Cartilla de lectura amb síl·labes en xips

// ═══ Postext Cookbook · Nº 060 · Early reader with syllable chips ════════════════
// https://postext.dev/en/cookbook/reading-primer-syllables
// Code: MIT · Text: original (CC BY 4.0) · Pictures: diffusion models · Icons: drawn in code
// Fonts: Andika, DynaPuff, Playpen Sans (SIL OFL 1.1) · Needs postext ≥ 1.4.1
import {
  buildDocument, renderPageToCanvas, clearMeasurementCache, registerResourceImage, setCellImage,
} from 'https://esm.sh/postext';

const LANG = 'es'; // @lang: the language of the sample document ('en' | 'es')
const RECIPE = 'reading-primer-syllables';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
const palette = { ink: '#242832', paper: '#ffffff', muted: '#5f6470', // text; instructions
  cream: '#f6f0e3', rule: '#d3c9b6', // the band, the tiles and the pictures' ground; guides
  // The vowel code: a syllable takes its vowel's colour. White on these fills measures
  // 3.2–4.9:1, above WCAG's 3:1 for large text: the vowel chips are bold, 20 pt or more.
  a: '#d9482b', e: '#dd740c', i: '#1f9a8f', o: '#3f6fd8', u: '#9152cf' };
// Design elements read the hex and ignore the palette (gotcha: palette-skips-designs).
const col = (id) => ({ hex: palette[id], model: 'hex', paletteId: id });
// The engine's defaults are linked to 'main-color': point it at the ink.
const colorPalette = Object.entries({ ...palette, 'main-color': palette.ink })
  .map(([id, hex]) => ({ id, name: id, value: { hex, model: 'hex' } }));
const [TEXT, DISPLAY, LABEL] = ['Andika', 'DynaPuff', 'Playpen Sans']; // Andika: one-storey a
const [TOP, SIDE, GRID] = [18, 20, 15]; // mm, mm, pt: every activity starts on the 15 pt grid

// #region answer: one chip style per vowel, and {ma·má} in the text written out as chips
// A word's syllables are chips with nothing between them, so their boxes touch and the white
// border draws the seam. Across a word space a chip keeps at least `gap`: 0.5 em sets the
// words of a 24 pt row 4.2 mm apart, where the space alone leaves 2.3 mm. Inside a sentence
// the '-frase' twins keep no gap, so the word space alone parts a chip from the word before.
// A 24 pt chip, padding and border included, is 10.4 mm tall (gotcha: chip-overlap).
const syllable = { fontFamily: TEXT, bold: true, borderWidth: pt(1), borderColor: col('paper'),
  paddingX: em(0.26), paddingY: em(0.05), gap: em(0.5) };
const chipStyles = [
  ...'aeiou'.split('').flatMap((v) => [ // one pair per vowel
    { ...syllable, id: v, background: col(v), color: col('paper') }, // a syllable with m
    { ...syllable, id: `${v}-borde`, background: col('paper'), color: col(v), borderColor: col(v) },
  ]).flatMap((style) => [style, { ...style, id: `${style.id}-frase`, gap: em(0) }]),
  { ...syllable, id: 'pinta', bold: false, background: col('paper'), color: col('ink'),
    borderColor: col('ink'), borderWidth: pt(0.8) }, // an outline for the child to colour in
];
const vowel = (s) => s.normalize('NFD').toLowerCase().match(/[aeiou]/)[0]; // 'mú' → 'u'
const chipOf = (s, end) => `:chip[${s}]{style="${vowel(s)}${/m/i.test(s) ? '' : '-borde'}${end}"}`;
// {mi·mo·sa} → :chip[mi]{style="i"}:chip[mo]{style="o"}:chip[sa]{style="a-borde"}, and a word
// written after another word, as in 'me {mi·ma}.', takes the '-frase' twins.
const syllables = (text) => text.replace(/(\p{L} )?\{([\p{L}·]+)\}/gu, (_, before = '', word) =>
  before + word.split('·').map((s) => chipOf(s, before ? '-frase' : '')).join(''));
// #endregion

const at = (x, y, size, edge = 'top-left') => ({ anchor: { to: 'page', edge },
  offset: { x: mm(x), y: mm(y) }, ...(size && { size }) });
const words = (id, content, family, size, weight, color, placement, extra) => ({ kind: 'text',
  id, content, fontFamily: family, fontSize: pt(size), fontWeight: weight, color: col(color),
  align: 'left', overflow: 'wrap', placement, ...extra });
const picture = (id, resourceId, placement) => ({ kind: 'image', id, resourceId, placement });
const tag = { textTransform: 'uppercase', letterSpacing: pt(1.5) };

