# Un cuaderno de ejercicios chino, del alumno y del profesor

> Un 练习册 de lengua y matemáticas: apartados 一、二、, paréntesis （　）, 田字格 y cuentas en vertical, compuesto dos veces con un solo texto, para el alumno y el profesor.

- Versión HTML: https://postext.dev/es/cookbook/chinese-exercise-book
- Receta N.º 171 · Libros de texto · Nivel 2 (Intermedio) · Salidas: Canvas, PDF
- Géneros: Cuadernos y ejercicios, Libros de texto
- Requiere postext ≥ 1.59.0, postext-pdf ≥ 1.59.0 · probada con 1.59.0, postext-pdf 1.59.0 el 2026-10-24
- Páginas: [1](https://postext.dev/cookbook/chinese-exercise-book/zh/p01.webp?v=0914fd07), [2](https://postext.dev/cookbook/chinese-exercise-book/zh/p02.webp?v=0914fd07), [3](https://postext.dev/cookbook/chinese-exercise-book/zh/p03.webp?v=0914fd07), [4](https://postext.dev/cookbook/chinese-exercise-book/zh/p04.webp?v=0914fd07), [1](https://postext.dev/cookbook/chinese-exercise-book/zh/p05.webp?v=0914fd07), [2](https://postext.dev/cookbook/chinese-exercise-book/zh/p06.webp?v=0914fd07), [3](https://postext.dev/cookbook/chinese-exercise-book/zh/p07.webp?v=0914fd07), [4](https://postext.dev/cookbook/chinese-exercise-book/zh/p08.webp?v=0914fd07)
- Abrir en el Sandbox: https://postext.dev/es/sandbox#recipe=chinese-exercise-book&lang=zh (.postext: https://postext.dev/cookbook/chinese-exercise-book/zh/chinese-exercise-book.postext)
- Última actualización: 2026-10-24
- Otros idiomas: [en](https://postext.dev/en/cookbook/chinese-exercise-book.md), [ca](https://postext.dev/ca/cookbook/chinese-exercise-book.md), [de](https://postext.dev/de/cookbook/chinese-exercise-book.md), [fr](https://postext.dev/fr/cookbook/chinese-exercise-book.md), [it](https://postext.dev/it/cookbook/chinese-exercise-book.md), [pt](https://postext.dev/pt/cookbook/chinese-exercise-book.md), [zh](https://postext.dev/zh/cookbook/chinese-exercise-book.md), [ja](https://postext.dev/ja/cookbook/chinese-exercise-book.md), [ar](https://postext.dev/ar/cookbook/chinese-exercise-book.md)

## En pocas palabras

Un cuaderno de ejercicios de primaria chino: dos unidades de lengua y de matemáticas. El mismo texto da el ejemplar del alumno, con huecos y soluciones al final, y el del profesor, con cada respuesta en rojo en su sitio.

## Lo que vas a componer

Dos unidades de un 练习册 de segundo de primaria en formato 16开: una de lengua, 春天来了, y otra de matemáticas sobre sumas y restas hasta cien. Cada una abre con una franja de acuarela, una pestaña con la asignatura y una línea para la clase, el nombre y la nota, y sigue con los apartados que imprime un cuaderno chino: 看拼音写词语, lecturas que rodear, 选择题 con un （　） tras el enunciado y A. B. C. D. en fila, 判断题 con un paréntesis al final de la línea, huecos, 连线 entre clasificadores y cosas, una frase que escribir en 田字格, 口算 en cuatro columnas, 竖式 con una casilla por cifra y un problema. Los puntos van en cada enunciado, como los lee el alumno. El mismo Markdown se compone dos veces: el libro del alumno, con el 参考答案 al final de cada unidad, y el del profesor, con cada respuesta escrita en rojo, en letra Kai, en su sitio.

**Esta receta responde a:**

- ¿Cómo compongo preguntas chinas con un （　） tras el enunciado y las opciones A. B. C. D. en fila?
- ¿Cómo saco la edición del profesor, con las respuestas impresas en su sitio, del mismo libro del alumno?
- ¿Cómo doy a una pregunta abierta pauta Seyès francesa, cuadrícula o cuadros 田字格 para escribir?
- ¿Cómo compongo la división larga tal como la escriben las escuelas de cada país?

