scrolling wip with perf problems

ImageViewer/ViewController.swift

@@ -1,7 +1,7 @@
 //TODO: Implement support for bonus chapters
-//TODO: Implement scrolling support
 //TODO: Implement Anilist support?
-//TODO: Evict the oldest image from cache
+//TODO: Properly avoid swallowing of input from UICollectionView used for scrolling
+//TODO: Fix UICollectionView sizeForItemAt method performance either by caching or lazy loading
 
 import UIKit
 
@@ -12,6 +12,12 @@ enum PageTurn {
     case previous
 }
 
+enum ReadProgress: Codable {
+    case leftToRight(chapter: Int, page: Int)
+    case rightToLeft(chapter: Int, page: Int)
+    case scroll(CGPoint)
+}
+
 enum PageTurnMode: Codable {
     case leftToRight
     case rightToLeft
@@ -29,9 +35,7 @@ struct GlobalState: Codable {
 }
 
 struct LocalState: Codable {
-    var chapter: Int
+    var progress: ReadProgress
-    var page: Int
-    var turnMode: PageTurnMode = .leftToRight
     var backgroundColor: String = "black"
 }
 
@@ -53,7 +57,7 @@ struct Metadata: Decodable {
 struct ChapterMetadata: Decodable {
     var chapter: Float
     var volume: Float
-    var title: String
+    var title: String?
     var pages: Int
 }
 
@@ -61,6 +65,11 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     var homeView = UIView()
     var readerView = UIView()
 
+    @IBOutlet var scrollingCollectionView: UICollectionView!
+    var scrollPos: CGPoint!
+    var hasSetContentOffset = false
+    var pageCount = 0
+
     var imageView = UIImageView()
     var mode = PageTurnMode.leftToRight
     var metadata: Metadata!
@@ -71,6 +80,9 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     var leftTap: UITapGestureRecognizer!
     var rightTap: UITapGestureRecognizer!
     var topTap: UITapGestureRecognizer!
+    let leftView = UIView()
+    let rightView = UIView()
+    let topView = UIView()
 
     let topBarView = UIView()
     let bottomBarView = UIView()
@@ -90,7 +102,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     let documentsURL = getDocumentsURL().unsafelyUnwrapped
 
     var comics: [Comic] = []
-    var collectionView: UICollectionView!
+    @IBOutlet var comicCollectionView: UICollectionView!
 
     let imageLoader = ImageLoader.init()
 
@@ -133,6 +145,7 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         ])
         loadComics()
         setupImageView()
+        setupScrollingCollectionView()
         setupGestures()
         setupBar()
         setupHomeView()
@@ -147,13 +160,14 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         layout.minimumInteritemSpacing = spacing
         layout.minimumLineSpacing = spacing
 
-        collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: layout)
+        comicCollectionView = UICollectionView(frame: view.bounds, collectionViewLayout: layout)
-        collectionView.translatesAutoresizingMaskIntoConstraints = false
+        comicCollectionView.translatesAutoresizingMaskIntoConstraints = false
-        collectionView.dataSource = self
+        comicCollectionView.dataSource = self
-        collectionView.delegate = self
+        comicCollectionView.delegate = self
-        collectionView.backgroundColor = .white
+        comicCollectionView.backgroundColor = .white
-        collectionView.register(ImageCell.self, forCellWithReuseIdentifier: "ImageCell")
+        comicCollectionView.register(
-        homeView.addSubview(collectionView)
+            ComicImageCell.self, forCellWithReuseIdentifier: "ComicImageCell")
+        homeView.addSubview(comicCollectionView)
     }
 
     func loadComics() {
@@ -230,13 +244,20 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
 
