Returns the frame of the collection view item at the specified index.
- macOS 10.6+
The index of the collection view item.
The frame calculated by the receiver where it intends to place the subview for the
NSCollection at the given index. The rectangle is returned in the collection view’s coordinate system.
You can use this method in the
collection method to determine which views are in the visible portion of the enclosing scroll view.
Overriding this method will have no effect on the collection view’s subview layout.