Qt: Implement 'System Language' language option

src/core/fullscreen_ui.cpp

@@ -4097,18 +4097,13 @@ void FullscreenUI::DrawInterfaceSettingsPage()
     // Have to do this the annoying way, because it's host-derived.
     const auto language_list = Host::GetAvailableLanguageList();
     TinyString current_language = bsi->GetTinyStringValue("Main", "Language", "");
-    const char* current_language_name = "Unknown";
-    for (const auto& [language, code] : language_list)
-    {
-      if (current_language == code)
-        current_language_name = language;
-    }
     if (MenuButtonWithValue(FSUI_ICONVSTR(ICON_FA_LANGUAGE, "Language"),
-                            FSUI_VSTR("Chooses the language used for UI elements."), current_language_name))
+                            FSUI_VSTR("Chooses the language used for UI elements."),
+                            Host::GetLanguageName(current_language)))
     {
       ImGuiFullscreen::ChoiceDialogOptions options;
       for (const auto& [language, code] : language_list)
-        options.emplace_back(fmt::format("{} [{}]", language, code), (current_language == code));
+        options.emplace_back(Host::GetLanguageName(code), (current_language == code));
       OpenChoiceDialog(FSUI_ICONVSTR(ICON_FA_LANGUAGE, "UI Language"), false, std::move(options),
                        [language_list](s32 index, const std::string& title, bool checked) {
                          if (static_cast<u32>(index) >= language_list.size())

src/core/host.h

@@ -72,6 +72,9 @@ void ReportDebuggerMessage(std::string_view message);
 /// Returns a list of supported languages and codes (suffixes for translation files).
 std::span<const std::pair<const char*, const char*>> GetAvailableLanguageList();
 
+/// Returns the localized language name for the specified language code.
+const char* GetLanguageName(std::string_view language_code);
+
 /// Refreshes the UI when the language is changed.
 bool ChangeLanguage(const char* new_language);
 

src/duckstation-mini/mini_host.cpp

@@ -337,6 +337,11 @@ std::span<const std::pair<const char*, const char*>> Host::GetAvailableLanguageL
   return {};
 }
 
+const char* Host::GetLanguageName(std::string_view language_code)
+{
+  return "";
+}
+
 bool Host::ChangeLanguage(const char* new_language)
 {
   return false;

src/duckstation-qt/CMakeLists.txt

@@ -133,6 +133,7 @@ set(SRCS
   qtprogresscallback.cpp
   qtprogresscallback.h
   qtthemes.cpp
+  qttranslations.inl
   qtutils.cpp
   qtutils.h
   resource.h

src/duckstation-qt/interfacesettingswidget.cpp

@@ -49,8 +49,6 @@ const char* InterfaceSettingsWidget::THEME_VALUES[] = {
   nullptr,
 };
 
-const char* InterfaceSettingsWidget::DEFAULT_THEME_NAME = "darkfusion";
-
 InterfaceSettingsWidget::InterfaceSettingsWidget(SettingsWindow* dialog, QWidget* parent)
   : QWidget(parent), m_dialog(dialog)
 {
@@ -86,8 +84,7 @@ InterfaceSettingsWidget::InterfaceSettingsWidget(SettingsWindow* dialog, QWidget
     connect(m_ui.theme, QOverload<int>::of(&QComboBox::currentIndexChanged), [this]() { emit themeChanged(); });
 
     populateLanguageDropdown(m_ui.language);
-    SettingWidgetBinder::BindWidgetToStringSetting(sif, m_ui.language, "Main", "Language",
-                                                   QtHost::GetDefaultLanguage());
+    SettingWidgetBinder::BindWidgetToStringSetting(sif, m_ui.language, "Main", "Language", {});
     connect(m_ui.language, QOverload<int>::of(&QComboBox::currentIndexChanged), this,
             &InterfaceSettingsWidget::onLanguageChanged);
 
