Change galaxy layout to a 2:1 field and harden jump-network construction

- Replace the square star field with a wide (width × height) field whose aspect matches the map plate, so the fully-zoomed-out galaxy fills the plate instead of letterboxing; recompute zone edges for equal-area thirds under the new diagonal CDF. - Add fitPadded() in SystemChart.js and use it in GalaxyView.js to frame the galaxy as a true rectangle fit with a plate-pixel margin, replacing the old world-unit padding that left stars on the plate edge. - Rework the JumpNetwork spanning-tree heuristic to "save the stranded first" (attach the candidate with the fewest unvisited non-barren neighbors) and strengthen the repair pass: never attach to barren nodes, guard swaps against cycles via inSubtree(), and add a last-resort fallback that preserves strong connectivity. - Update tests (galaxy.test.mjs, system-chart.test.mjs) for the field bounds and the new fitPadded behavior; refresh README, PROJECT_NOTES, and data comments to document the 2:1 field and platePadding knob.
2026-09-08 14:51:19 -06:00 · 2026-09-08 14:51:19 -06:00 · 856508ff01
parent 5e4f94f385
commit 856508ff01
11 changed files with 217 additions and 99 deletions
--- a/README.md
+++ b/README.md
@ -36,7 +36,7 @@ node dev/server.mjs 8080
  (click it and type), and rerollable — and the menu shows what that seed
  builds (the galaxy's name, system count, archetype count) **before** you
  commit. Same seed ⇒ same galaxy.
- **Procedural galaxy**: 90 star systems in a seeded square field —
+- **Procedural galaxy**: 90 star systems in a seeded wide (2:1, plate-shaped) field —
  even, organic spacing (Poisson disk, `data/galaxy.json`), the player's
  home in the lower-right corner, and a home→far difficulty axis split
  into near/middle/far zones — typed into six themed archetypes
@ -188,7 +188,7 @@ orbit/
 │   ├── planets.json        #   home world + system layout + solid-disc rules
 │   ├── map.json            #   the MAP console: tabs, the system chart, the GALAXY tab (stars/pulse/lanes/region), stats, zoom
 │   ├── tether.json         #   the tether (your range): level radii, barrier line, glitch, contact
-│   ├── galaxy.json         #   galaxy scale & shape (count, square field, zones, corner home…)
+│   ├── galaxy.json         #   galaxy scale & shape (count, 2:1 field, zones, corner home…)
 │   ├── systems.json        #   system archetypes: theme, attributes, distribution
 │   ├── settlements.json    #   the lived-in layer: settlement kinds & populations
 │   ├── gates.json          #   JUMP GATES: network (1–3 gates, local jumps, pure spanning tree — maze, no shortcuts) + placement (tether anchor, facing, radii, gaps)
--- a/assets/videos/ss-surface-02.mp4
+++ b/assets/videos/ss-surface-02.mp4
--- a/data/galaxy.json
+++ b/data/galaxy.json
@ -1,18 +1,19 @@
 {
-  "_comment": "Galaxy shape + scale (js/galaxy/Galaxy.js). systemCount = total star systems (the starting system is one of them). layout.square = the galaxy is a seeded SQUARE field of stars (center at the world origin, ±side/2 in x and y): Bridson Poisson-disk sampling keeps every pair of systems at least minSpacing·√(side²/systemCount) apart — an even, organic field (no clumps, no voids, not a grid). startingSystem: policy 'corner' puts the player's home in the star NEAREST the configured corner (corner: NE/NW/SE/SW, screen orientation — SE = lower right); 'center' (nearest the origin) and 'random' still work. distribution.zones slices the HOME→FAR diagonal into named zones (d: 0 at the home corner, 1 at the opposite corner); distribution.zoneMix multiplies each type's distribution.weight PER ZONE (the old per-type radiusBand is gone — type flavor is regional now). settlements.gradient = free-space settlement density by diagonal position (d 0 = home corner, 1 = far corner): chance = 1 − d×falloff, floored at floor (js/galaxy/SystemGenerator.js → settlementDensity).",
+  "_comment": "Galaxy shape + scale (js/galaxy/Galaxy.js). systemCount = total star systems (the starting system is one of them). layout.field = the galaxy is a seeded WIDE (2:1) field of stars (center at the world origin, ±width/2 in x, ±height/2 in y — the 2:1 shape matches the map plate, js/ui/MapWindow.js at the 1280×720 design size, so the fully-zoomed-out galaxy fills the plate): Bridson Poisson-disk sampling keeps every pair of systems at least minSpacing·√(width·height/systemCount) apart — an even, organic field (no clumps, no voids, not a grid). startingSystem: policy 'corner' puts the player's home in the star NEAREST the configured corner (corner: NE/NW/SE/SW, screen orientation — SE = lower right); 'center' (nearest the origin) and 'random' still work. distribution.zones slices the HOME→FAR diagonal into named zones (d: 0 at the home corner, 1 at the opposite corner); distribution.zoneMix multiplies each type's distribution.weight PER ZONE (the old per-type radiusBand is gone — type flavor is regional now). settlements.gradient = free-space settlement density by diagonal position (d 0 = home corner, 1 = far corner): chance = 1 − d×falloff, floored at floor (js/galaxy/SystemGenerator.js → settlementDensity).",
