地图集图页：编号地图与一幅转向的总图

// ═══ Postext Cookbook · Nº 067 · Atlas sheet: numbered maps and a rotated overview ═════
// https://postext.dev/en/cookbook/atlas-map-sheet
// Code: MIT · Text: original (CC BY 4.0) · Maps: generated in code from seed 1874 (CC BY 4.0)
// Fonts: Marcellus, Alegreya Sans, Alegreya Sans SC (SIL OFL 1.1) · Needs postext ≥ 1.4.1
import {
  buildDocument, renderPageToCanvas, clearMeasurementCache, registerResourceImage,
  defaultResourceTypes, setCellBackground, setAlignment,
} from 'https://esm.sh/postext';

const LANG = 'en'; // @lang: the language of the sample document ('en' | 'es')
const RECIPE = 'atlas-map-sheet';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: the page's colours and the maps' tints, one object for both
const palette = {
  ink: '#23282b', paper: '#fbfaf6', // a blue-black on a warm white
  band: '#1f4a5c', // the accent: opener band, caption bars, table head, references
  road: '#b2432f', // the second colour: roads, lights and the place numbers
  muted: '#626a6d', rule: '#c8c2b4', // running heads and notes; hairlines
  deep: '#8fb9c6', sea: '#cfe3e8', // the maps' water: over and under 20 m
  land: '#efe6cf', hill1: '#d9c9a3', hill2: '#bfa97a', forest: '#7f9b6a', // and their land
};
// col(id) links a colour to its entry. It carries the hex too: 1.4.1 paints design elements
// and the reference colour from the hex (gotcha: palette-skips-designs).
const col = (id) => ({ hex: palette[id], model: 'hex', paletteId: id });
const colorPalette = Object.entries({ ...palette, 'main-color': palette.band }) // the defaults' id
  .map(([id, hex]) => ({ id, name: id, value: { hex, model: 'hex' } }));
// #endregion
const [TEXT, DISPLAY, LABEL] = ['Alegreya Sans', 'Marcellus', 'Alegreya Sans SC'];
const PAGE = { w: 230, h: 300, top: 22, bottom: 22, inner: 18, outer: 16 }; // mm, mirrored
const LEAD = 13.5; // pt: the body's leading and baseline grid
const PT = 25.4 / 72; // mm in a point

// #region answer: a Map type captioned on a bar above the drawing, and where each map goes
// Every caption stands above its drawing or table, in the label face. Maps count 1, 2, 3…
// through the atlas as a type of their own and set their caption on a bar in the band colour.
const captionStyle = { fontFamily: LABEL, fontSize: pt(9), labelColor: col('band'),
  position: 'above', gap: mm(1.6), note: { fontSize: pt(7.8), color: col('muted') } };
const MAP_WORD = t({ en: 'Map', es: 'Mapa' });
const mapType = { id: 'map', name: MAP_WORD, shortLabel: MAP_WORD, captionPrefix: MAP_WORD,
  numberingTemplate: '{n}', resetOn: 'never', counterFormat: 'decimal',
  captionStyle: { backgroundEnabled: true, background: col('band'), color: col('paper'),
    labelColor: col('paper'), padding: mm(1.4) } }; // the bar only; the rest is captionStyle's
// Each map floats from its first :ref to the first slot its placement allows.
const PLACEMENT = {
  relief: { position: 'bottom', span: 'page' }, // the foot of the page that cites it
  north: { position: 'top' }, // the head of the next free column
  harbour: { position: 'top' },
  chart: { rotate: 'ccw' }, // turned a quarter, top to the left, on a page of its own
};
// Drawing sizes in mm. Turned, the chart is laid out along 247.6 mm, the text area's 53 grid
// lines less one for the float gap; the bar and the note leave 182.2 mm of the 196 mm measure.
const MAP = { relief: [196, 136], north: [95, 88], harbour: [95, 88], chart: [247.6, 182.2] };
// #endregion

// #region legend: the tints of the maps, and a key of swatches drawn from the same ids
// The bands the maps are filled with, lowest first. Art and key share each palette id, so one hex
// changes both; the unit is spelled out once, since the small caps print an m as an M.
const RELIEF = [
  { id: 'deep', en: 'sea over 20', es: 'mar de más de 20' },
  { id: 'sea', from: -20, en: 'sea under 20', es: 'de menos de 20' },
  { id: 'land', from: 0, en: 'land to 50', es: 'tierra hasta 50' },
  { id: 'hill1', from: 50, en: '50–120', es: '50–120' },
  { id: 'hill2', from: 120, en: 'over 120', es: 'más de 120' },
  { id: 'forest', en: 'woodland', es: 'bosque' },
];
const legend = t({ en: 'In metres: ', es: 'En metros: ' }) // a thin space more after each swatch
  + RELIEF.map((band) => `:swatch{color="${band.id}"} \u2009${t(band)}`).join(' · ');
// #endregion

// #region opener: the atlas's name on a band of deep sea, the sheet in its kicker
const BAND = 80; // mm from the trim to the foot of the band
const AIR = 7; // mm at least between the band and the first line of text
const ROSE = 50; // mm across the compass rose
const pin = (to, edge, x, y, size) => ({ anchor: { to, edge }, offset: { x: mm(x), y: mm(y) },
  ...(size && { size }) }); // to: 'page', 'bleed' or '#id' of an element listed before
const text = (id, content, family, size, color, placement, extra) => ({ kind: 'text', id,
  content, fontFamily: family, fontSize: pt(size), color: col(color), align: 'left',
  overflow: 'wrap', placement, ...extra }); // not '…' (gotcha: overflow-ellipsis-default)
const opener = { enabled: true,
  // The band reserves down to its foot; minHeight adds AIR, in whole grid lines.
  minHeight: pt(LEAD * Math.ceil((BAND + AIR - PAGE.top) / (LEAD * PT))),
  slot: { elements: [ // array order is paint order
    { kind: 'box', id: 'band', style: { backgroundColor: col('band') },
      placement: pin('bleed', 'top-left', 0, 0, { height: mm(BAND) }) }, // no width: edge to edge
    { kind: 'image', id: 'rose', resourceId: 'rose', // page 1 is a recto: the fore-edge is right
      placement: pin('page', 'top-right', -PAGE.outer, (BAND - ROSE) / 2, { width: mm(ROSE),
        height: mm(ROSE) }) },
    text('kicker', '{attr.sheet} · {titleText}', LABEL, 9.5, 'sea', pin('page', 'top-left',
      PAGE.inner, 23), { fontWeight: 500, letterSpacing: pt(1.4) }),
    text('title', '{title}', DISPLAY, 56, 'paper', pin('#kicker', 'below', -1, 2),
      { lineHeight: 1 }), // a multiple, never pt() (gotcha: design-lineheight-multiple)
    text('lead', '{attr.lead}', TEXT, 10.5, 'sea', pin('#title', 'below', 1, 3,
      { width: mm(128) }), { italic: true, lineHeight: 1.35 }),
  ] } }; // hook-up: headings.levels[0] = { span: 'page', breakBefore, advancedDesign: opener }
// #endregion

// Running heads: the atlas on the verso, the sheet on the recto, folios on the fore-edge.
const head = (id, content, parity, x, extra) => text(id, content, LABEL, 8.5, 'muted',
  pin('page', x > 0 ? 'top-left' : 'top-right', x, 12), { fontWeight: 500, letterSpacing: pt(1),
    align: x > 0 ? 'left' : 'right', parity, pages: 'body', ...extra });
const folio = { fontFamily: DISPLAY, fontSize: pt(11), fontWeight: 400, letterSpacing: pt(0),
  color: col('band') };
const header = { elements: [head('verso-folio', '{pageNumber}', 'even', PAGE.outer, folio),
  head('verso-title', '{title}', 'even', PAGE.outer + 9),
  head('recto-title', '{chapterTitle}', 'odd', -(PAGE.outer + 9)),
  head('recto-folio', '{pageNumber}', 'odd', -PAGE.outer, folio)] };
const footer = { elements: [{ ...head('drop-folio', '{pageNumber}', 'all', 0, folio),
  pages: 'opener', align: 'center', placement: { anchor: { to: 'container', edge: 'top' },
    offset: { x: mm(0), y: mm(9) } } }] }; // the opener's folio, under the text block
// A styled heading swaps its section's footer: About this sheet sets a hairline and the edition.
const imprint = { id: 'imprint', footer: { elements: [
  { kind: 'rule', id: 'rule', direction: 'horizontal', color: col('rule'), thickness: pt(0.5),
    placement: pin('container', 'top-left', 0, 5, { width: 'fill' }) },
  text('edition', t({ en: 'The Solan Isles, sheet 1 · first edition, 2024 · Kirkwick Harbour '
    + 'Trust', es: 'Las islas Solan, hoja 1 · primera edición, 2024 · Junta del Puerto de '
    + 'Kirkwick' }), LABEL, 8, 'muted', pin('#rule', 'below', 0, 2),
  { letterSpacing: pt(0.6) })] } };

