mbostock/.block

## .block
license: gpl-3.0

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

circle {
  stroke: #fff;
}

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

var width = 960,
    height = 500,
    padding = 6, // separation between nodes
    maxRadius = 12;

var n = 200, // total number of nodes
    m = 10; // number of distinct clusters

var color = d3.scale.category10()
    .domain(d3.range(m));

var x = d3.scale.ordinal()
    .domain(d3.range(m))
    .rangePoints([0, width], 1);

var nodes = d3.range(n).map(function() {
  var i = Math.floor(Math.random() * m),
      v = (i + 1) / m * -Math.log(Math.random());
  return {
    radius: Math.sqrt(v) * maxRadius,
    color: color(i),
    cx: x(i),
    cy: height / 2
  };
});

var force = d3.layout.force()
    .nodes(nodes)
    .size([width, height])
    .gravity(0)
    .charge(0)
    .on("tick", tick)
    .start();

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

var circle = svg.selectAll("circle")
    .data(nodes)
  .enter().append("circle")
    .attr("r", function(d) { return d.radius; })
    .style("fill", function(d) { return d.color; })
    .call(force.drag);

function tick(e) {
  circle
      .each(gravity(.2 * e.alpha))
      .each(collide(.5))
      .attr("cx", function(d) { return d.x; })
      .attr("cy", function(d) { return d.y; });
}

// Move nodes toward cluster focus.
function gravity(alpha) {
  return function(d) {
    d.y += (d.cy - d.y) * alpha;
    d.x += (d.cx - d.x) * alpha;
  };
}

// Resolve collisions between nodes.
function collide(alpha) {
  var quadtree = d3.geom.quadtree(nodes);
  return function(d) {
    var r = d.radius + maxRadius + padding,
        nx1 = d.x - r,
        nx2 = d.x + r,
        ny1 = d.y - r,
        ny2 = d.y + r;
    quadtree.visit(function(quad, x1, y1, x2, y2) {
      if (quad.point && (quad.point !== d)) {
        var x = d.x - quad.point.x,
            y = d.y - quad.point.y,
            l = Math.sqrt(x * x + y * y),
            r = d.radius + quad.point.radius + (d.color !== quad.point.color) * padding;
        if (l < r) {
          l = (l - r) / l * alpha;
          d.x -= x *= l;
          d.y -= y *= l;
          quad.point.x += x;
          quad.point.y += y;
        }
      }
      return x1 > nx2 || x2 < nx1 || y1 > ny2 || y2 < ny1;
    });
  };
}

</script>

## thumbnail.png

      
    Raw
  

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

	circle {
	stroke: #fff;
	}

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

	var width = 960,
	height = 500,
	padding = 6, // separation between nodes
	maxRadius = 12;

	var n = 200, // total number of nodes
	m = 10; // number of distinct clusters

	var color = d3.scale.category10()
	.domain(d3.range(m));

	var x = d3.scale.ordinal()
	.domain(d3.range(m))
	.rangePoints([0, width], 1);

	var nodes = d3.range(n).map(function() {
	var i = Math.floor(Math.random() * m),
	v = (i + 1) / m * -Math.log(Math.random());
	return {
	radius: Math.sqrt(v) * maxRadius,
	color: color(i),
	cx: x(i),
	cy: height / 2
	};
	});

	var force = d3.layout.force()
	.nodes(nodes)
	.size([width, height])
	.gravity(0)
	.charge(0)
	.on("tick", tick)
	.start();

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

	var circle = svg.selectAll("circle")
	.data(nodes)
	.enter().append("circle")
	.attr("r", function(d) { return d.radius; })
	.style("fill", function(d) { return d.color; })
	.call(force.drag);

	function tick(e) {
	circle
	.each(gravity(.2 * e.alpha))
	.each(collide(.5))
	.attr("cx", function(d) { return d.x; })
	.attr("cy", function(d) { return d.y; });
	}

	// Move nodes toward cluster focus.
	function gravity(alpha) {
	return function(d) {
	d.y += (d.cy - d.y) * alpha;
	d.x += (d.cx - d.x) * alpha;
	};
	}

	// Resolve collisions between nodes.
	function collide(alpha) {
	var quadtree = d3.geom.quadtree(nodes);
	return function(d) {
	var r = d.radius + maxRadius + padding,
	nx1 = d.x - r,
	nx2 = d.x + r,
	ny1 = d.y - r,
	ny2 = d.y + r;
	quadtree.visit(function(quad, x1, y1, x2, y2) {
	if (quad.point && (quad.point !== d)) {
	var x = d.x - quad.point.x,
	y = d.y - quad.point.y,
	l = Math.sqrt(x * x + y * y),
	r = d.radius + quad.point.radius + (d.color !== quad.point.color) * padding;
	if (l < r) {
	l = (l - r) / l * alpha;
	d.x -= x *= l;
	d.y -= y *= l;
	quad.point.x += x;
	quad.point.y += y;
	}
	}
	return x1 > nx2 \|\| x2 < nx1 \|\| y1 > ny2 \|\| y2 < ny1;
	});
	};
	}

	</script>