// #region opener: the letter's page: a cream band, a giant Mm and two things that start with m
const BAND = 104; // mm: the depth of the band's drawing; its wave dips to 101.9 mm
// Images reserve no height in an opener (gotcha: opener-image-no-reserve): by itself the
// opener ends at the foot of the word manzana, 88.7 mm down, and the first title starts on
// the wave's edge. 16 grid lines of minHeight start it on the grid, 11.4 mm below the wave.
const opener = { enabled: true, minHeight: pt(16 * GRID),
  slot: { elements: [
    picture('band', 'banda', at(0, 0, { width: mm(210), height: mm(BAND) })),
    words('unit', '{attr.unit}', LABEL, 9, 700, 'paper', at(SIDE, 12.5), { ...tag,
      box: { backgroundColor: col('ink'), borderRadius: mm(3),
        padding: { top: mm(1.2), right: mm(2.8), bottom: mm(1.2), left: mm(2.8) } } }),
    words('kicker', '{attr.kicker}', LABEL, 8.5, 600, 'muted', // level with the pill's text
      { anchor: { to: '#unit', edge: 'right-of' }, offset: { x: mm(4), y: mm(1.4) } }, tag),
    words('letter', '{titleText}', DISPLAY, 190, 700, 'ink', at(SIDE - 3, 19), { lineHeight: 1 }),
    words('name', '{attr.name}', LABEL, 20, 600, 'ink', at(SIDE + 1, 76)),
    picture('butterfly', 'mariposa', at(146, 12, { width: mm(40) })),
    picture('apple', 'manzana', at(151, 53, { width: mm(30) })),
    ...[['mariposa', 45.5], ['manzana', 84.5]].map(([name, y]) => words(name, name, LABEL, 10,
      600, 'muted', at(146, y, { width: mm(40) }), { align: 'center' })), // under each picture
  ] } };
// #endregion

// #region activities: each activity heading draws its icon beside the title
const ICON = 9; // mm
const H2 = { level: 2, marginBottom: pt(0), // two grid lines per title, and two above it
  lineHeight: pt(2 * GRID), marginTop: pt(2 * GRID) };
const activity = (id, icon) => ({ id, advancedDesign: { enabled: true, slot: { elements: [
  picture('icon', icon, { anchor: { to: 'container', edge: 'top-left' },
    size: { width: mm(ICON), height: mm(ICON) } }),
  words('title', '{titleText}', LABEL, 15, 700, 'ink', { anchor: { to: '#icon',
    edge: 'right-of' }, offset: { x: mm(3) }, size: { width: mm(140), height: mm(ICON) } },
  { verticalAlign: 'middle' }), // centred on the icon
] } } });
// #endregion

// #region pictures: six picture words in a rounded grid, each picture inside its cell
const PICTURE_WORDS = ['ma·no', 'ma·pa', 'me·sa', 'mi·mo·sa', 'mo·no', 'mu·ñe·ca'];
const tableStyles = [{ id: 'dibujos', borderRadius: mm(5), // the frame and its fills, rounded
  headerBackgroundEnabled: false, // a header row added later would print grey (#f0f0f0)
  bodyBackgroundEnabled: true, bodyBackground: col('cream'), // cream tiles…
  rules: 'grid', borderColor: col('paper'), borderWidth: pt(4), // …parted by white rules
  bodyFontSize: pt(20), cellPadding: mm(3) }]; // the words' chips are 20 pt
const cells = (row) => PICTURE_WORDS.slice(row * 3, row * 3 + 3)
  .map((word) => ({ content: syllables(`{${word}}`), align: 'center' }));
let grid = { columnWidths: [1, 1, 1], rows: [cells(0), cells(1)] };
PICTURE_WORDS.forEach((word, k) => { // the picture above the word, 0.72 of the cell's width
  const resourceId = word.replaceAll('·', '').replace('ñ', 'n');
  grid = setCellImage(grid, { row: Math.floor(k / 3), col: k % 3 }, { resourceId, width: 0.72 });
});
// #endregion

// The type of every picture and the table: its empty captionPrefix prints no caption line.
const sheet = { id: 'lamina', name: 'Lámina', shortLabel: '', captionPrefix: '',
  numberingTemplate: '{n}', resetOn: 'never', counterFormat: 'decimal' };
const here = (id, rest) => ({ id, typeId: 'lamina', createdAt: 0, updatedAt: 0,
  placement: { position: 'here' }, ...rest });

const FOLIO = 9; // mm: the folio's disc
const folio = (parity, edge, x, textEdge, textX) => [
  words(`n-${parity}`, '{pageNumber}', DISPLAY, 12, 700, 'paper',
    at(x, -10, { width: mm(FOLIO), height: mm(FOLIO) }, edge),
    { align: 'center', verticalAlign: 'middle', parity,
      box: { backgroundColor: col('ink'), borderRadius: mm(FOLIO / 2) } }),
  words(`s-${parity}`, '{title} · {attr.unit}: {attr.name}', LABEL, 8, 600, 'muted',
    at(textX, -10, { width: mm(100), height: mm(FOLIO) }, textEdge),
    { parity, verticalAlign: 'middle', align: textEdge.endsWith('left') ? 'left' : 'right' }),
];

