feat: add BookOasis document reader and text settings

app/src/main/java/eu/kanade/presentation/reader/settings/ReaderSettingsDialog.kt

@@ -9,6 +9,7 @@ import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalView
 import androidx.compose.ui.window.DialogWindowProvider
@@ -29,13 +30,18 @@ fun ReaderSettingsDialog(
         stringResource(MR.strings.pref_category_reading_mode),
         stringResource(MR.strings.pref_category_general),
         stringResource(MR.strings.custom_filter),
+        stringResource(MR.strings.pref_category_text_reader),
     )
     val pagerState = rememberPagerState { tabTitles.size }
+    val initialTextStyle = remember { viewModel.preferences.textReaderStyle() }
 
     BoxWithConstraints {
         TabbedDialog(
             modifier = Modifier.heightIn(max = maxHeight * 0.75f),
             onDismissRequest = {
+                if (viewModel.preferences.textReaderStyle() != initialTextStyle) {
+                    viewModel.onTextSettingsChanged()
+                }
                 onDismissRequest()
                 onShowMenus()
             },
@@ -63,6 +69,7 @@ fun ReaderSettingsDialog(
                     0 -> ReadingModePage(viewModel)
                     1 -> GeneralPage(viewModel)
                     2 -> ColorFilterPage(viewModel)
+                    3 -> TextSettingsPage(viewModel)
                 }
             }
         }

app/src/main/java/eu/kanade/presentation/reader/settings/TextSettingsPage.kt

@@ -0,0 +1,83 @@
+package eu.kanade.presentation.reader.settings
+
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.FilterChip
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import eu.kanade.tachiyomi.ui.reader.setting.ReaderPreferences
+import eu.kanade.tachiyomi.ui.reader.setting.ReaderSettingsViewModel
+import tachiyomi.i18n.MR
+import tachiyomi.presentation.core.components.SettingsChipRow
+import tachiyomi.presentation.core.components.SliderItem
+import tachiyomi.presentation.core.i18n.stringResource
+import tachiyomi.presentation.core.util.collectAsState
+
+private val fontFamilies = listOf(
+    MR.strings.pref_text_reader_font_system to ReaderPreferences.TextFontFamily.SYSTEM,
+    MR.strings.pref_text_reader_font_sans to ReaderPreferences.TextFontFamily.SANS_SERIF,
+    MR.strings.pref_text_reader_font_serif to ReaderPreferences.TextFontFamily.SERIF,
+    MR.strings.pref_text_reader_font_mono to ReaderPreferences.TextFontFamily.MONOSPACE,
+)
+
+@Composable
+internal fun ColumnScope.TextSettingsPage(viewModel: ReaderSettingsViewModel) {
+    val fontSizePref = viewModel.preferences.textFontSize
+    val fontSize by fontSizePref.collectAsState()
+    SliderItem(
+        label = stringResource(MR.strings.pref_text_reader_font_size),
+        value = fontSize,
+        valueRange = 32..72,
+        steps = 19,
+        valueString = fontSize.toString(),
+        onChange = fontSizePref::set,
+        pillColor = MaterialTheme.colorScheme.surfaceContainerHighest,
+    )
+
+    val lineSpacingPref = viewModel.preferences.textLineSpacing
+    val lineSpacing by lineSpacingPref.collectAsState()
+    SliderItem(
+        label = stringResource(MR.strings.pref_text_reader_line_spacing),
+        value = lineSpacing,
+        valueRange = 90..180,
+        steps = 17,
+        valueString = "$lineSpacing%",
+        onChange = lineSpacingPref::set,
+        pillColor = MaterialTheme.colorScheme.surfaceContainerHighest,
+    )
+
+    val paragraphSpacingPref = viewModel.preferences.textParagraphSpacing
+    val paragraphSpacing by paragraphSpacingPref.collectAsState()
+    SliderItem(
+        label = stringResource(MR.strings.pref_text_reader_paragraph_spacing),
+        value = paragraphSpacing,
+        valueRange = 0..48,
+        steps = 11,
+        valueString = paragraphSpacing.toString(),
+        onChange = paragraphSpacingPref::set,
+        pillColor = MaterialTheme.colorScheme.surfaceContainerHighest,
+    )
+
+    val fontFamilyPref = viewModel.preferences.textFontFamily
+    val fontFamily by fontFamilyPref.collectAsState()
+    SettingsChipRow(MR.strings.pref_text_reader_font_family) {
+        fontFamilies.forEach { (label, value) ->
+            FilterChip(
+                selected = fontFamily == value,
+                onClick = { fontFamilyPref.set(value) },
+                label = { Text(stringResource(label)) },
+            )
+        }
+    }
+
+    Text(
+        text = stringResource(MR.strings.pref_text_reader_pdf_note),
+        style = MaterialTheme.typography.bodySmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+        modifier = Modifier.padding(horizontal = 24.dp, vertical = 12.dp),
+    )
+}

