Page thumbnails in PDF reader sidebar

Zotero.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -77,8 +77,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/PSPDFKit/PSPDFKit-SP",
       "state" : {
-        "revision" : "324c9a623e879e7a1ff8aa8e1968739619ae538d",
-        "version" : "13.0.1"
+        "revision" : "fcff39b2b7741662286dc4323ea255a0ea53fcd3",
+        "version" : "13.1.0"
       }
     },
     {

Zotero/Controllers/AnnotationPreviewController.swift

@@ -38,7 +38,7 @@ final class AnnotationPreviewController: NSObject {
     let observable: PublishSubject<AnnotationPreviewUpdate>
     private let previewSize: CGSize
     private let queue: DispatchQueue
-    private let fileStorage: FileStorage
+    private unowned let fileStorage: FileStorage
 
     private var subscribers: [SubscriberKey: (SingleEvent<UIImage>) -> Void]
 
@@ -76,7 +76,17 @@ extension AnnotationPreviewController {
                 self.subscribers[subscriberKey] = subscriber
             }
 
-            self.enqueue(key: key, parentKey: parentKey, libraryId: libraryId, document: document, pageIndex: page, rect: rect, imageSize: imageSize, imageScale: imageScale, type: .temporary(subscriberKey: subscriberKey))
+            self.enqueue(
+                key: key,
+                parentKey: parentKey,
+                libraryId: libraryId,
+                document: document,
+                pageIndex: page,
+                rect: rect,
+                imageSize: imageSize,
+                imageScale: imageScale,
+                type: .temporary(subscriberKey: subscriberKey)
+            )
 
             return Disposables.create()
         }
@@ -92,13 +102,20 @@ extension AnnotationPreviewController {
 
         // Cache and report original color
         let rect = annotation.previewBoundingBox
-        self.enqueue(key: annotation.previewId, parentKey: parentKey, libraryId: libraryId, document: document, pageIndex: annotation.pageIndex,
-                     rect: rect, imageSize: previewSize, imageScale: 0.0, includeAnnotation: (annotation is PSPDFKit.InkAnnotation), invertColors: false, isDark: isDark, type: .cachedAndReported)
-//        // If in dark mode, only cache light mode version, which is required for backend upload
-//        if isDark {
-//            self.enqueue(key: key, parentKey: parentKey, document: document, pageIndex: annotation.pageIndex, rect: rect,
-//                         invertColors: true, imageSize: previewSize, imageScale: 0.0, isDark: !isDark, type: .cachedOnly)
-//        }
+        self.enqueue(
+            key: annotation.previewId,
+            parentKey: parentKey,
+            libraryId: libraryId,
+            document: document,
+            pageIndex: annotation.pageIndex,
+            rect: rect,
+            imageSize: previewSize,
+            imageScale: 0.0,
+            includeAnnotation: (annotation is PSPDFKit.InkAnnotation),
+            invertColors: false,
+            isDark: isDark,
+            type: .cachedAndReported
+        )
     }
 
     /// Deletes cached preview for given annotation.
@@ -170,30 +187,27 @@ extension AnnotationPreviewController {
     /// - parameter isDark: `true` if rendered image is in dark mode, `false` otherwise.
     /// - parameter type: Type of preview image. If `temporary`, requested image is temporary and is returned as `Single<UIImage>`. Otherwise image is
     ///                   cached locally and reported through `PublishSubject`.
-    private func enqueue(key: String, parentKey: String, libraryId: LibraryIdentifier, document: Document, pageIndex: PageIndex, rect: CGRect, imageSize: CGSize, imageScale: CGFloat, includeAnnotation: Bool = false, invertColors: Bool = false, isDark: Bool = false, type: PreviewType) {
-        /*
-         Workaround for PSPDFKit issue.
-
-         The way these render options work is that they are applied on top of the original document page colors.
-
-         So if the appearance mode of a PDFViewController is set to night mode and enabling invertRenderColor at that point for a render request of a document displayed in that PDFViewController
-         will not result into reverting the rendering back to light mode. You will have to not enable invertRenderColor option when
-         PDFViewController.appearanceModeManager.appearanceMode is set to night.
-
-         However, even while setting invertRenderColor to false with the appearance mode set to night results in the rendering to be inverted. This should not be the case. So create a dummy document
-         just for rendering and invert only when inverting from light to dark mode
-         */
-//        let newDoc = Document(url: document.fileURL!)
-
+    private func enqueue(
+        key: String,
+        parentKey: String,
+        libraryId: LibraryIdentifier,
+        document: Document,
+        pageIndex: PageIndex,
+        rect: CGRect,
+        imageSize: CGSize,
+        imageScale: CGFloat,
+        includeAnnotation: Bool = false,
+        invertColors: Bool = false,
+        isDark: Bool = false,
+        type: PreviewType
+    ) {
         var skipAnnotations = document.annotations(at: pageIndex)
         if includeAnnotation {
             skipAnnotations = skipAnnotations.filter({ $0.previewId != key })
         }
 
         let options = RenderOptions()
         options.skipAnnotationArray = skipAnnotations
-        // Color inversion disabled because of PSPDFKit rendering issues. It's not needed now, but just in case this is needed later let's keep it here.
-//        options.invertRenderColor = !invertColors && isDark
 
         let request = MutableRenderRequest(document: document)
         request.pageIndex = pageIndex