const config = () => ({ // a factory, never a shared object (gotcha: config-cache-identity)
  colorPalette, chipStyles, tableStyles, resourceTypes: [sheet],
  page: { width: mm(210), height: mm(260), dpi: 150, margins: { top: mm(TOP), bottom: mm(20),
    left: mm(SIDE), right: mm(SIDE) } }, // equal sides: nothing to mirror
  layout: { layoutType: 'single' },
  bodyText: { fontFamily: TEXT, fontSize: pt(11), lineHeight: pt(GRID), color: col('ink'),
    referenceColor: col('ink'), // the palette never reaches it (gotcha: palette-skips-designs)
    textAlign: 'left', firstLineIndent: pt(0) }, // ragged: 1.4.1 hyphenates no ragged text
  headings: { fontFamily: LABEL, // the titles print through designs, but are measured in it
    balancing: { enabled: false }, // or page 37's spare grid line goes above its first title
    levels: [
      // Restated: any headings object drops the H1 break (gotcha: headings-drop-h1-break).
      // A unit opens on a recto. span 'page' paints the band into the top margin, where a
      // design kept in the column is cut off at the column's top edge.
      { level: 1, span: 'page', breakBefore: { enabled: true, parity: 'odd' },
        advancedDesign: opener }, H2] },
  headingStyles: [activity('oye', 'oreja'), activity('lee', 'libro'), activity('mira', 'ojo'),
    activity('repasa', 'lapiz')],
  // #region reading: the child's lines on multiples of the 15 pt grid, the instructions at 10 pt
  // A 24 pt chip is 10.4 mm tall: at 30 pt (10.6 mm) leading the chips of two sentences would
  // stand 0.1 mm apart, so every line the child reads has 45 pt, and the syllables 60 pt.
  paragraphStyles: [
    { id: 'consigna', fontFamily: LABEL, fontSize: pt(10), lineHeight: pt(GRID),
      color: col('muted') }, // the instruction under each activity
    { id: 'fila', fontSize: pt(34), lineHeight: pt(4 * GRID), textAlign: 'center' },
    { id: 'palabras', fontSize: pt(24), lineHeight: pt(3 * GRID), textAlign: 'center' },
    { id: 'lectura', fontSize: pt(24), lineHeight: pt(3 * GRID) },
    { id: 'colofon', fontSize: pt(7.5), lineHeight: pt(10), // Andika: Playpen has no italic
      color: col('muted'), marginTop: pt(GRID) },
  ],
  // #endregion
  // #region boxes: an activity on cream, the note for the family under a rule
  calloutStyles: [
    { id: 'colorea', background: col('cream'), borderRadius: mm(4),
      marginTop: pt(0), // the :::space before the box is the whole gap above it
      padding: { top: mm(4), right: mm(5), bottom: mm(5), left: mm(5) },
      titleStyle: { fontFamily: LABEL, fontSize: pt(15), fontWeight: 700, color: col('ink') },
      body: { fontFamily: LABEL, fontSize: pt(10), lineHeight: pt(GRID), color: col('muted') } },
    { id: 'familia', backgroundEnabled: false,
      stripe: { enabled: true, side: 'top', width: pt(2.5), color: col('rule') },
      padding: { top: mm(3), right: mm(0), bottom: mm(0), left: mm(0) },
      titleStyle: { fontFamily: LABEL, fontSize: pt(8.5), fontWeight: 700, color: col('ink'),
        ...tag },
      body: { fontSize: pt(10.5), lineHeight: pt(GRID) } },
  ],
  // #endregion
  header: { elements: [] },
  footer: { elements: [ // the folio on the outer edge, the series beside it
    ...folio('odd', 'bottom-right', -SIDE, 'bottom-right', -(SIDE + FOLIO + 3)),
    ...folio('even', 'bottom-left', SIDE, 'bottom-left', SIDE + FOLIO + 3)] },
});

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
Mostra en Markdown · 90 línies · content.es.md
title: "Letra a letra"
---

# Mm {kicker="Letra a letra · Cartilla de lectura 1" unit="Unidad 7" name="la eme"}

## Escucha y repite {style="oye"}

:::paragraphs{style="consigna"}
Lee las sílabas en voz alta, en orden y después salteadas. Abajo, la eme va al final.
:::

:::paragraphs{style="fila"}
{ma} {me} {mi} {mo} {mu}

{am} {em} {im} {om} {um}
:::

## Lee las palabras {style="lee"}

:::paragraphs{style="consigna"}
Cada sílaba lleva el color de su vocal. Las que tienen eme van rellenas.
:::

:::paragraphs{style="palabras"}
{ma·má} {a·mo} {Me·mo} {e·me}

{mí·o} {mi·mo} {ma·mi} {mí·a}
:::

## Mira y lee {style="mira"}

:::paragraphs{style="consigna"}
Di el nombre de cada dibujo y léelo por sílabas.
:::

::resource{id="dibujos"}

## Repasa {style="repasa"}

:::paragraphs{style="consigna"}
Empieza en el punto y sigue la flecha. Luego repasa las sílabas.
:::

::resource{id="trazos"}

## Lee las frases {style="lee"}

:::paragraphs{style="consigna"}
Lee despacio. La primera vez que sale una palabra nueva, va partida en sílabas.
:::

:::paragraphs{style="lectura"}
Mi mamá me {mi·ma}.

