MaterialRectArcTween({@required Rect begin, @required Rect end })

Creates a Tween for animating Rects along a circular arc.

The begin and end points are required, cannot be null, and are immutable.

Source 

MaterialRectArcTween({
  @required Rect begin,
  @required Rect end
}) : super(begin: begin, end: end) {
  assert(begin != null);
  assert(end != null);
  final Offset centersVector = end.center - begin.center;
  _diagonal = _maxBy/*<_Diagonal>*/(_allDiagonals, (_Diagonal d) => _diagonalSupport(centersVector, d));
  _beginArc = new MaterialPointArcTween(
    begin: _cornerFor(begin, _diagonal.beginId),
    end: _cornerFor(end, _diagonal.beginId)
  );
  _endArc = new MaterialPointArcTween(
    begin: _cornerFor(begin, _diagonal.endId),
    end: _cornerFor(end, _diagonal.endId)
  );
}