Add FXL EPUB fit preference (#681)

Author: mickael-menu

CHANGELOG.md

@@ -13,8 +13,8 @@ All notable changes to this project will be documented in this file. Take a look
     * This callback is called before executing any navigation action.
     * Useful for hiding UI elements when the user navigates, or implementing analytics.
 * Added swipe gesture support for navigating in PDF paginated spread mode.
-* Added `fit` preference for PDF documents to control how pages are scaled within the viewport.
-    * Only effective in scroll mode. Paginated mode always uses page fit due to PDFKit limitations.
+* Added `fit` preference for fixed-layout publications (PDF and FXL EPUB) to control how pages are scaled within the viewport.
+    * In the PDF navigator, it is only effective in scroll mode. Paginated mode always uses `page` fit due to PDFKit limitations.
 
 ### Deprecated
 
@@ -32,7 +32,7 @@ All notable changes to this project will be documented in this file. Take a look
 
 * The `Fit` enum has been redesigned to fit the PDF implementation.
     * **Breaking change:** Update any code using the old `Fit` enum values.
-* The PDF navigator's content inset behavior has changed:
+* The fixed-layout navigators (PDF and FXL EPUB)'s content inset behavior has changed:
     * iPhone: Continues to apply window safe area insets (to account for notch/Dynamic Island).
     * iPad/macOS: Now displays edge-to-edge with no automatic safe area insets.
     * You can customize this behavior with `VisualNavigatorDelegate.navigatorContentInset(_:)`.

Sources/Navigator/EPUB/Assets/Static/scripts/readium-fixed-wrapper-one.js

@@ -88,11 +88,13 @@ final class EPUBFixedSpreadView: EPUBSpreadView {
         insets.right = horizontalInsets
 
         let viewportSize = bounds.inset(by: insets).size
+        let fitString = viewModel.settings.fit.rawValue
 
         webView.evaluateJavaScript("""
             spread.setViewport(
                 {'width': \(Int(viewportSize.width)), 'height': \(Int(viewportSize.height))},
-                {'top': \(Int(insets.top)), 'left': \(Int(insets.left)), 'bottom': \(Int(insets.bottom)), 'right': \(Int(insets.right))}
+                {'top': \(Int(insets.top)), 'left': \(Int(insets.left)), 'bottom': \(Int(insets.bottom)), 'right': \(Int(insets.right))},
+                '\(fitString)'
             );
         """)
     }

Sources/Navigator/EPUB/Assets/Static/scripts/readium-fixed-wrapper-two.js

@@ -1043,10 +1043,23 @@ extension EPUBNavigatorViewController: EPUBSpreadViewDelegate {
         // the application's bars.
         var insets = view.window?.safeAreaInsets ?? .zero
 
-        if publication.metadata.layout != .fixed {
+        switch publication.metadata.layout ?? .reflowable {
+        case .fixed:
+            // With iPadOS and macOS, we aim to display content edge-to-edge
+            // since there are no physical notches or Dynamic Island like on the
+            // iPhone.
+            if UIDevice.current.userInterfaceIdiom != .phone {
+                insets = .zero
+            }
+
+        case .reflowable:
             let configInset = config.contentInset(for: view.traitCollection.verticalSizeClass)
             insets.top = max(insets.top, configInset.top)
             insets.bottom = max(insets.bottom, configInset.bottom)
+
+        case .scrolled:
+            // Not supported with EPUB.
+            break
         }
 
         return insets

Sources/Navigator/EPUB/EPUBFixedSpreadView.swift

@@ -220,6 +220,7 @@ final class EPUBNavigatorViewModel: Loggable {
                 || oldSettings.verticalText != newSettings.verticalText
                 || oldSettings.scroll != newSettings.scroll
                 || oldSettings.spread != newSettings.spread
+                || oldSettings.fit != newSettings.fit
 
         // We don't commit the CSS changes if we invalidate the pagination, as
         // the resources will be reloaded anyway.

Sources/Navigator/EPUB/EPUBNavigatorViewController.swift

@@ -18,6 +18,13 @@ public struct EPUBPreferences: ConfigurablePreferences {
     /// spread).
     public var columnCount: ColumnCount?
 
+    /// Method for fitting the content of a fixed-layout publication within the
+    /// viewport.
+    ///
+    /// - `auto` or `page`: Fit entire page within viewport (default).
+    /// - `width`: Fit page width, allow vertical scrolling if needed.
+    public var fit: Fit?
+
     /// Default typeface for the text.
     public var fontFamily: FontFamily?
 
