Defines the options that can be set for the text that is displayed by the scale markers.
Specifies a callback function that returns the text to be displayed in scale markers.
When implementing a callback function for this property, use the value to be displayed in the marker. This value can be accessed using the fields of the object that is passed as the function's parameter. Alternatively, you can use the this object within the function. This object has the same structure as the object passed as a parameter.
Specifies a format for the text displayed in scale markers.