qt: Use upstream Qt Base translations when available

src/citra_qt/CMakeLists.txt

@@ -218,7 +218,12 @@ if (ENABLE_QT_UPDATE_CHECKER)
 endif()
 
 if (ENABLE_QT_TRANSLATION)
-    set(CITRA_QT_LANGUAGES "${PROJECT_SOURCE_DIR}/dist/languages" CACHE PATH "Path to the translation bundle for the Qt frontend")
+    if (EXISTS "${QT_TARGET_PATH}/translations")
+        set(BASE_QT_LANGUAGES "${QT_TARGET_PATH}/translations" CACHE PATH "Path to Qt base translations")
+    else()
+        set(BASE_QT_LANGUAGES "${QT_TARGET_PATH}/share/qt6/translations" CACHE PATH "Path to Qt base translations")
+    endif()
+    set(CITRA_QT_LANGUAGES "${PROJECT_SOURCE_DIR}/dist/languages" CACHE PATH "Path to Citra translations")
     option(GENERATE_QT_TRANSLATION "Generate en.ts as the translation source file" OFF)
 
     # Update source TS file if enabled
@@ -235,17 +240,23 @@ if (ENABLE_QT_TRANSLATION)
         add_custom_target(translation ALL DEPENDS citra_qt_lupdate)
     endif()
 
-    # Find all TS files except en.ts
-    file(GLOB_RECURSE LANGUAGES_TS ${CITRA_QT_LANGUAGES}/*.ts)
-    list(REMOVE_ITEM LANGUAGES_TS ${CITRA_QT_LANGUAGES}/en.ts)
+    # Find all TS files for Citra translations except en.ts
+    file(GLOB_RECURSE CITRA_LANGUAGES_TS ${CITRA_QT_LANGUAGES}/*.ts)
+    list(REMOVE_ITEM CITRA_LANGUAGES_TS ${CITRA_QT_LANGUAGES}/en.ts)
 
-    # Compile TS files to QM files
-    qt_add_lrelease(citra_qt TS_FILES ${LANGUAGES_TS} NO_GLOBAL_TARGET QM_FILES_OUTPUT_VARIABLE LANGUAGES_QM)
+    # Compile Citra TS files to QM files
+    qt_add_lrelease(citra_qt TS_FILES ${CITRA_LANGUAGES_TS} NO_GLOBAL_TARGET QM_FILES_OUTPUT_VARIABLE CITRA_LANGUAGES_QM)
+
+    # Find all QM files for Qt translations
+    file(GLOB_RECURSE QT_LANGUAGES_QM ${BASE_QT_LANGUAGES}/qtbase_*.qm)
+
+    # Copy base QT QM files into build directory
+    file(COPY ${QT_LANGUAGES_QM} DESTINATION ${CMAKE_CURRENT_BINARY_DIR})
 
     # Build a QRC file from the QM file list
     set(LANGUAGES_QRC ${CMAKE_CURRENT_BINARY_DIR}/languages.qrc)
     file(WRITE ${LANGUAGES_QRC} "<RCC><qresource prefix=\"languages\">\n")
-    foreach (QM ${LANGUAGES_QM})
+    foreach (QM ${QT_LANGUAGES_QM} ${CITRA_LANGUAGES_QM})
         get_filename_component(QM_FILE ${QM} NAME)
         file(APPEND ${LANGUAGES_QRC} "<file>${QM_FILE}</file>\n")
     endforeach (QM)

src/citra_qt/citra_qt.cpp

@@ -7,6 +7,7 @@
 #include <memory>
 #include <optional>
 #include <thread>
+#include <unordered_map>
 #include <QFileDialog>
 #include <QFutureWatcher>
 #include <QIcon>
@@ -4097,7 +4098,7 @@ void GMainWindow::LoadTranslation() {
                 UISettings::values.language = lang_en;
                 return;
             }
-            loaded = translator.load(lang, languages_dir);
+            loaded = citraTranslator.load(lang, languages_dir);
             if (loaded) {
                 UISettings::values.language = lang;
                 break;
@@ -4110,16 +4111,22 @@ void GMainWindow::LoadTranslation() {
         return;
     }
 
+    const QString qtbase_prefix = QStringLiteral("qtbase_");
     if (UISettings::values.language.isEmpty() && !loaded) {
         // Use the system's default locale
-        loaded = translator.load(QLocale::system(), {}, {}, languages_dir);
+        qtTranslator.load(qtbase_prefix + QLocale::system().name(), {}, {},
+                          QStringLiteral(":/languages/"));
+        loaded = citraTranslator.load(QLocale::system(), {}, {}, QStringLiteral(":/languages/"));
     } else {
         // Otherwise load from the specified file
-        loaded = translator.load(UISettings::values.language, languages_dir);
+        qtTranslator.load(qtbase_prefix + UISettings::values.language,
+                          QStringLiteral(":/languages/"));
+        loaded = citraTranslator.load(UISettings::values.language, QStringLiteral(":/languages/"));
     }
 
     if (loaded) {
-        qApp->installTranslator(&translator);
+        qApp->installTranslator(&qtTranslator);
+        qApp->installTranslator(&citraTranslator);
     } else {
         UISettings::values.language = lang_en;
     }
@@ -4127,7 +4134,8 @@ void GMainWindow::LoadTranslation() {
 
 void GMainWindow::OnLanguageChanged(const QString& locale) {
     if (UISettings::values.language != QStringLiteral("en")) {
-        qApp->removeTranslator(&translator);
+        qApp->removeTranslator(&qtTranslator);
+        qApp->removeTranslator(&citraTranslator);
     }
 
     UISettings::values.language = locale;

src/citra_qt/citra_qt.h

@@ -439,7 +439,8 @@ private:
     QAction* action_secondary_swap_screen;
     QAction* action_secondary_rotate_screen;
 
-    QTranslator translator;
+    QTranslator qtTranslator;
+    QTranslator citraTranslator;
 
     // stores default icon theme search paths for the platform
     QStringList default_theme_paths;

src/citra_qt/configuration/configure_ui.cpp

@@ -24,12 +24,17 @@ ConfigureUi::~ConfigureUi() = default;
 
 void ConfigureUi::InitializeLanguageComboBox() {
     ui->language_combobox->addItem(tr("<System>"), QString{});
-    ui->language_combobox->addItem(tr("English"), QStringLiteral("en"));
+    ui->language_combobox->addItem(QStringLiteral("English"), QStringLiteral("en"));
     QDirIterator it(QStringLiteral(":/languages"), QDirIterator::NoIteratorFlags);
     while (it.hasNext()) {
         QString locale = it.next();
         locale.truncate(locale.lastIndexOf(QLatin1Char{'.'}));
         locale.remove(0, locale.lastIndexOf(QLatin1Char{'/'}) + 1);
+        if (locale.startsWith(QStringLiteral("qtbase"))) {
+            // The Qt Base QM translation files are lumped in with ours,
+            // so don't show them in the language list!
+            continue;
+        }
         QString lang = QLocale::languageToString(QLocale(locale).language());
         const QString country = QLocale::territoryToString(QLocale(locale).territory());
         if (locale == QString::fromStdString("ca_ES_valencia")) {