剧本：角色表、说话人与舞台提示

// ═══ Postext Cookbook · Nº 070 · Play script: cast list, speakers and stage directions ═══
// https://postext.dev/en/cookbook/stage-play
// Code: MIT · Text: Oscar Wilde, 1895 (PD, Gutenberg #844), Spanish: the Cookbook · Art: in code
// Fonts: Libre Baskerville, Abril Fatface, Playfair Display SC (OFL 1.1) · Needs postext ≥ 1.4.1
import { buildDocument, renderPageToCanvas, clearMeasurementCache, registerResourceImage,
  parseTSV, mergeCells } from 'https://esm.sh/postext';

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

// ─── 1 · Design ─────────────────────────────────────────────────────────────
const palette = { // every colour in the config links to one of these
  ink: '#221b1f', // the dialogue: a near-black with a little plum in it
  plum: '#5b2349', // the one accent: speakers' names, act titles, the title page's ground
  gold: '#b48a45', // rules and ornaments
  gilt: '#c9aa77', // gold lightened for small type on the plum ground (5.3:1)
  muted: '#6c6168', // stage directions and running heads (5.5:1 on the paper)
  rule: '#d8cbb7', // hairlines between the persons of the cast list
  paper: '#fbf6ec', // a cream stock
};
// The hex travels with the id: designs do not read the palette (gotcha: palette-skips-designs).
const col = (id) => ({ hex: palette[id], model: 'hex', paletteId: id });
const colorPalette = [
  ...Object.entries(palette).map(([id, hex]) => ({ id, name: id, value: { hex, model: 'hex' } })),
  // The engine's defaults link to 'main-color': point it at the accent, so nothing prints blue.
  { id: 'main-color', name: 'plum (defaults)', value: { hex: palette.plum, model: 'hex' } },
];
const [TEXT, DISPLAY, LABEL] = ['Libre Baskerville', 'Abril Fatface', 'Playfair Display SC'];
const [BODY, LEAD] = [9.4, 13.6]; // pt: the dialogue and its leading, the pitch of the grid
const TRIM = { width: 140, height: 216 }; // mm: 5½ × 8½ in, the acting-edition size
const [TOP, INNER, OUTER, LINES] = [20, 18, 15, 36]; // mm, and 36 lines to a full page

// #region answer: a speech is a paragraph: the name in bold, the directions in italic
// Speeches are plain paragraphs, the speaker's name in bold and each stage direction in
// italic; a direction between two speeches is a paragraph of its own, in a container:
//   **LANE.** Yes, sir. *[Hands them on a salver.]*
//   :::paragraphs{style="direction"}
//   *[Enter Lane.]*
//   :::
// The body's two emphasis colours then mark who speaks (plum) and what is done (grey).
const dialogue = {
  fontFamily: TEXT, fontSize: pt(BODY), lineHeight: pt(LEAD), color: col('ink'),
  boldColor: col('plum'), // **ALGERNON.**
  italicColor: col('muted'), // *[Languidly.]*, in a speech or a paragraph of its own
  minWordSpacing: 0.65, maxWordSpacing: 1.8, // justified (the default); limits inside 0.6–2
  firstLineIndent: mm(5), hangingIndent: true, // the name at the margin, the turnovers hung
  maxRuntTracking: 0, // gotcha: runt-tracking-unpainted
};
// Directions: smaller and centred, on the same grid. A paragraph style has no italic switch
// or colour (gotcha: style-italic-colour): the text is written *…* and takes the grey.
const direction = { id: 'direction', fontSize: pt(8.6),
  textAlign: 'center', firstLineIndent: pt(0) };
// #endregion

