Function updateZoom

src/core/createRenderCoordinator.ts:2616–2674

()

  };

  const updateZoom = (): void => {
    const cfg = getZoomOptionsConfig(currentOptions);

    if (!cfg) {
      insideZoom?.dispose();
      insideZoom = null;
      unsubscribeZoom?.();
      unsubscribeZoom = null;
      zoomState = null;
      lastOptionsZoomRange = null;
      return;
    }

    if (!zoomState) {
      const constraints = computeEffectiveZoomSpanConstraints();
      zoomState = createZoomState(cfg.start, cfg.end, constraints);
      lastOptionsZoomRange = { start: cfg.start, end: cfg.end };
      unsubscribeZoom = zoomState.onChange((range) => {
        // Coalesce slicing (and visible-bounds recompute) to at most once per rendered frame.
        sliceRenderSeriesDue = true;
        // Immediate render for UI feedback (axes/crosshair/slider).
        requestRender();
        // Debounce resampling; the unified flush will do the work.
        scheduleZoomResample();
        // Ensure listeners get a stable readonly object.
        emitZoomRange({ start: range.start, end: range.end });
      });
    } else {
      const constraints = computeEffectiveZoomSpanConstraints();
      const withConstraints = zoomState as unknown as {
        setSpanConstraints?: (minSpan: number, maxSpan: number) => void;
      };
      withConstraints.setSpanConstraints?.(constraints.minSpan, constraints.maxSpan);

      if (
        lastOptionsZoomRange == null ||
        lastOptionsZoomRange.start !== cfg.start ||
        lastOptionsZoomRange.end !== cfg.end
      ) {
        // Only apply option-provided start/end when:
        // - zoom is first created, or
        // - start/end actually changed in options
        zoomState.setRange(cfg.start, cfg.end);
        lastOptionsZoomRange = { start: cfg.start, end: cfg.end };
      }
    }

    // Only enable inside zoom handler when `{ type: 'inside' }` exists.
    // Requires event manager (HTMLCanvasElement only).
    if (cfg.hasInside && eventManager) {
      if (!insideZoom) {
        insideZoom = createInsideZoom(eventManager, zoomState);
        insideZoom.enable();
      }
    } else {
      insideZoom?.dispose();
      insideZoom = null;
    }