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Last active November 30, 2015 01:33
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D3byEX 10.9: Sankey Diagram
Raw
index.html
<!DOCTYPE html>
<html>
<head>
<meta name="description" content="D3byEX 10.9" />
<meta charset="utf-8">
</head>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="sankey.js"></script>
<script>
var url = 'https://gist.githubusercontent.com/d3byex/25129228aa50c30ef01f/raw/e6ea7c4728e45fb8d0464b21686eec806687e117/sankey.json';
d3.json(url, function (error, data) {
var width = 950, height = 500;
var svg = d3.select('body')
.append('svg')
.attr({
width: width,
height: height
});
var mainGroup = svg.append('g');
var sankey = d3.sankey()
.nodeWidth(36)
.nodePadding(40)
.size([width, height])
.nodes(data.nodes)
.links(data.links)
.layout(10);
mainGroup.append('g')
.selectAll('g.link')
.data(data.links)
.enter()
.append('path')
.attr({
d: sankey.link(),
fill: 'none',
stroke: '#000',
'stroke-opacity': 0.2,
'stroke-width': function (d) { return Math.max(1, d.dy) }
})
.sort(function (a, b) { return b.dy - a.dy; });
var nodes = mainGroup.append('g')
.selectAll('g.node')
.data(data.nodes)
.enter()
.append('g')
.attr('transform', function (d) {
return 'translate(' + d.x + ',' + d.y + ')';
});
var color = d3.scale.category20();
nodes.append('rect')
.attr({
height: function (d) { return d.dy; },
width: sankey.nodeWidth(),
fill: function (d, i) {
return d.color = color(i);
},
stroke: 'black'
});
nodes.append('text')
.attr({
x: -6,
y: function (d) { return d.dy / 2; },
dy: '.35em',
'text-anchor': 'end'
})
.style('font', '10px sans-serif')
.text(function (d) { return d.name; })
.filter(function (d) { return d.x < width / 2; })
.attr({
x: 6 + sankey.nodeWidth(),
'text-anchor': 'start'
});
});
</script>
</body>
</html>
Raw
sankey.js
d3.sankey = function () {
var sankey = {},
nodeWidth = 24,
nodePadding = 8,
size = [1, 1],
nodes = [],
links = [];
sankey.nodeWidth = function (_) {
if (!arguments.length) return nodeWidth;
nodeWidth = +_;
return sankey;
};
sankey.nodePadding = function (_) {
if (!arguments.length) return nodePadding;
nodePadding = +_;
return sankey;
};
sankey.nodes = function (_) {
if (!arguments.length) return nodes;
nodes = _;
return sankey;
};
sankey.links = function (_) {
if (!arguments.length) return links;
links = _;
return sankey;
};
sankey.size = function (_) {
if (!arguments.length) return size;
size = _;
return sankey;
};
sankey.layout = function (iterations) {
computeNodeLinks();
computeNodeValues();
computeNodeBreadths();
computeNodeDepths(iterations);
computeLinkDepths();
return sankey;
};
sankey.relayout = function () {
computeLinkDepths();
return sankey;
};
sankey.link = function () {
var curvature = .5;
function link(d) {
var x0 = d.source.x + d.source.dx,
x1 = d.target.x,
xi = d3.interpolateNumber(x0, x1),
x2 = xi(curvature),
x3 = xi(1 - curvature),
y0 = d.source.y + d.sy + d.dy / 2,
y1 = d.target.y + d.ty + d.dy / 2;
return "M" + x0 + "," + y0
+ "C" + x2 + "," + y0
+ " " + x3 + "," + y1
+ " " + x1 + "," + y1;
}
link.curvature = function (_) {
if (!arguments.length) return curvature;
curvature = +_;
return link;
};
return link;
};
// Populate the sourceLinks and targetLinks for each node.
// Also, if the source and target are not objects, assume they are indices.
function computeNodeLinks() {
nodes.forEach(function (node) {
node.sourceLinks = [];
node.targetLinks = [];
});
links.forEach(function (link) {
var source = link.source,
target = link.target;
if (typeof source === "number") source = link.source = nodes[link.source];
if (typeof target === "number") target = link.target = nodes[link.target];
source.sourceLinks.push(link);
target.targetLinks.push(link);
});
}
// Compute the value (size) of each node by summing the associated links.
function computeNodeValues() {
nodes.forEach(function (node) {
node.value = Math.max(
d3.sum(node.sourceLinks, value),
d3.sum(node.targetLinks, value)
);
});
}
// Iteratively assign the breadth (x-position) for each node.
