Force-directed graph · qwen3.8-max-0902

Let me build it.

Key details: 40 nodes, 4 clusters of 10. Rings within clusters, ring connecting 0,10,20,30. Zoom on container g, node drag separate from zoom. Reset view restores initial transform (probably identity or fit-to-view). Hover highlight.

Let me write it.

Check d3 version.

Write index.html.

Design: svg full screen, container g with zoom transform. Simulation with link, charge, center, collision. Initial framing: after simulation settles a bit, compute fit and set initial transform, store as INITIAL_TRANSFORM. Simpler: run simulation with fixed center at width/2,height/2, then compute bounding box and zoom-to-fit once, save transform.

Reset view: transition to that saved transform.

Drag behavior on nodes with event.subject fx/fy; on end release (fx=null) so sim settles. Need to transform coordinates: since zoom applied to container, d3.drag on node circles — the drag coordinates are in the parent's coordinate system automatically? d3.drag uses pointer relative to the container element of the dragged node (event.subject's parent). With zoom on the g, d3.drag by default uses the node's parent as container, so coordinates are in g's local space — correct. Good.

Also need to prevent zoom on node drag: zoom filter default ignores? Zoom's default filter allows mousedown on any element. Since drag is attached to node elements and zoom to svg, drag will call stopPropagation? d3-drag does not stop propagation by default... Actually d3.drag does call event.stopPropagation? In d3-drag, mousedowned calls noevent(event) which does stopPropagation & preventDefault on the source event. Yes, nodrag: d3-drag's mousedowned does `noevent(event)` which stops immediate propagation. Hmm, d3-drag source: function mousedowned(event) { ... noevent(event); ...} Actually it does `if (touchending) ... else { ... nopropagation(event) }`. Yes nopropagation stops propagation so zoom won't pan. Good.

Hover highlight: build neighbor map.

Node labels: text with pointer-events none.

Let me write.

I need to write the index.html file for d3 v7.

Note: node text uses fill dark on colored circle — fine. Also .node.hi circle stroke white; text color dark ok.

Test in browser.

The graph renders correctly: 4 clusters, rings, bridge ring (dashed yellow). The zoom indicator shows 1.00, but the initial fit transform should have been applied after 1.4 seconds — was the screenshot taken before that? The zoom displays 1.00. The fit transform's k might be around 1.0. Actually, the graph fits nicely within the view. Let me check the zoom level after stabilization. The status shows zoom: 1.00 — the fit transform's scale may have been clamped to min(2, 0.95*min(W/bw,H/bh)). bw is probably around 1000, W=1200 → k≈1.14? Hmm, but it shows 1.00. Maybe the screenshot was taken before the 1400ms timeout. The DOM output was captured at frame 1, +0ms. The image might be from after that. Let me take another screenshot now and check the zoom level and interactions.

Tests: hover over a node, drag a node, pan, zoom, reset.

Problem: the clusters have collapsed into dense clumps — the intra-cluster ring links are barely visible (nodes overlap). The ring structure within each cluster has collapsed. Why? The "cluster" custom force pulls nodes toward the cluster center with strength 0.06 per tick, which is strong compared to the link distance of 46 and collide radius of 15. Also, the charge of -220 might be weak compared to the cluster attraction. The rings have collapsed into clumps, and the ring links are hidden behind the nodes.

The first screenshot (right after load) showed clean rings. After stabilization, the cluster force crushed them. Fix: reduce the cluster force strength (e.g., 0.015), increase collide radius (e.g., 16), strengthen the link distance/strength of the intra-cluster rings, and possibly increase charge to -300. Also, the rings should be visible: link distance 46, collide 15 → node radius 11, so with collide 15 the nodes shouldn't overlap much, but... in the screenshot they're overlapping. Collide radius 15 vs node radius 11: diameter 22 > 30? No wait: collide 15 means the minimum center-to-center distance is 30. In the screenshot the nodes look almost touching: at zoom 1, diameter about 22px, spacing about 20px. Hmm, they're overlapping. Maybe the collide force is weak (default iterations 1). Increase iterations to 2-3.

Better approach: drop the custom cluster force entirely, and instead use forceX/forceY per node toward the cluster anchor with a small strength (0.05?). Actually, d3.forceX with per-node strength. The collapse suggests the cluster force's k=0.06 velocity addition is too strong. Use strength 0.02, and increase the link distance within the ring to 55, charge to -260, collide to 16 with iterations 2.