// #region acts: an act title is a plain first-level heading, centred and set in capitals
// Any headings object drops the H1 break: restated (gotcha: headings-drop-h1-break).
const headings = {
  fontFamily: LABEL, fontWeight: 400, color: col('ink'),
  textAlign: 'center', // every level: the act, the cast list's heads, the scene
  lineHeight: pt(LEAD), marginTop: pt(LEAD), marginBottom: pt(0), // whole lines of the grid
  levels: [
    { level: 1, fontFamily: DISPLAY, fontSize: pt(24), lineHeight: pt(3 * LEAD),
      color: col('plum'), textTransform: 'uppercase',
      breakBefore: { enabled: true, parity: 'odd' } }, // a recto, facing the cast list
    { level: 2, fontSize: pt(13), lineHeight: pt(2 * LEAD) },
    { level: 3, fontSize: pt(9.5), color: col('plum') },
  ],
};
// #endregion

// #region cast: the cast list: a table from tab-separated lines, with merged rows
// One row per line, cells split by tabs. A line with no tab spans the table: mergeCells
// joins its cells (gotcha: merged-cells-hiddenby). Each column has its own alignment.
function billTable(tsv, widths, align, headerRowCount = 0) {
  let model = { ...parseTSV(tsv.trim()), columnWidths: widths, headerRowCount };
  model.rows.forEach((row) => row.forEach((cell, c) => { cell.align = align[c]; }));
  tsv.trim().split('\n').forEach((line, r) => {
    if (line.includes('\t')) return;
    model.rows[r][0].align = 'center';
    const end = { row: r, col: widths.length - 1 };
    model = mergeCells(model, { start: { row: r, col: 0 }, end });
  });
  return model;
}
// One filled header cell: two side by side would show a seam (gotcha: table-fill-seams).
const tableStyle = {
  rules: 'horizontal', borderColor: col('rule'), borderWidth: pt(0.5),
  headerBackground: col('plum'), headerColor: col('paper'), headerFontFamily: LABEL,
  headerFontSize: pt(8.5), headerBold: false, // small capitals from the face itself
  bodyFontSize: pt(8.8), cellPadding: mm(1.5), // the body's face and ink, a size smaller
};
const tableStyles = [{ id: 'scenes', rules: 'none', cellPadding: mm(1) }]; // the scenes
// #endregion

// #region ornament: a resource type for artwork with no number and no caption
// ::resource{id="fleuron"} sets it where it stands (gotcha: resource-double-quotes).
const unnumbered = (id, name, defaultPlacement) => ({ id, name, shortLabel: '', captionPrefix: '',
  numberingTemplate: '{n}', resetOn: 'never', counterFormat: 'decimal', defaultPlacement });
const resourceTypes = [
  unnumbered('ornament', 'Ornament', { position: 'here', width: 0.24, align: 'center' }),
  unnumbered('bill', 'Bill', { position: 'here' }),
];
// #endregion

// #region playbill: the title page, a heading style whose design fills the sheet
// # The Importance of Being Earnest {style="playbill" small="The" big="Importance" …}
// Each attribute is a playbill line in its own face and size, its lineHeight a multiple
// (gotcha: design-lineheight-multiple). The ground is an image and reserves no height
// (gotcha: opener-image-no-reserve): :::pagebreak keeps the title page alone if its foot
// lines move up.
const line = (id, content, font, size, y, color, extra = {}) => ({ kind: 'text', id, content,
  fontFamily: font, fontSize: pt(size), lineHeight: 1, color: col(color), align: 'center',
  // Centred and tracked, a line sits half its tracking left of centre: x puts it back.
  placement: { anchor: { to: 'page', edge: 'top' },
    offset: { x: pt((extra.letterSpacing?.value ?? 0) / 2), y: mm(y) } }, ...extra });
const tracked = (track) => ({ textTransform: 'uppercase', letterSpacing: pt(track) });
const playbill = {
  id: 'playbill', span: 'page', // even in one column (gotcha: opener-clipped-at-top)
  header: { elements: [] }, footer: { elements: [] }, // no heads on p. 2, no folio on p. 1
  advancedDesign: { enabled: true, slot: { elements: [
    { kind: 'image', id: 'ground', resourceId: 'playbill',
      placement: { anchor: { to: 'bleed', edge: 'top-left' }, size: { width: 'fill' } } },
    line('kicker', '{subtitle}', LABEL, 8.5, 36, 'gilt', tracked(1.7)),
    line('small', '{attr.small}', TEXT, 17, 51, 'paper', { italic: true }),
    line('big', '{attr.big}', DISPLAY, 40, 60, 'paper', { textTransform: 'uppercase' }),
    line('link', '{attr.link}', TEXT, 17, 78, 'gilt', { italic: true }),
    line('name', '{attr.name}', DISPLAY, 60, 87, 'paper', { textTransform: 'uppercase' }),
    line('author', '{author}', LABEL, 13, 133, 'paper', tracked(3)),
    line('theatre', '{attr.theatre}', LABEL, 8, 170, 'gilt', tracked(1.6)),
    line('premiere', '{attr.premiere}', TEXT, 8.5, 176, 'paper', { italic: true }),
  ] } },
};
// #endregion

