recede method

@override double recede(double dt)

Similar to advance(), but makes the effect controller move back in time.

If the supplied amount of time dt would push the effect past its starting point, then the effect stops at the start and the "leftover" portion of dt is returned.

Implementation

@override
double recede(double dt) {
  if (_remainingCount == 0 && dt > 0) {
    // When advancing, we do not reset the child on last iteration. Hence,
    // if we recede from the end position the remaining count must be
    // adjusted.
    _remainingCount = 1;
    assert(child.completed);
  }
  var t = child.recede(dt);
  while (t > 0 && _remainingCount < repeatCount) {
    _remainingCount++;
    child.setToEnd();
    t = child.recede(t);
  }
  return t;
}