  "systemCount": 90,
  "layout": {
-    "square": {
-      "side": 32000,
+    "field": {
+      "width": 32000,
+      "height": 16000,
      "minSpacing": 0.8
    }
  },
  "distribution": {
-    "_comment": "zones slice the HOME→FAR diagonal (d) into the three regions. The diagonal bands have UNEVEN area (corner triangles vs the middle band), so the edges are set for EQUAL-AREA thirds: area(d < a) = 2a² of the square for a ≤ ½ — a = 0.40 and 0.60 give ≈ 32/36/32. zoneMix multiplies each type's global distribution.weight per zone (missing type = ×1).",
+    "_comment": "zones slice the HOME→FAR diagonal (d) into the three regions. The diagonal bands have UNEVEN area (corner wedges vs the middle band), so the edges are set for EQUAL-AREA thirds: with half-extents (A, B) and d = (A²u + B²v)/(A²+B²) over uniform (u, v), the area CDF is f(t) = (t − β/2)/α with α = A²/(A²+B²), β = 1−α for the middle band — for the 2:1 field (α = 4/5) that's f(t) = 1.25t − 0.125, giving equal thirds at t = 11/30 ≈ 0.367 and 19/30 ≈ 0.633. Re-derive these edges if the field aspect changes. zoneMix multiplies each type's global distribution.weight per zone (missing type = ×1).",
    "zones": [
-      { "name": "near", "d": [0, 0.4] },
-      { "name": "middle", "d": [0.4, 0.6] },
-      { "name": "far", "d": [0.6, 1] }
+      { "name": "near", "d": [0, 0.37] },
+      { "name": "middle", "d": [0.37, 0.63] },
+      { "name": "far", "d": [0.63, 1] }
    ],
    "zoneMix": {
      "near": { "main": 1.0, "redDwarf": 1.25, "binary": 0.8, "habitable": 1.5, "nebula": 0.4, "void": 0.3 },
--- a/data/map.json
+++ b/data/map.json
@ -123,7 +123,8 @@
  "galaxy": {
    "_comment": "THE GALAXY TAB (js/ui/GalaxyView.js) — the whole-galaxy chart on the plate: one GLOWING STAR per system (colored by its archetype, data/systems.json → types, pulsing on that archetype's heartbeat in `pulse`), THIN LANES where the jump gates connect (the JumpNetwork spanning tree — a maze), the CHARTED REGION (the convex hull of the visited systems, inflated — the discovered-area shading), HOME + SHIP markers, ambient dust + the core glow. TRAVELED lanes (the run jumped them — saved with the run) glow brighter + carry a flow packet; FRONTIER lanes (one end visited) are the 'next step'; unexplored lanes are faint threads. Hover = the star's readout + its link state to the current system — STARS ONLY, and the zone hugs each star's drawn dot (glow radius + a few px of mouse pad), so the lanes between the stars never trigger it; click a CHARTED star = its chart in the SYSTEM tab; uncharted stars are readouts only. FACTIONS (planned, not yet implemented): the snapshot carries per-system `faction: null` — the reserved seams are a faction color layer over the stars + a per-faction territory region (the same hull/fill recipe as `hull`, per faction color + relation alpha).",
    "name": "GALAXY",
-    "padding": 90,
+    "platePadding": 26,
+    "_platePadding": "margin kept between the outermost stars and the plate edge at 1× zoom, in PLATE px (js/ui/GalaxyView.js → fitPadded). The field is 2:1 to match the plate, so the fully-zoomed-out galaxy fills the plate with this much breathing room on all sides.",
    "stars": {
      "_comment": "Per-system star rendering. minPx = the core dot at 1× zoom (a tad bigger than a pixel — the fully-zoomed-out dot); zoomGrow = px gained per zoom step (the star grows as you approach). glow/core = legacy world-unit bases (kept for the glow texture's swing). visitedBoost = how much brighter a charted star's glow reads; unknownMul/unknownAlpha = the dimmer read on uncharted stars (the galaxy is bigger than the run). art = the ZOOM-BLOOM design: the star is a plain dot until flareAt, then diffraction spikes fade in; at crownAt its type's signature appears (main = granulation rim + corona ticks, redDwarf = breathing corona + prominence arcs, binary = an orbiting companion on a faint ellipse, habitable = the life-zone rings + orbiting world(s), nebula = a tilted accretion disc + drifting speckles, void = a dark horizon + shimmering photon ring + lensing ticks); at surfaceAt the core gains a surface wobble + a glint. All sizes are × the dot; all angles/phases are seeded per system (deterministic); everything animates on scene time. spikes = 0 for the void (no sparkle around a horizon).",
      "glow": 30,
--- a/dev/galaxy.test.mjs
+++ b/dev/galaxy.test.mjs
@ -9,7 +9,7 @@
 *   - same seed ⇒ identical roster (ids, names, types, positions);
 *   - different seed ⇒ different galaxy;
 *   - type distribution matches the weights × per-zone mix (zoneMix, ±4σ);
- *   - square domain + even field (Poisson disk), every record carries d + zone;
+ *   - field bounds + even field (Poisson disk), every record carries d + zone;
 *   - starting system = the star nearest the configured home corner;
 *   - every generated system obeys its type's attribute bounds;
 *   - the OBJECT COMPOSITION (data/systems.json → objectCount): every
@ -158,18 +158,18 @@ let big;
  }
  check('type distribution matches configured weights × zoneMix per zone (±4σ)', distOk);

