erf(i18n): cache translations and skip unnecessary bidi analysis

tr() uses a OnceLock<HashMap>, initialized once, changing lookups from a linear scan to average O(1).
Labels without RTL text, such as Chinese, Japanese, and Western-language labels, skip BidiInfo. Arabic, Hebrew, and directional controls retain their existing handling.

crates/ui-egui/src/i18n.rs

@@ -3,6 +3,8 @@
 //! Chinese and Arabic feature terminology is checked against public Adobe help where documented;
 //! project-specific labels are original. Sources and scope: `docs/localization-terminology.json`.
 
+use std::{collections::HashMap, sync::OnceLock};
+
 mod ar;
 
 /// Supported interface languages: (code, name in that language).
@@ -2635,14 +2637,13 @@ fn column(lang: &str) -> Option<usize> {
 
 /// `s` in `lang` (English, or the string itself, when there's no translation).
 pub fn tr<'a>(lang: &str, s: &'a str) -> &'a str {
+    static TRANSLATIONS: OnceLock<HashMap<&'static str, [&'static str; 5]>> = OnceLock::new();
+    static ARABIC: OnceLock<HashMap<&'static str, &'static str>> = OnceLock::new();
     if lang == "ar" {
-        return ar::TABLE.iter().find(|(en, _)| *en == s).map_or(s, |(_, t)| *t);
+        return ARABIC.get_or_init(|| ar::TABLE.iter().copied().collect()).get(s).copied().unwrap_or(s);
     }
     let Some(c) = column(lang) else { return s };
-    match TABLE.iter().find(|(en, _)| *en == s) {
-        Some((_, t)) => t[c],
-        None => s,
-    }
+    TRANSLATIONS.get_or_init(|| TABLE.iter().copied().collect()).get(s).and_then(|row| row.get(c)).copied().unwrap_or(s)
 }
 
 /// Localize reserved built-in style names only; user-defined names are document data.
@@ -2665,6 +2666,23 @@ pub fn workspace_name<'a>(lang: &str, name: &'a str) -> &'a str {
 mod tests {
     use super::*;
 
+    #[test]
+    fn cached_lookup_preserves_every_translation_across_language_switches() {
+        for (key, translations) in TABLE {
+            for (lang, expected) in ["de", "fr", "es", "ja", "zh"].into_iter().zip(translations) {
+                assert_eq!(tr(lang, key), *expected, "{lang}: {key}");
+            }
+            assert_eq!(tr("", key), *key);
+        }
+        for (key, expected) in ar::TABLE {
+            assert_eq!(tr("ar", key), *expected, "ar: {key}");
+        }
+        let unknown = String::from("A user-defined untranslated label");
+        for lang in ["ar", "zh", "ja", "de", "fr", "es", "", "unknown"] {
+            assert!(std::ptr::eq(tr(lang, &unknown), unknown.as_str()));
+        }
+    }
+
     #[test]
     fn translates_known_strings_and_keeps_the_rest() {
         assert_eq!(tr("de", "File"), "Datei");

crates/ui-egui/src/rtl.rs

@@ -3,13 +3,40 @@
 use egui::text::{LayoutJob, TextWrapping};
 use egui::{Align, Align2, Color32, FontFamily, FontId, Galley, Pos2, Rect, WidgetText};
 use std::{ops::Range, sync::Arc};
-use unicode_bidi::BidiInfo;
+use unicode_bidi::{BidiClass, BidiInfo, bidi_class};
 use unicode_segmentation::UnicodeSegmentation;
 
