RelativeRect rect

Get or set the current values in terms of a RelativeRect object.

Source 

RelativeRect get rect => new RelativeRect.fromLTRB(left, top, right, bottom);
void rect=(RelativeRect value)

Source 

set rect(RelativeRect value) {
  top = value.top;
  right = value.right;
  bottom = value.bottom;
  left = value.left;
}