Vertical reader mode

app/src/main/kotlin/org/koitharu/kotatsu/core/prefs/ReaderMode.kt

@@ -4,7 +4,9 @@ enum class ReaderMode(val id: Int) {
 
 	STANDARD(1),
 	REVERSED(3),
-	WEBTOON(2);
+	VERTICAL(4),
+	WEBTOON(2),
+	;
 
 	companion object {
 

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/ReaderManager.kt

@@ -7,6 +7,7 @@ import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.reader.ui.pager.BaseReaderFragment
 import org.koitharu.kotatsu.reader.ui.pager.reversed.ReversedReaderFragment
 import org.koitharu.kotatsu.reader.ui.pager.standard.PagerReaderFragment
+import org.koitharu.kotatsu.reader.ui.pager.vertical.VerticalReaderFragment
 import org.koitharu.kotatsu.reader.ui.pager.webtoon.WebtoonReaderFragment
 import java.util.EnumMap
 
@@ -21,6 +22,7 @@ class ReaderManager(
 		modeMap[ReaderMode.STANDARD] = PagerReaderFragment::class.java
 		modeMap[ReaderMode.REVERSED] = ReversedReaderFragment::class.java
 		modeMap[ReaderMode.WEBTOON] = WebtoonReaderFragment::class.java
+		modeMap[ReaderMode.VERTICAL] = VerticalReaderFragment::class.java
 	}
 
 	val currentReader: BaseReaderFragment<*>?

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/config/ReaderConfigSheet.kt

@@ -79,6 +79,7 @@ class ReaderConfigSheet :
 		binding.buttonStandard.isChecked = mode == ReaderMode.STANDARD
 		binding.buttonReversed.isChecked = mode == ReaderMode.REVERSED
 		binding.buttonWebtoon.isChecked = mode == ReaderMode.WEBTOON
+		binding.buttonVertical.isChecked = mode == ReaderMode.VERTICAL
 
 		binding.checkableGroup.addOnButtonCheckedListener(this)
 		binding.buttonSavePage.setOnClickListener(this)
@@ -153,6 +154,7 @@ class ReaderConfigSheet :
 			R.id.button_standard -> ReaderMode.STANDARD
 			R.id.button_webtoon -> ReaderMode.WEBTOON
 			R.id.button_reversed -> ReaderMode.REVERSED
+			R.id.button_vertical -> ReaderMode.VERTICAL
 			else -> return
 		}
 		if (newMode == mode) {

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/vertical/VerticalPageAnimTransformer.kt

@@ -0,0 +1,31 @@
+package org.koitharu.kotatsu.reader.ui.pager.vertical
+
+import android.view.View
+import androidx.viewpager2.widget.ViewPager2
+
+class VerticalPageAnimTransformer : ViewPager2.PageTransformer {
+
+	override fun transformPage(page: View, position: Float) = with(page) {
+		translationY = -position * height
+		pivotX = width / 2f
+		pivotY = height * 0.2f
+		cameraDistance = 20000f
+		when {
+			position < -1f || position > 1f -> {
+				alpha = 0f
+				rotationX = 0f
+				translationZ = -1f
+			}
+			position > 0f -> {
+				alpha = 1f
+				rotationX = 0f
+				translationZ = 0f
+			}
+			position <= 0f -> {
+				alpha = 1f
+				rotationX = -120 * position
+				translationZ = 2f
+			}
+		}
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/vertical/VerticalReaderFragment.kt