## La respuesta corta

```js
// script.js, líneas 36–65
// The exercise style is the form; the Markdown holds every word, the points included. The
// same text builds both editions: `edition: 'teacher'` writes each answer into its blank,
// bracket and square in red Kai, rings the right options and draws the matching lines.
const lianxi = {
  id: 'lianxi',
  number: { format: 'simp-chinese-informal', suffix: '、', fontFamily: HEI, color: col('green') },
  instruction: { fontFamily: HEI, bold: false }, // 黑体, not bold: the points stay quiet
  // 选择题: A. B. C. D. in a row, a （　） after the stem for the letter.
  options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
  trueFalse: { look: 'bracket' }, // 判断题: （　） at the end of the line, √ or ×
  blank: { look: 'line', color: col('ink') },
  area: { kind: 'tianzige', color: col('rule') }, // 写话 on 田字格
  match: { color: col('green') },
  grid: { fontFamily: SONG, rule: col('rule') },
  answers: { color: col('red'), fontFamily: KAI },
  solutions: { box: 'daan' },
  marginTop: em(1.2), marginBottom: em(0.6),
};
const exerciseStyles = [
  lianxi,
  // 看拼音写词语: a box under each syllable, as wide as its word.
  { id: 'pinyin', extends: 'lianxi', blank: { look: 'box', width: 'answer', color: col('rule') } },
  // 在（　）里填: the bracket is in the text, the blank inside it draws nothing.
  { id: 'kuohao', extends: 'lianxi', blank: { look: 'none', width: 'answer' } },
];
let edition = 'student'; // the second build below prints the teacher's book
// The pupil's book: 参考答案 where a :::solutions line stands, at the end of each unit.
// The teacher's book: every answer on the page, so no key at the end.
const exercises = () => ({ edition,
  solutions: { placement: edition === 'teacher' ? 'none' : 'directive' } });
```

## Ingredientes

**Enseña**

- [Estilos de ejercicio](https://postext.dev/es/docs/exercises.md#estilos-de-ejercicio): exerciseStyles: cómo se imprime una familia de ejercicios: el número (disco, cuadrado, rótulo), el enunciado, las letras de las opciones, los huecos, las casillas de V/F, los puntos para unir, el banco de palabras, las zonas de escritura, las cuadrículas, los iconos de actividad y la dificultad.
- [Edición del profesor](https://postext.dev/es/docs/exercises.md#edición-del-profesor): exercises.edition: 'teacher' imprime cada respuesta en su sitio en un segundo color, rodea las opciones correctas y traza las líneas de unir: el libro del profesor a partir del texto del alumno.
- [Elección y verdadero o falso](https://postext.dev/es/docs/exercises.md#opción-múltiple-y-verdadero-o-falso): Opción múltiple a partir de una lista de tareas (- [x] correcta, - [ ] incorrecta), con letras a) b) c), A. B. C., ア イ ウ o أ ب ج y una casilla, un círculo o un paréntesis para contestar; afirmaciones de verdadero o falso con las letras del idioma: V F, R F, √ × u ○ ×.

**También usa**

- [Ejercicios](https://postext.dev/es/docs/exercises.md#ejercicios)
- [Huecos y bancos de palabras](https://postext.dev/es/docs/exercises.md#huecos-y-banco-de-palabras)
- [Unir y clasificar](https://postext.dev/es/docs/exercises.md#relacionar-y-clasificar)
- [Preguntas abiertas y zonas de escritura](https://postext.dev/es/docs/exercises.md#preguntas-abiertas-y-espacio-para-escribir)
- [Operaciones en columna](https://postext.dev/es/docs/exercises.md#operaciones-en-vertical)
- [Soluciones](https://postext.dev/es/docs/exercises.md#soluciones)
- [Numeración china](https://postext.dev/es/docs/configuration-page-layout.md#numeración)
- [Fuentes chinas, japonesas y coreanas](https://postext.dev/es/docs/configuration-pdf-output.md#fuentes-chinas-japonesas-y-coreanas)
- [Retícula de caracteres](https://postext.dev/es/docs/configuration-east-asian.md#retícula-de-caracteres)
- [Puntos de énfasis y líneas de nombre y de título](https://postext.dev/es/docs/document-format-inline.md#marcas-chinas-ruby-y-warichu)
- [Chips en línea](https://postext.dev/es/docs/configuration-styles.md#estilos-de-chip)
- [Tres o más columnas](https://postext.dev/es/docs/configuration-page-layout.md#tipos-de-disposición)
- [Aperturas diseñadas](https://postext.dev/es/docs/configuration-headings.md#apertura-a-toda-página-y-diseño-avanzado)
- [Atributos de título](https://postext.dev/es/docs/document-format.md#atributos-de-encabezado)
- [Imágenes en los diseños de página](https://postext.dev/es/docs/configuration-headers-footers.md#elementos-de-imagen)
- [Paleta de color semántica](https://postext.dev/es/docs/configuration-fonts-colors-viewers.md#paleta-de-colores)
- [Exportación a PDF](https://postext.dev/es/docs/configuration-pdf-output.md#generación-de-pdf)
- [Columnas en un recuadro o en el texto](https://postext.dev/es/docs/document-format-directives.md#columns)
- [Recuadros que se parten o no](https://postext.dev/es/docs/configuration-callouts.md#el-contenedor-callout)
- [Corte de líneas en chino](https://postext.dev/es/docs/configuration-east-asian.md#tipografía-de-asia-oriental)
- [Equilibrado de columnas](https://postext.dev/es/docs/configuration-page-flow.md#equilibrado-de-columnas)
- [Estilos de párrafo](https://postext.dev/es/docs/configuration-styles.md#estilos-de-párrafo)
- [Fuentes incrustadas en el PDF](https://postext.dev/es/docs/configuration-pdf-output.md#por-qué-un-proveedor-de-fuentes)
- [Figuras y tablas como recursos](https://postext.dev/es/docs/document-format-resources.md#recursos)

