title: How to scroll efficiently in an NSScrollview with huge amount of data?
body: <p>I'm scrolling in a huge set of data points (CGPoints in a custom view, like a graph) and its obviously slow and laggy. Is there a common way to load and draw only the chunk of data I need to display? Does [[[myScrollview] documentView] documentVisibleRect] the trick? 
  I also want to zoom in and out and therefore change the data point's detail. 
  Thanks for any tips. </p>