Function getImageDataUrlForCell

frontend/src/utils/download.ts:73–108

(
  cellId: CellId,
)

 * @returns The PNG as a data URL, or undefined if the cell element wasn't found
 */
export async function getImageDataUrlForCell(
  cellId: CellId,
): Promise<string | undefined> {
  const element = findElementForCell(cellId);
  if (!element) {
    return;
  }

  // TODO: This doesn't handle external iframes + normal elements together (eg. in vstack).
  // It will return the iframe only
  const externalIframeDataUrl = await captureExternalIframes(element);
  if (externalIframeDataUrl) {
    return externalIframeDataUrl;
  }

  const startTime = Date.now();
  const dataUrl = await toPng(element, {
    extraStyleContent: HIDE_SCROLLBAR_STYLES,
    // Add these styles so the element output is not clipped
    // Width can be clipped since pdf has limited width
    style: {
      maxHeight: "none",
      overflow: "visible",
    },
    height: element.scrollHeight,
  });
  const timeTaken = Date.now() - startTime;
  if (timeTaken > THRESHOLD_TIME_MS) {
    Logger.debug(
      "toPng operation for element",
      element,
      `took ${timeTaken} ms (exceeds threshold)`,
    );
  }
  return dataUrl;
}

/**
 * Download a cell output as a PNG image file.