是否可以捕获或打印html画布中显示的图像或pdf?

我希望通过画布生成图像,并能够从该图像生成png。


当前回答

您可以使用jspdf将画布捕获为图像或pdf,如下所示:

var imgData = canvas.toDataURL('image/png');              
var doc = new jsPDF('p', 'mm');
doc.addImage(imgData, 'PNG', 10, 10);
doc.save('sample-file.pdf');

更多信息:https://github.com/MrRio/jsPDF

其他回答

我会使用“wkhtmltopdf”。它工作得很好。它使用webkit引擎(在Chrome、Safari等中使用),并且非常容易使用:

wkhtmltopdf stackoverflow.com/questions/923885/ this_question.pdf

就是这样!

试试看

function exportCanvasAsPNG(id, fileName) {

    var canvasElement = document.getElementById(id);

    var MIME_TYPE = "image/png";

    var imgURL = canvasElement.toDataURL(MIME_TYPE);

    var dlLink = document.createElement('a');
    dlLink.download = fileName;
    dlLink.href = imgURL;
    dlLink.dataset.downloadurl = [MIME_TYPE, dlLink.download, dlLink.href].join(':');

    document.body.appendChild(dlLink);
    dlLink.click();
    document.body.removeChild(dlLink);
}

如果您正在使用jQuery(很多人都这么做),那么您可以这样实现接受的答案:

var canvas = $("#mycanvas")[0];
var img = canvas.toDataURL("image/png");

$("#elememt-to-write-to").html('<img src="'+img+'"/>');

从<canvas/>上载图像:

async function canvasToBlob(canvas) {
  if (canvas.toBlob) {
    return new Promise(function (resolve) {
      canvas.toBlob(resolve)
    })
  } else {
    throw new Error('canvas.toBlob Invalid')
  }
}

await canvasToBlob(yourCanvasEl)

如果你想让画布消失,你可以使用这个片段

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <canvas id=canvas width=200 height=200></canvas>
    <iframe id='img' width=200 height=200></iframe>
    <script>
        window.onload = function() {
            var canvas = document.getElementById("canvas");
            var context = canvas.getContext("2d");
            context.fillStyle = "green";
            context.fillRect(50, 50, 100, 100);
            document.getElementById('img').src = canvas.toDataURL("image/jpeg");
            console.log(canvas.toDataURL("image/jpeg"));
        }
    </script>
</body>
</html>