# An Arabic workbook, right to left

> A primary Arabic workbook unit set right to left: choices with أ ب ج, matching columns, a word bank, صح or خطأ boxes, a word search and Arabic-Indic digits.

- HTML version: https://postext.dev/en/cookbook/arabic-workbook-rtl
- Recipe Nº 173 · Textbooks · Level 2 (Intermediate) · Outputs: Canvas, PDF
- Genres: Workbooks & exercises, Textbooks
- Requires postext ≥ 1.59.0, postext-pdf ≥ 1.59.0 · tested with 1.59.0, postext-pdf 1.59.0 on 2026-10-24
- Pages: [١](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p01.webp?v=cd08e1dc), [٢](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p02.webp?v=cd08e1dc), [٣](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p03.webp?v=cd08e1dc), [٤](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p04.webp?v=cd08e1dc), [1](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p05.webp?v=cd08e1dc), [2](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p06.webp?v=cd08e1dc), [3](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p07.webp?v=cd08e1dc), [4](https://postext.dev/cookbook/arabic-workbook-rtl/ar/p08.webp?v=cd08e1dc)
- Open in Sandbox: https://postext.dev/en/sandbox#recipe=arabic-workbook-rtl&lang=ar (.postext: https://postext.dev/cookbook/arabic-workbook-rtl/ar/arabic-workbook-rtl.postext)
- Last updated: 2026-10-24
- Other languages: [es](https://postext.dev/es/cookbook/arabic-workbook-rtl.md), [ca](https://postext.dev/ca/cookbook/arabic-workbook-rtl.md), [de](https://postext.dev/de/cookbook/arabic-workbook-rtl.md), [fr](https://postext.dev/fr/cookbook/arabic-workbook-rtl.md), [it](https://postext.dev/it/cookbook/arabic-workbook-rtl.md), [pt](https://postext.dev/pt/cookbook/arabic-workbook-rtl.md), [zh](https://postext.dev/zh/cookbook/arabic-workbook-rtl.md), [ja](https://postext.dev/ja/cookbook/arabic-workbook-rtl.md), [ar](https://postext.dev/ar/cookbook/arabic-workbook-rtl.md)

## In short

Pages of a children's Arabic workbook about a school garden: pick the answer, join the columns, fill gaps from a box of words, mark right or wrong, order words, find words in a grid.

## What you'll build

A unit of a second-year Arabic workbook on a 17 × 24 cm page, about a school garden. A watercolour band opens it, with the unit's tab and title and a dotted line each for name, class and date. Then come the exercises an Arab primary book prints: choose the right answer, with أ) ب) ج) three to a row; join the two columns; fill the gaps from a word bank; mark صح or خطأ; put the words in order and write the sentence on the line; find seven garden words in a grid of letters. The solutions close the unit. The same text is set twice: the Mashriq edition numbers everything in Arabic-Indic digits, ١ ٢ ٣, and the Maghreb edition in European ones. Both read from the right and bind on the right.

**This recipe answers:**

- How do I set an Arabic workbook right to left, with matching columns, a word search and Arabic-Indic digits?
- How do I set a workbook page of activities: numbers in discs, a word bank, true or false, join with a line?
- How do I make a word search or a crossword from a list of words?

## The short answer

One exercise style read right to left, in the edition's digits.

```js
// script.js, lines 34–53
// The locale sets the direction, the binding and the digits: 'ar' writes the exercise
// numbers, the items and the key in Arabic-Indic digits (١ ٢ ٣), 'ar-MA' in European ones.
// Options take the abjad letters (أ ب ج), true/false the words صح / خطأ, both from the
// language. Nothing below names a side: the engine sets every part from the right.
const tamrin = {
  id: 'tamrin',
  number: { shape: 'disc', fontFamily: LABEL, background: col('accent') },
  instruction: { fontFamily: LABEL, bold: false, color: col('ink') },
  options: { layout: 'row' }, // أ) ب) ج) side by side, three to a row (columns=3)
  blank: { look: 'dots', color: col('muted') }, // a dotted line, as Arab workbooks print it
  match: { color: col('accent') },
  bank: { box: 'sunduq', order: 'shuffle' },
  area: { kind: 'lines', color: col('rule') },
  grid: { fontFamily: TEXT, rule: col('leaf'), uppercase: false }, // Arabic has no capitals
  answers: { color: col('leaf'), fontFamily: TEXT },
  solutions: { box: 'hulul' },
  marginTop: em(1.1), marginBottom: em(0.5),
};
// The solutions where :::solutions stands: at the end of the unit.
const exercises = { solutions: { placement: 'directive' } };
```