-  // SQUARE DOMAIN + EVEN FIELD + DIFFICULTY COORDINATE (the layout contract).
-  const side = Math.max(2, Math.floor(Number(big.params.layout?.square?.side) || 32000));
-  const half = side / 2;
+  // FIELD BOUNDS + EVEN FIELD + DIFFICULTY COORDINATE (the layout contract).
+  const fieldW = Math.max(2, Math.floor(Number(big.params.layout?.field?.width) || 32000));
+  const fieldH = Math.max(2, Math.floor(Number(big.params.layout?.field?.height) || 16000));
  check(
-    'every system sits inside the square domain (±side/2)',
-    big.records.every((r) => Math.abs(r.x) <= half + 1e-9 && Math.abs(r.y) <= half + 1e-9),
+    'every system sits inside the 2:1 field (±width/2 × ±height/2)',
+    big.records.every((r) => Math.abs(r.x) <= fieldW / 2 + 1e-9 && Math.abs(r.y) <= fieldH / 2 + 1e-9),
  );
  let minPair = Infinity;
  for (let i = 0; i < big.records.length; i++)
    for (let j = i + 1; j < big.records.length; j++)
      minPair = Math.min(minPair, Math.hypot(big.records[i].x - big.records[j].x, big.records[i].y - big.records[j].y));
-  const spacingFloor = 0.7 * Math.sqrt((side * side) / big.records.length);
+  const spacingFloor = 0.7 * Math.sqrt((fieldW * fieldH) / big.records.length);
  check(
    `even field (Poisson disk): min pair distance ${Math.round(minPair)} px ≥ ${Math.round(spacingFloor)} px — no clumps, no voids`,
    minPair >= spacingFloor - 1e-6,
@ -187,7 +187,7 @@ let big;
  );
  // CORNER HOME (startingSystem.policy 'corner', corner SE — lower right,
  // screen y-down): the starting system is the star NEAREST the home corner.
-  const homeCorner = { x: half, y: half };
+  const homeCorner = { x: fieldW / 2, y: fieldH / 2 };
  const nearestToCorner = big.records
    .slice()
    .sort((a, b) => (a.x - homeCorner.x) ** 2 + (a.y - homeCorner.y) ** 2 - ((b.x - homeCorner.x) ** 2 + (b.y - homeCorner.y) ** 2))[0].id;
@ -289,10 +289,11 @@ let big;
  // The CORNER policy honors whichever corner is configured (here: NW —
  // upper left, screen y-down), not just the default SE.
  const nw = Galaxy.create('nw-policy', { systemCount: 250, startingSystem: { policy: 'corner', corner: 'NW' } });
-  const halfNW = Math.max(2, Math.floor(Number(nw.params.layout?.square?.side) || 32000)) / 2;
+  const halfNWx = Math.max(2, Math.floor(Number(nw.params.layout?.field?.width) || 32000)) / 2;
+  const halfNWy = Math.max(2, Math.floor(Number(nw.params.layout?.field?.height) || 16000)) / 2;
  const trueNW = nw.records
    .slice()
-    .sort((a, b) => (a.x + halfNW) ** 2 + (a.y + halfNW) ** 2 - ((b.x + halfNW) ** 2 + (b.y + halfNW) ** 2))[0].id;
+    .sort((a, b) => (a.x + halfNWx) ** 2 + (a.y + halfNWy) ** 2 - ((b.x + halfNWx) ** 2 + (b.y + halfNWy) ** 2))[0].id;
  check('corner policy honors the configured corner (NW)', nw.currentSystemId === trueNW);
 }

--- a/dev/system-chart.test.mjs
+++ b/dev/system-chart.test.mjs
@ -17,7 +17,7 @@
 *   - resourceStats: the SYSTEM RESOURCES share over the asteroid fields
 *     (content.asteroids) — found/total + pct; missing list → 0/0.
 */
-import { chartBounds, fitToRect, navDiscoveryStats, resourceStats, systemChartSnapshot } from '../js/galaxy/SystemChart.js';
+import { chartBounds, fitPadded, fitToRect, navDiscoveryStats, resourceStats, systemChartSnapshot } from '../js/galaxy/SystemChart.js';

 let passed = 0;
 let failed = 0;
@ -91,6 +91,29 @@ console.log('fitToRect');
  ok(near(tf.toX(100) - tf.toX(-100), 200), 'frame width preserved');
 }

