title: showing the values in google-chart treemap
body: <p>I have created a Treemap using google charts.<br>
  Here is the code:</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
  &lt;script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"&gt;&lt;/script&gt;
  &lt;script type="text/javascript"&gt;
  google.charts.load('current', {'packages':['treemap']});
  google.charts.setOnLoadCallback(drawChart);
  function drawChart() {
    var data = google.visualization.arrayToDataTable([
    ['Location', 'Parent', 'Market trade volume (size)', 'Market increase/decrease (color)'],
    ['Global',    null,                 0,                               0],
    ['America',   'Global',             20,                               0],
    ['Europe',    'Global',             30,                               0],
    ['Asia',      'Global',             10,                               0],
    ['Australia', 'Global',             40,                               0],
    ['Africa',    'Global',             30,                               0],
  ]);
  tree = new 
  google.visualization.TreeMap(document.getElementById('chart_div'));
  google.visualization.events.addListener(tree, 'select', function () {
    tree.setSelection([]);
  });
  tree.draw(data, {
    headerHeight: 15,
    fontColor: 'black',
    showScale: true,
    maxDepth: 2
  });
  }
  &lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;div id="chart_div" style="width: 900px; height: 500px;"&gt;&lt;/div&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>It shows the tree map as:
  <a href="https://i.stack.imgur.com/AUyaV.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AUyaV.jpg" alt="enter image description here"></a></p>
  
  <p>Now, I want to show the values of Market trade volume (size) as well on the treemap (without any action of the mouse). since It has only one layer so directly value can be shown without any calculation.
  I searched in the documentation but couldn't find anything similar.</p>