ReadonlybeginReadonlyendReadonlygroupsReadonlylengthOptional ReadonlymarksOptional stable per-bin identity — marks[b] names bin b (a category's
column name on the categorical axis). When present, the draw / hit-test /
selection key on this name instead of the bin's begin slot index, so a
pinned selection survives a column reorder (the slot index is not stable).
undefined for a time / value series whose begin is already stable.
Readonlyvalues
A chart-ready view of a stacked / histogram bar series — the multi-segment generalization of BarSeries. Each of the
lengthbins spans[begin[i], end[i]]on the bin axis (time ms, a value, or a band edge) and carries one value pergroup(a stack segment).groupslists the segment identities bottom → top;valuesis a flatlength × groups.lengthgrid in row-major order, so binb's segmentgisvalues[b * groups.length + g].A single-series bar (the BarSeries case) is just
groups.length === 1. Missing / non-finite segment values areNaN— the gap signal a stack skips (no segment, and it contributes nothing to the running total), the sameNumber.isFinitecontract as BarSeries. Segment values are assumed non-negative (counts / durations); a negative value is treated as a gap (diverging stacks are out of scope — see the histogram guide).The bin axis is x for a vertical histogram (bars grow up) and y for a horizontal one (bars grow right); the same grid drives both — the draw layer transposes by orientation, the data does not change.