Also, the initial framing: zoom shows 1.00 — did the fit transform get applied? The graph now appears smaller/centered. fitTransform computes k = min(2, 0.95*min(W/bw, H/bh)). With the collapsed layout bw~500 → k = min(2, 0.95*min(1200/500, 800/400)) = min(2, 0.95*2)=1.9? But zoom shows 1.00. Hmm, maybe the screenshot was taken before the 1400ms timeout? The browser's "Frame 1, +0ms" suggests the screenshot timing is at page load? The motion/screenshot tool seems to capture at some point in time. The first screenshot showed a spread-out layout (mid-simulation), and this one shows the settled clumps. So time has passed. But zoom is still 1.00 → maybe the fit transform's k was exactly... bw: x from ~330 to ~860 = 530+140 pad = 670; bh: y from ~130 to ~660 = 530+140=670. k = 0.95*min(1200/670, 800/670)=0.95*1.194=1.13. Not 1.00. So INITIAL wasn't applied? The zoom level display is only updated in the zoom event handler; svg.call(zoom.transform, INITIAL) triggers the zoom event → display updates. Showing 1.00 means either the transform is identity, or the handler wasn't triggered.

Wait — the second screenshot's layout is centered and smaller than the first. The first screenshot showed a spread-out layout with rings at the edges. The second shows compact clumps. That's simulation stabilization, not zoom.

Hmm, but zoom: 1.00. Maybe the setTimeout at 1400ms ran before stabilization and computed a fit on the mid-layout... still k shouldn't be 1.00.

Maybe... the `svg.call(zoom.transform, INITIAL)` inside setTimeout: no problem. But the display: document.getElementById("zoomlevel") updates on the zoom event. Shows "1.00". So either the transform is identity, or the event didn't fire.

Ah! I see the bug: `svg.call(zoom)` then `svg.call(zoom.transform, INITIAL)` — this should fire. Hmm, but maybe an exception was thrown inside fitTransform? Math.min.apply(null, xs) is fine. d3.zoomIdentity.translate... fine.

Wait, maybe the screenshot was taken before 1400ms? The tool's "Frame 1, +0ms" suggests the screenshot is taken immediately at capture time, but the page had already been loaded for a while from the previous call? The first reload showed a mid-simulation layout (rings still spread out from initial positions). The second screenshot (a separate call, later) shows the settled clumps. So more than 1400ms has elapsed. Therefore INITIAL should have been applied... unless the zoom handler's display update failed? It's inside the zoom handler, and it also sets root's transform. If the transform had been applied, the layout would appear scaled by k≈1.13 and translated — hard to tell visually. But the display shows 1.00.

Hmm, wait: maybe the zoom event fired with transform k=1.13 and the display updated to "1.13", but then... no, the display shows 1.00.

Let me check in the browser: inspect the DOM's status text and root's transform attribute. Use browser inspect, or run a script? The browser tool has "inspect" — inspect the DOM. Let me query the transform attribute.

Actually, maybe the issue is: `svg.call(zoom.transform, INITIAL)` inside setTimeout — but `zoom.transform` requires a selection; svg.call(zoom.transform, t) is correct.

Or an exception: `INITIAL = fitTransform();` — fitTransform uses nodes' x/y, which is fine.

Hmm, but wait: maybe the screenshot was taken at a point when the page was freshly reloaded for each browser call? "Frame 1, +0ms" on both. If each browser action reloads the page... the first reload showed a mid-simulation state (about 1s in?). The screenshot call shows the settled clumps — that requires several seconds. Unless the screenshot tool waits. Confusing.

Let me inspect the DOM directly to check the current transform and zoom text.

Issues:
1. Clusters collapse into clumps — the intra-cluster rings aren't visible. Fix the forces: weaken the custom cluster attraction, strengthen collide, and increase the ring link distance.
2. Zoom display shows 1.00 — it seems the initial fit transform was never applied even once. Why? Perhaps because the browser tool reloads the page on each action, and screenshots are taken quickly (around the 0ms frame?). But the layout looks like it's in a converged state... Actually, if the page reloads on each action and the screenshot is taken at "Frame 1, +0ms", then maybe the tool is fast-forwarding the simulation? No — d3's simulation runs in real time via a timer. Hmm, but the layout in screenshot 2 is converged (alpha decayed). That takes about 300 ticks ≈ 5 seconds in real time. Unless the tool is waiting.

Maybe the tool's page runs with timers fast-forwarded? Unclear. The zoom display "1.00": if the 1400ms setTimeout had fired, the display should show the fit's k. Unless k rounds to 1.00? Let me compute: converged bounding box: x is about 330 to about 860 → bw+2*pad = 530+140=670; y is about 130 to about 660 → 670. k=0.95*min(1200/670, 800/670)=0.95*1.194=1.13 → display should be "1.13". So it wasn't applied.

