Use async native_imaging

lib/utils/resize_image.dart

@@ -4,102 +4,56 @@ import 'dart:typed_data';
 import 'package:famedlysdk/famedlysdk.dart';
 import 'package:native_imaging/native_imaging.dart' as native;
 
-import 'run_in_background.dart';
-
 Future<MatrixImageFile> resizeImage(MatrixImageFile file,
     {int max = 800}) async {
-  // we want to resize the image in a separate isolate, because otherwise that can
-  // freeze up the UI a bit
-
-  // we can't do width / height fetching in a separate isolate, as that may use the UI stuff
   await native.init();
 
-  _IsolateArgs args;
-  try {
-    final nativeImg = native.Image();
-    await nativeImg.loadEncoded(file.bytes);
-    file.width = nativeImg.width;
-    file.height = nativeImg.height;
-    args = _IsolateArgs(
-        width: file.width, height: file.height, bytes: file.bytes, max: max);
-    nativeImg.free();
-  } on UnsupportedError {
-    final dartCodec = await instantiateImageCodec(file.bytes);
-    final dartFrame = await dartCodec.getNextFrame();
-    file.width = dartFrame.image.width;
-    file.height = dartFrame.image.height;
-    final rgbaData = await dartFrame.image.toByteData();
-    final rgba = Uint8List.view(
-        rgbaData.buffer, rgbaData.offsetInBytes, rgbaData.lengthInBytes);
-    dartFrame.image.dispose();
-    dartCodec.dispose();
-    args = _IsolateArgs(
-        width: file.width, height: file.height, bytes: rgba, max: max);
-  }
-
-  final res = await runInBackground(_isolateFunction, args);
-  file.blurhash = res.blurhash;
-  final thumbnail = MatrixImageFile(
-    bytes: res.jpegBytes,
-    name: file.name != null
-        ? 'scaled_' + file.name.split('.').first + '.jpg'
-        : 'thumbnail.jpg',
-    mimeType: 'image/jpeg',
-    width: res.width,
-    height: res.height,
-  );
-  // only return the thumbnail if the size actually decreased
-  return thumbnail.size >= file.size ? file : thumbnail;
-}
-
-class _IsolateArgs {
-  final int width;
-  final int height;
-  final Uint8List bytes;
-  final int max;
-  final String name;
-  _IsolateArgs({this.width, this.height, this.bytes, this.max, this.name});
-}
-
-class _IsolateResponse {
-  final String blurhash;
-  final Uint8List jpegBytes;
-  final int width;
-  final int height;
-  _IsolateResponse({this.blurhash, this.jpegBytes, this.width, this.height});
-}
-
-Future<_IsolateResponse> _isolateFunction(_IsolateArgs args) async {
-  await native.init();
   var nativeImg = native.Image();
-
   try {
-    await nativeImg.loadEncoded(args.bytes);
+    try {
-  } on UnsupportedError {
+      await nativeImg.loadEncoded(file.bytes);
-    nativeImg.loadRGBA(args.width, args.height, args.bytes);
+      file.width = nativeImg.width;
-  }
+      file.height = nativeImg.height;
-  if (args.width > args.max || args.height > args.max) {
+    } on UnsupportedError {
-    var w = args.max, h = args.max;
+      final dartCodec = await instantiateImageCodec(file.bytes);
-    if (args.width > args.height) {
+      final dartFrame = await dartCodec.getNextFrame();
-      h = args.max * args.height ~/ args.width;
+      file.width = dartFrame.image.width;
-    } else {
+      file.height = dartFrame.image.height;
-      w = args.max * args.width ~/ args.height;
+      final rgbaData = await dartFrame.image.toByteData();
+      final rgba = Uint8List.view(
+          rgbaData.buffer, rgbaData.offsetInBytes, rgbaData.lengthInBytes);
+      dartFrame.image.dispose();
+      dartCodec.dispose();
+      nativeImg.loadRGBA(file.width, file.height, rgba);
     }
 
-    final scaledImg = nativeImg.resample(w, h, native.Transform.lanczos);
+    if (file.width > max || file.height > max) {
+      var w = max, h = max;
+      if (file.width > file.height) {
+        h = max * file.height ~/ file.width;
+      } else {
+        w = max * file.width ~/ file.height;
+      }
+
+      final scaledImg =
+          await nativeImg.resample(w, h, native.Transform.lanczos);
+      nativeImg.free();
+      nativeImg = scaledImg;
+    }
+
+    final jpegBytes = await nativeImg.toJpeg(75);
+    file.blurhash = await nativeImg.toBlurhash(3, 3);
+
+    return (jpegBytes.length > file.size ~/ 2)
+        ? null
+        : MatrixImageFile(
+            bytes: jpegBytes,
+            name: 'thumbnail.jpg',
+            mimeType: 'image/jpeg',
+            width: nativeImg.width,
+            height: nativeImg.height,
+          );
+  } finally {
     nativeImg.free();
-    nativeImg = scaledImg;
   }
-  final jpegBytes = await nativeImg.toJpeg(75);
-  final blurhash = nativeImg.toBlurhash(3, 3);
-
-  final ret = _IsolateResponse(
-      blurhash: blurhash,
-      jpegBytes: jpegBytes,
-      width: nativeImg.width,
-      height: nativeImg.height);
-
-  nativeImg.free();
-
-  return ret;
 }

pubspec.lock

@@ -566,8 +566,8 @@ packages:
     dependency: "direct main"
     description:
       path: "."
-      ref: master
+      ref: isolate
-      resolved-ref: c8eb59c25c4e3a568bd64e4722108ec45259e157
+      resolved-ref: fc24ec9888d32aee082c98cb8451b3cfd6cf4fe1
       url: "https://gitlab.com/famedly/libraries/native_imaging.git"
     source: git
     version: "0.0.1"

pubspec.yaml

@@ -67,7 +67,7 @@ dependencies:
   native_imaging:
     git:
       url: https://gitlab.com/famedly/libraries/native_imaging.git
-      ref: master
+      ref: isolate
   flutter_blurhash: ^0.5.0
   sentry: ">=3.0.0 <4.0.0"
   scroll_to_index: ^1.0.6