## Ingredients

**Teaches**

- [Exercises](https://postext.dev/en/docs/exercises.md#exercises): The :::exercise fence: an activity whose instruction, items and answers are in the Markdown, numbered and laid out as an exercise style says, the same in print and on screen.
- [Right-to-left text](https://postext.dev/en/docs/arabic-layout.md#direction-and-the-bidirectional-algorithm): direction sets the base direction of the document: 'auto' (the default) takes it from the script of locale, so 'ar', 'fa' or 'he' run right to left; the bidirectional algorithm (UAX #9) orders the Latin words and numbers inside each line, and the book binds on the right.
- [Digits of the generated numbers](https://postext.dev/en/docs/configuration-language.md#document-language): numerals ('auto', 'latn', 'arab', 'arabext') picks the digits of every number the engine writes: folios, list and note numbers, heading and figure counters, the pages of the contents and the index. 'auto' follows locale: ١٢٣ for Arabic, 1 2 3 in the Maghreb (ar-MA, ar-DZ, ar-TN). The author's own text is never rewritten.

**Also uses**

- [Exercise styles](https://postext.dev/en/docs/exercises.md#exercise-styles)
- [Choice and true or false](https://postext.dev/en/docs/exercises.md#choice-and-true-or-false)
- [Gaps and word banks](https://postext.dev/en/docs/exercises.md#gaps-and-word-banks)
- [Matching and sorting](https://postext.dev/en/docs/exercises.md#matching-and-sorting)
- [Ordering](https://postext.dev/en/docs/exercises.md#ordering)
- [Word searches and crosswords](https://postext.dev/en/docs/exercises.md#word-searches-and-crosswords)
- [Solutions](https://postext.dev/en/docs/exercises.md#solutions)
- [Arabic fonts](https://postext.dev/en/docs/arabic-layout.md#fonts)
- [Arabic numbering styles](https://postext.dev/en/docs/arabic-layout.md#digits-and-numeral-styles)
- [Books bound on the right](https://postext.dev/en/docs/configuration-page-layout.md#binding)
- [Inline chips](https://postext.dev/en/docs/configuration-styles.md#chip-styles)
- [Callout boxes](https://postext.dev/en/docs/configuration-callouts.md#callout-styles)
- [Designed openers](https://postext.dev/en/docs/configuration-headings.md#span-and-advanced-design)
- [Heading attributes](https://postext.dev/en/docs/document-format.md#heading-attributes)
- [Pictures in page designs](https://postext.dev/en/docs/configuration-headers-footers.md#image-elements)
- [Semantic colour palette](https://postext.dev/en/docs/configuration-fonts-colors-viewers.md#color-palette)
- [PDF export](https://postext.dev/en/docs/configuration-pdf-output.md#generating-pdfs)
- [Boxes that split or stay whole](https://postext.dev/en/docs/configuration-callouts.md#the-callout-container)
- [Column balancing](https://postext.dev/en/docs/configuration-page-flow.md#column-balancing)
- [Open questions and writing areas](https://postext.dev/en/docs/exercises.md#open-questions-and-writing-areas)
- [Heads by page role](https://postext.dev/en/docs/configuration-headers-footers.md#text-elements)
- [Paragraph styles](https://postext.dev/en/docs/configuration-styles.md#paragraph-styles)
- [Fonts embedded in the PDF](https://postext.dev/en/docs/configuration-pdf-output.md#why-a-font-provider)
- [Figures and tables as resources](https://postext.dev/en/docs/document-format-resources.md#resources)

