Image viewing

Metatext.xcodeproj/project.pbxproj

@@ -19,6 +19,9 @@
 		D0625E5D250F0B5C00502611 /* StatusContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0625E5C250F0B5C00502611 /* StatusContentConfiguration.swift */; };
 		D06B492324D4611300642749 /* KingfisherSwiftUI in Frameworks */ = {isa = PBXBuildFile; productRef = D06B492224D4611300642749 /* KingfisherSwiftUI */; };
 		D06BC5E625202AD90079541D /* ProfileViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D06BC5E525202AD90079541D /* ProfileViewController.swift */; };
+		D08B8D3D253F929E00B1EBEF /* ImageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D3C253F929E00B1EBEF /* ImageViewController.swift */; };
+		D08B8D42253F92B600B1EBEF /* ImagePageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D41253F92B600B1EBEF /* ImagePageViewController.swift */; };
+		D08B8D4A253FC36500B1EBEF /* ImageNavigationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D49253FC36500B1EBEF /* ImageNavigationController.swift */; };
 		D0A1F4F7252E7D4B004435BF /* TableViewDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0A1F4F6252E7D4B004435BF /* TableViewDataSource.swift */; };
 		D0A3C2F725390A9700739F88 /* AppPreferences+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0A3C2F625390A9700739F88 /* AppPreferences+Extensions.swift */; };
 		D0B32F50250B373600311912 /* RegistrationView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B32F4F250B373600311912 /* RegistrationView.swift */; };
@@ -116,6 +119,9 @@
 		D0666A2524C677B400F3F04B /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		D06BC5E525202AD90079541D /* ProfileViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfileViewController.swift; sourceTree = "<group>"; };
 		D085C3BB25008DEC008A6C5E /* DB */ = {isa = PBXFileReference; lastKnownFileType = folder; path = DB; sourceTree = "<group>"; };
+		D08B8D3C253F929E00B1EBEF /* ImageViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ImageViewController.swift; sourceTree = "<group>"; };
+		D08B8D41253F92B600B1EBEF /* ImagePageViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ImagePageViewController.swift; sourceTree = "<group>"; };
+		D08B8D49253FC36500B1EBEF /* ImageNavigationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ImageNavigationController.swift; sourceTree = "<group>"; };
 		D0A1F4F6252E7D4B004435BF /* TableViewDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TableViewDataSource.swift; sourceTree = "<group>"; };
 		D0A3C2F625390A9700739F88 /* AppPreferences+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "AppPreferences+Extensions.swift"; sourceTree = "<group>"; };
 		D0AD03552505814D0085A466 /* Base16 */ = {isa = PBXFileReference; lastKnownFileType = folder; path = Base16; sourceTree = "<group>"; };
@@ -297,7 +303,6 @@
 				D0F0B125251A90F400942152 /* AccountListCell.swift */,
 				D0F0B10D251A868200942152 /* AccountView.swift */,
 				D0C7D42424F76169001EBDBB /* AddIdentityView.swift */,
-				D03B1B29253818F3008F964B /* MediaPreferencesView.swift */,
 				D0C7D42324F76169001EBDBB /* CustomEmojiText.swift */,
 				D0BEB21024FA2A90001B0F04 /* EditFilterView.swift */,
 				D0BEB20424FA1107001B0F04 /* FiltersView.swift */,
@@ -307,6 +312,7 @@
 				D0B8510B25259E56004E0744 /* LoadMoreCell.swift */,
 				D0E569DF252931B100FA1D72 /* LoadMoreContentConfiguration.swift */,
 				D0E569DA2529319100FA1D72 /* LoadMoreView.swift */,
+				D03B1B29253818F3008F964B /* MediaPreferencesView.swift */,
 				D0C7D42D24F76169001EBDBB /* NotificationTypesPreferencesView.swift */,
 				D0FE1C8E253686F9003EF1EB /* PlayerView.swift */,
 				D0C7D42824F76169001EBDBB /* PostingReadingPreferencesView.swift */,
@@ -328,6 +334,9 @@
 		D0C7D43024F76169001EBDBB /* View Controllers */ = {
 			isa = PBXGroup;
 			children = (
+				D08B8D41253F92B600B1EBEF /* ImagePageViewController.swift */,
+				D08B8D49253FC36500B1EBEF /* ImageNavigationController.swift */,
+				D08B8D3C253F929E00B1EBEF /* ImageViewController.swift */,
 				D06BC5E525202AD90079541D /* ProfileViewController.swift */,
 				D0F0B12D251A97E400942152 /* TableViewController.swift */,
 			);
@@ -569,6 +578,7 @@
 				D0F0B12E251A97E400942152 /* TableViewController.swift in Sources */,
 				D0FE1C8F253686F9003EF1EB /* PlayerView.swift in Sources */,
 				D0F0B113251A86A000942152 /* AccountContentConfiguration.swift in Sources */,
+				D08B8D42253F92B600B1EBEF /* ImagePageViewController.swift in Sources */,
 				D01F41D924F880C400D55A2D /* TouchFallthroughTextView.swift in Sources */,
 				D0C7D4D624F7616A001EBDBB /* NSMutableAttributedString+Extensions.swift in Sources */,
 				D0625E59250F092900502611 /* StatusListCell.swift in Sources */,
@@ -591,9 +601,11 @@
 				D01EF22425182B1F00650C6B /* AccountHeaderView.swift in Sources */,
 				D0EA59482522B8B600804347 /* ViewConstants.swift in Sources */,
 				D0C7D49824F7616A001EBDBB /* CustomEmojiText.swift in Sources */,
+				D08B8D3D253F929E00B1EBEF /* ImageViewController.swift in Sources */,
 				D0B8510C25259E56004E0744 /* LoadMoreCell.swift in Sources */,
 				D01F41E424F8889700D55A2D /* StatusAttachmentsView.swift in Sources */,
 				D0BEB21124FA2A91001B0F04 /* EditFilterView.swift in Sources */,
+				D08B8D4A253FC36500B1EBEF /* ImageNavigationController.swift in Sources */,
 				D0030982250C6C8500EACB32 /* URL+Extensions.swift in Sources */,
 				D00CB2ED2533ACC00080096B /* StatusView.swift in Sources */,
 				D0A1F4F7252E7D4B004435BF /* TableViewDataSource.swift in Sources */,

