8485038 by patricksurry

The Delaunay triangulation, the dual of Voronoi tesselation, creates a planar, triangular mesh for a given set of points. This example updates the Delaunay triangulation in response to mouse interaction! Colors by Cynthia Brewer; algorithm by Steven Fortune; implementation based on work by Nicolas Garcia Belmonte; interaction inspired by Raymond Hill.

index.html

<!DOCTYPE html>
<meta charset="utf-8">
<style>

path {
  fill: yellow;
  stroke: #000;
}

circle {
  fill: #fff;
  stroke: #000;
  pointer-events: none;
}

.PiYG .q0-9{fill:rgb(197,27,125)}
.PiYG .q1-9{fill:rgb(222,119,174)}
.PiYG .q2-9{fill:rgb(241,182,218)}
.PiYG .q3-9{fill:rgb(253,224,239)}
.PiYG .q4-9{fill:rgb(247,247,247)}
.PiYG .q5-9{fill:rgb(230,245,208)}
.PiYG .q6-9{fill:rgb(184,225,134)}
.PiYG .q7-9{fill:rgb(127,188,65)}
.PiYG .q8-9{fill:rgb(77,146,33)}

</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>

var width = 960,
    height = 500;

var vertices = d3.range(100).map(function(d) {
  return [Math.random() * width, Math.random() * height];
});

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
    .attr("class", "PiYG")
    .on("mousemove", function() { vertices[0] = d3.mouse(this); redraw(); });

var path = svg.append("g").selectAll("path");

svg.selectAll("circle")
    .data(vertices.slice(1))
  .enter().append("circle")
    .attr("transform", function(d) { return "translate(" + d + ")"; })
    .attr("r", 2);

redraw();

function redraw() {
  path = path.data(d3.geom.delaunay(vertices).map(function(d) { return "M" + d.join("L") + "Z"; }), String);
  path.exit().remove();
  path.enter().append("path").attr("class", function(d, i) { return "q" + (i % 9) + "-9"; }).attr("d", String);
}

</script>