Zotero/Controllers/Architecture/ViewModel.swift

@@ -97,7 +97,7 @@ extension BackgroundDbProcessingActionHandler {
 }
 
 final class ViewModel<Handler: ViewModelActionHandler>: ObservableObject {
-    private let handler: Handler
+    let handler: Handler
     private let disposeBag: DisposeBag
 
     let objectWillChange: ObservableObjectPublisher

Zotero/Controllers/AttachmentFileCleanupController.swift

@@ -132,6 +132,8 @@ final class AttachmentFileCleanupController {
             // Annotations are not guaranteed to exist and they can be removed even if the parent PDF was not deleted due to upload state.
             // These are generated on device, so they'll just be recreated.
             try? self.fileStorage.remove(Files.annotationPreviews)
+            // Remove page thumbnails
+            try? self.fileStorage.remove(Files.pageThumbnails)
             // When removing all local files clear cache as well.
             try? self.fileStorage.remove(Files.cache)
 
@@ -169,6 +171,8 @@ final class AttachmentFileCleanupController {
             // Annotations are not guaranteed to exist and they can be removed even if the parent PDF was not deleted due to upload state.
             // These are generated on device, so they'll just be recreated.
             try? self.fileStorage.remove(Files.annotationPreviews(for: libraryId))
+            // Cleanup page thumbnails
+            try? self.fileStorage.remove(Files.pageThumbnails(for: libraryId))
 
             if let keys = deletedIndividually[libraryId], !keys.isEmpty {
                 return .allForItems(keys, libraryId)
@@ -319,5 +323,7 @@ final class AttachmentFileCleanupController {
         try self.fileStorage.remove(Files.attachmentDirectory(in: libraryId, key: key))
         // Annotations are not guaranteed to exist.
         try? self.fileStorage.remove(Files.annotationPreviews(for: key, libraryId: libraryId))
+        // Cleanup page thumbnails
+        try? self.fileStorage.remove(Files.pageThumbnails(for: key, libraryId: libraryId))
     }
 }

Zotero/Controllers/Controllers.swift

@@ -26,6 +26,7 @@ final class Controllers {
     let bundledDataStorage: DbStorage
     let translatorsAndStylesController: TranslatorsAndStylesController
     let annotationPreviewController: AnnotationPreviewController
+    let pdfThumbnailController: PDFThumbnailController
     let urlDetector: UrlDetector
     let dateParser: DateParser
     let htmlAttributedStringConverter: HtmlAttributedStringConverter
@@ -92,6 +93,7 @@ final class Controllers {
         self.debugLogging = debugLogging
         self.translatorsAndStylesController = translatorsAndStylesController
         self.annotationPreviewController = AnnotationPreviewController(previewSize: previewSize, fileStorage: fileStorage)
+        self.pdfThumbnailController = PDFThumbnailController(fileStorage: fileStorage)
         self.urlDetector = urlDetector
         self.dateParser = DateParser()
         self.htmlAttributedStringConverter = HtmlAttributedStringConverter()
@@ -280,6 +282,8 @@ final class Controllers {
         try? self.fileStorage.remove(Files.jsonCache)
         // Remove annotation preview cache
         try? self.fileStorage.remove(Files.annotationPreviews)
+        // Remove attachment page thumbnails
+        try? self.fileStorage.remove(Files.pageThumbnails)
         // Remove interrupted upload files
         try? self.fileStorage.remove(Files.uploads)
         // Remove downloaded files

Zotero/Controllers/PdfDocumentExporter.swift → Zotero/Controllers/PDFDocumentExporter.swift

@@ -1,5 +1,5 @@
 //
-//  PdfDocumentExporter.swift
+//  PDFDocumentExporter.swift
 //  Zotero
 //
 //  Created by Michal Rentka on 25.01.2021.
@@ -10,7 +10,7 @@ import UIKit
 
 import PSPDFKit
 
-struct PdfDocumentExporter {
+struct PDFDocumentExporter {
     enum Error: Swift.Error {
         case filenameMissing
         case fileError(Swift.Error)

