gridcraft/docs/localization-parity.md

Localization parity

Last reviewed: 2026-10-10 · Last updated: 2026-10-27 · Change: minor (Arabic font fallback; missing translations are listed by cargo xtask i18n-report and never fail a check); previously minor (number formats honour the B1/B2 calendar prefixes, checked against Excel; earlier: missing translations are listed by cargo xtask i18n-report and never fail a check; Arabic text sorts by its letters, not its vowel marks); previously minor (AutoFit estimates Arabic text width from measured glyph widths); previously minor (missing translations are listed by cargo xtask i18n-report and never fail a check; Arabic text sorts by its letters, not its vowel marks) · 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 and command labels are still English literals. Untranslated labels fall back to English.
• Function help (the argument hint, autocomplete, Insert Function and the Formulas-tab menus) follows the interface language through per-language tables keyed by the catalog's English text (i18n/<lang>_functions.rs): descriptions, and argument names from which the hint is assembled with the formula syntax's function name and separator. Spanish translates the 10 common functions it had help for (SUM, AVERAGE, IF…); other languages show the English help.
• A first catalog exists. 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: Simplified Chinese, Korean, Russian, German and Czech 266–518 labels each, Brazilian Portuguese and Japanese 943 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; Japanese and Portuguese also cover the other dialog labels, message boxes, Backstage/File-view items, template names and native menus (Japanese, 10-17: i18n/ja.rs keeps the shared 398-label core and adds 545 of those strings). The remaining 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 the ribbon-only languages cover ~12% and Japanese and Portuguese ~43% (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). The B1 (Gregorian) and B2 (Hijri) calendar prefixes that Arabic Excel writes at the start of a format section are hidden; under B2 the year, month number, day, month names and weekday names (Arabic; mmm and ddd show the full name) count in the tabular Hijri calendar (leap years 2, 5, 7, 10, 13, 15, 18, 21, 24, 26 and 29 of each 30-year cycle). Checked against Excel 16.0 (build 20527, en-US) on every serial from 1 to 2,958,465 and about 1,700 format/value pairs: a [$...] locale or currency tag before B2 keeps the date Gregorian; a repeated prefix (B2B2) is accepted; any other B and digit (B3, B12, B1B2, dd B2, \B2), or a prefix before a number format (B10.00), is rejected (TEXT gives #VALUE!, a cell shows General); serial 60 shows #VALUE! under B2 for any date or clock part; two-word month names use a no-break space. Differs from Excel: in a B2 section with a weekday and a month name, Excel prints the weekday for mmmm/mmmmm after ddd/dddd, and the weekday numbered by the month (Saturday from month 7) for ddd/dddd after mmm/mmmm; a B2 section showing only the weekday uses the real weekday for serials 0–59 and gives #VALUE! for the last days of 9999. Excel's Buddhist-year b/bb/bbbb tokens are not supported.
• Script support. System-font fallback for CJK, Thai and Hebrew landed in #38 (closes #32; #142 is still open pending confirmation). Native CJK fallback also probes Flatpak's read-only /run/host/fonts, /run/host/local-fonts and /run/host/user-fonts layouts, so installed Noto CJK and WenQuanYi faces can render Chinese without a broad filesystem grant. This does not change the installed-font catalogue or add bundled fonts. Lao falls back to Lao Sangam MN / Lao MN (macOS), Leelawadee UI / DokChampa (Windows) or Noto Sans Lao / Phetsarath OT (Linux). Arabic falls back to a system Arabic face, fontconfig's Arabic choice or craft-fonts' Noto Sans Arabic; fontconfig's choice leads these fallbacks, but a UI font with Arabic of its own (DejaVu Sans in the Flatpak) still draws interface Arabic (#229). 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, .xls WINDOW2 fRightToLeft) 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. Text boxes and shapes keep their paragraphs' right-to-left direction (a:pPr rtl) through XLSX save, though GridCraft still draws that text left to right. IME input goes through egui/winit and is unverified for Chinese, Japanese and Korean.
• Names in any script. Defined names (Define Name, Create from Selection) are limited to 255 characters, counted as characters rather than UTF-8 bytes, so a 255-letter Arabic name is accepted as in Excel. Sheet names already counted characters (31).