**La configuración de un vistazo**

- [`bodyText`](https://postext.dev/es/docs/configuration-text.md#texto-base), [`calloutStyles`](https://postext.dev/es/docs/configuration-callouts.md#estilos-de-recuadro), [`chipStyles`](https://postext.dev/es/docs/configuration-styles.md#estilos-de-chip), [`cjk`](https://postext.dev/es/docs/configuration-east-asian.md#tipografía-de-asia-oriental), [`colorPalette`](https://postext.dev/es/docs/configuration-fonts-colors-viewers.md#paleta-de-colores), `exerciseStyles`, `exercises`, [`footer`](https://postext.dev/es/docs/configuration-headers-footers.md#cabeceras-y-pies), [`header`](https://postext.dev/es/docs/configuration-headers-footers.md#cabeceras-y-pies), [`headings`](https://postext.dev/es/docs/configuration-headings.md#encabezados), [`layout`](https://postext.dev/es/docs/configuration-page-layout.md#disposición), [`locale`](https://postext.dev/es/docs/configuration-language.md#separación-silábica), [`orderedLists`](https://postext.dev/es/docs/configuration-lists-math.md#listas-ordenadas), [`page`](https://postext.dev/es/docs/configuration-page-layout.md#página), [`paragraphStyles`](https://postext.dev/es/docs/configuration-styles.md#estilos-de-párrafo)

**API**

- [`buildDocument`](https://postext.dev/es/docs/configuration-programmatic-usage.md#construir-un-documento), [`decompressWoff2`](https://postext.dev/es/docs/configuration-pdf-output.md#proveedor-de-fuentes-en-el-navegador-fontsource--woff2), [`registerResourceImage`](https://postext.dev/es/docs/architecture.md#api-pública), [`renderPageToCanvas`](https://postext.dev/es/docs/configuration-programmatic-usage.md#renderizar-una-página-como-mapa-de-bits), [`renderToPdf`](https://postext.dev/es/docs/configuration-pdf-output.md#generación-de-pdf), [`withLoadedFonts`](https://postext.dev/es/docs/configuration-programmatic-usage.md#cargar-las-fuentes-antes-de-componer)

**Tipografías**

- Noto Serif SC (OFL-1.1), Noto Sans SC (OFL-1.1), LXGW WenKai TC (OFL-1.1)

## Elaboración

### 1 · Un estilo para todos los apartados

El código está en [la respuesta corta](https://postext.dev/es/cookbook/chinese-exercise-book.md#la-respuesta-corta). Los apartados se cuentan con numerales chinos seguidos de un 、 de ancho completo, así que tras el número no va ningún espacio; el enunciado va en la letra Hei sin negrita, para que los puntos entre paréntesis se lean como parte de él. `options.bracket` escribe el （　） tras cada enunciado, y en el libro del profesor la letra correcta entra dentro. Los dos estilos pequeños amplían el principal: `pinyin` dibuja cada hueco como una caja tan ancha como su palabra y `kuohao` no dibuja nada, porque el paréntesis de 在（　）里填 ya está en el texto.

### 2 · El libro del alumno y el del profesor con un solo texto

```js
// script.js, líneas 334–338
const build = () => withLoadedFonts(() => buildDocument({ markdown, resources }, config()),
  { ...kitFonts(FONTS), text: markdown });
const pupil = await build();
edition = 'teacher';
const docs = [pupil, await build()];
```

La configuración es una función, así que cada composición recibe su propio objeto y el paquete del Sandbox guarda el del alumno. `edition: 'teacher'` escribe las respuestas con el color y la letra de `answers`: las palabras en sus casillas, las letras en sus paréntesis, √ y × en los 判断题, las cifras en las casillas del 竖式 y la frase modelo con un carácter por cuadro. El libro del alumno lleva las soluciones donde está la línea `:::solutions`, al final de cada unidad; el del profesor no las necesita.