Or the transform was applied but then... the display is only updated on zoom events; zoom.transform triggers the event. Hmm.

Wait — maybe an exception was thrown before setTimeout was scheduled? No, the simulation is running (layout changed between screenshots).

Maybe `svg.call(zoom.transform, INITIAL)` throws an exception? zoom.transform on a selection: `selection.call(zoom.transform, t)` is valid.

Hmm, but actually: the screenshot might be from a new page load where time was compressed: "Frame 1, +0ms" — maybe the harness loads the page, waits for network idle + a bit, then screenshots. The converged layout suggests several seconds elapsed. So the setTimeout(1400) should have fired...

Unless the harness's iframe sandbox blocks setTimeout? Unlikely.

Let me test directly: evaluate in the page? The browser tool doesn't have an eval action. Actions: reload, inspect, screenshot, motion, click, drag, key, type, scroll. No JS eval. Hmm. inspect returns DOM/console. The console only shows iframe sandbox warnings.

Alternative: verify with a headless check? I can run node? d3.min.js is UMD; can I simulate in node? Not needed.

Let me think about the zoom display again: the `zoom` handler sets the text on every zoom event. If INITIAL was applied via zoom.transform, the event fires → display updates. So display 1.00 = identity transform = either not applied, or applied with k=1 and translate 0? fitTransform: translate(W/2,H/2).scale(k).translate(-cx,-cy). If k≈1.13 and cx,cy≈(600,400), then the resulting transform ≈ translate(600-1.13*600, 400-1.13*400) scale 1.13 = translate(-78,-52) scale(1.13). Display should be "1.13".

So it wasn't applied. Why? Maybe an exception inside fitTransform: `Math.min.apply(null, xs)` is fine... `d3.zoomIdentity.translate(...)` is also fine.

Ah, wait. Got it: inside setTimeout I call `svg.call(zoom.transform, INITIAL)`. But `zoom` was defined with `.on("start"...)` etc. That's fine.

Hmm, maybe the issue is: the harness reloads the page on each browser action, and the screenshot is taken right after load (0ms) — but then the layout should be the initial spread-out one, not converged. Unless the harness fast-forwards: some harnesses use fake timers or CDP to accelerate time? "Frame 1, +0ms" might refer to the motion frame capture.

Or maybe the page has been open since the first reload and timers have run; each action just captures the current state. Then the 1400ms timeout fired long ago. But the display is 1.00...

Hmm, let me look at the zoom handler again:

.on("zoom", function (event) { root.attr("transform", event.transform); ... })

And resetView uses svg.transition().call(zoom.transform, t).

The initial apply: svg.call(zoom.transform, INITIAL) — direct, no transition. Should work.

Unless an exception was thrown inside the setTimeout callback before that: INITIAL = fitTransform(); if fitTransform throws, INITIAL stays null and the 4000ms fallback also calls fitTransform → throws again → uncaught, console error should show. Console only shows sandbox warnings. So no exception.

Wait, maybe the console output is truncated to warnings only? It shows the console array with one warning. An uncaught error should appear.

Hmm, maybe... the harness's page is inside a sandboxed iframe where `window.innerWidth` is the iframe size (1200x800?). Fine.

Let me compute the expected k from screenshot 2 more carefully: cluster clumps: leftmost node x≈345, rightmost ≈850. Top y≈140, bottom ≈660. pad 70 → x0=275, x1=920 → bw=645; y0=70, y1=730 → bh=660. k=0.95*min(1200/645=1.86, 800/660=1.21)=0.95*1.21=1.15. Display should be 1.15.

So really not applied. Why?

Ah. Got it now! `setTimeout` callback: `svg.call(zoom.transform, INITIAL);` — but `zoom.transform` — in d3 v7, `zoom.transform(selection, transform)` is called as selection.call(zoom.transform, transform). Yes, that's what I did.

Hmm wait, but maybe the issue is that the harness reloads the page on each action, and screenshots are taken about 0ms after load, but the d3 simulation... no, convergence needs time.

Unless the harness pre-runs the page for a fixed duration (e.g., 5 seconds) before capture, but the displayed DOM text is from the capture moment... then the display should show the applied k.

Let me try another approach: test the timing hypothesis using the motion action (frames over time). Or simpler: make the initial framing synchronous and deterministic: instead of setTimeout, pre-run the simulation ticks manually (simulation.tick() about 300 times) before the first render, then compute INITIAL immediately and apply. This removes the timing dependency and also gives a stable, converged layout at load. Then the display updates immediately.

