RenderStack constructor

RenderStack({List<RenderBox> children, AlignmentGeometry alignment: AlignmentDirectional.topStart, TextDirection textDirection, StackFit fit: StackFit.loose, Overflow overflow: Overflow.clip })

Creates a stack render object.

By default, the non-positioned children of the stack are aligned by their top left corners.

Implementation 

RenderStack({
  List<RenderBox> children,
  AlignmentGeometry alignment = AlignmentDirectional.topStart,
  TextDirection textDirection,
  StackFit fit = StackFit.loose,
  Overflow overflow = Overflow.clip,
}) : assert(alignment != null),
     assert(fit != null),
     assert(overflow != null),
     _alignment = alignment,
     _textDirection = textDirection,
     _fit = fit,
     _overflow = overflow {
  addAll(children);
}