### 3 · La apertura de unidad con su pintura

```js
// script.js, líneas 69–87
const BAND = 184 / 2.4; // mm: the painting's height at the page's width
const opener = { enabled: true, minHeight: mm(BAND - 22 + 23), slot: { elements: [
  { kind: 'image', id: 'picture', resourceId: '{attr.pic}', decorative: true, reserve: false,
    placement: { anchor: { to: 'page', edge: 'top-left' },
      size: { width: mm(184), height: mm(BAND) } } },
  { kind: 'text', id: 'subject', content: '{attr.kicker}', fontFamily: HEI, fontSize: pt(11),
    fontWeight: 700, color: col('paper'), letterSpacing: pt(2), align: 'center',
    box: { backgroundColor: col('green'), borderRadius: mm(1.5),
      padding: { top: mm(0.8), bottom: mm(0.8), left: mm(2.4), right: mm(2) } },
    placement: { anchor: { to: 'container', edge: 'top-left' },
      offset: { x: mm(0), y: mm(BAND - 22 + 6) } } },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: HEI, fontSize: pt(24),
    fontWeight: 700, color: col('ink'), align: 'left',
    placement: { anchor: { to: '#subject', edge: 'right-of' },
      offset: { x: mm(4), y: mm(-2.6) } } },
  { kind: 'rule', id: 'rule', direction: 'horizontal', thickness: pt(1.2), color: col('green'),
    placement: { anchor: { to: 'container', edge: 'top-left' },
      offset: { x: mm(0), y: mm(BAND - 22 + 19) }, size: { width: 'fill' } } },
] } };
```

La pintura se ancla a la página, así que llega al borde superior tanto en la página impar como en la par; la pestaña y el título se colocan desde el arranque de la caja de texto, bajo el pie de la pintura. Las dos unidades comparten el diseño y solo cambian sus atributos de título, `kicker` y `pic`.

### 4 · Folios al pie

```js
// script.js, líneas 91–101
const foot = (id, content, parity, edge, x, extra = {}) => ({ kind: 'text', id, content,
  parity, fontFamily: HEI, fontSize: pt(8), color: col('muted'),
  placement: { anchor: { to: 'page', edge }, offset: { x: mm(x), y: mm(-10) } }, ...extra });
const footer = { elements: [
  foot('folio-v', '{pageNumber}', 'even', 'bottom-left', 16,
    { fontWeight: 700, color: col('green') }),
  foot('series', '{title}', 'even', 'bottom-left', 24),
  foot('unit', '{chapterTitle}', 'odd', 'bottom-right', -24, { align: 'right' }),
  foot('folio-r', '{pageNumber}', 'odd', 'bottom-right', -16,
    { fontWeight: 700, color: col('green'), align: 'right' }),
] };
```

Los cuadernos chinos llevan el folio al pie. El título de la serie sale de la cabecera YAML del Markdown (`{title}`), y el de la unidad, de su título (`{chapterTitle}`).

## La receta completa

Un solo archivo, compuesto a partir de la carpeta de la receta con el texto de ejemplo y el kit común del Recetario ya incluidos; construye su propia página. Para ejecutarlo, ponlo en un `<script type="module">` de una página vacía o pégalo en el panel JS de un pen nuevo de CodePen (como módulo). Importa postext desde esm.sh, así que no hay nada que instalar ni compilar.

- Carpeta de la receta: https://github.com/drnachio/postext/tree/main/cookbook/chinese-exercise-book

