title: Raw Java 2D implementation of a scrollbar
body: <p>How would I go about writing my own scrollbar using standard Java 2D.</p>
  
  <p>I really don't want to use swing, and I've already made up my own component parts for everything else such as buttons etc.</p>
  
  <p>I'm not really looking for code, rather the math involved in the event changes and the drawing.</p>