fix #107

lib/components/code.dart

@@ -0,0 +1,96 @@
+part of 'components.dart';
+
+class CodeEditor extends StatefulWidget {
+  const CodeEditor({super.key, this.initialValue, this.onChanged});
+
+  final String? initialValue;
+
+  final void Function(String value)? onChanged;
+
+  @override
+  State<CodeEditor> createState() => _CodeEditorState();
+}
+
+class _CodeEditorState extends State<CodeEditor> {
+  late TextEditingController _controller;
+  late FocusNode _focusNode;
+  var horizontalScrollController = ScrollController();
+  var verticalScrollController = ScrollController();
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = TextEditingController(text: widget.initialValue);
+    _focusNode = FocusNode()
+      ..onKeyEvent = (node, event) {
+        if (event.logicalKey == LogicalKeyboardKey.tab) {
+          if (event is KeyDownEvent) {
+            handleTab();
+          }
+          return KeyEventResult.handled;
+        }
+        return KeyEventResult.ignored;
+      };
+  }
+
+  void handleTab() {
+    var text = _controller.text;
+    var start = _controller.selection.start;
+    var end = _controller.selection.end;
+    _controller.text = '${text.substring(0, start)}    ${text.substring(end)}';
+    _controller.selection = TextSelection.collapsed(offset: start + 4);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scrollbar(
+      thumbVisibility: true,
+      controller: verticalScrollController,
+      notificationPredicate: (notif) => notif.metrics.axis == Axis.vertical,
+      child: Scrollbar(
+        thumbVisibility: true,
+        controller: horizontalScrollController,
+        notificationPredicate: (notif) => notif.metrics.axis == Axis.horizontal,
+        child: SizedBox.expand(
+          child: ScrollConfiguration(
+            behavior: _CustomScrollBehavior(),
+            child: SingleChildScrollView(
+              scrollDirection: Axis.horizontal,
+              controller: horizontalScrollController,
+              child: IntrinsicWidth(
+                stepWidth: 100,
+                child: TextField(
+                  style: TextStyle(
+                    fontFamily: 'consolas',
+                    fontFamilyFallback: ['Courier New', 'monospace'],
+                  ),
+                  controller: _controller,
+                  focusNode: _focusNode,
+                  maxLines: null,
+                  expands: true,
+                  decoration: InputDecoration(
+                    border: InputBorder.none,
+                    contentPadding: EdgeInsets.all(8),
+                  ),
+                  onChanged: (value) {
+                    widget.onChanged?.call(value);
+                  },
+                  scrollController: verticalScrollController,
+                ),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+class _CustomScrollBehavior extends MaterialScrollBehavior {
+  const _CustomScrollBehavior();
+  @override
+  Widget buildScrollbar(
+      BuildContext context, Widget child, ScrollableDetails details) {
+    return child;
+  }
+}

lib/components/components.dart

@@ -44,4 +44,5 @@ part 'select.dart';
 part 'side_bar.dart';
 part 'comic.dart';
 part 'effects.dart';
-part 'gesture.dart';
+part 'gesture.dart';
+part 'code.dart';

lib/components/pop_up_widget.dart

@@ -155,6 +155,9 @@ class _PopUpWidgetScaffoldState extends State<PopUpWidgetScaffold> {
           ),
           NotificationListener<ScrollNotification>(
             onNotification: (notifications) {
+              if (notifications.metrics.axisDirection != AxisDirection.down) {
+                return false;
+              }
               if (notifications.metrics.pixels ==
                       notifications.metrics.minScrollExtent &&
                   !top) {

lib/foundation/appdata.dart

@@ -13,7 +13,7 @@ class _Appdata {
 
   bool _isSavingData = false;
 
-  Future<void> saveData() async {
+  Future<void> saveData([bool sync = true]) async {
     if (_isSavingData) {
       await Future.doWhile(() async {
         await Future.delayed(const Duration(milliseconds: 20));
@@ -25,7 +25,9 @@ class _Appdata {
     var file = File(FilePath.join(App.dataPath, 'appdata.json'));
     await file.writeAsString(data);
     _isSavingData = false;
-    DataSync().uploadData();
+    if (sync) {
+      DataSync().uploadData();
+    }
   }
 
   void addSearchHistory(String keyword) {
@@ -78,6 +80,25 @@ class _Appdata {
     };
   }
 
