PMeinshausen/course.json

## course.json
{
    "name": "Gov 2001",
    "children": [
        {
            "name": "The Basics",
            "children": [
                {
                    "url": "http://projects.iq.harvard.edu/gov2001",
                    "name": "Course Overview",
                    "size": 104,
                    "value": 15.6443908991413725
                },
                {
                    "url": "http://projects.iq.harvard.edu/gov2001",
                    "name": "Introductory Statistics",
                    "size": 3250,
                    "value": 15.086410275323782
                }
            ]
        },{
            "name": "Theories of Inference",
            "children": [
                {
                    "url": "http://projects.iq.harvard.edu/gov2001",
                    "name": "Problems of Inference",
                    "size": 1279,
                    "value": 7.153833801578843
                },
                {
                    "url": "http://projects.iq.harvard.edu/gov2001",
                    "name": "Likelihood",
                    "size": 2582,
                    "value": 7.856319571406588
                },
                {
                    "url": "http://projects.iq.harvard.edu/gov2001",
                    "name": "Other Theories",
                    "size": 5164,
                    "value": 8.549466751966532
                }
            ]
        },{
            "name": "Maximum Likelihood Estimation",
            "children": [
                {
                    "url": "http://projects.iq.harvard.edu/gov2001",
                    "name": "Problem Sets",
                    "size": 59,
                    "value": 10.07753744390572
                },
                {
                    "url": "http://projects.iq.harvard.edu/gov2001",
                    "name": "Lectures",
                    "size": 317,
                    "value": 10.75890177387728
                }
            ]
        }
  ]
}

## index.html
<!DOCTYPE html>
<meta charset="utf-8">
<title>Gov 2001 Course Map</title>

    <style>

    #chart {
      width: 820px;
			height: 700px;
			background: #bbb;
			margin: 1px auto;
			position: relative;
			-webkit-box-sizing: border-box;
				-moz-box-sizing: border-box;
					box-sizing: border-box;
		}

		text {
			pointer-events: none;
		}

		.grandparent text { /* header text */
			font-weight: bold;
			font-size: large;
			font-family: "Open Sans", Helvetica, Arial, sans-serif;
		}

		rect {
			fill: none;
			stroke: #fff;
		}

		rect.parent,
		.grandparent rect {
			stroke-width: 2px;
		}

		.grandparent rect {
			fill: #fff;
		}

		.children rect.parent,
		.grandparent rect {
			cursor: pointer;
		}

		rect.parent {
			pointer-events: all;
		}

		.children:hover rect.child,
		.grandparent:hover rect {
			fill: #aaa;
		}

		.textdiv { /* text in the boxes */
			font-size: large;
			padding: 5px;
			font-family: "Open Sans", Helvetica, Arial, sans-serif;
		}

	</style>

<p id="chart">

<script src="http://d3js.org/d3.v2.js"></script>
<script src="http://code.jquery.com/jquery-1.7.1.js"></script>
<script>

	/*
	* If running inside bl.ocks.org we want to resize the iframe to fit both graphs
	* This bit of code was shared originally at https://gist.github.com/benjchristensen/2657838
	*/
	 if(parent.document.getElementsByTagName("iframe")[0]) {
			 parent.document.getElementsByTagName("iframe")[0].setAttribute('style', 'height: 700px !important');
		 }

	var margin = {top: 20, right: 0, bottom: 0, left: 0},
	width = 820,
	height = 700 - margin.top - margin.bottom,
	formatNumber = d3.format(",d"),
	transitioning;

	/* create x and y scales */
	var x = d3.scale.linear()
		.domain([0, width])
		.range([0, width]);

	var y = d3.scale.linear()
		.domain([0, height])
		.range([0, height]);

	var treemap = d3.layout.treemap()
		.children(function(d, depth) { return depth ? null : d.children; })
		.sort(function(a, b) { return a.value - b.value; })
		.ratio(height / width * 0.5 * (1 + Math.sqrt(5)))
		.round(false);