@@ -180,16 +177,8 @@ void InterfaceSettingsWidget::populateLanguageDropdown(QComboBox* cb)
 {
   for (const auto& [language, code] : Host::GetAvailableLanguageList())
   {
-    QString icon_filename(QStringLiteral(":/icons/flags/%1.png").arg(QLatin1StringView(code)));
-    if (!QFile::exists(icon_filename))
-    {
-      // try without the suffix (e.g. es-es -> es)
-      const char* pos = std::strrchr(code, '-');
-      if (pos)
-        icon_filename = QStringLiteral(":/icons/flags/%1.png").arg(QLatin1StringView(pos));
-    }
-
-    cb->addItem(QIcon(icon_filename), QString::fromUtf8(language), QString::fromLatin1(code));
+    cb->addItem(QtUtils::GetIconForTranslationLanguage(code), QString::fromUtf8(Host::GetLanguageName(code)),
+                QString::fromLatin1(code));
   }
 }
 

src/duckstation-qt/interfacesettingswidget.h

@@ -27,6 +27,8 @@ private Q_SLOTS:
   void onLanguageChanged();
 
 private:
+  void setupAdditionalUi();
+
   Ui::InterfaceSettingsWidget m_ui;
 
   SettingsWindow* m_dialog;
@@ -34,5 +36,4 @@ private:
 public:
   static const char* THEME_NAMES[];
   static const char* THEME_VALUES[];
-  static const char* DEFAULT_THEME_NAME;
 };

src/duckstation-qt/qthost.cpp

@@ -124,6 +124,7 @@ static void SaveSettings();
 static bool RunSetupWizard();
 static void UpdateFontOrder(std::string_view language);
 static void UpdateApplicationLocale(std::string_view language);
+static std::string_view GetSystemLanguage();
 static std::optional<bool> DownloadFile(QWidget* parent, const QString& title, std::string url, std::vector<u8>* data);
 static void InitializeEarlyConsole();
 static void HookSignals();
@@ -2263,9 +2264,11 @@ void QtHost::UpdateApplicationLanguage(QWidget* dialog_parent)
   }
   s_translators.clear();
 
-  // Fix old language names.
-  const std::string language = Host::GetBaseStringSettingValue("Main", "Language", GetDefaultLanguage());
-  const QString qlanguage = QString::fromStdString(language);
+  // Fixup automatic language.
+  std::string language = Host::GetBaseStringSettingValue("Main", "Language", "");
+  if (language.empty())
+    language = GetSystemLanguage();
+  QString qlanguage = QString::fromStdString(language);
 
   // install the base qt translation first
 #ifndef __APPLE__
@@ -2377,25 +2380,64 @@ SmallString Host::TranslatePluralToSmallString(const char* context, const char*
 
 std::span<const std::pair<const char*, const char*>> Host::GetAvailableLanguageList()
 {
-  static constexpr const std::pair<const char*, const char*> languages[] = {{"English", "en"},
-                                                                            {"Español de Latinoamérica", "es"},
-                                                                            {"Español de España", "es-ES"},
-                                                                            {"Français", "fr"},
-                                                                            {"Bahasa Indonesia", "id"},
-                                                                            {"日本語", "ja"},
-                                                                            {"한국어", "ko"},
-                                                                            {"Italiano", "it"},
-                                                                            {"Polski", "pl"},
-                                                                            {"Português (Pt)", "pt-PT"},
-                                                                            {"Português (Br)", "pt-BR"},
-                                                                            {"Русский", "ru"},
-                                                                            {"Svenska", "sv"},
-                                                                            {"Türkçe", "tr"},
-                                                                            {"简体中文", "zh-CN"}};
+  static constexpr const std::pair<const char*, const char*> languages[] = {
+    {QT_TRANSLATE_NOOP("QtHost", "System Language"), ""},
+
+#define TRANSLATION_LIST_ENTRY(name, our_translation_code, locale_code)                                                \
+  {name " [" our_translation_code "]", our_translation_code},
+#include "qttranslations.inl"
+#undef TRANSLATION_LIST_ENTRY
+  };
 
