Caderno de caligrafia em dez escritas

// ═══ Postext Cookbook · Nº 161 · Handwriting workbook in ten scripts ═══════════════
// https://postext.dev/en/cookbook/handwriting-workbook
// Code: MIT · Text: original (CC BY 4.0) · Pictures: generated with diffusion models
// Fonts: Playwrite, Playpen Sans Arabic, Klee One and others (SIL OFL) · Needs postext ≥ 1.42.1
import {
  buildDocument, withLoadedFonts, renderPageToCanvas, registerResourceImage,
} from 'https://esm.sh/postext';
import { renderToPdf, decompressWoff2 } from 'https://esm.sh/postext-pdf';

const LANG = 'pt'; // @lang: the language of the workbook (en es ca fr de it pt zh ja ar)
const RECIPE = 'handwriting-workbook';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: a navy ink, one coral accent, the sun and the pale fields of the bands
const palette = {
  ink: '#22304a', // text and the models
  accent: '#bf4630', // kickers, labels, folios
  sun: '#f4b73f', // the boxes' stripe
  tint: '#fdf0da', // opener bands, boxes
  rule: '#7f9ccc', // the ruling
  dots: '#4d5b76', // the dotted letters
  trace: LANG === 'ja' ? '#b4bccb' : '#e7a9a0', // traced over: 描红 in red, なぞり書き in grey
  paper: '#ffffff',
};
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: each language its school's script, its ruling and its faces
// hand: the school model the children copy; ruling: the paper they copy it on; u: its
// x-height in mm (the height of an a), the unit every ruling is drawn in; rise: the room its
// capitals need above a title. The Chinese text is in Song: the Kai face, cut for Hong Kong
// and Taiwan, centres its commas, so it sets only the titles and the squares.
const EDITIONS = {
  en: { hand: 'Playwrite GB J', ruling: 'gb', u: 3.6 },
  es: { hand: 'Playwrite ES', ruling: 'pauta', u: 3.6 },
  ca: { hand: 'Playwrite ES', ruling: 'pauta', u: 3.6 },
  fr: { hand: 'Playwrite FR Trad', ruling: 'seyes', u: 3, rise: 5 },
  de: { hand: 'Playwrite DE VA', ruling: 'lineatur', u: 3.6 },
  it: { hand: 'Playwrite IT Trad', ruling: 'righe', u: 3.6 },
  pt: { hand: 'Playwrite BR', ruling: 'caligrafia', u: 3.2 },
  zh: { hand: 'LXGW WenKai TC', ruling: 'tian', text: 'Noto Serif SC',
    label: 'Noto Sans SC', pinyin: 'Andika', cell: 16 },
  ja: { hand: 'Klee One', ruling: 'masu', text: 'Klee One', label: 'Zen Maru Gothic', cell: 16 },
  ar: { hand: 'Playpen Sans Arabic', ruling: 'satr', u: 3.6,
    text: 'Noto Naskh Arabic', label: 'Baloo Bhaijaan 2' },
};
const ED = { text: 'Andika', label: 'Lexend', rise: 0, ...EDITIONS[LANG] };
const [HAND, TEXT, LABEL] = [ED.hand, ED.text, ED.label];
const CJK = ED.cell !== undefined; // a grid of squares, one character to each
const RTL = LANG === 'ar';
const LW = CJK ? 700 : 600; // the labels' weight: the CJK label faces ship no 600
// Labels in tracked capitals, where the script has capitals.
const caps = (n) => (!CJK && !RTL ? { textTransform: 'uppercase', letterSpacing: pt(n) } : {});
// #endregion

const W = 176; // mm: the type area's width, and every practice block's
// A design laid in the flow of a right-to-left page is mirrored by the engine, so 'left' is
// the start side in every edition: the Arabic book needs no coordinates of its own.
const box = (width, height) => ({ width: mm(width), height: mm(height) });
const at = (to, edge, x = 0, y = 0, size) => ({ anchor: { to, edge },
  offset: { x: mm(x), y: mm(y) }, ...(size && { size }) });
const text = (id, content, fontFamily, size, placement, extra = {}) => ({ kind: 'text', id,
  content, fontFamily, fontSize: pt(size), color: col('ink'), align: 'left', placement,
  ...extra });
const image = (id, resourceId, placement) => ({ kind: 'image', id, resourceId, placement,
  decorative: true });
const label = (id) => text(id, '{titleText}', LABEL, 9, at('container', 'top-left'),
  { fontWeight: LW, color: col('accent'), ...caps(1.2) });

// #region answer: a practice block: the model in the school face, then dots, then nothing
// ### Repasa y escribe {w="nina" model="niña"} draws four rows on the edition's ruling: the
// model and dotted copies, a row of dots, the model and one copy, and an empty row. The
// ruling and the dots are one picture per block ('trazo-' + w, drawn under #region art); the
// models are live text set on its baselines. A design text's baseline falls 0.8 of its line
// below the box top, so a box of line L set at baseline − 0.8 L puts the letters on the line.
const G = CJK ? null : geometry(ED.ruling, ED.u); // rows, baselines and the face's size
const LABEL_H = 7; // mm: the block's label above its ruling
const model = (id, row, extra = {}) => text(id, '{attr.model}', HAND, G.size / 0.3528,
  at('container', 'top-left', 0, LABEL_H + G.base[row] - 0.8 * G.line,
    { width: mm(W) }), { lineHeight: mm(G.line), overflow: 'clip', ...extra });
const wordBlock = (rows, again = true) => ({ enabled: true,
  minHeight: mm(LABEL_H + G.height(rows)), slot: { elements: [label('label'),
    image('trazo', 'trazo-{attr.w}', at('container', 'top-left', 0, LABEL_H,
      box(W, G.height(rows)))),
    model('model-1', 0),
    ...(again ? [model('model-3', 2)] : []), // a sentence is written out once
  ] } });
// #endregion