// #region gazetteer: the places numbered north to south, zebra rows filled cell by cell
const CHART = { y0: -5, square: 8 }; // Map 4's grid: 8 km squares from its top-left corner
const PLACES = [ // name, what it is (en, es), island, x and y in km on the sheet, map mark
  ['Skarra', ['lighthouse', 'faro'], 'Skarra', 34.4, 5.4, 'light'],
  ['Hool Stacks', ['sea stacks', 'farallones'], 'Brannay', 22.8, 9],
  ['Kellay', ['gannet colony', 'colonia de alcatraces'], 'Kellay', 5.4, 10.6],
  ['Ward of Brannay', ['summit, 234 m', 'cumbre, 234 m'], 'Brannay', 26.38, 12.04, 'summit'],
  ['Hesta Ness', ['headland', 'cabo'], 'Brannay', 30.1, 15.9],
  ['Tofts', ['hamlet', 'aldea'], 'Brannay', 22.7, 14.9, 'village'],
  ['Kirkwick', ['village and ferry pier', 'pueblo y muelle'], 'Brannay', 28.3, 15, 'village'],
  ['St Brendan’s', ['ruined chapel', 'capilla en ruinas'], 'Brannay', 23.8, 21.6, 'chapel'],
  ['Brannay Sound', ['strait', 'estrecho'], '—', 25.6, 22.7],
  ['Scarfa Ness', ['headland', 'cabo'], 'Orrin', 36.3, 22.3],
  ['Carrick', ['mainland port', 'puerto de tierra firme'], '—', 59.4, 21.2, 'village'],
  ['Orrinsetter', ['hamlet', 'aldea'], 'Orrin', 31.7, 24.8, 'village'],
  ['Housa Stone', ['standing stone', 'menhir'], 'Orrin', 29.4, 25.6, 'stone'],
  ['Leury Sands', ['beach', 'playa'], 'Brannay', 10.9, 25.6],
  ['Holm of Orrin', ['islet', 'islote'], 'Orrin', 37.74, 28.4],
  ['Pollwick', ['bay', 'bahía'], 'Orrin', 32.4, 28.3],
  ['Tang Skerry', ['rock and beacon', 'roca y baliza'], '—', 25.08, 28.88, 'light'],
].map(([name, [en, es], island, x, y, mark]) => ({ name, kind: t({ en, es }), island, x, y, mark }))
  .sort((a, b) => a.y - b.y).map((place, i) => ({ ...place, no: i + 1 }));
const square = ({ x, y }) => 'ABCDEFGH'[Math.floor(x / CHART.square)]
  + (Math.floor((y - CHART.y0) / CHART.square) + 1); // the square the place falls in
function gazetteer() {
  const heads = t({ en: ['No.', 'Place', 'What it is', 'Island', 'Square'],
    es: ['N.º', 'Lugar', 'Qué es', 'Isla', 'Cuadro'] });
  const cells = (row, isHeader = false) => row.map((content) => ({ content, isHeader }));
  let m = { headerRowCount: 1, columnWidths: [8, 34, 42, 18, 12], rows: [cells(heads, true),
    ...PLACES.map((p) => cells([`:chip[${p.no}]{style="no"}`, `**${p.name}**`, p.kind, p.island,
      square(p)]))] };
  for (let row = 0; row < m.rows.length; row++) {
    for (const c of [0, 4]) m = setAlignment(m, { row, col: c }, 'center');
    // A table style has one body fill: every other row is filled here (gotcha: no-zebra).
    if (row % 2 === 0 && row > 0) {
      for (let c = 0; c < 5; c++) m = setCellBackground(m, { row, col: c }, col('sea'));
    }
  }
  return m;
}
// #endregion

const config = () => ({ // a factory: configs are cached by identity (gotcha: config-cache-identity)
  colorPalette, header, footer, captionStyle,
  // Spanish names Tabla; the map type is named in the pen (gotcha: resource-types-locale).
  resourceTypes: [mapType, { ...defaultResourceTypes(LANG)[1], numberingTemplate: '{n}' }],
  page: { width: mm(PAGE.w), height: mm(PAGE.h), dpi: 150, backgroundColor: col('paper'),
    margins: { top: mm(PAGE.top), bottom: mm(PAGE.bottom), left: mm(PAGE.inner),
      right: mm(PAGE.outer), mirror: true } },
  layout: { layoutType: 'double', gutterWidth: mm(6) },
  bodyText: { fontFamily: TEXT, fontSize: pt(9.5), lineHeight: pt(LEAD), color: col('ink'),
    boldColor: col('ink'), italicColor: col('ink'), referenceColor: col('band'), // refs in blue
    textAlign: 'left', firstLineIndent: mm(0), paragraphSpacing: true }, // ragged, a line apart
  headings: { fontFamily: DISPLAY, fontWeight: 400, color: col('band'), levels: [
    // Restated: any headings object drops the H1 break (gotcha: headings-drop-h1-break).
    { level: 1, span: 'page', breakBefore: { enabled: true, parity: 'odd' },
      advancedDesign: opener, marginBottom: pt(0) }, // else a grid line more under the band
    { level: 2, fontSize: pt(14), lineHeight: pt(LEAD * 1.5), marginTop: pt(LEAD / 2),
      marginBottom: pt(0) },
  ] },
  tableStyle: { rules: 'horizontal', borderColor: col('rule'), borderWidth: pt(0.5),
    headerBackground: col('band'), headerColor: col('paper'), headerFontFamily: LABEL,
    headerFontSize: pt(8.5), bodyFontSize: pt(8.8), cellPadding: mm(1.2) },
  chipStyles: [{ id: 'no', background: col('road'), color: col('paper'), bold: true,
    borderWidth: pt(0), borderRadius: em(1), paddingX: em(0.45), fontSize: em(0.92) },
  { id: 'key', backgroundEnabled: false, borderWidth: pt(0), paddingX: pt(0) }],
  headingStyles: [imprint], // ## About this sheet {style="imprint"}
  paragraphStyles: [{ id: 'colophon', fontSize: pt(7.8), lineHeight: pt(10.5),
    color: col('muted') }],
});

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
Markdown样例 · 46行 · content.en.md
title: "The Solan Isles"
---

# The islands and their waters {sheet="Sheet 1" lead="Brannay, Orrin, Kellay and the lighthouse rock of Skarra lie some 20 kilometres off the mainland coast at Carrick. The survey of 1874 drew their coasts; this sheet adds the depths, the roads and a grid for every named place."}

The Solan Isles take their name from the solan goose, the old name for the gannet, which nests by the thousand on the cliffs of Kellay. The group spans 34 kilometres from west to east. Two of its islands are lived on: Brannay, with 612 people at the census of 2021, and Orrin, with 188. :ref{id="relief"} gives the lie of the land in three bands of height, and the roads that join the settlements.

Brannay is a ridge of old gneiss that climbs from Leury Sands in the south-west to the Ward of Brannay, 234 metres above the sea and the highest ground in the group. Orrin, across Brannay Sound, reaches 71 metres and holds most of the farmland. Overleaf, :ref{id="north"} enlarges the north end of Brannay and :ref{id="harbour"} the harbour at Kirkwick, where the Carrick and Orrin ferries share one pier.

## The north end of Brannay

North of the road the island is open hill, heather and bare rock grazed by the sheep of Tofts. A track leaves the road at the plantation above Kirkwick and climbs to the cairn on the Ward, from which Skarra, Kellay and, on a clear day, the hills behind Carrick are all in sight. The north face falls 150 metres to the sea in a kilometre and a half. The Hool Stacks, three pillars of rock off the north-west point, stand where the coast ran before the sea cut it back.

Tofts is the older of the two settlements on Brannay: nine houses, a school closed in 1974 and a burial ground. The road from Kirkwick reaches it in 6 kilometres round the south side of the hill.

The numbers in red discs belong to the gazetteer. The chart of the whole group (:ref{id="chart"}) carries every one of them on a grid of lettered and numbered squares, and :ref{id="gazetteer" style="full"} gives the square that holds each one.

## Kirkwick

Kirkwick stands at the mouth of a voe, a narrow inlet a kilometre long that the sea has cut into the east coast. The village is one street of houses along its west shore, with the kirk that gave it its name on the slope above. The pier runs 330 metres out from the street into the mouth of the voe, and there are 4 metres of water at its head at the lowest tide.

The ferry leaves for Carrick at 07.30 every day, and again at 16.00 from May to September; the crossing of 31 kilometres takes an hour and forty minutes. A launch makes the 8 kilometres to Orrin four times a day. The lifeboat has been stationed here since 1912 and goes down its own slipway inside the voe.

