Feat 为画廊模式添加每页显示图片数量的配置 (#82)

* Feat: Add dynamic image-per-page configuration for gallery mode

- Implemented a slider to configure the number of images displayed per page (1-5) in gallery mode.
- Updated the reader to dynamically reflect changes in the `imagesPerPage` setting without requiring a mode switch or reopening.
- Ensured compatibility with existing continuous reading mode.

* fix currentImagesPerPage

* fix Continuous mode

* improve readerScreenPicNumber setting disable view

* improve PhotoViewController

assets/translation.json

@@ -105,6 +105,7 @@
     "Continuous (Right to Left)": "连续（从右到左）",
     "Continuous (Top to Bottom)": "连续（从上到下）",
     "Auto page turning interval": "自动翻页间隔",
+    "The number of pic in screen (Only Gallery Mode)": "同屏幕图片数量(仅画廊模式)",
     "Theme Mode": "主题模式",
     "System": "系统",
     "Light": "浅色",
@@ -353,6 +354,7 @@
     "Continuous (Right to Left)": "連續（從右到左）",
     "Continuous (Top to Bottom)": "連續（從上到下）",
     "Auto page turning interval": "自動翻頁間隔",
+    "The number of pic in screen (Only Gallery Mode)": "同螢幕圖片數量(僅畫廊模式)",
     "Theme Mode": "主題模式",
     "System": "系統",
     "Light": "浅色",

lib/foundation/appdata.dart

@@ -106,6 +106,7 @@ class _Settings with ChangeNotifier {
     'defaultSearchTarget': null,
     'autoPageTurningInterval': 5, // in seconds
     'readerMode': 'galleryLeftToRight', // values of [ReaderMode]
+    'readerScreenPicNumber': 1, // 1 - 5
     'enableTapToTurnPages': true,
     'enablePageAnimation': true,
     'language': 'system', // system, zh-CN, zh-TW, en-US

lib/pages/reader/images.dart

@@ -83,7 +83,8 @@ class _ReaderImagesState extends State<_ReaderImages> {
       );
     } else {
       if (reader.mode.isGallery) {
-        return _GalleryMode(key: Key(reader.mode.key));
+        return _GalleryMode(
+            key: Key('${reader.mode.key}_${reader.imagesPerPage}'));
       } else {
         return _ContinuousMode(key: Key(reader.mode.key));
       }
@@ -110,6 +111,10 @@ class _GalleryModeState extends State<_GalleryMode>
 
   late _ReaderState reader;
 
+  int get totalPages => ((reader.images!.length + reader.imagesPerPage - 1) /
+          reader.imagesPerPage)
+      .ceil();
+
   @override
   void initState() {
     reader = context.reader;
@@ -124,8 +129,14 @@ class _GalleryModeState extends State<_GalleryMode>
 
   void cache(int current) {
     for (int i = current + 1; i <= current + preCacheCount; i++) {
-      if (i <= reader.maxPage && !cached[i]) {
+      if (i <= totalPages && !cached[i]) {
-        _precacheImage(i, context);
+        int startIndex = (i - 1) * reader.imagesPerPage;
+        int endIndex =
+            math.min(startIndex + reader.imagesPerPage, reader.images!.length);
+        for (int i = startIndex; i < endIndex; i++) {
+          precacheImage(
+              _createImageProviderFromKey(reader.images![i], context), context);
+        }
         cached[i] = true;
       }
     }
@@ -141,32 +152,34 @@ class _GalleryModeState extends State<_GalleryMode>
       scrollDirection: reader.mode == ReaderMode.galleryTopToBottom
           ? Axis.vertical
           : Axis.horizontal,
-      itemCount: reader.images!.length + 2,
+      itemCount: totalPages + 2,
       builder: (BuildContext context, int index) {
-        ImageProvider? imageProvider;
+        if (index == 0 || index == totalPages + 1) {
-        if (index != 0 && index != reader.images!.length + 1) {
-          imageProvider = _createImageProvider(index, context);
-        } else {
           return PhotoViewGalleryPageOptions.customChild(
             scaleStateController: PhotoViewScaleStateController(),
             child: const SizedBox(),
           );
+        } else {
+          int pageIndex = index - 1;
+          int startIndex = pageIndex * reader.imagesPerPage;
+          int endIndex = math.min(startIndex + reader.imagesPerPage, reader.images!.length);
+          List<String> pageImages = reader.images!.sublist(startIndex, endIndex);
+
+          cached[index] = true;
+          cache(index);
+
+          photoViewControllers[index] = PhotoViewController();
+
+          return PhotoViewGalleryPageOptions.customChild(
+            child: PhotoView.customChild(
+              key: ValueKey('photo_view_$index'),
+              controller: photoViewControllers[index],
+              minScale: PhotoViewComputedScale.contained * 1.0,
+              maxScale: PhotoViewComputedScale.covered * 10.0,
+              child: buildPageImages(pageImages),
+            ),
+          );
         }
-
-        cached[index] = true;
-        cache(index);
-
-        photoViewControllers[index] ??= PhotoViewController();
-
-        return PhotoViewGalleryPageOptions(
-          filterQuality: FilterQuality.medium,
-          controller: photoViewControllers[index],
-          imageProvider: imageProvider,
-          fit: BoxFit.contain,
-          errorBuilder: (_, error, s, retry) {
-            return NetworkError(message: error.toString(), retry: retry);
-          },
-        );
       },
       pageController: controller,
       loadingBuilder: (context, event) => Center(
@@ -186,9 +199,9 @@ class _GalleryModeState extends State<_GalleryMode>
           if (!reader.toPrevChapter()) {
             reader.toPage(1);
           }
-        } else if (i == reader.maxPage + 1) {
+        } else if (i == totalPages + 1) {
           if (!reader.toNextChapter()) {
-            reader.toPage(reader.maxPage);
+            reader.toPage(totalPages);
           }
         } else {
           reader.setPage(i);
@@ -198,9 +211,30 @@ class _GalleryModeState extends State<_GalleryMode>
     );
   }
 
