Source Code added

mobile/lib/providers/image/immich_local_image_provider.dart

@@ -0,0 +1,94 @@
+import 'dart:async';
+import 'dart:io';
+import 'dart:ui' as ui;
+
+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/painting.dart';
+import 'package:immich_mobile/entities/asset.entity.dart';
+import 'package:logging/logging.dart';
+import 'package:photo_manager/photo_manager.dart' show ThumbnailSize;
+
+/// The local image provider for an asset
+class ImmichLocalImageProvider extends ImageProvider<ImmichLocalImageProvider> {
+  final Asset asset;
+  // only used for videos
+  final double width;
+  final double height;
+  final Logger log = Logger('ImmichLocalImageProvider');
+
+  ImmichLocalImageProvider({required this.asset, required this.width, required this.height})
+    : assert(asset.local != null, 'Only usable when asset.local is set');
+
+  /// Converts an [ImageProvider]'s settings plus an [ImageConfiguration] to a key
+  /// that describes the precise image to load.
+  @override
+  Future<ImmichLocalImageProvider> obtainKey(ImageConfiguration configuration) {
+    return SynchronousFuture(this);
+  }
+
+  @override
+  ImageStreamCompleter loadImage(ImmichLocalImageProvider key, ImageDecoderCallback decode) {
+    final chunkEvents = StreamController<ImageChunkEvent>();
+    return MultiImageStreamCompleter(
+      codec: _codec(key.asset, decode, chunkEvents),
+      scale: 1.0,
+      chunkEvents: chunkEvents.stream,
+      informationCollector: () sync* {
+        yield ErrorDescription(asset.fileName);
+      },
+    );
+  }
+
+  // Streams in each stage of the image as we ask for it
+  Stream<ui.Codec> _codec(
+    Asset asset,
+    ImageDecoderCallback decode,
+    StreamController<ImageChunkEvent> chunkEvents,
+  ) async* {
+    try {
+      final local = asset.local;
+      if (local == null) {
+        throw StateError('Asset ${asset.fileName} has no local data');
+      }
+
+      switch (asset.type) {
+        case AssetType.image:
+          final File? file = await local.originFile;
+          if (file == null) {
+            throw StateError("Opening file for asset ${asset.fileName} failed");
+          }
+          final buffer = await ui.ImmutableBuffer.fromFilePath(file.path);
+          yield await decode(buffer);
+          break;
+        case AssetType.video:
+          final size = ThumbnailSize(width.ceil(), height.ceil());
+          final thumbBytes = await local.thumbnailDataWithSize(size);
+          if (thumbBytes == null) {
+            throw StateError("Failed to load preview for ${asset.fileName}");
+          }
+          final buffer = await ui.ImmutableBuffer.fromUint8List(thumbBytes);
+          yield await decode(buffer);
+          break;
+        default:
+          throw StateError('Unsupported asset type ${asset.type}');
+      }
+    } catch (error, stack) {
+      log.severe('Error loading local image ${asset.fileName}', error, stack);
+    } finally {
+      unawaited(chunkEvents.close());
+    }
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    if (other is ImmichLocalImageProvider) {
+      return asset.id == other.asset.id && asset.localId == other.asset.localId;
+    }
+    return false;
+  }
+
+  @override
+  int get hashCode => Object.hash(asset.id, asset.localId);
+}