+// ── fitPadded (the galaxy plate's framing) ────────────────────────────────
+console.log('fitPadded');
+{
+  // a 2:1 box into the 2:1 map plate (830.7×414 at the 1280×720 design
+  // size) with a 26-plate-px margin — a TRUE rectangle fit: the
+  // constrained axis fills the plate minus exactly padPx, the other axis
+  // keeps ≥ padPx. (fitToRect would inscribe the box's bounding square
+  // and leave most of the plate empty.)
+  const bounds = { minX: -100, minY: -50, maxX: 100, maxY: 50, w: 200, h: 100, cx: 0, cy: 0 };
+  const f = fitPadded(bounds, 830.7, 414, 26);
+  ok(near(f.scale, Math.min(778.7 / 200, 362 / 100)), 'scale = min((w−2p)/bw, (h−2p)/bh)');
+  ok(near(f.scale * 100, 362, 1e-6) && f.scale * 200 <= 778.7 + 1e-6, 'constrained axis fills plate−margin; the other axis stays inside');
+  ok(near(f.scale * f.bounds.h, 414, 1e-6), 'inflated bounds (the pan/zoom clamp) reach exactly the plate edge on the constrained axis — the margin survives panning');
+  ok(f.scale * f.bounds.w <= 830.7 + 1e-6, '...and never overflow the plate');
+  ok(near(f.bounds.cx, 0) && near(f.bounds.cy, 0), 'centre preserved');
+}
+{
+  // zero padding → plain true rectangle fit
+  const bounds = { minX: 0, minY: 0, maxX: 100, maxY: 100, w: 100, h: 100, cx: 50, cy: 50 };
+  const f = fitPadded(bounds, 830, 414, 0);
+  ok(near(f.scale, 414 / 100), 'square bounds into a wide plate: limited by the shorter side (like fitToRect)');
+}
+
 // ── navDiscoveryStats ──────────────────────────────────────────────────────
 console.log('navDiscoveryStats');
 {
--- a/docs/PROJECT_NOTES.md
+++ b/docs/PROJECT_NOTES.md
@ -132,10 +132,13 @@ menu (displayed, editable, rerollable; same seed ⇒ same galaxy).
  nearest stars, tie-broken by a derived seeded Rng. The stamps land on
  each planet record (`planet.frame`) and the home world's face on
  `content.homeFrame`, read by `GameScene`. Verified: `dev/frames.test.mjs`.
- **distributed** — a seeded SQUARE field of stars
-  (`galaxy.layout.square`: `side`, `minSpacing`) placed by Bridson
-  Poisson-disk sampling — even, organic spacing (no clumps, no voids,
-  not a grid). The player's home sits in the star NEAREST the configured
+- **distributed** — a seeded WIDE (2:1) field of stars
+  (`galaxy.layout.field`: `width`, `height`, `minSpacing`) placed by
+  Bridson Poisson-disk sampling — even, organic spacing (no clumps, no
+  voids, not a grid). The 2:1 shape matches the map plate (830×414 at
+  the 1280×720 design size), and the plate fit is a true rectangle fit
+  with a plate-px margin on all sides (`map.galaxy.platePadding`) — the
+  fully-zoomed-out galaxy fills the plate and no star sits on its edge. The player's home sits in the star NEAREST the configured
  corner (`startingSystem: policy "corner"`, `corner: SE` = lower right;
  `center`/`random` still work), and the HOME→FAR diagonal is the
  progression axis: every record carries `d` (0 = home corner, 1 = far
@ -1276,7 +1279,7 @@ The player holds a REPUTATION (standing) on each planet and space station:
      capacities; upgrades (ship-category builds) will layer deltas on top
 - [ ] Ship screen (the Ship slot) — inspect & upgrade the ship
      (ship-category builds) from one place
- [x] Galaxy regions: square field + home→far `d` coordinate +
+- [x] Galaxy regions: wide 2:1 field (plate-shaped) + home→far `d` coordinate +
      near/middle/far zones + per-zone type mix (data/galaxy.json →
      distribution.zones/zoneMix) — the region layer is live
 - [ ] Factions: Voronoi territories around seeded capitals → each
--- a/js/galaxy/Galaxy.js
+++ b/js/galaxy/Galaxy.js
@ -29,10 +29,13 @@ const clamp = (v, lo, hi) => Math.min(hi, Math.max(lo, v));
 *     `generateAll()` exists for exactly that, if it's ever "just as easy".
 *
 * The SHAPE (data/galaxy.json):
- *   - a seeded SQUARE field of stars (layout.square.side, center at the
- *     world origin) placed by Bridson Poisson-disk sampling — an even,
- *     organic field: every pair of systems stays at least
- *     minSpacing·√(side²/N) apart, no clumps, no voids, not a grid;
+ *   - a seeded WIDE (2:1) field of stars (layout.field.width × height,
+ *     center at the world origin) placed by Bridson Poisson-disk
+ *     sampling — an even, organic field: every pair of systems stays at
+ *     least minSpacing·√(width·height/N) apart, no clumps, no voids, not
+ *     a grid. The 2:1 aspect matches the map plate (js/ui/MapWindow.js at
+ *     the 1280×720 design size), so the fully-zoomed-out galaxy fills
+ *     the plate instead of letterboxing;
 *   - the player's HOME system sits in the star nearest the configured
 *     corner (startingSystem: policy "corner", corner NE/NW/SE/SW,
 *     screen orientation — SE = lower right); "center" / "random" still
@ -55,7 +58,7 @@ const clamp = (v, lo, hi) => Math.min(hi, Math.max(lo, v));
 *   - COMBAT / TRADE: read difficulty and price levels off `record.d`
 *     and `record.zone` (the middle zone is where the zone borders cross
 *     — the planned contested space + transit trade hubs).
- *   - more layout knobs in data/galaxy.json `layout.square`.
+ *   - more layout knobs in data/galaxy.json `layout.field`.
 */
 export class Galaxy {
  constructor(seed, params, typeDefs) {
@ -109,11 +112,14 @@ export class Galaxy {