// Nodes are assigned the maximum breadth of incoming neighbors plus one;
// nodes with no incoming links are assigned breadth zero, while
// nodes with no outgoing links are assigned the maximum breadth.
function computeNodeBreadths() {
var remainingNodes = nodes,
nextNodes,
x = 0;
while (remainingNodes.length) {
nextNodes = [];
remainingNodes.forEach(function (node) {
node.x = x;
node.dx = nodeWidth;
node.sourceLinks.forEach(function (link) {
if (nextNodes.indexOf(link.target) < 0) {
nextNodes.push(link.target);
}
});
});
remainingNodes = nextNodes;
++x;
}
//
moveSinksRight(x);
scaleNodeBreadths((size[0] - nodeWidth) / (x - 1));
}
function moveSourcesRight() {
nodes.forEach(function (node) {
if (!node.targetLinks.length) {
node.x = d3.min(node.sourceLinks, function (d) { return d.target.x; }) - 1;
}
});
}
function moveSinksRight(x) {
nodes.forEach(function (node) {
if (!node.sourceLinks.length) {
node.x = x - 1;
}
});
}
function scaleNodeBreadths(kx) {
nodes.forEach(function (node) {
node.x *= kx;
});
}
function computeNodeDepths(iterations) {
var nodesByBreadth = d3.nest()
.key(function (d) { return d.x; })
.sortKeys(d3.ascending)
.entries(nodes)
.map(function (d) { return d.values; });
//
initializeNodeDepth();
resolveCollisions();
for (var alpha = 1; iterations > 0; --iterations) {
relaxRightToLeft(alpha *= .99);
resolveCollisions();
relaxLeftToRight(alpha);
resolveCollisions();
}
function initializeNodeDepth() {
var ky = d3.min(nodesByBreadth, function (nodes) {
return (size[1] - (nodes.length - 1) * nodePadding) / d3.sum(nodes, value);
});
nodesByBreadth.forEach(function (nodes) {
nodes.forEach(function (node, i) {
node.y = i;
node.dy = node.value * ky;
});
});
links.forEach(function (link) {
link.dy = link.value * ky;
});
}
function relaxLeftToRight(alpha) {
nodesByBreadth.forEach(function (nodes, breadth) {
nodes.forEach(function (node) {
if (node.targetLinks.length) {
var y = d3.sum(node.targetLinks, weightedSource) / d3.sum(node.targetLinks, value);
node.y += (y - center(node)) * alpha;
}
});
});
function weightedSource(link) {
return center(link.source) * link.value;
}
}
function relaxRightToLeft(alpha) {
nodesByBreadth.slice().reverse().forEach(function (nodes) {
nodes.forEach(function (node) {
if (node.sourceLinks.length) {
var y = d3.sum(node.sourceLinks, weightedTarget) / d3.sum(node.sourceLinks, value);
node.y += (y - center(node)) * alpha;
}
});
});
function weightedTarget(link) {
return center(link.target) * link.value;
}
}
function resolveCollisions() {
nodesByBreadth.forEach(function (nodes) {
var node,
dy,
y0 = 0,
n = nodes.length,
i;
// Push any overlapping nodes down.
nodes.sort(ascendingDepth);
for (i = 0; i < n; ++i) {
node = nodes[i];
dy = y0 - node.y;
if (dy > 0) node.y += dy;
y0 = node.y + node.dy + nodePadding;
}
// If the bottommost node goes outside the bounds, push it back up.
dy = y0 - nodePadding - size[1];
if (dy > 0) {
y0 = node.y -= dy;
// Push any overlapping nodes back up.
for (i = n - 2; i >= 0; --i) {
node = nodes[i];
dy = node.y + node.dy + nodePadding - y0;
if (dy > 0) node.y -= dy;
y0 = node.y;
}
}
});
}
function ascendingDepth(a, b) {
return a.y - b.y;
}
}
function computeLinkDepths() {
nodes.forEach(function (node) {
node.sourceLinks.sort(ascendingTargetDepth);
node.targetLinks.sort(ascendingSourceDepth);
});
nodes.forEach(function (node) {
var sy = 0, ty = 0;
node.sourceLinks.forEach(function (link) {
link.sy = sy;
sy += link.dy;
});
node.targetLinks.forEach(function (link) {
link.ty = ty;
ty += link.dy;
});
});
function ascendingSourceDepth(a, b) {
return a.source.y - b.source.y;
}
function ascendingTargetDepth(a, b) {
return a.target.y - b.target.y;
}
}
function center(node) {
return node.y + node.dy / 2;
}
function value(link) {
return link.value;
}
return sankey;
};
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