	/* create svg */
	var svg = d3.select("#chart").append("svg")
		.attr("width", width + margin.left + margin.right)
		.attr("height", height + margin.bottom + margin.top)
		.style("margin-left", -margin.left + "px")
		.style("margin.right", -margin.right + "px")
		.append("g")
		.attr("transform", "translate(" + margin.left + "," + margin.top + ")")
		.style("shape-rendering", "crispEdges");

	var color = d3.scale.category20c();

	var grandparent = svg.append("g")
		.attr("class", "grandparent");

	grandparent.append("rect")
		.attr("y", -margin.top)
		.attr("width", width)
		.attr("height", margin.top);

	grandparent.append("text")
		.attr("x", 6)
		.attr("y", 6 - margin.top)
		.attr("dy", ".75em");

	/* load in data, display root */
	d3.json("course.json", function(root) {

		initialize(root);
		accumulate(root);
		layout(root);
		display(root);

		function initialize(root) {
			root.x = root.y = 0;
			root.dx = width;
			root.dy = height;
			root.depth = 0;
		}

		// Aggregate the values for internal nodes. This is normally done by the
		// treemap layout, but not here because of the custom implementation.
		function accumulate(d) {
			return d.children
			? d.value = d.children.reduce(function(p, v) { return p + accumulate(v); }, 0)
			: d.value;
			}

		// Compute the treemap layout recursively such that each group of siblings
		// uses the same size (1×1) rather than the dimensions of the parent cell.
		// This optimizes the layout for the current zoom state. Note that a wrapper
		// object is created for the parent node for each group of siblings so that
		// the parent’s dimensions are not discarded as we recurse. Since each group
		// of sibling was laid out in 1×1, we must rescale to fit using absolute
		// coordinates. This lets us use a viewport to zoom.
		function layout(d) {
			if (d.children) {
			treemap.nodes({children: d.children});
			d.children.forEach(function(c) {
			c.x = d.x + c.x * d.dx;
			c.y = d.y + c.y * d.dy;
			c.dx *= d.dx;
			c.dy *= d.dy;
			c.parent = d;
			layout(c);
			});
			}
		}

		/* display shows the treemap and writes the embedded transition function */
		function display(d) {
			/* create grandparent bar at top */
			grandparent
				.datum(d.parent)
				.on("click", transition)
				.select("text")
				.text(name(d));

			var g1 = svg.insert("g", ".grandparent")
				.datum(d)
				.attr("class", "depth");

			/* add in data */
			var g = g1.selectAll("g")
				.data(d.children)
				.enter().append("g");


			/* transition on child click */
			g.filter(function(d) { return d.children; })
				.classed("children", true)
				.on("click", transition);

			/* write children rectangles */
			g.selectAll(".child")
				.data(function(d) { return d.children || [d]; })
				.enter().append("rect")
				   .attr("class", "child")
				   .call(rect)
				   .append("title")
				   .text(function(d) { return d.name + " " + formatNumber(d.size); });


			/* write parent rectangle */
			g.append("rect")
				.attr("class", "parent")
				.call(rect)
				/* open new window based on the json's URL value for leaf nodes */
				/* Chrome displays this on top */
				.on("click", function(d) {
					if(!d.children){
						window.open(d.url);
					}
				})
				.append("title")
				.text(function(d) { return d.name + " " + formatNumber(d.size); }); /*should be d.value*/


			/* Adding a foreign object instead of a text object, allows for text wrapping */
			g.append("foreignObject")
				.call(rect)
				/* open new window based on the json's URL value for leaf nodes */
				/* Firefox displays this on top */
				.on("click", function(d) {
					if(!d.children){
						window.open(d.url);
				}
			})
				.attr("class","foreignobj")
				.append("xhtml:div")
				.attr("dy", ".75em")
				.html(function(d) { return d.name;
				})
				.attr("class","textdiv"); //textdiv class allows us to style the text easily with CSS

			/* create transition function for transitions */
			function transition(d) {
				if (transitioning || !d) return;
				transitioning = true;

				var g2 = display(d),
				t1 = g1.transition().duration(750),
				t2 = g2.transition().duration(750);

				// Update the domain only after entering new elements.
				x.domain([d.x, d.x + d.dx]);
				y.domain([d.y, d.y + d.dy]);

