[flexcoders] Extending ScrollControlBase to implement scrolling for a custom component

[m.ar80]

What ScrollControlBase methods should be overridden to implement
scrolling for a custom component? For example, if I have a custom
component that has fixed dimensions of 500x500 and a variable viewable
area of let's say 200x200, which properties would need to be set?
Also, is extending ScrollControlBase the best way to implement
scrolling for a
custom component? Thanks.