// #region squares: the Chinese and Japanese blocks, a character to a square
// ### 写一写 {c1="日" c2="月"}: each character in the first square of its row, three copies to
// trace in the pale red (描红) or grey (なぞり書き) of the next squares, then empty ones. A
// Han or kana character is one em wide, so tracking of (square − em) sets one per square.
const [CELL, EM] = [ED.cell ?? 16, (ED.cell ?? 16) * 0.72]; // mm: the square, its character
const SQUARES = Math.floor(W / CELL);
const row = (n, y, content, x, color) => text(`r${n}-${x}`, content, HAND, EM / 0.3528,
  at('container', 'top-left', x * CELL + (CELL - EM) / 2, y + (CELL - EM) / 2 + EM * 0.06,
    box(W - x * CELL, EM)),
  { lineHeight: mm(EM), letterSpacing: mm(CELL - EM), overflow: 'clip', color: col(color) });
// A sentence (####) takes three rows: written out, traced, and a row to write it alone.
const squareBlock = (rows, sentence) => ({ enabled: true, minHeight: mm(LABEL_H + rows * CELL),
  slot: { elements: [label('label'), image('grid', `squares-${rows}`,
    at('container', 'top-left', 0, LABEL_H, box(SQUARES * CELL, rows * CELL))),
  ...(sentence ? [row(0, LABEL_H, '{attr.model}', 0, 'ink'),
    row(1, LABEL_H + CELL, '{attr.model}', 0, 'trace')] : Array.from({ length: rows }, (_, n) => [
    row(n, LABEL_H + n * CELL, `{attr.c${n + 1}}`, 0, 'ink'),
    row(n, LABEL_H + n * CELL, `{attr.c${n + 1}}{attr.c${n + 1}}{attr.c${n + 1}}`, 1, 'trace'),
  ]).flat()),
  ] } });
// Pinyin on four lines and three spaces (四线三格), ##### {model="bā"}: the syllable, copies
// to trace in the pale red, the syllable again and room after it.
const P = ED.pinyin ? geometry('sixian', 3.6) : null;
const pinyin = (id, n, x, content, color) => text(id, content, ED.pinyin, P.size / 0.3528,
  at('container', 'top-left', x, LABEL_H + P.base[n] - 0.8 * P.line, { width: mm(W - x) }),
  { lineHeight: mm(P.line), overflow: 'clip', color: col(color) });
const copies = Array(5).fill('{attr.model}').join('\u00a0\u00a0\u00a0\u00a0');
const pinyinBlock = P && { enabled: true, minHeight: mm(LABEL_H + P.height(3)),
  slot: { elements: [label('label'),
    image('lines', 'sixian', at('container', 'top-left', 0, LABEL_H,
      box(W, P.height(3)))),
    pinyin('p1', 0, 0, '{attr.model}', 'ink'), pinyin('p1-copies', 0, 36, copies, 'trace'),
    pinyin('p2', 1, 0, copies, 'trace'), pinyin('p3', 2, 0, '{attr.model}', 'ink'),
  ] } };
// #endregion

// #region opener: a tinted band with the lesson's letters in a disc and its picture
const BAND = 40; // mm
const opener = { enabled: true, minHeight: mm(BAND + 7), slot: { elements: [
  { kind: 'box', id: 'band', decorative: true, style: { backgroundColor: col('tint'),
    borderRadius: mm(5) }, placement: at('container', 'top-left', 0, 0, box(W, BAND)) },
  text('letters', '{attr.letras}', HAND, CJK ? 30 : 26, at('container', 'top-left', 5, 5,
    box(40, 30)),
  { align: 'center', verticalAlign: 'middle', color: col('accent'), overflow: 'clip',
    box: { backgroundColor: col('paper'), borderRadius: mm(15) } }),
  text('kicker', '{attr.kicker}', LABEL, 9, at('container', 'top-left', 52, 8),
    { fontWeight: LW, color: col('accent'), ...caps(1.2) }),
  text('title', '{titleText}', HAND, CJK ? 26 : 24, at('container', 'top-left', 52,
    15 + ED.rise, { width: mm(80) }), { lineHeight: 1.25 }),
  { kind: 'box', id: 'card', decorative: true, style: { backgroundColor: col('paper'),
    borderRadius: mm(4) }, placement: at('container', 'top-right', -4, 3, box(34, 34)) },
  image('picture', '{attr.pic}', at('container', 'top-right', -5, 4, box(32, 32))),
] } };
// #endregion