View Controllers/ImageNavigationController.swift

@@ -0,0 +1,25 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+
+class ImageNavigationController: UINavigationController {
+    private let imagePageViewController: ImagePageViewController
+
+    init(imagePageViewController: ImagePageViewController) {
+        self.imagePageViewController = imagePageViewController
+
+        super.init(rootViewController: imagePageViewController)
+    }
+
+    @available(*, unavailable)
+    required init?(coder aDecoder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+        hidesBarsOnTap = true
+        modalPresentationStyle = .fullScreen
+    }
+}

View Controllers/ImagePageViewController.swift

@@ -0,0 +1,76 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+import ViewModels
+
+class ImagePageViewController: UIPageViewController {
+    let imageViewControllers: [ImageViewController]
+
+    init(initiallyVisible: AttachmentViewModel, statusViewModel: StatusViewModel) {
+        imageViewControllers = statusViewModel.attachmentViewModels.map(ImageViewController.init(viewModel:))
+
+        super.init(
+            transitionStyle: .scroll,
+            navigationOrientation: .horizontal,
+            options: [.interPageSpacing: CGFloat.defaultSpacing])
+
+        let index = statusViewModel.attachmentViewModels.firstIndex {
+            $0.attachment.id == initiallyVisible.attachment.id
+        }
+
+        setViewControllers([imageViewControllers[index ?? 0]], direction: .forward, animated: false)
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+        dataSource = self
+        view.backgroundColor = .secondarySystemBackground
+        view.subviews.compactMap { $0 as? UIScrollView }.first?.bounces = imageViewControllers.count > 1
+
+        navigationItem.leftBarButtonItem = .init(
+            systemItem: .close,
+            primaryAction: UIAction { [weak self] _ in self?.presentingViewController?.dismiss(animated: true) })
+
+        navigationController?.barHideOnTapGestureRecognizer.addTarget(
+            self,
+            action: #selector(toggleDescriptionVisibility))
+    }
+}
+
+extension ImagePageViewController {
+    @objc func toggleDescriptionVisibility() {
+        for controller in imageViewControllers {
+            controller.toggleDescriptionVisibility()
+        }
+    }
+}
+
+extension ImagePageViewController: UIPageViewControllerDataSource {
+    func pageViewController(_ pageViewController: UIPageViewController,
+                            viewControllerAfter viewController: UIViewController) -> UIViewController? {
+        guard
+            let imageViewController = viewController as? ImageViewController,
+            let index = imageViewControllers.firstIndex(of: imageViewController),
+            index + 1 < imageViewControllers.count
+        else { return nil }
+
+        return imageViewControllers[index + 1]
+    }
+
+    func pageViewController(_ pageViewController: UIPageViewController,
+                            viewControllerBefore viewController: UIViewController) -> UIViewController? {
+        guard
+            let imageViewController = viewController as? ImageViewController,
+            let index = imageViewControllers.firstIndex(of: imageViewController),
+            index > 0
+        else { return nil }
+
+        return imageViewControllers[index - 1]
+    }
+}