app/src/main/java/eu/kanade/tachiyomi/source/bookoasis/BookOasisCompat.kt

@@ -0,0 +1,131 @@
+package eu.kanade.tachiyomi.source.bookoasis
+
+import eu.kanade.tachiyomi.network.await
+import eu.kanade.tachiyomi.source.Source
+import eu.kanade.tachiyomi.source.model.SChapter
+import eu.kanade.tachiyomi.source.model.SManga
+import eu.kanade.tachiyomi.source.online.HttpSource
+import okhttp3.Request
+import org.json.JSONObject
+import java.net.URI
+import java.net.URLDecoder
+import java.nio.charset.StandardCharsets
+
+private const val BOOKOASIS_PACKAGE_PREFIX = "eu.kanade.tachiyomi.extension.all.bookoasis."
+private val SUPPORTED_FORMATS = setOf("zip", "cbz", "imgdir", "epub", "pdf", "txt")
+private val DOCUMENT_FORMATS = setOf("epub", "pdf", "txt")
+
+internal data class BookOasisChapterRef(
+    val bookId: Long,
+    val dbType: String,
+    val format: String,
+)
+
+internal fun Source.isBookOasisSource(): Boolean {
+    return this::class.java.name.startsWith(BOOKOASIS_PACKAGE_PREFIX)
+}
+
+internal fun String.toBookOasisChapterRef(): BookOasisChapterRef? {
+    val path = substringBefore('?')
+    val match = Regex("""^/api/media/books/(\d+)/info$""").matchEntire(path) ?: return null
+    val params = parseQueryParameters(this)
+    val format = params["bo_format"]?.lowercase() ?: return null
+    if (format !in DOCUMENT_FORMATS) return null
+
+    return BookOasisChapterRef(
+        bookId = match.groupValues[1].toLongOrNull() ?: return null,
+        dbType = params["type"].orEmpty().ifBlank { "general" },
+        format = format,
+    )
+}
+
+/**
+ * BookOasis extension v1.4.x filters its chapter list to ZIP/CBZ.
+ * Fetch the same detail JSON with the extension's authenticated client and
+ * rebuild the chapter list so EPUB/PDF/TXT remain visible to the host app.
+ */
+internal suspend fun HttpSource.fetchBookOasisChapters(manga: SManga): List<SChapter> {
+    val detailUrl = manga.url.toAbsoluteUrl(baseUrl)
+    val dbType = parseQueryParameters(detailUrl)["type"].orEmpty().ifBlank { "general" }
+
+    val request = Request.Builder()
+        .url(detailUrl)
+        .headers(headers)
+        .get()
+        .build()
+
+    val root = client.newCall(request).await().use { response ->
+        if (!response.isSuccessful) {
+            error("BookOasis detail request failed: HTTP ${response.code}")
+        }
+        JSONObject(response.body.string())
+    }
+
+    val rawBooks = root.optJSONArray("books") ?: return emptyList()
+    val books = buildList {
+        for (index in 0 until rawBooks.length()) {
+            val item = rawBooks.optJSONObject(index) ?: continue
+            val id = item.optLong("id", -1L)
+            val format = item.optString("file_format", "").lowercase()
+            if (id <= 0L || format !in SUPPORTED_FORMATS) continue
+
+            add(
+                Triple(
+                    id,
+                    item.optString("title", "").ifBlank { "Book $id" },
+                    format,
+                ),
+            )
+        }
+    }
+
+    return books.mapIndexed { index, (bookId, title, format) ->
+        SChapter.create().apply {
+            url = buildString {
+                append("/api/media/books/")
+                append(bookId)
+                append("/info?type=")
+                append(dbType)
+                if (format in DOCUMENT_FORMATS) {
+                    append("&bo_format=")
+                    append(format)
+                }
+            }
+            name = title
+            chapter_number = (books.size - index).toFloat()
+        }
+    }.reversed()
+}
+
+private fun String.toAbsoluteUrl(baseUrl: String): String {
+    return if (startsWith("http://") || startsWith("https://")) {
+        this
+    } else {
+        baseUrl.trimEnd('/') + "/" + trimStart('/')
+    }
+}
+
+private fun parseQueryParameters(urlOrPath: String): Map<String, String> {
+    val rawQuery = runCatching {
+        if (urlOrPath.startsWith("http://") || urlOrPath.startsWith("https://")) {
+            URI(urlOrPath).rawQuery
+        } else {
+            urlOrPath.substringAfter('?', "")
+        }
+    }.getOrDefault(urlOrPath.substringAfter('?', ""))
+
+    if (rawQuery.isNullOrBlank()) return emptyMap()
+
+    return rawQuery.split('&')
+        .mapNotNull { part ->
+            if (part.isBlank()) return@mapNotNull null
+            val key = part.substringBefore('=')
+            val value = part.substringAfter('=', "")
+            decodeQuery(key) to decodeQuery(value)
+        }
+        .toMap()
+}
+
+private fun decodeQuery(value: String): String {
+    return URLDecoder.decode(value, StandardCharsets.UTF_8.name())
+}

