D3.js and Octopress - Distributed Knowledge

This article is about how to use versatile D3.js with Octopress.

Recently I was looking for flow chart diagram or tree structure diagram, but I did not want to produce static image diagrams using Microsoft Vizio or similar softwares.

My requirement was to come up with tree structure data representation, which I could change in future unlike static pictures and can not be changed in future.

I found D3.js to be perfect for this scenario. Here, I store data in JSON file and I use D3.js to display that data according to my needs.

Challenge was how to fuse D3.js with Octopress.

First approcah to understand the D3.js from scratch but since I was short in time so I choose hacker way.

D3.js have long list of examples/gallery which are extremly helpful and powerful.

In this blog I am trying to incorporate this example.

Step 1

New post in Octopress created as .markdown file using

rake new_post [“D3.js and Octopress”]

This markdown file will now need to have have

CSS - D3.js related stylesheet code for styling
Javascript code - D3.js code to interpret data and bind with style sheet code
JSON data file - This is going to be data file apart from .markdown file

Step 2

JSON data file need to be placed in a folder from where it can be extracted when final html rendering is done.

I have choosen JSON file location to be

/assets/flare.json
d3.json(“/assets/flare.json”, function(json) {
Here, assets folder for octopress is
> octopress -> /source/assets

JSON file can be found here

In below code snippet confiure following parameters to customize height and width of tree

h = 650 - m[0] - m[2] (replace 650 with 800 for expanded tree)
// Normalize for fixed-depth.
nodes.forEach(function(d) { d.y = d.depth * 130; }); ===> (Use 180 instead of 130 for wider tree)

// Initialize the display to show a few nodes.
root.children.forEach(toggleAll);
toggle(root.children[1]);
toggle(root.children[1].children[2]);
toggle(root.children[5]); =====> Here is number of 1st level childs
toggle(root.children[5].children[0]);

[Update] To make each node a hyperlink comment following code and instead insert below code.
Make sure JSON file have a field name url

// nodeEnter.append(“svg:text”)
// .attr(“x”, function(d) { return d.children || d._children ? -10 : 10; })
// .attr(“dy”, “.35em”)
// .attr(“text-anchor”, function(d) { return d.children || d._children ? “end” : “start”;
// .text(function(d) { return d.name; })
// .style(“fill-opacity”, 1e-6);

nodeEnter.append(“svg:a”).attr(“xlink:href”, function(d) { return d.url; }).attr(“target”, “_blank”)
.append(“svg:text”).text(function(d) { return d.name; })
.attr(“x”, function(d) { return d.children || d._children ? -10 : 10; })
.attr(“dy”, “.35em”)
.attr(“text-anchor”, function(d) { return d.children || d._children ? “end” : “start”; })
.text(function(d) { return d.name; })
.style(“fill-opacity”, 1e-6);

Code for blog post (.markdown file) is as follows

D3.js and Octopress.markdown

<script src="http://d3js.org/d3.v3.min.js"></script>
<style type="text/css">
.node circle {
  cursor: pointer;
  fill: #fff;
  stroke: steelblue;
  stroke-width: 1.5px;
}

.node text {
  font-size: 11px;
}

path.link {
  fill: none;
  stroke: #ccc;
  stroke-width: 1.5px;
}

  </style>
  <style>

#chart, #header, #footer {
  position: absolute;
  top: 0;
}

#header.inverted, #footer.inverted {
  color: #fff;
  text-shadow: 0 1px 4px #000;
}


rect {
  fill: none;
  pointer-events: all;
}

line {
  stroke: #000;
  stroke-width: 1.5px;
}

.string, .regexp {
  color: #f39;
}

.keyword {
  color: #00c;
}

.comment {
  color: #777;
  font-style: oblique;
}

.number {
  color: #369;
}

.class, .special {
  color: #1181B8;
}

</style>

<body>
    <div id="body">              
        click or option-click to expand or collapse
    </div>
    <script type="text/javascript">

var m = [20, 120, 20, 120],
    w = 1280 - m[1] - m[3],
    h = 650 - m[0] - m[2],
    i = 0,
    root;

var tree = d3.layout.tree()
    .size([h, w]);

var diagonal = d3.svg.diagonal()
    .projection(function(d) { return [d.y, d.x]; });

var vis = d3.select("#body").append("svg:svg")
    .attr("width", w + m[1] + m[3])
    .attr("height", h + m[0] + m[2])
  .append("svg:g")
    .attr("transform", "translate(" + m[3] + "," + m[0] + ")");

d3.json("/assets/flare.json", function(json) {
  root = json;
  root.x0 = h / 2;
  root.y0 = 0;

  function toggleAll(d) {
    if (d.children) {
      d.children.forEach(toggleAll);
      toggle(d);
    }
  }

  // Initialize the display to show a few nodes.
  root.children.forEach(toggleAll);
  toggle(root.children[1]);
  toggle(root.children[1].children[2]);
  toggle(root.children[9]);
  toggle(root.children[9].children[0]);

  update(root);
});

function update(source) {
  var duration = d3.event && d3.event.altKey ? 5000 : 500;

  // Compute the new tree layout.
  var nodes = tree.nodes(root).reverse();

  // Normalize for fixed-depth.
  nodes.forEach(function(d) { d.y = d.depth * 130; });

  // Update the nodes…
  var node = vis.selectAll("g.node")
      .data(nodes, function(d) { return d.id || (d.id = ++i); });

  // Enter any new nodes at the parent's previous position.
  var nodeEnter = node.enter().append("svg:g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
      .on("click", function(d) { toggle(d); update(d); });

  nodeEnter.append("svg:circle")
      .attr("r", 1e-6)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeEnter.append("svg:text")
      .attr("x", function(d) { return d.children || d._children ? -10 : 10; })
      .attr("dy", ".35em")
      .attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
      .text(function(d) { return d.name; })
      .style("fill-opacity", 1e-6);

  // Transition nodes to their new position.
  var nodeUpdate = node.transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });

  nodeUpdate.select("circle")
      .attr("r", 4.5)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeUpdate.select("text")
      .style("fill-opacity", 1);

  // Transition exiting nodes to the parent's new position.
  var nodeExit = node.exit().transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
      .remove();

  nodeExit.select("circle")
      .attr("r", 1e-6);

  nodeExit.select("text")
      .style("fill-opacity", 1e-6);

  // Update the links…
  var link = vis.selectAll("path.link")
      .data(tree.links(nodes), function(d) { return d.target.id; });

  // Enter any new links at the parent's previous position.
  link.enter().insert("svg:path", "g")
      .attr("class", "link")
      .attr("d", function(d) {
        var o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});
      })
    .transition()
      .duration(duration)
      .attr("d", diagonal);

  // Transition links to their new position.
  link.transition()
      .duration(duration)
      .attr("d", diagonal);

  // Transition exiting nodes to the parent's new position.
  link.exit().transition()
      .duration(duration)
      .attr("d", function(d) {
        var o = {x: source.x, y: source.y};
        return diagonal({source: o, target: o});
      })
      .remove();

  // Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

// Toggle children.
function toggle(d) {
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
}

</script>
</body>

Demo
click or option-click to expand or collapse

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