// #region heads: the play on the verso, the act on the recto, folios outside
const head = (id, content, parity, edge, x, style) => ({
  kind: 'text', id, content, parity, pages: 'body', // never on openers or blank pages
  fontFamily: LABEL, fontSize: pt(8.5), letterSpacing: pt(0.8), color: col('muted'),
  textTransform: 'uppercase', ...style,
  placement: { anchor: { to: 'page', edge }, offset: { x: mm(x), y: mm(11) } },
});
const folio = { fontFamily: TEXT, letterSpacing: pt(0), color: col('plum') };
const header = { elements: [
  head('verso-folio', '{pageNumber}', 'even', 'top-left', OUTER, folio),
  head('verso-title', '{title}', 'even', 'top-left', OUTER + 8),
  head('recto-act', '{chapterTitle}', 'odd', 'top-right', -(OUTER + 8)),
  head('recto-folio', '{pageNumber}', 'odd', 'top-right', -OUTER, folio),
] };
// The act's first page carries a drop folio instead, centred under the text block.
const footer = { elements: [{ ...head('drop-folio', '{pageNumber}', 'all', 'top', 0, folio),
  pages: 'opener', align: 'center',
  placement: { anchor: { to: 'container', edge: 'top' }, offset: { y: mm(8) } } }] };
// #endregion

const config = () => ({ // a factory: the engine caches resolved configs per object
  locale: t({ en: 'en-us', es: 'es' }), // hyphenation by exact code (gotcha: hyphenation-locales)
  colorPalette,
  resourceTypes,
  page: {
    sizePreset: 'custom', width: mm(TRIM.width), height: mm(TRIM.height),
    backgroundColor: col('paper'),
    margins: { top: mm(TOP), bottom: mm(TRIM.height - TOP - (LINES * LEAD * 25.4) / 72),
      left: mm(INNER), right: mm(OUTER), mirror: true },
  },
  layout: { layoutType: 'single' },
  bodyText: dialogue,
  headings,
  headingStyles: [playbill],
  paragraphStyles: [direction, { id: 'colophon', fontSize: pt(7.5), color: col('muted'),
    textAlign: 'center', firstLineIndent: pt(0), marginTop: pt(LEAD) }],
  tableStyle,
  tableStyles,
  header,
  footer,
});

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
Markdown样例 · 126行 · content.en.md
title: "The Importance of Being Earnest"
subtitle: "A Trivial Comedy for Serious People"
author: "Oscar Wilde"
---

# The Importance of Being Earnest {style="playbill" small="The" big="Importance" link="of Being" name="Earnest" theatre="St James’s Theatre · London" premiere="First performed on 14 February 1895"}

:::pagebreak

## The Persons of the Play

::resource{id="persons"}

## The Scenes of the Play

::resource{id="scenes"}

:::paragraphs{style="colophon"}
Text: Project Gutenberg eBook #844, in the public domain. Set in Libre Baskerville, Abril Fatface and Playfair Display SC (SIL Open Font License).
:::

# First Act

::resource{id="fleuron"}

### Scene

:::paragraphs{style="direction"}
*Morning-room in Algernon’s flat in Half-Moon Street. The room is luxuriously and artistically furnished. The sound of a piano is heard in the adjoining room.*

*[Lane is arranging afternoon tea on the table, and after the music has ceased, Algernon enters.]*
:::

:::space

**ALGERNON.** Did you hear what I was playing, Lane?

**LANE.** I didn’t think it polite to listen, sir.

**ALGERNON.** I’m sorry for that, for your sake. I don’t play accurately—any one can play accurately—but I play with wonderful expression. As far as the piano is concerned, sentiment is my forte. I keep science for Life.

