Improve keyboard control in reader

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

@@ -107,7 +107,7 @@ class ReaderActivity :
 		supportActionBar?.setDisplayHomeAsUpEnabled(true)
 		touchHelper = GridTouchHelper(this, this)
 		scrollTimer = scrollTimerFactory.create(this, this)
-		controlDelegate = ReaderControlDelegate(settings, this, this)
+		controlDelegate = ReaderControlDelegate(resources, settings, this, this)
 		viewBinding.toolbarBottom.setOnMenuItemClickListener(::onOptionsItemSelected)
 		viewBinding.slider.setLabelFormatter(PageLabelFormatter())
 		ReaderSliderListener(this, viewModel).attachToSlider(viewBinding.slider)
@@ -347,8 +347,8 @@ class ReaderActivity :
 		readerManager.currentReader?.switchPageBy(delta)
 	}
 
-	override fun scrollBy(delta: Int): Boolean {
-		return readerManager.currentReader?.scrollBy(delta) ?: false
+	override fun scrollBy(delta: Int, smooth: Boolean): Boolean {
+		return readerManager.currentReader?.scrollBy(delta, smooth) ?: false
 	}
 
 	override fun toggleUiVisibility() {

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

@@ -1,16 +1,19 @@
 package org.koitharu.kotatsu.reader.ui
 
 import android.content.SharedPreferences
+import android.content.res.Resources
 import android.view.KeyEvent
 import android.view.SoundEffectConstants
 import android.view.View
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
+import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.core.util.GridTouchHelper
 
 class ReaderControlDelegate(
+	resources: Resources,
 	private val settings: AppSettings,
 	private val listener: OnInteractionListener,
 	owner: LifecycleOwner,
@@ -19,6 +22,7 @@ class ReaderControlDelegate(
 	private var isTapSwitchEnabled: Boolean = true
 	private var isVolumeKeysSwitchEnabled: Boolean = false
 	private var isReaderTapsAdaptive: Boolean = true
+	private var minScrollDelta = resources.getDimensionPixelSize(R.dimen.reader_scroll_delta_min)
 
 	init {
 		owner.lifecycle.addObserver(this)
@@ -82,8 +86,6 @@ class ReaderControlDelegate(
 
 		KeyEvent.KEYCODE_SPACE,
 		KeyEvent.KEYCODE_PAGE_DOWN,
-		KeyEvent.KEYCODE_SYSTEM_NAVIGATION_DOWN,
-		KeyEvent.KEYCODE_DPAD_DOWN,
 		-> {
 			listener.switchPageBy(1)
 			true
@@ -95,8 +97,6 @@ class ReaderControlDelegate(
 		}
 
 		KeyEvent.KEYCODE_PAGE_UP,
-		KeyEvent.KEYCODE_SYSTEM_NAVIGATION_UP,
-		KeyEvent.KEYCODE_DPAD_UP,
 		-> {
 			listener.switchPageBy(-1)
 			true
@@ -112,6 +112,22 @@ class ReaderControlDelegate(
 			true
 		}
 
+		KeyEvent.KEYCODE_SYSTEM_NAVIGATION_UP,
+		KeyEvent.KEYCODE_DPAD_UP -> {
+			if (!listener.scrollBy(-minScrollDelta, smooth = true)) {
+				listener.switchPageBy(-1)
+			}
+			true
+		}
+
+		KeyEvent.KEYCODE_SYSTEM_NAVIGATION_DOWN,
+		KeyEvent.KEYCODE_DPAD_DOWN -> {
+			if (!listener.scrollBy(minScrollDelta, smooth = true)) {
+				listener.switchPageBy(1)
+			}
+			true
+		}
+
 		else -> false
 	}
 
@@ -139,7 +155,7 @@ class ReaderControlDelegate(
 
 		fun switchPageBy(delta: Int)
 