// #region pages: the cover, the certificate and the picture dictionary
// The cover: a painted scene to the bleed, the title in the school face, a line for a name.
const COVER = 178; // mm from the top edge: the foot of the painting
const cover = { id: 'portada', header: { elements: [] }, footer: { elements: [] },
  advancedDesign: { enabled: true, slot: { elements: [
    image('scene', 'cover', at('page', 'top-left', 0, 0, { width: 'fill', height: mm(COVER) })),
    text('kicker', '{attr.kicker}', LABEL, 11, at('page', 'top', 0, COVER + 10),
      { align: 'center', fontWeight: LW, color: col('accent'), ...caps(1.6) }),
    text('title', '{titleText}', HAND, CJK ? 48 : 46, at('page', 'top', 0, COVER + 18 + ED.rise),
      { align: 'center', lineHeight: 1.2 }),
    text('name', '{attr.nombre}', LABEL, 12, at('page', 'top', -W / 2 + 24, COVER + 58),
      { color: col('ink') }),
    { kind: 'rule', id: 'name-line', direction: 'horizontal', thickness: pt(1),
      color: col('rule'), placement: at('page', 'top', 14, COVER + 64, { width: mm(110) }) },
    text('colophon', '{attr.colofon}', LABEL, 7, at('page', 'top', 0, 262, { width: mm(W) }),
      { align: 'center', color: col('dots'), lineHeight: 1.4 }),
  ] } } };
// The last page: the same frame as a certificate, the child's name and the date to fill in.
const diploma = { id: 'diploma', header: { elements: [] }, footer: { elements: [] },
  advancedDesign: { enabled: true, minHeight: mm(250), slot: { elements: [
    { kind: 'box', id: 'frame', decorative: true, style: { borderColor: col('sun'),
      borderWidth: pt(5), borderRadius: mm(8), backgroundColor: col('paper') },
    placement: at('container', 'top-left', 0, 4, box(W, 244)) },
    image('picture', 'medal', at('container', 'top', 0, 22, box(70, 70))),
    text('title', '{titleText}', HAND, CJK ? 40 : 38, at('container', 'top', 0, 104,
      { width: mm(W - 20) }), { align: 'center', color: col('accent'), lineHeight: 1.2 }),
    text('body', '{attr.texto}', TEXT, 15, at('container', 'top', 0, 136, { width: mm(130) }),
      { align: 'center', lineHeight: 1.45 }),
    ...[0, 1].map((n) => text(`field-${n}`, `{attr.${['nombre', 'fecha'][n]}}`, LABEL, 11,
      at('container', 'top-left', 28, 186 + n * 22), { color: col('dots') })),
    ...[0, 1].map((n) => ({ kind: 'rule', id: `line-${n}`, direction: 'horizontal',
      thickness: pt(1), color: col('rule'),
      placement: at('container', 'top-left', 28, 192 + n * 22, { width: mm(W - 56) }) })),
  ] } } };
// The picture dictionary, ## {p1="cat" w1="gato" …}: four pictures to a row, each word under
// its picture in the school face, and a line to copy it on.
const SLOT = W / 4;
const dictionary = { enabled: true, minHeight: mm(58),
  slot: { elements: [0, 1, 2, 3].flatMap((n) => [
    image(`p${n}`, `{attr.p${n + 1}}`, at('container', 'top-left', n * SLOT + (SLOT - 34) / 2,
      0, box(34, 34))),
    text(`w${n}`, `{attr.w${n + 1}}`, HAND, CJK ? 20 : 17, at('container', 'top-left',
      n * SLOT, 36, box(SLOT, 10)), { align: 'center', overflow: 'clip' }),
    { kind: 'rule', id: `l${n}`, direction: 'horizontal', thickness: pt(0.75),
      color: col('rule'), placement: at('container', 'top-left', n * SLOT + 4, 54,
        { width: mm(SLOT - 8) }) },
  ]) } };
// #endregion

// The folio in an accent disc at the outer foot, the book's title beside it.
const foot = (parity, edge, side) => [
  text(`folio-${parity}`, '{pageNumber}', LABEL, 10, { anchor: { to: 'page', edge },
    offset: { x: mm(18 * side), y: mm(-9) }, size: box(8, 8) }, { parity, align: 'center',
    verticalAlign: 'middle', fontWeight: 700, color: col('paper'), lineHeight: 1.17,
    box: { backgroundColor: col('accent'), borderRadius: mm(4) } }),
  text(`title-${parity}`, '{title} · {subtitle}', LABEL, 7.5, { anchor: { to: 'page', edge },
    offset: { x: mm(29 * side), y: mm(-11) } },
  { parity, color: col('dots'), align: side > 0 ? 'left' : 'right', ...caps(1) }),
];

const config = {
  // Hyphenation, punctuation, direction and binding follow the edition's language.
  locale: t({ en: 'en-gb', es: 'es', ca: 'ca', fr: 'fr', de: 'de', it: 'it', pt: 'pt-BR',
    zh: 'zh-Hans', ja: 'ja', ar: 'ar' }),
  resourceTypes: [{ id: 'dibujo', name: 'Dibujo', shortLabel: '', captionPrefix: '',
    numberingTemplate: '', resetOn: 'never', counterFormat: 'decimal',
    defaultPlacement: { position: 'here' } }],
  colorPalette,
  page: { sizePreset: 'custom', width: mm(210), height: mm(297), dpi: 150,
    margins: { top: mm(16), bottom: mm(22), left: mm(18), right: mm(16), mirror: true } },
  layout: { layoutType: 'single' },
  bodyText: {
    fontFamily: TEXT, fontSize: pt(CJK ? 13.5 : 14), lineHeight: pt(RTL ? 25 : 20),
    color: col('ink'), boldColor: col('ink'), italicColor: col('ink'),
    referenceColor: col('ink'), textAlign: RTL || CJK ? 'justify' : 'left',
    firstLineIndent: pt(0), paragraphSpacing: true, hyphenation: { enabled: !CJK && !RTL },
    optimalLineBreaking: true, avoidWidows: true, avoidOrphans: true, avoidRunts: true,
  },
  headings: {
    fontFamily: HAND, color: col('ink'), fontWeight: 400,
    levels: [
      { level: 1, breakBefore: { enabled: true, parity: 'any' }, marginTop: pt(0),
        marginBottom: mm(3), advancedDesign: opener },
      { level: 2, marginTop: mm(3), marginBottom: mm(3), advancedDesign: dictionary },
      { level: 3, marginTop: mm(4), marginBottom: mm(2),
        advancedDesign: CJK ? squareBlock(4) : wordBlock(4) },
      { level: 4, marginTop: mm(4), marginBottom: mm(2),
        advancedDesign: CJK ? squareBlock(3, true) : wordBlock(3, false) },
      ...(P ? [{ level: 5, marginTop: mm(4), marginBottom: mm(2), advancedDesign: pinyinBlock }]
        : []),
    ],
  },
  headingStyles: [cover, diploma],
  chipStyles: [ // a blank to write a letter in, and a letter tile
    { id: 'hueco', fontFamily: LABEL, background: col('paper'), borderColor: col('rule'),
      borderWidth: pt(1), borderRadius: mm(1.2), paddingX: mm(4), paddingY: em(0.12) },
    { id: 'letra', fontFamily: HAND, background: col('tint'), borderColor: col('sun'),
      borderWidth: pt(1), borderRadius: mm(1.6), paddingX: mm(2), paddingY: em(0.08) }],
  calloutStyles: [{ id: 'recuerda', background: col('tint'), borderRadius: mm(3),
    stripe: { enabled: true, side: 'left', width: pt(4), color: col('sun') },
    padding: { top: mm(3), right: mm(5), bottom: mm(3.5), left: mm(5) },
    titleStyle: { fontFamily: LABEL, fontSize: pt(9), fontWeight: LW, color: col('accent'),
      ...caps(1.2) },
    body: { fontFamily: TEXT, fontSize: pt(12), lineHeight: pt(RTL ? 21 : 17),
      color: col('ink'), boldColor: col('ink'), italicColor: col('ink'),
      firstLineIndent: pt(0) } }],
  header: { elements: [] },
  footer: { elements: [...foot('even', 'bottom-left', 1), ...foot('odd', 'bottom-right', -1)] },
};

