Filter from File & return File

[loic-hamdi]

Hi,

I am using https://pub.dev/packages/multi_image_picker/ to transform List<Asset> to List<File>
This list is generated as below :

final temp = await Directory.systemTemp.createTemp();
List<File> images = List<File>();
 for (int i = 0; i < assets.length; i++) {
    final data = await assets[i].getByteData();
    images.add(await File('${temp.path}/img$i').writeAsBytes(
      data.buffer.asUint8List(
        data.offsetInBytes, data.lengthInBytes)));
}

From that list, I then display the pictures in a carousel allowing the user to crop the picture and/or apply a filter.

I am struggling to setup the filter example.

I woud like to get the File > apply the filter > replace the previous File with the new one and then setState to update the carousel image.

Where are my mistakes there please ?

  Future<File> applyFilterOnImageFileSaveToFile(Filter filter, File src) async {
    imageLib.Image image = imageLib.decodeImage(src.readAsBytesSync());
    var pixels = image.getBytes();
    filter.apply(pixels, image.width, image.height);
    imageLib.Image out =
        imageLib.Image.fromBytes(image.width, image.height, pixels);
    File destinationFile = new File(src.path)..createSync(recursive: true);
    File(destinationFile.path).writeAsBytesSync(out.getBytes());
    return destinationFile;
  }

GestureDetector(
                       onTap: () async {
                          File newFileWithFilterApplied = await applyFilterOnImageFileSaveToFile(AddictiveRedFilter(), imagesFromMultiPickerReadyForCropping[indexCurrentPhotoCarouselIndex - 1]);
                          setState(() {
                            imagesFromMultiPickerReadyForCropping[indexCurrentPhotoCarouselIndex - 1] = newFileWithFilterApplied;
                          });
                        },
                        },
                      ),