Mamá me {a·ma}.

Yo amo a mi mamá.

Memo mima a {Mi·mí}.
:::

:::space{lines=1}

:::callout{type="colorea" title="Lee y colorea"}
Estos son los colores de las vocales:

:::paragraphs{style="palabras"}
:chip[a]{style="a"} :chip[e]{style="e"} :chip[i]{style="i"} :chip[o]{style="o"} :chip[u]{style="u"}
:::

:::space{lines=1}

Colorea cada sílaba con el color de su vocal.

:::paragraphs{style="palabras"}
:chip[mo]{style="pinta"} :chip[ma]{style="pinta"} :chip[mu]{style="pinta"} :chip[me]{style="pinta"} :chip[mi]{style="pinta"} :chip[ma]{style="pinta"}

:chip[mi]{style="pinta"} :chip[me]{style="pinta"} :chip[mo]{style="pinta"} :chip[mu]{style="pinta"} :chip[ma]{style="pinta"} :chip[mo]{style="pinta"}
:::
:::

:::callout{type="familia" title="Para la familia"}
Lean juntos las sílabas de la página 37: primero en orden y después salteadas. Si su hijo o su hija duda entre *ma* y *me*, no le dé la respuesta: señale la vocal y pregúntele de qué color es. Diez minutos al día bastan; es mejor parar cuando todavía tiene ganas de seguir.
:::

:::paragraphs{style="colofon"}
*Letra a letra* es una cartilla inventada para el Recetario de Postext. Texto: CC BY 4.0. Acuarelas: modelos de difusión.

Compuesta en Andika, DynaPuff y Playpen Sans (SIL Open Font License).
:::
`; // content.<lang>.md, inlined by the Cookbook