**Config at a glance**

- [`bodyText`](https://postext.dev/en/docs/configuration-text.md#body-text), [`calloutStyles`](https://postext.dev/en/docs/configuration-callouts.md#callout-styles), [`chipStyles`](https://postext.dev/en/docs/configuration-styles.md#chip-styles), [`colorPalette`](https://postext.dev/en/docs/configuration-fonts-colors-viewers.md#color-palette), `exerciseStyles`, `exercises`, [`footer`](https://postext.dev/en/docs/configuration-headers-footers.md#headers--footers), [`header`](https://postext.dev/en/docs/configuration-headers-footers.md#headers--footers), [`headings`](https://postext.dev/en/docs/configuration-headings.md#headings), [`layout`](https://postext.dev/en/docs/configuration-page-layout.md#layout), [`locale`](https://postext.dev/en/docs/configuration-language.md#hyphenation), [`orderedLists`](https://postext.dev/en/docs/configuration-lists-math.md#ordered-lists), [`page`](https://postext.dev/en/docs/configuration-page-layout.md#page), [`paragraphStyles`](https://postext.dev/en/docs/configuration-styles.md#paragraph-styles)

**APIs**

- [`buildDocument`](https://postext.dev/en/docs/configuration-programmatic-usage.md#building-a-document), [`decompressWoff2`](https://postext.dev/en/docs/configuration-pdf-output.md#browser-font-provider-fontsource--woff2), [`registerResourceImage`](https://postext.dev/en/docs/architecture.md#api-surface), [`renderPageToCanvas`](https://postext.dev/en/docs/configuration-programmatic-usage.md#rendering-a-page-to-a-bitmap), [`renderToPdf`](https://postext.dev/en/docs/configuration-pdf-output.md#generating-pdfs), [`withLoadedFonts`](https://postext.dev/en/docs/configuration-programmatic-usage.md#loading-fonts-before-layout)

**Typefaces**

- Noto Naskh Arabic (OFL-1.1), Baloo Bhaijaan 2 (OFL-1.1)

## Method

### 1 · Name no side

The code is [the short answer](https://postext.dev/en/cookbook/arabic-workbook-rtl.md#the-short-answer) above. `locale: 'ar'` sets the text right to left, binds the book on the right and picks the digits; the exercise style takes the abjad letters for the options and صح and خطأ for true or false from the language. The matching columns, the word bank, the word search and the writing lines are drawn as box designs, which a right-to-left page mirrors: the first column stands on the right, a word read across the grid runs from right to left, and the dots of the match face each other in the middle.

### 2 · The garden opener

```js
// script.js, lines 58–73
const BAND = 170 / 2.4; // mm: the painting's height at the page's width
const opener = { enabled: true, minHeight: mm(BAND - 20 + 21), slot: { elements: [
  { kind: 'image', id: 'picture', resourceId: '{attr.pic}', decorative: true, reserve: false,
    placement: { anchor: { to: 'page', edge: 'top-left' },
      size: { width: mm(170), height: mm(BAND) } } },
  // In the flow of a right-to-left page 'left' is the start of the line: the right.
  { kind: 'text', id: 'unit', content: '{attr.kicker}', fontFamily: LABEL, fontSize: pt(11),
    fontWeight: 700, color: col('paper'), align: 'left',
    box: { backgroundColor: col('accent'), borderRadius: mm(1.5),
      padding: { top: mm(0.6), bottom: mm(0.4), left: mm(2.4), right: mm(2.4) } },
    placement: { anchor: { to: 'container', edge: 'top-left' },
      offset: { x: mm(0), y: mm(BAND - 20 + 3) } } },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: LABEL, fontSize: pt(30),
    fontWeight: 700, color: col('ink'), align: 'left',
    placement: { anchor: { to: '#unit', edge: 'right-of' }, offset: { x: mm(4), y: mm(-5) } } },
] } };
```

The painting is anchored to the page and keeps its place; the tab and the title are laid in the flow of the page, where `left` is the start of the line, so they stand on the right without a coordinate of their own. The folios stay physical, as running heads do, and name each side.

### 3 · Two editions, two sets of digits

```js
// script.js, lines 227–232
// Both are bound on the right and read from the right; only the locale changes.
const build = () => withLoadedFonts(() => buildDocument({ markdown, resources }, config()),
  { ...kitFonts(FONTS), text: markdown });
const mashriq = await build();
edition = { locale: 'ar-MA' }; // the same book for Morocco: European digits, still right to left
const docs = [mashriq, await build()];
```

The configuration is a function, so each build gets its own object, and the second one only changes the locale. `ar-MA` writes the exercise numbers, the items, the key and the folios in European digits and leaves everything else as it was: the direction, the binding, the abjad letters and the words of the key.

