code: public function writeDrawings(\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $pWorksheet, $includeCharts = false)
      {
          // Create XML writer
          $objWriter = null;
          if ($this->getParentWriter()->getUseDiskCaching()) {
              $objWriter = new XMLWriter(XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
          } else {
              $objWriter = new XMLWriter(XMLWriter::STORAGE_MEMORY);
          }
  
          // XML header
          $objWriter->startDocument('1.0', 'UTF-8', 'yes');
  
          // xdr:wsDr
          $objWriter->startElement('xdr:wsDr');
          $objWriter->writeAttribute('xmlns:xdr', 'http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing');
          $objWriter->writeAttribute('xmlns:a', 'http://schemas.openxmlformats.org/drawingml/2006/main');
  
          // Loop through images and write drawings
          $i = 1;
          $iterator = $pWorksheet->getDrawingCollection()->getIterator();
          while ($iterator->valid()) {
              $this->writeDrawing($objWriter, $iterator->current(), $i);
  
              $iterator->next();
              ++$i;
          }
  
          if ($includeCharts) {
              $chartCount = $pWorksheet->getChartCount();
              // Loop through charts and write the chart position
              if ($chartCount > 0) {
                  for ($c = 0; $c < $chartCount; ++$c) {
                      $this->writeChart($objWriter, $pWorksheet->getChartByIndex($c), $c + $i);
                  }
              }
          }
  
          $objWriter->endElement();
  
          // Return
          return $objWriter->getData();
      }
docs: Write drawings to XML format.
  
  @param \PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $pWorksheet
  @param bool $includeCharts Flag indicating if we should include drawing details for charts
  
  @throws WriterException
  
  @return string XML Output