1. override
double transform(double t)

Returns the value of the curve at point t.

The value of t must be between 0.0 and 1.0, inclusive.

Source 

@override
double transform(double t) {
  double s = period / 4.0;
  return math.pow(2.0, -10 * t) * math.sin((t - s) * (math.PI * 2.0) / period) + 1.0;
}