Also fix the clumping: tune forces so rings remain visible:
- Remove the custom cluster force or make it much weaker (0.02).
- Link distance: intra-cluster 40, strength 1; bridge distance 260, strength 0.2.
- Charge -300.
- Collide radius 16, iterations 2.
- Use forceX/forceY toward cluster anchors with strength 0.08? That's what caused the clumping. The clumping happened because the cluster attraction overwhelmed the ring link repulsion? Actually, the ring links with distance 46 and strength 0.9 should keep spacing at 46. But collide 15 allows overlap down to 30... in the screenshot spacing is about 20-25px, less than 30. Hmm, collide's default strength is 0.7, iterations 1 — weak.

The real cause of clumping: the custom cluster force adds velocity toward the center each tick with k=0.06 — that's a strong constant attraction; the link force tries to maintain distance 46 but the charge -220 is moderate. Equilibrium: 10 nodes all attracted to the center; the ring links only connect neighbors, so the whole ring can shrink: the links maintain distance 46 between neighbors... but in the screenshot neighbor spacing is about 25px, meaning the link force lost. With strength 0.9 and distance 46, it should push apart. Unless the cluster force's per-tick velocity addition of 0.06*dist is huge: at dist 100 → dv=6/tick, whereas the link force's correction is on the order of (46-25)/46*bias*strength ≈ small. Yes, the cluster force dominates.

Fix: k=0.01, or use d3.forceX/forceY with strength 0.05 toward the anchor? forceX strength 0.05 also adds velocity proportional to distance each tick: dv = (target-x)*0.05 — same magnitude as my 0.05. Hmm, my k was 0.06. Typical cluster examples use strength 0.1?? No, typical is: strength(0.1) is for loose grouping with charge -300 and link distance... but those examples don't need ring spacing.

Better: rely on link+charge only, and give initial positions per cluster; add a weak forceX/forceY with strength 0.03 to keep clusters apart. And pre-run ticks.

Parameters:
- charge -400 (spread within ring)
- link distance: ring 50, strength 0.8; bridge 300, strength 0.15
- forceX/forceY toward cluster anchor strength 0.04
- collide 18, iterations 2
- center force on overall.

Pre-run: simulation.stop(); for (i<300) simulation.tick(); then render once and set positions; then keep the simulation running at low alpha for drag interactivity (alpha 0.0? restart with alphaTarget 0 on drag). After pre-run, call simulation.alpha(0) — but drag needs restart; drag handler restarts with alphaTarget(0.3). Fine: after pre-run, simulation.alpha(0.0).stop()? Then the tick handler won't run until drag restarts. But on drag restart, positions update via the tick event. Good. Also keep a slight alpha 0.05 for organic settling? Simpler: after pre-run, simulation.alpha(0).restart()? alpha 0 means it stops immediately (alphaMin 0.001). Use simulation.alpha(0). Then on drag: alphaTarget(0.3).restart() works.

But then the "simulation converges on release" behavior: on drag end alphaTarget(0) → alpha decays → converges. Good.

Initial framing: compute fitTransform after pre-run, apply immediately via zoom.transform (no transition). INITIAL is set synchronously.

Also, on resize recenter: fine.

Also, the hover raise() on the node group: raises the g.node element — ok.

One more: the node text fill is dark (#06101f) on colored circles — readable.

Bridge link distance 300 with strength 0.15; plus forceX anchors at radius R*0.85 keep clusters in a diamond.

Let me also reduce pad to 60 and cap k at 1.6? k = min(1.5, ...). If the layout is about 900x700, k≈0.95*min(1.33,1.14)=1.08. Fine.

Rewrite the relevant script section.

Also, the `INITIAL` variable is declared after the zoom setup, but before its usage site — order: `var INITIAL = null;` is declared after svg.call(zoom), before fitTransform. The new code uses INITIAL after the fitTransform definition — no problem.

But wait: the pre-run loop calls simulation.tick() — the tick event handler isn't registered yet? I registered simulation.on("tick", ...) before that (yes, the handler is registered right after the node/link selection, before the zoom section). The pre-run loop calls tick() directly (the event isn't fired by manual .tick()? Actually, does simulation.tick() fire the "tick" event? In d3-force, simulation.tick() advances the simulation and... dispatches the tick event? Docs: simulation.tick([iterations]) — "Advances the simulation by the specified number of iterations... does not dispatch events"? Let me recall: in d3-force v7, tick() manually advances and dispatches? Source: simulation.tick = function(iterations) { ... step(); ... return simulation; } and step dispatches the "tick" event? Internal step(): `event.call("tick", simulation)`? Hmm. In d3-force source, `step()` updates alpha and calls forces, then `event.call("tick", simulation)`. And the timer calls step. tick() also calls step. I think tick dispatches the tick event. Either way, just to be safe, I added an explicit simulation.on("tick")() call.

