Convert YUV420 to RGB flutter

const shift = (0xFF << 24);
Future<Image> convertYUV420toImageColor(CameraImage image) async {
      try {
        final int width = image.width;
        final int height = image.height;
        final int uvRowStride = image.planes[1].bytesPerRow;
        final int uvPixelStride = image.planes[1].bytesPerPixel;

        print("uvRowStride: " + uvRowStride.toString());
        print("uvPixelStride: " + uvPixelStride.toString());

        // imgLib -> Image package from https://pub.dartlang.org/packages/image
        var img = imglib.Image(width, height); // Create Image buffer

        // Fill image buffer with plane[0] from YUV420_888
        for(int x=0; x < width; x++) {
          for(int y=0; y < height; y++) {
            final int uvIndex = uvPixelStride * (x/2).floor() + uvRowStride*(y/2).floor();
            final int index = y * width + x;

            final yp = image.planes[0].bytes[index];
            final up = image.planes[1].bytes[uvIndex];
            final vp = image.planes[2].bytes[uvIndex];
            // Calculate pixel color
            int r = (yp + vp * 1436 / 1024 - 179).round().clamp(0, 255);
            int g = (yp - up * 46549 / 131072 + 44 -vp * 93604 / 131072 + 91).round().clamp(0, 255);
            int b = (yp + up * 1814 / 1024 - 227).round().clamp(0, 255);     
            // color: 0x FF  FF  FF  FF 
            //           A   B   G   R
            img.data[index] = shift | (b << 16) | (g << 8) | r;
          }
        }

        imglib.PngEncoder pngEncoder = new imglib.PngEncoder(level: 0, filter: 0);
        List<int> png = pngEncoder.encodeImage(img);
        muteYUVProcessing = false;
        return Image.memory(png);  
      } catch (e) {
        print(">>>>>>>>>>>> ERROR:" + e.toString());
      }
      return null;
  }

I have been following this code snippet from How to convert Camera Image to Image in Flutter? to convert YUV to RGB to send the images via WebSockets for ML prediction. Although it works to convert, the resulting image is rotated 90 degrees and the performance is a little bit slow. How I can rotate it?