Zotero/Controllers/PDFThumbnailController.swift

@@ -0,0 +1,154 @@
+//
+//  PDFThumbnailController.swift
+//  Zotero
+//
+//  Created by Michal Rentka on 30.11.2023.
+//  Copyright © 2023 Corporation for Digital Scholarship. All rights reserved.
+//
+
+import Foundation
+
+import CocoaLumberjackSwift
+import PSPDFKit
+import RxSwift
+
+final class PDFThumbnailController: NSObject {
+    enum Error: Swift.Error {
+        case imageNotAvailable
+    }
+
+    struct SubscriberKey: Hashable {
+        let key: String
+        let libraryId: LibraryIdentifier
+        let page: UInt
+        let size: CGSize
+        let isDark: Bool
+    }
+
+    private let queue: DispatchQueue
+    private unowned let fileStorage: FileStorage
+
+    private var subscribers: [SubscriberKey: (SingleEvent<UIImage>) -> Void]
+
+    init(fileStorage: FileStorage) {
+        self.fileStorage = fileStorage
+        self.subscribers = [:]
+        self.queue = DispatchQueue(label: "org.zotero.PdfThumbnailController.queue", qos: .userInitiated)
+        super.init()
+    }
+}
+
+// MARK: - PSPDFKit
+
+extension PDFThumbnailController {
+    /// Start rendering process of multiple thumbnails per document.
+    /// - parameter pages: Page indices which should be rendered.
+    /// - parameter 
+    func cache(pages: [UInt], key: String, libraryId: LibraryIdentifier, document: Document, imageSize: CGSize, isDark: Bool) -> Observable<()> {
+        let observables = pages.map({
+            cache(page: $0, key: key, libraryId: libraryId, document: document, imageSize: imageSize, isDark: isDark).flatMap({ _ in return Single.just(()) }).asObservable()
+        })
+        return Observable.merge(observables)
+    }
+
+    func cache(page: UInt, key: String, libraryId: LibraryIdentifier, document: Document, imageSize: CGSize, isDark: Bool) -> Single<UIImage> {
+        return Single.create { [weak self] subscriber -> Disposable in
+            guard let self else { return Disposables.create() }
+            let subscriberKey = SubscriberKey(key: key, libraryId: libraryId, page: page, size: imageSize, isDark: isDark)
+            self.queue.async(flags: .barrier) { [weak self] in
+                self?.subscribers[subscriberKey] = subscriber
+            }
+            self.enqueue(subscriberKey: subscriberKey, document: document, imageSize: imageSize)
+            return Disposables.create()
+        }
+    }
+
+    /// Deletes cached thumbnails for given PDF document.
+    /// - parameter key: Attachment item key.
+    /// - parameter libraryId: Library identifier of item.
+    func deleteAll(forKey key: String, libraryId: LibraryIdentifier) {
+        self.queue.async(flags: .barrier) { [weak self] in
+            try? self?.fileStorage.remove(Files.pageThumbnails(for: key, libraryId: libraryId))
+        }
+    }
+
+    /// Checks whether thumbnail is available for given page in document.
+    /// - parameter page: Page index..
+    /// - parameter key: Key of PDF item.
+    /// - parameter libraryId: Library identifier of item.
+    /// - parameter isDark: `true` if dark mode is on, `false` otherwise.
+    /// - returns: `true` if thumbnail is available, `false` otherwise.
+    func hasThumbnail(page: UInt, key: String, libraryId: LibraryIdentifier, isDark: Bool) -> Bool {
+        return fileStorage.has(Files.pageThumbnail(pageIndex: page, key: key, libraryId: libraryId, isDark: isDark))
+    }
+
+    /// Loads thumbnail from cached file
+    /// - parameter page: Page index.
+    /// - parameter key: Key of PDF item.
+    /// - parameter libraryId: Library identifier of item.
+    /// - parameter isDark: `true` if dark mode is on, `false` otherwise.
+    /// - returns: UIImage of given page thumbnail.
+    func thumbnail(page: UInt, key: String, libraryId: LibraryIdentifier, isDark: Bool) -> UIImage? {
+        do {
+            let data = try fileStorage.read(Files.pageThumbnail(pageIndex: page, key: key, libraryId: libraryId, isDark: isDark))
+            return try UIImage(imageData: data)
+        } catch let error {
+            DDLogError("PdfThumbnailController: can't load thumbnail - \(error)")
+            return nil
+        }
+    }
+
+    /// Creates and enqueues a render request for PSPDFKit rendering engine.
+    /// - parameter subscriberKey: Subscriber key identifying this request.
+    /// - parameter document: Document to render.
+    /// - parameter imageSize: Size of rendered image.
+    private func enqueue(subscriberKey: SubscriberKey, document: Document, imageSize: CGSize) {
+        let request = MutableRenderRequest(document: document)
+        request.pageIndex = subscriberKey.page
+        request.imageSize = imageSize
+        request.options = RenderOptions()
+
+        do {
+            let task = try RenderTask(request: request)
+            task.priority = .userInitiated
+            task.completionHandler = { [weak self] image, error in
+                let result: Result<UIImage, Swift.Error> = image.flatMap({ .success($0) }) ?? .failure(error ?? Error.imageNotAvailable)
+                self?.queue.async(flags: .barrier) {
+                    self?.completeRequest(with: result, subscriberKey: subscriberKey)
+                }
+            }
+            PSPDFKit.SDK.shared.renderManager.renderQueue.schedule(task)
+        } catch let error {
+            DDLogError("PdfThumbnailController: can't create task - \(error)")
+        }
+    }
+
+    private func completeRequest(with result: Result<UIImage, Swift.Error>, subscriberKey: SubscriberKey) {
+        switch result {
+        case .success(let image):
+            perform(event: .success(image), subscriberKey: subscriberKey)
+            cache(image: image, page: subscriberKey.page, key: subscriberKey.key, libraryId: subscriberKey.libraryId, isDark: subscriberKey.isDark)
+
+        case .failure(let error):
+            DDLogError("PdfThumbnailController: could not generate image - \(error)")
+            perform(event: .failure(error), subscriberKey: subscriberKey)
+        }
+
+        func perform(event: SingleEvent<UIImage>, subscriberKey: SubscriberKey) {
+            self.subscribers[subscriberKey]?(event)
+            self.subscribers[subscriberKey] = nil
+        }
+
+        func cache(image: UIImage, page: UInt, key: String, libraryId: LibraryIdentifier, isDark: Bool) {
+            guard let data = image.pngData() else {
+                DDLogError("PdfThumbnailController: can't create data from image")
+                return
+            }
+            do {
+                try self.fileStorage.write(data, to: Files.pageThumbnail(pageIndex: page, key: key, libraryId: libraryId, isDark: isDark), options: .atomicWrite)
+            } catch let error {
+                DDLogError("PdfThumbnailController: can't store preview - \(error)")
+            }
+        }
+    }
+}

