CurvedAnimation({Animation<double> parent, Curve curve, Curve reverseCurve })

Creates a curved animation.

The parent and curve arguments must not be null.

Source 

CurvedAnimation({
  this.parent,
  this.curve,
  this.reverseCurve
}) {
  assert(parent != null);
  assert(curve != null);
  _updateCurveDirection(parent.status);
  parent.addStatusListener(_updateCurveDirection);
}