   return languages;
 }
 
+const char* Host::GetLanguageName(std::string_view language_code)
+{
+  for (const auto& [name, code] : GetAvailableLanguageList())
+  {
+    if (language_code == code)
+      return Host::TranslateToCString("QtHost", name);
+  }
+
+  return TRANSLATE("QtHost", "Unknown");
+}
+
+std::string_view QtHost::GetSystemLanguage()
+{
+  std::string locname = QLocale::system().name().toStdString();
+
+  // Does this match any of our translations?
+  for (const auto& [lname, lcode] : Host::GetAvailableLanguageList())
+  {
+    if (locname == lcode)
+      return lcode;
+  }
+
+  // Check for a partial match, e.g. "zh" for "zh-CN".
+  if (const std::string::size_type pos = locname.find('-'); pos != std::string::npos)
+  {
+    const std::string_view plocname = std::string_view(locname).substr(0, pos);
+    for (const auto& [lname, lcode] : Host::GetAvailableLanguageList())
+    {
+      // Only some languages have a country code, so we need to check both.
+      const std::string_view lcodev(lcode);
+      if (lcodev == plocname)
+      {
+        return lcode;
+      }
+      else if (const std::string_view::size_type lpos = lcodev.find('-'); lpos != std::string::npos)
+      {
+        if (lcodev.substr(0, lpos) == plocname)
+          return lcode;
+      }
+    }
+  }
+
+  // Fallback to English.
+  return "en";
+}
+
 bool Host::ChangeLanguage(const char* new_language)
 {
   Host::RunOnUIThread([new_language = std::string(new_language)]() {
@@ -2407,12 +2449,6 @@ bool Host::ChangeLanguage(const char* new_language)
   return true;
 }
 
-const char* QtHost::GetDefaultLanguage()
-{
-  // TODO: Default system language instead.
-  return "en";
-}
-
 void QtHost::UpdateFontOrder(std::string_view language)
 {
   // Why is this a thing? Because we want all glyphs to be available, but don't want to conflict

src/duckstation-qt/qthost.h

@@ -339,9 +339,6 @@ const QLocale& GetApplicationLocale();
 /// Default theme name for the platform.
 const char* GetDefaultThemeName();
 
-/// Default language for the platform.
-const char* GetDefaultLanguage();
-
 /// Sets application theme according to settings.
 void UpdateApplicationTheme();
 
@@ -366,9 +363,6 @@ bool CanRenderToMainWindow();
 /// Returns true if the separate-window display widget should use the main window coordinates.
 bool UseMainWindowGeometryForDisplayWindow();
 
-/// Default language for the platform.
-const char* GetDefaultLanguage();
-
 /// Call when the language changes.
 void UpdateApplicationLanguage(QWidget* dialog_parent);
 

src/duckstation-qt/qtthemes.cpp

@@ -1,7 +1,6 @@
 // SPDX-FileCopyrightText: 2019-2025 Connor McLaughlin <stenzek@gmail.com> and contributors.
 // SPDX-License-Identifier: CC-BY-NC-ND-4.0
 
-#include "interfacesettingswidget.h"
 #include "qthost.h"
 
 #include "util/imgui_fullscreen.h"
@@ -42,8 +41,7 @@ void QtHost::UpdateApplicationTheme()
 
 void QtHost::SetStyleFromSettings()
 {
-  const TinyString theme =
-    Host::GetBaseTinyStringSettingValue("UI", "Theme", InterfaceSettingsWidget::DEFAULT_THEME_NAME);
+  const TinyString theme = Host::GetBaseTinyStringSettingValue("UI", "Theme", QtHost::GetDefaultThemeName());
 
   if (theme == "qdarkstyle")
   {
@@ -398,8 +396,7 @@ void QtHost::SetIconThemeFromStyle()
 
 const char* Host::GetDefaultFullscreenUITheme()
 {
-  const TinyString theme =
-    Host::GetBaseTinyStringSettingValue("UI", "Theme", InterfaceSettingsWidget::DEFAULT_THEME_NAME);
+  const TinyString theme = Host::GetBaseTinyStringSettingValue("UI", "Theme", QtHost::GetDefaultThemeName());
 
