Use page preview in reader while loading

app/src/main/kotlin/org/koitharu/kotatsu/core/util/RetainedLifecycleCoroutineScope.kt

@@ -5,6 +5,7 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
+import kotlinx.coroutines.launch
 import kotlin.coroutines.CoroutineContext
 
 class RetainedLifecycleCoroutineScope(
@@ -14,7 +15,9 @@ class RetainedLifecycleCoroutineScope(
 	override val coroutineContext: CoroutineContext = SupervisorJob() + Dispatchers.Main.immediate
 
 	init {
-		lifecycle.addOnClearedListener(this)
+		launch(Dispatchers.Main.immediate) {
+			lifecycle.addOnClearedListener(this@RetainedLifecycleCoroutineScope)
+		}
 	}
 
 	override fun onCleared() {

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/pager/pages/PageThumbnailAD.kt

@@ -3,10 +3,12 @@ package org.koitharu.kotatsu.details.ui.pager.pages
 import androidx.lifecycle.LifecycleOwner
 import coil3.ImageLoader
 import coil3.request.allowRgb565
+import coil3.request.transformations
 import coil3.size.Scale
 import coil3.size.Size
 import com.hannesdorfmann.adapterdelegates4.dsl.adapterDelegateViewBinding
 import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.core.ui.image.TrimTransformation
 import org.koitharu.kotatsu.core.ui.list.AdapterDelegateClickListenerAdapter
 import org.koitharu.kotatsu.core.ui.list.OnListItemClickListener
 import org.koitharu.kotatsu.core.util.ext.decodeRegion
@@ -43,6 +45,7 @@ fun pageThumbnailAD(
 			size(thumbSize)
 			scale(Scale.FILL)
 			allowRgb565(true)
+			transformations(TrimTransformation())
 			decodeRegion(0)
 			mangaSourceExtra(item.page.source)
 			enqueueWith(coil)

app/src/main/kotlin/org/koitharu/kotatsu/reader/domain/PageLoader.kt

@@ -8,9 +8,15 @@ import androidx.collection.LongSparseArray
 import androidx.collection.set
 import androidx.core.net.toFile
 import androidx.core.net.toUri
+import coil3.BitmapImage
+import coil3.Image
+import coil3.ImageLoader
+import coil3.memory.MemoryCache
+import coil3.request.ImageRequest
+import coil3.request.transformations
+import coil3.toBitmap
 import com.davemorrissey.labs.subscaleview.ImageSource
 import dagger.hilt.android.ActivityRetainedLifecycle
-import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.android.scopes.ActivityRetainedScoped
 import kotlinx.coroutines.CoroutineExceptionHandler
 import kotlinx.coroutines.Deferred
@@ -24,6 +30,7 @@ import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.Semaphore
 import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.sync.withPermit
+import kotlinx.coroutines.withContext
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import okio.use
@@ -36,9 +43,9 @@ import org.koitharu.kotatsu.core.network.imageproxy.ImageProxyInterceptor
 import org.koitharu.kotatsu.core.parser.CachingMangaRepository
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.core.ui.image.TrimTransformation
 import org.koitharu.kotatsu.core.util.FileSize
 import org.koitharu.kotatsu.core.util.MimeTypes
-import org.koitharu.kotatsu.core.util.RetainedLifecycleCoroutineScope
 import org.koitharu.kotatsu.core.util.ext.URI_SCHEME_ZIP
 import org.koitharu.kotatsu.core.util.ext.cancelChildrenAndJoin
 import org.koitharu.kotatsu.core.util.ext.compressToPNG
@@ -49,6 +56,8 @@ import org.koitharu.kotatsu.core.util.ext.isFileUri
 import org.koitharu.kotatsu.core.util.ext.isNotEmpty
 import org.koitharu.kotatsu.core.util.ext.isPowerSaveMode
 import org.koitharu.kotatsu.core.util.ext.isZipUri
+import org.koitharu.kotatsu.core.util.ext.lifecycleScope
+import org.koitharu.kotatsu.core.util.ext.mangaSourceExtra
 import org.koitharu.kotatsu.core.util.ext.printStackTraceDebug
 import org.koitharu.kotatsu.core.util.ext.ramAvailable
 import org.koitharu.kotatsu.core.util.ext.toMimeType
@@ -76,13 +85,14 @@ class PageLoader @Inject constructor(
 	lifecycle: ActivityRetainedLifecycle,
 	@MangaHttpClient private val okHttp: OkHttpClient,
 	private val cache: PagesCache,
+	private val coil: ImageLoader,
 	private val settings: AppSettings,
 	private val mangaRepositoryFactory: MangaRepository.Factory,
 	private val imageProxyInterceptor: ImageProxyInterceptor,
 	private val downloadSlowdownDispatcher: DownloadSlowdownDispatcher,
 ) {
 