Next, drag: on start alphaTarget(0.3).restart() — works even from alpha 0.

Also, the resize handler restarts with alpha 0.25 — no problem.

One more thing: after the pre-run, since alpha=0 and it's not running, the simulation converges; drag reheats it. Good.

Reload and take a screenshot.

The ring is now displayed, and the initial fit has been applied (zoom 0.56). But at zoom 0.56 the nodes are too small — the layout's bounding box is large (bridge distance R*1.5 ≈ 0.32*min(W,H)*1.5 = 384? R = min(1200,800)*0.32=256; bridge distance 384; anchor radius R*0.95=243... the spread of the layout is probably 1400x1200 → k=0.56). The nodes look small because the zoom scales them down. Better approach: make the overall layout more compact so that k ≈ 1: reduce R (0.26), bridge distance R*1.2, anchor radius R*0.9, ring link distance 46. Or set a lower bound on k... fit should fill the view. The problem is that the graph's aspect ratio is too large relative to the viewport. bw/bh ~ 1400/1200; viewport 1200x800 → k=min(1200/1540, 800/1340)*0.95 ≈ 0.56. To get k≈1, the layout needs to fit within ~1100x700. So shrink: R = min(W,H)*0.24 = 192; anchor radius R*0.95=182; ring diameter ~ 10 nodes * 46/π ≈ 146 → cluster radius ~73. Overall spread ≈ 2*(182+73)=510 plus margin → ~600x600. k = 0.95*min(1200/740, 800/740)=0.95*1.08=1.03.

Also, at k=1 the node radius of 11 is fine.

Settings: R = Math.min(W,H)*0.26; anchor 0.95R; bridge distance R*1.3; ring distance 48; charge -320.

Also, node label font 10px is fine.

Update the code: R definition and distances.

Also, the initial position uses R/2.2 for the ring offset — no problem there. Reload and check.

Still zoom 0.62 — layout extent is about (x: 270→930 = 660+pad... wait, k=0.62 means bw ≈ 1200/0.65 ≈ 1850? Hmm, no: k = 0.95*min(W/bw, H/bh). If k=0.62 → min ratio = 0.65 → bh ≈ 800/0.65 = 1230. Indeed, the graph spans y from 60 to 740 = 680 + 140 pad = 820 → 800/820=0.97... doesn't match. Hmm, k=0.62 → H/bh=0.65 → bh=1230? But the visible range is about 680. Unless the transform includes scale 0.62: visible extent = bh*0.62 = 680 → bh = 1097; +pad 140 → bounding box 1097? y range in graph coords = (740-60)/0.62 = 1097. OK, consistent.

So in graph space the layout is about 1100 tall. Cluster anchor radius R*0.95 = 0.26*800*0.95 = 197.6 → vertical anchors at ±197 from center; cluster ring radius ~ (10*48)/(2π) ≈ 76; plus charge spread. Vertical extent ≈ 2*(197+76+node) ≈ 560? But measured is 1097. Something's stretching: bridge link distance R*1.35=275 vs anchor spacing: adjacent anchors (top and right) distance = sqrt(2)*197=279 — consistent. Hmm, vertical extent top cluster center is center-197, top of ring is -197-76=-273; bottom is +273 → 546. But measured 1097?? Screenshot: top node y≈60 (screen), bottom ≈740. Screen = transform(graph). k=0.62, translate? Center is probably (600,400). Graph y range = (740-60)/0.62 = 1097. Contradiction → cluster positions are more spread than anchor radius: forceX strength 0.045 is weak against charge -320 pushing clusters apart? Charge acts between all nodes; inter-cluster repulsion pushes clusters outward beyond anchors. Plus bridge link strength 0.15 is weak.

Options: increase anchor strength to 0.12, reduce charge to -200, or simply accept k and scale node radius inversely? Simpler: after pre-run, fit computes k; instead of fighting physics, we can scale the layout: not needed — k=0.62 makes nodes small (radius 11*0.62≈7px). Labels are tiny.

Better approach: strengthen confinement: forceX/Y strength 0.15, charge -250, bridge distance R*1.2, strength 0.3. Then extent ≈ 2*(197+80)=554+pad*2=694 → k=0.95*min(1200/~800?, 800/694=1.15) → capped by width? x extent similarly ~700 → k≈1.09 → capped at min(2,...) no problem, ~1.09. Node radius 11 → good.