// #region art: the band, the icons and the tracing rows, drawn in the palette's colours
// The picture words are watercolours, JPEGs in assets/ painted on white and multiplied by the
// cream, so they sit on the band and the tiles without a box. The rest is drawn here, with no
// words in it: an SVG drawn as an image cannot use web fonts (gotcha: svg-no-webfonts), so the
// tracing letters are strokes and every label is set by the page.
const P = palette;
const n = (v) => +v.toFixed(2);
const svgDoc = (w, h, body) => `<svg xmlns="http://www.w3.org/2000/svg" width="${w * 10}" `
  + `height="${h * 10}" viewBox="0 0 ${w} ${h}">${body}</svg>`;
const shape = (d, fill) => `<path d="${d}" fill="${fill}"/>`;
const line = (d, color, w, extra = '') => `<path d="${d}" fill="none" stroke="${color}" `
  + `stroke-width="${w}" stroke-linecap="round" stroke-linejoin="round"${extra}/>`;
const dot = (x, y, r, fill) => `<circle cx="${n(x)}" cy="${n(y)}" r="${n(r)}" fill="${fill}"/>`;
const drawings = {
  banda: () => svgDoc(210, BAND, shape(`M0 0H210V${BAND - 6}C190 ${BAND - 1} 172 ${BAND - 9} 150 `
    + `${BAND - 6}S102 ${BAND + 1} 76 ${BAND - 5} 28 ${BAND - 12} 0 ${BAND - 6}Z`, P.cream)),
};
// The activity icons: a white glyph on an ink disc.
const icon = (glyph) => svgDoc(20, 20, dot(10, 10, 10, P.ink) + glyph);
Object.assign(drawings, {
  oreja: () => icon(line('M7.5 8.5C7.5 5 10 3.5 12.5 3.5C15.5 3.5 16.5 6 16.5 8C16.5 11 13.5 '
    + '11.5 13 14C12.5 16.5 10 17 8.5 15.5M10 8.5C10 7 11 6 12.5 6C13.8 6 14.3 7.2 14 8.3',
  P.paper, 1.5)),
  ojo: () => icon(line('M3.5 10Q10 3.5 16.5 10Q10 16.5 3.5 10Z', P.paper, 1.5)
    + dot(10, 10, 2.4, P.paper)),
  libro: () => icon(line('M10 6.5C7.5 5 5.5 5 4 5.8V14.8C5.5 14 7.5 14 10 15.5C12.5 14 14.5 14 '
    + '16 14.8V5.8C14.5 5 12.5 5 10 6.5ZM10 6.5V15.5', P.paper, 1.3)),
  lapiz: () => icon(line('M5.5 14.5L6.5 11L13.5 4L16 6.5L9 13.5ZM12 5.5L14.5 8', P.paper, 1.3)),
});
// Tracing: rows on writing guides, a model letter in ink, then dashed ones to go over.
const TRACE = { w: 170, first: 26, pitch: 20.5 }; // mm
const guides = (b) => line(`M0 ${b - 16}H${TRACE.w}M0 ${b}H${TRACE.w}`, P.rule, 0.4)
  + line(`M0 ${b - 8}H${TRACE.w}`, P.rule, 0.35, ' stroke-dasharray="1 1"');
// Letters as strokes: x-height 8, capitals 16, from the baseline b; [path, width].
const glyphs = {
  m: (x, b) => [`M${x} ${b - 8}V${b}M${x} ${b - 5.4}C${x} ${b - 7.4} ${x + 1.4} ${b - 8} `
    + `${x + 2.7} ${b - 8}S${x + 5.3} ${b - 7.2} ${x + 5.3} ${b - 5.4}V${b}M${x + 5.3} ${b - 5.4}`
    + `C${x + 5.3} ${b - 7.4} ${x + 6.7} ${b - 8} ${x + 8} ${b - 8}S${x + 10.6} ${b - 7.2} `
    + `${x + 10.6} ${b - 5.4}V${b}`, 10.6],
  M: (x, b) => [`M${x} ${b}V${b - 16}L${x + 6} ${b - 6}L${x + 12} ${b - 16}V${b}`, 12],
  a: (x, b) => [`M${x + 6.4} ${b - 4}A3.2 4 0 0 0 ${x} ${b - 4}A3.2 4 0 0 0 ${x + 6.4} ${b - 4}`
    + `M${x + 6.4} ${b - 8}V${b}`, 6.4],
  e: (x, b) => [`M${x + 0.2} ${b - 4}H${x + 6.8}C${x + 6.8} ${b - 6.4} ${x + 5.2} ${b - 8} `
    + `${x + 3.5} ${b - 8}S${x + 0.2} ${b - 6.2} ${x + 0.2} ${b - 4}S${x + 1.8} ${b} ${x + 3.7} `
    + `${b}C${x + 5} ${b} ${x + 6} ${b - 0.5} ${x + 6.7} ${b - 1.3}`, 6.8],
  i: (x, b) => [`M${x + 0.6} ${b - 8}V${b}M${x + 0.6} ${b - 11.4}V${b - 11}`, 1.2],
  o: (x, b) => [`M${x + 6.8} ${b - 4}A3.4 4 0 0 0 ${x} ${b - 4}A3.4 4 0 0 0 ${x + 6.8} ${b - 4}`,
    6.8],
  u: (x, b) => [`M${x} ${b - 8}V${b - 2.8}C${x} ${b - 1} ${x + 1.3} ${b} ${x + 3} ${b}S${x + 6.2} `
    + `${b - 1} ${x + 6.2} ${b - 2.8}M${x + 6.2} ${b - 8}V${b}`, 6.2],
};
const KERN = 1.8; // mm between letters
const write = (word, x, b) => word.split('').reduce(([d, at], ch) => {
  const [path, w] = glyphs[ch](at, b);
  return [d + path, at + w + KERN];
}, ['', x]); // [path, x after the last letter + KERN]
const dashed = ([d]) => line(d, P.muted, 1, ' stroke-dasharray="1.1 1"');
// The model: ink strokes, a teal dot where the pencil starts and an arrow beside the stem
// pointing the way the first stroke goes (dir 1 down, −1 up).
const model = (letter, b, [x, y], dir) => line(write(letter, 4, b)[0], P.ink, 1.3)
  + dot(x, y, 1.2, P.i) + line(`M${x - 2.4} ${y + dir * 1.5}V${y + dir * 6}`, P.i, 0.6)
  + shape(`M${x - 3.5} ${y + dir * 5.2}H${x - 1.3}L${x - 2.4} ${y + dir * 7.2}Z`, P.i);
const repeat = (letter, b) => Array.from({ length: 7 }, (_, k) =>
  dashed(write(letter, TRACE.first + k * TRACE.pitch, b))).join('');
// The five syllables, each centred in a fifth of the row.
const syllableRow = (b) => ['ma', 'me', 'mi', 'mo', 'mu'].map((syll, k) => {
  const w = write(syll, 0, b)[1] - KERN;
  return dashed(write(syll, (k + 0.5) * (TRACE.w / 5) - w / 2, b));
}).join('');
drawings.trazos = () => svgDoc(TRACE.w, 67, guides(17) + model('m', 17, [4, 9], 1)
  + repeat('m', 17) + guides(41) + model('M', 41, [4, 41], -1) + repeat('M', 41)
  + guides(65) + syllableRow(65));
// The watercolours, by resource id: [file, width, height] in px.
const PAINTINGS = {
  mariposa: ['mariposa-660.jpg', 660, 540], manzana: ['manzana-480.jpg', 480, 480],
  ...Object.fromEntries(['mano', 'mapa', 'mesa', 'mimosa', 'mono', 'muneca']
    .map((id) => [id, [`${id}-640.jpg`, 640, 480]])) };
const ALT = { banda: 'Franja de color crema con el borde ondulado',
  manzana: 'Una manzana roja con una hoja', mariposa: 'Una mariposa morada con manchas amarillas',
  mano: 'Una mano abierta', mapa: 'Un mapa del tesoro con un río y un camino hasta una cruz',
  mesa: 'Una mesa con una manzana y una taza', mono: 'Un mono sentado',
  mimosa: 'Una rama de mimosa con flores amarillas y hojas plumosas',
  muneca: 'Una muñeca de trapo con coletas y vestido morado',
  oreja: 'Una oreja', ojo: 'Un ojo', libro: 'Un libro abierto', lapiz: 'Un lápiz',
  trazos: 'Tres pautas: la eme minúscula y la mayúscula, cada una con un modelo y siete de puntos '
    + 'para repasar, y las sílabas ma, me, mi, mo y mu de puntos' };
// Each picture is a resource that the opener, a heading style, a table cell or the text names
// by id. Drawings in px, 10 to the millimetre (the viewBox's own).
const size = (svg) => svg.match(/width="(\d+)" height="(\d+)"/).slice(1).map(Number);
const common = (id) => ({ id, typeId: 'lamina', altText: ALT[id], createdAt: 0, updatedAt: 0 });
const artwork = [...Object.entries(drawings).map(([id, draw]) => {
  const [width, height] = size(draw());
  return { ...common(id), kind: 'svg', svg: { fileId: `${id}.svg`, width, height },
    ...(id === 'trazos' && here(id)) };
}), ...Object.entries(PAINTINGS).map(([id, [fileId, w, h]]) => ({ ...common(id),
  kind: 'bitmap', bitmap: { fileId, format: 'jpeg', width: w, height: h } }))];
// #endregion