## The waters

Every island stands on a shelf of shallow water :swatch{color="sea"}, less than 20 metres deep, that runs out one or two kilometres from its coast. Beyond it :swatch{color="deep"} the bed lies 20 to 35 metres down, and no sounding on this sheet goes deeper. The tide runs hard through Brannay Sound, at up to 4 knots on spring tides, and small boats keep to the Orrin side at the narrows. Tang Skerry, a low rock south of the Sound, carries an iron beacon with a red light.

The light on Skarra was first lit in 1851 and has worked without keepers since 1998. It shows two white flashes every 15 seconds and can be seen for 18 nautical miles, from the Carrick shore on most nights of the year. The keepers’ cottages below the tower are now a bothy, open to walkers from April to October.

## Place names

Most names on the islands are Norse, from the centuries when they belonged to Norway. An *ay* is an island, as in Brannay and Kellay; a *wick* is a bay, a *ness* a headland, a *setter* a farm and a *holm* an islet. A *skerry* is a rock in the sea and a *stack* a pillar of rock cut off from the cliff. A *ward* is a hill where a watch was kept, and *kirk* is the Scots word for a church. Hool Stacks takes its name from *hóll*, a rounded hill, and Tang Skerry from *þang*, the wrack that grows on it. The survey of 1874 wrote the names as the islanders said them, and some spellings have changed since: its sheet gives Kirkwik and Scarffa Ness.

## Finding a place

The gazetteer lists the seventeen numbered places from north to south. Its last column gives the square of the chart that holds each one: the letter names the column, counted from the west, and the figure the row, counted from the north. Kirkwick, number 6, lies in square D3 with the Ward of Brannay. Carrick, number 8, is in H4, on the mainland shore at the end of the ferry line. The same numbers mark the map of the north end, so Tofts, number 5, can be found at either scale. The grid belongs to this atlas, not to any national survey, and every sheet of the atlas uses the same squares of 8 kilometres.

:::columnbreak

## About this sheet {style="imprint"}

The coasts follow the survey of 1874, checked against air photographs taken in 2019. Heights are in metres above mean sea level. Depths are in metres below the lowest tide; the soundings in the voe of Kirkwick were taken by the harbour trust in May 2024, those of the chart by the survey vessel *Petrel* in 2023. The roads are those open to cars. Tracks, fences and the boundaries of the crofts appear on the six-inch sheets, sold at the harbour office.

:::paragraphs{style="colophon"}
The Solan Isles and their people are invented; the code that sets this sheet draws the land and the sea bed from the seed 1874. Set in Marcellus, Alegreya Sans and Alegreya Sans SC (SIL OFL) · Text and maps: CC BY 4.0.
:::
`; // content.<lang>.md, inlined by the Cookbook
const SEED = 1874; // the survey's year, and the seed every coast and depth is drawn from

// #region art: one seeded height field, drawn as four maps and a compass rose
// Heights and depths come from a few hills and bays warped by value noise; marching squares
// turn each band of RELIEF into closed paths. Numbers are strokes: an SVG drawn as an image
// cannot reach the page's web fonts (gotcha: svg-no-webfonts). No markers or filters.
function mulberry32(seed) { // a seeded PRNG: never Math.random() in a recipe
  return () => {
    seed = (seed + 0x6d2b79f5) | 0;
    let r = Math.imul(seed ^ (seed >>> 15), 1 | seed);
    r = (r + Math.imul(r ^ (r >>> 7), 61 | r)) ^ r;
    return ((r ^ (r >>> 14)) >>> 0) / 4294967296;
  };
}
const rand = mulberry32(SEED);
const LATTICE = Array.from({ length: 64 * 64 }, () => rand() * 2 - 1);
const ease = (t) => t * t * (3 - 2 * t);
function noise(x, y) { // value noise in −1…1 on a 64 × 64 lattice that wraps
  const [i, j] = [Math.floor(x), Math.floor(y)], [u, v] = [ease(x - i), ease(y - j)];
  const at = (a, b) => LATTICE[((b & 63) << 6) | (a & 63)];
  const top = at(i, j) + (at(i + 1, j) - at(i, j)) * u;
  const foot = at(i, j + 1) + (at(i + 1, j + 1) - at(i, j + 1)) * u;
  return top + (foot - top) * v;
}
const fbm = (x, y) => [1, 2, 4, 8].reduce((s, f) => s + noise(f * x, f * y) / (2 * f), 0);
const FLOOR = -46; // m, the sea bed between the islands
const HILLS = [ // x, y, rx, ry (km), turn (°), summit (m); a negative summit carves a bay
  [20.5, 19, 10, 3.3, -38, 110], [26.3, 12.4, 3.8, 3.0, -25, 232], [14.6, 23.6, 3.6, 2.2, -8, 70],
  [11.8, 25.4, 2.4, 1.2, 35, 30], [29.6, 14.8, 1.8, 1.0, 50, 60], [23.5, 20.2, 3.2, 1.5, 60, 60],
  [31, 25.6, 4.6, 2.7, 12, 64], [35.5, 23.4, 2.0, 1.0, -35, 34], [28.2, 27.4, 1.6, 0.9, 25, 30],
  [8, 12, 2.9, 2.0, 12, 132], [6.4, 13.8, 1.3, 0.8, -40, 60], [34.2, 5.2, 1.1, 0.75, 20, 26],
  [23.62, 9.45, 0.2, 0.2, 0, 40], [23.98, 8.98, 0.18, 0.18, 0, 36], [23.4, 9.85, 0.16, 0.16, 0, 30],
  [38.4, 28.4, 0.8, 0.55, 30, 14], [25.1, 29.6, 0.3, 0.22, 0, 4], [74, 22, 16, 40, 8, 260],
  [28.4, 18.4, 1.5, 0.9, 20, -70], [32.6, 27.9, 1.3, 1.0, 0, -60], [17.2, 22.2, 1.0, 0.7, 10, -40],
  [56.6, 21.4, 2.6, 1.6, 10, -80], [55.2, 32.5, 3.2, 1.3, 25, 40],
];
function elevation(x, y) { // [land, sea] in metres at (x, y) km: x east, y south
  const wx = x + 2 * fbm(x / 7, y / 7) + 0.7 * fbm(x / 1.8 + 5, y / 1.8)
    + 0.2 * fbm(x / 0.5, y / 0.5);
  const wy = y + 2 * fbm(x / 7 + 17.3, y / 7 + 9.1) + 0.7 * fbm(x / 1.8, y / 1.8 + 5)
    + 0.2 * fbm(x / 0.5 + 9, y / 0.5);
  let [e, cut, shelf] = [FLOOR, 0, 0];
  for (const [cx, cy, rx, ry, turn, peak] of HILLS) {
    const [c, s, dx, dy] = [Math.cos(turn / 57.3), Math.sin(turn / 57.3), wx - cx, wy - cy];
    const [u, v] = [dx * c + dy * s, dy * c - dx * s];
    const d2 = (u / rx) ** 2 + (v / ry) ** 2;
    if (peak < 0) { cut = Math.max(cut, -peak * Math.exp(-d2)); continue; }
    const k = Math.log((peak - FLOOR) / -FLOOR); // so the coast falls on the ellipse
    e = Math.max(e, FLOOR + (peak - FLOOR) * Math.exp(-k * d2));
    shelf = Math.max(shelf, Math.exp(-((u / (rx + 2.4)) ** 2 + (v / (ry + 2.4)) ** 2)));
  }
  const land = e - cut + 14 * fbm(x / 1.3 + 40, y / 1.3) + 5 * fbm(x / 0.4, y / 0.4 + 60);
  const bed = -40 - 14 * fbm(x / 10 + 3, y / 10) + 38 * shelf + 1.2 * fbm(x / 1.6, y / 1.6 + 30);
  return [land, Math.max(bed, land * 0.6)];
}
const EDGES = { 1: ['B', 'L'], 2: ['R', 'B'], 3: ['R', 'L'], 4: ['T', 'R'], 6: ['T', 'B'],
  7: ['T', 'L'], 8: ['L', 'T'], 9: ['B', 'T'], 11: ['R', 'T'], 12: ['L', 'R'], 13: ['B', 'R'],
  14: ['L', 'B'], 5: ['T', 'L', 'B', 'R', 'T', 'R', 'B', 'L'], // saddles: joined, then apart
  10: ['R', 'T', 'L', 'B', 'L', 'T', 'R', 'B'] };
function contours(grid, nx, ny, level) { // marching squares: closed loops above `level`
  const v = (i, j) => (i && j && i < nx - 1 && j < ny - 1 ? grid[j * nx + i] : -1e9);
  const at = new Map(), next = new Map();
  const edge = (i, j, side) => { // T, B, L or R of cell (i, j), as a key shared by neighbours
    const [a, b, horizontal] = { T: [i, j, 1], B: [i, j + 1, 1], L: [i, j, 0],
      R: [i + 1, j, 0] }[side];
    const key = `${horizontal ? 'h' : 'v'}${a},${b}`;
    if (!at.has(key)) {
      const [p, q] = horizontal ? [v(a, b), v(a + 1, b)] : [v(a, b), v(a, b + 1)];
      const t = (level - p) / (q - p);
      at.set(key, horizontal ? [a + t, b] : [a, b + t]);
    }
    return key;
  };
  for (let j = 0; j < ny - 1; j++) {
    for (let i = 0; i < nx - 1; i++) {
      const corners = [v(i, j), v(i + 1, j), v(i + 1, j + 1), v(i, j + 1)];
      const index = corners.reduce((n, c) => n * 2 + (c > level), 0);
      let sides = EDGES[index];
      if (!sides) continue;
      const high = corners.reduce((a, b) => a + b) / 4 > level; // a saddle: which way it joins
      if (sides.length > 4) sides = high ? sides.slice(0, 4) : sides.slice(4);
      for (let k = 0; k < sides.length; k += 2) {
        next.set(edge(i, j, sides[k]), edge(i, j, sides[k + 1]));
      }
    }
  }
  const loops = [];
  for (const start of [...next.keys()]) {
    const loop = [];
    for (let k = start; next.has(k);) {
      loop.push(at.get(k));
      const n = next.get(k);
      next.delete(k);
      k = n;
    }
    if (loop.length > 5) loops.push(loop);
  }
  return loops;
}
const chaikin = (loop) => loop.flatMap((p, i) => {
  const q = loop[(i + 1) % loop.length];
  return [[0.75 * p[0] + 0.25 * q[0], 0.75 * p[1] + 0.25 * q[1]],
    [0.25 * p[0] + 0.75 * q[0], 0.25 * p[1] + 0.75 * q[1]]];
});
const r1 = (n) => Math.round(n * 10) / 10;
function sheet(win, w, h, cell = 0.6) { // the window [x0, x1] × [y0, y1] km drawn w × h mm
  const [nx, ny] = [Math.ceil(w / cell) + 1, Math.ceil(h / cell) + 1];
  const [land, sea] = [new Float32Array(nx * ny), new Float32Array(nx * ny)];
  for (let j = 0; j < ny; j++) {
    for (let i = 0; i < nx; i++) {
      [land[j * nx + i], sea[j * nx + i]] = elevation(win.x0 + i * (win.x1 - win.x0) / (nx - 1),
        win.y0 + j * (win.y1 - win.y0) / (ny - 1));
    }
  }
  const k = w / (win.x1 - win.x0); // mm per km
  const X = (x) => r1((x - win.x0) * k), Y = (y) => r1((y - win.y0) * k);
  const loops = (level, field) => contours(field, nx, ny, level).map((loop) => {
    const p = chaikin(chaikin(loop));
    return `M${p.map(([i, j]) => `${r1(i * w / (nx - 1))} ${r1(j * h / (ny - 1))}`).join('L')}Z`;
  }).join('');
  return { X, Y, k, w, h, land: (level) => loops(level, land), sea: (level) => loops(level, sea) };
}
const fill = (d, id, more = '') => `<path d="${d}" fill="${palette[id]}" fill-rule="evenodd"`
  + `${more}/>`;
const line = (d, id, width, more = '') => `<path d="${d}" fill="none" stroke="${palette[id]}" `
  + `stroke-width="${width}" stroke-linecap="round" stroke-linejoin="round"${more}/>`;
const poly = (s, pts) => `M${pts.map(([x, y]) => `${s.X(x)} ${s.Y(y)}`).join('L')}`;
const nearLine = (x, y, pts, d) => pts.slice(1).some(([bx, by], i) => { // within d of the line
  const [ax, ay] = pts[i], [dx, dy] = [bx - ax, by - ay];
  const t = Math.max(0, Math.min(1, ((x - ax) * dx + (y - ay) * dy) / (dx * dx + dy * dy)));
  return Math.hypot(ax + t * dx - x, ay + t * dy - y) < d;
});

