//@version=6
indicator("Workshop 18 Footprint Delta", overlay=false)
ticks = input.int(10, "Ticks per row", minval=1)
fp = request.footprint(ticks)
available = not na(fp)
delta = available ? footprint.delta(fp) : na
plot(delta, "Categorized volume delta",
    color=color.blue, style=plot.style_columns)
hline(0, "Equal classified volumes", color=color.gray)