Scale mode option for reader

app/build.gradle

@@ -16,7 +16,7 @@ android {
 		minSdkVersion 21
 		targetSdkVersion 30
 		versionCode gitCommits
-		versionName '0.5.4'
+		versionName '1.0-a1'
 
 		kapt {
 			arguments {
@@ -63,8 +63,8 @@ tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
 dependencies {
 	implementation fileTree(dir: 'libs', include: ['*.jar', '*.aar'])
 	implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
-	implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.0'
+	implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.1'
-	implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.4.0'
+	implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.4.1'
 
 	implementation 'androidx.core:core-ktx:1.5.0-alpha04'
 	implementation 'androidx.activity:activity-ktx:1.2.0-beta01'

app/src/main/java/org/koitharu/kotatsu/core/model/ZoomMode.kt

@@ -0,0 +1,6 @@
+package org.koitharu.kotatsu.core.model
+
+enum class ZoomMode {
+
+	FIT_CENTER, FIT_HEIGHT, FIT_WIDTH, KEEP_START
+}

app/src/main/java/org/koitharu/kotatsu/core/parser/RemoteMangaRepository.kt

@@ -6,11 +6,13 @@ import org.koitharu.kotatsu.core.model.MangaTag
 import org.koitharu.kotatsu.core.model.SortOrder
 import org.koitharu.kotatsu.domain.MangaLoaderContext
 
-abstract class RemoteMangaRepository(protected val loaderContext: MangaLoaderContext) : MangaRepository {
+abstract class RemoteMangaRepository(
+	protected val loaderContext: MangaLoaderContext
+) : MangaRepository {
 
 	protected abstract val source: MangaSource
 
-	protected val conf by lazy(LazyThreadSafetyMode.NONE) {
+	protected val conf by lazy {
 		loaderContext.getSettings(source)
 	}
 

app/src/main/java/org/koitharu/kotatsu/core/parser/site/ChanRepository.kt

@@ -7,6 +7,7 @@ import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.core.prefs.SourceSettings
 import org.koitharu.kotatsu.domain.MangaLoaderContext
 import org.koitharu.kotatsu.utils.ext.*
+import java.util.*
 
 abstract class ChanRepository(loaderContext: MangaLoaderContext) : RemoteMangaRepository(
 	loaderContext
@@ -14,7 +15,7 @@ abstract class ChanRepository(loaderContext: MangaLoaderContext) : RemoteMangaRe
 
 	protected abstract val defaultDomain: String
 
-	override val sortOrders = arraySetOf(
+	override val sortOrders: Set<SortOrder> = EnumSet.of(
 		SortOrder.NEWEST,
 		SortOrder.POPULARITY,
 		SortOrder.ALPHABETICAL

app/src/main/java/org/koitharu/kotatsu/core/parser/site/DesuMeRepository.kt

@@ -7,12 +7,14 @@ import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.core.prefs.SourceSettings
 import org.koitharu.kotatsu.domain.MangaLoaderContext
 import org.koitharu.kotatsu.utils.ext.*
+import java.util.*
+import kotlin.collections.ArrayList
 
 class DesuMeRepository(loaderContext: MangaLoaderContext) : RemoteMangaRepository(loaderContext) {
 
 	override val source = MangaSource.DESUME
 
-	override val sortOrders = arraySetOf(
+	override val sortOrders: Set<SortOrder> = EnumSet.of(
 		SortOrder.UPDATED,
 		SortOrder.POPULARITY,
 		SortOrder.NEWEST,

app/src/main/java/org/koitharu/kotatsu/core/parser/site/GroupleRepository.kt

@@ -7,13 +7,14 @@ import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.core.prefs.SourceSettings
 import org.koitharu.kotatsu.domain.MangaLoaderContext
 import org.koitharu.kotatsu.utils.ext.*
+import java.util.*
 
 abstract class GroupleRepository(loaderContext: MangaLoaderContext) :
 	RemoteMangaRepository(loaderContext) {
 
 	protected abstract val defaultDomain: String
 
-	override val sortOrders = arraySetOf(
+	override val sortOrders: Set<SortOrder> = EnumSet.of(
 		SortOrder.UPDATED, SortOrder.POPULARITY,
 		SortOrder.NEWEST, SortOrder.RATING
 		//FIXME SortOrder.ALPHABETICAL

