Tree Layout Orientations

In response to a Stack Overflow question, Tree drawing orientation.

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  font: 10px sans-serif;
}

.link {
  fill: none;
  stroke: #000;
}

.border {
  fill: none;
  shape-rendering: crispEdges;
  stroke: #aaa;
}

.node {
  stroke: #fff;
}

</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 140, right: 10, bottom: 140, left: 10},
    width = 240 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var svg = d3.select("body").selectAll("svg")
    .data(d3.entries(orientations))
  .enter().append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

svg.append("rect")
    .attr("width", width)
    .attr("height", height)
    .attr("class", "border");

svg.append("text")
    .attr("x", 6)
    .attr("y", 6)
    .attr("dy", ".71em")
    .text(function(d) { return d.key; });

d3.json("graph.json", function(error, root) {
  if (error) throw error;

svg.each(function(orientation) {
    var svg = d3.select(this),
        o = orientation.value;

// Compute the layout.
    var tree = d3.layout.tree().size(o.size),
        nodes = tree.nodes(root),
        links = tree.links(nodes);

// Create the link lines.
    svg.selectAll(".link")
        .data(links)
      .enter().append("path")
        .attr("class", "link")
        .attr("d", d3.svg.diagonal().projection(function(d) { return [o.x(d), o.y(d)]; }));

// Create the node circles.
    svg.selectAll(".node")
        .data(nodes)
      .enter().append("circle")
        .attr("class", "node")
        .attr("r", 4.5)
        .attr("cx", o.x)
        .attr("cy", o.y);
  });
});

</script>

https://d3js.org/d3.v3.min.js