Function computeCandlestickBodyWidthRange

src/interaction/findCandlestick.ts:59–114

(
  series: ResolvedCandlestickSeriesConfig,
  data: ReadonlyArray<OHLCDataPoint>,
  xScale: LinearScale,
  plotWidthFallback?: number,
)

 * - No DPR conversions are applied here.
 */
export function computeCandlestickBodyWidthRange(
  series: ResolvedCandlestickSeriesConfig,
  data: ReadonlyArray<OHLCDataPoint>,
  xScale: LinearScale,
  plotWidthFallback?: number,
): number {
  if (data.length === 0) return 0;

  const categoryStep = computeCategoryStep(data);

  // Prefer deriving category width from a domain step via xScale.scale(t0 + step) - xScale.scale(t0).
  let categoryWidthRange = 0;
  if (Number.isFinite(categoryStep) && categoryStep > 0) {
    let t0: number | null = null;
    for (let i = 0; i < data.length; i++) {
      const t = getTimestamp(data[i]);
      if (Number.isFinite(t)) {
        t0 = t;
        break;
      }
    }

    if (t0 != null) {
      const p0 = xScale.scale(t0);
      const p1 = xScale.scale(t0 + categoryStep);
      const w = Math.abs(p1 - p0);
      if (Number.isFinite(w) && w > 0) categoryWidthRange = w;
    }
  }

  // Fallback: approximate based on plot width and data length.
  if (!(categoryWidthRange > 0) || !Number.isFinite(categoryWidthRange)) {
    const plotW = Number.isFinite(plotWidthFallback ?? Number.NaN) ? (plotWidthFallback as number) : 0;
    categoryWidthRange = plotW / Math.max(1, data.length);
  }

  // barWidth semantics:
  // - number: width in range units
  // - percent string: percent of category width in range units
  let width = 0;
  const rawBarWidth = series.barWidth;
  if (typeof rawBarWidth === 'number') {
    width = Number.isFinite(rawBarWidth) ? Math.max(0, rawBarWidth) : 0;
  } else if (typeof rawBarWidth === 'string') {
    const p = parsePercent(rawBarWidth);
    width = p == null ? 0 : categoryWidthRange * clamp01(p);
  }

  // Clamp by min/max width (in CSS px; our range-space is CSS px in interaction usage).
  const minW = Number.isFinite(series.barMinWidth) ? Math.max(0, series.barMinWidth) : 0;
  const maxWCandidate = Number.isFinite(series.barMaxWidth) ? Math.max(0, series.barMaxWidth) : Number.POSITIVE_INFINITY;
  const maxW = Math.max(minW, maxWCandidate);
  width = Math.min(Math.max(width, minW), maxW);

  return Number.isFinite(width) ? width : 0;
}

const monotonicTimestampCache = new WeakMap<ReadonlyArray<OHLCDataPoint>, boolean>();