app/src/main/java/org/koitharu/kotatsu/core/parser/site/MangaLibRepository.kt

@@ -4,13 +4,14 @@ import androidx.collection.ArraySet
 import androidx.collection.arraySetOf
 import org.json.JSONArray
 import org.json.JSONObject
-import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.exceptions.ParseException
 import org.koitharu.kotatsu.core.model.*
 import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.core.prefs.SourceSettings
 import org.koitharu.kotatsu.domain.MangaLoaderContext
 import org.koitharu.kotatsu.utils.ext.*
+import java.util.*
+import kotlin.collections.ArrayList
 
 open class MangaLibRepository(loaderContext: MangaLoaderContext) :
 	RemoteMangaRepository(loaderContext) {
@@ -19,7 +20,7 @@ open class MangaLibRepository(loaderContext: MangaLoaderContext) :
 
 	override val source = MangaSource.MANGALIB
 
-	override val sortOrders = arraySetOf(
+	override val sortOrders: Set<SortOrder> = EnumSet.of(
 		SortOrder.RATING,
 		SortOrder.ALPHABETICAL,
 		SortOrder.POPULARITY,

app/src/main/java/org/koitharu/kotatsu/core/parser/site/MangaTownRepository.kt

@@ -15,7 +15,7 @@ class MangaTownRepository(loaderContext: MangaLoaderContext) :
 
 	override val source = MangaSource.MANGATOWN
 
-	override val sortOrders = arraySetOf(
+	override val sortOrders: Set<SortOrder> = EnumSet.of(
 		SortOrder.ALPHABETICAL,
 		SortOrder.RATING,
 		SortOrder.POPULARITY,

app/src/main/java/org/koitharu/kotatsu/core/parser/site/MangareadRepository.kt

@@ -7,6 +7,7 @@ import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.core.prefs.SourceSettings
 import org.koitharu.kotatsu.domain.MangaLoaderContext
 import org.koitharu.kotatsu.utils.ext.*
+import java.util.*
 
 class MangareadRepository(
 	loaderContext: MangaLoaderContext
@@ -14,7 +15,10 @@ class MangareadRepository(
 
 	override val source = MangaSource.MANGAREAD
 
-	override val sortOrders = arraySetOf(SortOrder.UPDATED, SortOrder.POPULARITY)
+	override val sortOrders: Set<SortOrder> = EnumSet.of(
+		SortOrder.UPDATED,
+		SortOrder.POPULARITY
+	)
 
 	override suspend fun getList(
 		offset: Int,

app/src/main/java/org/koitharu/kotatsu/core/parser/site/NudeMoonRepository.kt

@@ -7,13 +7,18 @@ import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.core.prefs.SourceSettings
 import org.koitharu.kotatsu.domain.MangaLoaderContext
 import org.koitharu.kotatsu.utils.ext.*
+import java.util.*
 import java.util.regex.Pattern
 
 class NudeMoonRepository(loaderContext: MangaLoaderContext) : RemoteMangaRepository(loaderContext) {
 
 	override val source = MangaSource.NUDEMOON
 
-	override val sortOrders = arraySetOf(SortOrder.NEWEST, SortOrder.POPULARITY, SortOrder.RATING)
+	override val sortOrders: Set<SortOrder> = EnumSet.of(
+		SortOrder.NEWEST,
+		SortOrder.POPULARITY,
+		SortOrder.RATING
+	)
 
 	init {
 		loaderContext.insertCookies(
@@ -35,9 +40,7 @@ class NudeMoonRepository(loaderContext: MangaLoaderContext) : RemoteMangaReposit
 			tag != null -> "https://$domain/tags/${tag.key}&rowstart=$offset"
 			else -> "https://$domain/all_manga?${getSortKey(sortOrder)}&rowstart=$offset"
 		}
-		val doc = loaderContext.httpGet(url) {
+		val doc = loaderContext.httpGet(url).parseHtml()
-			addHeader("Cookie", "NMfYa=1; nm_mobile=0;")
-		}.parseHtml()
 		val root = doc.body().run {
 			selectFirst("td.shoutbox") ?: selectFirst("td.main-bg")
 		} ?: throw ParseException("Cannot find root")

app/src/main/java/org/koitharu/kotatsu/core/prefs/AppSettings.kt

@@ -7,6 +7,7 @@ import androidx.appcompat.app.AppCompatDelegate
 import androidx.collection.arraySetOf
 import androidx.core.content.edit
 import androidx.preference.PreferenceManager
+import org.koitharu.kotatsu.core.model.ZoomMode
 import org.koitharu.kotatsu.core.parser.LocalMangaRepository
 import org.koitharu.kotatsu.utils.delegates.prefs.*
 import java.io.File
@@ -18,13 +19,13 @@ class AppSettings private constructor(private val prefs: SharedPreferences) :
 		PreferenceManager.getDefaultSharedPreferences(context)
 	)
 
