根据台词稿重新嵌字的《小辣椒和胡萝卜》

// ═══ Postext Cookbook · Nº 155 · A Pepper&Carrot page re-lettered from its transcript ═══
// https://postext.dev/en/cookbook/pepper-and-carrot-page
// Code: MIT · Text and art: David Revoy and translators, Pepper&Carrot ep. 8 (CC BY 4.0)
// Fonts: Comic Neue, Bangers, Grenze Gotisch and 11 more (OFL) · Needs postext ≥ 1.21.0
//
// Two pages of an open-licensed webcomic, Pepper&Carrot episode 8 by David Revoy, set again
// from his text-free artwork: the panels are cut from his pages, the speakers' anchors come
// from the tails of his balloons, and the words come from the official translations, so the
// engine letters every edition itself.
import {
  buildDocument, renderPageToCanvas, clearMeasurementCache, registerResourceImage,
  loadVerticalAlternates,
} from 'https://esm.sh/postext';
import { renderToPdf, decompressWoff2 } from 'https://esm.sh/postext-pdf';

const LANG = 'zh'; // @lang: the sample's language: 'en' | 'es' | 'ca' | 'zh' | 'ar' | 'ja' | 'pt'
const RECIPE = 'pepper-and-carrot-page';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: Pepper's red, the demons' black and a warm ink
const palette = {
  ink: '#241a14', // lettering and the title page
  accent: '#a8241c', // Pepper's red: the title and the sound effect
  demon: '#0f0f0f', // the demons' balloons, as Revoy letters them
  gilt: '#e4cf96', // the title tooled on the spell book's cover
  plate: '#151a20', // the dark halo that lifts the gilt off the cover
  muted: '#6a5c52', // credits and folios
  paper: '#fffdf8',
};
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' } })),
  { id: 'main-color', name: 'accent (defaults)', value: { hex: palette.accent, model: 'hex' } },
];
// #endregion

// #region editions: the lettering, sound-effect, demon, title-page and book-title faces
const [LETTERING, SFX, DEMON, TEXT, PLATE] = t({
  en: ['Comic Neue', 'Bangers', 'Grenze Gotisch', 'Source Serif 4', 'Zen Antique'],
  es: ['Comic Neue', 'Bangers', 'Grenze Gotisch', 'Source Serif 4', 'Zen Antique'],
  ca: ['Comic Neue', 'Bangers', 'Grenze Gotisch', 'Source Serif 4', 'Zen Antique'],
  ja: ['Zen Antique', 'Dela Gothic One', 'Dela Gothic One', 'Noto Serif JP', 'Zen Antique'],
  zh: ['ZCOOL KuaiLe', 'ZCOOL QingKe HuangYou', 'ZCOOL QingKe HuangYou', 'Noto Serif SC',
    'Noto Sans SC'],
  ar: ['Playpen Sans Arabic', 'Lalezar', 'Lalezar', 'Noto Naskh Arabic', 'Lalezar'],
  pt: ['Comic Neue', 'Bangers', 'Grenze Gotisch', 'Source Serif 4', 'Zen Antique'],
});
// #endregion

// #region answer: Revoy's page grid, his speakers, and one balloon style per voice
// The Markdown is the episode's transcript turned into a script, one line per balloon:
//   :::page{split="29.9 / 49.3 / *"}        the page's three tiers, measured on his page
//   ::panel{art=e08p05-1}
//   pepper{shout break}: How could they do this to me ?!! To **me** !!!
//   monster: Monšters of Chaosāh àt your šeŗvice!
//   sfx{plate at="77.3% 14.4%" rotate=-11 skew=-8}: Incantations\
//     for Demons of\
//     CHAOSAH\
//     Vol .1                                 the book's title, a line per line of the cover
// The cast gives the demons Revoy's black balloons and a blackletter voice (its diacritics are
// his: the demons speak with an accent); 'plate' gilds the title on the book's cover.
const comics = {
  gutter: { horizontal: mm(5.4), vertical: mm(2.4) }, // his white gutters, measured
  panel: { borderWidth: pt(0), background: col('paper') }, // no frames: the art meets the white
  lettering: { fontFamily: LETTERING, fontSize: pt(10), color: col('ink'), inset: mm(2) },
  balloonStyles: [
    { id: 'speech', stroke: col('ink'), strokeWidth: pt(0.8) },
    { id: 'shout', stroke: col('ink'), strokeWidth: pt(1) },
    { id: 'caption', fill: col('paper'), stroke: col('ink') },
    { id: 'sfx', fontFamily: SFX, color: col('accent'), haloColor: col('paper') },
    { id: 'plate', shape: 'none', tail: 'none', fontFamily: PLATE, fontScale: 0.88,
      align: 'center', aspect: 3, color: col('gilt'), halo: pt(0.5), haloColor: col('plate'),
      letterSpacing: pt(0.2) }, // text tooled on an object, here a book's cover
  ],
  cast: [{ id: 'pepper', name: 'Pepper' }, { id: 'carrot', name: 'Carrot' },
    { id: 'monster', name: t({ en: 'Monsters of Chaosah', es: 'Demonios de Caosah',
      ca: 'Monstres del Chaosah', zh: '浑沌魔兽', ar: 'وحوش الفوضى', ja: 'ケイオサーの怪物',
      pt: 'Monstros do Caosah' }),
    fill: col('demon'), color: col('paper'), fontFamily: DEMON }],
  runningHeads: true, // the folio on comic pages
};
// #endregion

const footer = { elements: [{ kind: 'text', id: 'folio', content: '{pageNumber}', pages: 'comic',
  fontFamily: TEXT, fontSize: pt(7.5), color: col('muted'), align: 'center',
  placement: { anchor: { to: 'page', edge: 'bottom' }, offset: { x: mm(0), y: mm(-3) } } }] };