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
Amostra em Markdown · 134 linhas · content.pt.md
title: "Aprendo a escrever"
subtitle: "Caderno de caligrafia 1"
---

# Aprendo a escrever {style="portada" kicker="Caderno de caligrafia · Letra cursiva" nombre="Meu nome é" colofon="Composto em Playwrite BR, Andika e Lexend (SIL OFL) · Texto original (CC BY 4.0) · Ilustrações geradas com modelos de difusão"}

# Antes de começar {kicker="Aquecendo a mão" letras="a b c" pic="grip"}

Sente-se com as costas retas e os dois pés no chão. Segure o lápis com três dedos, como uma pinça, sem apertar. Cubra os pontinhos da esquerda para a direita sem tirar o lápis do papel.


### Ondas do mar {w="waves"}

### Voltinhas de caracol {w="loops"}

# As vogais {kicker="Lição 1" letras="a e i o u" pic="owl"}

Em português são cinco as vogais: **a, e, i, o, u**. Toda palavra tem pelo menos uma vogal. Na letra cursiva, cada vogal começa com um traço que sobe e se liga à letra seguinte sem tirar o lápis do papel.

### Cubra e escreva {w="aeiou" model="a e i o u"}

### Cubra e escreva {w="ovo" model="ovo"}

Complete com a vogal que falta: b:chip[ ]{style="hueco"}la · c:chip[ ]{style="hueco"}sa · p:chip[ ]{style="hueco"}to · s:chip[ ]{style="hueco"}l

:::callout{type="recuerda" title="Lembre-se"}
O **i** tem um pingo. Coloque o pingo no final, quando a palavra estiver pronta.
:::

# Sílabas simples {kicker="Lição 2" letras="m p b" pic="kite"}

Junte o **m**, o **p** ou o **b** com uma vogal e você forma uma sílaba: ma, pa, ba. O **m** tem três pontes, o **p** desce abaixo da linha e o **b** sobe com uma laçada.

### Cubra e escreva {w="pipa" model="pipa"}

### Cubra e escreva {w="bola" model="bola"}

Junte e leia: :chip[ma]{style="letra"} + :chip[pa]{style="letra"} · :chip[bo]{style="letra"} + :chip[la]{style="letra"} · :chip[pi]{style="letra"} + :chip[pa]{style="letra"} · :chip[mo]{style="letra"} + :chip[la]{style="letra"}

:::callout{type="recuerda" title="Lembre-se"}
Antes de **p** e de **b** se escreve sempre **m**: campo, bombom, sempre.
:::

# O til {kicker="Lição 3" letras="ã õ" pic="dog"}

O **til** é uma ondinha em cima do **a** ou do **o**. Ele faz o som sair pelo nariz: mão, pão, cão, limões. Escreva a palavra inteira e coloque o til no final.

### Cubra e escreva {w="mao" model="mão"}

### Cubra e escreva {w="limoes" model="limões"}

ã ou õ? p:chip[ ]{style="hueco"}o · c:chip[ ]{style="hueco"}o · lim:chip[ ]{style="hueco"}es · bal:chip[ ]{style="hueco"}o

:::callout{type="recuerda" title="Lembre-se"}
Sem o til a palavra muda: **lá** é um lugar e **lã** vem da ovelha.
:::

# A cedilha {kicker="Lição 4" letras="ç" pic="apple"}

O **ç** é um c com um rabinho embaixo, a **cedilha**. Ela faz o c soar como s antes de a, o, u: maçã, coração, açúcar. O ç nunca começa uma palavra.

### Cubra e escreva {w="maca" model="maçã"}

### Cubra e escreva {w="coracao" model="coração"}

c ou ç? on:chip[ ]{style="hueco"}a · po:chip[ ]{style="hueco"}o · cabe:chip[ ]{style="hueco"}a · a:chip[ ]{style="hueco"}úcar

:::callout{type="recuerda" title="Lembre-se"}
Antes de **e** e de **i** não se usa cedilha: cebola, cinema.
:::

# O nh e o lh {kicker="Lição 5" letras="nh lh" pic="spider"}

Duas letras juntas podem fazer um som só. O **nh** está em aranha, ninho e banho; o **lh** está em abelha, folha e milho. Ligue as duas letras.

### Cubra e escreva {w="aranha" model="aranha"}

### Cubra e escreva {w="abelha" model="abelha"}

nh ou lh? ni:chip[ ]{style="hueco"}o · ove:chip[ ]{style="hueco"}a · coe:chip[ ]{style="hueco"}o · gali:chip[ ]{style="hueco"}a

:::callout{type="recuerda" title="Lembre-se"}
O **h** é uma letra alta: a laçada dele chega até a linha de cima.
:::

# O ch e o x {kicker="Lição 6" letras="ch x" pic="key"}

O **ch** e o **x** podem ter o mesmo som, como em **chave** e **xícara**. Por isso cada palavra se aprende olhando bem: chuva, chá, bicho; xale, peixe, caixa.

### Cubra e escreva {w="chave" model="chave"}

### Cubra e escreva {w="xicara" model="xícara"}

ch ou x? :chip[ ]{style="hueco"}uva · pei:chip[ ]{style="hueco"}e · bi:chip[ ]{style="hueco"}o · cai:chip[ ]{style="hueco"}a

:::callout{type="recuerda" title="Lembre-se"}
Depois de **ai** e de **ei** se escreve **x**: caixa, peixe, deixe.
:::

# O rr, o ss e os acentos {kicker="Lição 7" letras="rr ss" pic="bird"}

Entre duas vogais, **rr** e **ss** fazem o som forte: carro, pássaro. Com um **r** ou um **s** só, o som fica fraco: caro, casa. O **acento** mostra a sílaba mais forte: café, avó, pássaro.