### script.js

```js
// ═══ Postext Cookbook · Nº 171 · A Chinese exercise book, pupil's and teacher's ═══
// https://postext.dev/en/cookbook/chinese-exercise-book
// Code: MIT · Text: original (CC BY 4.0) · Pictures: generated with diffusion models
// Fonts: Noto Serif SC, Noto Sans SC, LXGW WenKai TC (SIL OFL 1.1) · Needs postext ≥ 1.59.0
import {
  buildDocument, withLoadedFonts, renderPageToCanvas, registerResourceImage,
} from 'https://esm.sh/postext';
import { renderToPdf, decompressWoff2 } from 'https://esm.sh/postext-pdf';

const LANG = 'zh'; // @lang: the language of the frame; the exercise book is Chinese in all
const RECIPE = 'chinese-exercise-book';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: a green exercise book, and the red of the teacher's pen
const palette = {
  ink: '#1f2523', // text: a green-tinted near-black
  green: '#2c7350', // the one accent: section numbers, the subject tab, the squares
  red: '#d0352c', // the teacher's answers
  tint: '#e6f2ea', // the subject tab's ground, the answers box
  rule: '#8fb9a2', // 田字格, the matching dots' lines
  muted: '#68736d', // folios, the series line
  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.green, model: 'hex' } },
];
// #endregion
// 宋 for the text, 黑 for the instructions and labels, 楷 for what the teacher writes.
const [SONG, HEI, KAI] = ['Noto Serif SC', 'Noto Sans SC', 'LXGW WenKai TC'];
const CHARS = 40; // characters per line: 40 × 10.5 pt = 148 mm
const SIZE = 10.5; // pt: 五号, the size of a school book's text

// #region answer: sections 一、二、 that print the pupil's book or the teacher's
// The exercise style is the form; the Markdown holds every word, the points included. The
// same text builds both editions: `edition: 'teacher'` writes each answer into its blank,
// bracket and square in red Kai, rings the right options and draws the matching lines.
const lianxi = {
  id: 'lianxi',
  number: { format: 'simp-chinese-informal', suffix: '、', fontFamily: HEI, color: col('green') },
  instruction: { fontFamily: HEI, bold: false }, // 黑体, not bold: the points stay quiet
  // 选择题: A. B. C. D. in a row, a （　） after the stem for the letter.
  options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
  trueFalse: { look: 'bracket' }, // 判断题: （　） at the end of the line, √ or ×
  blank: { look: 'line', color: col('ink') },
  area: { kind: 'tianzige', color: col('rule') }, // 写话 on 田字格
  match: { color: col('green') },
  grid: { fontFamily: SONG, rule: col('rule') },
  answers: { color: col('red'), fontFamily: KAI },
  solutions: { box: 'daan' },
  marginTop: em(1.2), marginBottom: em(0.6),
};
const exerciseStyles = [
  lianxi,
  // 看拼音写词语: a box under each syllable, as wide as its word.
  { id: 'pinyin', extends: 'lianxi', blank: { look: 'box', width: 'answer', color: col('rule') } },
  // 在（　）里填: the bracket is in the text, the blank inside it draws nothing.
  { id: 'kuohao', extends: 'lianxi', blank: { look: 'none', width: 'answer' } },
];
let edition = 'student'; // the second build below prints the teacher's book
// The pupil's book: 参考答案 where a :::solutions line stands, at the end of each unit.
// The teacher's book: every answer on the page, so no key at the end.
const exercises = () => ({ edition,
  solutions: { placement: edition === 'teacher' ? 'none' : 'directive' } });
// #endregion

// #region opener: the unit's painting to the bleed, the subject tab and the title
const BAND = 184 / 2.4; // mm: the painting's height at the page's width
const opener = { enabled: true, minHeight: mm(BAND - 22 + 23), slot: { elements: [
  { kind: 'image', id: 'picture', resourceId: '{attr.pic}', decorative: true, reserve: false,
    placement: { anchor: { to: 'page', edge: 'top-left' },
      size: { width: mm(184), height: mm(BAND) } } },
  { kind: 'text', id: 'subject', content: '{attr.kicker}', fontFamily: HEI, fontSize: pt(11),
    fontWeight: 700, color: col('paper'), letterSpacing: pt(2), align: 'center',
    box: { backgroundColor: col('green'), borderRadius: mm(1.5),
      padding: { top: mm(0.8), bottom: mm(0.8), left: mm(2.4), right: mm(2) } },
    placement: { anchor: { to: 'container', edge: 'top-left' },
      offset: { x: mm(0), y: mm(BAND - 22 + 6) } } },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: HEI, fontSize: pt(24),
    fontWeight: 700, color: col('ink'), align: 'left',
    placement: { anchor: { to: '#subject', edge: 'right-of' },
      offset: { x: mm(4), y: mm(-2.6) } } },
  { kind: 'rule', id: 'rule', direction: 'horizontal', thickness: pt(1.2), color: col('green'),
    placement: { anchor: { to: 'container', edge: 'top-left' },
