Initial commit: imajViewer Flutter Linux image viewer

lib/services/image_manager.dart

@@ -0,0 +1,76 @@
+import 'dart:io';
+import 'package:flutter/material.dart';
+
+class ImageManager extends ChangeNotifier {
+  static final ImageManager _instance = ImageManager._();
+  static ImageManager get instance => _instance;
+  ImageManager._();
+
+  final List<String> _images = [];
+  int _currentIndex = 0;
+
+  List<String> get images => List.unmodifiable(_images);
+  int get currentIndex => _currentIndex;
+  int get imageCount => _images.length;
+
+  String get currentImagePath {
+    if (_images.isEmpty) return '';
+    return _images[_currentIndex];
+  }
+
+  void addImages(List<String> paths) {
+    final validPaths = paths.where((p) {
+      final ext = p.toLowerCase().split('.').last;
+      const supported = ['png', 'jpg', 'jpeg', 'webp', 'bmp', 'gif'];
+      return supported.contains(ext) && File(p).existsSync();
+    }).toList();
+
+    if (validPaths.isEmpty) return;
+
+    _images.addAll(validPaths);
+
+    // Precache images
+    for (final path in validPaths) {
+      precacheImage(FileImage(File(path)), context!);
+    }
+
+    notifyListeners();
+  }
+
+  void setCurrentIndex(int index) {
+    if (index < 0 || index >= _images.length) return;
+    _currentIndex = index;
+    notifyListeners();
+  }
+
+  void nextImage() {
+    if (_images.isEmpty) return;
+    _currentIndex = (_currentIndex + 1) % _images.length;
+    notifyListeners();
+  }
+
+  void previousImage() {
+    if (_images.isEmpty) return;
+    _currentIndex = (_currentIndex - 1 + _images.length) % _images.length;
+    notifyListeners();
+  }
+
+  // Precache needs a BuildContext
+  BuildContext? context;
+
+  /// Configure image cache for high-res images
+  static void configureCache() {
+    PaintingBinding.instance.imageCache.maximumSize = 1000;
+    PaintingBinding.instance.imageCache.maximumSizeBytes = 1024 * 1024 * 1024; // 1 GB
+  }
+
+  set buildContext(BuildContext ctx) {
+    context = ctx;
+  }
+
+  void clear() {
+    _images.clear();
+    _currentIndex = 0;
+    notifyListeners();
+  }
+}