     func saveLocalState() {
         let color = readerView.backgroundColor ?? .black
+        let progress: ReadProgress =
+            switch self.mode {
+            case .leftToRight:
+                ReadProgress.leftToRight(chapter: self.currentChapter, page: self.currentPage)
+            case .rightToLeft:
+                ReadProgress.leftToRight(chapter: self.currentChapter, page: self.currentPage)
+            case .scroll: ReadProgress.scroll(scrollingCollectionView.contentOffset)
+            }
         localStateQueue.async {
             do {
                 try JSONEncoder().encode(
                     LocalState(
-                        chapter: self.currentChapter, page: self.currentPage, turnMode: self.mode,
+                        progress: progress, backgroundColor: self.convertColorToString(color: color)
-                        backgroundColor: self.convertColorToString(
+                    )
-                            color: color))
                 ).write(
                     to: self.currentPath.appendingPathComponent("state.json"))
             } catch {
@@ -252,9 +273,21 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                     contentsOfFile: currentPath.appendingPathComponent("state.json").path
                 ).utf8)
             let local = try JSONDecoder().decode(LocalState.self, from: json)
-            currentPage = local.page
+            switch local.progress {
-            currentChapter = local.chapter
+            case .leftToRight(let chapter, let page):
-            mode = local.turnMode
+                self.currentChapter = chapter
+                self.currentPage = page
+                self.mode = .leftToRight
+            case .rightToLeft(let chapter, let page):
+                self.currentChapter = chapter
+                self.currentPage = page
+                self.mode = .rightToLeft
+            case .scroll(let point):
+                if self.scrollPos == nil {
+                    self.scrollPos = point
+                }
+                self.mode = .scroll
+            }
             readerView.backgroundColor = convertStringToColor(str: local.backgroundColor)
         } catch {
             print("failed to load local state")
@@ -273,6 +306,36 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         setupTapZones()
     }
 
+    func scrollViewDidScroll(_ scrollView: UIScrollView) {
+        if scrollingCollectionView.isHidden { return }
+        let centerPoint = CGPoint(
+            x: scrollingCollectionView.bounds.midX + scrollingCollectionView.contentOffset.x,
+            y: scrollingCollectionView.bounds.midY + scrollingCollectionView.contentOffset.y)
+
+        if let indexPath = scrollingCollectionView.indexPathForItem(at: centerPoint) {
+            var index = 0
+            var (chapter, page) = (1, 1)
+            while index < indexPath.item {
+                (chapter, page) = getChapterAndPageFromTurn(
+                    chapter: chapter, page: page, turn: .next)
+                index += 1
+            }
+            currentChapter = chapter
+            currentPage = page
+        }
+        if scrollingCollectionView.isHidden == false {
+            saveLocalState()
+        }
+    }
+
+    override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        if scrollingCollectionView.isHidden == false && mode == .scroll && !hasSetContentOffset {
+            scrollingCollectionView.setContentOffset(scrollPos, animated: false)
+            hasSetContentOffset = true
+        }
+    }
+
     func readComic(name: String) {
         readerView.isHidden = false
         homeView.isHidden = true
@@ -280,18 +343,50 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         if let path = getPathFromComicName(name: name) {
             currentPath = path
             metadata = getMetadata(path: path)!
+            pageCount = metadata.chapters.map { $0.pages }.reduce(0, +)
             globalState.comicName = metadata.title
             saveGlobalState()
             loadLocalState()
-            setImages(path: path, metadata: metadata)
+            if mode != .scroll {
+                scrollingCollectionView.isHidden = true
+                leftView.isHidden = false
+                rightView.isHidden = false
+                setImages(path: path, metadata: metadata)
+            } else {
+                leftView.isHidden = true
+                rightView.isHidden = true
+                scrollingCollectionView.isHidden = false
+                scrollingCollectionView.reloadData()
+            }
         }
     }
 
-    func setupTapZones() {
+    func setupScrollingCollectionView() {
-        let leftView = UIView()
+        let layout = UICollectionViewFlowLayout()
-        let rightView = UIView()
+        layout.minimumInteritemSpacing = 0
-        let topView = UIView()
+        layout.minimumLineSpacing = 0
+        scrollingCollectionView = UICollectionView(
+            frame: view.bounds, collectionViewLayout: layout)
+        scrollingCollectionView.translatesAutoresizingMaskIntoConstraints = false
+        scrollingCollectionView.isUserInteractionEnabled = true
+        scrollingCollectionView.dataSource = self
+        scrollingCollectionView.delegate = self
+        scrollingCollectionView.backgroundColor = .white
+        scrollingCollectionView.isHidden = true
+        scrollingCollectionView.register(
+            ScrollingImageCell.self, forCellWithReuseIdentifier: "ScrollingImageCell")
+        readerView.addSubview(scrollingCollectionView)
 
