{HEAD ~ A detailed calculating method} of the position of {TAIL ~ the touch point C} is familiar to one skilled in the art and is not be described here 
{ HEAD ~ A detailed calculating method } of the position of { TAIL ~ the touch point C } is familiar to one skilled in the art and is not be described here
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH