cant print jspdf on column chart

a good day to all. I was trying to make a pdf file out of my column chart ( google charts), im using jspdf. when i try to make a pdf file out of bar and pie chart seems the code works fine

But when i try to code it on a column chart it wont print pdf

I tried to search on my code but it seems good

google.charts.load('current', {'packages':['bar']});
  google.charts.setOnLoadCallback(drawChart);

  function drawChart() {
    var data = google.visualization.arrayToDataTable([
      ['Year', 'Sales', 'Expenses', 'Profit'],
      ['2014', 1000, 400, 200],
      ['2015', 1170, 460, 250],
      ['2016', 660, 1120, 300],
      ['2017', 1030, 540, 350]
    ]);

    var options = {
      chart: {
        title: 'Company Performance',
        subtitle: 'Sales, Expenses, and Profit: 2014-2017',
      }
    };

    var chart = new 
 google.charts.Bar(document.getElementById('columnchart_material'));
 var btnSave = document.getElementById('save-pdf');
      google.visualization.events.addListener(chart, 'ready', function () {
btnSave.disabled = false;
   });
 btnSave.addEventListener('click', function () {
var doc = new jsPDF();
doc.addImage(chcolumnchart_material.getImageURI(),  10, 10, 180, 150);
doc.save('chart.pdf');
  }, false);
    chart.draw(data, google.charts.Bar.convertOptions(options));
      }

    <script type="text/javascript" 
    src="https://www.gstatic.com/charts/loader.js"></script>
    <script 
   src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.3.5/jspdf.min.js"> 
   </script>
     <input id="save-pdf" type="button" value="Save as PDF" disabled />
    <div id="columnchart_material" style="width: 800px; height: 500px;"></div>

chart method getImageURI() is not supported by material charts.

material --> google.charts.Bar -- packages: ['bar']

you'll need to use a classic chart.

classic --> google.visualization.BarChart -- packages: ['corechart']
or --> google.visualization.ColumnChart

note: there is a config option to style classic charts similar to material charts...

theme: 'material'