Function render

src/core/createRenderCoordinator.ts:3257–4691

()

  };

  const render: RenderCoordinator['render'] = () => {
    assertNotDisposed();
    if (!gpuContext.canvasContext || !gpuContext.canvas) return;

    // Safety: if a render is triggered for other reasons (e.g. pointer movement) while appends
    // are queued, flush them now so this frame draws up-to-date data. This avoids doing any work
    // when there are no appends.
    if (pendingAppendByIndex.size > 0 || zoomResampleDue) {
      cancelScheduledFlush();
      executeFlush({ requestRenderAfter: false });
    }

    if (sliceRenderSeriesDue) {
      sliceRenderSeriesDue = false;
      sliceRenderSeriesToVisibleRange();
    }

    const hasCartesianSeries = currentOptions.series.some((s) => s.type !== 'pie');
    const seriesForIntro = renderSeries;

    // Story 5.16: start/update intro animation once we have drawable series marks.
    if (introPhase !== 'done') {
      const introCfg = resolveIntroAnimationConfig(currentOptions.animation);

      const hasDrawableSeriesMarks = (() => {
        for (let i = 0; i < seriesForIntro.length; i++) {
          const s = seriesForIntro[i]!;
          switch (s.type) {
            case 'pie': {
              // Pie renderer only emits slices with value > 0.
              if (s.data.some((it) => typeof it?.value === 'number' && Number.isFinite(it.value) && it.value > 0)) {
                return true;
              }
              break;
            }
            case 'line':
            case 'area':
            case 'bar':
            case 'scatter':
            case 'candlestick': {
              if (s.data.length > 0) return true;
              break;
            }
            default:
              assertUnreachable(s);
          }
        }
        return false;
      })();

      if (introPhase === 'pending' && introCfg && hasDrawableSeriesMarks) {
        const totalMs = introCfg.delayMs + introCfg.durationMs;
        const easingWithDelay: EasingFunction = (t01) => {
          const t = clamp01(t01);
          if (!(totalMs > 0)) return 1;

          const elapsedMs = t * totalMs;
          if (elapsedMs <= introCfg.delayMs) return 0;