HtmlToImage.jar是将html转换为图像的最简单方法

使用java将HTML转换为图像

你可以添加引用HtmlRenderer到你的项目，并执行以下操作:

string htmlCode ="<p>This is a sample html.</p>";
Image image = HtmlRender.RenderToImage(htmlCode ,new Size(500,300));

这里所有的答案都使用第三方库，而在纯Javascript中将HTML渲染为图像可以相对简单。在MDN的画布部分甚至有一篇关于它的文章。

诀窍是这样的:

使用包含XHTML的foreignObject节点创建SVG 将图像的src设置为该SVG的数据url 将图像绘制到画布上 将画布数据设置为目标image.src

const {body} = document const canvas = document.createElement('canvas') const ctx = canvas.getContext('2d') canvas.width = canvas.height = 100 const tempImg = document.createElement('img') tempImg.addEventListener('load', onTempImageLoad) tempImg.src = 'data:image/svg+xml,' + encodeURIComponent('<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100"><foreignObject width="100%" height="100%"><div xmlns="http://www.w3.org/1999/xhtml"><style>em{color:red;}</style><em>I</em> lick <span>cheese</span></div></foreignObject></svg>') const targetImg = document.createElement('img') body.appendChild(targetImg) function onTempImageLoad(e){ ctx.drawImage(e.target, 0, 0) targetImg.src = canvas.toDataURL() }

需要注意的一些事情

The HTML inside the SVG has to be XHTML For security reasons the SVG as data url of an image acts as an isolated CSS scope for the HTML since no external sources can be loaded. So a Google font for instance has to be inlined using a tool like this one. Even when the HTML inside the SVG exceeds the size of the image it wil draw onto the canvas correctly. But the actual height cannot be measured from that image. A fixed height solution will work just fine but dynamic height will require a bit more work. The best is to render the SVG data into an iframe (for isolated CSS scope) and use the resulting size for the canvas.

请允许我推荐dom-to-image库，这是专门用来解决这个问题的(我是维护者)。 下面是你如何使用它(更多):

var node = document.getElementById('my-node');

domtoimage.toPng(node)
    .then (function (dataUrl) {
        var img = new Image();
        img.src = dataUrl;
        document.appendChild(img);
    })
    .catch(function (error) {
        console.error('oops, something went wrong!', error);
    });

我知道这是一个已经有很多答案的老问题，但我仍然花了很多时间去做我想做的事情:

给定一个HTML文件，从命令行生成一个带有透明背景的(png)图像

使用Chrome headless (version 74.0.3729.157)，实际上很容易:

"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome" --headless --screenshot --window-size=256,256 --default-background-color=0 button.html

命令使用说明:

you run Chrome from the command line (here shown for the Mac, but assuming similar on Windows or Linux) --headless runs Chrome without opening it and exits after the command completes --screenshot will capture a screenshot (note that it generates a file called screenshot.png in the folder where the command is run) --window-size allow to only capture a portion of the screen (format is --window-size=width,height) --default-background-color=0 is the magic trick that tells Chrome to use a transparent background, not the default white color finally you provide the html file (as a url either local or remote...)

使用这段代码，它一定会工作:

<脚本type = " text / javascript”> 美元(文档)。Ready (function () { setTimeout(函数(){ downloadImage (); }, 1000) })； 函数downloadImage () { html2canvas (document.querySelector(“# dvContainer”))。然后(canvas => { a = document.createElement('a'); document.body.appendChild(一个); A.download = "test.png"; a.href = canvas.toDataURL(); a.click (); })； ｝ > < /脚本

不要忘记在你的程序中包含Html2CanvasJS文件。 https://html2canvas.hertzen.com/dist/html2canvas.js