transform method

Implementation

@override
Movie transform(double t) {
  final propertyItems = <MovieTweenPropertyType, List<_AbsoluteSceneItem>>{};
  final now = t * duration.inMicroseconds;
  final valueMap = <MovieTweenPropertyType, dynamic>{};

  final allItems = _generateAbsoluteItems();

  /// Presort all items by begin.
  allItems.sort((a, b) => a.begin - b.begin);

  /// Group items by property.
  for (var item in allItems) {
    propertyItems.putIfAbsent(item.property, () => []);
    propertyItems[item.property]!.add(item);
  }

  /// Transform each property for current time [t].
  for (var property in propertyItems.keys) {
    _transformProperty(propertyItems[property]!, property, now, valueMap);
  }

  return Movie(map: valueMap);
}