Also intra-cluster ring distance 48, charge -250 is fine.

Let's adjust: anchor strength 0.12; charge -260; bridge distance R*1.25 strength 0.25.

Also ring shape: with strong anchor pull, the ring may get crushed toward the anchor? Strength 0.12 * distance-from-anchor (~76) = dv 9/tick?? That's strong: forceX adds (target - x)*strength to vx each tick: 76*0.12 = 9.1 — too strong, will crush the ring like before (that clumping was 0.06 * ~100 = 6). Hmm, but the previous clumping was with link distance 46 strength 0.9 and charge -220... and it still clumped. So anchor strength must stay small relative to link force. Link force correction per tick: bias*strength*(dist-48)/dist * ... roughly 0.5*0.8*( -20/48 )? Small ~0.17 velocity? Hmm, d3's link force applies position correction scaled by strength*bias*(l.dist - distance)/l.dist to each endpoint's velocity — for a 20px deficit: 0.4*... let me not overthink.

Alternative robust approach: ditch the anchor force entirely; instead fix the 4 anchor nodes? No — simpler: use the bridge ring with appropriate distance/strength to maintain the diamond, and rely on initial positions + charge. Without anchor force, clusters drift but the bridge links (distance ~280, strength 0.3) hold the diamond. Charge repulsion between clusters counteracts. Equilibrium extent is probably larger than anchors but bounded by bridges.

Previous run (first version) had cluster force 0.06 and clumped. Second version (0.045 anchor + weak bridge) spread to ~1100. Middle ground: anchor strength 0.08, bridge strength 0.3 distance R*1.2, charge -260, ring distance 46 strength 1.0, collide 16.

Estimate: anchor pull on ring node at 76 from anchor: 6/tick?? 0.08*76=6 — still large vs link. Hmm, but in version 2 with 0.045 the ring didn't clump (ring looked good!). Because charge -320 + collide maintain spacing. Clumping in v1 was due to 0.06 plus weak collide(15, iter1) and charge -220... v2 kept ring shape with 0.045. So raise slightly to 0.07 and strengthen collide iterations 3, charge -300: ring survives, clusters pulled tighter to anchors → extent ~ 2*(197+90)=574 → +pad → k≈0.95*800/714=1.06.

Let's try: anchor strength 0.07; charge -300; collide 16 iterations 3; bridge distance R*1.25 strength 0.25; ring distance 46 strength 1.

If k still ~0.7, alternative: cap fit k at [0.8, 1.4] and allow slight cropping? No — "keep initial graph in view" is required; cropping is bad. Or scale node visual radius by 1/k? Ugly.

Actually simplest and most reliable: after pre-run, rescale node coordinates to fit target box! I.e., compute bounding box, linearly map positions into a box of (W-160)x(H-160) centered. Then fitTransform gives k≈~0.95*min(...)= ~1.0 by construction (since bbox maps exactly to target box, k = 0.95*min(W/(W-160+2pad?)...). Hmm, pad is added in fit: bw = (W-160)+140 = W-20 → k=0.95*1200/1180≈0.97.

But rescaling distorts link distances — visually fine (it's just initial layout; simulation is idle at alpha 0 so distances stay as scaled until drag reheats... on reheat forces will pull back to natural distances — acceptable, graph responds).

Hmm, but rescaling uniformly (same factor x and y) preserves shape: factor = min((W-160)/bw, (H-160)/bh). Then fit k ≈ 0.95/min... let me compute: after uniform scale s, bbox = bw*s, bh*s ≤ target. fit k = 0.95*min(W/(bw*s+140), H/(bh*s+140)) ≈ 0.95*W/(W-160+140)=0.97 (if width-constrained). Good, k≈0.97, nodes ~11px.

But if we rescale positions, on reheat (drag) forces restore natural scale — graph may expand again beyond view? Charge -300 natural extent was 1100 tall vs post-scale ~660: on reheat it'd re-expand ~1.6x → might exceed view. Hmm. But user can reset view (refit? no — reset restores INITIAL camera, not refit). Spec: reset restores initial camera framing. If graph re-expands after drag, it may go out of view. Mitigation: keep forces consistent with scaled layout: also scale force distances? Overkill.

Alternative cleaner: choose force parameters so natural extent ≈ viewport. Iterate params once more: anchor 0.07 etc. Let's just try and measure k from readout. Each iteration is cheap.

