title: Multi line header using phpspreadsheet
body: <p>I insert multi line header using phpspreadsheet. Then, I save as xlsx file. I use convertapi to convert the xlsx file to pdf. In pdf, only header line one only aligned to center.</p>
  
  <pre><code>$spreadsheet-&gt;getActiveSheet()-&gt;getHeaderFooter()-&gt;
  setOddHeader('&amp;C&amp;BFirstLine
               SecondLine
               ThirdLine');
  </code></pre>
  
  <p>How to make three lines also aligned to center?
  Thanks in advance.</p>