GraphJS/examples/force-directed.html at main · MarcMouries/GraphJS · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>GraphJS — Force-Directed Layout</title>
<meta name="description" content="Interactive force-directed graph layout. Drag nodes, watch the simulation settle.">
<style>
  :root{
    --bg:#eef1f5; --panel:#f6f8fa; --card:#ffffff; --border:#d0d7de;
    --ink:#1f2328; --muted:#57606a; --accent:#1f6feb; --accent-soft:#ddeafe;
    --mono:ui-monospace,"SF Mono",Menlo,Consolas,monospace;
    --sans:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  }
  *{box-sizing:border-box;margin:0;padding:0}
  html,body{height:100%}
  body{background:var(--bg);color:var(--ink);font-family:var(--sans);overflow:hidden}
  header{position:fixed;inset:0 0 auto 0;height:54px;z-index:5;display:flex;align-items:center;gap:14px;
    padding:0 18px;background:color-mix(in srgb,var(--panel) 88%,transparent);backdrop-filter:blur(10px);
    border-bottom:1px solid var(--border)}
  header .brand{font-weight:800;font-size:15px;letter-spacing:-.01em}
  header .tag{font-family:var(--mono);font-size:10px;letter-spacing:.18em;color:var(--accent);
    background:var(--accent-soft);padding:4px 8px;border-radius:5px;text-transform:uppercase}
  header .spacer{flex:1}
  header nav{display:flex;gap:8px;align-items:center}
  header nav a{font-size:12px;color:var(--muted);text-decoration:none;padding:6px 10px;border-radius:6px;
    border:1px solid transparent}
  header nav a:hover{color:var(--ink);border-color:var(--border);background:var(--card)}
  header nav a[aria-current]{color:var(--accent);border-color:var(--border);background:var(--card);font-weight:600}
  canvas{position:fixed;inset:54px 0 0 0;display:block;cursor:grab}
  canvas.dragging{cursor:grabbing}
  .dock{position:fixed;left:50%;bottom:22px;transform:translateX(-50%);z-index:5;display:flex;gap:8px;
    padding:8px;background:color-mix(in srgb,var(--card) 92%,transparent);backdrop-filter:blur(10px);
    border:1px solid var(--border);border-radius:12px;box-shadow:0 6px 24px rgba(31,35,40,.10)}
  .dock button{font-family:var(--sans);font-size:12.5px;font-weight:600;color:var(--ink);cursor:pointer;
    background:var(--card);border:1px solid var(--border);border-radius:8px;padding:8px 14px;display:flex;align-items:center;gap:7px}
  .dock button:hover{border-color:var(--accent);color:var(--accent)}
  .dock button:active{transform:translateY(1px)}
  .dock .dot{width:8px;height:8px;border-radius:50%;background:var(--accent)}
  .hint{position:fixed;left:50%;bottom:74px;transform:translateX(-50%);z-index:4;font-family:var(--mono);
    font-size:10.5px;letter-spacing:.06em;color:var(--muted);background:color-mix(in srgb,var(--card) 80%,transparent);
    border:1px solid var(--border);padding:5px 12px;border-radius:20px;white-space:nowrap}
  .hint b{color:var(--accent)}
</style>
</head>
<body>
<header>
  <span class="brand">GraphJS</span>
  <span class="tag">Force-Directed</span>
  <span class="spacer"></span>
  <nav>
    <a href="force-directed.html" aria-current="page">Force</a>
    <a href="radial.html">Radial</a>
    <a href="org-chart.html">Org chart</a>
    <a href="https://github.com/MarcMouries/GraphJS">GitHub ↗</a>
  </nav>
</header>

<canvas id="c"></canvas>
<div class="hint"><b>Drag</b> any node · release to let the physics take over</div>
<div class="dock">
  <button id="reheat"><span class="dot"></span>Reheat</button>
  <button id="toggle">Pause</button>
</div>

<script type="module">
import { Graph, ForceDirected } from "./graphjs.esm.js";

const RM = matchMedia && matchMedia("(prefers-reduced-motion: reduce)").matches;

// A small social network with two loosely-connected clusters.
const data = {
  nodes: [
    { id: "ana", name: "Ana" }, { id: "ben", name: "Ben" }, { id: "cara", name: "Cara" },
    { id: "dan", name: "Dan" }, { id: "eve", name: "Eve" }, { id: "finn", name: "Finn" },
    { id: "gina", name: "Gina" }, { id: "hugo", name: "Hugo" }, { id: "ivy", name: "Ivy" },
    { id: "jon", name: "Jon" }, { id: "kim", name: "Kim" }, { id: "leo", name: "Leo" },
  ],
  edges: [
    { source: "ana", target: "ben" }, { source: "ana", target: "cara" }, { source: "ben", target: "cara" },
    { source: "cara", target: "dan" }, { source: "dan", target: "eve" }, { source: "eve", target: "finn" },
    { source: "dan", target: "finn" }, { source: "finn", target: "gina" }, { source: "gina", target: "hugo" },
    { source: "hugo", target: "ivy" }, { source: "ivy", target: "jon" }, { source: "jon", target: "kim" },
    { source: "kim", target: "gina" }, { source: "leo", target: "jon" }, { source: "leo", target: "ana" },
    { source: "eve", target: "kim" },
  ],
};

const c = document.getElementById("c"), ctx = c.getContext("2d");
let W, H, DPR = 1;
const nameOf = (n) => (n.data && n.data.name) || n.id;
const R = 17;

const graph = new Graph();
graph.loadJSON(data);

let layout = new ForceDirected(graph, {
  center: { x: 0, y: 0 },
  linkDistance: 120, repulsion: 6500, gravity: 0.06, collisionRadius: R + 16,
});