### Cubra e escreva {w="carro" model="carro"}

### Cubra e escreva {w="passaro" model="pássaro"}

r, rr, s ou ss? te:chip[ ]{style="hueco"}a · ga:chip[ ]{style="hueco"}afa · o:chip[ ]{style="hueco"}o · me:chip[ ]{style="hueco"}a

:::callout{type="recuerda" title="Lembre-se"}
Olhe bem o acento: **avó** é a vovó e **avô** é o vovô.
:::

# Minhas palavras {kicker="Dicionário ilustrado" letras="abc" pic="house"}

Leia cada palavra e copie na linha de baixo com a sua letra mais bonita.

## sol, lua, gato, peixe {p1="sun" w1="sol" p2="moon" w2="lua" p3="cat" w3="gato" p4="fish" w4="peixe"}

## casa, barco, pato, chave {p1="house" w1="casa" p2="boat" w2="barco" p3="duck" w3="pato" p4="key" w4="chave"}

## sapato, maçã, abelha, árvore {p1="shoe" w1="sapato" p2="apple" w2="maçã" p3="bee" w3="abelha" p4="tree" w4="árvore"}

# Copio frases {kicker="Lição 8" letras="Aa" pic="butterfly"}

Uma frase começa com letra maiúscula e termina com ponto final. Deixe entre uma palavra e outra o espaço de um o.

#### Copie a frase {w="frase-1" model="Meu gato dorme ao sol."}

#### Copie a frase {w="frase-2" model="A lua brilha à noite."}

#### Copie a frase {w="frase-3" model="Eu gosto de escrever."}

# Já sei escrever! {style="diploma" texto="Você treinou as vogais, as sílabas, o til, a cedilha, o nh e o lh, o ch e o x, o rr e o ss. Agora você já pode escrever as suas próprias palavras." nombre="Nome" fecha="Data"}
`; // content.<lang>.md, inlined by the Cookbook