const config = () => ({ // a factory: the engine caches resolved configs per object
  locale: t({ en: 'en-gb', es: 'es', ca: 'ca', ja: 'ja', zh: 'zh-Hans', ar: 'ar', pt: 'pt-BR' }),
  colorPalette, comics,
  // Revoy's pages are A4 with 8.5 mm of white around the art.
  page: { sizePreset: 'custom', width: mm(210), height: mm(297), dpi: 150,
    backgroundColor: col('paper'),
    margins: { top: mm(8.5), bottom: mm(8.7), left: mm(8.5), right: mm(8.2) } },
  layout: { layoutType: 'single' },
  bodyText: { fontFamily: TEXT, fontSize: pt(10), lineHeight: pt(15), color: col('ink'),
    boldColor: col('ink'), italicColor: col('ink'), referenceColor: col('ink'), textAlign: 'left',
    firstLineIndent: pt(0), paragraphSpacing: true, hyphenation: { enabled: false } },
  headings: { fontFamily: LETTERING, color: col('ink'), fontWeight: 700,
    levels: [
      // Restated: any headings object drops the H1 break (gotcha: headings-drop-h1-break).
      { level: 1, fontSize: pt(30), lineHeight: pt(36), color: col('accent'), marginTop: mm(70),
        marginBottom: pt(15), breakBefore: { enabled: true, parity: 'any' } },
      { level: 2, fontSize: pt(10), lineHeight: pt(15), marginTop: mm(20), marginBottom: pt(4) },
    ] },
  paragraphStyles: [{ id: 'lead', fontSize: pt(13), lineHeight: pt(19) },
    { id: 'credits', fontSize: pt(8.5), lineHeight: pt(12), color: col('muted'),
      spaceBetween: pt(6) }],
  header: { elements: [] }, footer,
});

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`# 第8集：小辣椒的生日
Markdown样例 · 40行 · content.zh.md

:::paragraphs{style="lead"}
本集第5、6页，取自 David Revoy 不含文字的原画。对白框和文字由 Postext 依据官方译本重新排出。
:::

## 制作人员

:::paragraphs{style="credits"}
2015年6月 - 绘图及脚本：David Revoy - 翻译：庄冉

Art & Scenario: David Revoy — Translation: Ran Zhuang

许可协议：知识共享 署名 4.0（CC BY 4.0）

本作品为 David Revoy《小辣椒的生日》（CC BY 4.0）的衍生作品：Postext 依据官方简体中文译本重新制作了对白框与文字，并重新排版。

www.peppercarrot.com
:::

:::page{split="29.9 / 49.3 / *"}
::panel{art=e08p05-1}
pepper{shout break}: 她们怎么可以这样对待**我！！！**
sfx{plate at="77.3% 14.4%" rotate=-11 skew=-8}: 浑沌恶魔\
  召唤术\
  卷一
::panel{art=e08p05-2}
pepper{shout}: …既然她们如此不可靠！
::panel{art=e08p05-3}
sfx{at="18.6% 66%" rotate=-28}: 呜呜呜呜呜呜呜……
:::

:::page{split="38.2 / 18.7 / *"}
::panel{art=e08p06-1}
monster: 浑沌魔兽为您效劳
monster{join=false}: 向谁发起攻击？…
::panel{art=e08p06-2}
::panel{art=e08p06-3}
caption{at=bottom-end}: 第8集：小辣椒的生日\
  完
:::
`; // content.<lang>.md, inlined by the Cookbook

