Smooth auto scrolling #319

app/src/main/java/org/koitharu/kotatsu/reader/ui/ReaderActivity.kt

@@ -40,7 +40,6 @@ import org.koitharu.kotatsu.databinding.ActivityReaderBinding
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaChapter
 import org.koitharu.kotatsu.parsers.model.MangaPage
-import org.koitharu.kotatsu.reader.ui.config.PageSwitchTimer
 import org.koitharu.kotatsu.reader.ui.config.ReaderConfigBottomSheet
 import org.koitharu.kotatsu.reader.ui.pager.ReaderUiState
 import org.koitharu.kotatsu.reader.ui.thumbnails.OnPageSelectListener
@@ -70,16 +69,16 @@ class ReaderActivity :
 
 	private val viewModel: ReaderViewModel by viewModels()
 
-	override var pageSwitchDelay: Float
-		get() = pageSwitchTimer.delaySec
+	override var autoScrollSpeed: Float
+		get() = scrollTimer.speed
 		set(value) {
-			pageSwitchTimer.delaySec = value
+			scrollTimer.speed = value
 		}
 
 	override val readerMode: ReaderMode?
 		get() = readerManager.currentMode
 
-	private lateinit var pageSwitchTimer: PageSwitchTimer
+	private lateinit var scrollTimer: ScrollTimer
 	private lateinit var touchHelper: GridTouchHelper
 	private lateinit var controlDelegate: ReaderControlDelegate
 	private var gestureInsets: Insets = Insets.NONE
@@ -92,7 +91,7 @@ class ReaderActivity :
 		readerManager = ReaderManager(supportFragmentManager, R.id.container)
 		supportActionBar?.setDisplayHomeAsUpEnabled(true)
 		touchHelper = GridTouchHelper(this, this)
-		pageSwitchTimer = PageSwitchTimer(this, this)
+		scrollTimer = ScrollTimer(this, this)
 		controlDelegate = ReaderControlDelegate(settings, this, this)
 		binding.toolbarBottom.setOnMenuItemClickListener(::onOptionsItemSelected)
 		binding.slider.setLabelFormatter(PageLabelFormatter())
@@ -134,7 +133,6 @@ class ReaderActivity :
 
 	override fun onUserInteraction() {
 		super.onUserInteraction()
-		pageSwitchTimer.onUserInteraction()
 		idlingDetector.onUserInteraction()
 	}
 
@@ -337,6 +335,10 @@ class ReaderActivity :
 		readerManager.currentReader?.switchPageBy(delta)
 	}
 
+	override fun scrollBy(delta: Int): Boolean {
+		return readerManager.currentReader?.scrollBy(delta) ?: false
+	}
+
 	override fun toggleUiVisibility() {
 		setUiIsVisible(!binding.appbarTop.isVisible)
 	}

app/src/main/java/org/koitharu/kotatsu/reader/ui/ReaderControlDelegate.kt

@@ -42,18 +42,22 @@ class ReaderControlDelegate(
 				listener.toggleUiVisibility()
 				view.playSoundEffect(SoundEffectConstants.CLICK)
 			}
+
 			GridTouchHelper.AREA_TOP -> if (isTapSwitchEnabled) {
 				listener.switchPageBy(-1)
 				view.playSoundEffect(SoundEffectConstants.NAVIGATION_UP)
 			}
+
 			GridTouchHelper.AREA_LEFT -> if (isTapSwitchEnabled) {
 				listener.switchPageBy(if (isReaderTapsReversed()) 1 else -1)
 				view.playSoundEffect(SoundEffectConstants.NAVIGATION_LEFT)
 			}
+
 			GridTouchHelper.AREA_BOTTOM -> if (isTapSwitchEnabled) {
 				listener.switchPageBy(1)
 				view.playSoundEffect(SoundEffectConstants.NAVIGATION_DOWN)
 			}
+
 			GridTouchHelper.AREA_RIGHT -> if (isTapSwitchEnabled) {
 				listener.switchPageBy(if (isReaderTapsReversed()) -1 else 1)
 				view.playSoundEffect(SoundEffectConstants.NAVIGATION_RIGHT)
@@ -68,12 +72,14 @@ class ReaderControlDelegate(
 		} else {
 			false
 		}
+
 		KeyEvent.KEYCODE_VOLUME_DOWN -> if (isVolumeKeysSwitchEnabled) {
 			listener.switchPageBy(1)
 			true
 		} else {
 			false
 		}
+
 		KeyEvent.KEYCODE_SPACE,
 		KeyEvent.KEYCODE_PAGE_DOWN,
 		KeyEvent.KEYCODE_SYSTEM_NAVIGATION_DOWN,
@@ -82,10 +88,12 @@ class ReaderControlDelegate(
 			listener.switchPageBy(1)
 			true
 		}
+
 		KeyEvent.KEYCODE_DPAD_RIGHT -> {
 			listener.switchPageBy(if (isReaderTapsReversed()) -1 else 1)
 			true
 		}
+
 		KeyEvent.KEYCODE_PAGE_UP,
 		KeyEvent.KEYCODE_SYSTEM_NAVIGATION_UP,
 		KeyEvent.KEYCODE_DPAD_UP,
@@ -93,14 +101,17 @@ class ReaderControlDelegate(
 			listener.switchPageBy(-1)
 			true
 		}
+
 		KeyEvent.KEYCODE_DPAD_LEFT -> {
 			listener.switchPageBy(if (isReaderTapsReversed()) 1 else -1)
 			true
 		}
+
 		KeyEvent.KEYCODE_DPAD_CENTER -> {
 			listener.toggleUiVisibility()
 			true
 		}
+
 		else -> false
 	}
 