## The whole recipe

One file, composed from the recipe's folder with the sample text and the Cookbook's shared kit inlined; it builds its own page. To run it, put it in a `<script type="module">` on an empty page, or paste it into the JS panel of a new CodePen (as a module). It imports postext from esm.sh, so there is nothing to install or build.

- Source folder: https://github.com/drnachio/postext/tree/main/cookbook/arabic-workbook-rtl

### script.js

```js
// ═══ Postext Cookbook · Nº 173 · An Arabic workbook, right to left ═══════════════
// https://postext.dev/en/cookbook/arabic-workbook-rtl
// Code: MIT · Text: original (CC BY 4.0) · Pictures: generated with diffusion models
// Fonts: Noto Naskh Arabic, Baloo Bhaijaan 2 (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 = 'ar'; // @lang: the language of the frame; the workbook is Arabic in all
const RECIPE = 'arabic-workbook-rtl';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: a garden workbook: ink, a terracotta accent, a leaf green, sand
const palette = {
  ink: '#22282e', // text
  accent: '#b9542a', // the one accent: exercise numbers, the unit tab, the word bank
  leaf: '#4f7d3a', // the second: rules and the word search's ruling
  sand: '#f8eedf', // the bank's ground, the answers box
  rule: '#c8b49b', // writing lines
  muted: '#6f655c', // folios, the name line, the colophon
  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
// Naskh for the text, a rounded Arabic for the labels a child reads first.
const [TEXT, LABEL] = ['Noto Naskh Arabic', 'Baloo Bhaijaan 2'];

// #region answer: one exercise style read right to left, in the edition's digits
// The locale sets the direction, the binding and the digits: 'ar' writes the exercise
// numbers, the items and the key in Arabic-Indic digits (١ ٢ ٣), 'ar-MA' in European ones.
// Options take the abjad letters (أ ب ج), true/false the words صح / خطأ, both from the
// language. Nothing below names a side: the engine sets every part from the right.
const tamrin = {
  id: 'tamrin',
  number: { shape: 'disc', fontFamily: LABEL, background: col('accent') },
  instruction: { fontFamily: LABEL, bold: false, color: col('ink') },
  options: { layout: 'row' }, // أ) ب) ج) side by side, three to a row (columns=3)
  blank: { look: 'dots', color: col('muted') }, // a dotted line, as Arab workbooks print it
  match: { color: col('accent') },
  bank: { box: 'sunduq', order: 'shuffle' },
  area: { kind: 'lines', color: col('rule') },
  grid: { fontFamily: TEXT, rule: col('leaf'), uppercase: false }, // Arabic has no capitals
  answers: { color: col('leaf'), fontFamily: TEXT },
  solutions: { box: 'hulul' },
  marginTop: em(1.1), marginBottom: em(0.5),
};
// The solutions where :::solutions stands: at the end of the unit.
const exercises = { solutions: { placement: 'directive' } };
// #endregion


// #region opener: the garden to the bleed, the unit's tab and its title under it
const BAND = 170 / 2.4; // mm: the painting's height at the page's width
const opener = { enabled: true, minHeight: mm(BAND - 20 + 21), slot: { elements: [
  { kind: 'image', id: 'picture', resourceId: '{attr.pic}', decorative: true, reserve: false,
    placement: { anchor: { to: 'page', edge: 'top-left' },
      size: { width: mm(170), height: mm(BAND) } } },
  // In the flow of a right-to-left page 'left' is the start of the line: the right.
  { kind: 'text', id: 'unit', content: '{attr.kicker}', fontFamily: LABEL, fontSize: pt(11),
    fontWeight: 700, color: col('paper'), align: 'left',
    box: { backgroundColor: col('accent'), borderRadius: mm(1.5),
      padding: { top: mm(0.6), bottom: mm(0.4), left: mm(2.4), right: mm(2.4) } },
    placement: { anchor: { to: 'container', edge: 'top-left' },
      offset: { x: mm(0), y: mm(BAND - 20 + 3) } } },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: LABEL, fontSize: pt(30),