// #region art: the six panels: safe areas and the speakers his balloon tails point at
// From the episode's pipeline: panels cut from the text-free pages, anchors where the tails of
// the English balloons end. Fractions of each picture, the same in every language.
const area = (x, y, width, height) => ({ x, y, width, height });
const ART = {
  'e08p05-1': { width: 1200, height: 500, safeArea: area(0.02, 0.03, 0.85, 0.93),
    anchors: [{ id: 'pepper', x: 0.4249, y: 0.6863 }] },
  'e08p05-2': { width: 1200, height: 823, safeArea: area(0.1, 0.09, 0.77, 0.81),
    anchors: [{ id: 'pepper', x: 0.7858, y: 0.6274 }] },
  'e08p05-3': { width: 1200, height: 342, safeArea: area(0.09, 0.12, 0.81, 0.88),
    anchors: [{ id: 'sfx', x: 0.1861, y: 0.66 }] },
  'e08p06-1': { width: 1200, height: 646, safeArea: area(0.15, 0.06, 0.73, 0.9),
    anchors: [{ id: 'monster', x: 0.4808, y: 0.293 }] },
  'e08p06-2': { width: 1200, height: 290, safeArea: area(0.59, 0.15, 0.3, 0.77) },
  'e08p06-3': { width: 1200, height: 730, safeArea: area(0.09, 0.1, 0.77, 0.7) },
};
const ALT = {
  'e08p05-1': t({ en: 'Lightning. Pepper, furious, pulls a book with a demon’s face on its cover '
      + 'from the shelf. Carrot is terrified.',
    es: 'Relámpagos. Pimienta, furiosa, saca de la estantería un libro con la cara de un demonio '
      + 'en '
      + 'la tapa. Zanahoria está aterrado.',
    ca: 'Llamps. La Pepper, furiosa, treu del prestatge un llibre amb la cara d’un dimoni a la '
      + 'coberta. En Carrot està aterrit.',
    zh: '电闪雷鸣。小辣椒怒气冲冲地从书架上抽出一本封面有恶魔脸的书。胡萝卜吓坏了。',
    ar: 'برق. فُلفُل غاضبة تسحب من الرف كتابًا على غلافه وجه شيطان، وجزرة مذعور.',
    ja: '稲妻。怒ったペッパーが、表紙に悪魔の顔のある本を棚から引き抜く。キャロットはおびえている。',
    pt: 'Relâmpagos. Pepper, furiosa, tira da estante um livro com a cara de um demônio na capa. '
      + 'Carrot está apavorado.' }),
  'e08p05-2': t({ en: 'From above, in the rain, Pepper draws three glowing red magic circles on '
      + 'the ground with her wand. Carrot watches.',
    es: 'Desde arriba, bajo la lluvia, Pimienta traza con su varita tres círculos mágicos rojos en '
      + 'el suelo. Zanahoria mira.',
    ca: 'Des de dalt, sota la pluja, la Pepper traça amb la vareta tres cercles màgics vermells a '
      + 'terra. En Carrot mira.',
    zh: '俯视：雨中，小辣椒用魔杖在地上画出三个发光的红色魔法阵，胡萝卜在一旁看着。',
    ar: 'من الأعلى، تحت المطر، ترسم فُلفُل بعصاها ثلاث دوائر سحرية حمراء متوهجة على الأرض، وجزرة '
      + 'يراقب.',
    ja: '上から見たところ。雨の中、ペッパーが杖で地面に赤く光る魔法陣を三つ描く。キャロットが見ている。',
    pt: 'Vista de cima, na chuva, Pepper traça com a varinha três círculos mágicos vermelhos e '
      + 'brilhantes no chão. Carrot observa.' }),
  'e08p05-3': t({ en: 'Red light floods the scene. Pepper, grim, holds the open book.',
    es: 'Una luz roja lo inunda todo. Pimienta, seria, sostiene el libro abierto.',
    ca: 'Una llum vermella ho inunda tot. La Pepper, seriosa, aguanta el llibre obert.',
    zh: '红光笼罩一切。小辣椒神情严峻，捧着打开的书。',
    ar: 'ضوء أحمر يغمر المشهد، وفُلفُل متجهّمة تمسك الكتاب مفتوحًا.',
    ja: '赤い光があたりを満たす。ペッパーが険しい顔で、開いた本を持っている。',
    pt: 'Uma luz vermelha inunda a cena. Pepper, séria, segura o livro aberto.' }),
  'e08p06-1': t({ en: 'Pepper and Carrot stand before three huge red-eyed demons that rise in the '
      + 'storm, lightning around them.',
    es: 'Pimienta y Zanahoria ante tres enormes demonios de ojos rojos que se alzan en la '
      + 'tormenta, entre relámpagos.',
    ca: 'La Pepper i en Carrot davant de tres dimonis enormes d’ulls vermells que s’alcen en la '
      + 'tempesta, entre llamps.',
    zh: '小辣椒和胡萝卜站在三个红眼巨魔面前，巨魔在暴风雨中升起，四周电光闪闪。',
    ar: 'فُلفُل وجزرة أمام ثلاثة شياطين ضخمة بعيون حمراء تنهض في العاصفة والبرق حولها.',
    ja: '嵐の中に現れた赤い目の巨大な悪魔三体の前に、ペッパーとキャロットが立つ。まわりに稲妻。',
    pt: 'Pepper e Carrot diante de três demônios enormes de olhos vermelhos que surgem na '
      + 'tempestade, entre relâmpagos.' }),
  'e08p06-2': t({ en: 'Pepper smiles a sly smile.', es: 'Pimienta sonríe con malicia.',
    ca: 'La Pepper somriu amb malícia.', zh: '小辣椒狡黠地一笑。', ar: 'فُلفُل تبتسم ابتسامة ماكرة.',
    ja: 'ペッパーがにやりと笑う。', pt: 'Pepper dá um sorriso malicioso.' }),
  'e08p06-3': t({ en: 'The party: Pepper, Carrot and the three demons drink tea around the table '
      + 'by candlelight, all smiling.',
    es: 'La fiesta: Pimienta, Zanahoria y los tres demonios toman té alrededor de la mesa a la luz '
      + 'de las velas, sonrientes.',
    ca: 'La festa: la Pepper, en Carrot i els tres dimonis prenen te al voltant de la taula a la '
      + 'llum de les espelmes, somrients.',
    zh: '派对：小辣椒、胡萝卜和三个恶魔围着桌子，在烛光下喝茶，个个笑容满面。',
    ar: 'الحفلة: فُلفُل وجزرة والشياطين الثلاثة يشربون الشاي حول المائدة على ضوء الشموع، مبتسمين.',
    ja: 'パーティー。ペッパーとキャロットと三体の悪魔が、ろうそくの明かりのテーブルを囲んでお茶を飲み、'
      + 'みんな笑っている。',
    pt: 'A festa: Pepper, Carrot e os três demônios tomam chá em volta da mesa à luz de velas, '
      + 'todos sorrindo.' }),
};
// #endregion

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
// Every face of the six editions; each edition loads the latin files of all of them and the
// Japanese, Chinese or Arabic files of its own (gotcha: fonts-first).
const FONTS = {
  'Comic Neue': ['400', '400i', '700', '700i'],
  Bangers: ['400'],
  'Grenze Gotisch': ['400', '700'],
  'Source Serif 4': ['400', '700'],
  'Zen Antique': ['400'],
  'Dela Gothic One': ['400'],
  'Noto Serif JP': ['400', '700'],
  'ZCOOL KuaiLe': ['400'],
  'ZCOOL QingKe HuangYou': ['400'],
  'Noto Serif SC': ['400', '700'],
  'Noto Sans SC': ['400'],
  'Playpen Sans Arabic': ['400', '700'],
  Lalezar: ['400'],
  'Noto Naskh Arabic': ['400', '700'],
};

