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

我在Chrome、Firefox和MS Edge上使用的唯一一个库是rasterizeHTML。它输出比HTML2Canvas更好的质量，并且仍然受支持，不像HTML2Canvas。

获取元素和下载为PNG

var node= document.getElementById("elementId");
var canvas = document.createElement("canvas");
canvas.height = node.offsetHeight;
canvas.width = node.offsetWidth;
var name = "test.png"

rasterizeHTML.drawHTML(node.outerHTML, canvas)
     .then(function (renderResult) {
            if (navigator.msSaveBlob) {
                window.navigator.msSaveBlob(canvas.msToBlob(), name);
            } else {
                const a = document.createElement("a");
                document.body.appendChild(a);
                a.style = "display: none";
                a.href = canvas.toDataURL();
                a.download = name;
                a.click();
                document.body.removeChild(a);
            }
     });

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

我也在思考这个问题。 我发现这是解决你问题的最好办法

我们可以使用javascript的HTML -to-image库将HTML代码转换为图像

NPM安装html-to-image

HTML代码

<div>
<div id="capture">
 <p>
    <span>Heading Of Image</span><br></br>
    <span>This is color Image</span><br></br>
    <img src="Your/ImagePath/ifany.jpg" width="100%" />
    <span>Footer Of the Image</span>
 </p>
</div>
<h2>Generated Image</h2>
<div id="real">
</div></div>

Javascript代码

var htmlToImage = require('html-to-image');
var node = document.getElementById('capture');
htmlToImage.toJpeg(node, { quality: 1, backgroundColor: "#FFFFFF", height: node.clientHeight, width: node.clientWidth })
    .then(function (dataUrl) {
        var img = new Image();
        img.src = dataUrl;
        var div = document.getElementById("real")
        div.appendChild(img)
    })
    .catch(function (error) {
        console.error('oops, something went wrong!', error);
    });

通过这个例子，你现在可以在<div>标签中看到你的图像，其中id = 'real'。 现在可以在代码中添加保存和下载或上传图像选项。

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.

仅用JavaScript无法100%准确地做到这一点。

有一个Qt Webkit工具，还有一个python版本。如果你想自己做，我已经成功地用可可:

[self startTraverse:pagesArray performBlock:^(int collectionIndex, int pageIndex) {

    NSString *locale = [self selectedLocale];

    NSRect offscreenRect = NSMakeRect(0.0, 0.0, webView.frame.size.width, webView.frame.size.height);
    NSBitmapImageRep* offscreenRep = nil;      

    offscreenRep = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:nil
                                             pixelsWide:offscreenRect.size.width
                                             pixelsHigh:offscreenRect.size.height
                                             bitsPerSample:8
                                             samplesPerPixel:4
                                             hasAlpha:YES
                                             isPlanar:NO
                                             colorSpaceName:NSCalibratedRGBColorSpace
                                             bitmapFormat:0
                                             bytesPerRow:(4 * offscreenRect.size.width)
                                             bitsPerPixel:32];

    [NSGraphicsContext saveGraphicsState];

    NSGraphicsContext *bitmapContext = [NSGraphicsContext graphicsContextWithBitmapImageRep:offscreenRep];
    [NSGraphicsContext setCurrentContext:bitmapContext];
    [webView displayRectIgnoringOpacity:offscreenRect inContext:bitmapContext];
    [NSGraphicsContext restoreGraphicsState];

    // Create a small + large thumbs
    NSImage *smallThumbImage = [[NSImage alloc] initWithSize:thumbSizeSmall];  
    NSImage *largeThumbImage = [[NSImage alloc] initWithSize:thumbSizeLarge];

    [smallThumbImage lockFocus];
    [[NSGraphicsContext currentContext] setImageInterpolation:NSImageInterpolationHigh];  
    [offscreenRep drawInRect:CGRectMake(0, 0, thumbSizeSmall.width, thumbSizeSmall.height)];  
    NSBitmapImageRep *smallThumbOutput = [[NSBitmapImageRep alloc] initWithFocusedViewRect:CGRectMake(0, 0, thumbSizeSmall.width, thumbSizeSmall.height)];  
    [smallThumbImage unlockFocus];  

    [largeThumbImage lockFocus];  
    [[NSGraphicsContext currentContext] setImageInterpolation:NSImageInterpolationHigh];  
    [offscreenRep drawInRect:CGRectMake(0, 0, thumbSizeLarge.width, thumbSizeLarge.height)];  
    NSBitmapImageRep *largeThumbOutput = [[NSBitmapImageRep alloc] initWithFocusedViewRect:CGRectMake(0, 0, thumbSizeLarge.width, thumbSizeLarge.height)];  
    [largeThumbImage unlockFocus];  

    // Write out small
    NSString *writePathSmall = [issueProvider.imageDestinationPath stringByAppendingPathComponent:[NSString stringWithFormat:@"/%@-collection-%03d-page-%03d_small.png", locale, collectionIndex, pageIndex]];
    NSData *dataSmall = [smallThumbOutput representationUsingType:NSPNGFileType properties: nil];
    [dataSmall writeToFile:writePathSmall atomically: NO];

    // Write out lage
    NSString *writePathLarge = [issueProvider.imageDestinationPath stringByAppendingPathComponent:[NSString stringWithFormat:@"/%@-collection-%03d-page-%03d_large.png", locale, collectionIndex, pageIndex]];
    NSData *dataLarge = [largeThumbOutput representationUsingType:NSPNGFileType properties: nil];
    [dataLarge writeToFile:writePathLarge atomically: NO];
}];

希望这能有所帮助!