egui: load locale language on startup

Cargo.toml

@@ -19,7 +19,7 @@ required-features = ["egui"]
 [features]
 default = ["disable_contracts"]
 cli = ["dep:clap"]
-egui = ["dep:eframe", "dep:egui", "dep:rfd", "dep:futures"]
+egui = ["dep:sys-locale", "dep:unic-langid", "dep:fluent-templates", "dep:eframe", "dep:egui", "dep:rfd", "dep:futures"]
 disable_contracts = ["contracts/disable_contracts"]
 
 [dependencies]
@@ -35,7 +35,6 @@ contracts = "0.6.3"
 bimap = "0.6.3"
 log = "0.4"
 utf8-chars = "3.0.2"
-fluent-templates = "0.9.4"
 
 [dependencies.specctra_derive]
 path = "macro/specctra_derive"
@@ -53,6 +52,19 @@ optional = true
 version = "4.5.8"
 features = ["derive"]
 
+[dependencies.sys-locale]
+optional = true
+version = "0.3.1"
+
+[dependencies.unic-langid]
+optional = true
+version = "0.9.5"
+features = ["macros", "serde"]
+
+[dependencies.fluent-templates]
+optional = true
+version = "0.9.4"
+
 [dependencies.eframe]
 optional = true
 version = "0.26.0"

locales/core.ftl

@@ -1 +0,0 @@
--something = foo

src/bin/topola-egui/app.rs

@@ -10,6 +10,7 @@ use std::{
         Arc, Mutex,
     },
 };
+use unic_langid::{langid, LanguageIdentifier};
 
 use topola::{
     autorouter::{
@@ -49,6 +50,8 @@ use crate::{
 #[derive(Serialize, Deserialize)]
 #[serde(default)]
 pub struct App {
+    langid: LanguageIdentifier,
+
     #[serde(skip)]
     maybe_overlay: Option<Overlay>,
 
@@ -86,6 +89,7 @@ pub struct App {
 impl Default for App {
     fn default() -> Self {
         Self {
+            langid: langid!("en-US"),
             maybe_overlay: None,
             arc_mutex_maybe_invoker: Arc::new(Mutex::new(None)),
             maybe_execute: None,
@@ -103,13 +107,20 @@ impl Default for App {
 
 impl App {
     /// Called once on start.
-    pub fn new(cc: &eframe::CreationContext<'_>) -> Self {
+    pub fn new(cc: &eframe::CreationContext<'_>, langid: LanguageIdentifier) -> Self {
         // Load previous app state if one exists.
         if let Some(storage) = cc.storage {
-            return eframe::get_value(storage, eframe::APP_KEY).unwrap_or_default();
+            let this = Self {
+                langid,
+                ..eframe::get_value(storage, eframe::APP_KEY).unwrap_or_default()
+            };
+            return this;
         }
 
-        Default::default()
+        Self {
+            langid,
+            ..Default::default()
+        }
     }
 
     fn update_state(&mut self, dt: f32) {

src/bin/topola-egui/main.rs

@@ -12,12 +12,13 @@ mod top;
 mod viewport;
 use app::App;
 use fluent_templates::static_loader;
+use sys_locale::get_locale;
+use unic_langid::{langid, LanguageIdentifier};
 
 static_loader! {
     static LOCALES = {
         locales: "./locales",
         fallback_language: "en-US",
-        core_locales: "./locales/core.ftl",
     };
 }
 
@@ -25,6 +26,11 @@ static_loader! {
 #[cfg(not(target_arch = "wasm32"))]
 fn main() -> eframe::Result<()> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
+    let langid = if let Some(langname) = get_locale() {
+        langname.parse().unwrap_or(langid!("en-US"))
+    } else {
+        langid!("en-US")
+    };
 
     let native_options = eframe::NativeOptions {
         viewport: egui::ViewportBuilder::default()
@@ -35,7 +41,7 @@ fn main() -> eframe::Result<()> {
     eframe::run_native(
         "topola-egui",
         native_options,
-        Box::new(|cc| Box::new(App::new(cc))),
+        Box::new(|cc| Box::new(App::new(cc, langid))),
     )
 }
 
@@ -46,13 +52,14 @@ fn main() {
     eframe::WebLogger::init(log::LevelFilter::Debug).ok();
 
     let web_options = eframe::WebOptions::default();
+    let langid: LanguageIdentifier = "en-US".parse();
 
     wasm_bindgen_futures::spawn_local(async {
         eframe::WebRunner::new()
             .start(
                 "topola-egui",
                 web_options,
-                Box::new(|cc| Box::new(App::new(cc))),
+                Box::new(|cc| Box::new(App::new(cc, langid))),
             )
             .await
             .expect("failed to start eframe");

src/bin/topola/main.rs

@@ -11,14 +11,6 @@ use topola::autorouter::selection::PinSelection;
 use topola::autorouter::Autorouter;
 use topola::specctra::design::SpecctraDesign;
 
-static_loader! {
-    static LOCALES = {
-        locales: "./locales",
-        fallback_language: "en-US",
-        core_locales: "./locales/core.ftl",
-    };
-}
-
 #[derive(Parser, Debug, Default)]
 #[command(about, version)]
 struct Cli {