Return the cursor data for a given event.


This method is intended to be overridden by artist subclasses. As an end-user of Matplotlib you will most likely not call this method yourself.

Cursor data can be used by Artists to provide additional context information for a given event. The default implementation just returns None.

Subclasses can override the method and return arbitrary data. However, when doing so, they must ensure that format_cursor_data can convert the data to a string representation.

The only current use case is displaying the z-value of an AxesImage in the status bar of a plot window, while moving the mouse.