**LANE.** Yes, sir.

**ALGERNON.** And, speaking of the science of Life, have you got the cucumber sandwiches cut for Lady Bracknell?

**LANE.** Yes, sir. *[Hands them on a salver.]*

**ALGERNON.** *[Inspects them, takes two, and sits down on the sofa.]* Oh!… by the way, Lane, I see from your book that on Thursday night, when Lord Shoreman and Mr. Worthing were dining with me, eight bottles of champagne are entered as having been consumed.

**LANE.** Yes, sir; eight bottles and a pint.

**ALGERNON.** Why is it that at a bachelor’s establishment the servants invariably drink the champagne? I ask merely for information.

**LANE.** I attribute it to the superior quality of the wine, sir. I have often observed that in married households the champagne is rarely of a first-rate brand.

**ALGERNON.** Good heavens! Is marriage so demoralising as that?

**LANE.** I believe it *is* a very pleasant state, sir. I have had very little experience of it myself up to the present. I have only been married once. That was in consequence of a misunderstanding between myself and a young person.

**ALGERNON.** *[Languidly.]* I don’t know that I am much interested in your family life, Lane.

**LANE.** No, sir; it is not a very interesting subject. I never think of it myself.

**ALGERNON.** Very natural, I am sure. That will do, Lane, thank you.

**LANE.** Thank you, sir. *[Lane goes out.]*

**ALGERNON.** Lane’s views on marriage seem somewhat lax. Really, if the lower orders don’t set us a good example, what on earth is the use of them? They seem, as a class, to have absolutely no sense of moral responsibility.

:::paragraphs{style="direction"}
*[Enter Lane.]*
:::

**LANE.** Mr. Ernest Worthing.

:::paragraphs{style="direction"}
*[Enter Jack.]*

*[Lane goes out.]*
:::

**ALGERNON.** How are you, my dear Ernest? What brings you up to town?

**JACK.** Oh, pleasure, pleasure! What else should bring one anywhere? Eating as usual, I see, Algy!

**ALGERNON.** *[Stiffly.]* I believe it is customary in good society to take some slight refreshment at five o’clock. Where have you been since last Thursday?

**JACK.** *[Sitting down on the sofa.]* In the country.

**ALGERNON.** What on earth do you do there?

**JACK.** *[Pulling off his gloves.]* When one is in town one amuses oneself. When one is in the country one amuses other people. It is excessively boring.

**ALGERNON.** And who are the people you amuse?

**JACK.** *[Airily.]* Oh, neighbours, neighbours.

**ALGERNON.** Got nice neighbours in your part of Shropshire?

**JACK.** Perfectly horrid! Never speak to one of them.

**ALGERNON.** How immensely you must amuse them! *[Goes over and takes sandwich.]* By the way, Shropshire is your county, is it not?

**JACK.** Eh? Shropshire? Yes, of course. Hallo! Why all these cups? Why cucumber sandwiches? Why such reckless extravagance in one so young? Who is coming to tea?

**ALGERNON.** Oh! merely Aunt Augusta and Gwendolen.

**JACK.** How perfectly delightful!

**ALGERNON.** Yes, that is all very well; but I am afraid Aunt Augusta won’t quite approve of your being here.

**JACK.** May I ask why?

**ALGERNON.** My dear fellow, the way you flirt with Gwendolen is perfectly disgraceful. It is almost as bad as the way Gwendolen flirts with you.