  _generate(count) {
    const L = this.params.layout ?? {};
-    const SQ = L.square ?? {};
-    const S = Math.max(2, Math.floor(Number(SQ.side) || 32000));
-    this.side = S; // the square domain's edge (world px, center at origin)
-    const half = S / 2;
-    const minSpacing = clamp(Number(SQ.minSpacing) || 0.8, 0.4, 1.2);
+    const F = L.field ?? {};
+    const W = Math.max(4, Math.floor(Number(F.width) || 32000));
+    const H = Math.max(4, Math.floor(Number(F.height) || 16000));
+    this.fieldW = W; // the field's extent (world px, center at origin)
+    this.fieldH = H;
+    const halfW = W / 2;
+    const halfH = H / 2;
+    const minSpacing = clamp(Number(F.minSpacing) || 0.8, 0.4, 1.2);

    // The HOME CORNER (data/galaxy.json → startingSystem.corner; screen
    // orientation — y down, so SE = lower right). Two things key off it:
@ -122,9 +128,9 @@ export class Galaxy {
    // corner — the galaxy's progression axis, whatever policy picks the
    // starting system).
    const start = this.params.startingSystem ?? {};
-    const corner = this._cornerPoint(start.corner ?? 'SE', half);
+    const corner = this._cornerPoint(start.corner ?? 'SE', { halfW, halfH });
    const opp = { x: -corner.x, y: -corner.y };
-    const diag2 = (corner.x - opp.x) ** 2 + (corner.y - opp.y) ** 2; // 2·S²
+    const diag2 = (corner.x - opp.x) ** 2 + (corner.y - opp.y) ** 2; // W² + H²
    const dOf = (x, y) => clamp(
      ((corner.x - x) * (corner.x - opp.x) + (corner.y - y) * (corner.y - opp.y)) / diag2,
      0, 1,
@ -153,17 +159,18 @@ export class Galaxy {
    // EVEN PLACEMENT — a Bridson Poisson-disk (blue-noise) field: every
    // pair of systems stays at least dmin apart (no clumps, no voids)
    // while the field stays organic (not a grid). dmin is a fraction of
-    // the mean inter-star spacing √(side²/N) (layout.square.minSpacing).
+    // the mean inter-star spacing √(width·height/N)
+    // (layout.field.minSpacing).
    // Even spacing is what keeps the jump network's hop counts
    // proportional to map distance — the property the trade economy
    // leans on ("a hop is a hop").
-    const dmin = minSpacing * Math.sqrt((S * S) / Math.max(1, count));
-    const points = this._poissonDisk(count, half, dmin);
+    const dmin = minSpacing * Math.sqrt((W * H) / Math.max(1, count));
+    const points = this._poissonDisk(count, { halfW, halfH }, dmin);

    const records = this.records;
    for (let i = 1; i <= count; i++) {
      const id = `S${String(i).padStart(6, '0')}`;
-      const p = points[i - 1] ?? { x: g.range(-half, half), y: g.range(-half, half) };
+      const p = points[i - 1] ?? { x: g.range(-halfW, halfW), y: g.range(-halfH, halfH) };
      const d = dOf(p.x, p.y);
      const zone = zoneOf(d);
      const type = g.weighted(weightsFor(zone), typeIds[0]);
@ -195,7 +202,7 @@ export class Galaxy {

    // Spatial hash for fast neighbor queries (jump ranges, proximity rules,
    // the eventual star map).
-    const area = S * S;
+    const area = W * H;
    this.cellSize = Math.max(8, Math.sqrt(area / count) * 1.4);
    this.grid = new Map();
    for (const rec of records) {
@ -308,56 +315,58 @@ export class Galaxy {
    return out.length ? out : [{ name: 'all', d: [0, 1] }];
  }

-  /** A corner of the square domain (screen orientation — y DOWN). */
-  _cornerPoint(name, half) {
+  /** A corner of the field (screen orientation — y DOWN). */
+  _cornerPoint(name, { halfW, halfH }) {
    const CORNERS = { NE: [1, -1], NW: [-1, -1], SE: [1, 1], SW: [-1, 1] };
    const key = String(name ?? 'SE').toUpperCase();
    const [sx, sy] = CORNERS[key] ?? CORNERS.SE;
-    return { x: sx * half, y: sy * half };
+    return { x: sx * halfW, y: sy * halfH };
  }

  /**
-   * Even star placement: exactly `n` points in the square [−half, half]²,
-   * every pair at least `d0` apart (Bridson / Poisson disk). If the disk
-   * can't hold `n` points at `d0` (dense config), retry a few times with
-   * a relaxed spacing; as a last resort pad with random points — a working
-   * galaxy beats a perfect one. Deterministic: each attempt draws from its
-   * own seeded fork (seed, 'layout', 'poisson', attempt).
+   * Even star placement: exactly `n` points in the field
+   * [−halfW, halfW] × [−halfH, halfH], every pair at least `d0` apart
+   * (Bridson / Poisson disk). If the field can't hold `n` points at
+   * `d0` (dense config), retry a few times with a relaxed spacing; as a
+   * last resort pad with random points — a working galaxy beats a
+   * perfect one. Deterministic: each attempt draws from its own seeded
+   * fork (seed, 'layout', 'poisson', attempt).
   */
-  _poissonDisk(n, half, d0) {
+  _poissonDisk(n, { halfW, halfH }, d0) {
    if (n <= 0) return [];
    let d = Math.max(1, d0);
    let pts = null;
    for (let attempt = 0; attempt < 8; attempt++) {
      const rng = Rng.derive(this.seed, 'layout', 'poisson', attempt);
-      pts = this._bridson(n, half, d, rng);
+      pts = this._bridson(n, { halfW, halfH }, d, rng);
      if (pts.length >= n) break;
      d *= 0.88; // not enough room — loosen the spacing and retry
    }
    const rng = Rng.derive(this.seed, 'layout', 'poisson', 'pad');
    while (pts.length < n) {
-      pts.push({ x: rng.range(-half, half), y: rng.range(-half, half) });
+      pts.push({ x: rng.range(-halfW, halfW), y: rng.range(-halfH, halfH) });
    }
    return pts.slice(0, n);
  }

