Convert Raphael canvas inside div to PNG
Question
I've created an SVG using Raphael that I want to capture and convert to PNG and then display in the open window. I have looked at some other stack overflow answers like this one . I implemented ollieg's answer to that question. Here's an example of what I'm doing:
<html>
<head>
<script src="NBA_test/lib/raphael-min.js"></script>
</head>
<body>
<div id="canvas"></div><br>
<script language="JavaScript">
var test=Raphael("canvas",50,50);
var rect=test.rect(0,0,50,50);
rect.attr({fill: '#fff000'})
window.onload = function() {
var canvas = document.getElementById("canvas");
window.location = canvas.toDataURL("image/png");
}
</script>
</body>
</html>
This should draw a yellow rectangle and output it as a png. The console confirms that the SVG is being captured correctly in the canvas var. However, the toDataURL line throws an error: "TypeError: 'null' is not an object (evaluating 'canvas.toDataURL')" I know my example is a little different in the sense that I don't have an actual canvas tag in my html, just the div that is going to get the canvas. Given that the canvas is being captured correctly, however, I don't understand why the second line throws that error.
1 answers
solution1
0 ACCPTED 2014-06-24 19:04:32
Using canvg per the suggestion above and raphael.export.js , I have solved my problem (kind of). My minimal example now works as below:
<html>
<head>
<script src="lib/raphael-min.js"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/rgbcolor.js"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/StackBlur.js"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/canvg.js"></script>
<script src="lib/raphael.export.js"></script>
</head>
<body>
<div id="raph_canvas"></div><br>
<canvas id="html_canvas" width="50px" height="50px"></canvas>
<script language="JavaScript">
var test=Raphael("raph_canvas",50,50);
var rect=test.rect(0,0,50,50);
rect.attr({fill: '#fff000', 'fill-opacity':1, 'stroke-width':1})
window.onload = function() {
var canvas_svg = test.toSVG();
canvg('html_canvas',canvas_svg);
var canvas_html = document.getElementById("html_canvas");
window.location = canvas_html.toDataURL("image/png");
}
</script>
</body>
</html>
The problem now is that my actual app, which is a little more complex, doesn't work, but I will maybe post a separate question about that.
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