const resources = [...artwork, here('dibujos', { kind: 'table',
  table: { styleId: 'dibujos', model: grid } })];

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = { Andika: ['400', '700'], DynaPuff: ['700'], 'Playpen Sans': ['400', '600', '700'] };

// ─── 4 · Build & show ───────────────────────────────────────────────────────
const text = syllables(markdown);
await Promise.all([loadFonts(FONTS, text), // every face before the build (gotcha: fonts-first)
  ...Object.entries(drawings).map(([id, draw]) => loadSvg(`${id}.svg`, draw())),
  ...Object.values(PAINTINGS).map(([file]) => loadImage(file, asset(file)))]);
const continuation = { pageIndexOffset: 36, pageNumbering: { startAt: 37 } }; // 37: a recto
const doc = await buildWithFonts(() => buildDocument({ markdown: text, resources, continuation },
  config()), text);
showPages(doc, { title: 'Letra a letra · La eme' });

Kit · core, fonts, viewer, images: igual a totes les receptes · 270 línies
// ─── 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 v1 ── the same in every recipe · postext.dev/cookbook ────────
// Postext measures text with the faces the browser has loaded, and caches the
// widths, so every face must be ready before the first build. Faces come from
// Fontsource: the same static files the PDF embeds, so screen and PDF agree.

/** faces = { 'Family Name': ['400', '400i', '700'] }. `text` is the sample:
 *  letters beyond Latin-1 (č, ł, ő…) also load the latin-ext files. With
 *  `optional`, a face Fontsource does not ship is skipped instead of failing.
 *  Resolves to the number of faces added. */
async function loadFonts(faces, text = '', { optional = false } = {}) {
  kitStatus('Loading fonts…');
  const ranges = {
    latin: 'U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,'
      + 'U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD',
    'latin-ext': 'U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,'
      + 'U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF',
  };
  const subsets = /[Ā-˿Ḁ-ỿ]/.test(text) ? ['latin', 'latin-ext'] : ['latin'];
  const jobs = [];
  let added = 0;
  for (const [family, specs] of Object.entries(faces)) {
    const id = fontsourceId(family);
    const meta = optional ? await fontsourceMeta(family) : null;
    for (const spec of new Set(specs)) {
      const weight = parseInt(spec, 10);
      const style = spec.endsWith('i') ? 'italic' : 'normal';
      if (hasFace(family, weight, style)) continue;
      if (optional && !(meta?.weights.includes(weight) && meta.styles.includes(style))) continue;
      for (const subset of subsets) {
        const url = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-${subset}-${weight}-${style}.woff2`;
        const face = new FontFace(family, `url(${url}) format('woff2')`,
          { weight: String(weight), style, unicodeRange: ranges[subset] });
        jobs.push(face.load().then((ready) => { document.fonts.add(ready); added++; }, () => {
          if (subset === 'latin' && !optional) throw new Error(`Fontsource has no ${family} ${weight} ${style}`);
        }));
      }
    }
  }
  await Promise.all(jobs).catch((error) => { kitFail(error); throw error; });
  return added;
}