// A stroke font for numbers and grid letters, 4 × 6 units with the baseline at 6.
const GLYPHS = {
  0: 'M2 0C.6 0 0 1.4 0 3s.6 3 2 3 2-1.4 2-3-.6-3-2-3Z', 1: 'M.9 1.2 2.4 0v6',
  2: 'M.2 1.2C.6.4 1.3 0 2 0c1.2 0 2 .8 2 1.8C4 3.2 2.8 3.9 0 6h4.2',
  3: 'M.3.5C.8.2 1.4 0 2 0c1.2 0 1.9.7 1.9 1.6S3.1 3 2 3c1.3 0 2.1.7 2.1 1.6S3.3 6 2 6'
    + 'C1.3 6 .6 5.8.1 5.4',
  4: 'M3 6V0L0 4.2h4.2',
  5: 'M3.8 0h-3L.4 2.8c.5-.3 1-.4 1.6-.4 1.3 0 2.1.8 2.1 1.8C4.1 5.3 3.2 6 2 6 1.3 6 .6 5.8.1 5.4',
  6: 'M3.6.4C3.2.1 2.7 0 2.2 0 .9 0 .1 1.3.1 3.4.1 5.1.8 6 2.1 6c1.2 0 2-.8 2-1.9S3.3 2.3 2.2 2.3'
    + 'C1.1 2.3.3 3 .1 3.8',
  7: 'M0 0h4L1.6 6',
  8: 'M2 3C.9 3 .3 2.4.3 1.5S.9 0 2 0s1.7.6 1.7 1.5S3.1 3 2 3C.8 3 0 3.7 0 4.5S.8 6 2 6s2-.7 2-1.5'
    + 'S3.2 3 2 3Z',
  9: 'M.4 5.6c.4.3.9.4 1.4.4 1.3 0 2.1-1.3 2.1-3.4C3.9.9 3.2 0 1.9 0 .7 0-.1.8-.1 1.9'
    + 'S.7 3.7 1.8 3.7'
    + 'c1.1 0 1.9-.7 2.1-1.5',
  A: 'M0 6 2 0l2 6M.7 4h2.6',
  B: 'M0 3h2.2c1.1 0 1.8.7 1.8 1.5S3.3 6 2.2 6H0V0h2c1 0 1.6.6 1.6 1.5S3 3 2 3',
  C: 'M4 .9C3.5.3 2.8 0 2.1 0 .8 0 0 1.3 0 3s.8 3 2.1 3c.7 0 1.4-.3 1.9-.9',
  D: 'M0 0v6h1.8C3.2 6 4 4.8 4 3S3.2 0 1.8 0Z', E: 'M4 0H0v6h4M0 3h3', F: 'M4 0H0v6M0 3h3',
  G: 'M4 .9C3.5.3 2.8 0 2.1 0 .8 0 0 1.3 0 3s.8 3 2.1 3C3.2 6 4 5.4 4 4v-.7H2.4',
  H: 'M0 0v6m4-6v6M0 3h4',
  N: 'M0 6V0l4 6V0', k: 'M0 0v6m3.4-3.6L0 5m1.3-1 2.5 2',
  m: 'M0 6V2.4m0 .9c.3-.6.8-.9 1.3-.9s.9.4.9 1.1V6m0-2.5c0-.7.5-1.1 1.1-1.1s1.1.4 1.1 1.2V6',
};
const advance = (c) => (c === 'm' ? 5.6 : 5.2);
const labelWidth = (s, size) => ([...String(s)].reduce((a, c) => a + advance(c), 0) - 1.2)
  * size / 6;
function label(s, x, y, size, id, weight = 0.14) { // `s` in strokes, `size` mm tall, centred
  const k = size / 6;
  let pen = x - labelWidth(s, size) / 2;
  return [...String(s)].map((c) => {
    const at = `translate(${r1(pen)} ${r1(y - size / 2)}) scale(${k.toFixed(3)})`;
    pen += advance(c) * k;
    return `<path d="${GLYPHS[c]}" transform="${at}" fill="none" stroke="${palette[id]}" `
      + `stroke-width="${r1(6 * weight)}" stroke-linecap="round" stroke-linejoin="round"/>`;
  }).join('');
}
function disc(n, x, y, size) { // a place number, white on a red pill, as in the gazetteer
  const w = labelWidth(String(n), size) + size * 0.9;
  return `<rect x="${r1(x - w / 2)}" y="${r1(y - size * 0.95)}" width="${r1(w)}" `
    + `height="${r1(size * 1.9)}" rx="${r1(size * 0.95)}" fill="${palette.road}" `
    + `stroke="${palette.paper}" stroke-width="0.3"/>`
    + label(n, x, y, size, 'paper', 0.16);
}
function scaleBar(s, x, y, km, step) { // ink and paper blocks, a figure every step
  const [unit, f] = km < 1 ? ['m', 1000] : ['km', 1];
  let out = '';
  for (let d = 0; d < km - 1e-9; d += step / 2) {
    out += `<rect x="${r1(x + d * s.k)}" y="${y}" width="${r1(step / 2 * s.k)}" height="1.2" `
      + `fill="${palette[Math.round(d / (step / 2)) % 2 ? 'paper' : 'ink']}" `
      + `stroke="${palette.ink}" stroke-width="0.2"/>`;
  }
  for (let d = 0; d <= km + 1e-9; d += step) {
    out += label(Math.round(d * f), x + d * s.k, y - 2.2, 2, 'ink');
  }
  return out + label(unit, x + km * s.k + 4 + (unit === 'km') * 1, y + 0.6, 2, 'ink');
}
const north = (x, y, size) => [1, -1].map((d) => `<path d="M${x} ${y}l${d * size * 0.35} ${size}`
  + `l${-d * size * 0.35} ${-size * 0.25}Z" fill="${palette[d > 0 ? 'ink' : 'paper']}" `
  + `stroke="${palette.ink}" stroke-width="${d > 0 ? 0 : 0.2}"/>`).join('')
  + label('N', x, y - 2.6, 2.4, 'ink'); // a north arrow, half ink and half paper