**JACK.** I am in love with Gwendolen. I have come up to town expressly to propose to her.

**ALGERNON.** I thought you had come up for pleasure?… I call that business.

**JACK.** How utterly unromantic you are!

**ALGERNON.** I really don’t see anything romantic in proposing. It is very romantic to be in love. But there is nothing romantic about a definite proposal. Why, one may be accepted. One usually is, I believe. Then the excitement is all over. The very essence of romance is uncertainty. If ever I get married, I’ll certainly try to forget the fact.

**JACK.** I have no doubt about that, dear Algy. The Divorce Court was specially invented for people whose memories are so curiously constituted.

**ALGERNON.** Oh! there is no use speculating on that subject. Divorces are made in Heaven—*[Jack puts out his hand to take a sandwich. Algernon at once interferes.]* Please don’t touch the cucumber sandwiches. They are ordered specially for Aunt Augusta. *[Takes one and eats it.]*
`; // content.<lang>.md, inlined by the Cookbook
const cast = String.raw`The original cast · St James’s Theatre, 14 February 1895
Markdown样例 · 9行 · content.cast.en.md
**John Worthing**, J.P.	*Mr. George Alexander*
**Algernon Moncrieff**	*Mr. Allen Aynesworth*
**Rev. Canon Chasuble**, D.D.	*Mr. H. H. Vincent*
**Merriman**, butler	*Mr. Frank Dyall*
**Lane**, manservant	*Mr. F. Kinsey Peile*
**Lady Bracknell**	*Miss Rose Leclercq*
**Hon. Gwendolen Fairfax**	*Miss Irene Vanbrugh*
**Cecily Cardew**	*Miss Evelyn Millard*
**Miss Prism**, governess	*Mrs. George Canninge*
`; // content.cast.<lang>.md: the persons, tab-separated
const scenes = String.raw`Act I	Algernon Moncrieff’s Flat in Half-Moon Street, W.
Markdown样例 · 3行 · content.scenes.en.md
Act II	The Garden at the Manor House, Woolton.
Act III	Drawing-Room at the Manor House, Woolton.
*Time: The Present.*
`; // content.scenes.<lang>.md: the acts and their places

// #region art: the title page's ground and double frame, and the carnation fleuron, in mm
let seed = 1895; // Mulberry32, a seeded PRNG: never Math.random() in a recipe
const rand = () => {
  let r = Math.imul((seed = (seed + 0x6d2b79f5) | 0) ^ (seed >>> 15), 1 | seed);
  r = (r + Math.imul(r ^ (r >>> 7), 61 | r)) ^ r;
  return ((r ^ (r >>> 14)) >>> 0) / 4294967296;
};
const f = (n) => +n.toFixed(2);
const mix = (a, b, k) => `#${[1, 3, 5].map((i) => Math.round(parseInt(palette[a].slice(i, i + 2),
  16) * (1 - k) + parseInt(palette[b].slice(i, i + 2), 16) * k).toString(16).padStart(2, '0'))
  .join('')}`;
const svgOf = (w, h, body) => `<svg xmlns="http://www.w3.org/2000/svg" width="${w * 10}" `
  + `height="${h * 10}" viewBox="0 0 ${w} ${h}">${body}</svg>`;
const pts = (list) => list.map(([x, y]) => `${f(x)} ${f(y)}`).join('L');
const poly = (list, fill) => `<path d="M${pts(list)}Z" fill="${fill}"/>`;
const stroke = (list, color, w) => `<path d="M${pts(list)}" fill="none" stroke="${color}" `
  + `stroke-width="${w}" stroke-linecap="round" stroke-linejoin="round"/>`;
const quad = ([x0, y0], [cx, cy], [x1, y1], t) => [
  (1 - t) ** 2 * x0 + 2 * (1 - t) * t * cx + t * t * x1,
  (1 - t) ** 2 * y0 + 2 * (1 - t) * t * cy + t * t * y1];

