Creates a render box that sizes its child to a fraction of the total available space.
If non-null, the widthFactor and heightFactor arguments must be
non-negative.
Source
RenderFractionallySizedOverflowBox({
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);
}