-	var listMode by EnumPreferenceDelegate(
+	var listMode by IntEnumPreferenceDelegate(
 		ListMode::class.java,
 		KEY_LIST_MODE,
 		ListMode.DETAILED_LIST
 	)
 
-	var defaultSection by EnumPreferenceDelegate(
+	var defaultSection by IntEnumPreferenceDelegate(
 		AppSection::class.java,
 		KEY_APP_SECTION,
 		AppSection.HISTORY
@@ -66,6 +67,12 @@ class AppSettings private constructor(private val prefs: SharedPreferences) :
 
 	val isPreferRtlReader by BoolPreferenceDelegate(KEY_READER_PREFER_RTL, false)
 
+	val zoomMode by EnumPreferenceDelegate(
+		ZoomMode::class.java,
+		KEY_ZOOM_MODE,
+		ZoomMode.FIT_CENTER
+	)
+
 	val trackSources by StringSetPreferenceDelegate(
 		KEY_TRACK_SOURCES,
 		arraySetOf(TRACK_FAVOURITES, TRACK_HISTORY)
@@ -143,5 +150,6 @@ class AppSettings private constructor(private val prefs: SharedPreferences) :
 		const val KEY_APP_PASSWORD = "app_password"
 		const val KEY_PROTECT_APP = "protect_app"
 		const val KEY_APP_VERSION = "app_version"
+		const val KEY_ZOOM_MODE = "zoom_mode"
 	}
 }

app/src/main/java/org/koitharu/kotatsu/domain/MangaLoaderContext.kt

@@ -13,20 +13,16 @@ open class MangaLoaderContext : KoinComponent {
 	private val okHttp by inject<OkHttpClient>()
 	private val cookieJar by inject<CookieJar>()
 
-	suspend fun httpGet(url: String, block: (Request.Builder.() -> Unit)? = null): Response {
+	suspend fun httpGet(url: String): Response {
 		val request = Request.Builder()
 			.get()
 			.url(url)
-		if (block != null) {
-			request.block()
-		}
 		return okHttp.newCall(request.build()).await()
 	}
 
 	suspend fun httpPost(
 		url: String,
-		form: Map<String, String>,
+		form: Map<String, String>
-		block: (Request.Builder.() -> Unit)? = null
 	): Response {
 		val body = FormBody.Builder()
 		form.forEach { (k, v) ->
@@ -35,16 +31,12 @@ open class MangaLoaderContext : KoinComponent {
 		val request = Request.Builder()
 			.post(body.build())
 			.url(url)
-		if (block != null) {
-			request.block()
-		}
 		return okHttp.newCall(request.build()).await()
 	}
 
 	suspend fun httpPost(
 		url: String,
-		payload: String,
+		payload: String
-		block: (Request.Builder.() -> Unit)? = null
 	): Response {
 		val body = FormBody.Builder()
 		payload.split('&').forEach {
@@ -58,9 +50,6 @@ open class MangaLoaderContext : KoinComponent {
 		val request = Request.Builder()
 			.post(body.build())
 			.url(url)
-		if (block != null) {
-			request.block()
-		}
 		return okHttp.newCall(request.build()).await()
 	}
 

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

@@ -1,5 +0,0 @@
-package org.koitharu.kotatsu.ui.reader
-
-enum class ReaderAction {
-	REPLACE, PREPEND, APPEND
-}