@@ -128,6 +139,8 @@ class ReaderControlDelegate(
 
 		fun switchPageBy(delta: Int)
 
+		fun scrollBy(delta: Int): Boolean
+
 		fun toggleUiVisibility()
 	}
 }

app/src/main/java/org/koitharu/kotatsu/reader/ui/ScrollTimer.kt

@@ -0,0 +1,72 @@
+package org.koitharu.kotatsu.reader.ui
+
+import androidx.annotation.FloatRange
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.coroutineScope
+import androidx.lifecycle.repeatOnLifecycle
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlin.math.roundToLong
+
+private const val MIN_SPEED = 0.1
+private const val MAX_DELAY = 80L
+private const val MAX_SWITCH_DELAY = 20_000L
+
+class ScrollTimer(
+	private val lifecycleOwner: LifecycleOwner,
+	private val listener: ReaderControlDelegate.OnInteractionListener,
+) {
+
+	private var job: Job? = null
+	private var delayMs: Long = 10L
+	private var pageSwitchDelay: Long = 100L
+
+	@FloatRange(from = 0.0, to = 1.0)
+	var speed: Float = 0f
+		set(value) {
+			if (field != value) {
+				field = value
+				onSpeedChanged()
+			}
+		}
+
+	private fun onSpeedChanged() {
+		if (speed < MIN_SPEED) {
+			delayMs = 0L
+			pageSwitchDelay = 0L
+		} else {
+			val speedFactor = 1 - speed + MIN_SPEED
+			delayMs = (MAX_DELAY * speedFactor).roundToLong()
+			pageSwitchDelay = (MAX_SWITCH_DELAY * speedFactor).roundToLong()
+		}
+		if ((job == null) != (delayMs == 0L)) {
+			restartJob()
+		}
+	}
+
+	private fun restartJob() {
+		job?.cancel()
+		if (delayMs == 0L) {
+			job = null
+			return
+		}
+		job = lifecycleOwner.lifecycle.coroutineScope.launch {
+			lifecycleOwner.repeatOnLifecycle(Lifecycle.State.RESUMED) {
+				var accumulator = 0L
+				while (isActive) {
+					delay(delayMs)
+					if (!listener.scrollBy(1)) {
+						accumulator += delayMs
+					}
+					if (accumulator >= pageSwitchDelay) {
+						listener.switchPageBy(1)
+						accumulator -= pageSwitchDelay
+					}
+				}
+			}
+		}
+	}
+}

app/src/main/java/org/koitharu/kotatsu/reader/ui/config/PageSwitchTimer.kt

@@ -6,7 +6,6 @@ import androidx.lifecycle.LifecycleOwner
 import androidx.lifecycle.coroutineScope
 import androidx.lifecycle.repeatOnLifecycle
 import com.google.android.material.slider.LabelFormatter
-import kotlin.math.roundToLong
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.isActive
@@ -14,7 +13,9 @@ import kotlinx.coroutines.launch
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.parsers.util.format
 import org.koitharu.kotatsu.reader.ui.ReaderControlDelegate
+import kotlin.math.roundToLong
 
+@Deprecated("")
 class PageSwitchTimer(
 	private val listener: ReaderControlDelegate.OnInteractionListener,
 	private val lifecycleOwner: LifecycleOwner,

app/src/main/java/org/koitharu/kotatsu/reader/ui/config/ReaderConfigBottomSheet.kt