@@ -0,0 +1,186 @@
+package org.koitharu.kotatsu.reader.ui.pager.vertical
+
+import android.os.Build
+import android.os.Bundle
+import android.view.InputDevice
+import android.view.KeyEvent
+import android.view.LayoutInflater
+import android.view.MotionEvent
+import android.view.View
+import android.view.ViewGroup
+import androidx.core.view.children
+import androidx.viewpager2.widget.ViewPager2
+import com.google.android.material.snackbar.Snackbar
+import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.yield
+import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.core.os.NetworkState
+import org.koitharu.kotatsu.core.prefs.ReaderAnimation
+import org.koitharu.kotatsu.core.ui.list.lifecycle.PagerLifecycleDispatcher
+import org.koitharu.kotatsu.core.util.ext.doOnPageChanged
+import org.koitharu.kotatsu.core.util.ext.findCurrentViewHolder
+import org.koitharu.kotatsu.core.util.ext.observe
+import org.koitharu.kotatsu.core.util.ext.recyclerView
+import org.koitharu.kotatsu.core.util.ext.resetTransformations
+import org.koitharu.kotatsu.databinding.FragmentReaderStandardBinding
+import org.koitharu.kotatsu.reader.domain.PageLoader
+import org.koitharu.kotatsu.reader.ui.ReaderState
+import org.koitharu.kotatsu.reader.ui.pager.BaseReaderAdapter
+import org.koitharu.kotatsu.reader.ui.pager.BaseReaderFragment
+import org.koitharu.kotatsu.reader.ui.pager.ReaderPage
+import org.koitharu.kotatsu.reader.ui.pager.standard.NoAnimPageTransformer
+import org.koitharu.kotatsu.reader.ui.pager.standard.PageHolder
+import org.koitharu.kotatsu.reader.ui.pager.standard.PagerEventSupplier
+import org.koitharu.kotatsu.reader.ui.pager.standard.PagesAdapter
+import javax.inject.Inject
+import kotlin.math.absoluteValue
+import kotlin.math.sign
+
+@AndroidEntryPoint
+class VerticalReaderFragment : BaseReaderFragment<FragmentReaderStandardBinding>(),
+	View.OnGenericMotionListener {
+
+	@Inject
+	lateinit var networkState: NetworkState
+
+	@Inject
+	lateinit var pageLoader: PageLoader
+
+	private var pagerLifecycleDispatcher: PagerLifecycleDispatcher? = null
+
+	override fun onCreateViewBinding(
+		inflater: LayoutInflater,
+		container: ViewGroup?,
+	) = FragmentReaderStandardBinding.inflate(inflater, container, false)
+
+	override fun onViewBindingCreated(
+		binding: FragmentReaderStandardBinding,
+		savedInstanceState: Bundle?,
+	) {
+		super.onViewBindingCreated(binding, savedInstanceState)
+		with(binding.pager) {
+			orientation = ViewPager2.ORIENTATION_VERTICAL
+			adapter = readerAdapter
+			offscreenPageLimit = 2
+			doOnPageChanged(::notifyPageChanged)
+			setOnGenericMotionListener(this@VerticalReaderFragment)
+			if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+				recyclerView?.defaultFocusHighlightEnabled = false
+			}
+			PagerEventSupplier(this).attach()
+			pagerLifecycleDispatcher = PagerLifecycleDispatcher(this).also {
+				registerOnPageChangeCallback(it)
+			}
+		}
+
+		viewModel.pageAnimation.observe(viewLifecycleOwner) {
+			val transformer = when (it) {
+				ReaderAnimation.NONE -> NoAnimPageTransformer()
+				ReaderAnimation.DEFAULT -> null
+				ReaderAnimation.ADVANCED -> VerticalPageAnimTransformer()
+			}
+			binding.pager.setPageTransformer(transformer)
+			if (transformer == null) {
+				binding.pager.recyclerView?.children?.forEach { view ->
+					view.resetTransformations()
+				}
+			}
+		}
+	}
+
+	override fun onDestroyView() {
+		pagerLifecycleDispatcher = null
+		requireViewBinding().pager.adapter = null
+		super.onDestroyView()
+	}
+
+	override fun onZoomIn() {
+		(viewBinding?.pager?.findCurrentViewHolder() as? PageHolder)?.onZoomIn()
+	}
+
+	override fun onZoomOut() {
+		(viewBinding?.pager?.findCurrentViewHolder() as? PageHolder)?.onZoomOut()
+	}
+
+	override fun onGenericMotion(v: View?, event: MotionEvent): Boolean {
+		if (event.source and InputDevice.SOURCE_CLASS_POINTER != 0) {
+			if (event.actionMasked == MotionEvent.ACTION_SCROLL) {
+				val axisValue = event.getAxisValue(MotionEvent.AXIS_VSCROLL)
+				val withCtrl = event.metaState and KeyEvent.META_CTRL_MASK != 0
+				if (!withCtrl) {
+					switchPageBy(-axisValue.sign.toInt())
+					return true
+				}
+			}
+		}
+		return false
+	}
+
+	override suspend fun onPagesChanged(pages: List<ReaderPage>, pendingState: ReaderState?) =
+		coroutineScope {
+			val items = launch {
+				requireAdapter().setItems(pages)
+				yield()
+				pagerLifecycleDispatcher?.invalidate()
+			}
+			if (pendingState != null) {
+				val position = pages.indexOfFirst {
+					it.chapterId == pendingState.chapterId && it.index == pendingState.page
+				}
+				items.join()
+				if (position != -1) {
+					requireViewBinding().pager.setCurrentItem(position, false)
+					notifyPageChanged(position)
+				} else {
+					Snackbar.make(requireView(), R.string.not_found_404, Snackbar.LENGTH_SHORT)
+						.show()
+				}
+			} else {
+				items.join()
+			}
+		}
+
+	override fun onCreateAdapter() = PagesAdapter(
+		lifecycleOwner = viewLifecycleOwner,
+		loader = pageLoader,
+		settings = viewModel.readerSettings,
+		networkState = networkState,
+		exceptionResolver = exceptionResolver,
+	)
+
+	override fun switchPageBy(delta: Int) {
+		with(requireViewBinding().pager) {
+			setCurrentItem(currentItem + delta, isAnimationEnabled())
+		}
+	}
+
+	override fun switchPageTo(position: Int, smooth: Boolean) {
+		with(requireViewBinding().pager) {
+			setCurrentItem(
+				position,
+				smooth && isAnimationEnabled() && (currentItem - position).absoluteValue < SMOOTH_SCROLL_LIMIT,
+			)
+		}
+	}
+
+	override fun getCurrentState(): ReaderState? = viewBinding?.run {
+		val adapter = pager.adapter as? BaseReaderAdapter<*>
+		val page = adapter?.getItemOrNull(pager.currentItem) ?: return@run null
+		ReaderState(
+			chapterId = page.chapterId,
+			page = page.index,
+			scroll = 0,
+		)
+	}
+
+	private fun notifyPageChanged(page: Int) {
+		viewModel.onCurrentPageChanged(page)
+	}
+
+	companion object {
+
+		const val SMOOTH_SCROLL_LIMIT = 3
+	}
+}

