feat: Pass through a custom image

resize function to the client

This allows the use of the
native imaging package in a more
easy way.

lib/src/client.dart

@@ -104,6 +104,9 @@ class Client extends MatrixApi {
 
   final Duration sendTimelineEventTimeout;
 
+  MatrixImageFileResizedResponse? Function(MatrixImageFileResizeArguments)?
+      customImageResizer;
+
   /// Create a client
   /// [clientName] = unique identifier of this client
   /// [databaseBuilder]: A function that creates the database instance, that will be used.
@@ -141,6 +144,8 @@ class Client extends MatrixApi {
   /// code in background.
   /// Set [timelineEventTimeout] to the preferred time the Client should retry
   /// sending events on connection problems or to `Duration.zero` to disable it.
+  /// Set [customImageResizer] to your own implementation for a more advanced
+  /// and faster image resizing experience.
   Client(
     this.clientName, {
     this.databaseBuilder,
@@ -164,6 +169,7 @@ class Client extends MatrixApi {
     Level? logLevel,
     Filter? syncFilter,
     this.sendTimelineEventTimeout = const Duration(minutes: 1),
+    this.customImageResizer,
     @deprecated bool? debug,
   })  : syncFilter = syncFilter ??
             Filter(

lib/src/room.dart

@@ -743,13 +743,16 @@ class Room {
               .unsigned![fileSendingStatusKey] =
           FileSendingStatus.generatingThumbnail.name;
       await _handleFakeSync(syncUpdate);
-      thumbnail ??=
+      thumbnail ??= await file.generateThumbnail(
-          await file.generateThumbnail(compute: client.runInBackground);
+        compute: client.runInBackground,
+        customImageResizer: client.customImageResizer,
+      );
       if (shrinkImageMaxDimension != null) {
         file = await MatrixImageFile.shrink(
           bytes: file.bytes,
           name: file.name,
           maxDimension: shrinkImageMaxDimension,
+          customImageResizer: client.customImageResizer,
         );
       }
     }

lib/src/utils/matrix_file.dart

@@ -105,14 +105,17 @@ class MatrixImageFile extends MatrixFile {
       required String name,
       int maxDimension = 1600,
       String? mimeType,
+      MatrixImageFileResizedResponse? Function(MatrixImageFileResizeArguments)?
+          customImageResizer,
       Future<T> Function<T, U>(FutureOr<T> Function(U arg) function, U arg)?
           compute}) async {
-    final arguments = _ResizeArguments(
+    final arguments = MatrixImageFileResizeArguments(
       bytes: bytes,
       maxDimension: maxDimension,
       fileName: name,
       calcBlurhash: true,
     );
+    customImageResizer ??= _resize;
     final resizedData = compute != null
         ? await compute(_resize, arguments)
         : _resize(arguments);
@@ -154,6 +157,8 @@ class MatrixImageFile extends MatrixFile {
   /// computes a thumbnail for the image
   Future<MatrixImageFile?> generateThumbnail(
       {int dimension = Client.defaultThumbnailSize,
+      MatrixImageFileResizedResponse? Function(MatrixImageFileResizeArguments)?
+          customImageResizer,
       Future<T> Function<T, U>(FutureOr<T> Function(U arg) function, U arg)?
           compute}) async {
     final thumbnailFile = await shrink(
@@ -162,6 +167,7 @@ class MatrixImageFile extends MatrixFile {
       mimeType: mimeType,
       compute: compute,
       maxDimension: dimension,
+      customImageResizer: customImageResizer,
     );
     // the thumbnail should rather return null than the unshrinked image
     if ((thumbnailFile.width ?? 0) > dimension ||
@@ -171,11 +177,11 @@ class MatrixImageFile extends MatrixFile {
     return thumbnailFile;
   }
 
-  static _ResizedResponse? _calcMetadata(Uint8List bytes) {
+  static MatrixImageFileResizedResponse? _calcMetadata(Uint8List bytes) {
     final image = decodeImage(bytes);
     if (image == null) return null;
 
-    return _ResizedResponse(
+    return MatrixImageFileResizedResponse(
       bytes: bytes,
       width: image.width,
       height: image.height,
@@ -187,7 +193,8 @@ class MatrixImageFile extends MatrixFile {
     );
   }
 
-  static _ResizedResponse? _resize(_ResizeArguments arguments) {
+  static MatrixImageFileResizedResponse? _resize(
+      MatrixImageFileResizeArguments arguments) {
     final image = decodeImage(arguments.bytes);
 
     final resized = copyResize(image!,
@@ -197,7 +204,7 @@ class MatrixImageFile extends MatrixFile {
     final encoded = encodeNamedImage(resized, arguments.fileName);
     if (encoded == null) return null;
     final bytes = Uint8List.fromList(encoded);
-    return _ResizedResponse(
+    return MatrixImageFileResizedResponse(
       bytes: bytes,
       width: resized.width,
       height: resized.height,
@@ -212,13 +219,13 @@ class MatrixImageFile extends MatrixFile {
   }
 }
 
-class _ResizedResponse {
+class MatrixImageFileResizedResponse {
   final Uint8List bytes;
   final int width;
   final int height;
   final String? blurhash;
 
-  const _ResizedResponse({
+  const MatrixImageFileResizedResponse({
     required this.bytes,
     required this.width,
     required this.height,
@@ -226,13 +233,13 @@ class _ResizedResponse {
   });
 }
 
-class _ResizeArguments {
+class MatrixImageFileResizeArguments {
   final Uint8List bytes;
   final int maxDimension;
   final String fileName;
   final bool calcBlurhash;
 
-  const _ResizeArguments({
+  const MatrixImageFileResizeArguments({
     required this.bytes,
     required this.maxDimension,
     required this.fileName,