  /**
-   * Bridson's algorithm: grow a Poisson-disk of points in the square,
+   * Bridson's algorithm: grow a Poisson-disk of points in the field,
   * stopping once `n` points are placed (or the frontier is exhausted).
-   * Pure — deterministic for a given (n, half, d, rng stream).
+   * Pure — deterministic for a given (n, halfW, halfH, d, rng stream).
   */
-  _bridson(n, half, d, rng) {
+  _bridson(n, { halfW, halfH }, d, rng) {
    if (n <= 0) return [];
    const cell = d / Math.SQRT2;
    const grid = new Map(); // "cx,cy" → [point, …]
    const pts = [];
    const active = []; // indices into pts (Bridson's active list)
-    const inside = (p) => p.x >= -half && p.x <= half && p.y >= -half && p.y <= half;
+    const inside = (p) =>
+      p.x >= -halfW && p.x <= halfW && p.y >= -halfH && p.y <= halfH;
    const keyOf = (p) =>
-      `${Math.floor((p.x + half) / cell)},${Math.floor((p.y + half) / cell)}`;
+      `${Math.floor((p.x + halfW) / cell)},${Math.floor((p.y + halfH) / cell)}`;
    const free = (p) => {
-      const cx = Math.floor((p.x + half) / cell);
-      const cy = Math.floor((p.y + half) / cell);
+      const cx = Math.floor((p.x + halfW) / cell);
+      const cy = Math.floor((p.y + halfH) / cell);
      for (let ax = -2; ax <= 2; ax++) {
        for (let ay = -2; ay <= 2; ay++) {
          const bucket = grid.get(`${cx + ax},${cy + ay}`);
@ -380,7 +389,7 @@ export class Galaxy {
      else grid.set(k, [p]);
    };
    // Seed the frontier with one random interior point.
-    place({ x: rng.range(-half, half), y: rng.range(-half, half) });
+    place({ x: rng.range(-halfW, halfW), y: rng.range(-halfH, halfH) });
    while (active.length > 0 && pts.length < n) {
      const i = rng.int(0, active.length - 1);
      const p = pts[active[i]];
@ -418,7 +427,7 @@ export class Galaxy {
      best.sort((a, b) => a.d2 - b.d2);
      if (best.length > k) best.length = k;
    };
-    const maxRing = Math.min(1024, Math.ceil((Math.SQRT2 * (this.side ?? 40000)) / c) + 1);
+    const maxRing = Math.min(1024, Math.ceil(Math.hypot(this.fieldW ?? 32000, this.fieldH ?? 16000) / c) + 1);
    for (let ring = 0; ring <= maxRing; ring++) {
      for (let dx = -ring; dx <= ring; dx++) {
        for (let dy = -ring; dy <= ring; dy++) {
--- a/js/galaxy/JumpNetwork.js
+++ b/js/galaxy/JumpNetwork.js
@ -27,11 +27,14 @@
 * Construction:
 *   1. The undirected neighbor graph (u~v iff v ∈ nn(u) or u ∈ nn(v)).
 *   2. A spanning tree of it with every node's degree ≤ maxGates, grown
- *      BFS-outward from the home system with a "keep the frontier open"
- *      child heuristic: attach the unvisited neighbors with the MOST
- *      unvisited neighbors first, so rim clusters are absorbed before
- *      their degree budget is spent. A BARREN node never adopts children
- *      (it keeps its single gate — the maze's dead end).
+ *      BFS-outward from the home system with a "save the stranded first"
+ *      child heuristic: attach the unvisited neighbor with the FEWEST
+ *      unvisited non-barren neighbors (its other possible adopters)
+ *      first — a star nobody else can adopt must not wait for a budget
+ *      slot. Ties keep the "keep the frontier open" order (most unvisited
+ *      neighbors first — they grow the tree for others). A BARREN node
+ *      never adopts children (it keeps its single gate — the maze's
+ *      dead end).
 *   3. Tree edges run BOTH ways. A bidirected tree is strongly connected
 *      by construction (the unique tree path between any two systems can
 *      be walked in either direction), and every node's gate count is its
@ -46,8 +49,10 @@
 *
 * The repair pass (below) is defensive: it fires only if the neighbor
 * graph is disconnected (effectively impossible at this scale), and it
- * still respects the degree budget (preferring non-barren attach targets
- * so a dead end stays a leaf when it can).
+ * NEVER breaks the invariants: it only ever attaches to NON-BARREN nodes
+ * (a dead end keeps its single gate — even in repair), and its swap
+ * option re-homes a child onto a node outside the child's own subtree
+ * (the tree stays a tree).
 */