// #region vietnamese: a translator's name the latin-ext file does not cover
// The credits thank Hồ Nhựt Châu. Vietnamese letters live in a Fontsource file of their own,
// which neither loadFonts nor the PDF providers fetch: the page loads it for the credits' face,
// and the PDF provider adds it to that face when the page sets one of its letters.
const VI_RANGE = 'U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,'
  + 'U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB';
const VI = /[ĂăĐđƠơƯưẠ-ỹ]/u;
const viFile = (family, weight) => `https://cdn.jsdelivr.net/npm/@fontsource/`
  + `${fontsourceId(family)}@5/files/${fontsourceId(family)}-vietnamese-${weight}-normal.woff2`;
async function loadVietnamese(family) {
  if (!VI.test(markdown)) return;
  document.fonts.add(await new FontFace(family, `url(${viFile(family, 400)})`,
    { weight: '400', unicodeRange: VI_RANGE }).load());
}
async function pdfFonts(family, weight, style, request) {
  const files = [await comicPdfProvider(family, weight, style, request)].flat();
  const text = String.fromCodePoint(...(request?.codePoints ?? []));
  if (family !== TEXT || !VI.test(text)) return files;
  const res = await fetch(viFile(family, 400));
  return [...files, await decompressWoff2(new Uint8Array(await res.arrayBuffer()))];
}
// #endregion

// ─── 4 · Build & show ───────────────────────────────────────────────────────
const faces = Object.fromEntries([LETTERING, SFX, DEMON, TEXT, PLATE].map((f) => [f, FONTS[f]]));
await loadFonts(FONTS, markdown);
await loadCjkFonts(faces, markdown, { vertical: LANG === 'ja' }); // ja balloons are vertical
await loadArabicFonts(faces, markdown);
await loadComicFonts({ [LETTERING]: FONTS[LETTERING], [SFX]: FONTS[SFX], [DEMON]: FONTS[DEMON] },
  markdown); // the bold and italic the lettering faces do not ship
await loadVietnamese(TEXT);
const panel = async (id, url) => ({ ...(await comicPanel(id, url, { ...ART[id], alt: ALT[id] })),
  note: 'David Revoy, www.peppercarrot.com (CC BY 4.0)' }); // the credit every picture carries
const resources = await Promise.all([
  panel('e08p05-1', asset('e08p05-1.jpg')), panel('e08p05-2', asset('e08p05-2.jpg')),
  panel('e08p05-3', asset('e08p05-3.jpg')), panel('e08p06-1', asset('e08p06-1.jpg')),
  panel('e08p06-2', asset('e08p06-2.jpg')), panel('e08p06-3', asset('e08p06-3.jpg')),
]);
const doc = await buildWithFonts(() => buildDocument({ markdown, resources }, config()), markdown);
showBook(doc, { title: t({ en: 'A Pepper&Carrot page re-lettered from its transcript',
  es: 'Una página de Pepper&Carrot rotulada de nuevo a partir de su transcripción',
  pt: 'Uma página de Pepper&Carrot reletreirada pela transcrição' }) });
offerPdf(() => renderToPdf(doc, { fontProvider: pdfFonts, resourceBytes: imageBytes }),
  `${RECIPE}.pdf`);

工具包 · core, fonts, viewer, pdf, images, cjk, arabic, comics：每道食谱都相同 · 722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 v2 ── the same in every recipe · postext.dev/cookbook
// Postext measures with the loaded faces and caches the widths: load every face
// before the first build, from Fontsource, the files the PDF embeds too.

/** faces = { 'Family Name': ['400', '400i', '700'] }. `text` is the sample:
 *  č ł † α χ also load latin-ext and greek files (kitSubsetsFor). 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',
    greek: 'U+0370-03FF',
  };
  const jobs = [];
  let added = 0;
  for (const [family, specs] of Object.entries(faces)) {
    const id = fontsourceId(family);
    const todo = [...new Set(specs)].map((spec) => [parseInt(spec, 10), spec.endsWith('i') ? 'italic' : 'normal'])
      .filter(([weight, style]) => !hasFace(family, weight, style)); // before any await
    const meta = optional || /[^\0-ÿ]/u.test(text) ? await fontsourceMeta(family) : null;
    const subsets = ['latin', ...kitSubsetsFor(text, meta)];
    for (const [weight, style] of todo) {
      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` and loads any face the pages use that FONTS missed (a regular
 *  one with a warning), then clears the measurement cache and builds 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. */
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' };
}

/** A loaded FontFace covers this family, weight and style (fonts.check() would
 *  also say yes 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;
}

/** The files beyond latin `text` needs that `meta`'s family ships. */
function kitSubsetsFor(text, meta) {
  return [[/[Ā-˿ᴀ-ᶿḀ-ỿ†ℓⱠ-Ɀ꜠-ꟿ]/u, 'latin-ext'], [/[Ͱ-Ͽ]/u, 'greek']]
    .filter(([re, x]) => re.test(text) && meta?.subsets?.includes(x)).map(([, x]) => x);
}

