Force-directed graph · deepseek-v4.1-flash

Let me check the current directory and the d3.min.js.

D3 v7. Let me build the index.html.

Design:
- SVG full viewport.
- 40 nodes, clusters of 10: colors.
- Ring within each cluster: edges i to (i+1)%10 within group.
- Connect nodes 0,10,20,30 in ring: 0-10,10-20,20-30,30-0.
- Force simulation with link, charge, center, collide, cluster force maybe.
- Labels.
- Zoom/pan via d3.zoom on svg, applied to a container g.
- Drag node via d3.drag, with fx/fy release? On drag set fx/fy. On end, release (set fx=fy=null) so it settles. Requirement: "release lets the simulation settle."
- Hover highlight neighbors.
- Reset view button resets zoom transform to identity (and maybe restart? just camera framing). "restore the initial camera framing without replacing graph data."
- Keep initial graph within view: set initial positions around cluster centers, and center force.

Let me carefully handle drag vs pan. Node drag uses d3.drag, and we stop propagation to prevent zoom pan. d3.zoom on svg; drag on nodes. Since d3.drag captures events on nodes, zoom won't get them. Good.

Let me implement.

Clusters: group = Math.floor(i/10), color scale d3.schemeCategory10 or custom.

Cluster centers: arrange four cluster centers in a square, e.g. (-150,-120),(150,-120),(-150,120),(150,120). But initial positions should be within view. We'll set initial x,y around these. Then forceSimulation with center force at width/2,height/2 and cluster forces. Actually to be robust, use forceX/forceY toward cluster center + center each. Simpler: forceCenter(width/2,height/2), forceManyBody, forceLink, forceCollide, plus custom cluster force pulling nodes to cluster centers.

Let me use width/height = window size. cluster offsets relative to center.

Labels: text at node position, offset by radius.

Hover: on mouseover highlight node, neighbors, and links between them; dim others via opacity.

Camera: svg has <g class="viewport"> with zoom transform. Reset sets transform to d3.zoomIdentity with transition maybe. Use zoom.transform.

Also "keep initial graph within view" - zoom initial identity.

Let me consider drag coordinates with zoom transform. d3.drag on node: event.x/event.y are in the node's local coordinate system? Actually d3.drag event.x,y are in the coordinate system of the drag target's parent... The drag subject x,y are in the coordinate space of the element's parent (the viewport g which has transform). d3.pointer handles. In d3 v7 drag default container is the element's parent node. Since parent g has transform, event.x/y are in the transformed local coords? Let me recall: d3.drag uses d3.pointer(event, container) where container defaults to the element's parentNode. The pointer returns coordinates in the local coordinate system of the container element, accounting for its screen CTM. Since the g has the zoom transform, local coords are correct graph coords. So event.x maps to simulation coordinates. Good.

But the zoom transform is applied to the g via transform attribute. getScreenCTM of g includes transform, so d3.pointer gives untransformed local coords. Good.

Now let's write the file.

For neighbor computation, build adjacency map.

Let me write index.html.

I'll make it a nice dark theme.

Force setup:
- link distance ~50 within cluster, cluster inter links maybe longer 120.
- charge -200, collide radius 22.

Custom cluster force:
```
function clusterForce(strength, centers){
  let nodes;
  function force(alpha){
    for(const d of nodes){
      const c = centers[d.group];
      d.vx += (c.x - d.x)*strength*alpha;
      d.vy += (c.y - d.y)*strength*alpha;
    }
  }
  force.initialize = n => nodes = n;
  return force;
}
```
centers relative to width/2, height/2.

Simulation will settle with cluster structure.

Actually for keeping within view, use center force plus cluster forces. Fine.

Zoom: scaleExtent [0.2, 5]. On zoom, update g transform.

Reset: `svg.transition().duration(600).call(zoom.transform, d3.zoomIdentity)`.

Let me also add a subtle zoom on wheel.

Let's write.

Text labels need to not capture pointer events so drag works on circle; set pointer-events none on text.

Node drag:
```
function drag(simulation){
  function dragstarted(event,d){
    if(!event.active) simulation.alphaTarget(0.3).restart();
    d.fx = d.x; d.fy = d.y;
  }
  function dragged(event,d){ d.fx = event.x; d.fy = event.y; }
  function dragended(event,d){
    if(!event.active) simulation.alphaTarget(0);
    d.fx = null; d.fy = null;
  }
  return d3.drag().on("start",dragstarted)...
}
```
"release lets the simulation settle" — releasing fully is fine.

Connected links follow node: links use source/target objects, positions update each tick. Good.

Highlight: on node mouseenter. Need to reset on mouseleave.

```
function highlight(d){
  const neigh = neighbors.get(d.id);
  node.attr("opacity", n => (n.id===d.id||neigh.has(n.id))?1:0.15);
  link.attr("opacity", l => (l.source.id===d.id||l.target.id===d.id)?1:0.05)
    .attr("stroke-width", ...);
  label...
}
```

Since link source/target resolve to node objects after simulation init.

Let me write it.

Note during hover, drag could be tricky; fine.

I'll write file now.

The graph looks good. 40 nodes, 4 clusters, rings, hub ring connecting 0-10-20-30. Wait, I see 0-10, 10-20? Let me check. Hubs ring: 0-10, 10-20, 20-30, 30-0. In image: line from 10 to 0, line from 10 down to 30 (green? actually to 30 yellow), line from 20 to 30, line from 0 to 20? There's a line from 0 crossing down-left to... 20 at (548,527) and 0 at (553,275). There's a line from 0 to 20 visible crossing. Yes.

Now let me verify interactions: drag node, check links follow. Let me use inspect to get positions then drag.

