Ordinary node with text title

Audio/Video/Image node

Drawing node

Tag enable

Resizeable

Different shape

Non-directional

Using straight line in this phase

Multiple links between the same two nodes is possible

Tag enable

Different shape

Coloring

Text discription

Not yet decide since there is implementation issue, need further study to decide

Text base (xml or custom form)

Using CoreData?

Some of the control may be add/remove if there are changes in the UI design

Drag to move nodes

Pinch to zoom in/out

Create nodes by double click with the help of UI (choosing between different kind of nodes)

Delete nodes by double click with the help of UI

Create linkage by tap once on the original node and hold for a few seconds, then drag a line to the new node