Replace the y-values of the LAST sample (x unchanged) — O(log n), for in-flight samples that keep changing, e.g. a forming candle or a ticking last price. Values must be finite.
Stats caveat: min/max only widen under amends. If the amended value was the sole
extreme and retreats, the recorded extreme stays until the next setData. For the
intended use this never happens (a forming candle's high/low only extend), and a
one-amend-wide extreme is the conservative direction for axis fitting.
Append one sample. x must be >= the current last x (non-decreasing). Updates the data,
the per-series min/max pyramids (O(log n) each), and the stats — never an O(n) rebuild.
Full x-domain [first, last]; falls back to [0, 1] when empty.
Combined y-extent across the series flagged visible.
Per-series visibility (index-aligned with the series). Missing or
true entries count as visible.
[min, max], widened to a unit span when degenerate so scales never collapse.
Render-ready view of a dataset, with O(log n)
pushfor streaming/real-time appends.x/y[i]are exact-length (=== n) views over doubling-capacity backing buffers, sox.length === nholds for the binary search while appends stay amortized O(1).xmust be non-decreasing;pushenforces it, the batch constructor trusts the caller (perf).