@@ -6,6 +6,7 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.activity.result.ActivityResultCallback
+import androidx.annotation.FloatRange
 import androidx.core.view.isGone
 import androidx.fragment.app.FragmentManager
 import androidx.fragment.app.activityViewModels
@@ -23,7 +24,6 @@ import org.koitharu.kotatsu.reader.ui.ReaderViewModel
 import org.koitharu.kotatsu.reader.ui.colorfilter.ColorFilterConfigActivity
 import org.koitharu.kotatsu.settings.SettingsActivity
 import org.koitharu.kotatsu.utils.ScreenOrientationHelper
-import org.koitharu.kotatsu.utils.ext.setValueRounded
 import org.koitharu.kotatsu.utils.ext.viewLifecycleScope
 import org.koitharu.kotatsu.utils.ext.withArgs
 
@@ -32,7 +32,7 @@ class ReaderConfigBottomSheet :
 	ActivityResultCallback<Uri?>,
 	View.OnClickListener,
 	MaterialButtonToggleGroup.OnButtonCheckedListener,
-	Slider.OnSliderTouchListener {
+	Slider.OnChangeListener {
 
 	private val viewModel by activityViewModels<ReaderViewModel>()
 	private val savePageRequest = registerForActivityResult(PageSaveContract(), this)
@@ -62,11 +62,10 @@ class ReaderConfigBottomSheet :
 		binding.buttonScreenRotate.setOnClickListener(this)
 		binding.buttonSettings.setOnClickListener(this)
 		binding.buttonColorFilter.setOnClickListener(this)
-		binding.sliderTimer.addOnSliderTouchListener(this)
-		binding.sliderTimer.setLabelFormatter(PageSwitchTimer.DelayLabelFormatter(view.resources))
+		binding.sliderTimer.addOnChangeListener(this)
 
 		findCallback()?.run {
-			binding.sliderTimer.setValueRounded(pageSwitchDelay)
+			binding.sliderTimer.value = autoScrollSpeed
 		}
 	}
 
@@ -111,10 +110,8 @@ class ReaderConfigBottomSheet :
 		mode = newMode
 	}
 
-	override fun onStartTrackingTouch(slider: Slider) = Unit
-
-	override fun onStopTrackingTouch(slider: Slider) {
-		findCallback()?.pageSwitchDelay = slider.value
+	override fun onValueChange(slider: Slider, value: Float, fromUser: Boolean) {
+		findCallback()?.autoScrollSpeed = value
 	}
 
 	override fun onActivityResult(uri: Uri?) {
@@ -138,7 +135,8 @@ class ReaderConfigBottomSheet :
 
 	interface Callback {
 
-		var pageSwitchDelay: Float
+		@get:FloatRange(from = 0.0, to = 1.0)
+		var autoScrollSpeed: Float
 
 		fun onReaderModeChanged(mode: ReaderMode)
 	}

app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/BaseReader.kt

@@ -51,6 +51,8 @@ abstract class BaseReader<B : ViewBinding> : BaseFragment<B>() {
 
 	abstract fun switchPageTo(position: Int, smooth: Boolean)
 
+	open fun scrollBy(delta: Int): Boolean = false
+
 	abstract fun getCurrentState(): ReaderState?
 
 	protected abstract fun onPagesChanged(pages: List<ReaderPage>, pendingState: ReaderState?)

app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/webtoon/WebtoonReaderFragment.kt

@@ -114,6 +114,11 @@ class WebtoonReaderFragment : BaseReader<FragmentReaderWebtoonBinding>() {
 		binding.recyclerView.firstVisibleItemPosition = position
 	}
 
+	override fun scrollBy(delta: Int): Boolean {
+		binding.recyclerView.nestedScrollBy(0, delta)
+		return true
+	}
+
 	private inner class PageScrollListener : WebtoonRecyclerView.OnPageScrollListener() {
 
 		override fun onPageChanged(recyclerView: WebtoonRecyclerView, index: Int) {

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

@@ -139,7 +139,7 @@
 					android:contentDescription="@string/automatic_scroll"
 					android:labelFor="@id/textView_timer"
 					android:valueFrom="0"
-					android:valueTo="20"
+					android:valueTo="1"
 					app:labelBehavior="floating"
 					app:layout_constraintBottom_toBottomOf="parent"
 					app:layout_constraintEnd_toEndOf="parent"