app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt

@@ -254,6 +254,7 @@ class ReaderActivity : BaseActivity() {
                 readerState = viewModel.state,
                 onChangeReadingMode = viewModel::setMangaReadingMode,
                 onChangeOrientation = viewModel::setMangaOrientationType,
+                onTextSettingsChanged = viewModel::reloadTextReaderStyle,
                 preferences = readerPreferences,
             )
         }

app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderViewModel.kt

@@ -90,6 +90,7 @@ import tachiyomi.domain.source.service.SourceManager
 import tachiyomi.source.local.image.LocalCoverManager
 import tachiyomi.source.local.isLocal
 import java.util.Date
+import kotlin.math.roundToInt
 import kotlin.time.Clock
 
 /**
@@ -326,7 +327,7 @@ class ReaderViewModel(
                 mutableState.update { it.copy(manga = manga, source = source) }
                 if (chapterId == -1L) chapterId = initialChapterId
 
-                loader = ChapterLoader(context, downloadManager, downloadProvider, chapterCache, manga, source)
+                loader = ChapterLoader(context, downloadManager, downloadProvider, chapterCache, manga, source, readerPreferences)
 
                 loadChapter(loader!!, chapterList.first { chapterId == it.chapter.id })
             } catch (e: Throwable) {
@@ -822,6 +823,31 @@ class ReaderViewModel(
         mutableState.update { it.copy(dialog = null) }
     }
 
+    fun reloadTextReaderStyle() {
+        val chapter = state.value.currentChapter ?: return
+        if (chapter.pageLoader?.usesTextReaderStyle != true) return
+        val chapterLoader = loader ?: return
+        val requestedPage = (state.value.currentPage - 1).coerceAtLeast(0)
+        val oldLastIndex = (chapter.pages?.lastIndex ?: 0).coerceAtLeast(0)
+        val readingProgress = if (oldLastIndex == 0) 0f else requestedPage.toFloat() / oldLastIndex
+
+        viewModelScope.launchIO {
+            try {
+                chapter.pageLoader?.recycle()
+                chapter.pageLoader = null
+                chapter.state = ReaderChapter.State.Wait
+                chapter.requestedPage = requestedPage
+                chapterLoader.loadChapter(chapter)
+                val newLastIndex = (chapter.pages?.lastIndex ?: 0).coerceAtLeast(0)
+                chapter.requestedPage = (readingProgress * newLastIndex).roundToInt().coerceIn(0, newLastIndex)
+                eventChannel.send(Event.ReloadViewerChapters)
+            } catch (e: Throwable) {
+                if (e is CancellationException) throw e
+                logcat(LogPriority.ERROR, e) { "Failed to reload text reader style" }
+            }
+        }
+    }
+
     fun setBrightnessOverlayValue(value: Int) {
         mutableState.update { it.copy(brightnessOverlayValue = value) }
     }

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/BookOasisFilePageLoader.kt

@@ -0,0 +1,110 @@
+package eu.kanade.tachiyomi.ui.reader.loader
+
+import android.content.Context
+import com.hippo.unifile.UniFile
+import eu.kanade.tachiyomi.network.await
+import eu.kanade.tachiyomi.source.bookoasis.BookOasisChapterRef
+import eu.kanade.tachiyomi.source.online.HttpSource
+import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
+import eu.kanade.tachiyomi.ui.reader.setting.TextReaderStyle
+import mihon.core.archive.epubReader
+import okhttp3.Request
+import java.io.File
+import java.io.IOException
+
+/**
+ * Opens BookOasis EPUB/PDF/TXT as native Mihon reader pages.
+ */
+internal class BookOasisFilePageLoader(
+    private val context: Context,
+    private val source: HttpSource,
+    private val ref: BookOasisChapterRef,
+    private val textStyle: TextReaderStyle,
+) : PageLoader() {
+
+    override var isLocal: Boolean = true
+    override val usesTextReaderStyle: Boolean = ref.format == "epub" || ref.format == "txt"
+
+    private var delegate: PageLoader? = null
+
+    override suspend fun getPages(): List<ReaderPage> {
+        check(!isRecycled)
+
+        val file = getOrDownloadFile()
+        val uniFile = UniFile.fromFile(file)
+            ?: error("Unable to open cached BookOasis file: ${file.absolutePath}")
+        val loader = when (ref.format) {
+            "epub" -> EpubPageLoader(uniFile.epubReader(context), textStyle)
+            "pdf" -> PdfPageLoader(context, uniFile)
+            "txt" -> TextPageLoader(uniFile, textStyle)
+            else -> error("Unsupported BookOasis document format: ${ref.format}")
+        }
+
+        delegate = loader
+        return loader.getPages()
+    }
+
+    override suspend fun loadPage(page: ReaderPage) {
+        delegate?.loadPage(page)
+    }
+
+    override fun retryPage(page: ReaderPage) {
+        delegate?.retryPage(page)
+    }
+
+    override fun recycle() {
+        delegate?.recycle()
+        delegate = null
+        super.recycle()
+    }
+
+    private suspend fun getOrDownloadFile(): File {
+        val cacheDir = File(context.cacheDir, "bookoasis_reader").apply { mkdirs() }
+        val target = File(cacheDir, "${ref.dbType}-${ref.bookId}.${ref.format}")
+        if (target.isFile && target.length() > 0L) {
+            return target
+        }
+
+        val temp = File(cacheDir, "${target.name}.part")
+        if (temp.exists()) temp.delete()
+
+        val downloadUrl = buildString {
+            append(source.baseUrl.trimEnd('/'))
+            append("/api/media/books/")
+            append(ref.bookId)
+            append("/download?type=")
+            append(ref.dbType)
+        }
+
+        val request = Request.Builder()
+            .url(downloadUrl)
+            .headers(source.headers)
+            .get()
+            .build()
+
+        source.client.newCall(request).await().use { response ->
+            if (!response.isSuccessful) {
+                throw IOException(
+                    "BookOasis ${ref.format.uppercase()} download failed: HTTP ${response.code}",
+                )
+            }
+
+            temp.outputStream().use { output ->
+                response.body.byteStream().use { input ->
+                    input.copyTo(output)
+                }
+            }
+        }
+
+        if (temp.length() <= 0L) {
+            temp.delete()
+            throw IOException("BookOasis returned an empty ${ref.format.uppercase()} file")
+        }
+
+        if (!temp.renameTo(target)) {
+            temp.copyTo(target, overwrite = true)
+            temp.delete()
+        }
+        return target
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/ChapterLoader.kt