-	val loaderScope = RetainedLifecycleCoroutineScope(lifecycle) + InternalErrorHandler() + Dispatchers.Default
+	val loaderScope = lifecycle.lifecycleScope + InternalErrorHandler() + Dispatchers.Default
 
 	private val tasks = LongSparseArray<ProgressDeferred<Uri, Float>>()
 	private val semaphore = Semaphore(3)
@@ -121,6 +131,41 @@ class PageLoader @Inject constructor(
 		}
 	}
 
+	suspend fun loadPreview(page: MangaPage): ImageSource? {
+		val preview = page.preview
+		if (preview.isNullOrEmpty()) {
+			return null
+		}
+		val request = ImageRequest.Builder(context)
+			.data(preview)
+			.mangaSourceExtra(page.source)
+			.transformations(TrimTransformation())
+			.build()
+		return coil.execute(request).image?.toImageSource()
+	}
+
+	fun peekPreviewSource(preview: String?): ImageSource? {
+		if (preview.isNullOrEmpty()) {
+			return null
+		}
+		coil.memoryCache?.let { cache ->
+			val key = MemoryCache.Key(preview)
+			cache[key]?.image?.let {
+				return if (it is BitmapImage) {
+					ImageSource.cachedBitmap(it.toBitmap())
+				} else {
+					ImageSource.bitmap(it.toBitmap())
+				}
+			}
+		}
+		coil.diskCache?.let { cache ->
+			cache.openSnapshot(preview)?.use { snapshot ->
+				return ImageSource.file(snapshot.data.toFile())
+			}
+		}
+		return null
+	}
+
 	fun loadPageAsync(page: MangaPage, force: Boolean): ProgressDeferred<Uri, Float> {
 		var task = tasks[page.id]?.takeIf { it.isValid() }
 		if (force) {
@@ -237,7 +282,7 @@ class PageLoader @Inject constructor(
 		if (!skipCache) {
 			cache.get(pageUrl)?.let { return it.toUri() }
 		}
-		val uri = Uri.parse(pageUrl)
+		val uri = pageUrl.toUri()
 		return when {
 			uri.isZipUri() -> if (uri.scheme == URI_SCHEME_ZIP) {
 				uri
@@ -264,6 +309,12 @@ class PageLoader @Inject constructor(
 		return context.ramAvailable <= FileSize.MEGABYTES.convert(PREFETCH_MIN_RAM_MB, FileSize.BYTES)
 	}
 
+	private fun Image.toImageSource(): ImageSource = if (this is BitmapImage) {
+		ImageSource.cachedBitmap(toBitmap())
+	} else {
+		ImageSource.bitmap(toBitmap())
+	}
+
 	private fun Deferred<Uri>.isValid(): Boolean {
 		return getCompletionResultOrNull()?.map { uri ->
 			uri.exists() && uri.isTargetNotEmpty()

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

@@ -20,7 +20,6 @@ import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.plus
 import kotlinx.coroutines.withContext
-import kotlinx.coroutines.yield
 import org.koitharu.kotatsu.core.exceptions.resolve.ExceptionResolver
 import org.koitharu.kotatsu.core.os.NetworkState
 import org.koitharu.kotatsu.core.util.ext.printStackTraceDebug
@@ -108,19 +107,29 @@ class PageHolderDelegate(
 	}
 
 	override fun onReady() {
+		if (state >= State.LOADED) {
 			state = State.SHOWING
 			error = null
-		callback.onImageShowing(readerSettings)
+			callback.onImageShowing(readerSettings, isPreview = false)
+		} else if (state == State.LOADING_WITH_PREVIEW) {
+			callback.onImageShowing(readerSettings, isPreview = true)
+		}
 	}
 
 	override fun onImageLoaded() {
+		if (state >= State.LOADED) {
 			state = State.SHOWN
 			error = null
 			callback.onImageShown()
 		}
+	}
 
 	override fun onImageLoadError(e: Throwable) {
 		e.printStackTraceDebug()
+		if (state < State.LOADED) {
+			// ignore preview error
+			return
+		}
 		val uri = this.uri
 		error = e
 		if (state == State.LOADED && e is IOException && uri != null && uri.toFileOrNull()?.exists() != false) {
@@ -133,7 +142,7 @@ class PageHolderDelegate(
 
 	override fun onChanged(value: ReaderSettings) {
 		if (state == State.SHOWN) {
-			callback.onImageShowing(readerSettings)
+			callback.onImageShowing(readerSettings, isPreview = false)
 		}
 		callback.onConfigChanged()
 	}
@@ -172,21 +181,25 @@ class PageHolderDelegate(
 		}
 	}
 