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

/** The family's Fontsource metadata (weights, styles, subsets), 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
/** The pages as spreads on a dark desk, page 1 alone, then verso | recto,
 *  each painted when it scrolls near. */
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 · pdf v2 ── the same in every recipe that exports a PDF
/** The Fontsource files the screen used, as TrueType: the nearest weight the
 *  family ships, upright if it has no italic; latin, then what the face's
 *  letters need (kitSubsetsFor). */
async function fontsourceProvider(family, weight, style, request) {
  const id = fontsourceId(family);
  const meta = await fontsourceMeta(family);
  const weights = meta?.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && meta && !meta.styles.includes('italic') ? 'normal' : style;
  const text = String.fromCodePoint(...(request?.codePoints ?? []));
  const more = kitSubsetsFor(text, meta);
  const files = await Promise.all(['latin', ...more].map(async (subset) => {
    const res = await fetch(`https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-${subset}-${w}-${s}.woff2`);
    if (!res.ok) throw new Error(`Fontsource has no ${family} ${w} ${s} ${subset}`);
    return decompressWoff2(new Uint8Array(await res.arrayBuffer()));
  }));
  return files.length === 1 ? files[0] : files;
}

/** A "Build the PDF" button; then "Open the PDF" (a new tab: CodePen's frame
 *  shows no PDFs) and a download link. */
function offerPdf(makePdf, filename) {
  viewer();
  const button = Object.assign(document.createElement('button'), { type: 'button', textContent: 'Build the PDF' });
  button.dataset.postextPdf = filename;
  button.addEventListener('click', async () => {
    button.disabled = true;
    button.textContent = 'Building the PDF…';
    try {
      const bytes = await makePdf();
      const url = URL.createObjectURL(new Blob([bytes], { type: 'application/pdf' }));
      const size = `${Math.max(1, Math.round(bytes.length / 1024))} KB`;
      button.replaceWith(
        Object.assign(document.createElement('a'), { href: url, target: '_blank', rel: 'noopener', textContent: 'Open the PDF ↗' }),
        Object.assign(document.createElement('a'), { href: url, download: filename, textContent: `Download ${filename} · ${size}` }));
    } catch (error) {
      button.disabled = false;
      button.textContent = 'Build the PDF';
      kitFail(error);
    }
  });
  document.getElementById('pt-actions').append(button);
}

// ─── 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 · cjk v1 ── Chinese, Japanese and Korean books · postext.dev/cookbook
// Fontsource ships a CJK family as about a hundred files per weight, each
// declared in its stylesheet with the unicode-range it covers. The screen
// loads the files the sample touches; the PDF gets the same files for the
// characters its pages set in each face, and embeds each as a subset.
// A book bound on the right (vertical text) is shown with its spreads
// mirrored: page 1 alone on the left of the spine, then [3 | 2].

/** The files of a Fontsource face, read from its stylesheet: { url, range,
 *  ranges }, the last declared first (the order the browser tries them in). */
function cjkSlices(family, weight, style) {
  cjkSlices.cache ??= new Map();
  const id = fontsourceId(family);
  const css = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/${weight}${style === 'italic' ? '-italic' : ''}.css`;
  if (!cjkSlices.cache.has(css)) {
    cjkSlices.cache.set(css, fetch(css)
      .then((res) => {
        if (!res.ok) throw new Error(`Fontsource has no ${family} ${weight} ${style} (${res.status})`);
        return res.text();
      })
      .then((text) => [...text.matchAll(/@font-face\s*{([^}]*)}/g)].map(([, rule]) => {
        const range = /unicode-range:\s*([^;]+);/.exec(rule)?.[1].trim() ?? 'U+0-10FFFF';
        const ranges = range.split(',').map((part) => {
          const [lo, hi = lo] = part.trim().slice(2).split('-');
          return [parseInt(lo, 16), parseInt(hi, 16)];
        });
        return { url: new URL(/url\(([^)]+?\.woff2)\)/.exec(rule)[1], css).href, range, ranges };
      }).reverse()));
  }
  return cjkSlices.cache.get(css);
}

/** The file of `slices` that holds code point `cp`, if any. */
function cjkSliceFor(slices, cp) {
  return slices.find((slice) => slice.ranges.some(([lo, hi]) => cp >= lo && cp <= hi));
}

/** Whether Fontsource serves `family` as a Chinese, Japanese or Korean
 *  family (its subsets name the script). Fails when the API does not
 *  answer: a CJK face taken for a Latin one would paint in a system face. */
async function isCjkFamily(family) {
  const meta = await fontsourceMeta(family);
  if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
  return !!meta.subsets?.some((subset) => /^(chinese|japanese|korean)/.test(subset));
}

/** faces = { 'Noto Serif TC': ['400', '700'] }, as for loadFonts: the
 *  whole FONTS object may be passed, its other families are left to
 *  loadFonts. Adds one FontFace per file of each CJK face with its
 *  unicodeRange, then loads the files `text` touches. `text` is what the
 *  faces set: the sample for the text face; a book in several voices calls
 *  it once per voice (loadCjkFonts({ 'LXGW WenKai TC': ['400'] }, quotes)),
 *  so the heading and quotation faces fetch and check only their own
 *  characters. Fails when a character of `text` is in no file of a face.
 *  List every weight the pages use: a weight left to buildWithFonts gets
 *  the latin file only. With { vertical: true } it also loads each
 *  family's vertical forms (brackets, quotes, pause marks) for the canvas,
 *  which needs loadVerticalAlternates imported from postext. Resolves to
 *  the number of files loaded. */
async function loadCjkFonts(faces, text, { vertical = false } = {}) {
  kitStatus('Loading fonts…');
  let loaded = 0;
  try {
    if (vertical && typeof loadVerticalAlternates !== 'function') {
      throw new Error('loadCjkFonts(…, { vertical: true }) needs loadVerticalAlternates imported from postext');
    }
    for (const [family, specs] of Object.entries(faces)) {
      if (!(await isCjkFamily(family))) continue;
      const twin = [];
      for (const spec of new Set(specs)) {
        const weight = parseInt(spec, 10);
        const style = spec.endsWith('i') ? 'italic' : 'normal';
        const slices = await cjkSlices(family, weight, style);
        const missing = [...new Set(text)].filter((ch) => /\S/.test(ch) && !cjkSliceFor(slices, ch.codePointAt(0)));
        if (missing.length) {
          throw new Error(`${family} ${spec} has no file for ${missing.slice(0, 12).join(' ')}: `
            + `give each face the text it sets (loadCjkFonts({ '${family}': ['${spec}'] }, text))`);
        }
        for (const slice of slices) {
          document.fonts.add(new FontFace(family, `url(${slice.url}) format('woff2')`,
            { weight: String(weight), style, unicodeRange: slice.range }));
          twin.push({ source: slice.url, weight: String(weight), style, unicodeRange: slice.range });
        }
        const font = `${style === 'italic' ? 'italic ' : ''}${weight} 16px "${family}"`;
        loaded += (await document.fonts.load(font, text)).length;
        if (!document.fonts.check(font, text)) throw new Error(`${family} ${spec} did not load for the sample`);
      }
      // The same files under a twin name with the `vert` feature on: the
      // canvas paints the punctuation of vertical lines with it.
      if (vertical && twin.length) await loadVerticalAlternates(family, twin);
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return loaded;
}

