Added showing a page overlay while reading a comic [#149]

androidVariant/src/main/java/org/comixedproject/variant/android/view/reading/PageNavigationView.kt

@@ -0,0 +1,227 @@
+/*
+ * Variant - A digital comic book reading application for the iPad and Android tablets.
+ * Copyright (C) 2025, The ComiXed Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses>
+ */
+
+package org.comixedproject.variant.android.view.reading
+
+import android.graphics.BitmapFactory
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Slider
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.tooling.preview.Preview
+import org.comixedproject.variant.adaptor.ArchiveAPI
+import org.comixedproject.variant.android.COMIC_BOOK_LIST
+import org.comixedproject.variant.android.R
+import org.comixedproject.variant.android.VariantTheme
+import org.comixedproject.variant.model.library.ComicBook
+import org.comixedproject.variant.platform.Log
+
+private const val TAG = "PageNavigationView"
+
+@Composable
+fun PageNavigationView(
+    comicBook: ComicBook,
+    onStopReading: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    var pageFilename by remember { mutableStateOf("") }
+    var currentPage by remember { mutableIntStateOf(0) }
+    var currentPageContent by remember { mutableStateOf<ByteArray?>(null) }
+    var showPageOverlay by remember { mutableStateOf(false) }
+    val context = LocalContext.current
+
+    Column(
+        modifier = modifier
+            .verticalScroll(rememberScrollState())
+            .pointerInput(Unit) {
+                detectTapGestures(
+                    onPress = { location ->
+                        var handled = false
+                        val screenHeightMiddle = context.resources.displayMetrics.heightPixels / 2
+                        if (location.y > (screenHeightMiddle * 1.5)) {
+                            val screenWidthMiddle = context.resources.displayMetrics.widthPixels / 2
+                            if (location.x <= (screenWidthMiddle / 2)) {
+                                if (currentPage > 0) {
+                                    Log.info(TAG, "Navigating back to page ${currentPage - 1}")
+                                    currentPageContent = null
+                                    currentPage = currentPage - 1
+                                }
+                                handled = true
+                            } else if (location.x >= (screenWidthMiddle * 3) / 2) {
+                                if (currentPage < comicBook.pages.size - 1) {
+                                    Log.info(
+                                        TAG,
+                                        "Navigating forward to page ${currentPage + 1}"
+                                    )
+                                    currentPageContent = null
+                                    currentPage = currentPage + 1
+                                }
+                                handled = true
+                            }
+                        }
+                        if (!handled) {
+                            showPageOverlay = (showPageOverlay == false)
+                            Log.info(TAG, "Setting show overlay: ${showPageOverlay}")
+                        }
+                    }
+                )
+            }
+            .fillMaxSize()) {
+        if (showPageOverlay) {
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                IconButton(
+                    onClick = {
+                        Log.debug(
+                            TAG,
+                            "Closing comic book"
+                        )
+                        onStopReading()
+                    }
+                ) {
+                    Icon(
+                        painterResource(R.drawable.ic_close),
+                        contentDescription = stringResource(R.string.stopReadingLabel)
+                    )
+                }
+
+                Text(
+                    text = comicBook.filename,
+                    style = MaterialTheme.typography.titleMedium,
+                    textAlign = TextAlign.Center,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier.fillMaxWidth()
+                )
+            }
+
+            Text(
+                text = pageFilename,
+                style = MaterialTheme.typography.titleSmall,
+                textAlign = TextAlign.Center,
+                maxLines = 1, overflow = TextOverflow.Ellipsis,
+                modifier = Modifier.fillMaxWidth()
+            )
+            Row(modifier = Modifier.fillMaxWidth()) {
+                IconButton(onClick = {
+                    currentPageContent = null
+                    currentPage = currentPage - 1
+                }, enabled = (currentPage > 0)) {
+                    Icon(
+                        painterResource(R.drawable.ic_previous_page),
+                        contentDescription = stringResource(R.string.previousPageLabel)
+                    )
+                }
+
+                Slider(
+                    value = currentPage.toFloat(),
+                    valueRange = 0f..(comicBook.pages.size - 1).toFloat(),
+                    steps = comicBook.pages.size,
+                    onValueChange = {
+                        currentPageContent = null
+                        currentPage = it.toInt()
+                    },
+                    modifier = Modifier.weight(0.9f)
+                )
+
+                IconButton(onClick = {
+                    currentPageContent = null
+                    currentPage = currentPage + 1
+                }, enabled = (currentPage < (comicBook.pages.size - 1))) {
+                    Icon(
+                        painterResource(R.drawable.ic_next_page),
+                        contentDescription = stringResource(R.string.nextPageLabel)
+                    )
+                }
+            }
+        }
+
+
+        if (currentPageContent == null) {
+            LaunchedEffect(currentPageContent) {
+                pageFilename = comicBook.pages.get(currentPage).filename
+                currentPageContent =
+                    ArchiveAPI.loadPage(comicBook.path, pageFilename)
+
+            }
+        } else {
+            currentPageContent?.let { content ->
+                Image(
+                    bitmap = BitmapFactory.decodeByteArray(content, 0, content.size)
+                        .asImageBitmap(),
+                    contentDescription = comicBook.pages.get(currentPage).filename,
+                    modifier = modifier
+                        .fillMaxHeight()
+                )
+            }
+        }
+    }
+}
+
+
+@Composable
+@Preview
+fun PageNavigationPreview() {
+    val comic = COMIC_BOOK_LIST.get(0)
+
+    VariantTheme {
+        PageNavigationView(
+            comic,
+            onStopReading = {})
+    }
+}
+
+@Composable
+@Preview
+fun PageNavigationPreviewWithOverlay() {
+    val comic = COMIC_BOOK_LIST.get(0)
+
+    VariantTheme {
+        PageNavigationView(
+            comic,
+            onStopReading = {})
+    }
+}