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

@@ -96,7 +96,7 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 		ViewCompat.setOnApplyWindowInsetsListener(rootLayout, this)
 
 		settings.subscribe(this)
-		loadSettings()
+		loadSwitchSettings()
 		orientationHelper.observeAutoOrientation()
 			.onEach {
 				toolbar_bottom.menu.findItem(R.id.action_screen_rotate).isVisible = !it
@@ -370,7 +370,11 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 	}
 
 	override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences?, key: String?) {
-		loadSettings()
+		when (key) {
+			AppSettings.KEY_READER_SWITCHERS -> loadSwitchSettings()
+			AppSettings.KEY_READER_ANIMATION,
+			AppSettings.KEY_ZOOM_MODE -> reader?.recreateAdapter()
+		}
 	}
 
 	private fun showWaitWhileLoading() {
@@ -410,7 +414,7 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 			.build()
 	}
 
-	private fun loadSettings() {
+	private fun loadSwitchSettings() {
 		settings.readerPageSwitch.let {
 			isTapSwitchEnabled = it.contains(AppSettings.PAGE_SWITCH_TAPS)
 			isVolumeKeysSwitchEnabled = it.contains(AppSettings.PAGE_SWITCH_VOLUME_KEYS)

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

@@ -3,6 +3,7 @@ package org.koitharu.kotatsu.ui.reader.base
 import android.content.Context
 import android.os.Bundle
 import android.view.View
+import androidx.annotation.CallSuper
 import androidx.collection.LongSparseArray
 import androidx.core.view.postDelayed
 import kotlinx.coroutines.CancellationException
@@ -131,6 +132,11 @@ abstract class AbstractReader(contentLayoutId: Int) : BaseFragment(contentLayout
 		super.onDestroy()
 	}
 
+	@CallSuper
+	open fun recreateAdapter() {
+		adapter = onCreateAdapter(pages)
+	}
+
 	fun getPages(): List<MangaPage>? {
 		val chapterId = (pages.getOrNull(getCurrentItem()) ?: return null).chapterId
 		// TODO optimize

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

@@ -4,7 +4,10 @@ import android.net.Uri
 import androidx.core.net.toUri
 import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
 import kotlinx.coroutines.*
+import org.koin.core.component.inject
 import org.koitharu.kotatsu.core.model.MangaPage
+import org.koitharu.kotatsu.core.model.ZoomMode
+import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.utils.ext.launchAfter
 import org.koitharu.kotatsu.utils.ext.launchInstead
@@ -14,8 +17,10 @@ import java.io.IOException
 class PageHolderDelegate(
 	private val loader: PageLoader,
 	private val callback: Callback
-) : SubsamplingScaleImageView.DefaultOnImageEventListener(), CoroutineScope by loader {
+) : SubsamplingScaleImageView.DefaultOnImageEventListener(),
+	CoroutineScope by loader {
 
+	private val settings by loader.inject<AppSettings>()
 	private var state = State.EMPTY
 	private var job: Job? = null
 	private var file: File? = null
@@ -36,7 +41,7 @@ class PageHolderDelegate(
 
 	override fun onReady() {
 		state = State.SHOWING
-		callback.onImageShowing()
+		callback.onImageShowing(settings.zoomMode)
 	}
 
 	override fun onImageLoaded() {
@@ -79,7 +84,7 @@ class PageHolderDelegate(
 				state = State.LOADED
 				callback.onImageReady(file.toUri())
 			} catch (e: CancellationException) {
-				//do nothing
+				// do nothing
 			} catch (e: Exception) {
 				state = State.ERROR
 				callback.onError(e)
@@ -99,7 +104,7 @@ class PageHolderDelegate(
 
 		fun onImageReady(uri: Uri)
 
-		fun onImageShowing()
+		fun onImageShowing(zoom: ZoomMode)
 
