) {
+            }
-            completion?(cached); return
+            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 {
+            print("this should not be reachable")
+            return
         }
 
         if let existing = activeTokens[key], !existing.isCancelled {
@@ -1662,8 +1675,14 @@ class ImageLoader {
                 )
                 let vScaledSize = aspectSize(for: image.size, in: vertical, scaling: scaling)
                 let vScaleImage = resizeImage(image, to: vScaledSize)
-                if let cost = imageByteSize(vScaleImage) {
+                let cost = imageByteSize(vScaleImage)!
-                    self.cache.setObject(vScaleImage, forKey: filename as NSString, cost: cost)
+                if scaling == .scaleAspectFit {
+                    self.portraitFitCache.setObject(vScaleImage, forKey: filename as NSString, cost: cost) 
+                } else if scaling == .scaleAspectFill {
+                    self.portraitFillCache.setObject(vScaleImage, forKey: filename as NSString, cost: cost)
+                } else {
+                    print("this should be unreachable")
+                    return
                 }
                 if rotation == .vertical { image = vScaleImage }
             }
@@ -1677,8 +1696,14 @@ class ImageLoader {
                 )
                 let hScaledSize = aspectSize(for: image.size, in: horizontal, scaling: scaling)
                 let hScaleImage = resizeImage(image, to: hScaledSize)
-                if let cost = imageByteSize(hScaleImage) {
+                let cost = imageByteSize(hScaleImage)!
-                    self.horCache.setObject(hScaleImage, forKey: filename as NSString, cost: cost)
+                if scaling == .scaleAspectFit {
+                    self.landscapeFitCache.setObject(hScaleImage, forKey: filename as NSString, cost: cost)
+                } else if scaling == .scaleAspectFill {
+                    self.landscapeFillCache.setObject(hScaleImage, forKey: filename as NSString, cost: cost)
+                } else {
+                    print("this should be unreachable")
+                    return
                 }
                 if rotation == .horizontal { image = hScaleImage }
             }
@@ -1694,10 +1719,6 @@ class ImageLoader {
             loadingTasks[key] = nil
         }
     }
-
-    func imageIfLoaded(at path: String) -> UIImage? {
-        return cache.object(forKey: path as NSString)
-    }
 }
 
 func imageByteSize(_ image: UIImage) -> Int? {