# Erudit — site icons + Open Graph card

The favicon set and the `og:image` link-preview card for the public landing
(`ui/landing.html`) and the SPA shell (`ui/index.html`). Same design language as the
[VK loading-screen logo](../vk/README.md): the wooden Erudit «Э» tile (score `8`),
with the wordmark on the app's dark board green (`ui/src/app.css` tokens).

| Output (committed to `ui/public/`) | Purpose |
|------|---------|
| `favicon.svg` | Vector favicon, transparent; tile + «Э» only (the score is illegible below ~32 px). |
| `favicon.ico` | 32×32 PNG-in-ICO fallback (also answers the browsers' blind `/favicon.ico` probe). |
| `apple-touch-icon.png` | 180×180 opaque full-bleed tile; iOS masks its own corners. |
| `og-image.png` | 1200×630 card: tile + «Эрудит / Скрэббл — игра в слова». Referenced absolutely as `https://erudit-game.ru/og-image.png`. |

## How it works

`build/extract.js` extracts the needed glyph outlines (tile glyphs + every wordmark
character) from LiberationSans (Arial-metric, the game's font stack) with their
advance widths into `build/glyphs.json` (committed). `build/generate.js` composes
plain SVG from those outlines — no font is needed at generation time — writes
`favicon.svg` and rasterises the PNG/ICO outputs by screenshotting the SVGs with the
`ui` package's Playwright chromium (`@playwright/test`); the `.ico` container is
assembled in-script (a single PNG entry). Raster bytes therefore depend on the
installed chromium version; the SVG sources are deterministic.

## Regenerate

Requirements: Node ≥ 18, `ui` installed (`pnpm install`, provides Playwright).
`extract.js` additionally needs `opentype.js` (`npm i opentype.js`); **`generate.js`
needs no extra packages**.

```sh
cd assets/icons

# 1. (optional) re-extract the glyphs — only if the font or the wordmark changes:
#    default font: /usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf
node build/extract.js [/path/to/font.ttf]      # -> build/glyphs.json

# 2. regenerate everything in ui/public/:
node build/generate.js
```