Add option to disable horizontal swiping when EPUB scroll is true (#531)

Author: alecdhansen

CHANGELOG.md

@@ -8,6 +8,12 @@ All notable changes to this project will be documented in this file. Take a look
 
 * The Readium Swift toolkit now requires a minimum of iOS 13.4.
 
+### Added
+
+#### Navigator
+
+* The `EPUBNavigatorViewController.Configuration.disablePageTurnsWhileScrolling` property disables horizontal swipes for navigating to previous or next resources when scroll mode is enabled. When set to `true`, you must implement your own mechanism to move to the next resource (contributed by [@alecdhansen](https://github.com/readium/swift-toolkit/pull/531)).
+
 ### Changed
 
 #### Shared

Sources/Navigator/EPUB/EPUBNavigatorViewController.swift

@@ -68,6 +68,9 @@ open class EPUBNavigatorViewController: UIViewController,
         /// `UIViewController` wrapping the `EPUBNavigatorViewController`.
         public var editingActions: [EditingAction]
 
+        /// Disables horizontal page turning when scroll is enabled.
+        public var disablePageTurnsWhileScrolling: Bool
+
         /// Content insets used to add some vertical margins around reflowable EPUB publications.
         /// The insets can be configured for each size class to allow smaller margins on compact
         /// screens.
@@ -97,6 +100,7 @@ open class EPUBNavigatorViewController: UIViewController,
             preferences: EPUBPreferences = .empty,
             defaults: EPUBDefaults = EPUBDefaults(),
             editingActions: [EditingAction] = EditingAction.defaultActions,
+            disablePageTurnsWhileScrolling: Bool = false,
             contentInset: [UIUserInterfaceSizeClass: EPUBContentInsets] = [
                 .compact: (top: 20, bottom: 20),
                 .regular: (top: 44, bottom: 44),
@@ -111,6 +115,7 @@ open class EPUBNavigatorViewController: UIViewController,
             self.preferences = preferences
             self.defaults = defaults
             self.editingActions = editingActions
+            self.disablePageTurnsWhileScrolling = disablePageTurnsWhileScrolling
             self.contentInset = contentInset
             self.preloadPreviousPositionCount = preloadPreviousPositionCount
             self.preloadNextPositionCount = preloadNextPositionCount
@@ -516,7 +521,8 @@ open class EPUBNavigatorViewController: UIViewController,
         let view = PaginationView(
             frame: .zero,
             preloadPreviousPositionCount: hasPositions ? config.preloadPreviousPositionCount : 0,
-            preloadNextPositionCount: hasPositions ? config.preloadNextPositionCount : 0
+            preloadNextPositionCount: hasPositions ? config.preloadNextPositionCount : 0,
+            isScrollEnabled: isPaginationViewScrollingEnabled
         )
         view.delegate = self
         view.backgroundColor = .clear
@@ -608,6 +614,10 @@ open class EPUBNavigatorViewController: UIViewController,
 
     // MARK: - Navigator
 
+    private var isPaginationViewScrollingEnabled: Bool {
+        !(config.disablePageTurnsWhileScrolling && settings.scroll)
+    }
+
     public var presentation: VisualNavigatorPresentation {
         VisualNavigatorPresentation(
             readingProgression: settings.readingProgression,
@@ -844,6 +854,7 @@ open class EPUBNavigatorViewController: UIViewController,
         }
 
         view.backgroundColor = settings.effectiveBackgroundColor.uiColor
+        paginationView.isScrollEnabled = isPaginationViewScrollingEnabled
     }
 
     // MARK: - User interactions
@@ -902,6 +913,7 @@ open class EPUBNavigatorViewController: UIViewController,
 extension EPUBNavigatorViewController: EPUBNavigatorViewModelDelegate {
     func epubNavigatorViewModelInvalidatePaginationView(_ viewModel: EPUBNavigatorViewModel) {
         Task {
+            paginationView.isScrollEnabled = isPaginationViewScrollingEnabled
             await reloadSpreads(force: true)
         }
     }

Sources/Navigator/Toolkit/PaginationView.swift

@@ -93,9 +93,20 @@ final class PaginationView: UIView, Loggable {
 
     private let scrollView = UIScrollView()
 
-    init(frame: CGRect, preloadPreviousPositionCount: Int, preloadNextPositionCount: Int) {
+    /// Allows the scroll view to scroll.
+    var isScrollEnabled: Bool {
+        didSet { scrollView.isScrollEnabled = isScrollEnabled }
+    }
+
+    init(
+        frame: CGRect,
+        preloadPreviousPositionCount: Int,
+        preloadNextPositionCount: Int,
+        isScrollEnabled: Bool
+    ) {
         self.preloadPreviousPositionCount = preloadPreviousPositionCount
         self.preloadNextPositionCount = preloadNextPositionCount
+        self.isScrollEnabled = isScrollEnabled
 
         super.init(frame: frame)
 
@@ -105,6 +116,7 @@ final class PaginationView: UIView, Loggable {
         scrollView.isPagingEnabled = true
         scrollView.bounces = false
         scrollView.showsHorizontalScrollIndicator = false
+        scrollView.isScrollEnabled = isScrollEnabled
         addSubview(scrollView)
 
         // Adds an empty view before the scroll view to have a consistent behavior on all iOS
@@ -316,7 +328,7 @@ final class PaginationView: UIView, Loggable {
             return
         }
 
-        scrollView.isScrollEnabled = true
+        scrollView.isScrollEnabled = isScrollEnabled
         await setCurrentIndex(index, location: location)
 
         scrollView.scrollRectToVisible(CGRect(
@@ -341,17 +353,17 @@ extension PaginationView: UIScrollViewDelegate {
     }
 
     func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
-        scrollView.isScrollEnabled = true
+        scrollView.isScrollEnabled = isScrollEnabled
     }
 
     func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
         if !decelerate {
-            scrollView.isScrollEnabled = true
+            scrollView.isScrollEnabled = isScrollEnabled
         }
     }
 
     public func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
-        scrollView.isScrollEnabled = true
+        scrollView.isScrollEnabled = isScrollEnabled
 
         let currentOffset = (readingProgression == .rtl)
             ? scrollView.contentSize.width - (scrollView.contentOffset.x + scrollView.frame.width)

Sources/Shared/Toolkit/HTTP/DefaultHTTPClient.swift

@@ -429,7 +429,7 @@ public final class DefaultHTTPClient: HTTPClient, Loggable {
                 return
             }
 
-            var response = HTTPResponse(request: request, response: urlResponse, url: url)
+            let response = HTTPResponse(request: request, response: urlResponse, url: url)
 
             guard response.status.isSuccess else {
                 state = .failure(continuation: continuation, error: .errorResponse(response))

TestApp/Sources/Reader/EPUB/EPUBViewController.swift

@@ -37,7 +37,7 @@ class EPUBViewController: VisualReaderViewController<EPUBNavigatorViewController
         let navigator = try EPUBNavigatorViewController(
             publication: publication,
             initialLocation: locator,
-            config: .init(
+            config: EPUBNavigatorViewController.Configuration(
                 preferences: initialPreferences,
                 editingActions: EditingAction.defaultActions
                     .appending(EditingAction(