Elastic scroll for multi-focus interactions

This paper proposes a novel and efficient multi-focus scroll interface that consists of a two-step operation using a con-tents distortion technique. The displayed content can be handled just like an elastic material that can be shrunk and stretched by a user's fingers. In the first operation, the us-er's dragging temporarily shows the results of the viewport transition of the scroll by elastically distorting the content. This operation allows the user to see both the newly obtained and the original focus on the viewport. Then, three types of simple gestures can be used to perform the second operation such as scrolling, restoring and zooming out to get the demanded focus (or foci).