// What sits on the land, in km on the same field; the places' marks come from PLACES.
const ROADS = [ // Kirkwick to Leury along the ridge, Kirkwick to Tofts, the chapel, Orrin
  [[28.3, 15], [28.1, 15.5], [27.6, 16.1], [26.6, 16.6], [25.4, 17.5], [24.4, 18.8], [23.2, 19.8],
    [22, 20.8], [20.6, 21.6], [19, 22.2], [17.4, 22.9], [15.6, 23.6], [13.8, 24.4], [12.2, 25],
    [11.2, 25.4]],
  [[28.3, 15], [28.1, 14.7], [27.4, 14.3], [26.4, 14.3], [25.2, 14.5], [24.2, 14.6], [23.3, 14.7],
    [22.7, 14.9]],
  [[24.4, 18.8], [24, 20.4], [23.8, 21.6]],
  [[30.2, 23.1], [30.8, 23.8], [31.4, 24.4], [31.7, 24.8], [31.9, 25.6], [32.1, 26.6]],
];
const PIER = [28.75, 15.15]; // the head of Kirkwick pier, where both ferries berth
const FERRIES = [[PIER, [29.1, 15.8], [29.6, 17.6], [30.1, 20.2], [30.2, 22.9]], // to Orrin
  [PIER, [29.1, 15.8], [29.8, 16.9], [34, 18.4], [44, 19.6], [52, 20.5], [58.6, 21.2]]]; // Carrick
const WOODS = [[26.6, 15.4, 0.8, 0.4, -30], [30.6, 25.6, 0.7, 0.4, 10], [18.6, 21, 0.9, 0.35, -25]];
const smoothLine = (pts) => [pts[0], ...chaikin(pts).slice(1, -2), pts.at(-1)]; // an open line
function woods(s) { // a plantation outline wobbled by the noise
  return WOODS.map(([cx, cy, rx, ry, turn]) => {
    const [c, n] = [Math.cos(turn / 57.3), Math.sin(turn / 57.3)];
    const pts = Array.from({ length: 36 }, (_, i) => {
      const a = i / 36 * 2 * Math.PI;
      const f = 1 + 0.3 * noise(cx * 3 + Math.cos(a) * 2, cy * 3 + Math.sin(a) * 2);
      const [u, v] = [rx * f * Math.cos(a), ry * f * Math.sin(a)];
      return [cx + u * c - v * n, cy + u * n + v * c];
    });
    return fill(`${poly(s, pts)}Z`, 'forest', ' fill-opacity=".85"');
  }).join('');
}
const MARKS = { // what each kind of place looks like, centred on (x, y) mm
  village: (x, y) => `<circle cx="${x}" cy="${y}" r="0.9" fill="${palette.ink}"/>`,
  light: (x, y) => star(x, y, 1.5),
  summit: (x, y) => `<path d="M${x} ${r1(y - 1)}l1 1.7h-2Z" fill="${palette.ink}"/>`,
  chapel: (x, y) => line(`M${x} ${r1(y - 1.1)}v2.2M${r1(x - 0.7)} ${r1(y - 0.4)}h1.4`, 'ink', 0.4),
  stone: (x, y) => `<rect x="${r1(x - 0.35)}" y="${r1(y - 1)}" width="0.7" height="2" `
    + `fill="${palette.ink}"/>`,
};
function relief(s, { step = 50, roads = true } = {}) { // the layers every map shares
  let out = `<rect width="${s.w}" height="${s.h}" fill="${palette.deep}"/>`;
  const [under, ...above] = RELIEF.filter((band) => band.from !== undefined);
  out += fill(s.sea(under.from), under.id);
  for (const depth of [-16, -8, -3]) out += line(s.land(depth), 'deep', 0.16); // water-lines
  for (const band of above) out += fill(s.land(band.from), band.id);
  for (let m = step; m < 240; m += step) { // contour lines, except where a tint already changes
    if (!RELIEF.some((band) => band.from === m)) {
      out += line(s.land(m), 'muted', 0.12, ' opacity=".45"');
    }
  }
  out += woods(s) + line(s.land(0), 'band', 0.3);
  if (!roads) return out;
  for (const f of FERRIES) out += line(poly(s, f), 'band', 0.35, ' stroke-dasharray="1.6 1.2"');
  for (const r of ROADS.map(smoothLine)) {
    out += line(poly(s, r), 'paper', 1.1) + line(poly(s, r), 'road', 0.55); // a cased road
  }
  for (const p of PLACES) if (p.mark) out += MARKS[p.mark](s.X(p.x), s.Y(p.y));
  return out;
}
const star = (x, y, r) => `<path d="${Array.from({ length: 8 }, (_, i) => {
  const a = i * Math.PI / 4, q = i % 2 ? 0.45 : 1;
  return `${i ? 'L' : 'M'}${r1(x + Math.sin(a) * r * q)} ${r1(y - Math.cos(a) * r * q)}`;
}).join('')}Z" fill="${palette.road}" stroke="${palette.paper}" stroke-width="0.2"/>`;
const svg = (w, h, body) => `<svg xmlns="http://www.w3.org/2000/svg" width="${w * 10}" `
  + `height="${h * 10}" viewBox="0 0 ${w} ${h}">${body}</svg>`; // 10 px to the mm