// A carnation `s` mm tall standing on (cx, cy), seen from the side: three fans of pinked
// petals spring from the rim of a calyx, notched apart in the ground colour behind them.
const DEG = Math.PI / 180;
function carnation(cx, cy, s, [back, mid, front], green, ground) {
  const out = [];
  const [rx, ry] = [cx, cy - s * 0.32]; // the rim of the calyx
  const fan = (from, to, r, lift, petals, fill) => { // a fan from `from`° to `to`°, r mm deep
    const at = (deg, k) => [rx + Math.cos(deg * DEG) * r * k,
      ry - lift + Math.sin(deg * DEG) * r * k * 0.92];
    const edge = [];
    for (let i = 0; i <= petals * 6; i++) { // six teeth to a petal, each petal a rounded lobe
      const lobe = 0.84 + 0.16 * Math.sin((Math.PI * (i % 6)) / 6);
      edge.push(at(from + ((to - from) * i) / (petals * 6),
        (i % 2 ? 0.9 : 1) * lobe * (0.98 + rand() * 0.04)));
    }
    out.push(poly([[rx, ry - lift], ...edge], fill));
    const notch = (to - from) / petals / 14; // half the angle of a notch at the edge
    for (let p = 1; p < petals; p++) { // a thin wedge between two petals
      const deg = from + ((to - from) * p) / petals;
      out.push(poly([at(deg, 0.66), at(deg - notch, 1.1), at(deg + notch, 1.1)], ground));
    }
  };
  fan(-162, -18, s * 0.74, 0, 7, back);
  fan(-146, -34, s * 0.56, s * 0.06, 5, mid);
  fan(-124, -56, s * 0.36, s * 0.1, 3, front);
  // The calyx narrows to the stem; three short sepals rise over the petals, and an outline in
  // the ground colour keeps it clear of them.
  const [a, b] = [s * 0.11, s * 0.045]; // half-widths at the rim and at the stem
  const cup = [[rx - a, ry + s * 0.03], [rx - a * 1.25, ry - s * 0.07],
    [rx - a * 0.45, ry - s * 0.01], [rx, ry - s * 0.1], [rx + a * 0.45, ry - s * 0.01],
    [rx + a * 1.25, ry - s * 0.07], [rx + a, ry + s * 0.03], [cx + b, cy], [cx - b, cy]];
  out.push(`<path d="M${pts(cup)}Z" fill="${green}" stroke="${ground}" `
    + `stroke-width="${f(s * 0.03)}" stroke-linejoin="round"/>`);
  return out.join('');
}
// A scroll: an arm out from the stem that ends in a spiral curl.
function scroll(x0, y0, dir, len, curl, color, w) {
  const list = [];
  for (let i = 0; i <= 24; i++) {
    const t = i / 24;
    list.push([x0 + dir * len * t, y0 + Math.sin(t * Math.PI) * curl * 0.3 - t * curl * 0.25]);
  }
  const [ex, ey] = list[list.length - 1];
  for (let i = 1; i <= 48; i++) {
    const a = (i / 48) * Math.PI * 1.8;
    const r = curl * 0.5 * Math.exp(-0.38 * a);
    list.push([ex + dir * Math.sin(a) * r, ey - curl * 0.5 + Math.cos(a) * r]);
  }
  return stroke(list, color, w);
}
// A carnation leaf: a narrow blade along a curve from its base.
function blade(p0, c, p1, w, fill) {
  const [left, right] = [[], []];
  for (let i = 0; i <= 16; i++) {
    const t = i / 16;
    const [x, y] = quad(p0, c, p1, t);
    const [x2, y2] = quad(p0, c, p1, Math.min(1, t + 0.01));
    const [dx, dy] = [x2 - x, y2 - y];
    const k = (w * Math.sin(Math.PI * Math.min(1, t * 1.15)) ** 0.7) / 2
      / (Math.hypot(dx, dy) || 1);
    left.push([x - dy * k, y + dx * k]);
    right.unshift([x + dy * k, y - dx * k]);
  }
  return poly([...left, ...right], fill);
}
// The fleuron, w × h mm: the carnation between two leaves and two scrolls, on `ground`.
function fleuron(w, h, petals, green, ground) {
