Creates a render object that positions its child.
Source
RenderPositionedBox({ RenderBox child, double widthFactor, double heightFactor, FractionalOffset alignment: FractionalOffset.center }) : _widthFactor = widthFactor, _heightFactor = heightFactor, super(child: child, alignment: alignment) { assert(widthFactor == null || widthFactor >= 0.0); assert(heightFactor == null || heightFactor >= 0.0); }