Code:
#
#Dynamic_Price_Line
#Plots a Horizontal Line that follows the price value selected
input price=close;
input offset=0;
input length = 300;
def sma = SimpleMovingAvg(price, 1, length);
rec line = if IsNaN(sma) then line[1] else sma[offset];
plot priceline=if isnan(sma) then line else double.nan;
priceline.setpaintingStrategy(PaintingStrategy.DASHES);
priceline.setlineWeight(2);
priceline.setdefaultColor(Color.GRAY);
priceline.hideBubble();