+  /// Following fields are related to device-specific data and should not be synced.
+  static const _disableSync = [
+    "proxy",
+    "authorizationRequired",
+    "customImageProcessing",
+  ];
+
+  /// Sync data from another device
+  void syncData(Map<String, dynamic> data) {
+    for (var key in data.keys) {
+      if (_disableSync.contains(key)) {
+        continue;
+      }
+      settings[key] = data[key];
+    }
+    searchHistory = List.from(data['searchHistory']);
+    saveData();
+  }
+
   var implicitData = <String, dynamic>{};
 
   void writeImplicitData() {
@@ -126,6 +147,8 @@ class _Settings with ChangeNotifier {
     'onClickFavorite': 'viewDetail', // viewDetail, read
     'enableDnsOverrides': false,
     'dnsOverrides': {},
+    'enableCustomImageProcessing': false,
+    'customImageProcessing': _defaultCustomImageProcessing,
   };
 
   operator [](String key) {
@@ -142,3 +165,16 @@ class _Settings with ChangeNotifier {
     return _data.toString();
   }
 }
+
+const _defaultCustomImageProcessing = '''
+/**
+ * Process an image
+ * @param image {ArayBuffer} - The image to process
+ * @param cid {string} - The comic ID
+ * @param eid {string} - The episode ID
+ * @returns {Promise<ArrayBuffer>} - The processed image
+ */
+async function processImage(image, cid, eid) {
+    return image;
+}
+''';

lib/foundation/image_provider/reader_image.dart

@@ -1,10 +1,13 @@
 import 'dart:async' show Future, StreamController;
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_qjs/flutter_qjs.dart';
+import 'package:venera/foundation/js_engine.dart';
 import 'package:venera/network/images.dart';
 import 'package:venera/utils/io.dart';
 import 'base_image_provider.dart';
 import 'reader_image.dart' as image_provider;
+import 'package:venera/foundation/appdata.dart';
 
 class ReaderImageProvider
     extends BaseImageProvider<image_provider.ReaderImageProvider> {
@@ -21,25 +24,50 @@ class ReaderImageProvider
 
   @override
   Future<Uint8List> load(StreamController<ImageChunkEvent> chunkEvents) async {
+    Uint8List? imageBytes;
     if (imageKey.startsWith('file://')) {
       var file = File(imageKey);
       if (await file.exists()) {
-        return file.readAsBytes();
+        imageBytes = await file.readAsBytes();
+      } else {
+        throw "Error: File not found.";
       }
-      throw "Error: File not found.";
-    }
-
-    await for (var event
+    } else {
+      await for (var event
         in ImageDownloader.loadComicImage(imageKey, sourceKey, cid, eid)) {
-      chunkEvents.add(ImageChunkEvent(
-        cumulativeBytesLoaded: event.currentBytes,
-        expectedTotalBytes: event.totalBytes,
-      ));
-      if (event.imageBytes != null) {
-        return event.imageBytes!;
+        chunkEvents.add(ImageChunkEvent(
+          cumulativeBytesLoaded: event.currentBytes,
+          expectedTotalBytes: event.totalBytes,
+        ));
+        if (event.imageBytes != null) {
+          imageBytes = event.imageBytes;
+          break;
+        }
       }
     }
-    throw "Error: Empty response body.";
+    if (imageBytes == null) {
+      throw "Error: Empty response body.";
+    }
+    if (appdata.settings['enableCustomImageProcessing']) {
+      var script = appdata.settings['customImageProcessing'].toString();
+      if (!script.contains('async function processImage')) {
+        return imageBytes;
+      }
+      var func = JsEngine().runCode('''
+        (() => {
+          $script
+          return processImage;
+        })()
+      ''');
+      if (func is JSInvokable) {
+        var result = await func.invoke([imageBytes, cid, eid]);
+        func.free();
+        if (result is Uint8List) {
+          return result;
+        }
+      }
+    }
+    return imageBytes;
   }
 