Also, make fitTransform more robust: clamp k to the [0.7, 1.25] range? If the natural extent is still large, k will be small. As a fallback, we could also scale the node coordinates to fit. First, let's check the result.

Improved (k=0.71), but the diamond is still too tall vertically: the top/bottom clusters extend beyond the anchors. The vertical spread is dominated by the ring diameter of the top/bottom clusters plus the anchor radius. k=0.71 → graph-space height ≈ (750-65)/0.71 ≈ 965. Target ≤ ~760 (k≈0.95).

Deterministic fix: after pre-run, uniformly rescale coordinates to fit the target box, and scale the force distances to match too? If we rescale positions but the forces retain natural distances, reheating will re-expand. To keep consistency, scale the link distances and charge strength too? Charge scales with distance squared... complicated.

Alternative: reduce the vertical footprint by placing anchors in a wider diamond: use elliptical anchors: x radius = W*0.30, y radius = H*0.26? The viewport is landscape (1200x800): give more room horizontally: anchors at (±0.32W, 0) and (0, ±0.30H)? Then vertical spread = 2*(0.30H + ring radius ~90) = 480+180=660 → fits in 800 with padding. Horizontal = 2*(384+90)=948 < 1200. k = 0.95*min(1200/(948+140)=1.10, 800/(660+140)=1.0) = 0.95.

So change anchorsXY: place clusters at left/right/top/bottom with different radii: ax = W*0.30, ay = H*0.30. Angles: top (0,-ay), right (ax,0), bottom (0,ay), left (-ax,0).

Ring radius: 10 nodes, distance 46 → circumference 460 → radius ≈ 73; plus charge bulge ~ +20 → ~90. Vertical: 2*(240+90)=660 ✓. Horizontal: 2*(360+90)=900 ✓.

Bridge distance: adjacent anchor distance = sqrt(ax²+ay²)= sqrt(360²+240²)=432; set bridge distance to that value ~ or leave as R*1.25=260? The bridge link pulls anchors closer than the anchor force wants; anchor strength 0.07 vs bridge strength 0.25 — the bridge might win and shrink the diamond. Set bridge strength to 0.1, distance = sqrt(ax²+ay²) ≈ 432 → compute dynamically: bridgeDist = Math.hypot(ax, ay).

Update initial positions similarly (elliptical).

R is currently used for initial ring offset and anchors; replace with ax/ay.

Edits:
- anchorsXY: use elliptical positions.
- Initial position loop: center + elliptical anchor + ring offset radius ~70.
- Bridge distance: Math.hypot(ax,ay)*1.0, strength 0.1.

Code changes:

var AX = W * 0.30, AY = H * 0.30;
var anchorsXY = [{x:W/2, y:H/2-AY},{x:W/2+AX,y:H/2},{x:W/2,y:H/2+AY},{x:W/2-AX,y:H/2}];

Initial values: n.x = anchorsXY[c].x + 70*cos(ca), etc.

Bridge distance: Math.hypot(AX, AY).

Also, the resize handler references R? No, it doesn't. Check the remaining references to R: the initial loop has been deleted; anchorsXY has also been deleted; bridge distance uses AX/AY. Any other uses of R? grep.

There are no remaining references to R. Please reload.

The shape is good now, but zoom is still 0.71. The graph-space extent must still be large: on-screen y is 65→735 = 670 → graph height = 670/0.71 ≈ 944?? Hmm, but the anchors are AY=232 → top anchor y=400-232=168, ring top edge ~168-90=78; bottom edge ~722; height ~644 + pad 140 = 784 → k=0.95*800/784=0.97. But the display shows 0.71. So the actual extent is larger: on-screen top edge 65 → graph y = (65-ty)/k... can't guess directly.

Wait: maybe the fit is constrained by width: on-screen x 175→1020 = 845 → graph width = 845/0.71 = 1190 + pad = 1330 → k=0.95*1200/1330=0.86, not 0.71. Hmm.

Let me measure directly: k=0.71. Screen bbox: x:[175,1020], y:[65,735]. Graph bbox = screen/k: width 845/0.71=1190, height 670/0.71=944. Adding pad*2=140: bw=1330, bh=1084. k check: 0.95*min(1200/1330=0.90, 800/1084=0.74)=0.70 ✓. So the graph-space height is ~944 — much larger than my estimate of 644. Why? The clusters are positioned further out than the anchors: the top cluster center is at screen y≈140 → graph y=(140-?)... transform: translate + scale; center maps to center (600,400)? The graph center (W/2,H/2)=(600,400) maps to screen (600,400) only if the fit centers the bbox center at the viewport center — the bbox center ≈ graph center, roughly. Top cluster center screen (610,140) → graph y = 400 + (140-400)/0.71 = 400-366 = 34?? So the top cluster center is at graph y≈34, i.e. 366 above center — much further than AY=232. So the clusters are being pushed outward beyond the anchors: charge repulsion between clusters + weak anchor (0.07) vs charge -300 across 40 nodes.