 /**
@ -133,14 +138,23 @@ export function buildJumpNetwork({
    if (budget <= 0) continue;
    const cands = nbr[u].filter((v) => !visited[v]);
    if (cands.length === 0) continue;
-    // "Keep the frontier open": candidates with the most unvisited
-    // neighbors grow the tree for others; ties by index (determinism).
+    // "Save the stranded first": attach the candidate with the FEWEST
+    // unvisited non-barren neighbors — those are the stars no one else
+    // can adopt (barren leaves never adopt; claimed nodes can't), and
+    // letting them wait is how pockets strand. Ties keep the old
+    // "keep the frontier open" order (most unvisited neighbors first —
+    // they grow the tree for others), then index (determinism).
    const scored = cands.map((v) => {
+      let risk = 0; // unvisited NON-BARREN neighbors of v (its other adopters)
      let unv = 0;
-      for (const w of nbr[v]) if (!visited[w]) unv++;
-      return { v, unv };
+      for (const w of nbr[v]) {
+        if (visited[w]) continue;
+        unv++;
+        if (!isBarren(w)) risk++;
+      }
+      return { v, risk, unv };
    });
-    scored.sort((a, b) => b.unv - a.unv || a.v - b.v);
+    scored.sort((a, b) => a.risk - b.risk || b.unv - a.unv || a.v - b.v);
    for (const { v } of scored.slice(0, budget)) {
      visited[v] = 1;
      parent[v] = u;
@ -153,30 +167,44 @@ export function buildJumpNetwork({
  // --- Repair (defensive): attach anything the tree left behind ---------
  // A leftover node has no visited neighbor with spare degree (its whole
  // neighborhood sat in a disconnected pocket). Repair, in order of
-  // preference (all deterministic — index order, strict comparisons):
-  //   1. Attach to a visited neighbor with spare degree (local).
+  // preference (all deterministic — index order, strict comparisons). A
+  // barren node is NEVER an attach target — a dead end keeps its single
+  // gate, even in repair:
+  //   1. Attach to a visited NON-BARREN neighbor with spare degree (local).
  //   2. SWAP: take one of a visited node u's tree children x, re-home x
-  //      onto one of x's OWN visited neighbors that has spare degree, and
-  //      use the freed budget for w. The tree stays a tree; locality is
+  //      onto one of x's OWN visited NON-BARREN neighbors that has spare
+  //      degree (and sits outside x's own subtree — no cycles), and use
+  //      the freed budget for w. The tree stays a tree; locality is
  //      preserved (x stays inside its own neighborhood).
  //   3. Last resort (should never fire on a kNN graph): attach w to the
-  //      nearest visited node and accept one over-budget degree — a working
-  //      network beats a broken one.
+  //      nearest visited NON-BARREN node and accept one over-budget degree
+  //      — a working network beats a broken one.
  const dist2 = (a, b) => {
    const dx = records[a].x - records[b].x;
    const dy = records[a].y - records[b].y;
    return dx * dx + dy * dy;
  };
  let repaired = 0;
+  // Is `a` inside `anc`'s subtree (a ≠ anc)? — the swap must not re-home
+  // a child onto one of its own descendants (that would close a cycle).
+  const inSubtree = (a, anc) => {
+    let p = parent[a];
+    while (p >= 0) {
+      if (p === anc) return true;
+      p = parent[p];
+    }
+    return false;
+  };
  for (let w = 0; w < n; w++) {
    if (visited[w]) continue;
-    // (1) local attach — prefer a non-barren target (a dead end should
-    // keep its single gate when the graph lets us).
+    // (1) local attach — a barren neighbor is NEVER a target: a dead end
+    // keeps its single gate, even in repair.
    let u = -1;
    for (const c of nbr[w]) if (visited[c] && deg[c] < maxGates && !isBarren(c)) { u = c; break; }
-    if (u === -1) for (const c of nbr[w]) if (visited[c] && deg[c] < maxGates) { u = c; break; }
    if (u === -1) {
-      // (2) swap: best (u, x) pair by dist(w, u), then indices
+      // (2) swap: best (u, x) pair by dist(w, u), then indices. The new
+      // parent (bestNew) must have spare degree, be non-barren, and sit
+      // outside x's subtree.
      let bestU = -1, bestX = -1, bestNew = -1, bestD = Infinity;
      for (let c = 0; c < n; c++) {
        if (!visited[c] || c === w || deg[c] < 2) continue; // needs a child to free
@ -186,7 +214,9 @@ export function buildJumpNetwork({
        for (let x = 0; x < n; x++) {
          if (parent[x] !== c) continue;
          for (const nn of nbr[x]) {
-            if (nn === c || nn === w || !visited[nn] || deg[nn] >= maxGates) continue;
+            if (nn === c || nn === w || nn === x) continue;
+            if (!visited[nn] || isBarren(nn) || deg[nn] >= maxGates) continue;
+            if (inSubtree(nn, x)) continue; // re-homing here would close a cycle
            if (d < bestD || (d === bestD && (c < bestU || (c === bestU && x < bestX)))) {
              bestD = d; bestU = c; bestX = x; bestNew = nn;
            }
@ -201,18 +231,26 @@ export function buildJumpNetwork({
      }
    }
    if (u === -1) {
-      // (3) nearest visited node, budget be damned (prefer non-barren)
+      // (3) nearest visited NON-BARREN node, budget be damned
      let bestD = Infinity;
-      for (const pass of [1, 0]) {
+      let found = -1;
+      for (let c = 0; c < n; c++) {
+        if (!visited[c] || c === w || isBarren(c)) continue;
+        const d = dist2(w, c);
+        if (d < bestD) { bestD = d; found = c; }
+      }
+      if (found === -1) {
+        // (4) truly nothing else (effectively unreachable on a kNN graph):
+        // strong connectivity beats the leaf invariant — take ANY visited
+        // node, budget be damned.
        for (let c = 0; c < n; c++) {
          if (!visited[c] || c === w) continue;
-          if (Boolean(isBarren(c)) !== (pass === 1)) continue;
          const d = dist2(w, c);
-          if (d < bestD) { bestD = d; u = c; }
+          if (d < bestD) { bestD = d; found = c; }
        }
-        if (u !== -1) break;
      }
-      if (u === -1) continue; // nothing to attach to (n === 1 handled above)
+      if (found === -1) continue; // nothing to attach to (n === 1 handled above)
+      u = found;
      console.warn(`[orbit] jump network: forced attach of ${records[w].id} (degree budget exceeded)`);
    }
    visited[w] = 1;
--- a/js/galaxy/SystemChart.js
+++ b/js/galaxy/SystemChart.js
@ -97,6 +97,39 @@ export function fitToRect(bounds, w = 100, h = 100) {
  };
 }

