Add image cropping functionality with isolate support and optimize crop border processing

lib/main.dart

@@ -22,6 +22,7 @@ import 'package:mangayomi/models/track.dart' as track;
 import 'package:mangayomi/models/track_preference.dart';
 import 'package:mangayomi/models/track_search.dart';
 import 'package:mangayomi/modules/manga/detail/providers/track_state_providers.dart';
+import 'package:mangayomi/modules/manga/reader/providers/crop_borders_provider.dart';
 import 'package:mangayomi/modules/more/data_and_storage/providers/storage_usage.dart';
 import 'package:mangayomi/modules/more/settings/browse/providers/browse_state_provider.dart';
 import 'package:mangayomi/modules/more/settings/general/providers/general_state_provider.dart';
@@ -52,6 +53,7 @@ void main(List<String> args) async {
   if (Platform.isLinux && runWebViewTitleBarWidget(args)) return;
   MediaKit.ensureInitialized();
   await RustLib.init();
+  await imgCropIsolate.start();
   if (!(Platform.isAndroid || Platform.isIOS)) {
     await windowManager.ensureInitialized();
   }

lib/modules/manga/reader/providers/crop_borders_provider.dart

@@ -23,12 +23,119 @@ Future<Uint8List?> cropBorders(
       return null;
     }
 
-    return await Isolate.run(() async {
-      await RustLib.init();
-      final imageRes = processCropImage(image: imageBytes!);
-      RustLib.dispose();
-      return imageRes;
-    });
+    return imgCropIsolate.process(imageBytes);
   }
   return null;
 }
+
+class ImageCropIsolate {
+  bool _isRunning = false;
+  Isolate? _rustIsolate;
+  ReceivePort? _receivePort;
+  SendPort? _sendPort;
+
+  Future<void> start() async {
+    if (!_isRunning) {
+      try {
+        await _initRustIsolate();
+      } catch (_) {
+        await stop();
+      }
+    }
+  }
+
+  Future<void> _initRustIsolate() async {
+    _receivePort = ReceivePort();
+
+    _rustIsolate = await Isolate.spawn(
+      _rustIsolateEntryPoint,
+      _receivePort!.sendPort,
+    );
+
+    final completer = Completer<SendPort>();
+    _receivePort!.listen((message) {
+      if (message is SendPort) {
+        completer.complete(message);
+      }
+    });
+
+    _sendPort = await completer.future;
+    _isRunning = true;
+  }
+
+  static Future<void> _rustIsolateEntryPoint(SendPort mainSendPort) async {
+    await RustLib.init();
+
+    final receivePort = ReceivePort();
+    mainSendPort.send(receivePort.sendPort);
+
+    await for (var message in receivePort) {
+      if (message is Map<String, dynamic>) {
+        try {
+          final imageBytes = message['imageBytes'] as Uint8List;
+          final responsePort = message['responsePort'] as SendPort;
+
+          final croppedImage = processCropImage(image: imageBytes);
+
+          responsePort.send({'success': true, 'data': croppedImage});
+        } catch (e) {
+          final responsePort = message['responsePort'] as SendPort;
+          responsePort.send({'success': false, 'error': e.toString()});
+        }
+      } else if (message == 'dispose') {
+        RustLib.dispose();
+        break;
+      }
+    }
+  }
+
+  Future<Uint8List?> process(Uint8List imageBytes) async {
+    await start();
+    if (_sendPort == null) {
+      if (kDebugMode) {
+        print('Image crop isolate is not running');
+      }
+      return null;
+    }
+
+    final responsePort = ReceivePort();
+    final completer = Completer<Uint8List?>();
+
+    responsePort.listen((response) {
+      responsePort.close();
+      if (response is Map<String, dynamic>) {
+        if (response['success'] == true) {
+          completer.complete(response['data'] as Uint8List);
+        } else {
+          if (kDebugMode) {
+            print('Image cropping failed: ${response['error']}');
+          }
+          completer.complete(Future.value(null));
+        }
+      }
+    });
+
+    _sendPort!.send({
+      'imageBytes': imageBytes,
+      'responsePort': responsePort.sendPort,
+    });
+
+    return completer.future;
+  }
+
+  Future<void> stop() async {
+    if (!_isRunning) {
+      return;
+    }
+
+    _sendPort?.send('dispose');
+    _rustIsolate?.kill(priority: Isolate.immediate);
+    _receivePort?.close();
+    _sendPort = null;
+    _rustIsolate = null;
+    _receivePort = null;
+    _isRunning = false;
+  }
+}
+
+final imgCropIsolate = ImageCropIsolate();

lib/modules/manga/reader/reader_view.dart

@@ -1397,6 +1397,7 @@ class _MangaChapterPageGalleryState
   }
 
   void _processCropBorders() async {
+    if (_cropBorderCheckList.length == _uChapDataPreload.length) return;
     for (var i = 0; i < _uChapDataPreload.length; i++) {
       if (!_cropBorderCheckList.contains(i)) {
         _cropBorderCheckList.add(i);