isNonNegative property

bool isNonNegative

Whether every dimension is non-negative.

Implementation 

bool get isNonNegative {
  return _left >= 0.0
      && _right >= 0.0
      && _start >= 0.0
      && _end >= 0.0
      && _top >= 0.0
      && _bottom >= 0.0;
}