      offset: { x: mm(0), y: mm(BAND - 22 + 19) }, size: { width: 'fill' } } },
] } };
// #endregion

// #region furniture: folios at the foot, the series line on the verso, the unit on the recto
const foot = (id, content, parity, edge, x, extra = {}) => ({ kind: 'text', id, content,
  parity, fontFamily: HEI, fontSize: pt(8), color: col('muted'),
  placement: { anchor: { to: 'page', edge }, offset: { x: mm(x), y: mm(-10) } }, ...extra });
const footer = { elements: [
  foot('folio-v', '{pageNumber}', 'even', 'bottom-left', 16,
    { fontWeight: 700, color: col('green') }),
  foot('series', '{title}', 'even', 'bottom-left', 24),
  foot('unit', '{chapterTitle}', 'odd', 'bottom-right', -24, { align: 'right' }),
  foot('folio-r', '{pageNumber}', 'odd', 'bottom-right', -16,
    { fontWeight: 700, color: col('green'), align: 'right' }),
] };
// #endregion

const config = () => ({
  locale: 'zh-Hans', // written out: Kaiming punctuation, no hyphenation
  colorPalette,
  page: { sizePreset: 'custom', width: mm(184), height: mm(260), dpi: 150, // 16开
    margins: { top: mm(22), bottom: mm(20), left: mm(18), right: mm(16), mirror: true } },
  layout: { layoutType: 'single' },
  cjk: { grid: { enabled: true, charsPerLine: CHARS, linesPerPage: 29 } },
  bodyText: { fontFamily: SONG, fontSize: pt(SIZE), lineHeight: pt(21), color: col('ink'),
    boldColor: col('ink'), italicColor: col('ink'), referenceColor: col('ink'),
    textAlign: 'justify', firstLineIndent: pt(0), avoidWidows: true, avoidOrphans: true },
  headings: { fontFamily: HEI, color: col('ink'), fontWeight: 700, balancing: { enabled: false },
    levels: [{ level: 1, fontSize: pt(24), breakBefore: { parity: 'any' },
      advancedDesign: opener }] },
  orderedLists: { numberFormat: 'arabic', color: col('ink'), fontWeight: 400 },
  paragraphStyles: [
    // 班级、姓名、得分 at the head of each unit
    { id: 'xinxi', fontFamily: HEI, fontSize: pt(9.5), textAlign: 'right', firstLineIndent: pt(0),
      color: col('muted'), marginBottom: mm(2) },
    { id: 'colophon', fontFamily: HEI, fontSize: pt(7.5), lineHeight: pt(11), color: col('muted'),
      textAlign: 'left', firstLineIndent: pt(0), marginTop: mm(6) },
  ],
  chipStyles: [{ id: 'xian', backgroundEnabled: false, underline: 'solid', borderWidth: pt(0.6),
    borderColor: col('muted'), minWidth: mm(24), paddingX: pt(0), paddingY: pt(0) }],
  calloutStyles: [{ id: 'daan', background: col('tint'), borderRadius: mm(2),
    padding: { top: mm(3), right: mm(4), bottom: mm(3.5), left: mm(4) },
    titleStyle: { fontFamily: HEI, fontSize: pt(11), fontWeight: 700, color: col('green') },
    body: { fontSize: pt(9.5), lineHeight: pt(17), color: col('ink'), firstLineIndent: pt(0) },
    marginTop: mm(6), marginBottom: mm(2), keepTogether: false }],
  exerciseStyles,
  exercises: exercises(),
  header: { elements: [] },
  footer,
});

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
title: "二年级下册　语文数学同步练习"
---

# 第一单元　春天来了 {kicker="语文" pic="spring"}

:::paragraphs{style="xinxi"}
班级:chip[　]{style="xian"}　姓名:chip[　]{style="xian"}　得分:chip[　]{style="xian"}
:::

:::exercise{style=pinyin}
看拼音，写词语。（每词1分，共8分）

:::columns{count=4}
chūn tiān

[[春天]]

liǔ shù

[[柳树]]

xiǎo cǎo

[[小草]]

yàn zi

[[燕子]]

wēn nuǎn

[[温暖]]

huā duǒ

[[花朵]]

zhǒng zi

[[种子]]

tián yě

[[田野]]
:::
:::

:::exercise
用“○”圈出加点字的正确读音。（每题1分，共3分）

:::columns{count=3}
*种*子 [[(zhǒng) | zhòng]]

春*风* [[(fēng) | fēn]]

*发*芽 [[(fā) | fà]]
:::
:::

:::exercise
选择题。把正确答案的序号填在括号里。（每题2分，共4分）

1. “春风吹绿了柳树”中，“吹绿”的意思是
   - [ ] 把柳树涂绿了
   - [x] 使柳树发芽变绿
   - [ ] 把柳树吹弯了
2. 下面哪个词语和“温暖”的意思相近？
   - [ ] 寒冷
   - [ ] 凉快
   - [x] 暖和
   - [ ] 炎热
:::

:::exercise{type=truefalse}
判断对错。对的画“√”，错的画“×”。（每题1分，共3分）

- [x] 燕子是春天从南方飞回来的。
- [ ] “桃花”和“桃子”说的是同一样东西。
- [x] 可以说“一朵花”，也可以说“一朵云”。
:::

:::exercise
按课文内容填空。（每空1分，共4分）

春天来了，小草从地下[[探出]]头来，柳树长出了[[嫩绿]]的新芽。小燕子从[[南方]]飞回来了，田野里到处都是[[花香]]。
:::

:::exercise
连一连，给事物找到合适的量词。（共4分）

- 一朵 -> 桃花
- 一只 -> 燕子
- 一棵 -> 柳树
- 一片 -> 田野
:::

:::exercise{type=open area=tianzige lines=3}
用上“春风”“柳树”“燕子”中的两个词，写一两句话。（4分）

:::solution
春风吹来，柳树发出了嫩绿的新芽。
:::
:::

:::solutions

# 第一单元　100以内的加减法 {kicker="数学" pic="market"}

:::paragraphs{style="xinxi"}
班级:chip[　]{style="xian"}　姓名:chip[　]{style="xian"}　得分:chip[　]{style="xian"}
:::

:::exercise
直接写得数。（每题1分，共8分）

:::columns{count=4}
25 + 37 = [[62]]

90 − 46 = [[44]]

8 × 7 = [[56]]

63 ÷ 9 = [[7]]

48 + 26 = [[74]]

71 − 38 = [[33]]

6 × 9 = [[54]]

42 ÷ 6 = [[7]]
:::
:::

:::exercise{style=kuohao}
在（　）里填上“>”“<”或“=”。（每题1分，共4分）

:::columns{count=4}
45 + 8（[[>]]）50

36 − 9（[[=]]）27

7 × 8（[[<]]）60

81 ÷ 9（[[>]]）8
:::
:::

:::exercise{type=arithmetic}
用竖式计算。（每题3分，共12分）

- 345 + 278
- 902 - 456
- 124 × 3
