content: import 'dart:ui';
  
  import 'package:flutter/foundation.dart';
  import 'package:flutter/painting.dart';
  
  import 'package:matrix/matrix.dart';
  import 'package:native_imaging/native_imaging.dart' as native;
  
  (int, int) _scaleToBox(int width, int height, {required int boxSize}) {
    final fit = applyBoxFit(
      BoxFit.scaleDown,
      Size(width.toDouble(), height.toDouble()),
      Size(boxSize.toDouble(), boxSize.toDouble()),
    ).destination;
    return (fit.width.round(), fit.height.round());
  }
  
  Future<MatrixImageFileResizedResponse?> customImageResizer(
    MatrixImageFileResizeArguments arguments,
  ) async {
    if (kIsWeb) {
      throw UnsupportedError(
        'customImageResizer only supports non-web platforms.',
      );
    }
  
    await native.init();
  
    var imageBytes = arguments.bytes;
    String? blurhash;
  
    var originalWidth = 0;
    var originalHeight = 0;
    var width = 0;
    var height = 0;
  
    try {
      // for the other platforms
      final dartCodec = await instantiateImageCodec(arguments.bytes);
      final frameCount = dartCodec.frameCount;
      final dartFrame = await dartCodec.getNextFrame();
      final rgbaData = await dartFrame.image.toByteData();
      if (rgbaData == null) {
        return null;
      }
      final rgba = Uint8List.view(
        rgbaData.buffer,
        rgbaData.offsetInBytes,
        rgbaData.lengthInBytes,
      );
  
      width = originalWidth = dartFrame.image.width;
      height = originalHeight = dartFrame.image.height;
  
      var nativeImg = native.Image.fromRGBA(width, height, rgba);
  
      dartFrame.image.dispose();
      dartCodec.dispose();
  
      if (arguments.calcBlurhash) {
        // scale down image for blurhashing to speed it up
        final (blurW, blurH) = _scaleToBox(width, height, boxSize: 100);
        final blurhashImg = nativeImg.resample(
          blurW, blurH,
          // nearest is unsupported...
          native.Transform.bilinear,
        );
  
        blurhash = blurhashImg.toBlurhash(3, 3);
  
        blurhashImg.free();
      }
  
      if (frameCount > 1) {
        // Don't scale down animated images, since those would lose frames.
        nativeImg.free();
      } else {
        final max = arguments.maxDimension;
        if (width > max || height > max) {
          (width, height) = _scaleToBox(width, height, boxSize: max);
  
          final scaledImg =
              nativeImg.resample(width, height, native.Transform.lanczos);
          nativeImg.free();
          nativeImg = scaledImg;
        }
  
        imageBytes = await nativeImg.toJpeg(75);
        nativeImg.free();
      }
    } catch (e, s) {
      Logs().e("Could not generate preview", e, s);
    }
  
    return MatrixImageFileResizedResponse(
      bytes: imageBytes,
      width: width,
      height: height,
      originalWidth: originalWidth,
      originalHeight: originalHeight,
      blurhash: blurhash,
    );
  }
  