PivotPoints

Classic floor-trader support and resistance levels, reset each block from the prior block's high, low and close.

PivotPoints computes the classic floor-trader pivot set. The chart is cut into blocks of session_bars bars, counted from the first bar the indicator sees, not by clock time. When a block ends, the indicator averages its high, low and last close into a pivot point, then derives three resistance levels above it and three support levels below. The seven levels stay flat through the next block, then are replaced using the block that just ended.

How to read it

Seven flat price lines drawn on the candles: PP in the middle, R1 to R3 above it, S1 to S3 below.
A line jumps only at a block boundary, every session_bars bars. The jump is a new block, not a move in price.
No lines show over the first block of data, about 2% of the sample's bars at the default setting.
Traders watch for price to stall or turn at a line; a clean break through R1 or S1 is read as a trend.

What it outputs

Pivot point (PP): The middle line: the average of the prior block's high, low and close. Price above it is the usual bias reading for the block.
Resistance 1 (R1): The first line above the pivot: twice the pivot minus the prior block's low.
Support 1 (S1): The first line below the pivot: twice the pivot minus the prior block's high.
Resistance 2 (R2): The second line above: the pivot plus the prior block's high-to-low range.
Support 2 (S2): The second line below: the pivot minus the prior block's high-to-low range.
Resistance 3 (R3): The third line above: the prior block's high plus twice the distance from the pivot to its low.
Support 3 (S3): The third line below: the prior block's low minus twice the distance from the pivot to its high.

Settings

session_bars: Bars per block, counted from the first bar. Raising it makes blocks longer: lines reset less often and sit further apart, since they come from a wider high-low range. Lowering it resets them more often, so they hug recent price; at 1 they redraw every bar.

Pitfalls

Blocks are counted in bars, not clock time. The SPY sample has about 960 bars per trading day, so the default 390 puts the resets at shifting times of day, not at the open.
Lines come only from the block that just ended, so a fast move inside the current block can pass R3 or S3 before any line updates.
A bar with a missing high, low or close is skipped and not counted, which shifts every later block boundary.