-	private suspend fun doLoad(data: MangaPage, force: Boolean) {
+	private suspend fun doLoad(data: MangaPage, force: Boolean) = coroutineScope {
 		state = State.LOADING
 		error = null
 		callback.onLoadingStarted()
-		yield()
+		launch {
+			val preview = loader.loadPreview(data) ?: return@launch
+			if (state == State.LOADING) {
+				state = State.LOADING_WITH_PREVIEW
+				callback.onPreviewReady(preview)
+			}
+		}
 		try {
 			val task = withContext(Dispatchers.Default) {
 				loader.loadPageAsync(data, force)
 			}
-			uri = coroutineScope {
 			val progressObserver = observeProgress(this, task.progressAsFlow())
 			val file = task.await()
 			progressObserver.cancelAndJoin()
-				file
+			uri = file
-			}
 			state = State.LOADED
 			cachedBounds = if (readerSettings.isPagesCropEnabled(isWebtoon)) {
 				loader.getTrimmedBounds(checkNotNull(uri))
@@ -223,7 +236,7 @@ class PageHolderDelegate(
 	}
 
 	enum class State {
-		EMPTY, LOADING, LOADED, CONVERTING, CONVERTED, SHOWING, SHOWN, ERROR
+		EMPTY, LOADING, LOADING_WITH_PREVIEW, LOADED, CONVERTING, CONVERTED, SHOWING, SHOWN, ERROR
 	}
 
 	interface Callback {
@@ -232,9 +245,11 @@ class PageHolderDelegate(
 
 		fun onError(e: Throwable)
 
+		fun onPreviewReady(source: ImageSource)
+
 		fun onImageReady(source: ImageSource)
 
-		fun onImageShowing(settings: ReaderSettings)
+		fun onImageShowing(settings: ReaderSettings, isPreview: Boolean)
 
 		fun onImageShown()
 

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

@@ -35,7 +35,7 @@ class DoublePageHolder(
 			.gravity = (if (isEven) Gravity.START else Gravity.END) or Gravity.BOTTOM
 	}
 
-	override fun onImageShowing(settings: ReaderSettings) {
+	override fun onImageShowing(settings: ReaderSettings, isPreview: Boolean) {
 		with(binding.ssiv) {
 			maxScale = 2f * maxOf(
 				width / sWidth.toFloat(),

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

@@ -27,7 +27,7 @@ class ReversedPageHolder(
 			.gravity = Gravity.START or Gravity.BOTTOM
 	}
 
-	override fun onImageShowing(settings: ReaderSettings) {
+	override fun onImageShowing(settings: ReaderSettings, isPreview: Boolean) {
 		with(binding.ssiv) {
 			maxScale = 2f * maxOf(
 				width / sWidth.toFloat(),

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

@@ -89,11 +89,15 @@ open class PageHolder(
 		}
 	}
 
+	override fun onPreviewReady(source: ImageSource) {
+		binding.ssiv.setImage(source)
+	}
+
 	override fun onImageReady(source: ImageSource) {
 		binding.ssiv.setImage(source)
 	}
 
-	override fun onImageShowing(settings: ReaderSettings) {
+	override fun onImageShowing(settings: ReaderSettings, isPreview: Boolean) {
 		binding.ssiv.maxScale = 2f * maxOf(
 			binding.ssiv.width / binding.ssiv.sWidth.toFloat(),
 			binding.ssiv.height / binding.ssiv.sHeight.toFloat(),

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

@@ -89,11 +89,13 @@ class WebtoonHolder(
 		}
 	}
 
+	override fun onPreviewReady(source: ImageSource) = Unit
+
 	override fun onImageReady(source: ImageSource) {
 		binding.ssiv.setImage(source)
 	}
 
-	override fun onImageShowing(settings: ReaderSettings) {
+	override fun onImageShowing(settings: ReaderSettings, isPreview: Boolean) {
 		binding.ssiv.colorFilter = settings.colorFilter?.toColorFilter()
 		with(binding.ssiv) {
 			scrollTo(

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

@@ -11,7 +11,9 @@
 		android:layout_height="wrap_content"
 		android:layout_gravity="center"
 		android:indeterminate="true"
-		android:max="100" />
+		android:max="100"
+		app:hideAnimationBehavior="escape"
+		app:showAnimationBehavior="outward" />
 
 	<LinearLayout
 		android:id="@+id/layout_error"

gradle/libs.versions.toml

@@ -31,11 +31,11 @@ material = "1.13.0-alpha11"
 moshi = "1.15.2"
 okhttp = "4.12.0"
 okio = "3.10.2"
-parsers = "bebc615376"
+parsers = "5fa7590550"
 preference = "1.2.1"
 recyclerview = "1.4.0"
 room = "2.6.1"
-ssiv = "ba48c29803"
+ssiv = "9a67b6a7c9"
 swiperefreshlayout = "1.1.0"
 testRules = "1.6.1"
 testRunner = "1.6.2"