是否有一种方法将html渲染成PNG那样的图像?我知道这是可能的与画布,但我想渲染标准的html元素,如div为例。
当前回答
你可以使用像wkhtmltopdf这样的HTML转PDF工具。然后你可以使用像imagemagick这样的PDF图像工具。不可否认,这是服务器端,一个非常复杂的过程…
其他回答
安装幻影
$ npm install phantomjs
用以下代码创建一个文件github.js
var page = require('webpage').create();
//viewportSize being the actual size of the headless browser
page.viewportSize = { width: 1024, height: 768 };
page.open('http://github.com/', function() {
page.render('github.png');
phantom.exit();
});
将文件作为参数传递给phantomjs
$ phantomjs github.js
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!
是的,你可以用HTML2Canvas库它渲染你的HTML代码到画布。 它提供了将html从特定div转换为图像的选项,然后使用canvas2image将图像本地下载到您的文件系统中。
链接源代码
html2canvas(document.querySelector('#screenscoot'), {
onrendered: function(canvas) {
// document.body.appendChild(canvas);
return Canvas2Image.saveAsPNG(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);
}
});
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