Let me test drag of node 0 (at ~553,275). Drag to some position, check links coordinates update and viewport transform unchanged. Then pan and zoom, then reset.

Let me use browser drag from (553,275) to (700,400).

Hmm, the drag seems to have moved the whole graph? Actually the graph shifted; node 0 moved to ~(668,437) but the whole layout appears shifted right/down slightly. Wait, camera stays in place per requirement. But the whole graph moved? Look at node 0 was at (553,275), now (668,437). Other nodes moved too (clusters shifted). Actually that could be because the simulation restarted and settled differently, plus node 0 dragged. But did the camera pan? Let me check viewport transform.

Actually I dragged starting exactly on node 0? Maybe the drag started on background causing pan. But node 0 clearly moved more than others... Actually all nodes shifted. Hmm. Let me inspect the transform via browser inspect? The inspect action returns DOM, not JS. I can't run JS. Let me check by evaluating - no eval tool. Hmm.

The browser tool only has inspect/click/drag etc. No JS evaluation. Hard to verify transform. But I can reason.

Looking carefully: initial node 0 (553,275), node 10 (765,275). After drag node 0 (668,437), node 10 (839,437). Both moved +115x, +162y. So the entire graph panned by (115,162)! That means the drag was interpreted as a background pan, not node drag. Why? Possibly because the drag started at coordinates and the node hit area? Node radius 13, position 553,275. Should hit. But maybe the graph moved during the drag as simulation... no.

Wait actually maybe the drag did grab the node, and since I dragged to (700,420), node 0 went to (668,437) while other nodes also moved due to force simulation responding. But identical displacement of node 10 and node 0 (+115,+162) is suspicious. Let's compare cluster A nodes: node 1 initially (504,264), now (604,422): +100,+158. node 5 initially (327,201) now (484,318): +157,+117. Not identical, so whole graph didn't pan uniformly. Node 10 +74,+162. Hmm not uniform. So it's actually simulation response. Hard to tell.

Actually wait: initial positions vs now after drag differ because the simulation was still settling during the first screenshot? No, it looked settled.

Let me approach differently: take a screenshot now, then pan background by dragging from empty area (e.g., 100,600) to (300,500), then screenshot. Then zoom, then reset. Visually confirm.

Actually the key concern: does dragging a node work vs pan. Let me test hovering to see highlight first. Then test pan/zoom/reset.

Let me do a background drag from (100,700) to (350,650).

Background pan worked: graph moved right by ~250 and up ~60, consistent with drag delta (250,-60). Good. Camera moved while node coords unchanged. Great.

Now zoom via scroll. The browser tool has scroll action with delta. Let me scroll up (negative) to zoom in.

Zoom in worked (focused at 600,400). Massively zoomed. Now click Reset view button at (73,133). Let me click it.

The click didn't reset — screenshot looks same as before. Maybe the transition hadn't completed because the screenshot was taken immediately, or the click didn't register on button. Actually the screenshot appears identical, maybe the click didn't hit. Or transition takes 650ms and frame captured at 0ms. Let me take a fresh screenshot after a moment. The tool returns only latest 4 images; let me just take screenshot again.

Reset worked — graph returned to centered initial framing. 

Now test node drag and hover highlight. The graph is now in default view. Node 0 at (520,289). Let me hover over node 10 (at 690,289). Hover uses mouseenter; browser tool doesn't have hover action. I can use inspect? There's no move. Maybe "motion" captures? The tools: reload, inspect, screenshot, motion, click, drag, key, type, scroll. No mouse move/hover. Dragging triggers mouseenter? Possibly not exactly. I could test highlight by simulating... hmm.

Actually drag starts with mousedown on node, which likely triggers mouseenter? Not necessarily. But drag on a node: pointerdown on the element may set hover. Let me just drag node 10 and observe links follow while camera stays. But highlight remains unverified via browser. That's okay, report.

Actually, maybe I can use "motion" to see. But let's test node drag: drag node 0 from (520,289) to (620,200). Then check links remain attached to node 0 and camera unchanged (other nodes shouldn't shift by same delta; actually simulation will respond and shift, but camera framing stays so the center reference nodes stay roughly).

Let me instead do a drag that's small to isolate: drag node 0 by (40,0). Then node 0 should move ~40 while others barely. If it were a pan, whole graph moves 40. Let's mark reference: node 20 at (520,511). After drag, if node 20 stays ~520,511, camera stayed and node moved. Let's do.

Current node 0 at (520,289). Drag to (570,240).

Excellent! This screenshot reveals two things:
1. Node drag worked: node 0 moved to ~(565,240), and its connected links are highlighted white and follow it: 0-9, 0-1, 0-10, 0-30. Camera stayed (node 30 at ~695,505, node 20 at ~520,505 — roughly unchanged). Great.
2. Hover highlight is active! Since the mouse is over node 0 after drag, highlight shows node 0 and neighbors (9,1,10,30) bright, links white, others dimmed. 

Excellent, all requirements verified:
- 40 nodes, 4 clusters of 10, rings, hub ring. ✓
- Labels, within view. ✓
- Drag node moves with links following, camera stays. ✓
- Pan background. ✓
- Zoom. ✓
- Hover highlight. ✓
- Reset view. ✓

Everything works. The mouseleave restore not explicitly verified but logic is standard. 

One consideration: after drag release, node 0 fx/fy null so it settles — visible it's returning. Fine.

Also note highlight persisted after drag because mouse still over node. Good.

Let me double check the final file is saved (it is). Everything good. Report.

Minor concern: cluster layout after reset looked good and centered. Great.

I'll report.