printing protovis output (programmatically)

Question

I'm pondering switching to protovis for visualizations. One thing that keeps me skeptical however - since protovis creates its output as a div in a browser, I wonder if there is any at least semi-automatic way for me to create a bunch of images at once without opening each one and pressing "print" manually.

So the question would be:

• do you think I can use a browserless JS engine like V8 to execute the code and print the result?
• can I automate opening and printing within a browser?
• is there another way to get automated images from protovis?

Thanks, Nicolas

Answer 1

Have a look at this Google Groups thread about this very topic.

Answer 2

Check out http://www.phantomjs.org/

It is a headless browser.

It can do exactly what you want : http://code.google.com/p/phantomjs/wiki/QuickStart#Rendering

rasterize.js:

if (phantom.state.length === 0) {
    if (phantom.args.length !== 2) {
        console.log('Usage: rasterize.js URL filename');
        phantom.exit();
    } else {
        var address = phantom.args[0];
        phantom.state = 'rasterize';
        phantom.viewportSize = { width: 600, height: 600 };
        phantom.open(address);
    }
} else {
    var output = phantom.args[1];
    phantom.sleep(200);
    phantom.render(output);
    phantom.exit();
}

An example to produce the rendering of the famous Tiger (from SVG):

phantomjs rasterize.js http://ariya.github.com/svg/tiger.svg tiger.png