app/src/main/res/drawable/ic_reader_vertical.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:width="24dp"
+	android:height="24dp"
+	android:tint="?attr/colorControlNormal"
+	android:viewportWidth="24"
+	android:viewportHeight="24">
+	<path
+		android:fillColor="#000"
+		android:pathData="M18 2H6C4.89 2 4 2.9 4 4V20C4 21.11 4.89 22 6 22H18C19.11 22 20 21.11 20 20V4C20 2.9 19.11 2 18 2M18 20H6V16H18V20M18 8H6V4H18V8Z" />
+</vector>

app/src/main/res/layout/sheet_reader_config.xml

@@ -101,6 +101,15 @@
 					android:text="@string/right_to_left"
 					app:icon="@drawable/ic_reader_rtl" />
 
+				<com.google.android.material.button.MaterialButton
+					android:id="@+id/button_vertical"
+					style="@style/Widget.Kotatsu.ToggleButton.Vertical"
+					android:layout_width="0dp"
+					android:layout_height="wrap_content"
+					android:layout_weight="1"
+					android:text="@string/vertical"
+					app:icon="@drawable/ic_reader_vertical" />
+
 				<com.google.android.material.button.MaterialButton
 					android:id="@+id/button_webtoon"
 					style="@style/Widget.Kotatsu.ToggleButton.Vertical"

app/src/main/res/values/strings.xml

@@ -565,4 +565,5 @@
 	<string name="volume_">Volume %d</string>
 	<string name="volume_unknown">Unknown volume</string>
 	<string name="incognito_mode_hint">Your reading progress will not be saved</string>
+	<string name="vertical">Vertical</string>
 </resources>