    fontWeight: 700, color: col('ink'), align: 'left',
    placement: { anchor: { to: '#unit', edge: 'right-of' }, offset: { x: mm(4), y: mm(-5) } } },
] } };
// #endregion

// Folios at the foot's outer corner: running heads stay physical, so each side is named.
const foot = (id, content, parity, edge, x, extra = {}) => ({ kind: 'text', id, content, parity,
  pages: 'body', fontFamily: LABEL, fontSize: pt(9), color: col('muted'),
  placement: { anchor: { to: 'page', edge }, offset: { x: mm(x), y: mm(-11) } }, ...extra });
const footer = { elements: [
  foot('folio-v', '{pageNumber}', 'even', 'bottom-left', 16,
    { fontWeight: 700, color: col('accent') }),
  foot('title-v', '{title}', 'even', 'bottom-left', 24),
  foot('folio-r', '{pageNumber}', 'odd', 'bottom-right', -16,
    { fontWeight: 700, color: col('accent'), align: 'right' }),
  foot('title-r', '{chapterTitle}', 'odd', 'bottom-right', -24, { align: 'right' }),
] };

let edition = {}; // what the second build below changes: the Maghreb edition's locale
const config = () => ({
  locale: 'ar', // the Mashriq edition: ١ ٢ ٣
  colorPalette,
  exerciseStyles: [tamrin],
  exercises,
  page: { sizePreset: 'custom', width: mm(170), height: mm(240), dpi: 150,
    margins: { top: mm(20), bottom: mm(20), left: mm(18), right: mm(16), mirror: true } },
  layout: { layoutType: 'single' },
  bodyText: { fontFamily: TEXT, fontSize: pt(13), lineHeight: pt(22), color: col('ink'),
    boldColor: col('ink'), italicColor: col('ink'), referenceColor: col('ink'),
    textAlign: 'justify', firstLineIndent: pt(0), hyphenation: { enabled: false },
    avoidWidows: true, avoidOrphans: true },
  headings: { fontFamily: LABEL, color: col('ink'), fontWeight: 700,
    balancing: { enabled: false },
    levels: [{ level: 1, fontSize: pt(30), breakBefore: { parity: 'any' },
      advancedDesign: opener }] },
  orderedLists: { numberFormat: 'arabic', color: col('ink'), fontWeight: 700 },
  paragraphStyles: [
    { id: 'ism', fontFamily: LABEL, fontSize: pt(11), color: col('muted'), firstLineIndent: pt(0),
      textAlign: 'left', marginBottom: mm(3) },
    { id: 'colophon', fontFamily: LABEL, fontSize: pt(8), lineHeight: pt(13), color: col('muted'),
      textAlign: 'left', firstLineIndent: pt(0), marginTop: mm(6) },
  ],
  chipStyles: [{ id: 'khatt', backgroundEnabled: false, underline: 'dotted', borderWidth: pt(1),
    borderColor: col('muted'), minWidth: mm(26), paddingX: pt(0), paddingY: pt(0) }],
  calloutStyles: [
    { id: 'sunduq', background: col('sand'), border: { enabled: true, color: col('accent'),
      width: pt(1), style: 'dashed' }, borderRadius: mm(2.5),
    padding: { top: mm(2), right: mm(4), bottom: mm(2.5), left: mm(4) },
    body: { fontFamily: LABEL, fontSize: pt(12), textAlign: 'center' },
    marginTop: mm(1.5), marginBottom: mm(2.5) },
    { id: 'hulul', background: col('sand'), borderRadius: mm(2),
      stripe: { enabled: true, side: 'left', width: pt(3), color: col('leaf') },
      padding: { top: mm(3), right: mm(4), bottom: mm(3.5), left: mm(4) },
      titleStyle: { fontFamily: LABEL, fontSize: pt(13), fontWeight: 700, color: col('leaf') },
      body: { fontSize: pt(11), lineHeight: pt(19), color: col('ink'), firstLineIndent: pt(0) },
      marginTop: mm(6), marginBottom: mm(2), keepTogether: false },
  ],
  header: { elements: [] },
  footer,
  ...edition,
});

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
title: "كراسة التمارين · الصف الثاني"
---

# في الحديقة {kicker="الوحدة الثالثة" pic="garden"}

:::paragraphs{style="ism"}
الاسم: :chip[ ]{style="khatt"}  الصف: :chip[ ]{style="khatt"}  التاريخ: :chip[ ]{style="khatt"}
:::

:::exercise{columns=3}
اخترِ الإجابة الصحيحة.

1. تحتاج النبتة كي تنمو إلى:
   - [ ] الحجارة
   - [x] الماء
   - [ ] الرمل
2. نسقي الحديقة في الصباح الباكر لأنّ الشمس فيه:
   - [x] ليست حارّة