				// Enable anti-aliasing during the transition.
				svg.style("shape-rendering", null);

				// Draw child nodes on top of parent nodes.
				svg.selectAll(".depth").sort(function(a, b) { return a.depth - b.depth; });

				// Fade-in entering text.
				g2.selectAll("text").style("fill-opacity", 0);
				g2.selectAll("foreignObject div").style("display", "none"); /*added*/

				// Transition to the new view.
				t1.selectAll("text").call(text).style("fill-opacity", 0);
				t2.selectAll("text").call(text).style("fill-opacity", 1);
				t1.selectAll("rect").call(rect);
				t2.selectAll("rect").call(rect);

				t1.selectAll(".textdiv").style("display", "none"); /* added */
				t1.selectAll(".foreignobj").call(foreign); /* added */
				t2.selectAll(".textdiv").style("display", "block"); /* added */
				t2.selectAll(".foreignobj").call(foreign); /* added */

				// Remove the old node when the transition is finished.
				t1.remove().each("end", function() {
				svg.style("shape-rendering", "crispEdges");
				transitioning = false;
				});

			}//endfunc transition

			return g;
		}//endfunc display

		function text(text) {
			text.attr("x", function(d) { return x(d.x) + 6; })
			.attr("y", function(d) { return y(d.y) + 6; });
		}


		function rect(rect) {
			rect.attr("x", function(d) { return x(d.x); })
			.attr("y", function(d) { return y(d.y); })
			.attr("width", function(d) { return x(d.x + d.dx) - x(d.x); })
			.attr("height", function(d) { return y(d.y + d.dy) - y(d.y); })
			.style("background", function(d) { return d.parent ? color(d.name) : null; });
		}

		function foreign(foreign){ /* added */
			foreign.attr("x", function(d) { return x(d.x); })
			.attr("y", function(d) { return y(d.y); })
			.attr("width", function(d) { return x(d.x + d.dx) - x(d.x); })
			.attr("height", function(d) { return y(d.y + d.dy) - y(d.y); });
		}

		function name(d) {
			return d.parent
			? name(d.parent) + "." + d.name
			: d.name;
			}
		});

</script>
	{
	"name": "Gov 2001",
	"children": [
	{
	"name": "The Basics",
	"children": [
	{
	"url": "http://projects.iq.harvard.edu/gov2001",
	"name": "Course Overview",
	"size": 104,
	"value": 15.6443908991413725
	},
	{
	"url": "http://projects.iq.harvard.edu/gov2001",
	"name": "Introductory Statistics",
	"size": 3250,
	"value": 15.086410275323782
	}
	]
	},{
	"name": "Theories of Inference",
	"children": [
	{
	"url": "http://projects.iq.harvard.edu/gov2001",
	"name": "Problems of Inference",
	"size": 1279,
	"value": 7.153833801578843
	},
	{
	"url": "http://projects.iq.harvard.edu/gov2001",
	"name": "Likelihood",
	"size": 2582,
	"value": 7.856319571406588
	},
	{
	"url": "http://projects.iq.harvard.edu/gov2001",
	"name": "Other Theories",
	"size": 5164,
	"value": 8.549466751966532
	}
	]
	},{
	"name": "Maximum Likelihood Estimation",
	"children": [
	{
	"url": "http://projects.iq.harvard.edu/gov2001",
	"name": "Problem Sets",
	"size": 59,
	"value": 10.07753744390572
	},
	{
	"url": "http://projects.iq.harvard.edu/gov2001",
	"name": "Lectures",
	"size": 317,
	"value": 10.75890177387728
	}
	]
	}
	]
	}
	<!DOCTYPE html>
	<meta charset="utf-8">
	<title>Gov 2001 Course Map</title>