@@ -5,8 +5,11 @@ import eu.kanade.tachiyomi.data.cache.ChapterCache
 import eu.kanade.tachiyomi.data.download.DownloadManager
 import eu.kanade.tachiyomi.data.download.DownloadProvider
 import eu.kanade.tachiyomi.source.Source
+import eu.kanade.tachiyomi.source.bookoasis.isBookOasisSource
+import eu.kanade.tachiyomi.source.bookoasis.toBookOasisChapterRef
 import eu.kanade.tachiyomi.source.online.HttpSource
 import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
+import eu.kanade.tachiyomi.ui.reader.setting.ReaderPreferences
 import mihon.core.archive.archiveReader
 import mihon.core.archive.epubReader
 import tachiyomi.core.common.i18n.stringResource
@@ -28,6 +31,7 @@ class ChapterLoader(
     private val chapterCache: ChapterCache,
     private val manga: Manga,
     private val source: Source,
+    private val readerPreferences: ReaderPreferences,
 ) {
 
     /**
@@ -86,6 +90,8 @@ class ChapterLoader(
             manga.title,
             source,
         )
+        val bookOasisRef = dbChapter.url.toBookOasisChapterRef()
+
         return when {
             isDownloaded -> DownloadPageLoader(
                 chapter,
@@ -98,9 +104,14 @@ class ChapterLoader(
                 when (format) {
                     is Format.Directory -> DirectoryPageLoader(format.file)
                     is Format.Archive -> ArchivePageLoader(format.file.archiveReader(context))
-                    is Format.Epub -> EpubPageLoader(format.file.epubReader(context))
+                    is Format.Epub -> EpubPageLoader(format.file.epubReader(context), readerPreferences.textReaderStyle())
+                    is Format.Pdf -> PdfPageLoader(context, format.file)
+                    is Format.Text -> TextPageLoader(format.file, readerPreferences.textReaderStyle())
                 }
             }
+            source is HttpSource && source.isBookOasisSource() && bookOasisRef != null -> {
+                BookOasisFilePageLoader(context, source, bookOasisRef, readerPreferences.textReaderStyle())
+            }
             source is HttpSource -> HttpPageLoader(chapter, source, chapterCache)
             source is StubSource -> error(context.stringResource(MR.strings.source_not_installed, source.toString()))
             else -> error(context.stringResource(MR.strings.loader_not_implemented_error))

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/EpubPageLoader.kt

@@ -2,18 +2,39 @@ package eu.kanade.tachiyomi.ui.reader.loader
 
 import eu.kanade.tachiyomi.source.model.Page
 import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
+import eu.kanade.tachiyomi.ui.reader.setting.TextReaderStyle
 import mihon.core.archive.EpubReader
 