• 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	943 (~43%)	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, but phonetic runs (ふりがな) survive an XLSX open + save	no	menus only	8–12 h
Japanese	ja	943 (~43%)	dialogs and messages	CJK system-font fallback; IME unverified; no furigana display	no	menus, File view, dialogs, messages	3–5 h
Japanese	ja	268 (~12%)	no	CJK system-font fallback; the theme's East Asian typeface (<a:ea>) survives open + save (rendering does not use it yet); IME unverified; no furigana display	no	menus only	8–12 h
German	de	266 (~12%)	no	Latin: yes	no	menus only	4–8 h
Italian	it	971 (~44%)	dialogs, tooltips, pivot pane	Latin: yes	no	menus, File view, dialogs, pivot pane	3–5 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
Turkish	tr	382 (~17%)	no	Latin: yes	yes	menus only	4–8 h

Other shipped languages: Russian (ru), German (de), Czech (cs), French (fr) and Turkish (tr), menus only. | Vietnamese | vi | 398 (~18%) | no | Latin with stacked diacritics: unverified | no | menus, File view | 5–9 h | Other shipped languages: Russian (ru) and German (de), 266 labels each (~12%), menus only; Dutch (nl), 518 labels (~24%): ribbon, context menus, File view, dialog titles and the Options page.

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). A string a catalog lacks shows in English and never fails a check: cargo xtask i18n-report lists the missing strings per language, and cargo xtask ci runs it first. 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
2026-10-26	minor	Arabic text renders in cells and the interface: a system Arabic face (Tahoma, Arial or Segoe UI on Windows, Geeza Pro on macOS, Noto Sans or Naskh Arabic on Linux) joins the script fallbacks, fontconfig's Arabic choice, when it has Arabic letters, leads the Arabic fallbacks and draws Arabic wherever the UI or cell font has none, such as the default cell fonts (part of #229; a UI font with Arabic of its own, such as DejaVu Sans in the Flatpak, still draws interface Arabic, left for a follow-up), and craft-fonts' Noto Sans Arabic is a required face allowed on the web. Workbook fonts without Arabic keep every script fallback. Shaping and bidirectional layout remain separate work
2026-10-27	minor	Number formats honour the B1/B2 calendar prefixes: never shown; B2 renders year, month, day and Arabic month and weekday names in the tabular Hijri calendar (1 Jan 2001 = 6 Shawwal 1421; leap years 2, 5, 7, 10, 13, 15, 18, 21, 24, 26 and 29 of the 30-year cycle, which is what Excel shows). Checked against Excel 16.0 (build 20527, en-US) on every serial and about 1,700 format/value pairs: a locale or currency tag before B2 keeps the date Gregorian, a misplaced B and digit or a prefix before a number format is rejected, serial 60 has no Hijri date, serial 0 shows as serial 1, two-word month names use a no-break space. Not matched: Excel's weekday/month-name mix-ups in one B2 section and its weekday-only quirks
2026-10-27	minor	AutoFit column width, wrapped-row height and PivotTable column fit estimate Arabic letters at ~0.48 em (measured 0.36–0.53 em shaped, Noto Sans/Naskh Arabic and DejaVu Sans) instead of 1 em, Arabic-Indic digits as wide as ASCII digits, and give vowel marks and direction marks no width; vowelled Arabic no longer fits ~3.5× too wide
2026-10-23	minor	Missing translations are reported, never a failure: cargo xtask i18n-report prints, per language, the strings other catalogs translate and it lacks (plus Spanish function help rows keyed by English the function catalog no longer has) and always passes; cargo xtask ci runs it first. Coverage and per-language parity tests and tests of one language's exact wording are gone; UI tests take the expected text from the catalog. Duplicate-key, placeholder, context-prefix and line-shape checks stay
2026-10-21	minor	Romanian interface (ro, Română): 970 labels covering every key of the other catalogs (crates/ui-egui/src/i18n/ro.rs), ro-* system locales, the View-tab switcher and app.language.set; context keys show no prefix (File › Options test). English formulas and formats; AI-assisted draft pending native-speaker review
2026-10-20	minor	Japanese: furigana (rPh phonetic runs and <phoneticPr> in xl/sharedStrings.xml) is no longer deleted by an open + save; it is kept on the workbook and written back (a <phoneticPr> without runs is kept too, while duplicate texts with different readings keep only the first, reported on open). Display of the readings is still missing (crates/xlsx/src/tests/phonetic_tests.rs)
