Revisit guided navigation tree

Author: qnga

demos/navigator/src/main/java/org/readium/demo/navigator/DemoViewModel.kt

@@ -23,6 +23,7 @@ import org.readium.demo.navigator.reader.SelectNavigatorItem
 import org.readium.demo.navigator.reader.SelectNavigatorViewModel
 import org.readium.demo.navigator.reader.fixedConfig
 import org.readium.demo.navigator.reader.reflowableConfig
+import org.readium.navigator.media.readaloud.NullTtsEngineProvider
 import org.readium.navigator.media.readaloud.ReadAloudNavigatorFactory
 import org.readium.navigator.web.fixedlayout.FixedWebRenditionFactory
 import org.readium.navigator.web.reflowable.ReflowableWebRenditionFactory
@@ -127,7 +128,8 @@ class DemoViewModel(
                 ReadAloudNavigatorFactory(
                     application = application,
                     publication = publication,
-                    audioEngineProvider = audioEngineProvider
+                    audioEngineProvider = audioEngineProvider,
+                    ttsEngineProvider = NullTtsEngineProvider
                 )?.let { SelectNavigatorItem.ReadAloud(it) }
 
             val factories = listOfNotNull(

demos/navigator/src/main/java/org/readium/demo/navigator/reader/ReaderOpener.kt

@@ -27,6 +27,7 @@ import org.readium.navigator.common.PreferencesEditor
 import org.readium.navigator.common.Settings
 import org.readium.navigator.common.SettingsController
 import org.readium.navigator.media.readaloud.ReadAloudNavigatorFactory
+import org.readium.navigator.media.readaloud.ReadAloudSettings
 import org.readium.navigator.web.fixedlayout.FixedWebGoLocation
 import org.readium.navigator.web.fixedlayout.FixedWebLocation
 import org.readium.navigator.web.fixedlayout.FixedWebRenditionController
@@ -40,10 +41,12 @@ import org.readium.navigator.web.reflowable.ReflowableWebRenditionFactory
 import org.readium.navigator.web.reflowable.ReflowableWebSelectionLocation
 import org.readium.navigator.web.reflowable.preferences.ReflowableWebPreferences
 import org.readium.r2.shared.ExperimentalReadiumApi
+import org.readium.r2.shared.guided.GuidedNavigationRole
 import org.readium.r2.shared.publication.Locator
 import org.readium.r2.shared.publication.Publication
 import org.readium.r2.shared.util.AbsoluteUrl
 import org.readium.r2.shared.util.Error
+import org.readium.r2.shared.util.Language
 import org.readium.r2.shared.util.Try
 import org.readium.r2.shared.util.getOrElse
 
@@ -197,7 +200,18 @@ class ReaderOpener(
         navigatorFactory: ReadAloudNavigatorFactory,
         initialLocator: Locator?,
     ): Try<ReadAloudReaderState, Error> {
-        val navigator = navigatorFactory.createNavigator()
+        val initialSettings = ReadAloudSettings(
+            language = Language("en"),
+            overrideContentLanguage = true,
+            preferRecordedVoices = true,
+            pitch = 1.0,
+            speed = 1.0,
+            voices = emptyMap(),
+            escapableRoles = GuidedNavigationRole.ESCAPABLE_ROLES.toSet(),
+            skippableRoles = GuidedNavigationRole.SKIPPABLE_ROLES.toSet()
+        )
+
+        val navigator = navigatorFactory.createNavigator(initialSettings)
             .getOrElse { return Try.failure(it) }
 
         val readerState = ReadAloudReaderState(

readium/adapters/exoplayer/readaloud/src/main/java/org/readium/adapter/exoplayer/readaloud/ExoPlayerEngine.kt

@@ -59,6 +59,8 @@ public class ExoPlayerEngine private constructor(
                 .setHandleAudioBecomingNoisy(true)
                 .build()
 
+            exoPlayer.preloadConfiguration = ExoPlayer.PreloadConfiguration(10_000_000L)
+
             return ExoPlayerEngine(exoPlayer, listener)
         }
     }
@@ -76,11 +78,11 @@ public class ExoPlayerEngine private constructor(
                     Player.STATE_ENDED -> AudioEngine.State.Ended
                     else -> null
                 }
-                newState?.let { this@ExoPlayerEngine.listener.onStateChanged(it) }
+                newState?.let { this@ExoPlayerEngine.listener.onStateChanged(this@ExoPlayerEngine, it) }
             }
 
             if (events.contains(Player.EVENT_MEDIA_ITEM_TRANSITION)) {
-                this@ExoPlayerEngine.listener.onItemChanged(player.currentMediaItemIndex)
+                this@ExoPlayerEngine.listener.onItemChanged(this@ExoPlayerEngine, player.currentMediaItemIndex)
             }
         }
     }
@@ -128,6 +130,10 @@ public class ExoPlayerEngine private constructor(
         }
     }
 
+    override fun seekTo(index: Int) {
+        exoPlayer.seekTo(index, 0L)
+    }
+
     override var playWhenReady: Boolean
         get() = exoPlayer.playWhenReady
         set(value) {

readium/navigators/media/readaloud/src/main/java/org/readium/navigator/media/readaloud/AudioEngine.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2025 Readium Foundation. All rights reserved.
+ * Use of this source code is governed by the BSD-style license
+ * available in the top-level LICENSE file of the project.
+ */
+
+@file:OptIn(ExperimentalReadiumApi::class)
+
+package org.readium.navigator.media.readaloud
+
+import org.readium.r2.shared.ExperimentalReadiumApi
+import org.readium.r2.shared.publication.services.GuidedNavigationIterator
+import org.readium.r2.shared.publication.services.GuidedNavigationService
+
+internal class ContentIteratorGuidedNavigationService : GuidedNavigationService {
+
+    override fun iterator(): GuidedNavigationIterator {
+        TODO("Not yet implemented")
+    }
+}

readium/navigators/media/readaloud/src/main/java/org/readium/navigator/media/readaloud/ContentIteratorGuidedNavigationService.kt

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2025 Readium Foundation. All rights reserved.
+ * Use of this source code is governed by the BSD-style license
+ * available in the top-level LICENSE file of the project.
+ */
+
+@file:OptIn(ExperimentalReadiumApi::class)
+
+package org.readium.navigator.media.readaloud
+
+import kotlin.properties.Delegates
+import org.readium.r2.shared.ExperimentalReadiumApi
+
+internal class ReadAloudDataLoader(
+    private val segmentFactory: ReadAloudSegmentFactory,
+    initialSettings: ReadAloudSettings,
+) {
+
+    sealed interface NodeInfo
+
+    data class ItemRef(
+        val segment: ReadAloudSegment,
+        val nodeIndex: Int?,
+    ) : NodeInfo
+
+    data object EmptyNode : NodeInfo
+
+    var settings by Delegates.observable(initialSettings) { property, oldValue, newValue ->
+        preloadedRefs.clear()
+    }
+
+    private val preloadedRefs: MutableMap<ReadAloudNode, ItemRef> = mutableMapOf()
+
+    fun onPlaybackProgressed(node: ReadAloudNode) {
+        val nextNode = node.next() ?: return
+
+        if (nextNode !in preloadedRefs) {
+            loadSegmentForNode(nextNode)
+        }
+    }
+
+    fun getItemRef(node: ReadAloudNode): ItemRef? {
+        loadSegmentForNode(node)
+        return preloadedRefs[node]
+    }
+
+    private fun loadSegmentForNode(node: ReadAloudNode) {
+        if (node in preloadedRefs) {
+            return
+        }
+
+        val segment = segmentFactory.createSegmentFromNode(node)
+            ?: return // Ended
+
+        val refs = computeRefsForSegment(segment)
+        preloadedRefs.putAll(refs)
+    }
+
+    private fun computeRefsForSegment(segment: ReadAloudSegment): Map<ReadAloudNode, ItemRef> {
+        val plainRefs = segment.nodes
+            .withIndex()
+            .associate { (index, node) -> node to ItemRef(segment, index) }
+
+        val emptyRefs = segment.emptyNodes.associateWith { ItemRef(segment, null) }
+
+        return plainRefs + emptyRefs
+    }
+}