 /**
  * Loader used to load a chapter from a .epub file.
+ *
+ * Text-based EPUBs are rendered as regular Mihon pages. Image-only EPUBs
+ * keep the original image extraction behavior.
  */
-internal class EpubPageLoader(private val reader: EpubReader) : PageLoader() {
+internal class EpubPageLoader(
+    private val reader: EpubReader,
+    private val style: TextReaderStyle,
+) : PageLoader() {
 
     override var isLocal: Boolean = true
+    override val usesTextReaderStyle: Boolean = true
 
     override suspend fun getPages(): List<ReaderPage> {
-        return reader.getImagesFromPages().mapIndexed { i, path ->
+        val textPages = reader.getTextFromPages()
-            ReaderPage(i).apply {
+            .filter { it.isNotBlank() }
+            .flatMap { TextPageRenderer.paginate(it, style) }
+
+        if (textPages.isNotEmpty()) {
+            return textPages.mapIndexed { index, text ->
+                ReaderPage(index).apply {
+                    stream = { TextPageRenderer.render(text, style) }
+                    status = Page.State.Ready
+                }
+            }
+        }
+
+        return reader.getImagesFromPages().mapIndexed { index, path ->
+            ReaderPage(index).apply {
                 stream = { reader.getInputStream(path)!! }
                 status = Page.State.Ready
             }

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/PageLoader.kt

@@ -17,6 +17,8 @@ abstract class PageLoader {
 
     abstract var isLocal: Boolean
 
+    open val usesTextReaderStyle: Boolean = false
+
     /**
      * Returns the list of pages of a chapter.
      */

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/PdfPageLoader.kt

@@ -0,0 +1,63 @@
+package eu.kanade.tachiyomi.ui.reader.loader
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.Color
+import android.graphics.pdf.PdfRenderer
+import android.os.ParcelFileDescriptor
+import com.hippo.unifile.UniFile
+import eu.kanade.tachiyomi.source.model.Page
+import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.InputStream
+
+internal class PdfPageLoader(
+    context: Context,
+    file: UniFile,
+) : PageLoader() {
+
+    override var isLocal: Boolean = true
+
+    private val descriptor: ParcelFileDescriptor =
+        context.contentResolver.openFileDescriptor(file.uri, "r")
+            ?: error("Unable to open PDF: ${file.name}")
+    private val renderer = PdfRenderer(descriptor)
+    private val renderLock = Any()
+
+    override suspend fun getPages(): List<ReaderPage> {
+        return (0 until renderer.pageCount).map { index ->
+            ReaderPage(index).apply {
+                stream = { renderPage(index) }
+                status = Page.State.Ready
+            }
+        }
+    }
+
+    private fun renderPage(index: Int): InputStream = synchronized(renderLock) {
+        check(!isRecycled)
+        renderer.openPage(index).use { page ->
+            val scale = (1600f / page.width.coerceAtLeast(1)).coerceIn(1f, 2.5f)
+            val width = (page.width * scale).toInt().coerceAtLeast(1)
+            val height = (page.height * scale).toInt().coerceAtLeast(1)
+            val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
+            bitmap.eraseColor(Color.WHITE)
+            page.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY)
+
+            val output = ByteArrayOutputStream()
+            bitmap.compress(Bitmap.CompressFormat.PNG, 100, output)
+            bitmap.recycle()
+            ByteArrayInputStream(output.toByteArray())
+        }
+    }
+
+    override fun recycle() {
+        if (!isRecycled) {
+            synchronized(renderLock) {
+                renderer.close()
+                descriptor.close()
+            }
+        }
+        super.recycle()
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/TextPageLoader.kt

@@ -0,0 +1,51 @@
+package eu.kanade.tachiyomi.ui.reader.loader
+
+import com.hippo.unifile.UniFile
+import eu.kanade.tachiyomi.source.model.Page
+import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
+import eu.kanade.tachiyomi.ui.reader.setting.TextReaderStyle
+import java.nio.ByteBuffer
+import java.nio.charset.CharacterCodingException
+import java.nio.charset.Charset
+import java.nio.charset.CodingErrorAction
+import java.nio.charset.StandardCharsets
+
+internal class TextPageLoader(
+    private val file: UniFile,
+    private val style: TextReaderStyle,
+) : PageLoader() {
+
+    override var isLocal: Boolean = true
+    override val usesTextReaderStyle: Boolean = true
+
+    override suspend fun getPages(): List<ReaderPage> {
+        val bytes = file.openInputStream().use { it.readBytes() }
+        val text = decodeText(bytes)
+        return TextPageRenderer.paginate(text, style).mapIndexed { index, pageText ->
+            ReaderPage(index).apply {
+                stream = { TextPageRenderer.render(pageText, style) }
+                status = Page.State.Ready
+            }
+        }
+    }
+
+    private fun decodeText(bytes: ByteArray): String {
+        if (bytes.size >= 3 &&
+            bytes[0] == 0xEF.toByte() &&
+            bytes[1] == 0xBB.toByte() &&
+            bytes[2] == 0xBF.toByte()
+        ) {
+            return String(bytes, 3, bytes.size - 3, StandardCharsets.UTF_8)
+        }
+
+        return try {
+            StandardCharsets.UTF_8.newDecoder()
+                .onMalformedInput(CodingErrorAction.REPORT)
+                .onUnmappableCharacter(CodingErrorAction.REPORT)
+                .decode(ByteBuffer.wrap(bytes))
+                .toString()
+        } catch (_: CharacterCodingException) {
+            String(bytes, Charset.forName("MS949"))
+        }
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/TextPageRenderer.kt

