Find and add supported languages in settings GUI

src/control/Control.cpp

@@ -2460,7 +2460,13 @@ void Control::closeDocument() {
     this->undoRedoChanged();
 }
 
-void Control::applyPreferredLanguage() { setenv("LANGUAGE", this->settings->getPreferredLocale().c_str(), 1); }
+void Control::applyPreferredLanguage() {
+#ifdef _WIN32
+    _putenv_s("LANGUAGE", this->settings->getPreferredLocale().c_str());
+#else
+    setenv("LANGUAGE", this->settings->getPreferredLocale().c_str(), 1);
+#endif
+}
 
 auto Control::askToReplace(fs::path const& filepath) const -> bool {
     if (fs::exists(filepath)) {

src/gui/dialog/LanguageConfigGui.cpp

@@ -1,27 +1,89 @@
 #include "LanguageConfigGui.h"
-#include "i18n.h"
+
+#include <algorithm>
+
 #include "control/settings/Settings.h"
 
-LanguageConfigGui::LanguageConfigGui(GladeSearchpath* gladeSearchPath, GtkWidget* w, Settings* settings) :
+#include "StringUtils.h"
+#include "XojMsgBox.h"
+#include "config-paths.h"
+#include "config.h"
+#include "filesystem.h"
+#include "i18n.h"
+
+#ifdef _WIN32
+#undef PACKAGE_LOCALE_DIR
+#define PACKAGE_LOCALE_DIR "../share/locale/"
+#endif
+
+#ifdef __APPLE__
+#include "Stacktrace.h"
+#undef PACKAGE_LOCALE_DIR
+const char* PACKAGE_LOCALE_DIR = (Stacktrace::getExePath() / "../Resources/share/locale").c_str();
+#endif
+
+LanguageConfigGui::LanguageConfigGui(GladeSearchpath* gladeSearchPath, GtkWidget* w, Settings* settings):
         GladeGui(gladeSearchPath, "settingsLanguageConfig.glade", "offscreenwindow"), settings(settings) {
-    GtkWidget* dropdown = get("languageSettingsDropdown");
+    auto dropdown = get("languageSettingsDropdown");
     gtk_container_remove(GTK_CONTAINER(getWindow()), dropdown);
     gtk_container_add(GTK_CONTAINER(w), dropdown);
     gtk_widget_show_all(dropdown);
-};
+
+    // Fetch available locales
+    try {
+        fs::path baseLocaleDir(PACKAGE_LOCALE_DIR);
+        for (auto const& d: fs::directory_iterator(baseLocaleDir)) {
+            if (fs::exists(d.path() / "LC_MESSAGES" / (std::string(GETTEXT_PACKAGE) + ".mo"))) {
+                availableLocales.push_back(d.path().filename().u8string());
+            }
+        }
+    } catch (fs::filesystem_error const& e) {
+        g_warning("%s", e.what());
+    }
+    std::sort(availableLocales.begin(), availableLocales.end());
+
+    // No pot file for English
+    if (auto enPos = std::lower_bound(availableLocales.begin(), availableLocales.end(), "en");
+        enPos != availableLocales.end() && !StringUtils::startsWith(*enPos, "en")) {
+        availableLocales.insert(enPos, "en");
+    }
+
+    // Default
+    availableLocales.insert(availableLocales.begin(), _("System Default"));
+
+    auto gtkAvailableLocales = gtk_list_store_new(1, G_TYPE_STRING);
+    for (auto const& i: availableLocales) {
+        GtkTreeIter iter;
+        gtk_list_store_append(gtkAvailableLocales, &iter);
+        gtk_list_store_set(gtkAvailableLocales, &iter, 0, i.c_str(), -1);
+    }
+    gtk_combo_box_set_model(GTK_COMBO_BOX(dropdown), GTK_TREE_MODEL(gtkAvailableLocales));
+
+
+    // Set the current locale if previously selected
+    auto prefPos = availableLocales.begin();
+    if (auto preferred = settings->getPreferredLocale(); !preferred.empty()) {
+        prefPos = std::lower_bound(availableLocales.begin(), availableLocales.end(), preferred);
+        if (*prefPos != preferred) {
+            XojMsgBox::showErrorToUser(nullptr, _("Previously selected language not available anymore!"));
+
+            // Use system default
+            prefPos = availableLocales.begin();
+        }
+    }
+    gtk_combo_box_set_active(GTK_COMBO_BOX(dropdown), prefPos - availableLocales.begin());
+}
+
 
 void LanguageConfigGui::saveSettings() {
     gint pos = gtk_combo_box_get_active(GTK_COMBO_BOX(get("languageSettingsDropdown")));
+    auto pref = (pos == 0) ? "" : availableLocales[pos];
 
-    switch (pos) {
-        case 0:
-            settings->setPreferredLocale("en_US.UTF-8");
-            break;
-        case 1:
-            settings->setPreferredLocale("de_DE.UTF-8");
-            break;
-        default:
-            throw "No language selected";
-    }
+    settings->setPreferredLocale(pref);
     settings->customSettingsChanged();
+#ifdef _WIN32
+    _putenv_s("LANGUAGE", this->settings->getPreferredLocale().c_str());
+#else
+    setenv("LANGUAGE", this->settings->getPreferredLocale().c_str(), 1);
+#endif
 }

src/gui/dialog/LanguageConfigGui.h

@@ -11,8 +11,11 @@
 
 #pragma once
 
-#include <gdk/gdk.h>
 #include <memory>
+#include <vector>
+
+#include <gdk/gdk.h>
+
 #include "gui/GladeGui.h"
 
 class Settings;
@@ -23,14 +26,15 @@ public:
     LanguageConfigGui(GladeSearchpath* gladeSearchPath, GtkWidget* w, Settings* settings);
 
 public:
-    void loadSettings() {};
+    void loadSettings(){};
     void saveSettings();
 
     // Not implemented! This is not a dialog!
-    void show(GtkWindow* parent) override {};
+    void show(GtkWindow* parent) override{};
 
 private:
+    std::vector<std::string> availableLocales;
+
 
-private:
     Settings* settings;
 };

src/gui/dialog/SettingsDialog.h

@@ -17,11 +17,10 @@
 #include "util/audio/DeviceInfo.h"
 
 #include "DeviceClassConfigGui.h"
-#include "LatexSettingsPanel.h"
 #include "LanguageConfigGui.h"
+#include "LatexSettingsPanel.h"
 
 class ButtonConfigGui;
-class LanguageConfigGui;
 
 class SettingsDialog: public GladeGui {
 public: