# 一张练习单，十种学校传统

> 同样七个 :::exercise 块，用十种语言各排一版。每一版用同一个练习样式来排，题号、选项、判断题、填空和除法竖式都照该国课本的习惯。

- HTML版本: https://postext.dev/zh/cookbook/school-traditions-worksheet
- 食谱 No. 169 · 教科书 · 难度 2 (中级) · 输出: Canvas, PDF
- 体裁: 练习册与习题, 教科书
- 需要 postext ≥ 1.59.0, postext-pdf ≥ 1.59.0 · 已用 1.59.0, postext-pdf 1.59.0 测试，日期 2026-10-24
- 页面: [1](https://postext.dev/cookbook/school-traditions-worksheet/zh/p01.webp?v=8e853bba), [2](https://postext.dev/cookbook/school-traditions-worksheet/zh/p02.webp?v=8e853bba)
- PDF: https://postext.dev/cookbook/school-traditions-worksheet/zh/school-traditions-worksheet.pdf?v=8e853bba
- 在沙盒中打开: https://postext.dev/zh/sandbox#recipe=school-traditions-worksheet&lang=zh (.postext: https://postext.dev/cookbook/school-traditions-worksheet/zh/school-traditions-worksheet.postext)
- 最后更新: 2026-10-24
- 其他语言: [en](https://postext.dev/en/cookbook/school-traditions-worksheet.md), [es](https://postext.dev/es/cookbook/school-traditions-worksheet.md), [ca](https://postext.dev/ca/cookbook/school-traditions-worksheet.md), [de](https://postext.dev/de/cookbook/school-traditions-worksheet.md), [fr](https://postext.dev/fr/cookbook/school-traditions-worksheet.md), [it](https://postext.dev/it/cookbook/school-traditions-worksheet.md), [pt](https://postext.dev/pt/cookbook/school-traditions-worksheet.md), [ja](https://postext.dev/ja/cookbook/school-traditions-worksheet.md), [ar](https://postext.dev/ar/cookbook/school-traditions-worksheet.md)

## 简单来说

一张两页的科学和数学练习单，讲水的循环，做了十次。题目都一样；题号、方框、书写线和除法竖式，都照各国课本的样子印。

## 成品一览

四年级科学与数学课程的第 7 张练习单《水的旅行》，排成十个版本。各语言的题目都一样：选一个答案，判断对错，用词语库里的词填空，把词语和意思连起来，圈出一个词，把水箱里的水平均分，说说为什么要节约用水。每个版本都照本国学校的样子印。西班牙文版和加泰罗尼亚文版把题号放在圆圈里，判断题标 V 或 F，除法把除数放在被除数右边的 L 形里。法文版用方块题号、*cases à cocher* 方框和点线空格，作答处是 Seyès 格纸。德文版写 *R* 和 *F*，填空题叫 *Lückentext*，`864 : 4 =` 写成一行，乘号用点。巴西版要在括号里写 V 或 F。英文版在 ⟌ 下面做除法。中文版的大题用一、二、编号，每个题干后面有（　），A. B. C. 排成一行，判断题打 √ 或 ×，最后一题是田字格里的“看拼音，写词语”。日文版用ア イ ウ和○ ×，阿拉伯文版从右往左排，用 أ ب ج 和 صح 或 خطأ。

**这份食谱回答的问题:**

- 怎样把同一张练习单，排成各国课本里练习题的样子？
- 怎样按各国学校的写法排长除法竖式？
- 怎样排中文选择题：题干后的（　）括号和一行排开的 A. B. C. D. 选项？

## 简短回答

```js
// script.js, 行 36–69
// The Markdown of every edition has the same seven exercises. What changes is this table:
// how the number prints, how options are labelled and answered, how true/false reads, where
// a blank is written, the paper of the open answer and the layout of long division.
const disc = { shape: 'disc' };
const square = { shape: 'square' };
const bare = { shape: 'none', suffix: '.' };
const TRADITIONS = {
  es: { number: disc, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  fr: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'seyes', spacing: mm(8) },
    arithmetic: { division: 'potence' } },
  de: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'inline' } },
  it: { number: { shape: 'rounded' }, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  pt: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'bracket' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  en: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
  // 一、二、 sections; （　） after the stem and A. B. C. in a row; √ × in a bracket; 田字格.
  zh: { number: { shape: 'none', format: 'simp-chinese-informal', suffix: '、' },
    options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' },
    area: { kind: 'tianzige', spacing: mm(13), lines: 1 }, arithmetic: { division: 'bracket' } },
  // ア イ ウ in a row with （　）, ○ × in a bracket, the number in a square.
  ja: { number: square, options: { labels: 'katakana', suffix: '', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' }, area: { kind: 'lines' },
    arithmetic: { division: 'bracket' } },
  ar: { number: disc, options: { marker: 'none', prefix: '(', suffix: ')' },
    trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
};
TRADITIONS.ca = TRADITIONS.es; // Catalan schools set exercises as Spanish ones do
```

## 用料

**讲解**

- [练习样式](https://postext.dev/zh/docs/exercises.md#练习样式): exerciseStyles：一类练习的印刷形式，包括题号（圆、方框、标签）、题干、选项字母、空格、判断框、连线圆点、词库、书写区、格子、活动图标与难度标记。
- [竖式计算](https://postext.dev/zh/docs/exercises.md#竖式计算): 竖式计算（+ − ×），每位数字一个格；长除法按各语言学校的写法：英式 ⟌、西欧的直角式，或德式 864 : 4 = 横写。
- [选择题与判断题](https://postext.dev/zh/docs/exercises.md#选择题与判断题): 由任务列表（- [x] 正确，- [ ] 错误）生成选择题，选项标 a) b) c)、A. B. C.、ア イ ウ 或 أ ب ج，配方框、圆圈或括号作答；判断题用该语言的标记：V F、R F、√ ×、○ ×。

**还用到**

- [练习](https://postext.dev/zh/docs/exercises.md#练习)
- [填空与词库](https://postext.dev/zh/docs/exercises.md#填空题与词库)
- [连线与分类](https://postext.dev/zh/docs/exercises.md#连线题与分类题)
- [开放题与书写区](https://postext.dev/zh/docs/exercises.md#问答题与书写区)
- [设计过的章首页](https://postext.dev/zh/docs/configuration-headings.md#通栏与高级设计)
- [标题属性](https://postext.dev/zh/docs/document-format.md#标题属性)
- [语义调色板](https://postext.dev/zh/docs/configuration-fonts-colors-viewers.md#调色板)
- [中日韩字体](https://postext.dev/zh/docs/configuration-pdf-output.md#中文日文和韩文字体)
- [阿拉伯文字体](https://postext.dev/zh/docs/arabic-layout.md#字体)
- [右翻书](https://postext.dev/zh/docs/configuration-page-layout.md#装订)
- [从右向左的文字](https://postext.dev/zh/docs/arabic-layout.md#文字方向与双向算法)
- [断词与文档语言](https://postext.dev/zh/docs/justification.md#支持的语言)
- [在Canvas上绘制页面](https://postext.dev/zh/docs/configuration-programmatic-usage.md#把页面渲染为位图)
- [导出PDF](https://postext.dev/zh/docs/configuration-pdf-output.md#生成pdf)
- [中文断行](https://postext.dev/zh/docs/configuration-east-asian.md#东亚排版)
- [答案](https://postext.dev/zh/docs/exercises.md#答案与解答)
- [段落样式](https://postext.dev/zh/docs/configuration-styles.md#段落样式)
- [嵌入PDF的字体](https://postext.dev/zh/docs/configuration-pdf-output.md#为什么需要字体提供函数)

**配置一览**

- [`bodyText`](https://postext.dev/zh/docs/configuration-text.md#正文), [`colorPalette`](https://postext.dev/zh/docs/configuration-fonts-colors-viewers.md#调色板), `exerciseStyles`, [`footer`](https://postext.dev/zh/docs/configuration-headers-footers.md#页眉与页脚), [`header`](https://postext.dev/zh/docs/configuration-headers-footers.md#页眉与页脚), [`headings`](https://postext.dev/zh/docs/configuration-headings.md#标题), [`layout`](https://postext.dev/zh/docs/configuration-page-layout.md#版式), [`locale`](https://postext.dev/zh/docs/configuration-language.md#断词), [`orderedLists`](https://postext.dev/zh/docs/configuration-lists-math.md#有序列表), [`page`](https://postext.dev/zh/docs/configuration-page-layout.md#页面), [`paragraphStyles`](https://postext.dev/zh/docs/configuration-styles.md#段落样式)

**API**

- [`buildDocument`](https://postext.dev/zh/docs/configuration-programmatic-usage.md#构建文档), [`decompressWoff2`](https://postext.dev/zh/docs/configuration-pdf-output.md#浏览器字体提供函数fontsource--woff2), [`renderPageToCanvas`](https://postext.dev/zh/docs/configuration-programmatic-usage.md#把页面渲染为位图), [`renderToPdf`](https://postext.dev/zh/docs/configuration-pdf-output.md#生成pdf), [`withLoadedFonts`](https://postext.dev/zh/docs/configuration-programmatic-usage.md#排版前加载字体)

**字体**

- Nunito (OFL-1.1), Baloo 2 (OFL-1.1), Noto Serif SC (OFL-1.1), Noto Sans SC (OFL-1.1), Klee One (OFL-1.1), Noto Sans JP (OFL-1.1), Noto Naskh Arabic (OFL-1.1), Baloo Bhaijaan 2 (OFL-1.1)

## 做法

### 1 · 把每种传统写进一张表

```js
// script.js, 行 36–69
// The Markdown of every edition has the same seven exercises. What changes is this table:
// how the number prints, how options are labelled and answered, how true/false reads, where
// a blank is written, the paper of the open answer and the layout of long division.
const disc = { shape: 'disc' };
const square = { shape: 'square' };
const bare = { shape: 'none', suffix: '.' };
const TRADITIONS = {
  es: { number: disc, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  fr: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'seyes', spacing: mm(8) },
    arithmetic: { division: 'potence' } },
  de: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'inline' } },
  it: { number: { shape: 'rounded' }, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  pt: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'bracket' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  en: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
  // 一、二、 sections; （　） after the stem and A. B. C. in a row; √ × in a bracket; 田字格.
  zh: { number: { shape: 'none', format: 'simp-chinese-informal', suffix: '、' },
    options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' },
    area: { kind: 'tianzige', spacing: mm(13), lines: 1 }, arithmetic: { division: 'bracket' } },
  // ア イ ウ in a row with （　）, ○ × in a bracket, the number in a square.
  ja: { number: square, options: { labels: 'katakana', suffix: '', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' }, area: { kind: 'lines' },
    arithmetic: { division: 'bracket' } },
  ar: { number: disc, options: { marker: 'none', prefix: '(', suffix: ')' },
    trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
};
TRADITIONS.ca = TRADITIONS.es; // Catalan schools set exercises as Spanish ones do
```

所有版本的 Markdown 都一样：七个 `:::exercise` 块，答案就写在文字里（`- [x]`、`[[水蒸气]]`、`- 蒸发 -> 水变成水蒸气`、`- 864 ÷ 4`）。各国课本不同的地方在于形式，所以形式只放在这张表里：题号的形状和数字写法，选项的字母，学生是勾方框还是圈字母，判断题的样子，空格的样子，书写区，还有除法竖式的排法。加泰罗尼亚文版原样沿用西班牙文版那一行。

### 2 · 把传统铺在本社样式上

```js
// script.js, 行 73–87
const T = TRADITIONS[LANG];
const ficha = {
  id: 'ficha', ...T,
  number: { background: col('accent'), color: T.number.shape === 'none' ? col('accent')
    : col('paper'), fontFamily: LABEL, fontWeight: 700, ...T.number },
  // Chinese and Japanese sheets set the instructions in the gothic (黑体, ゴシック).
  instruction: { bold: true, color: col('ink'), ...(LANG === 'zh' || LANG === 'ja'
    ? { fontFamily: LABEL } : {}) },
  blank: { color: col('ink'), weight: pt(0.7), ...T.blank },
  match: { look: 'dots', gap: em(5), color: col('accent') },
  bank: { order: 'alpha' },
  area: { color: col('rule'), spacing: mm(9), weight: pt(0.6), ...T.area },
  grid: { cell: mm(8.5), fontFamily: TEXT, rule: col('rule'), color: col('ink') },
  marginTop: mm(7), marginBottom: mm(1), itemSpacing: em(0.4),
};
```

练习样式只有一个，叫 `ficha`，它带着十张练习单共有的东西（题号的蓝色、灰色的线、练习之间的空白），各版本的那一行再铺在它上面。表里没写的，由语言决定：T F、V F、R F、√ ×、○ × 和 صح خطأ 都是引擎自带的词，a) b) c)、A. B. C.、ア イ ウ 和 أ ب ج 也是，所以哪个版本都不用自己写。

### 3 · 给每种文字配字体

```js
// script.js, 行 27–32
const FACES = {
  zh: { text: 'Noto Serif SC', label: 'Noto Sans SC' },
  ja: { text: 'Klee One', label: 'Noto Sans JP' },
  ar: { text: 'Noto Naskh Arabic', label: 'Baloo Bhaijaan 2' },
}[LANG] ?? { text: 'Nunito', label: 'Baloo 2' };
const [TEXT, LABEL] = [FACES.text, FACES.label];
```

拉丁字母的各版共用 Nunito 和 Baloo 2。中文版正文用宋体，题目要求用黑体；日文版正文用教科书体 Klee One，题目要求用一款黑体（ゴシック）；阿拉伯文版用 Noto Naskh Arabic。Klee One 最粗的字重是 600，所以日文版把粗体设成 600（`boldFontWeight`）：如果用 700，浏览器会自己画出加粗效果，页面捕获就会失败。

### 4 · 在练习单顶部留出写姓名的横线

```js
// script.js, 行 91–110
const at = (to, edge, x = 0, y = 0, size) => ({ anchor: { to, edge },
  offset: { x: mm(x), y: mm(y) }, ...(size && { size }) });
const field = (id, attr, x, width) => [
  { kind: 'text', id, content: `{attr.${attr}}`, fontFamily: LABEL, fontSize: pt(10),
    fontWeight: 700, color: col('muted'), align: 'left', placement: at('container', 'top-left',
      x, 28) },
  { kind: 'rule', id: `${id}-line`, direction: 'horizontal', thickness: pt(0.75),
    color: col('rule'), placement: at('container', 'top-left', x + 16, 33, { width: mm(width) }) },
];
const head = { enabled: true, minHeight: mm(38), slot: { elements: [
  { kind: 'box', id: 'band', style: { backgroundColor: col('accent'), borderRadius: mm(3) },
    placement: at('container', 'top-left', 0, 0, { width: 'fill', height: mm(21) }) },
  { kind: 'text', id: 'kicker', content: '{title} · {subtitle}', fontFamily: LABEL,
    fontSize: pt(8.5), fontWeight: 700, color: col('tint'), align: 'left',
    placement: at('container', 'top-left', 6, 3.5) },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: LABEL, fontSize: pt(22),
    fontWeight: 700, color: col('paper'), align: 'left', lineHeight: 1.1,
    placement: at('container', 'top-left', 6, 9.5) },
  ...field('name', 'nombre', 0, 96), ...field('date', 'fecha', 120, 40),
] } };
```

一级标题画出色带、取自 frontmatter 的课程名和标题，还有两个带横线的栏目，栏目里的字取自标题的属性（`nombre="姓名" fecha="日期"`）。所以德文版写着 *Datum*，日文版写着“名前”，代码里却没有一个字符串。

## 完整食谱

一个文件，由食谱文件夹合成，示例文本和排版食谱的公共工具包都已内联；它自己排出页面。要运行它，把它放进空白页面的`<script type="module">`，或粘贴到新建CodePen的JS面板里（设为模块）。它从esm.sh导入postext，不需要安装或构建。

- 食谱文件夹: https://github.com/drnachio/postext/tree/main/cookbook/school-traditions-worksheet

### script.js

```js
// ═══ Postext Cookbook · Nº 169 · One worksheet in ten school traditions ═════════
// https://postext.dev/en/cookbook/school-traditions-worksheet
// Code: MIT · Text: original (CC BY 4.0) · Pictures: none
// Fonts: Nunito, Baloo 2, Klee One, Noto Naskh Arabic and others (SIL OFL) · Needs postext ≥ 1.59.0
import {
  buildDocument, withLoadedFonts, renderPageToCanvas,
} from 'https://esm.sh/postext';
import { renderToPdf, decompressWoff2 } from 'https://esm.sh/postext-pdf';

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

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: a blue-black ink, one blue accent, a pale tint, grey rules
const palette = {
  ink: '#1d2633', accent: '#2a5d9f', tint: '#e8f0fa', rule: '#a9b6c6', muted: '#5d6878',
  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 faces: Latin editions share two faces; Chinese, Japanese and Arabic their own
const FACES = {
  zh: { text: 'Noto Serif SC', label: 'Noto Sans SC' },
  ja: { text: 'Klee One', label: 'Noto Sans JP' },
  ar: { text: 'Noto Naskh Arabic', label: 'Baloo Bhaijaan 2' },
}[LANG] ?? { text: 'Nunito', label: 'Baloo 2' };
const [TEXT, LABEL] = [FACES.text, FACES.label];
// #endregion

// #region answer: the form of the exercises, as each country's school books set them
// The Markdown of every edition has the same seven exercises. What changes is this table:
// how the number prints, how options are labelled and answered, how true/false reads, where
// a blank is written, the paper of the open answer and the layout of long division.
const disc = { shape: 'disc' };
const square = { shape: 'square' };
const bare = { shape: 'none', suffix: '.' };
const TRADITIONS = {
  es: { number: disc, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  fr: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'seyes', spacing: mm(8) },
    arithmetic: { division: 'potence' } },
  de: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'inline' } },
  it: { number: { shape: 'rounded' }, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  pt: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'bracket' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  en: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
  // 一、二、 sections; （　） after the stem and A. B. C. in a row; √ × in a bracket; 田字格.
  zh: { number: { shape: 'none', format: 'simp-chinese-informal', suffix: '、' },
    options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' },
    area: { kind: 'tianzige', spacing: mm(13), lines: 1 }, arithmetic: { division: 'bracket' } },
  // ア イ ウ in a row with （　）, ○ × in a bracket, the number in a square.
  ja: { number: square, options: { labels: 'katakana', suffix: '', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' }, area: { kind: 'lines' },
    arithmetic: { division: 'bracket' } },
  ar: { number: disc, options: { marker: 'none', prefix: '(', suffix: ')' },
    trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
};
TRADITIONS.ca = TRADITIONS.es; // Catalan schools set exercises as Spanish ones do
// #endregion

// #region style: the one exercise style, the edition's tradition over the house look
const T = TRADITIONS[LANG];
const ficha = {
  id: 'ficha', ...T,
  number: { background: col('accent'), color: T.number.shape === 'none' ? col('accent')
    : col('paper'), fontFamily: LABEL, fontWeight: 700, ...T.number },
  // Chinese and Japanese sheets set the instructions in the gothic (黑体, ゴシック).
  instruction: { bold: true, color: col('ink'), ...(LANG === 'zh' || LANG === 'ja'
    ? { fontFamily: LABEL } : {}) },
  blank: { color: col('ink'), weight: pt(0.7), ...T.blank },
  match: { look: 'dots', gap: em(5), color: col('accent') },
  bank: { order: 'alpha' },
  area: { color: col('rule'), spacing: mm(9), weight: pt(0.6), ...T.area },
  grid: { cell: mm(8.5), fontFamily: TEXT, rule: col('rule'), color: col('ink') },
  marginTop: mm(7), marginBottom: mm(1), itemSpacing: em(0.4),
};
// #endregion

// #region head: the worksheet's head, its title on a tinted band and the lines for a name
const at = (to, edge, x = 0, y = 0, size) => ({ anchor: { to, edge },
  offset: { x: mm(x), y: mm(y) }, ...(size && { size }) });
const field = (id, attr, x, width) => [
  { kind: 'text', id, content: `{attr.${attr}}`, fontFamily: LABEL, fontSize: pt(10),
    fontWeight: 700, color: col('muted'), align: 'left', placement: at('container', 'top-left',
      x, 28) },
  { kind: 'rule', id: `${id}-line`, direction: 'horizontal', thickness: pt(0.75),
    color: col('rule'), placement: at('container', 'top-left', x + 16, 33, { width: mm(width) }) },
];
const head = { enabled: true, minHeight: mm(38), slot: { elements: [
  { kind: 'box', id: 'band', style: { backgroundColor: col('accent'), borderRadius: mm(3) },
    placement: at('container', 'top-left', 0, 0, { width: 'fill', height: mm(21) }) },
  { kind: 'text', id: 'kicker', content: '{title} · {subtitle}', fontFamily: LABEL,
    fontSize: pt(8.5), fontWeight: 700, color: col('tint'), align: 'left',
    placement: at('container', 'top-left', 6, 3.5) },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: LABEL, fontSize: pt(22),
    fontWeight: 700, color: col('paper'), align: 'left', lineHeight: 1.1,
    placement: at('container', 'top-left', 6, 9.5) },
  ...field('name', 'nombre', 0, 96), ...field('date', 'fecha', 120, 40),
] } };
// #endregion

const config = {
  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' }),
  colorPalette,
  page: { sizePreset: 'custom', width: mm(210), height: mm(297), dpi: 150,
    margins: { top: mm(18), bottom: mm(20), left: mm(18), right: mm(18), mirror: true } },
  layout: { layoutType: 'single' },
  bodyText: {
    fontFamily: TEXT, fontSize: pt(LANG === 'ar' ? 13.5 : 12), lineHeight: pt(LANG === 'ar'
      ? 22 : 18), color: col('ink'), boldColor: col('ink'), italicColor: col('ink'),
    referenceColor: col('ink'), textAlign: 'left', firstLineIndent: pt(0),
    boldFontWeight: LANG === 'ja' ? 600 : 700, // Klee One's heaviest cut is 600
    paragraphSpacing: false, hyphenation: { enabled: false }, optimalLineBreaking: true,
    avoidWidows: true, avoidOrphans: true, avoidRunts: true,
  },
  headings: { fontFamily: LABEL, color: col('ink'), fontWeight: 700, levels: [
    { level: 1, fontSize: pt(20), breakBefore: { parity: 'any' }, marginTop: pt(0),
      marginBottom: mm(1), advancedDesign: head },
  ] },
  exerciseStyles: [ficha],
  orderedLists: { fontFamily: LABEL, color: col('accent'), fontWeight: 700, marginTop: pt(0),
    marginBottom: pt(0) },
  paragraphStyles: [{ id: 'colophon', fontFamily: TEXT, fontSize: pt(7.5), lineHeight: pt(10),
    color: col('muted'), firstLineIndent: pt(0), marginTop: mm(6) }],
  header: { elements: [] },
  footer: { elements: [{ kind: 'text', id: 'folio', content: '{pageNumber}', fontFamily: LABEL,
    fontSize: pt(9), fontWeight: 700, color: col('accent'), align: 'center',
    placement: at('page', 'bottom', 0, -11) }] },
};

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
title: "科学与数学 · 四年级"
subtitle: "练习单 7"
---

# 水的旅行 {nombre="姓名" fecha="日期"}

地球上的水一直在流动。太阳晒热大海，水升到天空，又变成雨或雪落回地面。这段旅行叫作水循环。

:::exercise
选择题。（把正确答案的字母填在括号里）

1. 从云里落下来的水叫作
   - [ ] 水蒸气
   - [x] 雨
   - [ ] 雾
2. 太阳晒热大海时，海水会
   - [x] 蒸发
   - [ ] 结冰
   - [ ] 下沉
:::

:::exercise{type="truefalse"}
判断题。（对的打“√”，错的打“×”）

- [x] 云是由许多小水滴组成的。
- [ ] 天气变冷时，冰会融化。
- [x] 河流把水送回大海。
- [ ] 雨水是咸的，因为它来自大海。
:::

:::exercise{bank}
选词填空。

::bank[冰 | 风]

太阳晒热[[大海]]，海水变成[[水蒸气]]升上天空。水蒸气遇冷，聚成[[云]]。最后，水又变成[[雨]]或雪落下来。
:::

:::exercise
连一连。

- 蒸发 -> 水变成水蒸气
- 凝结 -> 水蒸气变成小水滴
- 降水 -> 水从云里落下
- 下渗 -> 水渗进土里
:::

:::exercise
圈出正确的词语。

1. 雪是[[液态 | (固态)]]的水。
2. [[(晴天) | 阴天]]的时候，水坑干得更快。
3. 地球上的水大部分是[[淡水 | (咸水)]]。
:::

:::exercise{type="arithmetic"}
学校的水箱能装 864 升水，平均分给 4 个班，每个班分到多少升？列竖式计算，并验算。

- 864 ÷ 4
- 216 × 4
:::

:::exercise{type="open" lines="1"}
看拼音，写词语。

zhēng fā　　　yún duǒ　　　jiàng yǔ　　　hé liú

:::solution
蒸发　云朵　降雨　河流
:::
:::

:::paragraphs{style="colophon"}
正文用 Noto Serif SC，标题用 Noto Sans SC（SIL OFL）· 原创文本（CC BY 4.0）
:::
`; // content.<lang>.md, inlined by the Cookbook

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = {
  Nunito: ['400', '700'], 'Baloo 2': ['700'], // the Latin editions
  'Noto Serif SC': ['400', '700'], 'Noto Sans SC': ['700'], // 宋 for the text, 黑 for heads
  'Klee One': ['400', '600'], 'Noto Sans JP': ['600', '700'], // 教科書体 and a gothic
  'Noto Naskh Arabic': ['400', '700'], 'Baloo Bhaijaan 2': ['700'],
};

// ─── 4 · Build & show ───────────────────────────────────────────────────────
// The edition loads its own faces only.
for (const family of Object.keys(FONTS)) if (![TEXT, LABEL].includes(family)) delete FONTS[family];
await loadFonts(FONTS, markdown);
await loadCjkFonts(FONTS, markdown);
await loadArabicFonts(FONTS, markdown);
const doc = await withLoadedFonts(() => buildDocument({ markdown }, config),
  { ...kitFonts(FONTS), text: markdown });
showBook(doc, { title: t({ en: 'Worksheet', es: 'Ficha', ca: 'Fitxa', fr: 'Fiche',
  de: 'Arbeitsblatt', it: 'Scheda', pt: 'Ficha', zh: '练习单', ja: 'プリント', ar: 'ورقة عمل' }) });
offerPdf(() => renderToPdf(doc, { fontProvider: { zh: cjkPdfProvider, ja: cjkPdfProvider,
  ar: arabicPdfProvider }[LANG] ?? fontsourceProvider }), `${RECIPE}-${LANG}.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 · 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 ───────────────────────────────────────────────────────────────────────
```

## 变化

### 印教师版

每个答案都用品红色印在自己的位置上：括号、方框、空格和商。

```diff
   exerciseStyles: [ficha],
+  exercises: { edition: 'teacher' },
```

### 把答案集中到练习单底部

`placement: 'after'` 把每道题的答案排在题目下面；`'inverted'` 把答案倒过来印，就像谜题页那样。

```diff
+  exercises: { solutions: { placement: 'inverted', layout: 'key' } },
```

## 常见问题

- 字体如果没有 700 的字重，题干编号的粗体就是合成出来的。给这种正文字体设一个 `boldFontWeight`，用它实际带有的字重。
- 日文题目要求里的○和中文题目要求里的√只有 CJK 字体里才有：把它们放在 CJK 正文的句子里，不要放进拉丁字母的标签。

## 致谢

- 食谱: Ignacio Ferro ([@drnachio](https://github.com/drnachio))
- 字体: Nunito (OFL-1.1), Baloo 2 (OFL-1.1), Noto Serif SC (OFL-1.1), Noto Sans SC (OFL-1.1), Klee One (OFL-1.1), Noto Sans JP (OFL-1.1), Noto Naskh Arabic (OFL-1.1), Baloo Bhaijaan 2 (OFL-1.1)
- 代码: MIT · 示例内容: CC-BY-4.0

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