+  Widget buildPageImages(List<String> images) {
+    Axis axis = (reader.mode == ReaderMode.galleryTopToBottom)
+        ? Axis.vertical
+        : Axis.horizontal;
+
+    List<Widget> imageWidgets = images.map((imageKey) {
+      ImageProvider imageProvider =
+          _createImageProviderFromKey(imageKey, context);
+      return Expanded(
+        child: Image(
+          image: imageProvider,
+          fit: BoxFit.contain,
+        ),
+      );
+    }).toList();
+
+    return axis == Axis.vertical
+        ? Column(children: imageWidgets)
+        : Row(children: imageWidgets);
+  }
+
   @override
   Future<void> animateToPage(int page) {
-    if ((page - controller.page!).abs() > 1) {
+    if ((page - controller.page!.round()).abs() > 1) {
       controller.jumpToPage(page > controller.page! ? page - 1 : page + 1);
     }
     return controller.animateToPage(
@@ -600,6 +634,21 @@ class _ContinuousModeState extends State<_ContinuousMode>
   }
 }
 
+ImageProvider _createImageProviderFromKey(
+    String imageKey, BuildContext context) {
+  if (imageKey.startsWith('file://')) {
+    return FileImage(File(imageKey.replaceFirst("file://", '')));
+  } else {
+    var reader = context.reader;
+    return ReaderImageProvider(
+      imageKey,
+      reader.type.comicSource!.key,
+      reader.cid,
+      reader.eid,
+    );
+  }
+}
+
 ImageProvider _createImageProvider(int page, BuildContext context) {
   var reader = context.reader;
   var imageKey = reader.images![page - 1];

lib/pages/reader/reader.dart

@@ -1,6 +1,7 @@
 library venera_reader;
 
 import 'dart:async';
+import 'dart:math' as math;
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
@@ -82,7 +83,8 @@ class _ReaderState extends State<Reader> with _ReaderLocation, _ReaderWindow {
   }
 
   @override
-  int get maxPage => images?.length ?? 1;
+  int get maxPage =>
+      ((images?.length ?? 1) + imagesPerPage - 1) ~/ imagesPerPage;
 
   ComicType get type => widget.type;
 
@@ -94,6 +96,30 @@ class _ReaderState extends State<Reader> with _ReaderLocation, _ReaderWindow {
 
   late ReaderMode mode;
 
+  int get imagesPerPage => appdata.settings['readerScreenPicNumber'] ?? 1;
+
+  int _lastImagesPerPage = appdata.settings['readerScreenPicNumber'] ?? 1;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    _checkImagesPerPageChange();
+  }
+
+  void _checkImagesPerPageChange() {
+    int currentImagesPerPage = imagesPerPage;
+    if (_lastImagesPerPage != currentImagesPerPage) {
+      _adjustPageForImagesPerPageChange(_lastImagesPerPage, currentImagesPerPage);
+      _lastImagesPerPage = currentImagesPerPage;
+    }
+  }
+
+  void _adjustPageForImagesPerPageChange(int oldImagesPerPage, int newImagesPerPage) {
+    int previousImageIndex = (page - 1) * oldImagesPerPage;
+    int newPage = (previousImageIndex ~/ newImagesPerPage) + 1;
+    page = newPage;
+  }
+
   History? history;
 
   @override
@@ -133,6 +159,7 @@ class _ReaderState extends State<Reader> with _ReaderLocation, _ReaderWindow {
 
   @override
   Widget build(BuildContext context) {
+    _checkImagesPerPageChange();
     return KeyboardListener(
       focusNode: focusNode,
       autofocus: true,

lib/pages/settings/reader.dart

@@ -41,6 +41,11 @@ class _ReaderSettingsState extends State<ReaderSettings> {
             "continuousTopToBottom": "Continuous (Top to Bottom)".tl,
           },
           onChanged: () {
+            var readerMode = appdata.settings['readerMode'];
+            if (readerMode?.toLowerCase().startsWith('continuous') ?? false) {
+              appdata.settings['readerScreenPicNumber'] = 1;
+              widget.onChanged?.call('readerScreenPicNumber');
+            }
             widget.onChanged?.call("readerMode");
           },
         ).toSliver(),
@@ -54,6 +59,25 @@ class _ReaderSettingsState extends State<ReaderSettings> {
             widget.onChanged?.call("autoPageTurningInterval");
           },
         ).toSliver(),
+        SliverToBoxAdapter(
+          child: AbsorbPointer(
+            absorbing: (appdata.settings['readerMode']?.toLowerCase().startsWith('continuous') ?? false),
+            child: AnimatedOpacity(
+              opacity: (appdata.settings['readerMode']?.toLowerCase().startsWith('continuous') ?? false) ? 0.5 : 1.0,
+              duration: Duration(milliseconds: 300),
+              child: _SliderSetting(
+                title: "The number of pic in screen (Only Gallery Mode)".tl,
+                settingsIndex: "readerScreenPicNumber",
+                interval: 1,
+                min: 1,
+                max: 5,
+                onChanged: () {
+                  widget.onChanged?.call("readerScreenPicNumber");
+                },
+              ),
+            ),
+          ),
+        ),
         _SwitchSetting(
           title: 'Long press to zoom'.tl,
           settingKey: 'enableLongPressToZoom',