   - [ ] شديدة الحرارة
   - [ ] غائبة
3. يصنع النحل العسل من:
   - [ ] أوراق الشجر
   - [ ] حبّات التراب
   - [x] رحيق الأزهار
:::

:::exercise
صِلْ كلّ كلمة في العمود الأول بما يناسبها في العمود الثاني.

- النحلة -> تصنع العسل
- الشمس -> تمنح الضوء والدفء
- الجذور -> تمتصّ الماء من التربة
- الفراشة -> تنتقل من زهرة إلى زهرة
:::

:::exercise{bank}
أكمِلِ الفراغ بالكلمة المناسبة من الصندوق.

زرعت سلمى بذرة [[الليمون]] في أصيص صغير، ووضعته قرب [[النافذة]] حتى يصله الضوء، وصارت [[تسقيه]] كلّ يومين. وبعد أسبوعين ظهرت ورقتان [[خضراوان]].

::bank[الملح | السيّارة]
:::

:::exercise{type=truefalse}
ضع علامة في المربّع المناسب.

- [x] تصنع النحلة العسل من رحيق الأزهار.
- [ ] تنمو شجرة الليمون في يوم واحد.
- [x] الجذور تثبّت النبتة في التربة.
- [ ] نسقي النباتات بالحليب.
:::

:::exercise{type=scramble}
رتّبِ الكلمات لتكوّن جملة مفيدة، ثمّ اكتبها على السطر.

- تسقي / سلمى / الأزهار / في / الصباح
- يحمل / خالد / أصيص / النعناع
:::

:::exercise{type=wordsearch size=8}
ابحث في الشبكة عن أسماء الأشياء التي نراها في الحديقة، ثمّ لوّنها.

- شجرة
- زهرة
- تربة
- بذرة
- ورقة
- نحلة
- غصن
:::

:::solutions

:::paragraphs{style="colophon"}
الحروف: Noto Naskh Arabic وBaloo Bhaijaan 2 (رخصة SIL OFL) · الرسم: مولَّد بنماذج الانتشار · التمارين: نصّ أصليّ للكتاب (CC BY 4.0)
:::
`; // content.ar.md: one text for both editions

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = {
  'Noto Naskh Arabic': ['400', '700'], // the text, the word search's letters
  'Baloo Bhaijaan 2': ['400', '700'], // instructions, numbers, the title
};

// ─── 4 · Build & show ───────────────────────────────────────────────────────
await loadFonts(FONTS, markdown);
// Each Arabic face's letters live in a file of their own (gotcha: arabic-fonts-subset).
await loadArabicFonts(FONTS, markdown);
await loadImage('garden-1600.jpg', asset('garden-1600.jpg'));
const resources = [{ id: 'garden', typeId: 'figure', kind: 'bitmap', createdAt: 0, updatedAt: 0,
  bitmap: { fileId: 'garden-1600.jpg', format: 'jpeg', width: 1600, height: 667 } }];
// #region editions: one text, two editions: Mashriq digits, then Maghreb digits
// Both are bound on the right and read from the right; only the locale changes.
const build = () => withLoadedFonts(() => buildDocument({ markdown, resources }, config()),
  { ...kitFonts(FONTS), text: markdown });
const mashriq = await build();
edition = { locale: 'ar-MA' }; // the same book for Morocco: European digits, still right to left
const docs = [mashriq, await build()];
// #endregion
showBook(docs, { title: t({ ar: 'كراسة تمارين عربية', en: 'An Arabic workbook, right to left',
  es: 'Un cuaderno de ejercicios árabe, de derecha a izquierda' }) });
offerPdf(() => renderToPdf(docs, { fontProvider: arabicPdfProvider, 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 · 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 · book v1 ── books bound on either edge · postext.dev/cookbook
// A book bound on the right (Arabic, Hebrew or Persian text, vertical
// Chinese, or page.binding 'right') opens from what a Latin reader calls
// the back: page 1 lies alone on the left of the spine, then [3 | 2].

/** showPages for a book bound on either edge. A right-bound book (the
 *  document says so: doc.binding is 'right' for page.binding 'right', for
 *  text that runs right to left and for vertical text, when the binding is
 *  left to 'auto') 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-book')) {
    // The pages keep direction ltr, as in a left-bound book: a canvas takes
    // the direction its element inherits, and under the spread's rtl a run
    // painted for an ltr canvas would end where the engine starts it.
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit-book">
      .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 ───────────────────────────────────────────────────────────────────────
```