/** The PDF font provider for recipes with CJK faces: a family whose
 *  Fontsource subsets are Chinese, Japanese or Korean gets the files that
 *  hold the characters its pages set (`request.codePoints`); any other
 *  family gets the latin file fontsourceProvider fetches (the "pdf" block)
 *  and, when the face sets letters only latin-ext has, that file too. */
async function cjkPdfProvider(family, weight, style, request) {
  if (!(await isCjkFamily(family))) return cjkLatinPdfFiles(family, weight, style, request);
  const meta = await fontsourceMeta(family);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const slices = await cjkSlices(family, w, s);
  const picked = new Set();
  for (const cp of request?.codePoints ?? []) {
    const slice = cjkSliceFor(slices, cp);
    if (slice) picked.add(slice);
  }
  if (!picked.size) picked.add(slices[0]);
  return Promise.all(slices.filter((slice) => picked.has(slice)).map(async (slice) => {
    const res = await fetch(slice.url);
    if (!res.ok) throw new Error(`Fontsource file ${slice.url} (${res.status})`);
    return decompressWoff2(new Uint8Array(await res.arrayBuffer()));
  }));
}

/** A Latin family set next to the CJK faces: its latin file, then its
 *  latin-ext file when the face sets letters only latin-ext has (ō ū in
 *  Hepburn rōmaji, ǎ in pinyin), the file loadFonts adds on screen for
 *  them. Latin comes first: postext-pdf draws a character from the first
 *  file that has it, as the browser takes a character both files hold from
 *  latin. A face Fontsource ships without latin-ext, or whose file does
 *  not come, gets latin alone, and the PDF names the letters it lacks. */
async function cjkLatinPdfFiles(family, weight, style, request) {
  const meta = await fontsourceMeta(family);
  const beyond = [...(request?.codePoints ?? [])].some(cjkLatinExtOnly);
  if (!beyond || !meta?.subsets?.includes('latin-ext')) return fontsourceProvider(family, weight, style);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const id = fontsourceId(family);
  const url = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-latin-ext-${w}-${s}.woff2`;
  const [latin, ext] = await Promise.all([fontsourceProvider(family, weight, style), fetch(url)
    .then(async (res) => (res.ok ? decompressWoff2(new Uint8Array(await res.arrayBuffer())) : null), () => null)]);
  return ext ? [latin, ext] : latin;
}

/** Whether code point `cp` is in Fontsource's latin-ext file and not in
 *  its latin file: Latin Extended-A and -B, IPA, the spacing modifiers and
 *  Latin Extended Additional (loadFonts's test for latin-ext), less the
 *  few latin holds too (ı Œ œ ʻ ʼ ˆ ˚ ˜). */
function cjkLatinExtOnly(cp) {
  if (!((cp >= 0x100 && cp <= 0x2ff) || (cp >= 0x1e00 && cp <= 0x1eff))) return false;
  return ![0x131, 0x152, 0x153, 0x2bb, 0x2bc, 0x2c6, 0x2da, 0x2dc].includes(cp);
}

/** showPages for a book bound on either edge. A right-bound book (the
 *  document says so: doc.binding is 'right' for page.binding 'right' and
 *  for vertical text) lies on the desk as it opens: page 1 alone on the
 *  left of the spine, then [3 | 2], the spine shade on each page's inner
 *  edge. `binding` ('left' | 'right') overrides the document's. */
function showBook(docs, { binding, ...options } = {}) {
  const count = showPages(docs, options);
  const right = (binding ?? [docs].flat()[0]?.binding) === 'right';
  if (!document.getElementById('pt-kit-cjk')) {
    // The pages keep direction ltr: a canvas draws text in the direction its
    // element inherits, and under rtl each run would end where the engine
    // starts it, its brackets mirrored.
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit-cjk">
      .pt-spread[dir="rtl"] canvas { direction: ltr; }
      .pt-spread[dir="rtl"] 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); }
    </style>`);
  }
  // Each pair stays [verso, recto] in the page; right to left, the verso
  // sits on the right. Phones stack the pages in reading order either way.
  for (const spread of document.querySelectorAll('#pages > .pt-spread')) spread.dir = right ? 'rtl' : 'ltr';
  document.getElementById('pages').dataset.binding = right ? 'right' : 'left';
  return count;
}

// ─── Kit · arabic v1 ── Arabic-script faces · postext.dev/cookbook
// Fontsource ships an Arabic family as one file per subset and weight: the
// `arabic` file holds the letters, the harakat, the Arabic-Indic digits, the
// Arabic punctuation and the presentation forms; `latin` and `latin-ext`
// hold the rest. loadFonts loads the latin files; this block adds the arabic
// file of every Arabic family, for the canvas and for the PDF, which shapes
// the letters with HarfBuzz from the same bytes.

