D3js: how to generate standalone SVG files? (Nodejs)

Here's a very short node script that will output an svg to stdout generated with d3.js.

#!/usr/bin/env node

var d3 = require("d3"),
    jsdom = require("jsdom").jsdom;

var body = d3.select(jsdom().documentElement).select("body");

var svg = body.append("svg");
process.stdout.write(body.node().innerHTML);

Link to snippet on bl.ocks.org


I recently wanted to do just that and asked a question here. I was pointed to phantomJS. Using PhantomJS, I created a JS -

svggen.js:

var page = require('webpage').create(),
    url = 'http://www.example.com/wordcloud.html';

page.open(url, function (status) {
    if (status !== 'success') {
        console.log('Unable to access network');
    } else {
        var svgData = page.evaluate(function(s){
                var serializer = new XMLSerializer();
                var element = document.getElementById("svg1");
                return serializer.serializeToString(element);
        });
        console.log("<?xml version=\"1.0\"?>"+svgData);
    }
    phantom.exit();
});

wordcloud.html:

<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="d3.min.js"></script>
<script src="d3.layout.cloud.js"></script>
<script>
  var fill = d3.scale.category20();

  d3.layout.cloud().size([500, 800])
      .words([
        "Hello", "world", "normally", "you", "want", "more", "words",
        "than", "this"].map(function(d) {
        return {text: d, size: 10 + Math.random() * 90};
      }))
      .padding(5)
      .rotate(function() { return ~~(Math.random() * 2) * 90; })
      .font("Impact")
      .fontSize(function(d) { return d.size; })
      .on("end", draw)
      .start();

  function draw(words) {
    d3.select("body").append("svg")
        .attr("width", 500)
        .attr("height", 800)
        .attr("id","svg1")
        .attr("xmlns","http://www.w3.org/2000/svg")
        .attr("xmlns:xlink","http://www.w3.org/1999/xlink")
      .append("g")
        .attr("transform", "translate(150,150)")
      .selectAll("text")
        .data(words)
      .enter().append("text")
        .style("font-size", function(d) { return d.size + "px"; })
        .style("font-family", "Impact")
        .style("fill", function(d, i) { return fill(i); })
        .attr("text-anchor", "middle")
        .attr("transform", function(d) {
          return "translate(" + [d.x, d.y] + ")rotate(" + d.rotate + ")";
        })
        .text(function(d) { return d.text; });
  }
</script>
</body></html>

Then I run 

phantomjs svggen.js > svgFile.svg

The resulting svgFile.svg is a standalone SVG File. For d3cloud check this.


Github repository svgcreator.node.js to try out.

D3 doesn't care at all what actually generate your SVG. The main problem with creating only SVG is that you can't have Javascript then, which of course means that you can't use D3. Apart from this fundamental no-no, there's nothing stopping you :)

Proof of concept: Inspired by the other answer, here's some proof-of-concept code using jsdom.

1. Install NodeJS (1).

curl http://npmjs.org/install.sh | sh       #this should work (not tested)

2. Install jsdom using the Node Packages Manager (2): 

$npm install jsdom

3. Wrap your D3js code within some jsdom code, paste into a jsdom.node.js file :

var jsdom = require('jsdom');

jsdom.env(
  "<html><body></body></html>",
  [ 'http://d3js.org/d3.v3.min.js' ],
  function (err, window) {
    var svg = window.d3.select("body")
        .append("svg")
        .attr("width", 100).attr("height", 100);

    svg.append("rect")
        .attr("x", 10)
        .attr("y", 10)
        .attr("width", 80)
        .attr("height", 80)
        .style("fill", "orange");
// PRINT OUT:
    console.log(window.d3.select("body").html());
//  fs.writeFileSync('out.svg', window.d3.select("body").html()); // or this
  }
);

4. Run in terminal 

$node jsdom.node.js > test.svg

The stdout output is the SVG, which is then injected into a test.svg file. Job done.

As Gilly points out in the comments, you may need version 3 of jsdom for this to work.

Tags:

Svg

Node.Js

D3.Js

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