+/**
+ * fitPadded(bounds, w, h, padPx) — fit `bounds` (the chartBounds() shape)
+ * into a w×h plate with `padPx` of margin on ALL four sides, measured in
+ * PLATE pixels (not world units — world padding is meaningless for a
+ * 32k-wide galaxy field): the scale that leaves exactly padPx at each
+ * edge is s = min((w−2p)/bw, (h−2p)/bh) — a TRUE rectangle fit (fitToRect
+ * inscribes the bounds' bounding square instead, so it only fills a plate
+ * whose aspect matches a square's). Returns { scale, bounds } where
+ * bounds is the ORIGINAL box inflated by padPx/scale in world units —
+ * feed THAT inflated box to the pan/zoom clamp so the drawn content
+ * never touches the plate edge, even at the clamped extremes.
+ */
+export function fitPadded(bounds, w = 100, h = 100, padPx = 0) {
+  const bw = Math.max(1e-6, (bounds?.maxX ?? 0) - (bounds?.minX ?? 0));
+  const bh = Math.max(1e-6, (bounds?.maxY ?? 0) - (bounds?.minY ?? 0));
+  const p = Math.max(0, Number(padPx) || 0);
+  const scale = Math.min((w - 2 * p) / bw, (h - 2 * p) / bh);
+  const padW = p / scale;
+  return {
+    scale,
+    bounds: {
+      minX: bounds.minX - padW,
+      minY: bounds.minY - padW,
+      maxX: bounds.maxX + padW,
+      maxY: bounds.maxY + padW,
+      cx: bounds.cx,
+      cy: bounds.cy,
+      w: bw + 2 * padW,
+      h: bh + 2 * padW,
+    },
+  };
+}
+
 /**
 * The SYSTEM DISCOVERY share (data/map.json → stats): the player's found /
 * total over the system's NAV objects — planets, free-space stations and
--- a/js/ui/GalaxyView.js
+++ b/js/ui/GalaxyView.js
@ -65,7 +65,7 @@ import { fontStack, themeColor } from '../utils/Theme.js';
 import { setInteractiveEnabled } from '../utils/Input.js';
 import { canvasTexture } from '../utils/Textures.js';
 import { Rng } from '../utils/Rng.js';
-import { chartBounds, fitToRect } from '../galaxy/SystemChart.js';
+import { chartBounds, fitPadded } from '../galaxy/SystemChart.js';
 import { paddedHullPolygon, starPulse, starTypeColor, clipLineToRect, clipPolygonToRect, starDotPx, starArtSpec } from '../galaxy/GalaxyChart.js';

 const TAU = Math.PI * 2;
@ -334,14 +334,23 @@ export class GalaxyView {
    const first = this._snap == null;
    this._snap = snap;
    if (first) {
-      // frame + fit (world → plate), like the system chart
+      // frame + fit (world → plate), like the system chart — but a TRUE
+      // rectangle fit with a PLATE-PIXEL margin on all four sides
+      // (map.galaxy.platePadding): the field is 2:1 to match the plate, so
+      // it fills the plate at 1× instead of letterboxing, and the old
+      // 90-WORLD-unit padding (negligible on a 32k field — the stars sat
+      // on the plate edges) is a 26-plate-px margin. The inflated bounds
+      // drive the pan/zoom clamp, so the stars keep that margin even when
+      // panned to the edge.
      const glowW = Math.max(10, Number(this._cfg.stars.glow ?? 30));
-      const pad = Number(config.get('map.galaxy.padding', 90)) || 90;
-      this._bounds = chartBounds(
+      const platePad = Number(config.get('map.galaxy.platePadding', 26)) || 26;
+      const b0 = chartBounds(
        snap.systems.map((s) => ({ x: s.x, y: s.y, radius: glowW / 2 })),
-        pad
+        0
      );
-      this._fit = fitToRect(this._bounds, this.pw, this.ph);
+      const fit = fitPadded(b0, this.pw, this.ph, platePad);
+      this._bounds = fit.bounds;
+      this._fit = { scale: fit.scale, cx: fit.bounds.cx, cy: fit.bounds.cy };
      this._view = { z: 1, cx: this._bounds.cx, cy: this._bounds.cy };
      // charted-region inflation, in WORLD units (a fraction of the plate
      // width at 1× zoom) — stable across zoom levels