/** The code points of Fontsource's `arabic` subset, as its stylesheets
 *  declare them (the same unicode-range the browser picks the file by). A
 *  function, not a const: the kit is inlined after the recipe's top-level
 *  awaits, and a const read before its line throws, where a function
 *  declaration is hoisted. */
function arabicRange() {
  return 'U+0600-06FF,U+0750-077F,U+0870-088E,U+0890-0891,U+0897-08E1,U+08E3-08FF,'
    + 'U+200C-200E,U+2010-2011,U+204F,U+2E41,U+FB50-FDFF,U+FE70-FE74,U+FE76-FEFC,U+102E0-102FB,'
    + 'U+10E60-10E7E,U+10EC2-10EC4,U+10EFC-10EFF,U+1EE00-1EEFF';
}

/** Whether code point `cp` is in the arabic file. */
function inArabicRange(cp) {
  inArabicRange.ranges ??= arabicRange().split(',').map((part) => {
    const [lo, hi = lo] = part.slice(2).split('-');
    return [parseInt(lo, 16), parseInt(hi, 16)];
  });
  return inArabicRange.ranges.some(([lo, hi]) => cp >= lo && cp <= hi);
}

/** Whether Fontsource serves `family` with an `arabic` subset. Fails when
 *  the API does not answer: an Arabic face taken for a Latin one would set
 *  its letters in a system face. */
async function isArabicFamily(family) {
  const meta = await fontsourceMeta(family);
  if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
  return !!meta.subsets?.includes('arabic');
}

/** The arabic file of a face. */
function arabicFileUrl(family, weight, style) {
  const id = fontsourceId(family);
  return `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-arabic-${weight}-${style}.woff2`;
}

/** faces = { Amiri: ['400', '700'] }, as for loadFonts, after it: the whole
 *  FONTS object may be passed, its families without an arabic subset are
 *  left alone. Adds the arabic file of every listed weight of each Arabic
 *  family (the latin files come from loadFonts) and loads it. `text` is
 *  the sample: fails when it holds an Arabic-script character the arabic
 *  file does not cover. List every weight the pages set in Arabic: a weight
 *  left to buildWithFonts gets the latin file only, and its Arabic letters
 *  fall back to a system face. Resolves to the number of files loaded. */
async function loadArabicFonts(faces, text = '') {
  kitStatus('Loading fonts…');
  let loaded = 0;
  try {
    const outside = [...new Set(text)].filter((ch) => /\p{Script=Arabic}/u.test(ch) && !inArabicRange(ch.codePointAt(0)));
    if (outside.length) throw new Error(`Fontsource's arabic files have no ${outside.slice(0, 12).join(' ')}`);
    for (const [family, specs] of Object.entries(faces)) {
      if (!(await isArabicFamily(family))) continue;
      for (const spec of new Set(specs)) {
        const weight = parseInt(spec, 10);
        const style = spec.endsWith('i') ? 'italic' : 'normal';
        const face = new FontFace(family, `url(${arabicFileUrl(family, weight, style)}) format('woff2')`,
          { weight: String(weight), style, unicodeRange: arabicRange() });
        document.fonts.add(await face.load().catch(() => {
          throw new Error(`Fontsource has no arabic file for ${family} ${weight} ${style}`);
        }));
        loaded++;
      }
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return loaded;
}

/** The PDF font provider for recipes with Arabic faces: a family with an
 *  arabic subset gets its arabic file when its pages set Arabic letters
 *  (`request.codePoints`), then its latin file, and its latin-ext file for
 *  the letters beyond latin (transliteration: ā ḥ ʿ). The arabic file comes
 *  first: it also holds the space and the brackets, so a line of Arabic is
 *  shaped as one run and not cut at every space. Any other family goes to
 *  fontsourceProvider (the "pdf" block). */
async function arabicPdfProvider(family, weight, style, request) {
  if (!(await isArabicFamily(family))) return fontsourceProvider(family, weight, style, request);
  const meta = await fontsourceMeta(family);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const wanted = [...(request?.codePoints ?? [])];
  const id = fontsourceId(family);
  const urls = [];
  if (!wanted.length || wanted.some(inArabicRange)) urls.push(arabicFileUrl(family, w, s));
  urls.push(`https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-latin-${w}-${s}.woff2`);
  if (meta.subsets.includes('latin-ext') && wanted.some((cp) => /[Ā-˿Ḁ-ỿ]/u.test(String.fromCodePoint(cp)))) {
    urls.push(`https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-latin-ext-${w}-${s}.woff2`);
  }
  return Promise.all(urls.map(async (url) => {
    const res = await fetch(url);
    if (!res.ok) throw new Error(`Fontsource file ${url} (${res.status})`);
    return decompressWoff2(new Uint8Array(await res.arrayBuffer()));
  }));
}

// ─── Kit · comics v1 ── comic pages · postext.dev/cookbook
// The engine letters a comic in a face per language (defaultComicFont:
// Comic Neue, Zen Antique for Japanese, Noto Sans SC, LXGW WenKai TC,
// Playpen Sans Arabic; defaultComicSfxFont: Bangers, Dela Gothic One,
// ZCOOL KuaiLe, Lalezar) and asks for the bold of a shout or a sound effect
// and the italic of an inner voice. Most of these faces ship one weight and
// no italic: this block declares the file Fontsource does ship for those
// variants, so the canvas measures and paints the letters the PDF embeds
// (the providers snap to the shipped file) and not a bold or a slant the
// browser makes up. It also turns the art manifest into panel resources.