@@ -97,6 +104,7 @@ public struct EPUBPreferences: ConfigurablePreferences {
     public init(
         backgroundColor: Color? = nil,
         columnCount: ColumnCount? = nil,
+        fit: Fit? = nil,
         fontFamily: FontFamily? = nil,
         fontSize: Double? = nil,
         fontWeight: Double? = nil,
@@ -123,6 +131,7 @@ public struct EPUBPreferences: ConfigurablePreferences {
     ) {
         self.backgroundColor = backgroundColor
         self.columnCount = columnCount
+        self.fit = fit
         self.fontFamily = fontFamily
         self.fontSize = fontSize.map { max($0, 0) }
         self.fontWeight = fontWeight?.clamped(to: 0.0 ... 2.5)
@@ -152,6 +161,7 @@ public struct EPUBPreferences: ConfigurablePreferences {
         EPUBPreferences(
             backgroundColor: other.backgroundColor ?? backgroundColor,
             columnCount: other.columnCount ?? columnCount,
+            fit: other.fit ?? fit,
             fontFamily: other.fontFamily ?? fontFamily,
             fontSize: other.fontSize ?? fontSize,
             fontWeight: other.fontWeight ?? fontWeight,

Sources/Navigator/EPUB/EPUBNavigatorViewModel.swift

@@ -70,6 +70,18 @@ public final class EPUBPreferencesEditor: StatefulPreferencesEditor<EPUBPreferen
             supportedValues: [.auto, .one, .two]
         )
 
+    /// Method for fitting the content within the viewport.
+    ///
+    /// Only effective with fixed-layout publications.
+    public lazy var fit: AnyEnumPreference<Fit> =
+        enumPreference(
+            preference: \.fit,
+            setting: \.fit,
+            defaultEffectiveValue: defaults.fit ?? .auto,
+            isEffective: { [layout] _ in layout == .fixed },
+            supportedValues: [.auto, .page, .width]
+        )
+
     /// Default typeface for the text.
     ///
     /// Only effective with reflowable publications.

Sources/Navigator/EPUB/Preferences/EPUBPreferences.swift

@@ -13,6 +13,7 @@ import ReadiumShared
 public struct EPUBSettings: ConfigurableSettings {
     public var backgroundColor: Color?
     public var columnCount: ColumnCount
+    public var fit: Fit
     public var fontFamily: FontFamily?
     public var fontSize: Double
     public var fontWeight: Double?
@@ -46,6 +47,7 @@ public struct EPUBSettings: ConfigurableSettings {
     public init(
         backgroundColor: Color?,
         columnCount: ColumnCount,
+        fit: Fit,
         fontFamily: FontFamily?,
         fontSize: Double,
         fontWeight: Double?,
@@ -72,6 +74,7 @@ public struct EPUBSettings: ConfigurableSettings {
     ) {
         self.backgroundColor = backgroundColor
         self.columnCount = columnCount
+        self.fit = fit
         self.fontFamily = fontFamily
         self.fontSize = fontSize
         self.fontWeight = fontWeight
@@ -139,6 +142,9 @@ public struct EPUBSettings: ConfigurableSettings {
             columnCount: preferences.columnCount
                 ?? defaults.columnCount
                 ?? .auto,
+            fit: preferences.fit
+                ?? defaults.fit
+                ?? .auto,
             fontFamily: preferences.fontFamily,
             fontSize: preferences.fontSize
                 ?? defaults.fontSize
@@ -196,6 +202,7 @@ public struct EPUBSettings: ConfigurableSettings {
 /// See `EPUBPreferences`.
 public struct EPUBDefaults {
     public var columnCount: ColumnCount?
+    public var fit: Fit?
     public var fontSize: Double?
     public var fontWeight: Double?
     public var hyphens: Bool?
@@ -218,6 +225,7 @@ public struct EPUBDefaults {
 
     public init(
         columnCount: ColumnCount? = nil,
+        fit: Fit? = nil,
         fontSize: Double? = nil,
         fontWeight: Double? = nil,
         hyphens: Bool? = nil,
@@ -239,6 +247,7 @@ public struct EPUBDefaults {
         wordSpacing: Double? = nil
     ) {
         self.columnCount = columnCount
+        self.fit = fit
         self.fontSize = fontSize
         self.fontWeight = fontWeight
         self.hyphens = hyphens