// #region art: the edition's ruling drawn in code, the dots from the face's own outlines
// Each country's paper, in x-heights (u) above and below the baseline. lines: [height,
// weight] pairs; band: a filled band; seyes: the French grid of 1 u squares, a heavy line
// every 4 u, verticals every 4 u; Seyès and the Italian page rule a red margin where the
// writing starts.
function geometry(style, u) {
  const R = {
    pauta: { above: 2, below: 1, gap: 1, lines: [[-1, 0.4], [0, 0.9], [1, 0.9], [2, 0.4]] },
    gb: { above: 2, below: 1, gap: 0.8,
      lines: [[-0.8, 0.5], [0, 0.9], [1, 0.5, 'dash'], [1.8, 0.5]] },
    lineatur: { above: 2, below: 1, gap: 1, lines: [[-1, 0.6], [0, 0.6], [1, 0.6], [2, 0.6]],
      band: [0, 1, '#fdf3c7'] },
    righe: { above: 2, below: 1, gap: 1, lines: [[-1, 0.4], [0, 0.8], [1, 0.8], [2, 0.4]],
      margin: true },
    caligrafia: { above: 2.4, below: 1.4, gap: 0.8, lines: [[-1.3, 0.4], [0, 0.9], [1, 0.9],
      [2.3, 0.4]], band: [0, 1, '#e8f0fb'] },
    satr: { above: 2, below: 1, gap: 1, lines: [[-1, 0.4], [0, 0.9], [1, 0.5, 'dash'], [2, 0.4]] },
    seyes: { above: 4, below: 2, gap: -2, seyes: true }, // a row on every heavy line
    sixian: { above: 2, below: 1, gap: 1, lines: [[-1, 0.6], [0, 0.9], [1, 0.6], [2, 0.6]] },
  }[style];
  const pitch = (R.above + R.below + R.gap) * u;
  const base = [0, 1, 2, 3].map((n) => n * pitch + R.above * u);
  // The faces set their x-height at half the em, Playpen Sans Arabic its tooth at 0.4.
  const xh = { satr: 0.4, sixian: 0.508 }[style] ?? 0.5; // Andika's x-height for pinyin
  // line: a tall box for the models, whose clip falls 2 u under the baseline.
  return { ...R, u, pitch, base, size: u / xh, line: u * 10,
    height: (rows) => (rows - 1) * pitch + (R.above + R.below) * u };
}
const n2 = (v) => +v.toFixed(2);
function ruling(g, rows) {
  const out = [];
  const h = g.height(rows);
  const hline = (y, w, dash) => out.push(`<path d="M0 ${n2(y)}H${W}" stroke="${palette.rule}" `
    + `stroke-width="${n2(w * 0.3528)}" stroke-opacity="${w < 0.6 ? 0.55 : 1}"`
    + `${dash ? ' stroke-dasharray="1.2 1"' : ''}/>`);
  if (g.seyes) {
    for (let k = 0; k <= h / g.u + 1e-6; k++) hline(k * g.u, k % 4 === 0 ? 0.9 : 0.35);
    for (let x = 4 * g.u; x <= W; x += 4 * g.u) out.push(`<path d="M${n2(x)} 0V${n2(h)}" `
      + `stroke="${palette.rule}" stroke-width=".12"/>`);
    out.push(`<path d="M.2 0V${n2(h)}" stroke="#d9534f" stroke-width=".3"/>`);
    return out.join('');
  }
  for (const b of g.base.slice(0, rows)) {
    if (g.band) out.push(`<rect x="0" y="${n2(b - g.band[1] * g.u)}" width="${W}" `
      + `height="${n2((g.band[1] - g.band[0]) * g.u)}" fill="${g.band[2]}"/>`);
    for (const [k, w, dash] of g.lines) hline(b - k * g.u, w, dash);
  }
  if (g.margin) out.push(`<path d="M.2 0V${n2(h)}" stroke="#d9534f" stroke-width=".3"/>`);
  return out.join('');
}
// The dots of a word: TRACES holds, for each model, the dots along the outlines of the face's
// thin cut (one row of dots, the two sides of a stroke merged) as a path of zero-length,
// round-capped segments, its advance, and the model's advance in the regular cut, all in mm.
function dotted(word, x, y) {
  const t = TRACES.words[word];
  return `<g transform="translate(${n2(x)} ${n2(y)})"><path d="${t.d}" stroke="${palette.dots}" `
    + `stroke-width="${TRACES.dot}" stroke-linecap="round" fill="none"/>`
    + (t.f ? `<path d="${t.f}" fill="${palette.dots}"/>` : '') + '</g>';
}
// Warm-up strokes: curves drawn by code, dotted at the same pitch as the letters.
const PATTERNS = { // s runs along the stroke; x and y in 2 u, from the baseline up
  lines: (s) => [Math.floor(s) * 0.5, s % 1], // sticks, each drawn from the foot up
  waves: (s) => [s * 0.5, (1 - Math.cos(s * Math.PI)) / 4], // waves in the x-height band
  loops: (s) => [s * 0.5 - 0.2 * Math.sin(2 * Math.PI * s), (1 - Math.cos(2 * Math.PI * s)) / 2],
};
function pattern(name, x0, x1, base, u) {
  const f = PATTERNS[name]; const pts = [];
  let prev = null; let acc = 0;
  for (let s = 0; s < 400; s += 0.002) {
    const [px, py] = f(s); const p = [x0 + px * u * 2, base - py * u * 2];
    if (p[0] > x1) break;
    acc += prev ? Math.hypot(p[0] - prev[0], p[1] - prev[1]) : TRACES.pitch;
    prev = p;
    if (acc < TRACES.pitch) continue;
    pts.push(`M${n2(RTL ? W - p[0] : p[0])} ${n2(p[1])}h.01`); acc = 0;
  }
  return `<path d="${pts.join('')}" stroke="${palette.dots}" stroke-width="${TRACES.dot}" `
    + 'stroke-linecap="round" fill="none"/>';
}
// One block's picture: the ruling, then the dotted copies laid out from the start side. A word
// (###): copies after the model, a row of copies, one copy after the model, an empty row. A
// sentence (####): one copy under the model, then an empty row. A warm-up pattern: two rows
// of it and the start of a third.
function traceSvg(g, w, word, sentence) {
  const rows = sentence ? 3 : 4; const gap = 3 * g.u; const parts = [ruling(g, rows)];
  const copies = (row, from, count = 99) => {
    const t = TRACES.words[word];
    for (let x = from, k = 0; x + t.a <= W && k < count; x += t.a + gap, k++) {
      parts.push(dotted(word, RTL ? W - x - t.a : x, g.base[row]));
    }
  };
  if (PATTERNS[w]) {
    [W, W, W * 0.4].forEach((end, row) => parts.push(pattern(w, 2, end - 2, g.base[row], g.u)));
  } else if (sentence) copies(1, 0, 1);
  else {
    const lead = TRACES.words[word].m + gap;
    copies(0, lead); copies(1, 0); copies(2, lead, 1);
  }
  const h = g.height(rows);
  return `<svg xmlns="http://www.w3.org/2000/svg" width="${W * 10}" height="${n2(h * 10)}" `
    + `viewBox="0 0 ${W} ${n2(h)}">${parts.join('')}</svg>`;
}
// The pictures the practice blocks name: one per block, read off the headings that ask for one,
// or the edition's squares and its pinyin lines.
async function practicePictures(add) {
  const svg = (w, h, body) => `<svg xmlns="http://www.w3.org/2000/svg" width="${W * 10}" `
    + `height="${n2(h * 10)}" viewBox="0 0 ${w} ${n2(h)}">${body}</svg>`;
  const blocks = CJK ? [] : markdown.matchAll(/^(#{3,4}) .*?w="([^"]+)"(?: model="([^"]+)")?/gm);
  for (const [, level, w, word] of blocks) {
    await loadSvg(`trazo-${w}.svg`, traceSvg(G, w, word ?? '', level === '####'));
    add(`trazo-${w}`, `trazo-${w}.svg`, 'svg', W * 10, G.height(level === '####' ? 3 : 4) * 10);
  }
  if (P) {
    await loadSvg('sixian.svg', svg(W, P.height(3), ruling(P, 3)));
    add('sixian', 'sixian.svg', 'svg', W * 10, P.height(3) * 10);
  }
  if (CJK) for (const rows of [3, 4]) {
    await loadSvg(`squares-${rows}.svg`, squaresSvg(rows));
    add(`squares-${rows}`, `squares-${rows}.svg`, 'svg', SQUARES * CELL * 10, rows * CELL * 10);
  }
}
// The squares: 田字格 in red with a dashed cross, or マス with a dotted cross in grey-blue.
function squaresSvg(rows) {
  const c = CELL; const n = SQUARES; const red = ED.ruling === 'tian';
  const ink = red ? '#d0574b' : palette.rule;
  const cross = Array.from({ length: rows }, (_, r) => Array.from({ length: n }, (_, k) =>
    `M${k * c + c / 2} ${r * c + 0.6}V${r * c + c - 0.6}M${k * c + 0.6} ${r * c + c / 2}`
    + `H${k * c + c - 0.6}`).join('')).join('');
  const grid = Array.from({ length: n + 1 }, (_, k) => `M${k * c} 0V${rows * c}`).join('')
    + Array.from({ length: rows + 1 }, (_, r) => `M0 ${r * c}H${n * c}`).join('');
  return `<svg xmlns="http://www.w3.org/2000/svg" width="${n * c * 10}" height="${rows * c * 10}" `
    + `viewBox="0 0 ${n * c} ${rows * c}"><path d="${cross}" fill="none" stroke="${ink}" `
    + `stroke-opacity=".55" stroke-width=".2" stroke-dasharray="${red ? '.9 .6' : '.25 .55'}"/>`
    + `<path d="${grid}" fill="none" stroke="${ink}" stroke-width=".35"/></svg>`;
}
// #endregion


// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = {
  Andika: ['400', '700'], // the text: drawn for children learning to read
  Lexend: ['400', '600', '700'], // labels, kickers, folios
  // The school models, one per country: Google's Playwrite families follow each one.
  'Playwrite GB J': ['400'], 'Playwrite ES': ['400'], 'Playwrite FR Trad': ['400'],
  'Playwrite DE VA': ['400'], 'Playwrite IT Trad': ['400'], 'Playwrite BR': ['400'],
  'LXGW WenKai TC': ['400'], // 楷: the Chinese titles and squares
  'Noto Serif SC': ['400', '700'], // 宋: the Chinese text
  'Noto Sans SC': ['400', '700'], // 黑: Chinese labels
  'Klee One': ['400'], // 教科書体: the Japanese text and its squares
  'Zen Maru Gothic': ['400', '700'], // Japanese labels
  'Playpen Sans Arabic': ['400'], // the Arabic model
  'Noto Naskh Arabic': ['400', '700'], // the Arabic text, vocalised
  'Baloo Bhaijaan 2': ['400', '600', '700'], // Arabic labels
};

// ─── 4 · Build & show ───────────────────────────────────────────────────────
// The edition loads its own faces only: its school face, its text and its labels.
const used = [HAND, TEXT, LABEL, ED.pinyin];
for (const family of Object.keys(FONTS)) if (!used.includes(family)) delete FONTS[family];
await loadFonts(FONTS, markdown);
await loadCjkFonts(FONTS, markdown);
await loadArabicFonts(FONTS, markdown);
const TRACES = CJK ? null : await (await fetch({
  en: asset('traces-en.json'), es: asset('traces-es.json'), ca: asset('traces-ca.json'),
  fr: asset('traces-fr.json'), de: asset('traces-de.json'), it: asset('traces-it.json'),
  pt: asset('traces-pt.json'), ar: asset('traces-ar.json') }[LANG])).json();
const resources = []; // every picture, painted or drawn
const add = (id, fileId, kind, width, height, more = {}) => resources.push({ id, kind,
  typeId: 'dibujo', createdAt: 0, updatedAt: 0, [kind]: { fileId, width, height, ...more } });
// The paintings the edition names (pic="…", p1="…"), from one shared set, at their pixels.
const named = new Set(['medal',
  ...[...markdown.matchAll(/\b(?:pic|p\d)="(\w+)"/g)].map((m) => m[1])]);
await Promise.all([['cover', 'cover-1600.jpg', 1600, 1356],
  ...[...named].map((id) => [id, `${id}-480.jpg`, 480, 480])].map(async ([id, file, w, h]) => {
  await loadImage(file, asset(file)); add(id, file, 'bitmap', w, h, { format: 'jpeg' });
}));
await practicePictures(add); // the rulings, the dots and the squares (#region art)
const doc = await withLoadedFonts(() => buildDocument({ markdown, resources }, config),
  { ...kitFonts(FONTS), text: markdown });
showBook(doc, { title: t({ en: 'Handwriting workbook', es: 'Cuaderno de caligrafía',
  ca: 'Quadern de cal·ligrafia', fr: 'Cahier d’écriture', de: 'Schreibheft',
  it: 'Quaderno di scrittura', pt: 'Caderno de caligrafia', zh: '写字练习册',
  ja: 'かきかたれんしゅうちょう', ar: 'كراسة الخط' }) });
offerPdf(() => renderToPdf(doc, { resourceBytes: imageBytes,
  fontProvider: { zh: cjkPdfProvider, ja: cjkPdfProvider, ar: arabicPdfProvider }[LANG]
    ?? fontsourceProvider }), `${RECIPE}-${LANG}.pdf`);

Kit · core, fonts, viewer, pdf, images, cjk, arabic: igual em todas as receitas · 613 linhas
// ─── 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 v3 ── the same in every recipe · postext.dev/cookbook
// Postext loads the faces a config asks for before layout (prepareFonts,
// buildDocumentWithFonts) and asks the kit for the files: Fontsource's, the
// files the PDF embeds too.

/** The options of buildDocumentWithFonts / prepareFonts / withLoadedFonts:
 *  the Fontsource resolver, and the faces of FONTS loaded with the ones the
 *  config names. FONTS = { 'Family Name': ['400', '400i', '700'] }. */
function kitFonts(FONTS = {}) {
  const faces = Object.entries(FONTS).flatMap(([family, specs]) => specs.map((spec) =>
    ({ family, weight: parseInt(spec, 10), style: spec.endsWith('i') ? 'italic' : 'normal' })));
  return { resolve: fontsourceResolver, faces };
}

/** A face's Fontsource files, in a fixed order: latin, then latin-ext and greek
 *  when `text` needs them and the family ships them (kitSubsetsFor), each with
 *  its unicode-range. Null for a weight or slant Fontsource does not ship. */
async function fontsourceResolver(family, weight, style, { text = '' } = {}) {
  const id = fontsourceId(family);
  const meta = await fontsourceMeta(family);
  if (meta && !(meta.weights.includes(weight) && meta.styles.includes(style))) return null;
  kitStatus('Loading fonts…');
  const at = await fontsourceAt(id);
  return ['latin', ...kitSubsetsFor(text, meta)].map((subset) => ({
    source: `${at}files/${id}-${subset}-${weight}-${style}.woff2`,
    unicodeRange: kitRanges()[subset],
  }));
}

/** The unicode-range of each Fontsource file the kit loads (a function: the
 *  kit is inlined after the pen's code, which runs before a const would be set). */
function kitRanges() {
  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',
  };
}

/** For the cjk, arabic and comics blocks, which add their own files: the
 *  faces of `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.
 *  The files are added once all have loaded, in the order asked (latin, then
 *  latin-ext, then greek), whatever order they arrive in: the last one added
 *  wins a character two files hold. Resolves to the number of faces added. */
async function loadFonts(faces, text = '', { optional = false } = {}) {
  kitStatus('Loading fonts…');
  const ranges = kitRanges();
  const jobs = [];
  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 at = fontsourceAt(id);
    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 = `${await at}files/${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().catch(() => {
          if (subset === 'latin' && !optional) throw new Error(`Fontsource has no ${family} ${weight} ${style}`);
        }));
      }
    }
  }
  const ready = await Promise.all(jobs).catch((error) => { kitFail(error); throw error; });
  return ready.filter((face) => face && document.fonts.add(face)).length;
}