	<style>

	#chart {
	width: 820px;
	height: 700px;
	background: #bbb;
	margin: 1px auto;
	position: relative;
	-webkit-box-sizing: border-box;
	-moz-box-sizing: border-box;
	box-sizing: border-box;
	}

	text {
	pointer-events: none;
	}

	.grandparent text { /* header text */
	font-weight: bold;
	font-size: large;
	font-family: "Open Sans", Helvetica, Arial, sans-serif;
	}

	rect {
	fill: none;
	stroke: #fff;
	}

	rect.parent,
	.grandparent rect {
	stroke-width: 2px;
	}

	.grandparent rect {
	fill: #fff;
	}

	.children rect.parent,
	.grandparent rect {
	cursor: pointer;
	}

	rect.parent {
	pointer-events: all;
	}

	.children:hover rect.child,
	.grandparent:hover rect {
	fill: #aaa;
	}

	.textdiv { /* text in the boxes */
	font-size: large;
	padding: 5px;
	font-family: "Open Sans", Helvetica, Arial, sans-serif;
	}

	</style>

	<p id="chart">

	<script src="http://d3js.org/d3.v2.js"></script>
	<script src="http://code.jquery.com/jquery-1.7.1.js"></script>
	<script>

	/*
	* If running inside bl.ocks.org we want to resize the iframe to fit both graphs
	* This bit of code was shared originally at https://gist.github.com/benjchristensen/2657838
	*/
	if(parent.document.getElementsByTagName("iframe")[0]) {
	parent.document.getElementsByTagName("iframe")[0].setAttribute('style', 'height: 700px !important');
	}

	var margin = {top: 20, right: 0, bottom: 0, left: 0},
	width = 820,
	height = 700 - margin.top - margin.bottom,
	formatNumber = d3.format(",d"),
	transitioning;

	/* create x and y scales */
	var x = d3.scale.linear()
	.domain([0, width])
	.range([0, width]);

	var y = d3.scale.linear()
	.domain([0, height])
	.range([0, height]);

	var treemap = d3.layout.treemap()
	.children(function(d, depth) { return depth ? null : d.children; })
	.sort(function(a, b) { return a.value - b.value; })
	.ratio(height / width * 0.5 * (1 + Math.sqrt(5)))
	.round(false);

	/* create svg */
	var svg = d3.select("#chart").append("svg")
	.attr("width", width + margin.left + margin.right)
	.attr("height", height + margin.bottom + margin.top)
	.style("margin-left", -margin.left + "px")
	.style("margin.right", -margin.right + "px")
	.append("g")
	.attr("transform", "translate(" + margin.left + "," + margin.top + ")")
	.style("shape-rendering", "crispEdges");

	var color = d3.scale.category20c();

	var grandparent = svg.append("g")
	.attr("class", "grandparent");

	grandparent.append("rect")
	.attr("y", -margin.top)
	.attr("width", width)
	.attr("height", margin.top);

	grandparent.append("text")
	.attr("x", 6)
	.attr("y", 6 - margin.top)
	.attr("dy", ".75em");

	/* load in data, display root */
	d3.json("course.json", function(root) {

	initialize(root);
	accumulate(root);
	layout(root);
	display(root);

	function initialize(root) {
	root.x = root.y = 0;
	root.dx = width;
	root.dy = height;
	root.depth = 0;
	}

	// Aggregate the values for internal nodes. This is normally done by the
	// treemap layout, but not here because of the custom implementation.
	function accumulate(d) {
	return d.children
	? d.value = d.children.reduce(function(p, v) { return p + accumulate(v); }, 0)
	: d.value;
	}

	// Compute the treemap layout recursively such that each group of siblings
	// uses the same size (1×1) rather than the dimensions of the parent cell.
	// This optimizes the layout for the current zoom state. Note that a wrapper
	// object is created for the parent node for each group of siblings so that
	// the parent’s dimensions are not discarded as we recurse. Since each group
	// of sibling was laid out in 1×1, we must rescale to fit using absolute
	// coordinates. This lets us use a viewport to zoom.
	function layout(d) {
	if (d.children) {
	treemap.nodes({children: d.children});
	d.children.forEach(function(c) {
	c.x = d.x + c.x * d.dx;
	c.y = d.y + c.y * d.dy;
	c.dx *= d.dx;
	c.dy *= d.dy;
	c.parent = d;
	layout(c);
	});
	}
	}

