isFixedToViewport property

Implementation

bool get isFixedToViewport {
  if (renderStyle.position != CSSPositionType.fixed) return false;
  final target = renderStyle.target;
  final viewportElement = target.ownerDocument.documentElement;
  final cb = target.holderAttachedContainingBlockElement;
  // Default to viewport behavior if we haven't attached a containing block yet.
  return cb == null || identical(cb, viewportElement);
}