Returns where on the line to place the text terminal cursor for a currently selected item. By default this
will return 0, meaning the first character of the selected line. If you extend ListItemRenderer you
can change this by returning a different number. Returning -1 will cause lanterna to hide the cursor.
Given a list box, an index of an item within that list box and what the item is, this method should return
what to draw for that item. The default implementation is to return whatever toString() returns when
called on the item.
This is the main drawing method for a single list box item, it applies the current theme to setup the colors
and then calls getLabel(..) and draws the result using the supplied TextGUIGraphics. The
graphics object is created just for this item and is restricted so that it can only draw on the area this
item is occupying. The top-left corner (0x0) should be the starting point when drawing the item.