   if (theme == "cobaltsky")
     return "CobaltSky";

src/duckstation-qt/qttranslations.inl

@@ -0,0 +1,20 @@
+// SPDX-FileCopyrightText: 2019-2025 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-License-Identifier: CC-BY-NC-ND-4.0
+
+// TRANSLATION_LIST_ENTRY(name, our_translation_code, locale_code)
+
+TRANSLATION_LIST_ENTRY("English", "en", "en-US")
+TRANSLATION_LIST_ENTRY("Español de Latinoamérica", "es", "es-ES")
+TRANSLATION_LIST_ENTRY("Español de España", "es-ES", "es-ES")
+TRANSLATION_LIST_ENTRY("Français", "fr", "fr-FR")
+TRANSLATION_LIST_ENTRY("Bahasa Indonesia", "id", "id-ID")
+TRANSLATION_LIST_ENTRY("日本語", "ja", "ja-JA")
+TRANSLATION_LIST_ENTRY("한국어", "ko", "ko-KO")
+TRANSLATION_LIST_ENTRY("Italiano", "it", "it-IT")
+TRANSLATION_LIST_ENTRY("Polski", "pl", "pl-PL")
+TRANSLATION_LIST_ENTRY("Português (Pt)", "pt-PT", "pt-PT")
+TRANSLATION_LIST_ENTRY("Português (Br)", "pt-BR", "pt-BR")
+TRANSLATION_LIST_ENTRY("Русский", "ru", "ru-RU")
+TRANSLATION_LIST_ENTRY("Svenska", "sv", "sv-SV")
+TRANSLATION_LIST_ENTRY("Türkçe", "tr", "tr-TR")
+TRANSLATION_LIST_ENTRY("简体中文", "zh-CN", "zh-CN")

src/duckstation-qt/qtutils.cpp

@@ -257,6 +257,31 @@ void QtUtils::ResizePotentiallyFixedSizeWindow(QWidget* widget, int width, int h
   widget->resize(width, height);
 }
 
+QIcon QtUtils::GetIconForTranslationLanguage(std::string_view language_name)
+{
+  QString icon_path;
+
+  if (!language_name.empty())
+  {
+    const QLatin1StringView qlanguage_name(language_name.data(), language_name.length());
+    icon_path = QStringLiteral(":/icons/flags/%1.png").arg(qlanguage_name);
+    if (!QFile::exists(icon_path))
+    {
+      // try without the suffix (e.g. es-es -> es)
+      const int index = qlanguage_name.indexOf('-');
+      if (index >= 0)
+        icon_path = QStringLiteral(":/icons/flags/%1.png").arg(qlanguage_name.left(index));
+    }
+  }
+  else
+  {
+    // no language specified, use the default icon
+    icon_path = QStringLiteral(":/icons/applications-system.png");
+  }
+
+  return QIcon(icon_path);
+}
+
 QIcon QtUtils::GetIconForRegion(ConsoleRegion region)
 {
   switch (region)

src/duckstation-qt/qtutils.h

@@ -103,6 +103,9 @@ void SetWindowResizeable(QWidget* widget, bool resizeable);
 /// Adjusts the fixed size for a window if it's not resizeable.
 void ResizePotentiallyFixedSizeWindow(QWidget* widget, int width, int height);
 
+/// Returns icon for language.
+QIcon GetIconForTranslationLanguage(std::string_view language_name);
+
 /// Returns icon for region.
 QIcon GetIconForRegion(ConsoleRegion region);
 QIcon GetIconForRegion(DiscRegion region);

src/duckstation-qt/setupwizarddialog.cpp

@@ -183,7 +183,7 @@ void SetupWizardDialog::setupUi()
   connect(m_ui.next, &QPushButton::clicked, this, &SetupWizardDialog::nextPage);
   connect(m_ui.cancel, &QPushButton::clicked, this, &SetupWizardDialog::confirmCancel);
 