## Variations

### Print the teacher's book

The answers then print in their places, in the colour of `answers`: the dots joined, the words in their blanks, the right boxes filled and the words ringed in the grid.

```diff
-const exercises = { solutions: { placement: 'directive' } };
+const exercises = { edition: 'teacher', solutions: { placement: 'none' } };
```

### Write the exercises in Chinese

[The Chinese exercise book](https://postext.dev/en/cookbook/chinese-exercise-book.md) sets the same kinds of exercise with its own brackets and numerals.

## Pitfalls

- **Tag an Arabic book 'ar', not with LANG.** A recipe's editions are en and es, but an Arabic sample is Arabic in both: `locale: LANG` would set it left to right, bind it on the left, number its pages 1 2 3 and caption its figures Figure or Figura. From postext 1.30 the tag is also the language the text is shaped in (measured, painted and embedded), so under an English or Spanish tag a face such as Markazi Text does not draw the Arabic forms of its guillemets and stops, and the lines break elsewhere. Write the tag yourself: 'ar' (Arabic-Indic digits, the Mashriq convention), a region such as 'ar-EG' or 'ar-SA', or 'ar-MA', 'ar-DZ' or 'ar-TN' for a Maghreb edition with European digits. A Latin page that only quotes Arabic keeps its own locale.
- **Arabic faces need their arabic file, through the arabic block.** Fontsource serves Amiri, Noto Naskh Arabic or Scheherazade New as one file per subset, and the Arabic letters are in the arabic file. loadFonts fetches only latin (and latin-ext), so on screen the Arabic comes from a system face and measures wrong, and fontsourceProvider hands the PDF that latin file, which prints empty boxes. List the arabic kit block, call loadArabicFonts(FONTS, markdown) after loadFonts, with every weight the pages set in Arabic listed in FONTS, and give renderToPdf fontProvider: arabicPdfProvider.

- Most Arabic faces have no ✓ or ✗: the true or false words are صح and خطأ, and the instruction asks for a mark in the box.
- The word search fills its empty cells with the letters of its own words, in their isolated forms. Choose words whose letters vary, or the grid fills with ة.

## Credits

- Recipe: Ignacio Ferro ([@drnachio](https://github.com/drnachio))
- Images: A school garden in an Arab town: date palms, a fountain, lemon trees, a girl watering plants and a boy carrying a pot of mint.: Generated With Diffusion Models, original
- Type: Noto Naskh Arabic (OFL-1.1), Baloo Bhaijaan 2 (OFL-1.1)
- Code: MIT · Sample content: CC-BY-4.0

## Related

- [Nº 161 · Handwriting workbook in ten scripts](https://postext.dev/en/cookbook/handwriting-workbook.md): A first handwriting book in every site language: each country's school script on its own ruling, a model, dotted letters to trace and empty rows. · Level 2 (Intermediate) · Workbooks & exercises, Textbooks
- [Nº 109 · A Maghreb edition of an Arabic text, with European digits](https://postext.dev/en/cookbook/maghreb-edition-european-digits.md): An Arabic chapter printed for Morocco: locale 'ar-MA' keeps the text right to left and bound on the right, and writes every generated number as 1, 2, 3. · Level 1 (Basic) · Manuals, guides & reference
- [Nº 171 · A Chinese exercise book, pupil's and teacher's](https://postext.dev/en/cookbook/chinese-exercise-book.md): A 练习册 in Chinese and maths: sections 一、二、, （　） brackets, 田字格 and sums in columns, built twice from one text, for the pupil and the teacher. · Level 2 (Intermediate) · Workbooks & exercises, Textbooks