Function createRenderCoordinator

src/core/createRenderCoordinator.ts:1469–5044

(
  gpuContext: GPUContextLike,
  options: ResolvedChartGPUOptions,
  callbacks?: RenderCoordinatorCallbacks
)

};

export function createRenderCoordinator(
  gpuContext: GPUContextLike,
  options: ResolvedChartGPUOptions,
  callbacks?: RenderCoordinatorCallbacks
): RenderCoordinator {
  if (!gpuContext.initialized) {
    throw new Error('RenderCoordinator: gpuContext must be initialized.');
  }
  const device = gpuContext.device;
  if (!device) {
    throw new Error('RenderCoordinator: gpuContext.device is required.');
  }
  if (!gpuContext.canvas) {
    throw new Error('RenderCoordinator: gpuContext.canvas is required.');
  }
  if (!gpuContext.canvasContext) {
    throw new Error('RenderCoordinator: gpuContext.canvasContext is required.');
  }

  // Listen for device loss and emit callback
  // Note: We don't call dispose() here to avoid double-cleanup if user calls dispose() in callback.
  // The coordinator is effectively non-functional after device loss until re-created.
  device.lost.then((info) => {
    callbacks?.onDeviceLost?.(info.message || info.reason || 'unknown');
  }).catch(() => {
    // Ignore errors in device.lost promise (can occur if device is destroyed before lost promise resolves)
  });

  const targetFormat = gpuContext.preferredFormat ?? DEFAULT_TARGET_FORMAT;
  
  // DOM-dependent features (overlays, legends) require HTMLCanvasElement and domOverlays !== false.
  // OffscreenCanvas is for rendering only.
  const domOverlaysEnabled = callbacks?.domOverlays !== false;
  const overlayContainer = domOverlaysEnabled && isHTMLCanvasElement(gpuContext.canvas) ? gpuContext.canvas.parentElement : null;
  const axisLabelOverlay: TextOverlay | null = overlayContainer ? createTextOverlay(overlayContainer) : null;
  // Dedicated overlay for annotations (do not reuse axis label overlay).
  const annotationOverlay: TextOverlay | null = overlayContainer ? createTextOverlay(overlayContainer) : null;
  const legend: Legend | null = overlayContainer ? createLegend(overlayContainer, 'right') : null;
  // Text measurement for axis labels. Only available in DOM contexts (not worker threads).
  const tickMeasureCtx: CanvasRenderingContext2D | null = (() => {
    if (typeof document === 'undefined') {
      // Worker thread: DOM not available.
      return null;
    }
    try {
      const c = document.createElement('canvas');
      return c.getContext('2d');
    } catch {
      return null;
    }
  })();
  const tickMeasureCache: Map<string, number> | null = tickMeasureCtx ? new Map() : null;

  let disposed = false;
  let currentOptions: ResolvedChartGPUOptions = options;
  let lastSeriesCount = options.series.length;

  // Story 5.16: initial-load intro animation (series marks only).