-		fun scrollBy(delta: Int): Boolean
+		fun scrollBy(delta: Int, smooth: Boolean): Boolean
 
 		fun toggleUiVisibility()
 

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

@@ -96,7 +96,7 @@ class ScrollTimer @AssistedInject constructor(
 				if (!listener.isReaderResumed()) {
 					continue
 				}
-				if (!listener.scrollBy(1)) {
+				if (!listener.scrollBy(1, false)) {
 					accumulator += delayMs
 				}
 				if (accumulator >= pageSwitchDelay) {

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

@@ -66,7 +66,7 @@ abstract class BaseReaderFragment<B : ViewBinding> : BaseFragment<B>() {
 
 	abstract fun switchPageTo(position: Int, smooth: Boolean)
 
-	open fun scrollBy(delta: Int): Boolean = false
+	open fun scrollBy(delta: Int, smooth: Boolean): Boolean = false
 
 	abstract fun getCurrentState(): ReaderState?
 

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/reversed/ReversedReaderFragment.kt

@@ -1,5 +1,6 @@
 package org.koitharu.kotatsu.reader.ui.pager.reversed
 
+import android.os.Build
 import android.os.Bundle
 import android.view.InputDevice
 import android.view.KeyEvent
@@ -27,6 +28,7 @@ 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.PagerEventSupplier
 import org.koitharu.kotatsu.reader.ui.pager.standard.PagerReaderFragment
 import javax.inject.Inject
 import kotlin.math.absoluteValue
@@ -54,6 +56,10 @@ class ReversedReaderFragment : BaseReaderFragment<FragmentReaderStandardBinding>
 			offscreenPageLimit = 2
 			doOnPageChanged(::notifyPageChanged)
 			setOnGenericMotionListener(this@ReversedReaderFragment)
+			if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+				recyclerView?.defaultFocusHighlightEnabled = false
+			}
+			PagerEventSupplier(this).attach()
 		}
 
 		viewModel.pageAnimation.observe(viewLifecycleOwner) {

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/standard/PageHolder.kt

@@ -35,7 +35,6 @@ open class PageHolder(
 		binding.ssiv.bindToLifecycle(owner)
 		binding.ssiv.isEagerLoadingEnabled = !context.isLowRamDevice()
 		binding.ssiv.addOnImageEventListener(delegate)
-		binding.ssiv.setOnGenericMotionListener(SsivZoomListener())
 		@Suppress("LeakingThis")
 		bindingInfo.buttonRetry.setOnClickListener(this)
 		@Suppress("LeakingThis")

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/standard/PagerEventSupplier.kt

@@ -0,0 +1,24 @@
+package org.koitharu.kotatsu.reader.ui.pager.standard
+
+import android.view.KeyEvent
+import android.view.View
+import android.view.ViewGroup
+import androidx.core.view.children
+import androidx.viewpager2.widget.ViewPager2
+import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
+import org.koitharu.kotatsu.core.util.ext.recyclerView
+
+class PagerEventSupplier(private val pager: ViewPager2) : View.OnKeyListener {
+
+	fun attach() {
+		pager.recyclerView?.setOnKeyListener(this)
+	}
+
+	override fun onKey(v: View?, keyCode: Int, event: KeyEvent?): Boolean {
+		val rootView = pager.recyclerView?.findViewHolderForAdapterPosition(pager.currentItem)?.itemView as? ViewGroup
+			?: return false
+		return rootView.children.firstNotNullOfOrNull { x ->
+			x as? SubsamplingScaleImageView
+		}?.dispatchKeyEvent(event) == true
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/standard/PagerReaderFragment.kt