	/* display shows the treemap and writes the embedded transition function */
	function display(d) {
	/* create grandparent bar at top */
	grandparent
	.datum(d.parent)
	.on("click", transition)
	.select("text")
	.text(name(d));

	var g1 = svg.insert("g", ".grandparent")
	.datum(d)
	.attr("class", "depth");

	/* add in data */
	var g = g1.selectAll("g")
	.data(d.children)
	.enter().append("g");



	/* transition on child click */
	g.filter(function(d) { return d.children; })
	.classed("children", true)
	.on("click", transition);

	/* write children rectangles */
	g.selectAll(".child")
	.data(function(d) { return d.children \|\| [d]; })
	.enter().append("rect")
	.attr("class", "child")
	.call(rect)
	.append("title")
	.text(function(d) { return d.name + " " + formatNumber(d.size); });


	/* write parent rectangle */
	g.append("rect")
	.attr("class", "parent")
	.call(rect)
	/* open new window based on the json's URL value for leaf nodes */
	/* Chrome displays this on top */
	.on("click", function(d) {
	if(!d.children){
	window.open(d.url);
	}
	})
	.append("title")
	.text(function(d) { return d.name + " " + formatNumber(d.size); }); /should be d.value/


	/* Adding a foreign object instead of a text object, allows for text wrapping */
	g.append("foreignObject")
	.call(rect)
	/* open new window based on the json's URL value for leaf nodes */
	/* Firefox displays this on top */
	.on("click", function(d) {
	if(!d.children){
	window.open(d.url);
	}
	})
	.attr("class","foreignobj")
	.append("xhtml:div")
	.attr("dy", ".75em")
	.html(function(d) { return d.name;
	})
	.attr("class","textdiv"); //textdiv class allows us to style the text easily with CSS

	/* create transition function for transitions */
	function transition(d) {
	if (transitioning \|\| !d) return;
	transitioning = true;

	var g2 = display(d),
	t1 = g1.transition().duration(750),
	t2 = g2.transition().duration(750);

	// Update the domain only after entering new elements.
	x.domain([d.x, d.x + d.dx]);
	y.domain([d.y, d.y + d.dy]);

	// Enable anti-aliasing during the transition.
	svg.style("shape-rendering", null);

	// Draw child nodes on top of parent nodes.
	svg.selectAll(".depth").sort(function(a, b) { return a.depth - b.depth; });

	// Fade-in entering text.
	g2.selectAll("text").style("fill-opacity", 0);
	g2.selectAll("foreignObject div").style("display", "none"); /added/

	// Transition to the new view.
	t1.selectAll("text").call(text).style("fill-opacity", 0);
	t2.selectAll("text").call(text).style("fill-opacity", 1);
	t1.selectAll("rect").call(rect);
	t2.selectAll("rect").call(rect);

	t1.selectAll(".textdiv").style("display", "none"); /* added */
	t1.selectAll(".foreignobj").call(foreign); /* added */
	t2.selectAll(".textdiv").style("display", "block"); /* added */
	t2.selectAll(".foreignobj").call(foreign); /* added */

	// Remove the old node when the transition is finished.
	t1.remove().each("end", function() {
	svg.style("shape-rendering", "crispEdges");
	transitioning = false;
	});

	}//endfunc transition

	return g;
	}//endfunc display

	function text(text) {
	text.attr("x", function(d) { return x(d.x) + 6; })
	.attr("y", function(d) { return y(d.y) + 6; });
	}



	function rect(rect) {
	rect.attr("x", function(d) { return x(d.x); })
	.attr("y", function(d) { return y(d.y); })
	.attr("width", function(d) { return x(d.x + d.dx) - x(d.x); })
	.attr("height", function(d) { return y(d.y + d.dy) - y(d.y); })
	.style("background", function(d) { return d.parent ? color(d.name) : null; });
	}

	function foreign(foreign){ /* added */
	foreign.attr("x", function(d) { return x(d.x); })
	.attr("y", function(d) { return y(d.y); })
	.attr("width", function(d) { return x(d.x + d.dx) - x(d.x); })
	.attr("height", function(d) { return y(d.y + d.dy) - y(d.y); });
	}

	function name(d) {
	return d.parent
	? name(d.parent) + "." + d.name
	: d.name;
	}
	});

	</script>