Scrolling, Swiping, Dragging: Now with more animation!

Scrolling and drag and drop have undergone major improvements in Lion. Get introduced to the new scrolling behavior and learn why up is now down, and down is now up. Discover the new scroll wheel event properties providing a wealth of new information about each scroll event. Learn how to customize scrolling in NSScrollView such as setting a custom background for rubber-banding and setting which axis are allowed to rubber-band. Learn how to track scrolling to perform a fluid swipe animation of your content while playing nice with rubber-banding. No longer be a passive observer of drag and drop. Learn how and when to actively participate by changing the drag images in flight.

WWDC 2011 - macOS