Rectangle<num> bounds

Source 

@override
Rectangle<num> get bounds {

  double left = double.INFINITY;
  double top = double.INFINITY;
  double right = double.NEGATIVE_INFINITY;
  double bottom = double.NEGATIVE_INFINITY;

  for (int i = 0; i < ixList.length; i++) {
    int index = ixList[i + 0];
    var vertexX = vxList[(index << 2) + 0];
    var vertexY = vxList[(index << 2) + 1];
    if (left > vertexX) left = vertexX;
    if (right < vertexX) right = vertexX;
    if (top > vertexY) top = vertexY;
    if (bottom < vertexY) bottom = vertexY;
  }

  return new Rectangle<num>(left, top, right - left, bottom - top);
}