View Controllers/ImageViewController.swift

@@ -0,0 +1,169 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Kingfisher
+import UIKit
+import ViewModels
+
+class ImageViewController: UIViewController {
+    private let viewModel: AttachmentViewModel
+    private let scrollView = UIScrollView()
+    private let contentView = UIView()
+    private let imageView = AnimatedImageView()
+    private let playerView = PlayerView()
+    private let descriptionBackgroundView = UIVisualEffectView(effect: UIBlurEffect(style: .systemChromeMaterial))
+    private let descriptionTextView = UITextView()
+
+    init(viewModel: AttachmentViewModel) {
+        self.viewModel = viewModel
+
+        super.init(nibName: nil, bundle: nil)
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    // swiftlint:disable:next function_body_length
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+        view.backgroundColor = .secondarySystemBackground
+
+        view.addSubview(scrollView)
+        scrollView.delegate = self
+        scrollView.translatesAutoresizingMaskIntoConstraints = false
+        scrollView.showsHorizontalScrollIndicator = false
+        scrollView.showsVerticalScrollIndicator = false
+        scrollView.maximumZoomScale = Self.maximumZoomScale
+
+        contentView.translatesAutoresizingMaskIntoConstraints = false
+        scrollView.addSubview(contentView)
+
+        contentView.addSubview(imageView)
+        imageView.translatesAutoresizingMaskIntoConstraints = false
+        imageView.contentMode = .scaleAspectFit
+
+        contentView.addSubview(playerView)
+        playerView.translatesAutoresizingMaskIntoConstraints = false
+
+        view.addSubview(descriptionBackgroundView)
+        descriptionBackgroundView.translatesAutoresizingMaskIntoConstraints = false
+        descriptionBackgroundView.isHidden = viewModel.attachment.description == nil
+            || viewModel.attachment.description == ""
+
+        descriptionBackgroundView.contentView.addSubview(descriptionTextView)
+        descriptionTextView.translatesAutoresizingMaskIntoConstraints = false
+        descriptionTextView.backgroundColor = .clear
+        descriptionTextView.font = .preferredFont(forTextStyle: .caption1)
+        descriptionTextView.adjustsFontForContentSizeCategory = true
+        descriptionTextView.text = viewModel.attachment.description
+        descriptionTextView.isScrollEnabled = false
+        descriptionTextView.isEditable = false
+
+        NSLayoutConstraint.activate([
+            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+            scrollView.topAnchor.constraint(equalTo: view.topAnchor),
+            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
+            contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
+            contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
+            contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
+            contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
+            contentView.centerXAnchor.constraint(equalTo: scrollView.centerXAnchor),
+            contentView.centerYAnchor.constraint(equalTo: scrollView.centerYAnchor),
+            imageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
+            imageView.topAnchor.constraint(equalTo: contentView.topAnchor),
+            imageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
+            imageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
+            playerView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
+            playerView.topAnchor.constraint(equalTo: contentView.topAnchor),
+            playerView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
+            playerView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
+            descriptionBackgroundView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+            descriptionBackgroundView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+            descriptionBackgroundView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
+            descriptionTextView.leadingAnchor.constraint(
+                equalTo: descriptionBackgroundView.layoutMarginsGuide.leadingAnchor),
+            descriptionTextView.topAnchor.constraint(equalTo: descriptionBackgroundView.topAnchor),
+            descriptionTextView.trailingAnchor.constraint(
+                equalTo: descriptionBackgroundView.layoutMarginsGuide.trailingAnchor),
+            descriptionTextView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor)
+        ])
+
+        switch viewModel.attachment.type {
+        case .image:
+            playerView.isHidden = true
+            imageView.isHidden = false
+            imageView.kf.indicatorType = .activity
+            imageView.kf.setImage(
+                with: viewModel.attachment.previewUrl,
+                options: [.onlyFromCache],
+                completionHandler: { [weak self] in
+                guard let self = self else { return }
+
+                if case .success = $0 {
+                    self.imageView.kf.indicatorType = .none
+                }
+
+                self.imageView.kf.setImage(
+                    with: self.viewModel.attachment.url,
+                    options: [.keepCurrentImageWhileLoading])
+            })
+        case .gifv:
+            playerView.isHidden = false
+            imageView.isHidden = true
+            let player = PlayerCache.shared.player(url: viewModel.attachment.url)
+
+            player.isMuted = true
+
+            playerView.player = player
+            player.play()
+        default: break
+        }
+    }
+}
+
+extension ImageViewController {
+    func toggleDescriptionVisibility() {
+        UIView.animate(withDuration: .shortAnimationDuration) {
+            self.descriptionBackgroundView.alpha = self.descriptionBackgroundView.alpha > 0 ? 0 : 1
+        }
+    }
+}
+
+extension ImageViewController: UIScrollViewDelegate {
+    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
+        contentView
+    }
+
+    // https://stackoverflow.com/a/40480610/2484482
+    func scrollViewDidZoom(_ scrollView: UIScrollView) {
+        if scrollView.zoomScale > 1,
+           let contentSize = imageView.image?.size ?? playerView.player?.currentItem?.presentationSize {
+            let ratio = min(contentView.frame.width / contentSize.width, contentView.frame.height / contentSize.height)
+
+            let newWidth = contentSize.width * ratio
+            let newHeight = contentSize.height * ratio
+
+            let horizontalInset = 0.5 * (newWidth * scrollView.zoomScale > contentView.frame.width
+                                            ? (newWidth - contentView.frame.width)
+                                            : (scrollView.frame.width - scrollView.contentSize.width))
+            let verticalInset = 0.5 * (newHeight * scrollView.zoomScale > contentView.frame.height
+                                        ? (newHeight - contentView.frame.height)
+                                        : (scrollView.frame.height - scrollView.contentSize.height))
+
+            scrollView.contentInset = .init(
+                top: verticalInset,
+                left: horizontalInset,
+                bottom: verticalInset,
+                right: horizontalInset)
+        } else {
+            scrollView.contentInset = .zero
+        }
+    }
+}
+
+private extension ImageViewController {
+    static let maximumZoomScale: CGFloat = 5
+}