// The four maps and the rose, at the sizes the resources declare (MAP, in mm).
const frame = (w, h) => `<rect x=".15" y=".15" width="${r1(w - 0.3)}" height="${r1(h - 0.3)}" `
  + `fill="none" stroke="${palette.ink}" stroke-width="0.3"/>`;
const discs = (s, list) => list.map((p) => disc(p.no, s.X(p.x) + (p.mark ? 3 : 0), // beside a mark
  s.Y(p.y) - (p.mark ? 2.4 : 0), 1.9)).join('');
const inside = (s, p) => s.X(p.x) > 3 && s.X(p.x) < s.w - 3 && s.Y(p.y) > 3 && s.Y(p.y) < s.h - 3;
function reliefMap([w, h]) { // Map 1: the whole group, its bands of height and its roads
  const s = sheet({ x0: -1.5, x1: 44.5, y0: 0.5, y1: 0.5 + h * 46 / w }, w, h);
  return svg(w, h, relief(s) + scaleBar(s, 8, h - 6, 10, 5) + north(w - 9, 7, 7) + frame(w, h));
}
function northMap([w, h]) { // Map 2: the north end of Brannay, contours every 25 m, numbered
  const s = sheet({ x0: 20.4, x1: 31.8, y0: 7.4, y1: 7.4 + h * 11.4 / w }, w, h, 0.35);
  const top = PLACES.find((p) => p.mark === 'summit'); // its spot height, as the text gives it
  return svg(w, h, relief(s, { step: 25 }) + discs(s, PLACES.filter((p) => inside(s, p)))
    + label(Math.round(elevation(top.x, top.y)[0]), s.X(top.x), s.Y(top.y) + 2.6, 1.8, 'ink')
    + scaleBar(s, 6, h - 5, 2, 1) + north(w - 7, 6, 5.5) + frame(w, h));
}
function harbourMap([w, h]) { // Map 3: Kirkwick, its pier and the soundings of the voe
  const s = sheet({ x0: 27.62, x1: 30.42, y0: 13.95, y1: 13.95 + h * 2.8 / w }, w, h, 0.4);
  const rand = mulberry32(SEED + 3);
  let out = relief(s, { step: 25, roads: false });
  const key = [[28.64, 15.25], [28.74, 14.6], [28.28, 15.02], [28.16, 15.37], [28.24, 14.44]];
  const kirk = `<rect x="-1.4" y="-.8" width="2.8" height="1.6" fill="${palette.ink}"/>`
    + line('M1.4 0h1.6m-.8-.8v1.6', 'ink', 0.35); // nave and a cross at its east end
  out += `<g transform="translate(${s.X(28.34)} ${s.Y(14.52)}) rotate(-20)">${kirk}</g>`;
  const clear = (x, y) => key.every(([kx, ky]) => Math.hypot(s.X(kx) - x, s.Y(ky) - y) > 4)
    && !(x < 34 && y > h - 13) && !(x > w - 13 && y < 15); // off the key, scale and arrow
  for (let y = 14.08; y < 16.5; y += 0.2) { // soundings: metres below the lowest tide
    for (let x = 27.7 + (Math.round(y / 0.2) % 2) * 0.1; x < 30.4; x += 0.2) {
      const depth = -elevation(x, y)[1];
      if (depth > 1.5 && elevation(x, y)[0] < -1.5 && clear(s.X(x), s.Y(y))
        && !nearLine(x, y, FERRIES[1], 0.06)) {
        out += label(Math.round(depth), s.X(x), s.Y(y), 1.5, 'band', 0.11);
      }
    }
  }
  const street = [[28.62, 14.3], [28.55, 14.6], [28.47, 14.9], [28.4, 15.1], [28.2, 15.45],
    [27.95, 15.75], [27.62, 15.98]];
  const up = [[28.47, 14.9], [28.25, 14.75], [28.05, 14.55], [27.62, 14.35]];
  out += line(poly(s, street), 'paper', 1.6) + line(poly(s, up), 'paper', 1.6)
    + line(poly(s, street), 'road', 0.9) + line(poly(s, up), 'road', 0.9);
  for (const [a, b, side] of [[0, 3, 1], [3, 5, 1], [0, 3, -1]]) { // houses along the street
    for (let t = 0.04; t < 0.96; t += 0.08 + rand() * 0.05) {
      const [p, q] = [street[a], street[b]];
      const [x, y] = [s.X(p[0] + (q[0] - p[0]) * t), s.Y(p[1] + (q[1] - p[1]) * t)];
      const turn = Math.atan2(s.Y(q[1]) - s.Y(p[1]), s.X(q[0]) - s.X(p[0])) * 57.3;
      out += `<rect x="-.7" y="${side > 0 ? -2.7 : 1.2}" width="${r1(1.1 + rand() * 0.6)}" `
        + 'height="1.4" '
        + `transform="translate(${r1(x)} ${r1(y)}) rotate(${r1(turn)})" fill="${palette.hill2}" `
        + `stroke="${palette.ink}" stroke-width="0.2"/>`;
    }
  }
  const pier = [[28.43, 15.07], PIER]; // 330 m of pier across the mouth of the voe
  out += line(poly(s, pier), 'ink', 2.2) + line(poly(s, pier), 'paper', 1.6)
    + line(poly(s, [[28.55, 14.66], [28.67, 14.71]]), 'ink', 1.2) // the lifeboat slipway
    + line(poly(s, [[28.55, 14.66], [28.67, 14.71]]), 'paper', 0.7)
    + line(poly(s, FERRIES[1].slice(0, 3)), 'band', 0.35, ' stroke-dasharray="1.6 1.2"')
    + star(s.X(PIER[0]), s.Y(PIER[1]), 1.3);
  out += key.map(([x, y], i) => `<circle cx="${s.X(x)}" cy="${s.Y(y)}" r="1.7" `
    + `fill="${palette.paper}" stroke="${palette.ink}" stroke-width="0.25"/>`
    + label(i + 1, s.X(x), s.Y(y), 1.8, 'ink')).join('');
  return svg(w, h, out + scaleBar(s, 6, h - 5, 0.5, 0.25) + north(w - 7, 6, 5.5) + frame(w, h));
}

function chartMap([w, h], b = 5) { // Map 4: the whole sheet, the approaches and the grid
  const [iw, ih] = [w - 2 * b, h - 2 * b];
  const s = sheet({ x0: 0, x1: 64, y0: CHART.y0, y1: CHART.y0 + ih * 64 / iw }, iw, ih, 0.7);
  const q = CHART.square * s.k; // a square, in mm
  let grid = '', border = ''; // lines inside the frame; letters and figures in the margin round it
  for (let c = 0; c < 8; c++) {
    for (const y of [b / 2, h - b / 2]) {
      border += label('ABCDEFGH'[c], b + (c + 0.5) * q, y, 2.6, 'ink');
    }
    if (c) grid += line(`M${r1(c * q)} 0V${ih}`, 'band', 0.2, ' opacity=".55"');
  }
  for (let r = 0; r * q < ih; r++) { // the last row is cut by the frame
    const mid = b + (r * q + Math.min(ih, (r + 1) * q)) / 2;
    for (const x of [b / 2, w - b / 2]) border += label(r + 1, x, mid, 2.6, 'ink');
    if (r) grid += line(`M0 ${r1(r * q)}H${iw}`, 'band', 0.2, ' opacity=".55"');
  }
  let soundings = ''; // depths in the open sea, clear of the coast, the places and the ferries
  const near = (x, y, d) => PLACES.some((p) => Math.hypot(p.x - x, p.y - y) < d)
    || FERRIES.some((f) => nearLine(x, y, f, d / 2))
    || [0, 1, 2, 3, 4, 5, 6, 7].some((i) => elevation(x + Math.cos(i * Math.PI / 4), // or land
      y + Math.sin(i * Math.PI / 4))[0] > 0); // within 1 km, so no figure reaches the coast
  for (let y = CHART.y0 + 2; y < CHART.y0 + ih / s.k; y += 3.4) {
    for (let x = 2 + (Math.round(y / 3.4) % 2) * 1.7; x < 64; x += 3.4) {
      const [land, sea] = elevation(x, y);
      const [X, Y] = [s.X(x), s.Y(y)]; // inside the frame, off the scale bar and the arrow
      const clear = X > 3 && X < iw - 3 && Y > 3 && Y < ih - 3 && !(X < 60 && Y > ih - 30);
      if (land < -12 && clear && !near(x, y, 2.4)) {
        soundings += label(Math.round(-sea), X, Y, 1.7, 'band', 0.11);
      }
    }
  }
  const body = relief(s) + soundings + grid + discs(s, PLACES) + scaleBar(s, 8, ih - 6, 10, 5)
    + north(14, ih - 24, 7);
  return svg(w, h, `<rect width="${w}" height="${h}" fill="${palette.paper}"/>${border}`
    + `<g transform="translate(${b} ${b})">${body}${frame(iw, ih)}</g>`);
}
function rose(size) { // the compass rose on the opener's band, in the band's own blues
  const c = size / 2;
  const at = (a, r) => `${r1(c + Math.sin(a) * r)} ${r1(c - Math.cos(a) * r)}`; // polar, from c
  let out = [0.42, 0.37, 0.19].map((f, i) => `<circle cx="${c}" cy="${c}" r="${r1(size * f)}" `
    + `fill="none" stroke="${palette.deep}" stroke-width="${i ? 0.25 : 0.5}"/>`).join('');
  out += line(Array.from({ length: 64 }, (_, i) => { // ticks, longer every fourth
    const a = i * Math.PI / 32;
    return `M${at(a, size * 0.37)}L${at(a, size * (i % 4 ? 0.395 : 0.42))}`;
  }).join(''), 'deep', 0.2);
  for (const [n, long, w] of [[8, 0.32, 0.05], [4, 0.42, 0.07]]) { // half-winds, then N E S W
    for (let i = 0; i < n; i++) {
      const a = (i + (n === 8 ? 0.5 : 0)) * 2 * Math.PI / n;
      for (const d of [1, -1]) { // each point in two halves, one light and one dark
        out += `<path d="M${c} ${c}L${at(a + d * Math.PI / 2, size * w)}L${at(a, size * long)}Z" `
          + `fill="${palette[d > 0 ? 'sea' : 'deep']}"/>`;
      }
    }
  }
  return svg(size, size, out + label('N', c, 1.9, 3, 'sea', 0.12));
}
// #endregion

