title: html2canvas ignores my svg elements
body: <p>I try to <strong>print</strong> screen of my page and then save it into <code>base64</code>, it works good but it looks like that <em>svg</em> elements are ignored, and some <em>css</em> styles work bad, like <code>:before</code> and <code>:after</code>, original page looks - <a href="https://i.stack.imgur.com/dyJM0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dyJM0.png" alt="enter image description here"></a></p>
  
  <p>but after conversion it looks like this - <a href="https://i.stack.imgur.com/Rx65t.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Rx65t.png" alt="enter image description here"></a></p>
  
  <p>You can see the <em>circle</em> on right side is ignore, and arrow in top menu and same <code>:before</code> and <code>:after</code> on tabs and add new tab button (+). My convert code looks -</p>
  
  <pre><code>printOnePage(){
          document.getElementById('helpPage').style.display= 'none';
          let page = document.getElementById('appContainer');
          html2canvas(page,{
              onrendered: function(canvas) {
                  $('#img_val').val(canvas.toDataURL("image/png"));
                  console.log(document.getElementById('img_val'));
                  //document.getElementById("phpSendForm").submit();
              }
          });
          document.getElementById('helpPage').style.display= '';
  
      }
  </code></pre>
  
  <p>Any tips what can cause this ?</p>