@@ -1,5 +1,6 @@
 package org.koitharu.kotatsu.reader.ui.pager.standard
 
+import android.os.Build
 import android.os.Bundle
 import android.view.InputDevice
 import android.view.KeyEvent
@@ -55,6 +56,10 @@ class PagerReaderFragment : BaseReaderFragment<FragmentReaderStandardBinding>(),
 			offscreenPageLimit = 2
 			doOnPageChanged(::notifyPageChanged)
 			setOnGenericMotionListener(this@PagerReaderFragment)
+			if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+				recyclerView?.defaultFocusHighlightEnabled = false
+			}
+			PagerEventSupplier(this).attach()
 		}
 
 		viewModel.pageAnimation.observe(viewLifecycleOwner) {

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/standard/SsivZoomListener.kt

@@ -1,32 +0,0 @@
-package org.koitharu.kotatsu.reader.ui.pager.standard
-
-import android.graphics.PointF
-import android.view.InputDevice
-import android.view.KeyEvent
-import android.view.MotionEvent
-import android.view.View
-import android.view.View.OnGenericMotionListener
-import android.view.animation.DecelerateInterpolator
-import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
-
-class SsivZoomListener : OnGenericMotionListener {
-
-	override fun onGenericMotion(v: View?, event: MotionEvent): Boolean {
-		val ssiv = v as? SubsamplingScaleImageView ?: return false
-		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 || ssiv.scale > ssiv.minScale) {
-					val center = PointF(event.x, event.y)
-					val scale = ssiv.scale + axisValue * 1.6f
-					(ssiv.animateScaleAndCenter(scale, center) ?: return false)
-						.withInterpolator(DecelerateInterpolator())
-						.start()
-					return true
-				}
-			}
-		}
-		return false
-	}
-}

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/webtoon/WebtoonFrameLayout.kt

@@ -12,8 +12,8 @@ class WebtoonFrameLayout @JvmOverloads constructor(
 	@AttrRes defStyleAttr: Int = 0,
 ) : FrameLayout(context, attrs, defStyleAttr) {
 
-	val target by lazy(LazyThreadSafetyMode.NONE) {
-		findViewById<WebtoonImageView>(R.id.ssiv)
+	val target: WebtoonImageView by lazy(LazyThreadSafetyMode.NONE) {
+		findViewById(R.id.ssiv)
 	}
 
 	fun dispatchVerticalScroll(dy: Int): Int {

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

@@ -3,7 +3,7 @@ package org.koitharu.kotatsu.reader.ui.pager.webtoon
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.ViewGroup
-import android.view.animation.AccelerateDecelerateInterpolator
+import android.view.animation.DecelerateInterpolator
 import com.google.android.material.snackbar.Snackbar
 import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.async
@@ -31,7 +31,7 @@ class WebtoonReaderFragment : BaseReaderFragment<FragmentReaderWebtoonBinding>()
 	@Inject
 	lateinit var pageLoader: PageLoader
 
-	private val scrollInterpolator = AccelerateDecelerateInterpolator()
+	private val scrollInterpolator = DecelerateInterpolator()
 
 	override fun onCreateViewBinding(
 		inflater: LayoutInflater,
@@ -122,8 +122,12 @@ class WebtoonReaderFragment : BaseReaderFragment<FragmentReaderWebtoonBinding>()
 		requireViewBinding().recyclerView.firstVisibleItemPosition = position
 	}
 
-	override fun scrollBy(delta: Int): Boolean {
-		requireViewBinding().recyclerView.nestedScrollBy(0, delta)
+	override fun scrollBy(delta: Int, smooth: Boolean): Boolean {
+		if (smooth && isAnimationEnabled()) {
+			requireViewBinding().recyclerView.smoothScrollBy(0, delta, scrollInterpolator)
+		} else {
+			requireViewBinding().recyclerView.nestedScrollBy(0, delta)
+		}
 		return true
 	}
 

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/pager/webtoon/WebtoonScalingFrame.kt

