jquery/jquery-ui — pull request #733 by asleepysamurai (2012-10-02 09:53:40+00:00)
Title: Draggable - Snap dragged element to centers

Hi,
I required this functionality recently and thought it might be useful to include in the project. This pull request enables draggable elements to be snapped to the centers of matching snap elements. This is done by adding a new option to draggable - 'snapCenter'.
Usage:
Set 'snapCenter' to either 'none','centers' or 'all'.
none - does not snap to center of snapping element. This is the default behavior of draggable snap.
centers - only snaps if center of the dragged element matches the center of snapping element.
all - snaps if any edge or center of dragging element matches any center or edge of the snapping element.