Increase anchor strength to 0.12? Risk of ring collapse — but the ring is currently maintained with strength 1 links and collide iter 3; v1's collapse was at 0.06 with weak collide/links. Hmm, v1: link strength 0.9 distance 46, collide 15 iter1, charge -220, cluster k 0.06 → collapse. Now: link strength 1, collide 16 iter3, charge -300. At anchor 0.12, pull on a node 90 from anchor = 10.8/tick — likely to crush the ring again.

Different approach: normalize after pre-run: uniformly rescale positions around the center so bbox fits the target, then also adjust? Reheat-expansion concern: after rescale s≈0.7, natural forces will re-expand on reheat. But is reheat expansion actually a problem? During drag alphaTarget 0.3 — forces act; graph drifts back toward natural extent (~1.4x scaled). Might push outer nodes out of view at k≈0.95. Hmm, but user can reset view... reset restores camera, graph still large. Not great.

Cleanest: make the natural equilibrium match the viewport. Dominant outward push: many-body charge between clusters. Reduce charge to -150 and increase collide to maintain intra-ring spacing (collide ensures ≥32px spacing; ring distance 46 maintained by links). Charge -150 still gives some spread within ring. And anchor strength 0.08.

Estimate: inter-cluster repulsion halves → clusters sit closer to anchors.

Or add forceRadial? Hmm.

Or: keep physics as-is and set fit pad smaller and allow k up to... k is what it is; the problem is nodes appear small (r=11*0.71≈8px, labels 10px*0.71≈7px — barely readable in screenshot). Actually in the screenshot the labels are readable. Honestly k=0.71 isn't terrible. But "keep the initial graph in view" is satisfied. Bigger nodes would look better.

Compromise: scale node visual size by 1/k? No.

Try charge -160, anchor 0.09, collide 16 iter 3, ring distance 44. If k lands ≥0.85, good.

Also reduce pad to 50.

distanceMax(240) limits inter-cluster repulsion (inter-cluster distances are mostly over 240). Good. Reload.

Currently zoom 1.04, the ring is clearly visible, labels are readable, and the entire graph is within the view.

Next, test interactions:
1. Hover on a node → highlight.
2. Drag a node → links follow, camera stays still.
3. Pan the background.
4. Wheel zoom.
5. View reset → returns to initial framing (zoom 1.04, same translate).

Hover test: move to node 0 at (692,157).

Hover works: node 0 is highlighted with a white ring, adjacent nodes 9, 1, 30, 10 are highlighted, connecting links are bright, everything else is dimmed.

Next, move away to test hover release, then drag node 0: drag from (692,157) to (600,300). Verify that links follow and the camera doesn't change (zoom display stays at 1.04, transform is the same). Then pan: drag the background from (600,600) to (750,500); zoom display stays at 1.04 but transform changes. Wheel zoom at center: zoom display changes. Then reset: returns to the original transform (zoom 1.04 and same framing as initial screenshot).

To compare camera, I can record the transform of root g via inspect? The DOM dump doesn't show attributes. The zoom display gives k. For pan, k stays the same but translate changes — visually confirmable in the screenshot.

First, mouseleave: move to an empty area (e.g., (600,700)) — but that's on the svg background; hover release should restore. Then drag the node.

Execute: drag node 0 from (692,157) to (560,320).

Drag behavior check: node 0 moved to (560,330), links (to 9, 1, and bridges 30, 10) followed along, camera unchanged (zoom 1.04, other clusters remain at same screen positions). Hover state is still active during drag (pointer on node) — as expected.

Next: release and move away → hover is restored. Then pan the background: drag from (400,650) to (550,550). Confirm the graph moves and zoom stays at 1.04. Then wheel-zoom. Then reset.

First move the mouse to an empty spot to clear the hover: click on an empty area? Clicking on the background doesn't do anything harmful (zoom's click? no, no handler). But click = mousedown+up on background → zoom's pan is minimal. Use scroll? No, use key? Move via drag? The drag action drags. Simplest: do the pan drag starting from an empty area — this also clears hover at the same time (mouseleave fires when pointer leaves the node... during pan, pointer moves over background → mouseleave on node fires → restored).

Pan: drag (300,650) → (450,560).