dragTypeAt method
The drag a press at localPos (planner-local coordinates) would begin, or
DragType.none when it lands on no draggable event. Drives the desktop
hover cursor (move over an event body, resize over its top/bottom edge) and
shares Event.dragTypeForGridPoint with startDrag, so the cursor matches
the drag a press there would start. Spanning events are read-only (#47), so
they report DragType.none (no move/resize affordance).
Implementation
DragType dragTypeAt(Offset localPos) {
final event = getEventAtPos(localPos);
if (event == null || event.entry.time.spansColumns) return DragType.none;
return event.dragTypeForGridPoint(_toGridPos(localPos));
}