chart = {
const context = DOM.context2d(width, height);
const nodes = data.map(Object.create);
const simulation = d3.forceSimulation(nodes)
.alphaTarget(0.3)
.velocityDecay(0.1)
.force("x", d3.forceX().strength(0.01))
.force("y", d3.forceY().strength(0.01))
.force("collide", d3.forceCollide().radius(d => d.r + 1).iterations(3))
.on("tick", ticked);
d3.select(context.canvas)
.on("touchmove", event => event.preventDefault())
.on("pointermove", pointed);
invalidation.then(() => simulation.stop());
function pointed(event) {
const [x, y] = d3.pointer(event);
for (const d of nodes) {
const xPos = (x - width / 2);
const yPos = (y - width / 2);
const magnitude = Math.sqrt(Math.pow((d.x - xPos), 2) + Math.pow((d.y - yPos), 2));
const minSize = 5;
const r = d.startingSize + 1000 / magnitude;
const maxSize = 50;
d.r = r > maxSize ? maxSize : r;
}
simulation.force("collide").initialize(nodes);
}
function ticked() {
context.clearRect(0, 0, width, height);
context.save();
context.translate(width / 2, height / 2);
for (const d of nodes) {
context.beginPath();
context.moveTo(d.x + d.r, d.y);
context.arc(d.x, d.y, d.r, 0, 2 * Math.PI);
context.fillStyle = color(d.group);
context.fill();
}
context.restore();
}
return context.canvas;
}