html2canvas screenshot keeps turning up blank

Question

I am trying to get a screenshot of the images to the right of the mauve line (so below the heading "today's outfit" (screenshot shown below).

I'm using html2canvas to do this, but each time I click the "snapshot" button, I keep getting a blank screenshot.

Here is my HTML:

<div id="sidebar"><br/><center><h1 class = "outfitheading">Today's Outfit</h1></center>
  <div id = "outfit">
    <center><div class = "clothediv" id = "hatdiv" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)">

    </div></center>
    <center><div class = "clothediv" id= "semitopdiv" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)">

      </div></center>


     <center><div class = "clothediv" id = "topdiv" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)">

     </div></center>


   <center><div class = "clothediv" id = "legweardiv" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)">

     </div></center>


  <center><div class = "clothediv" id = "shoediv" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)">
  </div></center>


  </div>

  <button onclick="takeScreenShot()">Snapshot</button>
  <center><div id= "likebutton" style = "display:none; visibility: hidden">
    <a href = "#" ><i id = "outlinehearticon" class="fa fa-heart-o fa-2x" aria-hidden="true" onclick = {fillHeart()}></i></a>
    <a href = "#"  ><i id = "filledhearticon" class="fa fa-heart fa-2x" aria-hidden="true" style = "display:none; visibility: visible" onclick = {unfillHeart()}></i></a>

    <script>
      $(document).ready(function(){
          $('[data-toggle="popover"]').popover(); 
      });
    </script>

  </div></center>
      <br/>
      <br/>
 <div class = "buttons"><center>
      <button class = "btn btn-lg btn-secondary generatebutton" style = "display: inline-block" type = "button"  id= "generateoutfitbutton" onclick = {generateOutfit()}>Generate Outfit</button> 
      <!--<p><center>or</center></p>-->
      &nbsp
      &nbsp

      <button class = "btn btn-lg btn-secondary collagebutton" style = "display: inline-block" type = "button" id= "collagebutton" onclick = {clearCanvas()}>Make your Own</button></center>
</div>

</div>

And here is my javascript:

var takeScreenShot = function() {
    html2canvas(document.getElementById("outfit"), {
        onrendered: function (canvas) {
            var tempcanvas=document.createElement('canvas');
            tempcanvas.width=465.5;
            tempcanvas.height=524;
            var context=tempcanvas.getContext('2d');
            context.drawImage(canvas,465.5,40,465.5,524,0,0,465.5,524);
            var link=document.createElement("a");
            link.href=tempcanvas.toDataURL('image/jpg');   //function blocks CORS
            link.download = 'screenshot.jpg';
            link.click();
        }
    });
}

Here is a shortened-down jsfiddle for my code: https://jsfiddle.net/e51yepcz/

Does anyone know why the snapshot doesn't work or how I can fix it? Thanks.

465.5 ?.. Have you tried using an integer instead? I don't think you will have much luck with half pixels. — 2pha, Aug 05 '17 at 17:39
Have you tried just outputting the canvas that is returned to the onrendered callback instead of your temp canvas? Just to make sure it is what is expected. — 2pha, Aug 05 '17 at 17:46
I tried replacing all the 465.5s with 465s, but I still get blank screenshots. — captain_jon_sparrow, Aug 05 '17 at 17:48
@2pha when I output the canvas instead of tempcanvas, the result is also blank, so I guess that's why I'm getting blank shots with tempcanvas as well; but on console logging the canvas, I can see that the width is 466 and the height is 440 pixels, so do you know why there isn't anything in it? — captain_jon_sparrow, Aug 05 '17 at 18:02
There is no way for me to know without seeing your code, and even then I would just be guessing. I can see you are using `` tags which tells me you are using an old HTML standard or using something old to generate your code. This I think is your main problem. put some interactive code somewhere (in your post or jsfiddle) if you want more help — 2pha, Aug 06 '17 at 02:42

Kurohige · Accepted Answer · 2017-08-06T20:11:12.617

1

I edited your fiddle and got following error:

Uncaught ReferenceError: takeScreenShot is not defined

So I changed something and seems to work.

I added an id to your button:

<center><button id="snap">Snapshot</button></center>

and the javascript event (jQuery):

 $('#snap').click(function () {
 html2canvas(document.getElementById("outfit"), {
 onrendered: function(canvas) {
    var tempcanvas = document.createElement('canvas');
    tempcanvas.width=465;
    tempcanvas.height=524;
    var context=tempcanvas.getContext('2d');
    context.drawImage(canvas,465,40,465,524,0,0,465,524);
    var link=document.createElement("a");
    link.href=canvas.toDataURL('image/jpg');
    link.download = 'screenshot.jpg';
    link.click();
    }
  });
});

Here is the JsFiddle

edited Aug 06 '17 at 20:11

answered Aug 06 '17 at 20:05

Kurohige

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This works, thanks! But if I want to append images to the divs on the click of a different button and then take a snapshot of the div "outfit", the divs inside "outfit" turn out empty even though there are images in them. – captain_jon_sparrow Aug 06 '17 at 20:18
is the image in the same server? https://github.com/niklasvh/html2canvas/issues/722 – Kurohige Aug 06 '17 at 20:54
They aren't, which is why I passed in the option allowTaint and set it equal to true in the jquery, but then the snapshot does not even appear, yet I don't get any errors either. Here's an updated jsfiddle with the "allowTaint"-- maybe my syntax is wrong? https://jsfiddle.net/e51yepcz/3/ – captain_jon_sparrow Aug 06 '17 at 21:25
[this](https://stackoverflow.com/questions/41254805/how-to-generate-screenshot-of-html-div-with-external-images) may help :) – Kurohige Aug 06 '17 at 22:58

html2canvas screenshot keeps turning up blank

1 Answers1