/** faces = { 'Comic Neue': ['400', '700'], Bangers: ['400'] }, as for
 *  loadFonts, after it (and after loadCjkFonts or loadArabicFonts for the
 *  faces of those scripts); the whole FONTS object may be passed. List in
 *  FONTS only what Fontsource ships (Bangers: ['400']): loadFonts fails on
 *  the rest. For each family, the regular, bold, italic and bold italic it
 *  lacks are declared with its nearest file (the regular for the bold, the
 *  upright for the italic) and loaded for `text`. A CJK face needs the cjk
 *  block; an Arabic face setting Arabic, the arabic block. Resolves to the
 *  number of variants added. */
async function loadComicFonts(faces, text = '') {
  kitStatus('Loading fonts…');
  let added = 0;
  try {
    for (const family of Object.keys(faces)) {
      const meta = await fontsourceMeta(family);
      if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
      const weights = meta.weights?.length ? meta.weights : [400, 700];
      const styles = meta.styles?.length ? meta.styles : ['normal'];
      for (const [weight, style] of [[400, 'normal'], [700, 'normal'], [400, 'italic'], [700, 'italic']]) {
        if ((weights.includes(weight) && styles.includes(style)) || hasFace(family, weight, style)) continue;
        const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
        const s = style === 'italic' && styles.includes('italic') ? 'italic' : 'normal';
        for (const { url, range } of await comicFaceFiles(family, w, s, meta, text)) {
          document.fonts.add(new FontFace(family, `url(${url}) format('woff2')`,
            { weight: String(weight), style, unicodeRange: range }));
        }
        await document.fonts.load(`${style === 'italic' ? 'italic ' : ''}${weight} 16px "${family}"`, text || 'A');
        added++;
      }
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return added;
}

/** The files of a shipped face ({ url, range }): a CJK face's slices (the
 *  cjk block reads them from its stylesheet), else latin, the latin-ext
 *  and greek files `text` needs, and the arabic file when `text` holds
 *  Arabic. */
async function comicFaceFiles(family, weight, style, meta, text) {
  if (meta.subsets?.some((subset) => /^(chinese|japanese|korean)/.test(subset))) {
    if (typeof cjkSlices !== 'function') throw new Error(`${family} is a CJK face: list the cjk kit block`);
    return (await cjkSlices(family, weight, style)).map(({ url, range }) => ({ url, range }));
  }
  const id = fontsourceId(family);
  const file = (subset) => `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-${subset}-${weight}-${style}.woff2`;
  const files = ['latin', ...kitSubsetsFor(text, meta)].map((subset) => ({ url: file(subset), range: comicRange(subset) }));
  if (meta.subsets?.includes('arabic') && /\p{Script=Arabic}/u.test(text)) {
    if (typeof arabicRange !== 'function') throw new Error(`${family} sets Arabic: list the arabic kit block`);
    files.unshift({ url: file('arabic'), range: arabicRange() });
  }
  return files;
}

/** The unicode-range loadFonts gives a Fontsource file. A function, not a
 *  const: the kit is inlined after the recipe's top-level awaits. */
function comicRange(subset) {
  return {
    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',
    greek: 'U+0370-03FF',
  }[subset];
}

/** The PDF font provider of a comic in any script: a CJK face goes to
 *  cjkPdfProvider, an Arabic face to arabicPdfProvider, any other to
 *  fontsourceProvider (the "pdf" block). Each embeds the shipped weight
 *  and style nearest to the one asked for, the file loadComicFonts
 *  declared for the canvas. */
async function comicPdfProvider(family, weight, style, request) {
  const subsets = (await fontsourceMeta(family))?.subsets ?? [];
  if (subsets.some((subset) => /^(chinese|japanese|korean)/.test(subset))) {
    if (typeof cjkPdfProvider !== 'function') throw new Error(`${family} is a CJK face: list the cjk kit block`);
    return cjkPdfProvider(family, weight, style, request);
  }
  if (subsets.includes('arabic') && typeof arabicPdfProvider === 'function') {
    return arabicPdfProvider(family, weight, style, request);
  }
  return fontsourceProvider(family, weight, style, request);
}

/** A panel picture as a resource for art= (and pop=): loads `url`
 *  (write asset('lh-arrive.jpg') in the call, so the lint checks the file)
 *  and declares it with `meta`, its entry in the art manifest:
 *  { width, height, alt, safeArea, anchors, avoid }. The safe area is what
 *  every crop keeps, the anchors the speakers' mouths, heads and faces,
 *  the avoid zones what no balloon covers; all in fractions of the picture,
 *  the same in every language. Without width and height, the picture's own
 *  size. Needs the images block. Resolves to the resource. */
async function comicPanel(id, url, meta = {}) {
  const fileId = decodeURIComponent(url.split('/').pop());
  await loadImage(fileId, url);
  let { width, height } = meta;
  if (!width || !height) {
    const bitmap = await createImageBitmap(new Blob([imageBytes(fileId)]));
    ({ width, height } = bitmap);
    bitmap.close();
  }
  return {
    id, typeId: meta.typeId ?? 'figure', kind: 'bitmap', createdAt: 0, updatedAt: 0,
    bitmap: { fileId, format: /\.png$/i.test(fileId) ? 'png' : 'jpeg', width, height },
    ...(meta.alt && { altText: meta.alt }),
    ...(meta.safeArea && { safeArea: meta.safeArea }),
    ...(meta.anchors?.length && { anchors: meta.anchors }),
    ...(meta.avoid?.length && { avoid: meta.avoid }),
  };
}

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