 		fun onImageShown()
 	}

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

@@ -0,0 +1,48 @@
+package org.koitharu.kotatsu.ui.reader.reversed
+
+import android.graphics.PointF
+import android.view.ViewGroup
+import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
+import kotlinx.android.synthetic.main.item_page.*
+import org.koitharu.kotatsu.core.model.ZoomMode
+import org.koitharu.kotatsu.ui.reader.PageLoader
+import org.koitharu.kotatsu.ui.reader.standard.PageHolder
+
+class ReversedPageHolder(parent: ViewGroup, loader: PageLoader) : PageHolder(parent, loader) {
+
+	override fun onImageShowing(zoom: ZoomMode) {
+		ssiv.maxScale = 2f * maxOf(
+			ssiv.width / ssiv.sWidth.toFloat(),
+			ssiv.height / ssiv.sHeight.toFloat()
+		)
+		when (zoom) {
+			ZoomMode.FIT_CENTER -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CENTER_INSIDE)
+				ssiv.resetScaleAndCenter()
+			}
+			ZoomMode.FIT_HEIGHT -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CUSTOM)
+				ssiv.minScale = ssiv.height / ssiv.sHeight.toFloat()
+				ssiv.setScaleAndCenter(
+					ssiv.minScale,
+					PointF(ssiv.sWidth.toFloat(), ssiv.sHeight / 2f)
+				)
+			}
+			ZoomMode.FIT_WIDTH -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CUSTOM)
+				ssiv.minScale = ssiv.width / ssiv.sWidth.toFloat()
+				ssiv.setScaleAndCenter(
+					ssiv.minScale,
+					PointF(ssiv.sWidth / 2f, 0f)
+				)
+			}
+			ZoomMode.KEEP_START -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CENTER_INSIDE)
+				ssiv.setScaleAndCenter(
+					ssiv.maxScale,
+					PointF(ssiv.sWidth.toFloat(), 0f)
+				)
+			}
+		}
+	}
+}

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

@@ -5,14 +5,13 @@ import org.koitharu.kotatsu.ui.base.list.BaseViewHolder
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.base.BaseReaderAdapter
 import org.koitharu.kotatsu.ui.reader.base.ReaderPage
-import org.koitharu.kotatsu.ui.reader.standard.PageHolder
 
 class ReversedPagesAdapter(
 	pages: List<ReaderPage>,
 	private val loader: PageLoader
 ) : BaseReaderAdapter(pages) {
 
-	override fun onCreateViewHolder(parent: ViewGroup) = PageHolder(parent, loader)
+	override fun onCreateViewHolder(parent: ViewGroup) = ReversedPageHolder(parent, loader)
 
 	override fun onBindViewHolder(holder: BaseViewHolder<ReaderPage, Unit>, position: Int) {
 		super.onBindViewHolder(holder, reversed(position))

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

@@ -15,6 +15,7 @@ import org.koitharu.kotatsu.ui.reader.base.ReaderPage
 import org.koitharu.kotatsu.ui.reader.standard.PageAnimTransformer
 import org.koitharu.kotatsu.ui.reader.standard.PagerPaginationListener
 import org.koitharu.kotatsu.utils.ext.doOnPageChanged
+import org.koitharu.kotatsu.utils.ext.swapAdapter
 import org.koitharu.kotatsu.utils.ext.withArgs
 
 class ReversedReaderFragment : AbstractReader(R.layout.fragment_reader_standard),
@@ -56,6 +57,11 @@ class ReversedReaderFragment : AbstractReader(R.layout.fragment_reader_standard)
 		return ReversedPagesAdapter(dataSet, loader)
 	}
 
+	override fun recreateAdapter() {
+		super.recreateAdapter()
+		pager.swapAdapter(adapter)
+	}
+
 	override fun getCurrentItem() = reversed(pager.currentItem)
 
 	override fun setCurrentItem(position: Int, isSmooth: Boolean) {

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

@@ -1,19 +1,22 @@
 package org.koitharu.kotatsu.ui.reader.standard
 
+import android.graphics.PointF
 import android.net.Uri
 import android.view.View
 import android.view.ViewGroup
 import androidx.core.view.isVisible
 import com.davemorrissey.labs.subscaleview.ImageSource
+import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
 import kotlinx.android.synthetic.main.item_page.*
 import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.core.model.ZoomMode
 import org.koitharu.kotatsu.ui.base.list.BaseViewHolder
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.base.PageHolderDelegate
 import org.koitharu.kotatsu.ui.reader.base.ReaderPage
 import org.koitharu.kotatsu.utils.ext.getDisplayMessage
 
-class PageHolder(parent: ViewGroup, loader: PageLoader) :
+open class PageHolder(parent: ViewGroup, loader: PageLoader) :
 	BaseViewHolder<ReaderPage, Unit>(parent, R.layout.item_page),
 	PageHolderDelegate.Callback, View.OnClickListener {
 
@@ -43,12 +46,40 @@ class PageHolder(parent: ViewGroup, loader: PageLoader) :
 		ssiv.setImage(ImageSource.uri(uri))
 	}
 
