attachMaskBuffers function

void attachMaskBuffers(Map<String, dynamic> result, List<ByteBuffer> buffers)

Replaces each mask the browser worker named as [width, height, bytes per value, index] in result with [width, height, values] read from buffers: float32 confidences or uint8 categories.

Implementation

void attachMaskBuffers(Map<String, dynamic> result, List<ByteBuffer> buffers) {
  List<Object> mask(List named) {
    final [width as int, height as int, depth as int, index as int] = named;
    final bytes = buffers[index];
    if (bytes.lengthInBytes != width * height * depth) {
      throw StateError('Mask $index has ${bytes.lengthInBytes} bytes.');
    }
    return [
      width,
      height,
      depth == 1 ? bytes.asUint8List() : bytes.asFloat32List(),
    ];
  }

  for (final key in const [
    'confidenceMasks',
    'segmentationMasks',
    'poseSegmentationMasks',
  ]) {
    if (result[key] case final List masks) {
      result[key] = [for (final named in masks) mask(named as List)];
    }
  }
  if (result['categoryMask'] case final List named) {
    result['categoryMask'] = mask(named);
  }
}