@@ -11,14 +11,17 @@ import android.view.InputDevice
 import android.view.KeyEvent
 import android.view.MotionEvent
 import android.view.ScaleGestureDetector
+import android.view.ViewConfiguration
 import android.view.animation.AccelerateDecelerateInterpolator
+import android.view.animation.DecelerateInterpolator
 import android.widget.FrameLayout
 import android.widget.OverScroller
 import androidx.core.view.GestureDetectorCompat
+import androidx.core.view.ViewConfigurationCompat
+import org.koitharu.kotatsu.core.util.ext.getAnimationDuration
 
 private const val MAX_SCALE = 2.5f
 private const val MIN_SCALE = 0.5f
-private const val WHEEL_SCALE_FACTOR = 0.2f
 
 class WebtoonScalingFrame @JvmOverloads constructor(
 	context: Context,
@@ -43,6 +46,7 @@ class WebtoonScalingFrame @JvmOverloads constructor(
 	private var halfHeight = 0f
 	private val translateBounds = RectF()
 	private val targetHitRect = Rect()
+	private var animator: ValueAnimator? = null
 
 	var isZoomEnable = true
 		set(value) {
@@ -81,13 +85,15 @@ class WebtoonScalingFrame @JvmOverloads constructor(
 	}
 
 	override fun onGenericMotionEvent(event: MotionEvent): Boolean {
-		if (event.source and InputDevice.SOURCE_CLASS_POINTER != 0) {
+		if (isZoomEnable && event.source and InputDevice.SOURCE_CLASS_POINTER != 0) {
 			if (event.actionMasked == MotionEvent.ACTION_SCROLL) {
 				val withCtrl = event.metaState and KeyEvent.META_CTRL_MASK != 0
 				if (withCtrl) {
-					val axisValue = event.getAxisValue(MotionEvent.AXIS_VSCROLL)
-					val newScale =
-						(scale + axisValue * WHEEL_SCALE_FACTOR).coerceIn(MIN_SCALE, MAX_SCALE)
+					val axisValue =
+						event.getAxisValue(MotionEvent.AXIS_VSCROLL) * ViewConfigurationCompat.getScaledVerticalScrollFactor(
+							ViewConfiguration.get(context), context,
+						)
+					val newScale = (scale + axisValue).coerceIn(MIN_SCALE, MAX_SCALE)
 					scaleChild(newScale, event.x, event.y)
 					return true
 				}
@@ -96,6 +102,49 @@ class WebtoonScalingFrame @JvmOverloads constructor(
 		return super.onGenericMotionEvent(event)
 	}
 
+	override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
+		if (!isZoomEnable) {
+			return super.onKeyDown(keyCode, event)
+		}
+		return when (keyCode) {
+			KeyEvent.KEYCODE_ZOOM_IN,
+			KeyEvent.KEYCODE_NUMPAD_ADD,
+			KeyEvent.KEYCODE_PLUS -> {
+				smoothScaleTo(scale * 1.1f)
+				true
+			}
+
+			KeyEvent.KEYCODE_ZOOM_OUT,
+			KeyEvent.KEYCODE_NUMPAD_SUBTRACT,
+			KeyEvent.KEYCODE_MINUS -> {
+				smoothScaleTo(scale * 0.9f)
+				true
+			}
+
+			KeyEvent.KEYCODE_ESCAPE -> {
+				smoothScaleTo(1f)
+				true
+			}
+
+			else -> super.onKeyDown(keyCode, event)
+		}
+	}
+
+	override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
+		return if (isZoomEnable) {
+			keyCode == KeyEvent.KEYCODE_NUMPAD_ADD
+				|| keyCode == KeyEvent.KEYCODE_PLUS
+				|| keyCode == KeyEvent.KEYCODE_NUMPAD_SUBTRACT
+				|| keyCode == KeyEvent.KEYCODE_MINUS
+				|| keyCode == KeyEvent.KEYCODE_ZOOM_IN
+				|| keyCode == KeyEvent.KEYCODE_ZOOM_OUT
+				|| keyCode == KeyEvent.KEYCODE_ESCAPE
+				|| super.onKeyUp(keyCode, event)
+		} else {
+			super.onKeyUp(keyCode, event)
+		}
+	}
+
 	override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
 		super.onSizeChanged(w, h, oldw, oldh)
 		halfWidth = w / 2f
@@ -173,10 +222,24 @@ class WebtoonScalingFrame @JvmOverloads constructor(
 		return true
 	}
 