-	override fun onImageShowing() {
+	override fun onImageShowing(zoom: ZoomMode) {
 		ssiv.maxScale = 2f * maxOf(
 			ssiv.width / ssiv.sWidth.toFloat(),
 			ssiv.height / ssiv.sHeight.toFloat()
 		)
-		ssiv.resetScaleAndCenter()
+		when (zoom) {
+			ZoomMode.FIT_CENTER -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CENTER_INSIDE)
+				ssiv.resetScaleAndCenter()
+			}
+			ZoomMode.FIT_HEIGHT -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CUSTOM)
+				ssiv.minScale = ssiv.height / ssiv.sHeight.toFloat()
+				ssiv.setScaleAndCenter(
+					ssiv.minScale,
+					PointF(0f, ssiv.sHeight / 2f)
+				)
+			}
+			ZoomMode.FIT_WIDTH -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CUSTOM)
+				ssiv.minScale = ssiv.width / ssiv.sWidth.toFloat()
+				ssiv.setScaleAndCenter(
+					ssiv.minScale,
+					PointF(ssiv.sWidth / 2f, 0f)
+				)
+			}
+			ZoomMode.KEEP_START -> {
+				ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CENTER_INSIDE)
+				ssiv.setScaleAndCenter(
+					ssiv.maxScale,
+					PointF(0f, 0f)
+				)
+			}
+		}
 	}
 
 	override fun onImageShown() {

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

@@ -13,6 +13,7 @@ import org.koitharu.kotatsu.ui.reader.base.AbstractReader
 import org.koitharu.kotatsu.ui.reader.base.BaseReaderAdapter
 import org.koitharu.kotatsu.ui.reader.base.ReaderPage
 import org.koitharu.kotatsu.utils.ext.doOnPageChanged
+import org.koitharu.kotatsu.utils.ext.swapAdapter
 import org.koitharu.kotatsu.utils.ext.withArgs
 
 class PagerReaderFragment : AbstractReader(R.layout.fragment_reader_standard),
@@ -52,6 +53,11 @@ class PagerReaderFragment : AbstractReader(R.layout.fragment_reader_standard),
 		return PagesAdapter(dataSet, loader)
 	}
 
+	override fun recreateAdapter() {
+		super.recreateAdapter()
+		pager.swapAdapter(adapter)
+	}
+
 	override fun getCurrentItem() = pager.currentItem
 
 	override fun setCurrentItem(position: Int, isSmooth: Boolean) {

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

@@ -8,6 +8,7 @@ import com.davemorrissey.labs.subscaleview.ImageSource
 import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
 import kotlinx.android.synthetic.main.item_page_webtoon.*
 import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.core.model.ZoomMode
 import org.koitharu.kotatsu.ui.base.list.BaseViewHolder
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.base.PageHolderDelegate
@@ -46,7 +47,7 @@ class WebtoonHolder(parent: ViewGroup, private val loader: PageLoader) :
 		ssiv.setImage(ImageSource.uri(uri))
 	}
 
-	override fun onImageShowing() {
+	override fun onImageShowing(zoom: ZoomMode) {
 		ssiv.maxScale = 2f * ssiv.width / ssiv.sWidth.toFloat()
 		ssiv.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CUSTOM)
 		ssiv.minScale = ssiv.width / ssiv.sWidth.toFloat()

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

@@ -32,6 +32,11 @@ class WebtoonReaderFragment : AbstractReader(R.layout.fragment_reader_webtoon) {
 		return WebtoonAdapter(dataSet, loader)
 	}
 
+	override fun recreateAdapter() {
+		super.recreateAdapter()
+		recyclerView.swapAdapter(adapter, true)
+	}
+
 	override fun onDestroyView() {
 		paginationListener = null
 		super.onDestroyView()

app/src/main/java/org/koitharu/kotatsu/ui/settings/MainSettingsFragment.kt

@@ -16,6 +16,7 @@ import kotlinx.coroutines.launch
 import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.model.MangaSource
+import org.koitharu.kotatsu.core.model.ZoomMode
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.prefs.ListMode
 import org.koitharu.kotatsu.ui.base.BasePreferenceFragment
@@ -26,6 +27,7 @@ import org.koitharu.kotatsu.ui.settings.utils.MultiSummaryProvider
 import org.koitharu.kotatsu.ui.tracker.TrackWorker
 import org.koitharu.kotatsu.utils.ext.getStorageName
 import org.koitharu.kotatsu.utils.ext.md5
+import org.koitharu.kotatsu.utils.ext.names
 import org.koitharu.kotatsu.utils.ext.viewLifecycleScope
 import java.io.File
 