/** Runs `build` (a buildDocument or buildBundle call) and checks the faces
 *  the pages use. A regular face missing from FONTS is loaded with a warning;
 *  bold and italic variants are loaded when the family ships them. Then the
 *  measurement caches are cleared and the build runs again. */
async function buildWithFonts(build, text = '') {
  const tried = new Set();
  for (let round = 0; round < 3; round++) {
    kitStatus('Laying out…');
    await new Promise(requestAnimationFrame);          // let the status paint first
    const result = await Promise.resolve().then(build).catch((error) => { kitFail(error); throw error; });
    const wanted = { base: {}, variants: {} };
    for (const { font, base } of [result].flat().flatMap(fontStringsOf)) {
      const { family, weight, style } = parseFont(font);
      const key = `${family}|${weight}|${style}`;
      if (tried.has(key) || hasFace(family, weight, style)) continue;
      tried.add(key);
      (wanted[base ? 'base' : 'variants'][family] ??= []).push(`${weight}${style === 'italic' ? 'i' : ''}`);
    }
    if (Object.keys(wanted.base).length) {
      console.warn(`[cookbook] FONTS does not list ${JSON.stringify(wanted.base)}: loading them.`);
    }
    const added = await loadFonts(wanted.base, text) + await loadFonts(wanted.variants, text, { optional: true });
    if (added === 0) return result;
    clearMeasurementCache();
  }
  throw new Error('The fonts did not settle after three builds.');
}

/** Every font string of the layout. `base` marks a block's own face; its
 *  bold, italic and bold-italic variants are listed whether or not used. */
function fontStringsOf(doc) {
  const found = new Map();
  const walk = (node) => {
    if (!node || typeof node !== 'object') return;
    if (Array.isArray(node)) { node.forEach(walk); return; }
    for (const [key, value] of Object.entries(node)) {
      if (typeof value === 'string' && /fontString$/i.test(key)) {
        found.set(value, found.get(value) || key === 'fontString');
      } else if (value && typeof value === 'object') walk(value);
    }
  };
  walk(doc.pages);
  walk(doc.blocks);
  return [...found].map(([font, base]) => ({ font, base }));
}

/** '700 37.5px Open Sans' / 'italic 400 13px "Source Serif 4"' → { family, weight, style }.
 *  A string with no weight ('95.8px Young Serif', from a design text) is 400. */
function parseFont(font) {
  const m = /^(?:(italic|oblique)\s+)?(?:small-caps\s+)?(?:(\d+|bold|normal)\s+)?[\d.]+px\s+(.+)$/.exec(font.trim());
  if (!m) throw new Error(`Unexpected font string: ${font}`);
  const weight = m[2] === 'bold' ? 700 : !m[2] || m[2] === 'normal' ? 400 : Number(m[2]);
  return { family: m[3].replace(/^["']|["']$/g, ''), weight, style: m[1] ? 'italic' : 'normal' };
}

/** True when a loaded FontFace covers exactly this family, weight and style
 *  (document.fonts.check() is also true for families nobody declared). */
function hasFace(family, weight, style) {
  for (const face of document.fonts) {
    if (face.status !== 'loaded' || face.style !== style) continue;
    if (face.family.replace(/^["']|["']$/g, '') !== family) continue;
    const [low, high = low] = face.weight.split(' ').map(Number);
    if (weight >= low && weight <= high) return true;
  }
  return false;
}

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

/** The weights and styles a family ships ({ weights: [400, 700], styles: ['normal', 'italic'] }), or null. */
function fontsourceMeta(family) {
  fontsourceMeta.cache ??= new Map();
  const id = fontsourceId(family);
  if (!fontsourceMeta.cache.has(id)) {
    fontsourceMeta.cache.set(id, fetch(`https://api.fontsource.org/v1/fonts/${id}`)
      .then((res) => (res.ok ? res.json() : null), () => null));
  }
  return fontsourceMeta.cache.get(id);
}

// ─── Kit · viewer v1 ── the same in every recipe · postext.dev/cookbook ───────
/** Shows the pages as facing spreads on a dark desk: the first page is a
 *  recto on its own, then verso | recto pairs, as in a bound book. Pages
 *  are painted when they scroll near the screen. */
function showPages(docs, { title, width = 460 } = {}) {
  const root = viewer(title);
  const pages = [docs].flat().flatMap((doc) =>
    doc.pages.map((page) => ({ doc, page, n: (doc.pageIndexOffset ?? 0) + page.index })));
  const spreads = [];
  let verso = null;
  for (const p of pages) {
    if (p.n % 2 === 1) { if (verso) spreads.push([verso, null]); verso = p; }
    else { spreads.push([verso, p]); verso = null; }
  }
  if (verso) spreads.push([verso, null]);
  const density = Math.min(window.devicePixelRatio || 1, 2);
  showPages.painter?.disconnect();
  const painter = new IntersectionObserver((entries) => {
    for (const { isIntersecting, target } of entries) {
      if (!isIntersecting) continue;
      painter.unobserve(target);
      const { doc, page } = target.postext;
      renderPageToCanvas(page, doc, target, { scale: (width * density) / page.width });
    }
  }, { rootMargin: '800px' });
  showPages.painter = painter;
  root.replaceChildren(...spreads.map((pair) => {
    const spread = document.createElement('div');
    spread.className = 'pt-spread';
    for (const p of pair) {
      const figure = document.createElement('figure');
      if (p) {
        const label = p.page.pageLabel || String(p.n + 1);
        const canvas = document.createElement('canvas');
        canvas.postext = p;
        canvas.style.aspectRatio = `${p.page.width} / ${p.page.height}`;
        canvas.setAttribute('role', 'img');
        canvas.setAttribute('aria-label', `Page ${label}`);
        const folio = document.createElement('figcaption');
        folio.textContent = label;
        figure.append(canvas, folio);
        painter.observe(canvas);
      } else figure.className = 'pt-blank';
      spread.append(figure);
    }
    return spread;
  }));
  kitStatus(`${pages.length} ${pages.length === 1 ? 'page' : 'pages'}`);
  document.documentElement.dataset.postext = 'ready';
  return pages.length;
}