+        NSLayoutConstraint.activate([
+            scrollingCollectionView.topAnchor.constraint(equalTo: readerView.topAnchor),
+            scrollingCollectionView.leadingAnchor.constraint(equalTo: readerView.leadingAnchor),
+            scrollingCollectionView.trailingAnchor.constraint(equalTo: readerView.trailingAnchor),
+            scrollingCollectionView.heightAnchor.constraint(equalTo: readerView.heightAnchor),
+        ])
+
+    }
+
+    func setupTapZones() {
         leftView.translatesAutoresizingMaskIntoConstraints = false
         rightView.translatesAutoresizingMaskIntoConstraints = false
         topView.translatesAutoresizingMaskIntoConstraints = false
@@ -370,6 +465,10 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         info.textColor = .white
         bottomBarView.addSubview(info)
         NSLayoutConstraint.activate([
+            info.topAnchor.constraint(equalTo: bottomBarView.topAnchor),
+            info.bottomAnchor.constraint(equalTo: bottomBarView.bottomAnchor),
+            info.leadingAnchor.constraint(equalTo: bottomBarView.leadingAnchor),
+            info.trailingAnchor.constraint(equalTo: bottomBarView.trailingAnchor),
             info.centerXAnchor.constraint(equalTo: bottomBarView.centerXAnchor),
             info.centerYAnchor.constraint(equalTo: bottomBarView.centerYAnchor),
         ])
@@ -543,10 +642,17 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
             switch title.lowercased() {
             case "left to right": mode = .leftToRight
             case "right to left": mode = .rightToLeft
-            case "scroll": mode = .scroll
+            case "scroll":
+                if mode != .scroll {
+                    scrollingCollectionView.reloadData()
+                }
+                mode = .scroll
             default: break
             }
         }
+        scrollingCollectionView.isHidden = mode != .scroll
+        leftView.isHidden = mode == .scroll
+        rightView.isHidden = mode == .scroll
         togglePageTurnDropdown()
         saveLocalState()
     }
@@ -574,16 +680,23 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         backgroundColorDropdownView.isHidden.toggle()
     }
 
+    // func gestureRecognizer(
+    //     _ gestureRecognizer: UIGestureRecognizer,
+    //     shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer
+    // ) -> Bool {
+    //     if gestureRecognizer == leftTap || gestureRecognizer == rightTap,
+    //         otherGestureRecognizer == topTap
+    //     {
+    //         return true
+    //     }
+    //     return false
+    // }
+
     func gestureRecognizer(
         _ gestureRecognizer: UIGestureRecognizer,
-        shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer
+        shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer
     ) -> Bool {
-        if gestureRecognizer == leftTap || gestureRecognizer == rightTap,
+        return true
-            otherGestureRecognizer == topTap
-        {
-            return true
-        }
-        return false
     }
 
     func toggleBar() {
@@ -596,6 +709,20 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         }
     }
 
+    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
+        if scrollingCollectionView.isHidden { return }
+        updateInfo()
+        saveLocalState()
+    }
+
+    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
+        if scrollingCollectionView.isHidden { return }
+        if !decelerate {
+            updateInfo()
+        }
+        saveLocalState()
+    }
+
     func hideBar() {
         topBarView.isHidden = true
         bottomBarView.isHidden = true
@@ -690,14 +817,26 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     }
 