+/// Allocation-free preflight: ordinary Latin, CJK and emoji labels need no bidi analysis.
+/// Include directional controls so explicit embeddings/overrides keep their existing behavior.
+fn may_have_rtl(text: &str) -> bool {
+    !text.is_ascii()
+        && text.chars().any(|c| {
+            matches!(
+                bidi_class(c),
+                BidiClass::R
+                    | BidiClass::AL
+                    | BidiClass::AN
+                    | BidiClass::LRE
+                    | BidiClass::RLE
+                    | BidiClass::LRO
+                    | BidiClass::RLO
+                    | BidiClass::PDF
+                    | BidiClass::LRI
+                    | BidiClass::RLI
+                    | BidiClass::FSI
+                    | BidiClass::PDI
+            )
+        })
+}
+
+fn has_rtl(text: &str) -> bool {
+    may_have_rtl(text) && BidiInfo::new(text, None).has_rtl()
+}
+
 /// Resolve translated labels through bidi, without changing IDs, commands or stored text.
 pub fn widget(ui: &egui::Ui, text: impl Into<WidgetText>) -> WidgetText {
     let text = text.into();
-    if text.text().is_ascii() || !BidiInfo::new(text.text(), None).has_rtl() {
+    if !has_rtl(text.text()) {
         return text;
     }
     let mut job = (*text.into_layout_job(ui.style(), egui::FontSelection::Default, Align::Center)).clone();
@@ -21,7 +48,7 @@ pub fn widget(ui: &egui::Ui, text: impl Into<WidgetText>) -> WidgetText {
 /// Accessibility still receives the original logical string through Galley::job.
 pub fn label(ui: &mut egui::Ui, text: impl Into<WidgetText>) -> egui::Response {
     let text = text.into();
-    let rtl = !text.text().is_ascii() && BidiInfo::new(text.text(), None).has_rtl();
+    let rtl = has_rtl(text.text());
     if !rtl {
         return ui.label(text);
     }
@@ -112,7 +139,7 @@ fn visual_line(job: &LayoutJob, bidi: &BidiInfo<'_>, line: Range<usize>) -> Layo
 }
 
 fn layout(ctx: &egui::Context, mut job: LayoutJob) -> Arc<Galley> {
-    if job.text.is_ascii() || !BidiInfo::new(&job.text, None).has_rtl() {
+    if !has_rtl(&job.text) {
         return ctx.fonts_mut(|fonts| fonts.layout_job(job));
     }
     let original = Arc::new(job.clone());
@@ -219,6 +246,32 @@ mod tests {
         galley.rows.iter().flat_map(|row| row.glyphs.iter().filter(|g| g.advance_width > 0.0).map(|g| g.chr)).collect()
     }
 
+    #[test]
+    fn ordinary_multilingual_labels_skip_bidi_analysis() {
+        for text in ["", "File (123)", "Édition", "中文排版", "スウォッチ", "e\u{301}", "🎨 🙂"] {
+            assert!(!may_have_rtl(text), "{text:?}");
+            assert!(!BidiInfo::new(text, None).has_rtl(), "{text:?}");
+        }
+        for text in ["ملف", "עברית", "PDF ملف 123", "\u{1e900}", "\u{200f}", "\u{202e}abc\u{202c}", "\u{2067}abc\u{2069}", "١٢٣"] {
+            assert!(may_have_rtl(text), "{text:?}");
+            assert_eq!(has_rtl(text), BidiInfo::new(text, None).has_rtl(), "{text:?}");
+        }
+    }
+
+    #[test]
+    fn non_rtl_widgets_keep_native_text_and_formatting() {
+        with_fonts(|ctx| {
+            egui::Area::new(egui::Id::new("rtl-fast-path-test")).show(ctx, |ui| {
+                for text in ["中文", "日本語", "Édition", "🎨"] {
+                    let rendered = widget(ui, egui::RichText::new(text).strong());
+                    assert!(matches!(rendered, WidgetText::RichText(_)));
+                    assert_eq!(rendered.text(), text);
+                    assert!(label(ui, text).rect.is_finite());
+                }
+            });
+        });
+    }
+
     #[test]
     fn mixed_arabic_latin_digits_and_brackets_preserve_logical_source() {
         with_fonts(|ctx| {