Skip to content

Instantly share code, notes, and snippets.

@mbostock
Last active July 9, 2016 09:38
Show Gist options
  • Star 2 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save mbostock/aff9e559c5c9968b7ac6 to your computer and use it in GitHub Desktop.
Save mbostock/aff9e559c5c9968b7ac6 to your computer and use it in GitHub Desktop.
Arc Corners
license: gpl-3.0

In D3 3.5, you can generate rounded arcs with d3.svg.arc cornerRadius and separate adjacent arcs with d3.layout.pie padAngle. The schematic representation above shows the circles used to round the arcs’ corners.

<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>
var data = [1, 1, 2, 3, 5, 8, 13];
var width = 960,
height = 500,
outerRadius = height / 2 - 10,
innerRadius = outerRadius - 60,
cornerRadius = 12,
padAngle = .03;
var pie = d3.layout.pie()
.padAngle(padAngle);
var arcs = pie(data);
var arc = d3.svg.arc()
.innerRadius(innerRadius)
.outerRadius(outerRadius)
.cornerRadius(cornerRadius);
var color = d3.scale.category10();
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
svg.append("circle")
.style("fill", "none")
.style("stroke", "#555")
.attr("r", innerRadius);
svg.append("circle")
.style("fill", "none")
.style("stroke", "#555")
.attr("r", outerRadius);
svg.append("g")
.style("stroke", "#555")
.style("fill", "none")
.attr("class", "corner")
.selectAll("circle")
.data(d3.merge(arcs.map(function(d) {
return [
{angle: d.startAngle + padAngle / 2, radius: outerRadius - cornerRadius, start: +1},
{angle: d.endAngle - padAngle / 2, radius: outerRadius - cornerRadius, start: -1},
{angle: d.endAngle - padAngle / 2 * outerRadius / innerRadius, radius: innerRadius + cornerRadius, start: -1},
{angle: d.startAngle + padAngle / 2 * outerRadius / innerRadius, radius: innerRadius + cornerRadius, start: +1}
];
})))
.enter().append("circle")
.attr("cx", function(d) { return d.start * cornerRadius * Math.cos(d.angle) + Math.sqrt(d.radius * d.radius - cornerRadius * cornerRadius) * Math.sin(d.angle); })
.attr("cy", function(d) { return d.start * cornerRadius * Math.sin(d.angle) - Math.sqrt(d.radius * d.radius - cornerRadius * cornerRadius) * Math.cos(d.angle); })
.attr("r", cornerRadius);
svg.append("g").selectAll("path")
.data(arcs)
.enter().append("path")
.style("fill", function(d, i) { return color(i); })
.style("fill-opacity", .25)
.style("stroke", "#000")
.style("stroke-width", "1.5px")
.attr("d", arc);
</script>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment