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@mbostock /.block forked from mbostock/.block
Last active Oct 7, 2016

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Delaunay Triangulation
license: gpl-3.0

An interactive demonstration of d3-voronoi, showing the Delaunay triangulation.

<!DOCTYPE html>
<meta charset="utf-8">
<style>
.triangles {
fill: none;
}
.links {
stroke: #000;
}
.sites {
fill: #000;
stroke: #fff;
}
.triangles .primary {
fill: #f00;
}
.links .primary {
stroke: #fff;
}
.sites :first-child {
fill: #fff;
}
</style>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var svg = d3.select("svg").on("touchmove mousemove", moved),
width = +svg.attr("width"),
height = +svg.attr("height");
var sites = d3.range(100)
.map(function(d) { return [Math.random() * width, Math.random() * height]; });
var voronoi = d3.voronoi();
var triangle = svg.append("g")
.attr("class", "triangles")
.selectAll("path")
.data(voronoi.triangles(sites))
.enter().append("path")
.call(redrawTriangle);
var link = svg.append("g")
.attr("class", "links")
.selectAll("line")
.data(voronoi.links(sites))
.enter().append("line")
.call(redrawLink);
var site = svg.append("g")
.attr("class", "sites")
.selectAll("circle")
.data(sites)
.enter().append("circle")
.attr("r", 2.5)
.call(redrawSite);
function moved() {
sites[0] = d3.mouse(this);
redraw();
}
function redraw() {
var diagram = voronoi(sites);
triangle = triangle.data(diagram.triangles()), triangle.exit().remove();
triangle = triangle.enter().append("path").merge(triangle).call(redrawTriangle);
link = link.data(diagram.links()), link.exit().remove();
link = link.enter().append("line").merge(link).call(redrawLink);
site = site.data(sites).call(redrawSite);
}
function redrawTriangle(triangle) {
triangle
.classed("primary", function(d) { return d[0] === sites[0] || d[1] === sites[0] || d[2] === sites[0]; })
.attr("d", function(d) { return "M" + d.join("L") + "Z"; });
}
function redrawLink(link) {
link
.classed("primary", function(d) { return d.source === sites[0] || d.target === sites[0]; })
.attr("x1", function(d) { return d.source[0]; })
.attr("y1", function(d) { return d.source[1]; })
.attr("x2", function(d) { return d.target[0]; })
.attr("y2", function(d) { return d.target[1]; });
}
function redrawSite(site) {
site
.attr("cx", function(d) { return d[0]; })
.attr("cy", function(d) { return d[1]; });
}
</script>
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