Cosmetic changes

readium/navigators/web/src/main/java/org/readium/navigator/web/layout/Layout.kt

@@ -0,0 +1,94 @@
+@file:OptIn(ExperimentalReadiumApi::class)
+
+package org.readium.navigator.web.layout
+
+import org.readium.r2.navigator.preferences.ReadingProgression
+import org.readium.r2.shared.ExperimentalReadiumApi
+import org.readium.r2.shared.util.Url
+
+internal class Layout(
+    val readingProgression: ReadingProgression,
+    val spreads: List<Spread>
+) {
+
+    fun spreadIndexForPage(pageIndex: Int): Int = spreads
+        .indexOfFirst { pageIndex in it.pages.map { page -> page.index } }
+        .also { check(it != -1) }
+
+    fun pageIndexForSpread(spreadIndex: Int) =
+        when (val spread = spreads[spreadIndex]) {
+            is SingleViewportSpread ->
+                spread.page.index
+            is LeftOnlySpread ->
+                spread.page.index
+            is RightOnlySpread ->
+                spread.page.index
+            is DoubleSpread ->
+                when (readingProgression) {
+                    ReadingProgression.LTR -> spread.leftPage.index
+                    ReadingProgression.RTL -> spread.rightPage.index
+                }
+        }
+}
+
+internal data class Page(
+    val index: Int,
+    val href: Url
+)
+
+internal sealed interface Spread {
+
+    val pages: List<Page>
+
+    fun contains(href: Url): Boolean =
+        href in pages.map { it.href }
+}
+
+internal data class SingleViewportSpread(
+    val page: Page
+) : Spread {
+
+    override val pages: List<Page> get() = listOfNotNull(page)
+}
+
+internal sealed class DoubleViewportSpread(
+    override val pages: List<Page>
+) : Spread {
+    abstract val leftPage: Page?
+
+    abstract val rightPage: Page?
+
+    companion object {
+
+        operator fun invoke(leftPage: Page?, rightPage: Page?): Spread =
+            when {
+                leftPage != null && rightPage != null -> DoubleSpread(leftPage, rightPage)
+                leftPage != null -> LeftOnlySpread(leftPage)
+                rightPage != null -> RightOnlySpread(rightPage)
+                else -> throw IllegalArgumentException("Attempt to create an empty spread.")
+            }
+    }
+}
+
+internal data class LeftOnlySpread(
+    val page: Page
+) : DoubleViewportSpread(listOf(page)) {
+
+    override val leftPage: Page = page
+
+    override val rightPage: Page? = null
+}
+
+internal data class RightOnlySpread(
+    val page: Page
+) : DoubleViewportSpread(listOf(page)) {
+
+    override val leftPage: Page? = null
+
+    override val rightPage: Page = page
+}
+
+internal data class DoubleSpread(
+    override val leftPage: Page,
+    override val rightPage: Page
+) : DoubleViewportSpread(listOf(leftPage, rightPage))

readium/navigators/web/src/main/java/org/readium/navigator/web/layout/LayoutResolver.kt

@@ -5,7 +5,7 @@ import org.readium.r2.navigator.preferences.ReadingProgression
 import org.readium.r2.shared.ExperimentalReadiumApi
 import org.readium.r2.shared.publication.presentation.Presentation
 
-@ExperimentalReadiumApi
+@OptIn(ExperimentalReadiumApi::class)
 internal class LayoutResolver(
     private val readingOrder: ReadingOrder
 ) {

readium/navigators/web/src/main/java/org/readium/navigator/web/layout/ReadingOrder.kt

@@ -0,0 +1,13 @@
+package org.readium.navigator.web.layout
+
+import org.readium.r2.shared.publication.presentation.Presentation
+import org.readium.r2.shared.util.Url
+
+internal data class ReadingOrder(
+    val items: List<ReadingOrderItem>
+)
+
+internal data class ReadingOrderItem(
+    val href: Url,
+    val page: Presentation.Page?
+)

readium/navigators/web/src/main/java/org/readium/navigator/web/pager/NavigatorPager.kt

@@ -26,6 +26,8 @@ internal fun NavigatorPager(
 
     HorizontalPager(
         modifier = modifier,
+        // Pages must intercept all scroll gestures so the pager moves
+        // only through the PagerNestedScrollConnection.
         userScrollEnabled = false,
         state = state,
         beyondViewportPageCount = beyondViewportPageCount,

readium/navigators/web/src/main/java/org/readium/navigator/web/spread/DoubleViewportSpread.kt

@@ -1,3 +1,5 @@
+@file:OptIn(ExperimentalReadiumApi::class)
+
 package org.readium.navigator.web.spread
 
 import androidx.compose.foundation.layout.BoxWithConstraints
@@ -20,7 +22,6 @@ import org.readium.r2.navigator.preferences.Fit
 import org.readium.r2.shared.ExperimentalReadiumApi
 import org.readium.r2.shared.util.AbsoluteUrl
 
-@OptIn(ExperimentalReadiumApi::class)
 @Composable
 internal fun DoubleSpread(
     state: DoubleSpreadState
@@ -68,7 +69,6 @@ internal fun DoubleSpread(
     }
 }
 
-@OptIn(ExperimentalReadiumApi::class)
 internal class DoubleSpreadState(
     val htmlData: String,
     val publicationBaseUrl: AbsoluteUrl,

readium/navigators/web/src/main/java/org/readium/navigator/web/spread/SingleViewportSpread.kt

@@ -1,3 +1,5 @@
+@file:OptIn(ExperimentalReadiumApi::class)
+
 package org.readium.navigator.web.spread
 
 import androidx.compose.foundation.layout.BoxWithConstraints
@@ -20,7 +22,6 @@ import org.readium.r2.navigator.preferences.Fit
 import org.readium.r2.shared.ExperimentalReadiumApi
 import org.readium.r2.shared.util.AbsoluteUrl
 
-@OptIn(ExperimentalReadiumApi::class)
 @Composable
 internal fun SingleSpread(
     state: SingleSpreadState
@@ -68,7 +69,6 @@ internal fun SingleSpread(
     }
 }
 
-@OptIn(ExperimentalReadiumApi::class)
 internal class SingleSpreadState(
     val htmlData: String,
     val publicationBaseUrl: AbsoluteUrl,