@@ -0,0 +1,114 @@
+package eu.kanade.tachiyomi.ui.reader.loader
+
+import android.graphics.Bitmap
+import android.graphics.Canvas
+import android.graphics.Color
+import android.graphics.Paint
+import android.graphics.Typeface
+import android.text.Layout
+import android.text.Spannable
+import android.text.SpannableString
+import android.text.StaticLayout
+import android.text.TextPaint
+import android.text.style.LineHeightSpan
+import eu.kanade.tachiyomi.ui.reader.setting.TextReaderStyle
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.InputStream
+
+internal object TextPageRenderer {
+    private const val PAGE_WIDTH = 1440
+    private const val PAGE_HEIGHT = 2160
+    private const val MARGIN = 96
+    private const val CONTENT_WIDTH = PAGE_WIDTH - (MARGIN * 2)
+    private const val CONTENT_HEIGHT = PAGE_HEIGHT - (MARGIN * 2)
+
+    fun paginate(text: String, style: TextReaderStyle): List<String> {
+        if (text.isBlank()) return emptyList()
+
+        val layout = createLayout(text, style)
+        if (layout.lineCount == 0) return listOf(text)
+
+        val pages = mutableListOf<String>()
+        var startLine = 0
+        while (startLine < layout.lineCount) {
+            val startTop = layout.getLineTop(startLine)
+            var endLine = startLine
+            while (
+                endLine + 1 < layout.lineCount &&
+                layout.getLineBottom(endLine + 1) - startTop <= CONTENT_HEIGHT
+            ) {
+                endLine++
+            }
+
+            val start = layout.getLineStart(startLine)
+            val end = layout.getLineEnd(endLine).coerceAtLeast(start + 1).coerceAtMost(text.length)
+            text.substring(start, end).trim().takeIf { it.isNotEmpty() }?.let(pages::add)
+            startLine = endLine + 1
+        }
+        return pages.ifEmpty { listOf(text) }
+    }
+
+    fun render(text: String, style: TextReaderStyle): InputStream {
+        val bitmap = Bitmap.createBitmap(PAGE_WIDTH, PAGE_HEIGHT, Bitmap.Config.ARGB_8888)
+        val canvas = Canvas(bitmap)
+        canvas.drawColor(Color.WHITE)
+        canvas.save()
+        canvas.translate(MARGIN.toFloat(), MARGIN.toFloat())
+        createLayout(text, style).draw(canvas)
+        canvas.restore()
+
+        val output = ByteArrayOutputStream()
+        bitmap.compress(Bitmap.CompressFormat.PNG, 100, output)
+        bitmap.recycle()
+        return ByteArrayInputStream(output.toByteArray())
+    }
+
+    private fun createLayout(text: String, style: TextReaderStyle): StaticLayout {
+        val paint = TextPaint().apply {
+            isAntiAlias = true
+            color = Color.BLACK
+            textSize = style.fontSize.toFloat()
+            typeface = style.fontFamily.androidFamilyName
+                ?.let { Typeface.create(it, Typeface.NORMAL) }
+                ?: Typeface.DEFAULT
+        }
+        val styledText = addParagraphSpacing(text, style.paragraphSpacing)
+        return StaticLayout.Builder
+            .obtain(styledText, 0, styledText.length, paint, CONTENT_WIDTH)
+            .setAlignment(Layout.Alignment.ALIGN_NORMAL)
+            .setIncludePad(true)
+            .setLineSpacing(0f, style.lineSpacingPercent / 100f)
+            .build()
+    }
+
+    private fun addParagraphSpacing(text: String, spacing: Int): CharSequence {
+        if (spacing <= 0 || '\n' !in text) return text
+        val spannable = SpannableString(text)
+        text.forEachIndexed { index, char ->
+            if (char == '\n') {
+                spannable.setSpan(
+                    ParagraphSpacingSpan(spacing),
+                    index,
+                    (index + 1).coerceAtMost(text.length),
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE,
+                )
+            }
+        }
+        return spannable
+    }
+
+    private class ParagraphSpacingSpan(private val spacing: Int) : LineHeightSpan {
+        override fun chooseHeight(
+            text: CharSequence?,
+            start: Int,
+            end: Int,
+            spanstartv: Int,
+            v: Int,
+            fm: Paint.FontMetricsInt,
+        ) {
+            fm.descent += spacing
+            fm.bottom += spacing
+        }
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/reader/setting/ReaderPreferences.kt

@@ -108,6 +108,28 @@ class ReaderPreferences(
 
     val webtoonDisableZoomOut: Preference<Boolean> = preferenceStore.getBoolean("webtoon_disable_zoom_out", false)
 
