oh no! now some of the link path gradients do not render 😱
sankey
.nodes(graph.nodes)
.links(graph.links)
.layout(14); // any value > 13 breaks the link gradientan iteration on by Patient Flow Sankey Particles from @micahstubbs
see also the working version with 13 layout iterations
inspired by the blog post Data-based and unique gradients for visualizations with d3.js and associated example Data based gradients - Simple - Solar system from @nadiehbremer
<!DOCTYPE html>
<meta charset='utf-8'>
<title>Sankey Gradients</title>
<script src='https://cdnjs.cloudflare.com/ajax/libs/d3/4.4.0/d3.min.js'></script>
<script src='d3.sankey.js'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.19.0/babel.min.js'></script>
<style>
.node rect {
cursor: move;
fill-opacity: .9;
shape-rendering: crispEdges;
}
.node text {
pointer-events: none;
font-family: Helvetica;
font-size: 12px;
}
</style>
<body>
<div id='chart'>
<script lang='babel' type='text/babel'>
const units = '';
const margin = {top: 10, right: 10, bottom: 10, left: 10};
const width = 960 - margin.left - margin.right;
const height = 300 - margin.top - margin.bottom;
// zero decimal places
const formatNumber = d3.format(',.0f');
const format = d => `${formatNumber(d)} ${units}`;
const color = d3.scaleOrdinal()
.domain([
'All referred patients',
'First consult outpatient clinic',
'OR-receipt',
'Start surgery',
// 'No OR-receipt',
// 'No emergency',
// 'No surgery',
'Emergency'
])
.range([
'#90eb9d',
'#f9d057',
'#f29e2e',
'#00ccbc',
'#d7191c'
]);
d3.select('#chart')
.style('visibility', 'visible');
// append the svg canvas to the page
const svg = d3.select('#chart').append('svg')
.attr('width', width + margin.left + margin.right)
.attr('height', height + margin.top + margin.bottom)
.append('g')
.attr('transform', `translate(${margin.left},${margin.top})`);
// set the sankey diagram properties
const sankey = d3.sankey()
.nodeWidth(12)
.nodePadding(10)
.size([width, height]);
const path = sankey.link();
// append a defs (for definition) element to your SVG
const defs = svg.append('defs');
// load the data
d3.json('data.json', (error, graph) => {
console.log('graph', graph);
sankey
.nodes(graph.nodes)
.links(graph.links)
.layout(14); // any value > 13 breaks the link gradient
// add in the links
const link = svg.append('g').selectAll('.link')
.data(graph.links)
.enter().append('path')
.attr('class', 'link')
.attr('d', path)
.style('stroke-width', d => Math.max(1, d.dy))
.style('fill', 'none')
.style('stroke-opacity', 0.18)
.sort((a, b) => b.dy - a.dy)
.on('mouseover', function() {
d3.select(this).style('stroke-opacity', 0.5);
})
.on('mouseout', function() {
d3.select(this).style('stroke-opacity', 0.2);
});
// add the link titles
link.append('title')
.text(d => `${d.source.name} → ${d.target.name}\n${format(d.value)}`);
// add in the nodes
const node = svg.append('g').selectAll('.node')
.data(graph.nodes)
.enter().append('g')
.attr('class', 'node')
.attr('transform', d => `translate(${d.x},${d.y})`)
.call(d3.drag()
.subject(d => d)
.on('start', function() {
this.parentNode.appendChild(this); })
.on('drag', dragmove));
// add the rectangles for the nodes
node.append('rect')
.attr('height', d => d.dy)
.attr('width', sankey.nodeWidth())
.style('fill', d => {
if(color.domain().indexOf(d.name) > -1){
return d.color = color(d.name);
} else {
return d.color = '#ccc';
}
})
.append('title')
.text(d => `${d.name}\n${format(d.value)}`);
// add in the title for the nodes
node.append('text')
.attr('x', -6)
.attr('y', d => d.dy / 2)
.attr('dy', '.35em')
.attr('text-anchor', 'end')
.attr('transform', null)
.text(d => d.name)
.filter(d => d.x < width / 2)
.attr('x', 6 + sankey.nodeWidth())
.attr('text-anchor', 'start');
// add gradient to links
link.style('stroke', (d, i) => {
console.log('d from gradient stroke func', d);
// make unique gradient ids
const gradientID = `gradient${i}`;
const startColor = d.source.color;
const stopColor = d.target.color;
console.log('startColor', startColor);
console.log('stopColor', stopColor);
const linearGradient = defs.append('linearGradient')
.attr('id', gradientID);
linearGradient.selectAll('stop')
.data([
{offset: '10%', color: startColor },
{offset: '90%', color: stopColor }
])
.enter().append('stop')
.attr('offset', d => {
console.log('d.offset', d.offset);
return d.offset;
})
.attr('stop-color', d => {
console.log('d.color', d.color);
return d.color;
});
return `url(#${gradientID})`;
})
// the function for moving the nodes
function dragmove(d) {
d3.select(this).attr('transform',
`translate(${d.x = Math.max(0, Math.min(width - d.dx, d3.event.x))},${d.y = Math.max(0, Math.min(height - d.dy, d3.event.y))})`);
sankey.relayout();
link.attr('d', path);
}
});
</script>
</body>
</html>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;
};{
"nodes": [
{
"name": "All referred patients",
"id": 0
},
{
"name": "First consult outpatient clinic",
"id": 1
},
{
"name": "No OR-receipt",
"id": 2
},
{
"name": "OR-receipt",
"id": 3
},
{
"name": "No surgery",
"id": 4
},
{
"name": "Start surgery",
"id": 5
},
{
"name": "Emergency",
"id": 6
},
{
"name": "No emergency",
"id": 7
}
],
"links": [
{
"source": 0,
"target": 1,
"value": 1,
"label": 1
},
{
"source": 1,
"target": 2,
"value": 0.64,
"label": 0.64
},
{
"source": 1,
"target": 3,
"value": 0.36,
"label": 0.36
},
{
"source": 3,
"target": 4,
"value": 0.1188,
"label": 0.33
},
{
"source": 3,
"target": 5,
"value": 0.2412,
"label": 0.67
},
{
"source": 5,
"target": 6,
"value": 0.038592,
"label": 0.16
},
{
"source": 5,
"target": 7,
"value": 0.20260799999999998,
"label": 0.84
}
]
}