Force-directed graph · qwen3.8-27b

Let's check the environment and write the file.

Write index.html. Features:
- 40 nodes, clusters of 10 each, color-coded; intra-cluster rings; inter-cluster hub ring 0-10-20-30-0.
- Force simulation, node ID labels, fit graph within view (set zoom transform based on bounding box).
- Node drag: d3.drag on nodes, with simulation reheat.
- Background pan + wheel zoom: d3.zoom on svg, apply to <g>.
- Hover highlight: node + adjacent nodes + connecting links; dim others.
- Reset view button: transition to the initial transform.

Implementation details:

- SVG with a g container. Zoom behavior on svg: transform g. Node drag: on drag, update fx/fy in graph coordinates — need to account for zoom transform: use d3.pointer relative to the g container (d3.drag's subject uses container? d3.drag's default container is the parent element, so use event.x/y as coordinates in container g's coordinate system, which works with the transform). Actually, d3.drag's default container is the parent node of the selected element, so event.x/y are in the container's local coordinate system (i.e., transformed). Good.

- Prevent zoom from firing during node drag: d3.drag's default filter stops mousedown; node drag calls event.stopPropagation, and drag automatically stops propagation (d3.drag stops mousedown propagation). Standard pattern works.

- Highlight: build an adjacency map. On mouseover: compute the set of adjacent nodes; set classes. On mouseout: remove them.

- Reset view: svg.transition().call(zoom.transform, initialTransform).

- Initial framing: run the simulation (either await a few ticks, or compute after settling) — easiest approach: pre-run simulation.tick() many times synchronously (e.g., 300 ticks), then compute bounding box and fit zoom transform. But then the simulation visually "settles" before display — that's fine. Actually, the requirements say dragging causes the graph to respond, and release lets it settle — the simulation is running. Pre-running 200 ticks before rendering makes the initial layout stable within view. Then continue the simulation from there (alpha decays; set alpha(0.3) for a gentle motion? Or leave it as is). To keep it stable while interactive, restart the simulation after pre-ticking with a low alpha — that's fine.

Simpler: after simulation.stop() and manual ticks, render positions, and call simulation.restart() with alpha set to 0.3 or something? Pre-tick with alphaDecay default: after 300 ticks alpha ~ (1-0.0228)^300 ≈ 0.001 — nearly stopped. Then restart with alpha(0.2)? That would cause motion. Requirement: "keep the initial graph within view" — pre-tick then compute the fit is sufficient; leave the simulation running (with near-zero alpha it's stable, and re-heats on drag).

Fit: use node radius, compute bbox from node positions, scale = min(w/bw, h/bh, ~1.2), translate so the center aligns.

Node radius: 10, maybe 13 for hub nodes. Labels below/centered.

Colors: d3.schemeTableau10 or 4 custom colors.

Let's write the file.

One issue: the simulation has been pre-executed with .stop(), but ticked is called manually. After that, `simulation.on("tick", ticked)` is set at the end — no problem. However, the simulation has stopped, and the tick handler is only set later. During dragging, alphaTarget(0.3).restart() works.

Another issue: the drag behavior and zoom on the svg — d3.drag on nodes stops propagation, so zoom won't interfere. Good.

Load it in the browser and test.

Looks good — 40 labeled nodes, 4 color-coded clusters, within view, no console errors. Next, test: node dragging, panning, zooming, reset, hover.

Test dragging node 30 (orange hub at approximately 481,367). Drag to a new position and confirm that the link follows.

Node 30 moved to a new position, its links (to 0, 31, 39) follow, and the camera didn't change. Next, test panning (drag the background) and zoom.

Pan is working (the view shifted 150,100 to the right). Next, test zoom with wheel. The browser tool has a scroll action with delta — can the mouse wheel zoom via d3.zoom's wheel? A scroll event at some x,y.

Zooming in works. Next, test hovering over a node (mouseover) — does the browser tool have a hover? No, it has click and such. Hover can be simulated by dispatching mouseover in JS, but the tool list doesn't have "evaluate". Can I use click? Hover highlight requires mouseover. I could verify with a small check: dispatch mouseover on a node via the DOM... The "inspect" action exists — maybe I can evaluate? It says "inspect DOM/console". Probably just reports the DOM. Let me try hover via a key event? No, impossible.

Alternative: I can check whether the reset works. Hover highlight is code-level verification, and the logic is simple. But let me try: does the browser tool support a "hover" action? Not in the enum. Can I test hover by using a quick JS injection? There's no evaluate tool. Let me skip it; but at least let me verify that the classes exist in the DOM on the node after a programmatic dispatch — can't do that.

Let me test Reset view:

The screenshot may have been taken at the start of the transition (600ms). Let's take another screenshot after a while to check the final state.

Reset restored the initial framing — matches the first screenshot (node 30 returns to near the original area; note that node 30 remains in the area where it was dragged... wait, in the first screenshot node 30 was at (481,367), but now it's at (530,407). The graph data has moved due to the settling from the drag — as expected: reset only restores the camera, and does not restore the graph data (as required: "without replacing the graph data"). The framing has returned to the initial camera. Good.

Next, hover test: the browser tool doesn't have hover. Should I try moving to a node with the "type" action? No. Hover highlight: could be tested indirectly... the tool only supports click/key/type/drag/scroll/screenshot/inspect/motion. Can't easily dispatch mouseover. I'll note it as untested at runtime, but the code is simple. Actually, could I simulate hover by dragging 0px onto the node? A drag on the node would trigger mousedown/mousemove — d3.drag's start sets fx, and the drag handler fires; if I release at the same location, the node stays. Does mousedown trigger mouseover? The pointer is already on the node, and the highlight handler is bound to mouseover, which fires when the pointer moves over an element — if the pointer is already over it, dragging might not fire mouseover. Risky.

Could I try "key" to trigger it? No. I'll accept it as an unverified behavior and report as such.

Done. Final report.