-	override fun onScaleBegin(detector: ScaleGestureDetector): Boolean = true
+	override fun onScaleBegin(detector: ScaleGestureDetector): Boolean {
+		animator?.cancel()
+		animator = null
+		return true
+	}
 
 	override fun onScaleEnd(p0: ScaleGestureDetector) = Unit
 
+	private fun smoothScaleTo(target: Float) {
+		val newScale = target.coerceIn(MIN_SCALE, MAX_SCALE)
+		animator?.cancel()
+		animator = ValueAnimator.ofFloat(scale, newScale).apply {
+			setDuration(context.getAnimationDuration(android.R.integer.config_shortAnimTime))
+			interpolator = DecelerateInterpolator()
+			addUpdateListener { scaleChild(it.animatedValue as Float, halfWidth, halfHeight) }
+			start()
+		}
+	}
 
 	private inner class GestureListener : GestureDetector.SimpleOnGestureListener(), Runnable {
 
@@ -231,7 +294,7 @@ class WebtoonScalingFrame @JvmOverloads constructor(
 			if (overScroller.computeScrollOffset()) {
 				transformMatrix.postTranslate(
 					overScroller.currX - transX,
-					overScroller.currY - transY
+					overScroller.currY - transY,
 				)
 				invalidateTarget()
 				postOnAnimation(this)

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

@@ -3,4 +3,5 @@
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	android:id="@+id/pager"
 	android:layout_width="match_parent"
-	android:layout_height="match_parent" />
+	android:layout_height="match_parent"
+	android:defaultFocusHighlightEnabled="false" />

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

@@ -4,12 +4,15 @@
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	android:id="@+id/frame"
 	android:layout_width="match_parent"
-	android:layout_height="match_parent">
+	android:layout_height="match_parent"
+	android:focusable="true"
+	android:defaultFocusHighlightEnabled="false">
 
 	<org.koitharu.kotatsu.reader.ui.pager.webtoon.WebtoonRecyclerView
 		android:id="@+id/recyclerView"
 		android:layout_width="match_parent"
 		android:layout_height="match_parent"
+		android:defaultFocusHighlightEnabled="false"
 		android:orientation="vertical"
 		app:layoutManager="org.koitharu.kotatsu.reader.ui.pager.webtoon.WebtoonLayoutManager" />
 </org.koitharu.kotatsu.reader.ui.pager.webtoon.WebtoonScalingFrame>

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

@@ -10,6 +10,8 @@
 		android:id="@+id/ssiv"
 		android:layout_width="match_parent"
 		android:layout_height="match_parent"
+		android:defaultFocusHighlightEnabled="false"
+		android:focusable="true"
 		app:restoreStrategy="deferred" />
 
 	<TextView

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

@@ -3,12 +3,14 @@
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	android:layout_width="match_parent"
-	android:layout_height="wrap_content">
+	android:layout_height="wrap_content"
+	android:defaultFocusHighlightEnabled="false">
 
 	<org.koitharu.kotatsu.reader.ui.pager.webtoon.WebtoonImageView
 		android:id="@+id/ssiv"
 		android:layout_width="match_parent"
 		android:layout_height="wrap_content"
+		android:defaultFocusHighlightEnabled="false"
 		android:minHeight="1dp"
 		app:panEnabled="false"
 		app:quickScaleEnabled="false"

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

@@ -80,4 +80,6 @@
 	<dimen name="fastscroll_scrollbar_padding_end">6dp</dimen>
 
 	<dimen name="m3_side_sheet_width">400dp</dimen>
+
+	<dimen name="reader_scroll_delta_min">200dp</dimen>
 </resources>