constrainedAxis property
The axis to retain constraints on, if any.
If not set, or set to null (the default), neither axis will retain its constraints. If set to Axis.vertical, then vertical constraints will be retained, and if set to Axis.horizontal, then horizontal constraints will be retained.
Implementation
Axis get constrainedAxis => _constrainedAxis;
Implementation
set constrainedAxis(Axis value) {
if (_constrainedAxis == value)
return;
_constrainedAxis = value;
markNeedsLayout();
}