/** The desk, the bar and the error reporting, created once. */
function viewer(title) {
  if (!document.getElementById('pt-kit')) {
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit">
      :root { color-scheme: dark; }
      body { margin: 0; background: #0e1014; color: #b9bcc4; font: 13px/1.45 system-ui, sans-serif; }
      #pt-bar { position: sticky; top: 0; z-index: 1; display: flex; flex-wrap: wrap; align-items: center;
        gap: 6px 16px; padding: 10px 16px; background: rgb(14 16 20 / .92); backdrop-filter: blur(6px);
        border-bottom: 1px solid #23262d; }
      #pt-bar strong { color: #f4f1ea; font-weight: 600; }
      #pt-actions { display: flex; gap: 12px; margin-left: auto; }
      #pt-actions a, #pt-actions button { color: #d8a21a; font: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
      #pages { display: grid; justify-items: center; gap: 48px; padding: 32px 16px 72px; }
      .pt-spread { display: flex; }
      .pt-spread figure { margin: 0; width: min(460px, 44vw); }
      .pt-spread canvas { display: block; width: 100%; background: #fff;
        box-shadow: 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figure:first-child canvas { box-shadow: inset -14px 0 14px -14px rgb(0 0 0 / .18), 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figcaption { margin-top: 10px; text-align: center; font: 600 10px/1 system-ui, sans-serif;
        letter-spacing: .18em; text-transform: uppercase; color: #6c7079; }
      .pt-blank { visibility: hidden; }
      @media (max-width: 760px) {
        .pt-spread { flex-direction: column; gap: 32px; }
        .pt-spread figure { width: min(460px, 92vw); }
        .pt-blank { display: none; }
      }
    </style>`);
    document.body.insertAdjacentHTML('afterbegin',
      '<header id="pt-bar"><strong id="pt-title"></strong><span id="pt-status" role="status"></span><span id="pt-actions"></span></header>');
    document.getElementById('pt-title').textContent = document.title || 'Postext';
    addEventListener('error', (event) => kitFail(event.error ?? event.message));
    addEventListener('unhandledrejection', (event) => kitFail(event.reason));
  }
  if (title) document.getElementById('pt-title').textContent = title;
  return document.getElementById('pages')
    ?? document.body.appendChild(Object.assign(document.createElement('main'), { id: 'pages' }));
}

function kitStatus(text) {
  viewer();
  document.getElementById('pt-status').textContent = text;
}

function kitFail(error) {
  document.documentElement.dataset.postext = 'error';
  kitStatus(`Error: ${error?.message ?? error}`);
}

// ─── Kit · images v1 ── recipes with pictures · postext.dev/cookbook ──────────
/** Registers a photo or PNG for the canvas and keeps its bytes for the PDF.
 *  fetch → ImageBitmap never taints the canvas (a plain cross-origin <img> would). */
async function loadImage(fileId, url) {
  const res = await fetch(url);
  if (!res.ok) throw new Error(`Image not found (${res.status}): ${url}`);
  const bytes = new Uint8Array(await res.arrayBuffer());
  registerResourceImage(fileId, await createImageBitmap(new Blob([bytes])));
  (loadImage.bytes ??= new Map()).set(fileId, bytes);
}

/** Registers SVG markup (drawn in code, or fetched) as a vector image. */
async function loadSvg(fileId, svg) {
  const img = new Image();
  img.src = `data:image/svg+xml;charset=utf-8,${encodeURIComponent(svg)}`;
  await img.decode();
  registerResourceImage(fileId, img);
  (loadImage.bytes ??= new Map()).set(fileId, new TextEncoder().encode(svg));
}

/** renderToPdf({ resourceBytes: imageBytes }) */
function imageBytes(fileId) { return loadImage.bytes?.get(fileId); }

/** renderToHtml({ resourceImageUrl: imageUrl }) */
function imageUrl(fileId) {
  const bytes = imageBytes(fileId);
  if (!bytes) return undefined;
  imageUrl.urls ??= new Map();
  if (!imageUrl.urls.has(fileId)) {
    const type = /\.svg$/i.test(fileId) ? 'image/svg+xml' : /\.png$/i.test(fileId) ? 'image/png' : 'image/jpeg';
    imageUrl.urls.set(fileId, URL.createObjectURL(new Blob([bytes], { type })));
  }
  return imageUrl.urls.get(fileId);
}

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