     func updateInfo() {
-        info.text = """
+        if metadata == nil { return }
-            \(metadata.title)
+        if currentChapter == nil || currentPage == nil { return }
-            \(metadata.chapters[currentChapter - 1].title)
+
-            Volume \(Int(metadata.chapters[currentChapter - 1].volume)) of \(Int(metadata.last_volume))
+        var text = "\(metadata.title)\n"
-            Chapter \(currentChapter!) of \(Int(metadata.last_chapter))
+
-            Page \(currentPage!) of \(metadata.chapters[currentChapter - 1].pages)
+        if let chapterTitle = metadata.chapters[currentChapter - 1].title {
-            Image size: \(Int(imageView.image!.size.width))x\(Int(imageView.image!.size.height))
+            text =
-            """
+                text + "\(chapterTitle)"
+        }
+        text =
+            text + """
+                Volume \(Int(metadata.chapters[currentChapter - 1].volume)) of \(Int(metadata.last_volume))
+                Chapter \(currentChapter!) of \(Int(metadata.last_chapter))
+                Page \(currentPage!) of \(metadata.chapters[currentChapter - 1].pages)
+                """
+        if let image = imageView.image {
+            text =
+                text + "\nImage size: \(Int(image.size.width))x\(Int(image.size.height))"
+        }
+        info.text = text
     }
 
     func getImagePath(chapter: Int, volume: Int, page: Int, path: URL) -> URL! {
@@ -706,21 +845,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         if fileManager.fileExists(atPath: modernPath.path) {
             return modernPath
         }
-        //TODO: Remove this
-        let newPath = path.appendingPathComponent(String(format: "volume_%04d", volume))
-            .appendingPathComponent(
-                String(format: "chapter_%04d_image_%04d.png", chapter, page - 1))
-        if fileManager.fileExists(atPath: newPath.path) {
-            return newPath
-        }
-        let alternatePath = path.appendingPathComponent(String(format: "volume_%04d", volume))
-            .appendingPathComponent(
-                String(format: "chapter%03d_image_%03d.png", chapter, page - 1))
-        if fileManager.fileExists(atPath: alternatePath.path) {
-            return alternatePath
-        }
-        //
-        print("Did not find image at path")
         return nil
     }
 
@@ -822,12 +946,10 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
                 currentPage = Int(path_meta[3].components(separatedBy: ".")[0])
                 if currentPage == nil {
                     print("unable to set currentPage")
+                    assert(false)
                 }
-            } else {
-                // TODO: Remove this
-                assert(path_meta[2] == "image")
-                currentPage = Int(path_meta[3].components(separatedBy: ".")[0])! + 1
             }
+            saveLocalState()
             updateInfo()
         } catch {
             print("failed to set images")
@@ -872,40 +994,139 @@ func getDocumentsURL() -> URL? {
 
 extension ViewController: UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
 
-    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int)
+    func collectionView(
+        _ collectionView: UICollectionView, numberOfItemsInSection section: Int
+    )
         -> Int
     {
-        return comics.count
+        if collectionView == comicCollectionView {
+            return comics.count
+        } else {
+            return pageCount
+        }
     }
 
     func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath)
         -> UICollectionViewCell
     {
-        let cell =
+        if collectionView == comicCollectionView {
-            collectionView.dequeueReusableCell(withReuseIdentifier: "ImageCell", for: indexPath)
+            let cell =
-            as! ImageCell
+                collectionView.dequeueReusableCell(
-        cell.imageView.image = comics[indexPath.item].cover
+                    withReuseIdentifier: "ComicImageCell", for: indexPath)
-        return cell
+                as! ComicImageCell
+            cell.imageView.image = comics[indexPath.item].cover
+            return cell
+        } else if collectionView == scrollingCollectionView {
+            let cell =
+                collectionView.dequeueReusableCell(
+                    withReuseIdentifier: "ScrollingImageCell", for: indexPath)
+                as! ScrollingImageCell
+            if metadata == nil {
+                return cell
+            }
+            var index = 0
+            var (chapter, page) = (1, 1)
+            while index < indexPath.item {
+                (chapter, page) = getChapterAndPageFromTurn(
+                    chapter: chapter, page: page, turn: .next)
+                index += 1
+            }
+            if let url = getImagePath(
+                chapter: chapter,
+                volume: Int(metadata.chapters[chapter - 1].volume),
+                page: page, path: currentPath)
+            {
+                // cell.imageView.image = UIImage(contentsOfFile: url.path)
+                imageLoader.loadImage(at: url) { image in cell.imageView.image = image }
+            }
+            return cell
+        } else {
+            assert(false)
+        }
+
+        // Xcode profiling sucks:
+        return
+            collectionView.dequeueReusableCell(
+                withReuseIdentifier: "ScrollingImageCell", for: indexPath)
+            as! ScrollingImageCell
     }
 
