Trying to draw HTML and SVG to canvas to save thumbnails of various pieces of a dataviz app.
Currently failing because dataObjectUrl seems to taint HTML5 canvas.
Last active
March 17, 2016 02:13
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Drawing HTML and SVG to Canvas
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| <html xmlns="http://www.w3.org/1999/xhtml"> | |
| <head> | |
| <title>Canvas Drawing</title> | |
| <meta charset="utf-8" /> | |
| </head> | |
| <style> | |
| body, html { | |
| margin: 0; | |
| padding: 0; | |
| } | |
| .left { | |
| position: fixed; | |
| left:0; | |
| top:0; | |
| bottom:0; | |
| right:50%; | |
| background:rgb(188,188,188); | |
| } | |
| .right { | |
| position: fixed; | |
| right:0; | |
| top:0; | |
| bottom:0; | |
| left:50%; | |
| background:rgb(222,222,222); | |
| } | |
| </style> | |
| <script> | |
| function makeViz() { | |
| _testDiv = d3.select(".left") | |
| .append("div") | |
| .attr("class", "target") | |
| .style("font-size", "12px") | |
| .style("background", "white") | |
| .style("border", "1px solid black") | |
| _testDiv.append("div") | |
| .selectAll("p").data([0,0,0]).enter() | |
| .append("p") | |
| .style("border", function (d,i) {return i + "px dashed darkgray"}) | |
| .html("Some kind of sample paragraphs with ") | |
| .append("span") | |
| .style("font-weight", function (d,i) {return i * 450}) | |
| .html("spans.") | |
| _testDiv.append("svg") | |
| .attr("height", 200).attr("width", 300) | |
| .selectAll("circle").data(d3.range(100)) | |
| .enter() | |
| .append("circle") | |
| .style("fill", "blue") | |
| .attr("r", 2) | |
| .attr("cx", function() {return Math.random() * 200}) | |
| .attr("cy", function() {return Math.random() * 300}) | |
| var height = 0; | |
| var width = 0; | |
| d3.select(".right").append("canvas").attr("height", 200).attr("width", 200) | |
| _fakeHTML = d3.select(".right").append("svg") | |
| .attr("class", "rasterize") | |
| .attr("height", 300).attr("width", 300) | |
| .append("foreignObject") | |
| .attr("id", "rasterizeFO") | |
| .attr("height", "200px").attr("width", "200px") | |
| var itm = d3.select("div.target").node(); | |
| var cln = itm.cloneNode(true); | |
| d3.select("#rasterizeFO").node().appendChild(cln); | |
| DOMURL = window.URL || window.webkitURL || window; | |
| var context = d3.select("canvas").node().getContext('2d'); | |
| var img = new Image(); | |
| var data = new XMLSerializer().serializeToString(d3.select("svg.rasterize").node()); | |
| var svg = new Blob([data], {type: 'image/svg+xml;charset=utf-8'}); | |
| var url = DOMURL.createObjectURL(svg); | |
| img.onload = function () { | |
| context.drawImage(img, 0, 0); | |
| var dataURL = d3.select("canvas").node().toDataURL(); | |
| d3.select(".right").data([0,0,0,0]) | |
| .enter().append("img") | |
| .attr("src", dataURL) | |
| DOMURL.revokeObjectURL(url); | |
| } | |
| img.src = url; | |
| } | |
| </script> | |
| <body onload="makeViz()"> | |
| <div class="left"></div> | |
| <div class="right"></div> | |
| <footer> | |
| <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script> | |
| </footer> | |
| </body> | |
| </html> |
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Is this helpful https://gist.github.com/biovisualize/8187844?