html2canvas：删除图片上方的空白区域

这让我很着急。 我只是想html2canvas捕获图像 我有这个：

<div id="post" class="xx">Déposer</div>
<canvas width="500" height="200"></canvas>

<script type="text/javascript" src="html2canvas.js"></script>
<script type="text/javascript">
   var canvas = document.querySelector("canvas");
   html2canvas($("#post"), {canvas: canvas}).then(function(canvas) {
        var img = canvas.toDataURL()
        window.open(img); 
   });
</script>

结果是这样的图像:

width and height not corresponding to the size of image

该按钮出现在画布的底部，我想仅保留该按钮，有关如何仅获取该按钮的任何想法吗?

如果更改画布的大小，则结果如下所示：

enter image description here

这是按钮的代码：

<div id="post">
    <div style="float:left;background:url(g.png);width:21px;height:53px;"></div>
   <div id="c" style="float:left;background:url(c.png) repeat-x;height:53px;font-family:arial;text-shadow: -1px -1px rgba(0, 0, 0, 0.3);padding: 12px 20px;font-size: 20px;line-height: 24px;color: rgb(255, 255, 255);text-align: center;vertical-align: middle;text-decoration: none;">Déposer</div>
     <div style="float:left;background:url(d.png);width:21px;height:53px;"></div>
</div>

和文件 : c.pngd.pngg.png

这使得该按钮（页面中没有多余的CSS）: enter image description here

The following code:

<html>
    <head>
        <style>
            canvas {
                border: solid red 1px;
            }
        </style>
    </head>
<div id="post">
    <div style="float:left;background:url(g.png);width:21px;height:53px;"></div>
   <div id="c" style="float:left;background:url(c.png) repeat-x;height:53px;font-family:arial;text-shadow: -1px -1px rgba(0, 0, 0, 0.3);padding: 12px 20px;font-size: 20px;line-height: 24px;color: rgb(255, 255, 255);text-align: center;vertical-align: middle;text-decoration: none;">Déposer</div>
     <div style="float:left;background:url(d.png);width:21px;height:53px;"></div>
</div>
    <canvas width="500" height="200"></canvas>

    <script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript" src="html2canvas.js"></script>
    <script type="text/javascript">
       var canvas = document.querySelector("canvas");
       html2canvas($("#post"), {canvas: canvas});

//.then is an invalid function for html2canvas
/*.then(function(canvas) {
            var img = canvas.toDataURL()
            window.open(img);
       });
*/
    </script>
</html>

Gives me the following results:

enter image description here

From that I would conclude

  • html2canvas has a small amount of padding around where it adds the image to canvas
  • You may have css on your button that may be causing the canvas to push it down farther than you would like