<!DOCTYPE html>
<html>
<head>
<script src="http://d3js.org/d3.v3.min.js"></script>
<meta charset="utf-8">
<title>JS Bin</title>
<style>
line.node-link, path.node-link {
fill: none;
stroke: black
}
circle.node {
fill: white;
stroke: black
}
circle.node+text {
text-anchor: middle;
}
text {
font-family: sans-serif;
pointer-events: none;
}
</style>
</head>
<body>
<script type="text/javascript">
// number of random nodes (gets crowded at >25 unless you change node diameter)
var num = 20;
// returns random int between 0 and num
function getRandomInt() {return Math.floor(Math.random() * (num));}
// nodes returns a [list] of {id: 1, fixed:true}
var nodes = d3.range(num).map(function(d) { return {id: d}; });
// links returns a [list] of {source: 0, target: 1} (values refer to indicies of nodes)
var links = d3.range(num).map(function(d) { return {source: getRandomInt(), target: getRandomInt()}; });
var width = 500,
height = 500;
var force = d3.layout.force()
.nodes(nodes)
.links(links)
.size([width, height]);
// evenly spaces nodes along arc
var circleCoord = function(node, index, num_nodes){
var circumference = circle.node().getTotalLength();
var pointAtLength = function(l){return circle.node().getPointAtLength(l)};
var sectionLength = (circumference)/num_nodes;
var position = sectionLength*index+sectionLength/2;
return pointAtLength(circumference-position)
}
// fades out lines that aren't connected to node d
var is_connected = function(d, opacity) {
lines.transition().style("stroke-opacity", function(o) {
return o.source === d || o.target === d ? 1 : opacity;
});
}
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
// invisible circle for placing nodes
// it's actually two arcs so we can use the getPointAtLength() and getTotalLength() methods
var dim = width-80
var circle = svg.append("path")
.attr("d", "M 40, "+(dim/2+40)+" a "+dim/2+","+dim/2+" 0 1,0 "+dim+",0 a "+dim/2+","+dim/2+" 0 1,0 "+dim*-1+",0")
.style("fill", "#f5f5f5");
force.start();
// set coordinates for container nodes
nodes.forEach(function(n, i) {
var coord = circleCoord(n, i, nodes.length)
n.x = coord.x
n.y = coord.y
});
// use this one for straight line links...
// var lines = svg.selectAll("line.node-link")
// .data(links).enter().append("line")
// .attr("class", "node-link")
// .attr("x1", function(d) { return d.source.x; })
// .attr("y1", function(d) { return d.source.y; })
// .attr("x2", function(d) { return d.target.x; })
// .attr("y2", function(d) { return d.target.y; });
// ...or use this one for curved line links
var lines = svg.selectAll("path.node-link")
.data(links).enter().append("path")
.attr("class", "node-link")
.attr("d", function(d) {
var dx = d.target.x - d.source.x,
dy = d.target.y - d.source.y,
dr = Math.sqrt(dx * dx + dy * dy);
return "M" +
d.source.x + "," +
d.source.y + "A" +
dr + "," + dr + " 0 0,1 " +
d.target.x + "," +
d.target.y;
});
var gnodes = svg.selectAll('g.gnode')
.data(nodes).enter().append('g')
.attr("transform", function(d) {
return "translate("+d.x+","+d.y+")"
})
.classed('gnode', true);
var node = gnodes.append("circle")
.attr("r", 25)
.attr("class", "node")
.on("mouseenter", function(d) {
is_connected(d, 0.1)
node.transition().duration(100).attr("r", 25)
d3.select(this).transition().duration(100).attr("r", 30)
})
.on("mouseleave", function(d) {
node.transition().duration(100).attr("r", 25);
is_connected(d, 1);
});
var labels = gnodes.append("text")
.attr("dy", 4)
.text(function(d){return d.id})
</script>
</body>
</html>