This indicator is a ported MQL5 indicator from http://www.mql5.com/ru/code/703 (in Russian).
Formulas:
ATR[i]=ATR[i-1]+(TR[i]-TR[i-Period])/Period, where
TR[i]=Max(High[i],Close[i-1])-Min(Low[i],Close[i-1]),
CO[i]=Abs(Close[i-1]-Open[i-1]).
Download:
The indicator was revised and updated