Uniform Random II by mbostock

index.html

<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>

var width = 960,
    height = 500;

var sample = uniformRandomSampler(width, height, 10000),
    samples = [],
    s;

while (s = sample()) samples.push(s);

var voronoi = d3.geom.voronoi()
    .clipExtent([[0, 0], [width, height]]);

var canvas = d3.select("body").append("canvas")
    .attr("width", width)
    .attr("height", height);

var context = canvas.node().getContext("2d");

var image = new Image;
image.src = "starry-night.jpg";
image.onload = start;

function start() {
  context.drawImage(image, 0, 0);
  image = context.getImageData(0, 0, width, height);
  voronoi(samples).forEach(function(cell) {
    var x = Math.floor(cell.point[0]),
        y = Math.floor(cell.point[1]),
        i = (y * width + x) << 2;
    context.fillStyle = d3.rgb(image.data[i + 0], image.data[i + 1], image.data[i + 2]) + "";
    context.beginPath();
    context.moveTo(cell[0][0], cell[0][1]);
    for (var i = 1, n = cell.length; i < n; ++i) context.lineTo(cell[i][0], cell[i][1]);
    context.closePath();
    context.fill();
  });
}

function uniformRandomSampler(width, height, numSamplesMax) {
  var numSamples = 0;
  return function() {
    if (++numSamples > numSamplesMax) return;
    return [Math.random() * width, Math.random() * height];
  };
}

</script>