The scroll view’s horizontal ruler view.
- macOS 10.0+
The value of this property is
nil when the scroll view has no horizontal ruler view.
If the scroll view is set to display a horizontal ruler view and doesn’t yet have one, this property creates an instance of the ruler view class set using the class method setRulerViewClass(_:). You can use this property to override the default ruler class set using the class method setRulerViewClass(_:).
Display of rulers is controlled using the