Add a zoom (display N candles on N X X (X = 2, 4, 6, 8 .... ) ) chart function to an existing RSI currency strength indicator

i am looking for someone who know how REALLY to make a zoom function of RSI lines currencies

the zoom function consist to display N last candle beginning at 0 line, on the full number of candle of the chart windows ,

by example with parameter zoom ON :

- display the last 10 candle on a windows which display by example 20 candles means it is a "zoom X2"

- display the last 5 candle on a windows which display by example 20 candles means it is a "zoom X4"

- the number of "zoom display" is automatically determined by the indicator depending of the wide candle of the window

Note that nothing else is to be modified

AND as i am on arbitration with a developper who say that he konw how to do that and after 8 days he was not able to do that at all

i will choode only a developper who sho BEFORE be choosen that he know on a standard RSI to do that :

1) ZOOM ON: line begin a 0 at the candle -1 of number candle display of chart  wide of chart 

    (by example the last 5 periods display on chart 15 candles wide and beginning at candle -14