index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style>
rect{
fill: white;
}
circle {
stroke: #000;
stroke-opacity: .5;
}
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>
var width = 960,
height = 500;
var nodes = d3.range(5).map(function(i) {
return {
type: Math.random() * 5 | 0,
radius: 30,
fixed: true,
type: i,
x: (i + 1) * (width / 6),
y: height / 2
};
});
var color = d3.scale.category10();
var force = d3.layout.force()
.gravity(0)
.charge(0)
.nodes(nodes)
.size([width, height])
.on("tick", ticked);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height)
.on("mousemove", mousemoved);
svg.append("rect")
.attr("width", width)
.attr("height", height);
svg.selectAll("circle")
.data(nodes)
.enter().append("circle")
.attr("r", function(d) { return d.radius - 2; })
.style("fill", function(d) { return color(d.type); });
var p0;
force.start();
function mousemoved() {
var p1 = d3.mouse(this);
p0 = p1;
var node = {
radius: Math.random() * 12 + 4,
type: Math.random() * 5 | 0,
x: p1[0],
y: p1[1],
px: (p0 || (p0 = p1))[0],
py: p0[1]
};
svg.append("circle")
.data([node])
.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; })
.attr("r", function(d) { return d.radius - 2; })
.style("fill", function(d) { return color(d.type); })
.transition()
.delay(3000)
.attr("r", 1e-6)
.each("end", function() { nodes.splice(6, 1); })
.remove();
nodes.push(node);
force.resume();
}
function ticked(e) {
var q = d3.geom.quadtree(nodes),
k = e.alpha * 0.1,
i = 0,
n = nodes.length,
o;
while (++i < n) {
o = nodes[i];
if (o.fixed) continue;
c = nodes[o.type];
o.x += (c.x - o.x) * k;
o.y += (c.y - o.y) * k;
q.visit(collide(o));
}
svg.selectAll("circle")
.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; });
}
function collide(node) {
var r = node.radius + 16,
nx1 = node.x - r,
nx2 = node.x + r,
ny1 = node.y - r,
ny2 = node.y + r;
return function(quad, x1, y1, x2, y2) {
if (quad.point && (quad.point !== node)) {
var x = node.x - quad.point.x,
y = node.y - quad.point.y,
l = Math.sqrt(x * x + y * y),
r = node.radius + quad.point.radius;
if (l < r) {
l = (l - r) / l * .5;
node.px += x * l;
node.py += y * l;
}
}
return x1 > nx2
|| x2 < nx1
|| y1 > ny2
|| y2 < ny1;
};
}
</script>