  const [cx, base] = [w / 2, h * 0.9];
  const parts = [-1, 1].map((d) => scroll(cx + d * 0.6, base, d, w * 0.38, h * 0.46, green,
    h * 0.035) + blade([cx + d * 0.8, base - 0.2], [cx + d * w * 0.12, base - h * 0.02],
    [cx + d * w * 0.24, base - h * 0.3], h * 0.07, green));
  return svgOf(w, h, parts.join('') + carnation(cx, base, h * 0.88, petals, green, ground));
}
// The title page: a plum sheet, a double gold frame whose rules cross at the corners
// (Oxford corners), and the carnation in gold between the title and the author.
const FLEURON_Y = 109; // mm: the top of the title page's carnation
function playbillArt(W, H) {
  const out = [`<rect width="${W}" height="${H}" fill="${palette.plum}"/>`];
  const frame = (inset, w, reach) => { // four rules `inset` mm in, running `reach` mm past
    const [a, bx, by] = [inset, W - inset, H - inset];
    for (const [p, q] of [[[a - reach, a], [bx + reach, a]], [[a - reach, by], [bx + reach, by]],
      [[a, a - reach], [a, by + reach]], [[bx, a - reach], [bx, by + reach]]]) {
      out.push(stroke([p, q], palette.gold, w));
    }
  };
  frame(9, 0.55, 3.2);
  frame(11, 0.22, -1.2);
  for (const [x, y] of [[9, 9], [W - 9, 9], [9, H - 9], [W - 9, H - 9]]) {
    out.push(`<circle cx="${x}" cy="${y}" r="0.9" fill="${palette.gold}"/>`);
  }
  const petals = [mix('gold', 'plum', 0.35), palette.gold, mix('paper', 'gold', 0.2)];
  const sprig = fleuron(46, 16, petals, palette.gold, palette.plum)
    .replace(/^<svg[^>]*>|<\/svg>$/g, '');
  out.push(`<g transform="translate(${(W - 46) / 2} ${FLEURON_Y})">${sprig}</g>`);
  return svgOf(W, H, out.join(''));
}
await loadSvg('playbill.svg', playbillArt(TRIM.width, TRIM.height));
await loadSvg('fleuron.svg', fleuron(30, 11, [mix('plum', 'ink', 0.4), mix('plum', 'paper', 0.12),
  mix('plum', 'paper', 0.45)], palette.gold, palette.paper));
const svg = (id, w, h, altText) => ({ id, typeId: 'ornament', kind: 'svg', altText,
  svg: { fileId: `${id}.svg`, width: w * 10, height: h * 10 }, createdAt: 0, updatedAt: 0 });
const art = [
  svg('playbill', TRIM.width, TRIM.height, 'A plum title page in a double gold frame whose '
    + 'rules cross at the corners, with a gold carnation between two scrolls.'),
  svg('fleuron', 30, 11, 'Ornament: a plum carnation between two gold scrolls.'),
];
// #endregion
const table = (id, model, styleId) => ({ id, typeId: 'bill', kind: 'table',
  table: { model, styleId }, createdAt: 0, updatedAt: 0 });
const resources = [...art,
  table('persons', billTable(cast, [2, 1], ['left', 'right'], 1)), // the first line heads it
  table('scenes', billTable(scenes, [3, 17], ['right', 'left']), 'scenes'),
];

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = { 'Libre Baskerville': ['400', '400i', '700'], 'Abril Fatface': ['400'],
  'Playfair Display SC': ['400'] }; // all loaded before the first build (gotcha: fonts-first)

// ─── 4 · Build & show ───────────────────────────────────────────────────────
await loadFonts(FONTS, markdown + cast + scenes);
const doc = await buildWithFonts(() => buildDocument({ markdown, resources }, config()), markdown);
showPages(doc, { title: doc.metadata.title }); // the frontmatter's title

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 ───────────────────────────────────────────────────────────────────────