   @override

lib/pages/settings/reader.dart

@@ -61,9 +61,17 @@ class _ReaderSettingsState extends State<ReaderSettings> {
         ).toSliver(),
         SliverToBoxAdapter(
           child: AbsorbPointer(
-            absorbing: (appdata.settings['readerMode']?.toLowerCase().startsWith('continuous') ?? false),
+            absorbing: (appdata.settings['readerMode']
+                    ?.toLowerCase()
+                    .startsWith('continuous') ??
+                false),
             child: AnimatedOpacity(
-              opacity: (appdata.settings['readerMode']?.toLowerCase().startsWith('continuous') ?? false) ? 0.5 : 1.0,
+              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,
@@ -93,7 +101,7 @@ class _ReaderSettingsState extends State<ReaderSettings> {
             widget.onChanged?.call('limitImageWidth');
           },
         ).toSliver(),
-        if(App.isAndroid)
+        if (App.isAndroid)
           _SwitchSetting(
             title: 'Turn page by volume keys'.tl,
             settingKey: 'enableTurnPageByVolumeKey',
@@ -108,7 +116,67 @@ class _ReaderSettingsState extends State<ReaderSettings> {
             widget.onChanged?.call("enableClockAndBatteryInfoInReader");
           },
         ).toSliver(),
+        _PopupWindowSetting(
+          title: "Custom Image Processing".tl,
+          builder: () => _CustomImageProcessing(),
+        ).toSliver(),
       ],
     );
   }
 }
+
+class _CustomImageProcessing extends StatefulWidget {
+  const _CustomImageProcessing();
+
+  @override
+  State<_CustomImageProcessing> createState() => __CustomImageProcessingState();
+}
+
+class __CustomImageProcessingState extends State<_CustomImageProcessing> {
+  var current = '';
+
+  @override
+  void initState() {
+    super.initState();
+    current = appdata.settings['customImageProcessing'];
+  }
+
+  @override
+  void dispose() {
+    appdata.settings['customImageProcessing'] = current;
+    appdata.saveData();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return PopUpWidgetScaffold(
+      title: "Custom Image Processing".tl,
+      body: Column(
+        children: [
+          _SwitchSetting(
+            title: "Enable".tl,
+            settingKey: "enableCustomImageProcessing",
+          ),
+          Expanded(
+            child: Container(
+              margin: EdgeInsets.all(8),
+              decoration: BoxDecoration(
+                borderRadius: BorderRadius.circular(4),
+                border: Border.all(color: context.colorScheme.outlineVariant),
+              ),
+              child: SizedBox.expand(
+                child: CodeEditor(
+                  initialValue: appdata.settings['customImageProcessing'],
+                  onChanged: (value) {
+                    current = value;
+                  },
+                ),
+              ),
+            ),
+          )
+        ],
+      ),
+    );
+  }
+}

lib/utils/data.dart

@@ -80,15 +80,9 @@ Future<void> importAppData(File file, [bool checkVersion = false]) async {
       LocalFavoritesManager().init();
     }
     if (await appdataFile.exists()) {
-      // proxy settings & authorization setting should be kept
-      var proxySettings = appdata.settings["proxy"];
-      var authSettings = appdata.settings["authorizationRequired"];
-      File(FilePath.join(App.dataPath, "appdata.json")).deleteIfExistsSync();
-      appdataFile.renameSync(FilePath.join(App.dataPath, "appdata.json"));
-      await appdata.init();
-      appdata.settings["proxy"] = proxySettings;
-      appdata.settings["authorizationRequired"] = authSettings;
-      appdata.saveData();
+      var content = await appdataFile.readAsString();
+      var data = jsonDecode(content);
+      appdata.syncData(data);
     }
     if (await cookieFile.exists()) {
       SingleInstanceCookieJar.instance?.dispose();

lib/utils/data_sync.dart

@@ -99,7 +99,7 @@ class DataSync with ChangeNotifier {
 
       try {
         appdata.settings['dataVersion']++;
-        await appdata.saveData();
+        await appdata.saveData(false);
         var data = await exportAppData();
         var time =
             (DateTime.now().millisecondsSinceEpoch ~/ 86400000).toString();