axisDirection property

AxisDirection axisDirection

The direction in which the SliverConstraints.scrollOffset increases.

For example, if the axisDirection is AxisDirection.down, a scroll offset of zero is at the top of the viewport and increases towards the bottom of the viewport.

Implementation 

AxisDirection get axisDirection => _axisDirection;
void axisDirection= (AxisDirection value)

Implementation 

set axisDirection(AxisDirection value) {
  assert(value != null);
  if (value == _axisDirection)
    return;
  _axisDirection = value;
  markNeedsLayout();
}