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@elipousson
Forked from mbostock/.block
Last active January 30, 2017 01:58
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Curved Links
license: gpl-3.0

This variation of a force-directed graph uses intermediate nodes in links to create aesthetically-pleasing Bézier curves.

<!DOCTYPE html>
<meta charset="utf-8">
<style>
.node {
stroke: #fff;
stroke-width: 1.5px;
}
.link {
fill: none;
stroke: #bbb;
}
</style>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var svg = d3.select("svg"),
width = +svg.attr("width"),
height = +svg.attr("height");
var color = d3.scaleOrdinal(d3.schemeCategory20);
var simulation = d3.forceSimulation()
.force("link", d3.forceLink().distance(10).strength(0.5))
.force("charge", d3.forceManyBody())
.force("center", d3.forceCenter(width / 2, height / 2));
d3.json("miserables.json", function(error, graph) {
if (error) throw error;
var nodes = graph.nodes,
nodeById = d3.map(nodes, function(d) { return d.id; }),
links = graph.links,
bilinks = [];
links.forEach(function(link) {
var s = link.source = nodeById.get(link.source),
t = link.target = nodeById.get(link.target),
i = {}; // intermediate node
nodes.push(i);
links.push({source: s, target: i}, {source: i, target: t});
bilinks.push([s, i, t]);
});
var link = svg.selectAll(".link")
.data(bilinks)
.enter().append("path")
.attr("class", "link");
var node = svg.selectAll(".node")
.data(nodes.filter(function(d) { return d.id; }))
.enter().append("circle")
.attr("class", "node")
.attr("r", 5)
.attr("fill", function(d) { return color(d.group); })
.call(d3.drag()
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended));
node.append("title")
.text(function(d) { return d.id; });
simulation
.nodes(nodes)
.on("tick", ticked);
simulation.force("link")
.links(links);
function ticked() {
link.attr("d", positionLink);
node.attr("transform", positionNode);
}
});
function positionLink(d) {
return "M" + d[0].x + "," + d[0].y
+ "S" + d[1].x + "," + d[1].y
+ " " + d[2].x + "," + d[2].y;
}
function positionNode(d) {
return "translate(" + d.x + "," + d.y + ")";
}
function dragstarted(d) {
if (!d3.event.active) simulation.alphaTarget(0.3).restart();
d.fx = d.x, d.fy = d.y;
}
function dragged(d) {
d.fx = d3.event.x, d.fy = d3.event.y;
}
function dragended(d) {
if (!d3.event.active) simulation.alphaTarget(0);
d.fx = null, d.fy = null;
}
</script>
{
"nodes": [{
"title": "Process Map Step 1",
"id": 0,
"x": 695,
"y": 100,
"eventTypeId": null
}, {
"title": "Process Map Step 2",
"id": 1,
"x": 770,
"y": 271,
"eventTypeId": null
}, {
"id": 2,
"title": "",
"x": 842,
"y": 93,
"eventTypeId": null
}, {
"id": 3,
"title": "",
"x": 769,
"y": 447,
"eventTypeId": null
}],
"links": [{
"source": 0,
"target": 1
}, {
"source": 2,
"target": 1
}, {
"source": 1,
"target": 3
}]
}
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