@@ -60,6 +62,11 @@ class MainSettingsFragment : BasePreferenceFragment(R.string.settings),
 			summary = settings.getStorageDir(context)?.getStorageName(context)
 				?: getString(R.string.not_available)
 		}
+		findPreference<ListPreference>(AppSettings.KEY_ZOOM_MODE)?.let {
+			it.entryValues = ZoomMode.values().names()
+			it.setDefaultValue(ZoomMode.FIT_CENTER.name)
+			it.summaryProvider = ListPreference.SimpleSummaryProvider.getInstance()
+		}
 		findPreference<SwitchPreference>(AppSettings.KEY_PROTECT_APP)?.isChecked =
 			!settings.appPassword.isNullOrEmpty()
 		findPreference<Preference>(AppSettings.KEY_APP_VERSION)?.run {

app/src/main/java/org/koitharu/kotatsu/ui/settings/ReaderSettingsFragment.kt

@@ -2,11 +2,14 @@ package org.koitharu.kotatsu.ui.settings
 
 import android.os.Bundle
 import android.view.View
+import androidx.preference.ListPreference
 import androidx.preference.MultiSelectListPreference
 import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.core.model.ZoomMode
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.ui.base.BasePreferenceFragment
 import org.koitharu.kotatsu.ui.settings.utils.MultiSummaryProvider
+import org.koitharu.kotatsu.utils.ext.names
 
 class ReaderSettingsFragment : BasePreferenceFragment(R.string.reader_settings) {
 
@@ -19,5 +22,10 @@ class ReaderSettingsFragment : BasePreferenceFragment(R.string.reader_settings)
 		findPreference<MultiSelectListPreference>(AppSettings.KEY_READER_SWITCHERS)?.let {
 			it.summaryProvider = MultiSummaryProvider(R.string.gestures_only)
 		}
+		findPreference<ListPreference>(AppSettings.KEY_ZOOM_MODE)?.let {
+			it.entryValues = ZoomMode.values().names()
+			it.setDefaultValue(ZoomMode.FIT_CENTER.name)
+			it.summaryProvider = ListPreference.SimpleSummaryProvider.getInstance()
+		}
 	}
 }

app/src/main/java/org/koitharu/kotatsu/utils/delegates/prefs/EnumPreferenceDelegate.kt

@@ -9,20 +9,19 @@ class EnumPreferenceDelegate<E : Enum<*>>(
 	private val cls: Class<E>,
 	private val key: String,
 	private val defValue: E
-) :
+) : ReadWriteProperty<SharedPreferences, E> {
-	ReadWriteProperty<SharedPreferences, E> {
 
 	override fun getValue(thisRef: SharedPreferences, property: KProperty<*>): E {
-		val ord = thisRef.getInt(key, -1)
+		val name = thisRef.getString(key, null)
-		if (ord == -1) {
+		if (name === null) {
 			return defValue
 		}
-		return cls.enumConstants?.firstOrNull { it.ordinal == ord } ?: defValue
+		return cls.enumConstants?.find { it.name == name } ?: defValue
 	}
 
 	override fun setValue(thisRef: SharedPreferences, property: KProperty<*>, value: E) {
 		thisRef.edit {
-			putInt(key, value.ordinal)
+			putString(key, value.name)
 		}
 	}
 }

app/src/main/java/org/koitharu/kotatsu/utils/delegates/prefs/IntEnumPreferenceDelegate.kt

@@ -0,0 +1,28 @@
+package org.koitharu.kotatsu.utils.delegates.prefs
+
+import android.content.SharedPreferences
+import androidx.core.content.edit
+import kotlin.properties.ReadWriteProperty
+import kotlin.reflect.KProperty
+
+@Deprecated("")
+class IntEnumPreferenceDelegate<E : Enum<*>>(
+	private val cls: Class<E>,
+	private val key: String,
+	private val defValue: E
+) : ReadWriteProperty<SharedPreferences, E> {
+
+	override fun getValue(thisRef: SharedPreferences, property: KProperty<*>): E {
+		val ord = thisRef.getInt(key, -1)
+		if (ord == -1) {
+			return defValue
+		}
+		return cls.enumConstants?.getOrNull(ord) ?: defValue
+	}
+
+	override fun setValue(thisRef: SharedPreferences, property: KProperty<*>, value: E) {
+		thisRef.edit {
+			putInt(key, value.ordinal)
+		}
+	}
+}

