The room available for the receiver’s accessory view to
- macOS 10.0+
If the ruler is horizontal,
thickness is the height of the accessory view; otherwise, it’s the width. NSRulerViews by default reserve no space for an accessory view.
An NSRulerView automatically increases the reserved thickness as necessary to that of the accessory view. When the accessory view is thinner than the reserved space, it’s centered in that space. If you plan to use several accessory views of different sizes, you should set the reserved thickness beforehand to that of the thickest accessory view, in order to avoid retiling of the NSScrollView.