code: public static function cellDimensionToPixels($pValue, \PhpOffice\PhpSpreadsheet\Style\Font $pDefaultFont)
      {
          // Font name and size
          $name = $pDefaultFont->getName();
          $size = $pDefaultFont->getSize();
  
          if (isset(Font::$defaultColumnWidths[$name][$size])) {
              // Exact width can be determined
              $colWidth = $pValue * Font::$defaultColumnWidths[$name][$size]['px'] / Font::$defaultColumnWidths[$name][$size]['width'];
          } else {
              // We don't have data for this particular font and size, use approximation by
              // extrapolating from Calibri 11
              $colWidth = $pValue * $size * Font::$defaultColumnWidths['Calibri'][11]['px'] / Font::$defaultColumnWidths['Calibri'][11]['width'] / 11;
          }
  
          // Round pixels to closest integer
          $colWidth = (int) round($colWidth);
  
          return $colWidth;
      }
docs: Convert column width from (intrinsic) Excel units to pixels.
  
  @param float $pValue Value in cell dimension
  @param \PhpOffice\PhpSpreadsheet\Style\Font $pDefaultFont Default font of the workbook
  
  @return int Value in pixels