// Adjacency, for hover highlighting.
const adj = new Map(data.nodes.map((n) => [n.id, new Set()]));
for (const e of data.edges) { adj.get(e.source).add(e.target); adj.get(e.target).add(e.source); }

function resize() {
  W = innerWidth; H = innerHeight - 54; DPR = Math.min(devicePixelRatio || 1, 2);
  c.width = W * DPR; c.height = H * DPR; c.style.width = W + "px"; c.style.height = H + "px";
  ctx.setTransform(DPR, 0, 0, DPR, 0, 0);
  layout.center = { x: W / 2, y: H / 2 };
  // keep the graph within the visible canvas (leave room for the node radius + label)
  layout.options.bounds = { minX: R, minY: R, maxX: W - R, maxY: H - R - 16 };
}
addEventListener("resize", resize);

let hover = null, dragging = null;
layout.on("tick", draw);
layout.on("end", draw);

function draw() {
  ctx.clearRect(0, 0, W, H);
  const nodes = graph.getNodes();
  const links = graph.linkList || [];
  const lit = hover ? new Set([hover.id, ...adj.get(hover.id)]) : null;

  // Links
  ctx.lineCap = "round";
  for (const l of links) {
    const active = lit && (l.source.id === hover.id || l.target.id === hover.id);
    ctx.beginPath();
    ctx.moveTo(l.source.x, l.source.y); ctx.lineTo(l.target.x, l.target.y);
    ctx.strokeStyle = active ? "#1f6feb" : "#c2ccd6";
    ctx.lineWidth = active ? 2.4 : 1.4;
    ctx.globalAlpha = lit && !active ? 0.4 : 1;
    ctx.stroke();
  }
  ctx.globalAlpha = 1;

  // Nodes
  for (const n of nodes) {
    const dim = lit && !lit.has(n.id);
    ctx.globalAlpha = dim ? 0.35 : 1;
    ctx.beginPath(); ctx.arc(n.x, n.y, R, 0, 7);
    ctx.fillStyle = n === hover ? "#0b57d0" : "#1f6feb"; ctx.fill();
    ctx.lineWidth = 2.5; ctx.strokeStyle = "#ffffff"; ctx.stroke();
    ctx.fillStyle = "#1f2328"; ctx.font = "600 12px " + "-apple-system, Segoe UI, sans-serif";
    ctx.textAlign = "center"; ctx.textBaseline = "top";
    ctx.fillText(nameOf(n), n.x, n.y + R + 4);
  }
  ctx.globalAlpha = 1;
}

function nodeAt(px, py) {
  for (const n of graph.getNodes()) { const dx = px - n.x, dy = py - n.y; if (dx * dx + dy * dy <= (R + 3) ** 2) return n; }
  return null;
}
const pos = (e) => { const r = c.getBoundingClientRect(); return { x: e.clientX - r.left, y: e.clientY - r.top }; };

c.addEventListener("mousemove", (e) => {
  const p = pos(e);
  if (dragging) { layout.pinNode(dragging.id, p.x, p.y); layout.restart(0.35); draw(); return; }
  const h = nodeAt(p.x, p.y);
  if (h !== hover) { hover = h; draw(); }
});
c.addEventListener("mousedown", (e) => {
  const p = pos(e); const n = nodeAt(p.x, p.y);
  if (n) { dragging = n; c.classList.add("dragging"); layout.pinNode(n.id, p.x, p.y); layout.restart(0.5); }
});
addEventListener("mouseup", () => {
  if (dragging) { layout.unpinNode(dragging.id); dragging = null; c.classList.remove("dragging"); layout.restart(0.2); }
});

// Controls
const toggleBtn = document.getElementById("toggle");
let running = true;
document.getElementById("reheat").onclick = () => { layout.restart(1); if (!running) toggleBtn.click(); };
toggleBtn.onclick = () => {
  running = !running;
  if (running) { layout.restart(0.4); toggleBtn.textContent = "Pause"; }
  else { layout.stop(); toggleBtn.textContent = "Play"; }
};

resize();
if (RM) { // settle instantly, no animation
  for (let i = 0; i < 400 && layout.alpha > layout.options.alphaMin; i++) layout.tick();
  running = false; toggleBtn.textContent = "Play"; draw();
} else {
  layout.start();
}
</script>
</body>
</html>