/** 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, '-'); }

/** A package's folder at the one version @5 names now (#766). */
function fontsourceAt(id, u = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@`) {
  return (fontsourceAt.c ??= {})[id] ??= fetch(u + '5/package.json').then((r) => r.json())
    .then((p) => p.version || 5, () => 5).then((v) => `${u}${v}/`);
}

/** 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 v2 ── 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. Other options go to renderPageToCanvas. */
function showPages(docs, { title, width = 460, ...render } = {}) {
  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, { ...render, 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 v3 ── the same in every recipe that exports a PDF
/** The Fontsource files the screen used, as TrueType, with their range and
 *  place: the nearest weight the family ships, upright with no italic;
 *  latin, then what its 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 files = await Promise.all(['latin', ...kitSubsetsFor(text, meta)].map(async (subset, order) => {
    const res = await fetch(`${await fontsourceAt(id)}files/${id}-${subset}-${w}-${s}.woff2`);
    if (!res.ok) throw new Error(`Fontsource has no ${family} ${w} ${s} ${subset}`);
    return Object.assign(await decompressWoff2(new Uint8Array(await res.arrayBuffer())),
      { unicodeRange: kitRanges()[subset], order });
  }));
  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 v3 ── 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 as a vector image, its fonts inside (inlineSvgFonts, ≥ 1.25).
 *  `options` go to registerResourceImage: { singleInk: true } tints it on the canvas. */
async function loadSvg(fileId, svg, options) {
  if (typeof inlineSvgFonts === 'function') svg = await inlineSvgFonts(svg, svgFaces);
  const img = new Image();
  img.src = `data:image/svg+xml;charset=utf-8,${encodeURIComponent(svg)}`;
  await img.decode();
  registerResourceImage(fileId, img, options);
  (loadImage.bytes ??= new Map()).set(fileId, new TextEncoder().encode(svg));
}

/** A face's Fontsource files: nearest weight; latin + what the SVG sets. */
async function svgFaces(family, weight, style, { codePoints = [] } = {}) {
  const [id, m] = [fontsourceId(family), await fontsourceMeta(family)];
  const w = m?.weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a)) ?? weight;
  const s = m?.styles.includes(style) === false ? 'normal' : style;
  return Promise.all(['latin', ...kitSubsetsFor(String.fromCodePoint(...codePoints), m)].map(async (x) => new Uint8Array(
    await (await fetch(`${await fontsourceAt(id)}files/${id}-${x}-${w}-${s}.woff2`)).arrayBuffer())));
}

/** 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 v2 ── 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 = `${id}/${weight}${style === 'italic' ? '-italic' : ''}.css`;
  if (!cjkSlices.cache.has(css)) {
    let at;
    cjkSlices.cache.set(css, fontsourceAt(id).then((a) => fetch(at = a + css.slice(id.length + 1)))
      .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], at).href, range, ranges };
      }).reverse()));
  }
  return cjkSlices.cache.get(css);
}

/** The file of `slices` the screen sets code point `cp` in, if any: the
 *  last one loadCjkFonts adds whose range holds it. A numbered file that
 *  repeats a letter of latin is added after latin, and wins it. */
function cjkSliceFor(slices, cp) {
  const holds = (slice) => slice.ranges.some(([lo, hi]) => cp >= lo && cp <= hi);
  return slices.reduce((last, slice) => (holds(slice) ? slice : last), undefined);
}

/** 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 the engine's later round
 *  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 the
 *  screen set its pages' characters in (`request.codePoints`), each marked
 *  with its unicode-range and its place in the order loadCjkFonts added
 *  them: postext-pdf sets a character two files hold in the one added
 *  last, as the browser does. 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.map(async (slice, order) => {
    if (!picked.has(slice)) return null;
    const res = await fetch(slice.url);
    if (!res.ok) throw new Error(`Fontsource file ${slice.url} (${res.status})`);
    const bytes = await decompressWoff2(new Uint8Array(await res.arrayBuffer()));
    return Object.assign(bytes, { unicodeRange: slice.range, order });
  })).then((files) => files.filter(Boolean));
}

/** 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, each marked with its unicode-range and its place in that order:
 *  the PDF sets a character in the file the browser took it from. 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 = `${await fontsourceAt(id)}files/${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)]);
  const ranges = kitRanges();
  return ext ? [Object.assign(latin, { unicodeRange: ranges.latin, order: 0 }),
    Object.assign(ext, { unicodeRange: ranges['latin-ext'], order: 1 })] : 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 v2 ── 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. */
async function arabicFileUrl(family, weight, style) {
  const id = fontsourceId(family);
  return `${await fontsourceAt(id)}files/${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 the engine's later round 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 ${outside.slice(0, 12).join(' ')}`);
    for (const [family, specs] of Object.entries(faces)) {
      if (!(await isArabicFamily(family))) continue;
      for (const spec of new Set(specs)) {
        const weight = parseInt(spec, 10);
        const style = spec.endsWith('i') ? 'italic' : 'normal';
        const face = new FontFace(family, `url(${await 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), each marked with its
 *  unicode-range and its place in the order the screen added them (latin
 *  and latin-ext by loadFonts, then arabic): the arabic file also has a
 *  space and brackets, which the browser takes from latin, the file whose
 *  range holds them, and postext-pdf follows it. 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 subsets = !wanted.length || wanted.some(inArabicRange) ? ['arabic', 'latin'] : ['latin'];
  if (meta.subsets.includes('latin-ext') && wanted.some((cp) => /[Ā-˿Ḁ-ỿ]/u.test(String.fromCodePoint(cp)))) {
    subsets.push('latin-ext');
  }
  const at = await fontsourceAt(id);
  return Promise.all(subsets.map(async (subset) => {
    const url = `${at}files/${id}-${subset}-${w}-${s}.woff2`;
    const res = await fetch(url);
    if (!res.ok) throw new Error(`Fontsource file ${url} (${res.status})`);
    const bytes = await decompressWoff2(new Uint8Array(await res.arrayBuffer()));
    return Object.assign(bytes, { unicodeRange: subset === 'arabic' ? arabicRange() : kitRanges()[subset],
      order: ['latin', 'latin-ext', 'greek', 'arabic'].indexOf(subset) });
  }));
}

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