2026-10-20	minor	Japanese catalog (i18n/ja.rs) covers every key the Brazilian Portuguese catalog translates: the 398-label shared core moved verbatim plus 545 dialog, message, Backstage and menu strings — 943 keys, ~12% → ~43%. A test parses pt.rs's source, so the two catalogs can't drift apart again. Portuguese re-measured at 943 (was 923)
2026-10-20	minor	Dutch (nl) interface catalog (i18n/nl.rs, 518 labels, ~24%): the shared key set every language must cover (ribbon, context menus, File view, dialog titles, Options page), matching the German, French and Czech catalogs; nl-NL, nl-BE locale tags resolve to Dutch
2026-10-20	minor	XLSX: a theme's per-script typefaces (<a:font script="Arab">, Hebr, Jpan…) are kept through open + save, so Arabic Excel's theme fonts for shapes, charts and theme-font cells survive a GridCraft save
2026-10-20	trivial	XLSX: a workbook theme's major/minor East Asian (<a:ea>) and complex-script (<a:cs>) typefaces are kept through open + save, so a Japanese workbook keeps its theme's East Asian font; rendering does not resolve them yet (follow-up)
2026-10-19	minor	Text order (Sort, SORT/SORTBY, </>, approximate MATCH/XLOOKUP, "<x" criteria) compares letters first: Arabic vowel and Quranic marks, tatweel and invisible format characters (bidi marks, embeddings and isolates, ZWJ/ZWNJ, BOM, soft hyphen) no longer decide where text sorts, and Arabic-Indic digits sort as digits. Text with the same letters then sorts letter by letter, unmarked before marked, marks in Excel's order (sukun before shadda) and digits ASCII, Arabic-Indic, Extended Arabic-Indic; checked against Excel 16.0 build 20527 (en-US). Equality is unchanged
2026-10-19	minor	XLSX fonts retain charset and family metadata so systems can select a substitute font with the intended script when the named font is unavailable
2026-10-19	minor	Arabic CSV and text imports decode Windows-1256 text; Arabic shaping and bidirectional UI remain unsupported
2026-10-19	minor	Defined-name length counts characters, not bytes: Arabic names up to 255 letters are accepted, and Create from Selection keeps long Arabic headers
2026-10-19	minor	Table names are limited to 255 Unicode characters
2026-10-19	minor	Right-to-left sheets in legacy .xls files (common in older Arabic workbooks) open right-to-left
2026-10-19	trivial	Text boxes and shapes keep right-to-left paragraph direction (a:pPr rtl) on XLSX save, so Excel-authored Arabic and Hebrew text boxes reopen right to left
2026-10-19	minor	Save as Web Page and copied HTML mark right-to-left sheets dir="rtl", let General-aligned Arabic and Hebrew text align by its own direction (dir="auto"), and keep numbers on right-to-left sheets left to right and on the left
2026-10-19	minor	French and Serbian kept the context in three context|label translations ("Options|Général", "Opcije|Opšte" for Options|General; also Options|Save, Sheet Options|View). tr shows a found translation as it is, so File › Options headings and the Sheet Options "View" checkboxes showed the prefix. Fixed; a test checks that no catalog shows a |
2026-10-17	minor	Vietnamese catalog (i18n/vi.rs, every key in the master table); vi locale tags resolve to Vietnamese
2026-10-17	minor	Lao text falls back to an installed Lao face (sys-lao) instead of tofu boxes
2026-10-15	minor	Function help in the interface language: argument hints, autocomplete, Insert Function (search, categories) and the Formulas-tab menus read per-language tables of descriptions and argument names keyed by the catalog's English text; Spanish keeps its 10 functions in the new format
2026-10-15	minor	Italian catalog (i18n/it.rs, 971 entries, ~44%): every key the Brazilian Portuguese catalog translates plus the PivotTable Fields pane strings; it locale tags (it-IT, it-CH…) resolve to Italian. Labels follow Excel's Italian terminology; native-speaker review still pending
2026-10-14	minor	CJK fallback probes the read-only Flatpak host font mounts with the existing distribution layouts and TTC locale indices; no new sandbox permissions or bundled fonts
2026-10-12	minor	Turkish ribbon catalog (i18n/tr.rs, 382 labels); tr locale tags (tr-TR, tr_TR…) resolve to Turkish
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