app/src/main/java/org/koitharu/kotatsu/utils/ext/CollectionExt.kt

@@ -66,4 +66,10 @@ inline fun <T> Collection<T>.associateByLong(selector: (T) -> Long): LongSparseA
 		result.put(selector(item), item)
 	}
 	return result
-}
+}
+
+inline fun <T, reified R> Array<T>.mapToArray(transform: (T) -> R): Array<R> = Array(size) { i ->
+	transform(get(i))
+}
+
+fun <T : Enum<T>> Array<T>.names() = mapToArray { it.name }

app/src/main/java/org/koitharu/kotatsu/utils/ext/ViewExt.kt

@@ -200,4 +200,12 @@ fun RecyclerView.findCenterViewPosition(): Int {
 	val centerY = height / 2f
 	val view = findChildViewUnder(centerX, centerY) ?: return RecyclerView.NO_POSITION
 	return getChildAdapterPosition(view)
+}
+
+fun ViewPager2.swapAdapter(newAdapter: RecyclerView.Adapter<*>?) {
+	val position = currentItem
+	adapter = newAdapter
+	if (adapter != null && position != RecyclerView.NO_POSITION) {
+		currentItem = position
+	}
 }

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

@@ -163,4 +163,9 @@
 	<string name="prefer_rtl_reader">Предпочитать режим Справа налево</string>
 	<string name="prefer_rtl_reader_summary">Вы можете настроить режим чтения для каждой манги отдельно</string>
 	<string name="create_category">Создать категорию</string>
+	<string name="scale_mode">Масштабирование</string>
+	<string name="zoom_mode_fit_center">Вписать в экран</string>
+	<string name="zoom_mode_fit_height">Подогнать по высоте</string>
+	<string name="zoom_mode_fit_width">Подогнать по ширине</string>
+	<string name="zoom_mode_keep_start">Исходный размер</string>
 </resources>

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

@@ -9,6 +9,12 @@
 		<item>@string/taps_on_edges</item>
 		<item>@string/volume_buttons</item>
 	</string-array>
+	<string-array name="zoom_modes">
+		<item>@string/zoom_mode_fit_center</item>
+		<item>@string/zoom_mode_fit_height</item>
+		<item>@string/zoom_mode_fit_width</item>
+		<item>@string/zoom_mode_keep_start</item>
+	</string-array>
 	<string-array name="track_sources">
 		<item>@string/favourites</item>
 		<item>@string/history</item>

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

@@ -165,4 +165,9 @@
 	<string name="prefer_rtl_reader_summary">You can set up the reading mode for each manga separately</string>
 	<string name="create_category">New category</string>
 	<string name="report_github">Create issue on GitHub</string>
+	<string name="scale_mode">Scale mode</string>
+	<string name="zoom_mode_fit_center">Fit center</string>
+	<string name="zoom_mode_fit_height">Fit to height</string>
+	<string name="zoom_mode_fit_width">Fit to width</string>
+	<string name="zoom_mode_keep_start">Keep at start</string>
 </resources>

app/src/main/res/xml/pref_main.xml

@@ -70,6 +70,12 @@
 		android:title="@string/pages_animation"
 		app:iconSpaceReserved="false" />
 
+	<ListPreference
+		android:entries="@array/zoom_modes"
+		android:key="zoom_mode"
+		android:title="@string/scale_mode"
+		app:iconSpaceReserved="false" />
+
 	<SwitchPreference
 		android:defaultValue="false"
 		android:key="reader_prefer_rtl"

app/src/main/res/xml/pref_reader.xml

@@ -17,6 +17,12 @@
 		android:title="@string/pages_animation"
 		app:iconSpaceReserved="false" />
 
+	<ListPreference
+		android:entries="@array/zoom_modes"
+		android:key="zoom_mode"
+		android:title="@string/scale_mode"
+		app:iconSpaceReserved="false" />
+
 	<SwitchPreference
 		android:defaultValue="false"
 		android:key="reader_prefer_rtl"