html2canvas 屏幕截图一直显示为空白

Question

我正在尝试获取紫红色线右侧的图像屏幕截图（因此在标题“今天的装备”下方（屏幕截图如下所示）。

我正在使用 html2canvas 来执行此操作，但是每次单击“快照”按钮时，我都会得到一个空白的屏幕截图。

这是我的 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>

这是我的 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();
        }
    });
}

这是我的代码的一个缩短的 jsfiddle： https://jsfiddle.net/e51yepcz/

有谁知道为什么快照不起作用或者我该如何修复它？谢谢。

Answer 1

我编辑了你的小提琴并得到了以下错误：

未捕获的 ReferenceError：未定义 takeScreenShot

所以我改变了一些东西，似乎可以工作。

我为你的按钮添加了一个 id：

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

和javascript事件（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();
    }
  });
});

这里是JsFiddle