// #region resources: the four maps and the gazetteer, each cited in the text with :ref
// A plan's key: a bare chip keeps each number on the line of its name, and the dot after it.
const key = (names) => names.map((name, i) => `:chip[${i + 1} ${name}${names[i + 1] ? ' ·' : ''}]`
  + '{style="key"}').join(' ');
const TEXTS = t({ // caption, the key under the drawing, and the alt text of each map
  en: {
    relief: ['The islands: relief and roads', `${legend} · roads in red, ferries dashed`,
      'Relief map of Brannay, Orrin, Kellay and Skarra in sand and ochre on blue water, with '
      + 'red roads.'],
    north: ['The north end of Brannay', 'Contour interval 25 metres; heights in metres above the '
      + 'sea. The red discs number the places of the gazetteer.', 'The Ward of Brannay, 234 m, in '
      + 'contours, with the Hool Stacks off its north-west point and the road round it to Tofts.'],
    harbour: ['Kirkwick harbour', 'Soundings in metres at the lowest tide. '
      + key(['ferry pier and light', 'lifeboat station', 'harbour office', 'fish store', 'kirk']),
      'Plan of Kirkwick: one street of houses on a narrow inlet, a pier into its mouth, depths '
      + 'from 2 to 15 m.'],
    chart: ['The islands and their approaches, with the gazetteer’s grid', 'Squares of 8 '
      + 'kilometres, lettered west to east and numbered north to south.', 'Chart of the group '
      + 'and the mainland coast on a lettered grid, with the seventeen places in red discs.'],
    table: ['Gazetteer of the numbered places', 'Squares are those of :ref{id="chart"}.'],
  },
  es: {
    relief: ['Las islas: relieve y carreteras', `${legend} · carreteras en rojo, `
      + 'transbordadores a trazos', 'Relieve de Brannay, Orrin, Kellay y Skarra en tintas de '
      + 'arena y ocre sobre agua azul, con las carreteras en rojo.'],
    north: ['El extremo norte de Brannay', 'Equidistancia de las curvas: 25 metros; alturas en '
      + 'metros sobre el mar. Los discos rojos numeran los lugares del nomenclátor.', 'El Ward '
      + 'of Brannay, de 234 m, en curvas de nivel, con los Hool Stacks frente a su punta noroeste '
      + 'y la carretera de Tofts.'],
    harbour: ['El puerto de Kirkwick', 'Sondas en metros con la marea más baja. '
      + key(['muelle y luz', 'estación de salvamento', 'oficina del puerto', 'almacén de pescado',
        'iglesia']), 'Plano de Kirkwick: una calle de casas junto a una ensenada estrecha, un '
      + 'muelle en su boca y fondos de 2 a 15 m.'],
    chart: ['Las islas y sus accesos, con la cuadrícula del nomenclátor', 'Cuadros de 8 '
      + 'kilómetros, con letras de oeste a este y números de norte a sur.', 'Carta del grupo y de '
      + 'la costa de tierra firme en cuadros, con los diecisiete lugares en discos rojos.'],
    table: ['Nomenclátor de los lugares numerados',
      'Los cuadros son los del :ref{id="chart" case="lower"}.'],
  },
});
const svgResource = (id, [w, h], more) => ({ id, typeId: 'map', kind: 'svg', createdAt: 0,
  updatedAt: 0, svg: { fileId: `${id}.svg`, width: w * 10, height: h * 10 }, ...more });
const resources = [
  ...Object.keys(MAP).map((id) => svgResource(id, MAP[id], { placement: PLACEMENT[id],
    caption: TEXTS[id][0], note: TEXTS[id][1], altText: TEXTS[id][2] })),
  svgResource('rose', [ROSE, ROSE], { altText: t({ en: 'Compass rose',
    es: 'Rosa de los vientos' }) }),
  { id: 'gazetteer', typeId: 'table', kind: 'table', createdAt: 0, updatedAt: 0,
    caption: TEXTS.table[0], note: TEXTS.table[1], placement: { position: 'top', span: 'page' },
    table: { model: gazetteer() } },
];
const drawings = { relief: reliefMap, north: northMap, harbour: harbourMap, chart: chartMap };
for (const [id, draw] of Object.entries(drawings)) await loadSvg(`${id}.svg`, draw(MAP[id]));
await loadSvg('rose.svg', rose(ROSE)); // drawn by the opener, never cited, so never numbered
// #endregion

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = { // every face the layout uses, loaded before the build (gotcha: fonts-first)
  'Alegreya Sans': ['400', '400i', '700'], // text, lead, place names and chips
  'Alegreya Sans SC': ['400', '500', '700'], // captions, heads, kicker, table head, labels
  Marcellus: ['400'], // the atlas's name, section heads and folios: one weight, no italic
};

// ─── 4 · Build & show ───────────────────────────────────────────────────────
await loadFonts(FONTS, markdown);
const doc = await buildWithFonts(() => buildDocument({ markdown, resources }, config()), markdown);
showPages(doc, { title: t({ en: 'The Solan Isles · Sheet 1', es: 'Las islas Solan · Hoja 1' }) });

工具包 · core, fonts, viewer, images：每道食谱都相同 · 270行
// ─── Kit ── helpers shared by every Cookbook recipe · postext.dev/cookbook ─────

// ─── Kit · core v1 ── the same in every recipe · postext.dev/cookbook ─────────
function mm(value) { return { value, unit: 'mm' }; }
function pt(value) { return { value, unit: 'pt' }; }
function em(value) { return { value, unit: 'em' }; }
/** The sample language's string: t({ en: 'Figure', es: 'Figura' }). */
function t(strings) { return strings[LANG] ?? Object.values(strings)[0]; }
/** A file in this recipe's assets folder, served from the Postext repo by jsDelivr. */
function asset(file) { return `https://cdn.jsdelivr.net/gh/drnachio/postext@main/cookbook/${RECIPE}/assets/${file}`; }

// ─── Kit · fonts v1 ── the same in every recipe · postext.dev/cookbook ────────
// Postext measures text with the faces the browser has loaded, and caches the
// widths, so every face must be ready before the first build. Faces come from
// Fontsource: the same static files the PDF embeds, so screen and PDF agree.

/** faces = { 'Family Name': ['400', '400i', '700'] }. `text` is the sample:
 *  letters beyond Latin-1 (č, ł, ő…) also load the latin-ext files. With
 *  `optional`, a face Fontsource does not ship is skipped instead of failing.
 *  Resolves to the number of faces added. */
async function loadFonts(faces, text = '', { optional = false } = {}) {
  kitStatus('Loading fonts…');
  const ranges = {
    latin: 'U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,'
      + 'U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD',
    'latin-ext': 'U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,'
      + 'U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF',
  };
  const subsets = /[Ā-˿Ḁ-ỿ]/.test(text) ? ['latin', 'latin-ext'] : ['latin'];
  const jobs = [];
  let added = 0;
  for (const [family, specs] of Object.entries(faces)) {
    const id = fontsourceId(family);
    const meta = optional ? await fontsourceMeta(family) : null;
    for (const spec of new Set(specs)) {
      const weight = parseInt(spec, 10);
      const style = spec.endsWith('i') ? 'italic' : 'normal';
      if (hasFace(family, weight, style)) continue;
      if (optional && !(meta?.weights.includes(weight) && meta.styles.includes(style))) continue;
      for (const subset of subsets) {
        const url = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-${subset}-${weight}-${style}.woff2`;
        const face = new FontFace(family, `url(${url}) format('woff2')`,
          { weight: String(weight), style, unicodeRange: ranges[subset] });
        jobs.push(face.load().then((ready) => { document.fonts.add(ready); added++; }, () => {
          if (subset === 'latin' && !optional) throw new Error(`Fontsource has no ${family} ${weight} ${style}`);
        }));
      }
    }
  }
  await Promise.all(jobs).catch((error) => { kitFail(error); throw error; });
  return added;
}

/** Runs `build` (a buildDocument or buildBundle call) and checks the faces
 *  the pages use. A regular face missing from FONTS is loaded with a warning;
 *  bold and italic variants are loaded when the family ships them. Then the
 *  measurement caches are cleared and the build runs again. */
async function buildWithFonts(build, text = '') {
  const tried = new Set();
  for (let round = 0; round < 3; round++) {
    kitStatus('Laying out…');
    await new Promise(requestAnimationFrame);          // let the status paint first
    const result = await Promise.resolve().then(build).catch((error) => { kitFail(error); throw error; });
    const wanted = { base: {}, variants: {} };
    for (const { font, base } of [result].flat().flatMap(fontStringsOf)) {
      const { family, weight, style } = parseFont(font);
      const key = `${family}|${weight}|${style}`;
      if (tried.has(key) || hasFace(family, weight, style)) continue;
      tried.add(key);
      (wanted[base ? 'base' : 'variants'][family] ??= []).push(`${weight}${style === 'italic' ? 'i' : ''}`);
    }
    if (Object.keys(wanted.base).length) {
      console.warn(`[cookbook] FONTS does not list ${JSON.stringify(wanted.base)}: loading them.`);
    }
    const added = await loadFonts(wanted.base, text) + await loadFonts(wanted.variants, text, { optional: true });
    if (added === 0) return result;
    clearMeasurementCache();
  }
  throw new Error('The fonts did not settle after three builds.');
}

/** Every font string of the layout. `base` marks a block's own face; its
 *  bold, italic and bold-italic variants are listed whether or not used. */
function fontStringsOf(doc) {
  const found = new Map();
  const walk = (node) => {
    if (!node || typeof node !== 'object') return;
    if (Array.isArray(node)) { node.forEach(walk); return; }
    for (const [key, value] of Object.entries(node)) {
      if (typeof value === 'string' && /fontString$/i.test(key)) {
        found.set(value, found.get(value) || key === 'fontString');
      } else if (value && typeof value === 'object') walk(value);
    }
  };
  walk(doc.pages);
  walk(doc.blocks);
  return [...found].map(([font, base]) => ({ font, base }));
}