+    // region Text reader
+
+    val textFontSize: Preference<Int> = preferenceStore.getInt("reader_text_font_size", 44)
+
+    val textLineSpacing: Preference<Int> = preferenceStore.getInt("reader_text_line_spacing", 115)
+
+    val textParagraphSpacing: Preference<Int> = preferenceStore.getInt("reader_text_paragraph_spacing", 12)
+
+    val textFontFamily: Preference<TextFontFamily> = preferenceStore.getEnum(
+        "reader_text_font_family",
+        TextFontFamily.SYSTEM,
+    )
+
+    fun textReaderStyle() = TextReaderStyle(
+        fontSize = textFontSize.get(),
+        lineSpacingPercent = textLineSpacing.get(),
+        paragraphSpacing = textParagraphSpacing.get(),
+        fontFamily = textFontFamily.get(),
+    )
+
+    // endregion
+
     // endregion
 
     // region Split two-page spread
@@ -217,6 +239,13 @@ class ReaderPreferences(
 
     // endregion
 
+    enum class TextFontFamily(val androidFamilyName: String?) {
+        SYSTEM(null),
+        SANS_SERIF("sans-serif"),
+        SERIF("serif"),
+        MONOSPACE("monospace"),
+    }
+
     enum class FlashColor {
         BLACK,
         WHITE,
@@ -342,3 +371,11 @@ class ReaderPreferences(
         }
     }
 }
+
+
+data class TextReaderStyle(
+    val fontSize: Int,
+    val lineSpacingPercent: Int,
+    val paragraphSpacing: Int,
+    val fontFamily: ReaderPreferences.TextFontFamily,
+)

app/src/main/java/eu/kanade/tachiyomi/ui/reader/setting/ReaderSettingsViewModel.kt

@@ -13,6 +13,7 @@ class ReaderSettingsViewModel(
     readerState: StateFlow<ReaderViewModel.State>,
     val onChangeReadingMode: (ReadingMode) -> Unit,
     val onChangeOrientation: (ReaderOrientation) -> Unit,
+    val onTextSettingsChanged: () -> Unit,
     val preferences: ReaderPreferences,
 ) : ViewModel() {
 

app/src/main/java/mihon/domain/source/interactor/UpdateMangaFromRemote.kt

@@ -8,7 +8,10 @@ import eu.kanade.domain.manga.model.toSManga
 import eu.kanade.tachiyomi.data.cache.CoverCache
 import eu.kanade.tachiyomi.data.download.DownloadManager
 import eu.kanade.tachiyomi.source.Source
+import eu.kanade.tachiyomi.source.bookoasis.fetchBookOasisChapters
+import eu.kanade.tachiyomi.source.bookoasis.isBookOasisSource
 import eu.kanade.tachiyomi.source.model.SManga
+import eu.kanade.tachiyomi.source.online.HttpSource
 import logcat.LogPriority
 import mihon.domain.source.models.RemoteMangaUpdate
 import tachiyomi.core.common.util.lang.withIOContext
@@ -70,8 +73,28 @@ class UpdateMangaFromRemote(
                 )
             }
             awaitUpdateFromSource(manga, update.manga, manualFetch)
+
+            val rawSourceChapters = if (
+                fetchChapters &&
+                source is HttpSource &&
+                source.isBookOasisSource()
+            ) {
+                try {
+                    withIOContext {
+                        source.fetchBookOasisChapters(manga.toSManga())
+                    }
+                } catch (e: Exception) {
+                    logcat(LogPriority.ERROR, e) {
+                        "BookOasis document chapter compatibility fallback failed"
+                    }
+                    update.chapters
+                }
+            } else {
+                update.chapters
+            }
+
             val newChapters = syncChaptersWithSource.await(
-                rawSourceChapters = update.chapters,
+                rawSourceChapters = rawSourceChapters,
                 manga = manga,
                 source = source,
                 manualFetch = manualFetch,

core/archive/src/main/kotlin/mihon/core/archive/EpubReader.kt

@@ -34,6 +34,27 @@ class EpubReader(private val reader: ArchiveReader) : Closeable by reader {
         return getImagesFromPages(pages, ref)
     }
 
+    /**
+     * Returns readable text for each spine document in reading order.
+     */
+    fun getTextFromPages(): List<String> {
+        val ref = getPackageHref()
+        val doc = getPackageDocument(ref)
+        val basePath = getParentDirectory(ref)
+        return getPagesFromDocument(doc).mapNotNull { page ->
+            val entryPath = resolveZipPath(basePath, page)
+            getInputStream(entryPath)?.use { input ->
+                val pageDoc = Jsoup.parse(input, null, "")
+                pageDoc.select("br").append("\n")
+                pageDoc.select("p,div,li,h1,h2,h3,h4,h5,h6,blockquote").append("\n")
+                pageDoc.body()?.wholeText()
+                    ?.replace(Regex("[ \\t]+\\n"), "\n")
+                    ?.replace(Regex("\\n{3,}"), "\n\n")
+                    ?.trim()
+            }
+        }
+    }
+
     /**
      * Returns the path to the package document.
      */