-  setupLanguagePage();
+  setupLanguagePage(true);
   setupBIOSPage();
   setupGameListPage();
   setupControllerPage(true);
@@ -191,20 +191,27 @@ void SetupWizardDialog::setupUi()
   setupAchievementsPage(true);
 }
 
-void SetupWizardDialog::setupLanguagePage()
+void SetupWizardDialog::setupLanguagePage(bool initial)
 {
+  SettingWidgetBinder::DisconnectWidget(m_ui.theme);
+  m_ui.theme->clear();
   SettingWidgetBinder::BindWidgetToEnumSetting(nullptr, m_ui.theme, "UI", "Theme", InterfaceSettingsWidget::THEME_NAMES,
-                                               InterfaceSettingsWidget::THEME_VALUES,
-                                               InterfaceSettingsWidget::DEFAULT_THEME_NAME, "InterfaceSettingsWidget");
+                                               InterfaceSettingsWidget::THEME_VALUES, QtHost::GetDefaultThemeName(),
+                                               "MainWindow");
   connect(m_ui.theme, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &SetupWizardDialog::themeChanged);
 
+  SettingWidgetBinder::DisconnectWidget(m_ui.language);
+  m_ui.language->clear();
   InterfaceSettingsWidget::populateLanguageDropdown(m_ui.language);
-  SettingWidgetBinder::BindWidgetToStringSetting(nullptr, m_ui.language, "Main", "Language",
-                                                 QtHost::GetDefaultLanguage());
+  SettingWidgetBinder::BindWidgetToStringSetting(nullptr, m_ui.language, "Main", "Language", {});
   connect(m_ui.language, QOverload<int>::of(&QComboBox::currentIndexChanged), this,
           &SetupWizardDialog::languageChanged);
 
-  SettingWidgetBinder::BindWidgetToBoolSetting(nullptr, m_ui.autoUpdateEnabled, "AutoUpdater", "CheckAtStartup", true);
+  if (initial)
+  {
+    SettingWidgetBinder::BindWidgetToBoolSetting(nullptr, m_ui.autoUpdateEnabled, "AutoUpdater", "CheckAtStartup",
+                                                 true);
+  }
 }
 
 void SetupWizardDialog::themeChanged()
@@ -218,6 +225,7 @@ void SetupWizardDialog::languageChanged()
   // Skip the recreation, since we don't have many dynamic UI elements.
   QtHost::UpdateApplicationLanguage(this);
   m_ui.retranslateUi(this);
+  setupLanguagePage(false);
   setupControllerPage(false);
   setupGraphicsPage(false);
   setupAchievementsPage(false);
@@ -631,7 +639,8 @@ void SetupWizardDialog::setupAchievementsPage(bool initial)
 {
   if (initial)
   {
-    m_ui.achievementsIconLabel->setPixmap(QPixmap(QString::fromStdString(QtHost::GetResourcePath("images/ra-icon.webp", true))));
+    m_ui.achievementsIconLabel->setPixmap(
+      QPixmap(QString::fromStdString(QtHost::GetResourcePath("images/ra-icon.webp", true))));
     QFont title_font(m_ui.achievementsTitleLabel->font());
     title_font.setBold(true);
     title_font.setPixelSize(20);

src/duckstation-qt/setupwizarddialog.h

@@ -64,7 +64,7 @@ private:
   };
 
   void setupUi();
-  void setupLanguagePage();
+  void setupLanguagePage(bool initial);
   void setupBIOSPage();
   void setupGameListPage();
   void setupControllerPage(bool initial);

src/duckstation-regtest/regtest_host.cpp

@@ -191,6 +191,11 @@ std::span<const std::pair<const char*, const char*>> Host::GetAvailableLanguageL
   return {};
 }
 
+const char* Host::GetLanguageName(std::string_view language_code)
+{
+  return "";
+}
+
 bool Host::ChangeLanguage(const char* new_language)
 {
   return false;