gridcraft/docs/localization-parity.md

Localization parity

Last reviewed: 2026-10-10 · Last updated: 2026-10-12 · Change: minor (Format Cells dialog looks its labels up in the catalog) · Target: Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4

Per-language status against Excel, which ships its UI in dozens of languages (Windows language packs cover 100+), with localized function names, argument separators, number and date formats, right-to-left sheets and full complex-script support. Part of target-app-parity.md. Localization: ~10% ready, 100–165 h (estimated).

Where we are (measured from source on main, after the 2026-10-10 merges)

• A first catalog exists, for the ribbon only. crates/ui-egui/src/i18n.rs (merged 10-10 in #31, #104, #82; German added 10-11) adds an interface-language preference that defaults to the system language (closes #20) and a View-tab switcher, with English-keyed lookup tables: Japanese 268 labels, Simplified Chinese, Korean, Russian, Brazilian Portuguese, German and Czech 266 each. The tables are used by the ribbon, sheet tabs and widgets (ribbon.rs, tabs.rs, widgets.rs), the Format Cells dialog, every dialog title and the shared OK/Cancel buttons; the other dialogs, menus, context menus, task panes, status messages, command labels and function descriptions are still English literals. Untranslated labels fall back to English.
• About 2,200 user-visible strings in all (heuristic source scan: ~1,700 UI and command strings plus ~500 function descriptions), so each shipped language covers ~12% (measured count / estimated total).
• en-US only formulas and formats. Function names, , argument separator, . decimal separator, en-US number and date formats (crates/numfmt says "en-US only"). Users ask for localized function names and ; separators (#45). German with localized numbers and formulas is in PR #163 (open).
• Script support. System-font fallback for CJK, Thai and Hebrew landed in #38 (closes #32; #142 is still open pending confirmation). There is no complex-text shaping: Arabic and Devanagari don't join or reorder, and there is no bidirectional layout. Sheet Right-to-Left (view.rightToLeft, Page Layout › Sheet Options, XLSX rightToLeft) mirrors the grid (#146): column A and the row headers on the right, the vertical scrollbar on the left; hit-testing, arrow keys, editor, popups and floating objects follow; text stays left-to-right inside its box (no bidi), and the sheet tabs, horizontal scrollbar and printing/PDF are not mirrored yet. IME input goes through egui/winit and is unverified for Chinese, Japanese and Korean.
• PDF export uses only the 14 standard PDF fonts: non-Latin text cannot export.

Languages

UI strings translated are measured counts against the ~2,200 estimate. Estimates to full include the rest of the catalog work below (10–20 h, counted once), localized function names, separators, number/date formats, machine translation with agent review, and script work.

Language	Code	UI strings translated	Dialogs / tooltips / help	Script support	Native review	Status	Estimate to full
English	en	~2,200 / ~2,200 (100%, source)	yes	Latin: yes	yes	full	—
Simplified Chinese (Mandarin)	zh-Hans	266 (~12%)	no	CJK system-font fallback (#38); IME unverified; PDF can't export	no	menus only	8–13 h
Spanish	es	0 (0%)	no	Latin: yes	no	none	6–10 h
Hindi	hi	0 (0%)	no	Devanagari: no shaping	no	none	12–18 h
Arabic	ar	0 (0%)	no	no shaping, no RTL UI; Sheet Right-to-Left mirrors the grid (#146)	no	none	25–35 h
French	fr	0 (0%)	no	Latin: yes	no	none	6–10 h
Portuguese	pt-BR	923 (~42%)	dialogs and tooltips (dialogs take effect with #669)	Latin: yes	no	menus, File view, dialogs	2–4 h
Indonesian	id	0 (0%)	no	Latin: yes	no	none	5–8 h
Japanese	ja	268 (~12%)	no	CJK system-font fallback; IME unverified; no furigana display	no	menus only	8–12 h
German	de	266 (~12%)	no	Latin: yes	no	menus only	4–8 h
Korean	ko	266 (~12%)	no	Hangul via the CJK fallback; IME unverified	no	menus only	6–10 h
Vietnamese	vi	0 (0%)	no	Latin with stacked diacritics: unverified	no	none	6–10 h

Other shipped languages: Russian (ru) and German (de), 266 labels each (~12%), menus only.

Total: catalog work 10–20 h + languages 92–144 h ≈ 100–165 h. Parallelizes almost fully once the catalog covers dialogs and commands. Needs a human: native-speaker review of every language (none so far) and of localized function names.

Infrastructure (do first)

1. Extend the catalog from the ribbon to every user-visible string (dialogs, menus, task panes, status and error messages, command labels, function descriptions), with a missing-key check in cargo xtask ci. Language switching and the system-language default already exist (#31).
2. Locale-aware formulas: localized function-name tables and separators at the formula-bar boundary only (files keep en-US invariant names), locale number and date formats, list separators in CSV.
3. Text shaping and fallback: a shaping engine for grid, editor and PDF text (Arabic, Devanagari, Thai), system font fallback for CJK, bidirectional runs, right-to-left sheet tabs and printing; embedded subset fonts in PDF.

Revision history

Date	Change	Summary
2026-10-12	minor	Format Cells looks up its tabs, labels, options and note through Language::tr (Fill tab keyed Format Cells|Fill); dialog titles and OK/Cancel too. Labels already in a table (Number, Currency, Fill…) show translated; the rest fall back to English until the tables add them
2026-10-12	minor	Brazilian Portuguese catalog (i18n/pt.rs) grows from 377 to 923 entries: every key the other catalogs translate, including the dialog strings #669 starts looking up (~42%)
2026-10-11	minor	German ribbon catalog (i18n/de.rs, 266 labels, ~12%); de locale tags (de-DE, de-AT, de-CH…) resolve to German. PR #163 (localized German formulas/numbers) still open
2026-10-11	minor	Sheet Right-to-Left mirrors the grid (#146)
2026-10-11	minor	Czech (cs) ribbon table: 266 labels (~12%), menus only
2026-10-10	minor	Re-measured after #31, #104, #82, #38 merged: ribbon translated into ja, zh, ko, pt-BR and ru (266–268 labels, ~12%), system-language default, CJK/Thai/Hebrew font fallback; ~10% ready, 100–165 h
2026-10-10	major	Created: English only, no catalog, ~2,200 strings, script-support gaps, open language PRs