- 864 ÷ 4
:::

:::exercise{type=open area=lines lines=3}
解决问题。妈妈买了45个橘子，分给邻居18个，还剩多少个？（4分）

:::solution
45 − 18 = 27（个）　答：还剩27个。
:::
:::

:::solutions

:::paragraphs{style="colophon"}
字体：Noto Serif SC、Noto Sans SC、LXGW WenKai TC（SIL OFL）　插图：扩散模型生成　题目为本书原创（CC BY 4.0）
:::
`; // content.zh.md: one text for both editions

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = {
  'Noto Serif SC': ['400', '700'], // 宋: the text, the pinyin
  'Noto Sans SC': ['400', '700'], // 黑: instructions, numbers, titles
  'LXGW WenKai TC': ['400'], // 楷: the teacher's answers
};

// ─── 4 · Build & show ───────────────────────────────────────────────────────
// Each face loads the files of the characters it sets (gotcha: cjk-fonts-slices); the Kai
// sets the answers, so it loads them all.
const answers = [...markdown.matchAll(/\[\[([^\]]+)\]\]/g)].map((m) => m[1]).join('')
  + markdown.split(':::solution').slice(1).join('') + '√×ABCD0123456789';
await loadFonts(FONTS, markdown);
await loadCjkFonts({ [SONG]: FONTS[SONG], [HEI]: FONTS[HEI] }, markdown);
await loadCjkFonts({ [KAI]: FONTS[KAI] }, answers);
const resources = [];
for (const [id, file] of [['spring', 'spring-1600.jpg'], ['market', 'market-1600.jpg']]) {
  await loadImage(file, asset(file));
  resources.push({ id, typeId: 'figure', kind: 'bitmap', createdAt: 0, updatedAt: 0,
    bitmap: { fileId: file, format: 'jpeg', width: 1600, height: 667 } });
}
// #region editions: one text, two books: the pupil's, then the teacher's
const build = () => withLoadedFonts(() => buildDocument({ markdown, resources }, config()),
  { ...kitFonts(FONTS), text: markdown });
const pupil = await build();
edition = 'teacher';
const docs = [pupil, await build()];
// #endregion
showPages(docs, { title: t({ zh: '练习册：学生用书与教师用书', en: 'A Chinese exercise book',
  es: 'Un cuaderno de ejercicios chino' }) });
offerPdf(() => renderToPdf(docs, { fontProvider: cjkPdfProvider, resourceBytes: imageBytes }),
  `${RECIPE}.pdf`);

// ─── 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 and asks the kit
// for Fontsource's files, the ones the PDF embeds too.

/** buildDocumentWithFonts' options: the resolver, and FONTS' faces loaded
 *  with the config's. 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 files with their ranges: latin, then latin-ext and greek when
 *  `text` needs them (kitSubsetsFor). Null for a face Fontsource lacks. */
async function fontsourceResolver(family, weight, style, { text = '' } = {}) {
  const id = fontsourceId(family);
  const meta = await fontsourceMeta(family);
  if (meta && !(await fontsourceWeights(family, style)).includes(weight)) 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],
  }));
}

/** Each file's unicode-range (a function: the kit runs after the pen's code). */
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: loads `faces` (as FONTS) for the
 *  sample `text`; `optional` skips a face Fontsource lacks. Files are added in
 *  the order asked, the last winning a shared character. Resolves to the count. */
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 && (await fontsourceWeights(family, style)).includes(weight))) 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 face (fonts.check() says yes to any family). */
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, id = fontsourceId(family)) {
  return (fontsourceMeta.c ??= {})[id] ??= fetch(`https://api.fontsource.org/v1/fonts/${id}`)
    .then((res) => (res.ok ? res.json() : null), () => null);
}

/** The weights the package ships in `style`: the API pairs none (no Libre
 *  Caslon 700 italic file), so italics are read from latin-italic.css. */
function fontsourceWeights(family, style, id = fontsourceId(family)) {
  return (fontsourceWeights.c ??= {})[id + style] ??= fontsourceMeta(family).then(async (m) => {
    if (!m?.styles.includes(style)) return m ? [] : [400, 700];
    const css = style === 'italic' ? await fetch(`${await fontsourceAt(id)}latin-italic.css`).then((r) => (r.ok ? r.text() : ''), () => '') : '';
    const w = [...css.matchAll(/weight: (\d+)/g)].map((x) => +x[1]);
    return w.length ? w : m.weights;
  });
}

// ─── 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 in that style, 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 s = style === 'italic' && meta && !meta.styles.includes('italic') ? 'normal' : style;
  const shipped = meta ? await fontsourceWeights(family, s) : [];
  const weights = shipped.length ? shipped : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  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 ───────────────────────────────────────────────────────────────────────
```