/** '700 37.5px Open Sans' / 'italic 400 13px "Source Serif 4"' → { family, weight, style }.
 *  A string with no weight ('95.8px Young Serif', from a design text) is 400. */
function parseFont(font) {
  const m = /^(?:(italic|oblique)\s+)?(?:small-caps\s+)?(?:(\d+|bold|normal)\s+)?[\d.]+px\s+(.+)$/.exec(font.trim());
  if (!m) throw new Error(`Unexpected font string: ${font}`);
  const weight = m[2] === 'bold' ? 700 : !m[2] || m[2] === 'normal' ? 400 : Number(m[2]);
  return { family: m[3].replace(/^["']|["']$/g, ''), weight, style: m[1] ? 'italic' : 'normal' };
}

/** True when a loaded FontFace covers exactly this family, weight and style
 *  (document.fonts.check() is also true for families nobody declared). */
function hasFace(family, weight, style) {
  for (const face of document.fonts) {
    if (face.status !== 'loaded' || face.style !== style) continue;
    if (face.family.replace(/^["']|["']$/g, '') !== family) continue;
    const [low, high = low] = face.weight.split(' ').map(Number);
    if (weight >= low && weight <= high) return true;
  }
  return false;
}

/** Fontsource's id for a family: 'Source Serif 4' → 'source-serif-4'. */
function fontsourceId(family) { return family.toLowerCase().replace(/\s+/g, '-'); }

/** The weights and styles a family ships ({ weights: [400, 700], styles: ['normal', 'italic'] }), or null. */
function fontsourceMeta(family) {
  fontsourceMeta.cache ??= new Map();
  const id = fontsourceId(family);
  if (!fontsourceMeta.cache.has(id)) {
    fontsourceMeta.cache.set(id, fetch(`https://api.fontsource.org/v1/fonts/${id}`)
      .then((res) => (res.ok ? res.json() : null), () => null));
  }
  return fontsourceMeta.cache.get(id);
}

// ─── Kit · viewer v1 ── the same in every recipe · postext.dev/cookbook ───────
/** Shows the pages as facing spreads on a dark desk: the first page is a
 *  recto on its own, then verso | recto pairs, as in a bound book. Pages
 *  are painted when they scroll near the screen. */
function showPages(docs, { title, width = 460 } = {}) {
  const root = viewer(title);
  const pages = [docs].flat().flatMap((doc) =>
    doc.pages.map((page) => ({ doc, page, n: (doc.pageIndexOffset ?? 0) + page.index })));
  const spreads = [];
  let verso = null;
  for (const p of pages) {
    if (p.n % 2 === 1) { if (verso) spreads.push([verso, null]); verso = p; }
    else { spreads.push([verso, p]); verso = null; }
  }
  if (verso) spreads.push([verso, null]);
  const density = Math.min(window.devicePixelRatio || 1, 2);
  showPages.painter?.disconnect();
  const painter = new IntersectionObserver((entries) => {
    for (const { isIntersecting, target } of entries) {
      if (!isIntersecting) continue;
      painter.unobserve(target);
      const { doc, page } = target.postext;
      renderPageToCanvas(page, doc, target, { scale: (width * density) / page.width });
    }
  }, { rootMargin: '800px' });
  showPages.painter = painter;
  root.replaceChildren(...spreads.map((pair) => {
    const spread = document.createElement('div');
    spread.className = 'pt-spread';
    for (const p of pair) {
      const figure = document.createElement('figure');
      if (p) {
        const label = p.page.pageLabel || String(p.n + 1);
        const canvas = document.createElement('canvas');
        canvas.postext = p;
        canvas.style.aspectRatio = `${p.page.width} / ${p.page.height}`;
        canvas.setAttribute('role', 'img');
        canvas.setAttribute('aria-label', `Page ${label}`);
        const folio = document.createElement('figcaption');
        folio.textContent = label;
        figure.append(canvas, folio);
        painter.observe(canvas);
      } else figure.className = 'pt-blank';
      spread.append(figure);
    }
    return spread;
  }));
  kitStatus(`${pages.length} ${pages.length === 1 ? 'page' : 'pages'}`);
  document.documentElement.dataset.postext = 'ready';
  return pages.length;
}

/** The desk, the bar and the error reporting, created once. */
function viewer(title) {
  if (!document.getElementById('pt-kit')) {
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit">
      :root { color-scheme: dark; }
      body { margin: 0; background: #0e1014; color: #b9bcc4; font: 13px/1.45 system-ui, sans-serif; }
      #pt-bar { position: sticky; top: 0; z-index: 1; display: flex; flex-wrap: wrap; align-items: center;
        gap: 6px 16px; padding: 10px 16px; background: rgb(14 16 20 / .92); backdrop-filter: blur(6px);
        border-bottom: 1px solid #23262d; }
      #pt-bar strong { color: #f4f1ea; font-weight: 600; }
      #pt-actions { display: flex; gap: 12px; margin-left: auto; }
      #pt-actions a, #pt-actions button { color: #d8a21a; font: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
      #pages { display: grid; justify-items: center; gap: 48px; padding: 32px 16px 72px; }
      .pt-spread { display: flex; }
      .pt-spread figure { margin: 0; width: min(460px, 44vw); }
      .pt-spread canvas { display: block; width: 100%; background: #fff;
        box-shadow: 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figure:first-child canvas { box-shadow: inset -14px 0 14px -14px rgb(0 0 0 / .18), 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figcaption { margin-top: 10px; text-align: center; font: 600 10px/1 system-ui, sans-serif;
        letter-spacing: .18em; text-transform: uppercase; color: #6c7079; }
      .pt-blank { visibility: hidden; }
      @media (max-width: 760px) {
        .pt-spread { flex-direction: column; gap: 32px; }
        .pt-spread figure { width: min(460px, 92vw); }
        .pt-blank { display: none; }
      }
    </style>`);
    document.body.insertAdjacentHTML('afterbegin',
      '<header id="pt-bar"><strong id="pt-title"></strong><span id="pt-status" role="status"></span><span id="pt-actions"></span></header>');
    document.getElementById('pt-title').textContent = document.title || 'Postext';
    addEventListener('error', (event) => kitFail(event.error ?? event.message));
    addEventListener('unhandledrejection', (event) => kitFail(event.reason));
  }
  if (title) document.getElementById('pt-title').textContent = title;
  return document.getElementById('pages')
    ?? document.body.appendChild(Object.assign(document.createElement('main'), { id: 'pages' }));
}

function kitStatus(text) {
  viewer();
  document.getElementById('pt-status').textContent = text;
}

function kitFail(error) {
  document.documentElement.dataset.postext = 'error';
  kitStatus(`Error: ${error?.message ?? error}`);
}

// ─── Kit · images v1 ── recipes with pictures · postext.dev/cookbook ──────────
/** Registers a photo or PNG for the canvas and keeps its bytes for the PDF.
 *  fetch → ImageBitmap never taints the canvas (a plain cross-origin <img> would). */
async function loadImage(fileId, url) {
  const res = await fetch(url);
  if (!res.ok) throw new Error(`Image not found (${res.status}): ${url}`);
  const bytes = new Uint8Array(await res.arrayBuffer());
  registerResourceImage(fileId, await createImageBitmap(new Blob([bytes])));
  (loadImage.bytes ??= new Map()).set(fileId, bytes);
}

/** Registers SVG markup (drawn in code, or fetched) as a vector image. */
async function loadSvg(fileId, svg) {
  const img = new Image();
  img.src = `data:image/svg+xml;charset=utf-8,${encodeURIComponent(svg)}`;
  await img.decode();
  registerResourceImage(fileId, img);
  (loadImage.bytes ??= new Map()).set(fileId, new TextEncoder().encode(svg));
}

/** renderToPdf({ resourceBytes: imageBytes }) */
function imageBytes(fileId) { return loadImage.bytes?.get(fileId); }

/** renderToHtml({ resourceImageUrl: imageUrl }) */
function imageUrl(fileId) {
  const bytes = imageBytes(fileId);
  if (!bytes) return undefined;
  imageUrl.urls ??= new Map();
  if (!imageUrl.urls.has(fileId)) {
    const type = /\.svg$/i.test(fileId) ? 'image/svg+xml' : /\.png$/i.test(fileId) ? 'image/png' : 'image/jpeg';
    imageUrl.urls.set(fileId, URL.createObjectURL(new Blob([bytes], { type })));
  }
  return imageUrl.urls.get(fileId);
}

// ─── /Kit ───────────────────────────────────────────────────────────────────────