html2canvas 无法针对特定数据 uri 正确呈现

Question

我有div这样的

渲染后输出如下所示。

html2canvas 代码：

html2canvas(document.getElementById('widgetElemet'), {
    logging: true,
    profile: true,
    useCORS: true,
    allowTaint: true,
    onrendered: function(canvas) {
        var dataURL = canvas.toDataURL();

        var param = {
            to: emailToArray.validEmails,
            cc: emailCCArray.validEmails,
            bcc: emailBccArray.validEmails,
            emailid: UserDetails.email,
            subject: emailSubject,
            message: emailMessage,
            ImageDataURI: dataURL
        }

        this.postScreenShot(param)    
    }.bind(this)

})

该图像的数据 uri

data:image/svg+xml;base64,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

Answer 1

我刚刚检查了您的 base64 SVG，发现它显示 width 和 height 0，所以这可能是问题所在。

替代解决方案是将与 background-image 相同的 base64 SVG 应用到 div，您的问题将得到解决。

window.takeScreenShot = function() {
  html2canvas(document.getElementById("target"), {
    onrendered: function(canvas) {
      document.body.appendChild(canvas);
    },
    width: 300,
    height: 300
  });
}

#target {
  background-image: url('data:image/svg+xml;base64,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');
  width: 300px;
  height: 300px;
}

button {
  display: block;
  height: 20px;
  margin-top: 10px;
  margin-bottom: 10px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/html2canvas/0.4.1/html2canvas.min.js"></script>

<div id="target">
</div>

<button onclick="takeScreenShot()">to image</button>

Answer 2

我使用的是 .png，但是 html2canvas 无法显示 .png 文件。

所以我使用 svg 而不是 .png -- 将 .png 转换为 .svg。

对我有用。

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