## Variantes

### Imprime las soluciones al final del capítulo

Sin líneas `:::solutions`, `chapterEnd` reúne las soluciones de cada unidad antes del siguiente título de nivel 1.

```diff
-  solutions: { placement: edition === 'teacher' ? 'none' : 'directive' } });
+  solutions: { placement: edition === 'teacher' ? 'none' : 'chapterEnd' } });
```

### Pon el pinyin sobre los caracteres

[La cartilla de pinyin](https://postext.dev/es/cookbook/pinyin-primer.md) pone el pinyin sobre sus caracteres como ruby, algo que un hueco todavía no admite.

## Errores frecuentes

- **Las fuentes chinas se cargan por fragmentos, con el bloque cjk.** Fontsource sirve una familia china, japonesa o coreana en un centenar de archivos por peso, cada uno con un intervalo de caracteres. loadFonts solo descarga el archivo latin, así que en pantalla los caracteres chinos salen de una fuente del sistema y se miden mal, y fontsourceProvider entrega al PDF ese archivo latin, que los imprime como cajas vacías. Añade el bloque cjk del kit, llama a loadCjkFonts(FONTS, markdown) después de loadFonts (una vez por voz, con el texto que compone, si el libro usa varias fuentes chinas) y pasa a renderToPdf fontProvider: cjkPdfProvider: ambos toman los archivos que contienen los caracteres del texto.

- Una lectura todavía no puede ir sobre un hueco: un ruby dentro de `[[…]]` forma parte de la respuesta oculta, y una zona de 田字格 ocupa toda la medida. El apartado 看拼音写词语 pone cada sílaba en su propia línea y la caja debajo, cuatro por fila en un grupo `:::columns`.
- La letra Kai solo compone las respuestas, así que carga únicamente los caracteres de los huecos y de las respuestas modelo; si compone algún carácter más, hay que añadirlo a ese texto.

## Créditos

- Receta: Ignacio Ferro ([@drnachio](https://github.com/drnachio))
- Imágenes: Un pueblo chino a comienzos de la primavera: sauces, golondrinas, flor de melocotonero y dos niños en un camino entre arrozales.: Generated With Diffusion Models, original
- Imágenes: Dos niños cuentan naranjas, manzanas y peras en el puesto de fruta de una abuela, con un gato en un taburete.: Generated With Diffusion Models, original
- Tipografías: Noto Serif SC (OFL-1.1), Noto Sans SC (OFL-1.1), LXGW WenKai TC (OFL-1.1)
- Código: MIT · Contenido de ejemplo: CC-BY-4.0

## Relacionadas

- [N.º 161 · Cuaderno de caligrafía en diez escrituras](https://postext.dev/es/cookbook/handwriting-workbook.md): Un primer cuaderno de caligrafía en cada idioma del sitio: la letra escolar de cada país sobre su pauta, un modelo, letras punteadas y renglones vacíos. · Nivel 2 (Intermedio) · Cuadernos y ejercicios, Libros de texto
- [N.º 076 · Una cartilla con pinyin: la lectura sobre cada carácter](https://postext.dev/es/cookbook/pinyin-primer.md): Ruby carácter a carácter en una cartilla de Hong Kong: {人之初|rén zhī chū} centra una sílaba de pinyin sobre cada carácter, en Andika, en 28 pt de interlineado. · Nivel 2 (Intermedio) · Libros de texto, Cuadernos y ejercicios
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