Zotero/Models/DeletableObject.swift

@@ -114,7 +114,7 @@ extension RItem: Deletable {
             NotificationCenter.default.post(name: .attachmentDeleted, object: Files.attachmentDirectory(in: libraryId, key: self.key))
 
             if contentType == "application/pdf" {
-                // This is a PDF file, remove all annotations.
+                // This is a PDF file, remove all annotations and thumbnails.
                 NotificationCenter.default.post(name: .attachmentDeleted, object: Files.annotationPreviews(for: self.key, libraryId: libraryId))
             }
         }

Zotero/Models/Files.swift

@@ -122,11 +122,31 @@ struct Files {
         return FileData(rootPath: Files.cachesRootPath, relativeComponents: ["Zotero", "sharing", key], name: name, ext: ext)
     }
 
+    static func pageThumbnail(pageIndex: UInt, key: String, libraryId: LibraryIdentifier, isDark: Bool) -> File {
+        return FileData(rootPath: Files.appGroupPath, relativeComponents: ["thumbnails", libraryId.folderName, key], name: "\(pageIndex)" + (isDark ? "_dark" : ""), contentType: "png")
+    }
+
+    static func pageThumbnails(for key: String, libraryId: LibraryIdentifier) -> File {
+        return FileData.directory(rootPath: Files.appGroupPath, relativeComponents: ["thumbnails", libraryId.folderName, key])
+    }
+
+    static func pageThumbnails(for libraryId: LibraryIdentifier) -> File {
+        return FileData.directory(rootPath: Files.appGroupPath, relativeComponents: ["thumbnails", libraryId.folderName])
+    }
+
+    static var pageThumbnails: File {
+        return FileData.directory(rootPath: Files.appGroupPath, relativeComponents: ["thumbnails"])
+    }
+
     // MARK: - Annotations
 
     static func annotationPreview(annotationKey: String, pdfKey: String, libraryId: LibraryIdentifier, isDark: Bool) -> File {
-        return FileData(rootPath: Files.appGroupPath, relativeComponents: ["annotations", libraryId.folderName, pdfKey],
-                        name: annotationKey + (isDark ? "_dark" : ""), ext: "png")
+        return FileData(
+            rootPath: Files.appGroupPath,
+            relativeComponents: ["annotations", libraryId.folderName, pdfKey],
+            name: annotationKey + (isDark ? "_dark" : ""),
+            ext: "png"
+        )
     }
 
     static func annotationPreviews(for pdfKey: String, libraryId: LibraryIdentifier) -> File {

Zotero/Scenes/Detail/PDF/Models/PDFExportState.swift

@@ -11,5 +11,5 @@ import Foundation
 enum PDFExportState {
     case preparing
     case exported(File)
-    case failed(PdfDocumentExporter.Error)
+    case failed(PDFDocumentExporter.Error)
 }