Function computeBarHitTestLayout

src/interaction/findPointsAtX.ts:57–93

(
  series: ReadonlyArray<ResolvedSeriesConfig>,
  xScale: LinearScale
)

}>;

const computeBarHitTestLayout = (
  series: ReadonlyArray<ResolvedSeriesConfig>,
  xScale: LinearScale
): BarHitTestLayout | null => {
  // Mirror the bar renderer's shared layout math via `computeBarLayoutPx(...)`, but in xScale range units.
  // IMPORTANT: Bar layout depends on all bar series (stacking + grouped slots), not per-series.
  const barSeries: { readonly globalSeriesIndex: number; readonly s: ResolvedBarSeriesConfig }[] = [];
  for (let i = 0; i < series.length; i++) {
    const s = series[i];
    if (s?.type === 'bar') barSeries.push({ globalSeriesIndex: i, s });
  }
  if (barSeries.length === 0) return null;

  const layout = computeBarLayoutPx(
    barSeries.map((b) => b.s),
    xScale
  );

  const barWidthRange = layout.barWidthPx;
  const gap = layout.gapPx;
  const clusterWidth = layout.clusterWidthPx;
  if (!Number.isFinite(barWidthRange) || !(barWidthRange > 0)) return null;

  const clusterIndexByGlobalSeriesIndex = new Map<number, number>();
  for (let i = 0; i < barSeries.length; i++) {
    const globalSeriesIndex = barSeries[i].globalSeriesIndex;
    const clusterIndex = layout.clusterSlots.clusterIndexBySeries[i] ?? 0;
    clusterIndexByGlobalSeriesIndex.set(globalSeriesIndex, clusterIndex);
  }

  return {
    barWidth: barWidthRange,
    gap,
    clusterWidth,
    clusterIndexByGlobalSeriesIndex,
  };
};

const lowerBoundTuple = (data: ReadonlyArray<TuplePoint>, xTarget: number): number => {
  let lo = 0;