i18n/src/commonMain/moko-resources/base/strings.xml

@@ -1099,4 +1099,16 @@
     <string name="donationCampaign.paragraph3">Regardless, Mihon will continue to be maintained by me and the volunteers, and it will stay open source.</string>
     <string name="donationCampaign.contactPlatform">Discord</string>
     <string name="donationCampaign.dismiss">Dismiss</string>
+
+    <!-- Text reader -->
+    <string name="pref_category_text_reader">Text</string>
+    <string name="pref_text_reader_font_size">Font size</string>
+    <string name="pref_text_reader_line_spacing">Line spacing</string>
+    <string name="pref_text_reader_paragraph_spacing">Paragraph spacing</string>
+    <string name="pref_text_reader_font_family">Font</string>
+    <string name="pref_text_reader_font_system">System</string>
+    <string name="pref_text_reader_font_sans">Sans-serif</string>
+    <string name="pref_text_reader_font_serif">Serif</string>
+    <string name="pref_text_reader_font_mono">Monospace</string>
+    <string name="pref_text_reader_pdf_note">EPUB and TXT use these typography settings. PDF keeps its original page layout.</string>
 </resources>

i18n/src/commonMain/moko-resources/ko/strings.xml

@@ -907,4 +907,16 @@
     <string name="pref_apply_content_warnings_to_installed_summary">비활성화하면 이미 설치한 확장 앱은 등급과 무관하게 컨텐츠를 불러오고 업데이트합니다</string>
     <string name="content_warnings_info">허용하지 않은 등급의 확장 앱은 이미 설치된 경우 목록에 남지만 소스는 표시되지 않으며, 설치하지 않은 경우 목록에서 숨겨집니다. 이 설정으로도 비공식 확장 앱이나 등급이 잘못 지정된 확장 앱이 앱에 18+ 콘텐츠를 표시하는 것을 완전히 막을 수는 없습니다.</string>
     <string name="ext_filtered">필터링됨</string>
+
+    <!-- Text reader -->
+    <string name="pref_category_text_reader">텍스트</string>
+    <string name="pref_text_reader_font_size">글자 크기</string>
+    <string name="pref_text_reader_line_spacing">행간</string>
+    <string name="pref_text_reader_paragraph_spacing">문단 간격</string>
+    <string name="pref_text_reader_font_family">글꼴</string>
+    <string name="pref_text_reader_font_system">시스템</string>
+    <string name="pref_text_reader_font_sans">고딕</string>
+    <string name="pref_text_reader_font_serif">명조</string>
+    <string name="pref_text_reader_font_mono">고정폭</string>
+    <string name="pref_text_reader_pdf_note">EPUB/TXT에는 이 글꼴 설정이 적용됩니다. PDF는 원본 페이지 레이아웃을 유지합니다.</string>
 </resources>

source-local/src/main/kotlin/tachiyomi/source/local/LocalSource.kt

@@ -290,7 +290,13 @@ class LocalSource(
         val chapters = fileSystem.getFilesInMangaDirectory(manga.url)
             // Only keep supported formats
             .filterNot { it.name.orEmpty().startsWith('.') }
-            .filter { it.isDirectory || Archive.isSupported(it) || it.extension.equals("epub", true) }
+            .filter {
+                it.isDirectory ||
+                    Archive.isSupported(it) ||
+                    it.extension.equals("epub", true) ||
+                    it.extension.equals("pdf", true) ||
+                    it.extension.equals("txt", true)
+            }
             .map { chapterFile ->
                 SChapter.create().apply {
                     url = "${manga.url}/${chapterFile.name}"
@@ -385,6 +391,9 @@ class LocalSource(
                         entry?.let { coverManager.update(manga, epub.getInputStream(it)!!) }
                     }
                 }
+                is Format.Pdf,
+                is Format.Text,
+                -> null
             }
         } catch (e: Throwable) {
             logcat(LogPriority.ERROR, e) { "Error updating cover for ${manga.title}" }

source-local/src/main/kotlin/tachiyomi/source/local/io/Format.kt

@@ -8,6 +8,8 @@ sealed interface Format {
     data class Directory(val file: UniFile) : Format
     data class Archive(val file: UniFile) : Format
     data class Epub(val file: UniFile) : Format
+    data class Pdf(val file: UniFile) : Format
+    data class Text(val file: UniFile) : Format
 
     class UnknownFormatException : Exception()
 
@@ -16,6 +18,8 @@ sealed interface Format {
         fun valueOf(file: UniFile) = when {
             file.isDirectory -> Directory(file)
             file.extension.equals("epub", true) -> Epub(file)
+            file.extension.equals("pdf", true) -> Pdf(file)
+            file.extension.equals("txt", true) -> Text(file)
             isArchiveSupported(file) -> Archive(file)
             else -> throw UnknownFormatException()
         }