figcraft/docs/translating.md

Translating FigCraft

FigCraft's interface strings live in one TOML catalog per language in crates/ui-egui/locales/. The build bakes every catalog into the binary (desktop and web); nothing is read at run time. Preferences ▸ Language picks the language and the interface switches at once. System takes the first of the OS's preferred languages that has a catalog (the browser's language on the web): a regional tag reads its language's catalog (fr-CA → fr), a language with only a regional catalog reads that one (pt-PT → pt-BR), and Latin American and US Spanish (es-MX, es-AR, es-CO, es-US, es-419…) read es-419. Chinese (zh, zh-CN, zh-SG, zh-Hans) reads zh-Hans; Traditional Chinese (zh-Hant, zh-TW, zh-HK, zh-MO) has no catalog and reads English (or the next OS language), not Simplified. pref.language {language} does the same from the CLI, MCP and the control channel.

The catalogs: English (en, the source), and Spanish (es, with the Latin American overlay es-419), French (fr), German (de), Brazilian Portuguese (pt-BR), Japanese (ja), Korean (ko) and Simplified Chinese (zh-Hans), machine-drafted and waiting for native speakers' review.

The catalogs

• en.toml lists every key. A key is the English text as the code writes it, so the code stays readable: tr("Fill"), trf("Delete {name}?", &[("name", &name)]), trn("{n} layers", count, &[]). Values equal their keys except plurals, which give both forms: "{n} layers" = { one = "{n} layer", other = "{n} layers" }.
• es.toml and other languages translate the same keys under [ui], plus command labels by command id under [commands] (the Actions palette, the shortcuts panel and the menus) and, under [menu], the few menu items the main menu words differently from the command (the Select matching submenu's "Fill" for "Select same fill"). Command ids, the CLI, MCP and control-channel output stay English.
• [meta] name is the language's own name (the picker shows it untranslated); [meta] status marks a draft (the Preferences window says so).
• A regional overlay (es-419.toml: a code with a region whose language has a catalog) lists only the entries worded differently there; everything else reads the language's catalog, then English. The check fails on an overlay entry that reads as in the catalog under it.

A key a catalog lacks shows its English text, so a partial catalog is safe to ship.

Typography follows each language: French puts a no-break space (\u00A0 in the TOML) before : ; ? !, inside « » and before %; German uses „ “ and formal address (Sie); Brazilian Portuguese uses Brazilian words (arquivo, salvar, tela, você), not European ones. Latin American Spanish overrides Spain's wording where it differs (agregar, presionar, configuración for settings, Enter for the key, control for a gamepad, resorte) and keeps Spanish's tú. Japanese is concise, without です/ます endings, with full-width （）「」：、。 where Japanese UI text has them; Korean labels end without 합니다 (instructions in -세요). Simplified Chinese is concise, with full-width （）：，、。“” in Chinese text and a space between Chinese and Latin words or numbers. None of the three has plural forms.

CJK text needs a CJK font, which egui and Inter lack: the desktop app adds an installed one when something on screen needs it (see crates/ui-egui/src/cjk.rs). The web build has no system fonts, so Japanese, Korean and Chinese appear there only in a build with craft-fonts and FIGCRAFT_EMBED_CJK=1 (Noto Sans CJK SC, +16 MB); otherwise they are left out of the picker. A Chinese UI puts its Chinese face first so Han takes Simplified Chinese shapes. A new CJK or other non-Latin language also needs its script in cjk::language.

Adding a language

1. Copy crates/ui-egui/locales/es.toml to <code>.toml (a BCP 47 code: fr, pt-BR, ja) and set [meta] name and status = "draft — needs native review".

2. Translate every value; keep the keys. Keep {placeholders} exactly, "…" where English has it, brand names and keyboard glyphs. English labels of commands: figcraft-cli commands.

3. Plurals: give one only if the language has a singular form (Japanese, Korean and Chinese give only other, and plural_one returns false for them). trn picks one for a count of 1, and also for 0 in French and Brazilian Portuguese (keep {n} in their one forms); a language with other rules needs its rule in plural_one in crates/ui-egui/src/i18n.rs.

4. To require full coverage, add the code to COMPLETE in crates/ui-egui/src/i18n_tests.rs. Every later PR that adds a string then has to translate it into each complete language, so only Spanish is there: French, German, Brazilian Portuguese, Japanese, Korean and Simplified Chinese are registered as drafts, and a string added later shows English in them until it is translated. To list what a draft lacks, add its code to COMPLETE locally and run the check.

5. Run the check and look at the panels in the app (longer words must fit the right panel):

   cargo test -p figcraft-ui-egui i18n
   

   Dropdowns, the right panel's two-column labels and the home cards cut a label that doesn't fit with "…" and show it in full on hover; elsewhere, look for clipped or wrapped text.

The check fails on keys the code uses that en.toml lacks (it prints the lines to paste), keys no code uses, unknown command ids, placeholders that don't match English, and, for complete languages, anything untranslated. Machine-drafted catalogs stay marked as drafts until a native speaker has reviewed them.

Adding strings in code

Wrap every string a user sees or a screen reader hears: tr for plain text, trf for {named} placeholders, trn for counts, tr_noop for literals in const tables that are looked up later with tr(label). The key must be a string literal as the first argument (the check reads the source). Don't wrap ids, command ids, JSON, log messages, file extensions or document content. Then add the key to en.toml and to each complete language (Spanish); the drafts may follow later.

Labels from the engine and document crates (tool names, blend modes, easing curves…) are looked up at display with tr(x.label()); they are listed in dynamic_labels in i18n_tests.rs.