Detrended Price Oscillator

Detrended Price Oscillator link here's what the indicator looks like also here is the script for it

//version=4
study(title="Detrended Price Oscillator", shorttitle="DPO", format=format.price, precision=2, resolution="")
period_ = input(21, title="Length", minval=1)
isCentered = input(false, title="Centered")
barsback = period_/2 + 1
ma = sma(close, period_)
dpo = isCentered ? close[barsback] - ma : close - ma[barsback]
plot(dpo, offset = isCentered ? -barsback : 0, title="Detrended Price Oscillator", color=#43A047)
hline(0, title="Zero Line", color = #787B86)