     func collectionView(
-        _ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
+        _ collectionView: UICollectionView,
+        layout collectionViewLayout: UICollectionViewLayout,
         sizeForItemAt indexPath: IndexPath
     ) -> CGSize {
-        let spacing: CGFloat = 8
+        if collectionView == comicCollectionView {
-        let itemsPerRow: CGFloat = 3
+            let spacing: CGFloat = 8
-        let totalSpacing = (itemsPerRow - 1) * spacing
+            let itemsPerRow: CGFloat = 3
-        let width = (collectionView.bounds.width - totalSpacing) / itemsPerRow
+            let totalSpacing = (itemsPerRow - 1) * spacing
-        return CGSize(width: width, height: width)
+            let width = (collectionView.bounds.width - totalSpacing) / itemsPerRow
+            return CGSize(width: width, height: width)
+        } else if collectionView == scrollingCollectionView {
+            if metadata == nil {
+                return CGSize()
+            }
+            var index = 0
+            var (chapter, page) = (1, 1)
+            while index < indexPath.item {
+                (chapter, page) = getChapterAndPageFromTurn(
+                    chapter: chapter, page: page, turn: .next)
+                index += 1
+            }
+            if let imagePath = getImagePath(
+                chapter: chapter,
+                volume: Int(metadata.chapters[chapter - 1].volume),
+                page: page, path: currentPath),
+                let imageSource = CGImageSourceCreateWithURL(imagePath as CFURL, nil),
+                let imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, nil)
+                    as? [CFString: Any],
+                let height = imageProperties[kCGImagePropertyPixelHeight] as? CGFloat
+            {
+                return CGSize(width: readerView.bounds.width, height: height)
+            }
+            return CGSize(width: readerView.bounds.width, height: readerView.bounds.height)
+        } else {
+            assert(false)
+        }
+        // Xcode profiling sucks:
+        return CGSize()
     }
-    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
-        let selectedComic = comics[indexPath.item]
 
-        readComic(name: selectedComic.metadata.title)
+    func collectionView(
+        _ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath
+    ) {
+        if collectionView == comicCollectionView {
+            let selectedComic = comics[indexPath.item]
+
+            readComic(name: selectedComic.metadata.title)
+        }
     }
 }
 
-class ImageCell: UICollectionViewCell {
+class ScrollingImageCell: UICollectionViewCell {
+    let imageView = UIImageView()
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        imageView.contentMode = .scaleAspectFill
+        imageView.clipsToBounds = true
+        imageView.translatesAutoresizingMaskIntoConstraints = false
+        contentView.addSubview(imageView)
+
+        NSLayoutConstraint.activate([
+            imageView.topAnchor.constraint(equalTo: contentView.topAnchor),
+            imageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
+            imageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
+            imageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
+        ])
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
+class ComicImageCell: UICollectionViewCell {
     let imageView = UIImageView()
 
     override init(frame: CGRect) {

run.sh

@@ -18,7 +18,7 @@ xcodebuild -scheme "$SCHEME" -configuration "$BUILD_TYPE" -derivedDataPath "$DER
 
 APP_PATH="$DERIVED_DATA/Build/Products/Debug-iphonesimulator/$APP_NAME.app"
 xcrun simctl install booted "$APP_PATH"
-xcrun simctl spawn booted log stream --predicate 'process == "ImageViewer"' --style syslog &
+# xcrun simctl spawn booted log stream --predicate 'process == "ImageViewer"' --style syslog &
 xcrun simctl launch booted "$COMPANY.$APP_NAME"
 
 sudo sed -i '' '/developerservices2\.apple\.com/d' /etc/hosts