class PixelSpacing {
  double _physicalDeltaY = 0.0;
  double _physicalDeltaX = 0.0;

  factory PixelSpacing.fill(double physicalDeltaX, double physicalDeltaY) {
    return PixelSpacing()
      .._physicalDeltaX = physicalDeltaX
      .._physicalDeltaY = physicalDeltaY;
  }

  PixelSpacing();

  /// Delta X
  double get physicalDeltaX => _physicalDeltaX;
  set physicalDeltaX(double val) {
    if (val != _physicalDeltaX) {
      _physicalDeltaX = val;
    }
  }

  /// Delta Y
  double get physicalDeltaY => _physicalDeltaY;
  set physicalDeltaY(double val) {
    if (val != _physicalDeltaY) {
      _physicalDeltaY = val;
    }
  }

  /// 是否为空数据
  bool get isEmpty => _physicalDeltaX == 0 || _physicalDeltaY == 0;
}