normalize method

Image normalize({ List<double> mean = const [0.0, 0.0, 0.0, 0.0], List<double> std = const [1.0, 1.0, 1.0, 1.0], double scale = 1.0, })

will clone data

Implementation

// Image astype(StbiDType dtype) {
//   if (dtype == this.dtype) {
//     return clone();
//   }
// }

Image normalize({
  List<double> mean = const [0.0, 0.0, 0.0, 0.0],
  List<double> std = const [1.0, 1.0, 1.0, 1.0],
  double scale = 1.0,
}) {
  final size = _width * _height * _channels;
  final p = calloc<ffi.Float>(size);
  p
      .asTypedList(size)
      .setAll(
        0,
        values.indexed
            .map((e) => (e.$2.toDouble() / scale - mean[e.$1 % _channels]) / std[e.$1 % _channels])
            .toList(),
      );
  return Image.fromPointer(
    p.cast(),
    width: _width,
    height: _height,
    channels: _channels,
    desiredChannels: _desiredChannels,
    dtype: StbiDType.f32,
  );
}