View Controllers/TableViewController.swift

@@ -310,7 +310,12 @@ private extension TableViewController {
                 player.play()
             }
         case .image, .gifv:
-            break
+            let imagePageViewController = ImagePageViewController(
+                initiallyVisible: attachmentViewModel,
+                statusViewModel: statusViewModel)
+            let imageNavigationController = ImageNavigationController(imagePageViewController: imagePageViewController)
+
+            present(imageNavigationController, animated: true)
         case .unknown:
             break
         }

Views/PlayerView.swift

@@ -15,8 +15,11 @@ class PlayerView: UIView {
 
     override init(frame: CGRect) {
         super.init(frame: frame)
+    }
 
-        (layer as? AVPlayerLayer)?.videoGravity = .resizeAspectFill
+    var videoGravity: AVLayerVideoGravity {
+        get { playerLayer.videoGravity }
+        set { playerLayer.videoGravity = newValue }
     }
 
     @available(*, unavailable)
@@ -24,3 +27,10 @@ class PlayerView: UIView {
         fatalError("init(coder:) has not been implemented")
     }
 }
+
+private extension PlayerView {
+    var playerLayer: AVPlayerLayer {
+        // swiftlint:disable:next force_cast
+        layer as! AVPlayerLayer
+    }
+}

Views/Status/StatusAttachmentView.swift

@@ -100,6 +100,7 @@ private extension StatusAttachmentView {
 
         addSubview(playerView)
         playerView.translatesAutoresizingMaskIntoConstraints = false
+        playerView.videoGravity = .resizeAspectFill
         playerView.isHidden = true
 
         addSubview(button)

Views/ViewConstants.swift

@@ -13,6 +13,7 @@ extension CGFloat {
 
 extension TimeInterval {
     static let defaultAnimationDuration: Self = 0.5
+    static let shortAnimationDuration = defaultAnimationDuration / 2
 }
 
 extension UIImage {