Gui: add preference to use selected language number formatting, fixes #6330

If not enabled (default), will defaults to C/POSIX formatting

src/Gui/Application.cpp

@@ -1920,13 +1920,11 @@ void Application::runApplication(void)
     // http://forum.freecadweb.org/viewtopic.php?f=3&t=15540
     mainApp.setAttribute(Qt::AA_DontShowIconsInMenus, false);
 
-#ifdef Q_OS_UNIX
     // Make sure that we use '.' as decimal point. See also
     // http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=559846
     // and issue #0002891
     // http://doc.qt.io/qt-5/qcoreapplication.html#locale-settings
     setlocale(LC_NUMERIC, "C");
-#endif
 
     // check if a single or multiple instances can run
     it = cfg.find("SingleInstance");
@@ -2072,6 +2070,13 @@ void Application::runApplication(void)
         mainApp.installEventFilter(filter);
     }
 
+    if (hGrp->GetBool("UseLocaleFormatting", false)) {
+        Translator::instance()->setLocale(hGrp->GetASCII(("Language"), Translator::instance()->activeLanguage().c_str()));
+    }
+    else {
+        Translator::instance()->setLocale("C");
+    }
+
     // set text cursor blinking state
     int blinkTime = hGrp->GetBool("EnableCursorBlinking", true) ? -1 : 0;
     qApp->setCursorFlashTime(blinkTime);

src/Gui/DlgGeneral.ui

@@ -89,7 +89,7 @@
            </item>
           </layout>
          </item>
-         <item row="1" column="0">
+         <item row="1" column="1">
           <widget class="Gui::PrefCheckBox" name="SubstituteDecimal">
            <property name="toolTip">
             <string>If enabled, numerical keypad decimal separator will be substituted with locale separator</string>
@@ -105,6 +105,23 @@
            </property>
           </widget>
          </item>
+         <item row="1" column="0">
+          <widget class="Gui::PrefCheckBox" name="UseLocaleFormatting">
+           <property name="toolTip">
+            <string>If enabled, number formatting will be set according to selected language
+If not, C/POSIX default formatting will be used (English-like)</string>
+           </property>
+           <property name="text">
+            <string>Use selected language number format</string>
+           </property>
+           <property name="prefEntry" stdset="0">
+            <cstring>UseLocaleFormatting</cstring>
+           </property>
+           <property name="prefPath" stdset="0">
+            <cstring>General</cstring>
+           </property>
+          </widget>
+         </item>
         </layout>
        </widget>
       </item>

src/Gui/DlgGeneralImp.cpp

@@ -128,6 +128,7 @@ void DlgGeneralImp::saveSettings()
                           SetASCII("AutoloadModule", startWbName.toLatin1());
 
     ui->SubstituteDecimal->onSave();
+    ui->UseLocaleFormatting->onSave();
     ui->RecentFiles->onSave();
     ui->EnableCursorBlinking->onSave();
     ui->SplashScreen->onSave();
@@ -141,6 +142,8 @@ void DlgGeneralImp::saveSettings()
         hGrp->SetASCII("Language", current.constData());
         Translator::instance()->activateLanguage(current.constData());
     }
+    if (ui->UseLocaleFormatting->isChecked())
+        Translator::instance()->setLocale(current.constData());
 
     QVariant size = ui->toolbarIconSize->itemData(ui->toolbarIconSize->currentIndex());
     int pixel = size.toInt();
@@ -183,14 +186,15 @@ void DlgGeneralImp::loadSettings()
     ui->AutoloadModuleCombo->setCurrentIndex(ui->AutoloadModuleCombo->findData(startWbName));
 
     ui->SubstituteDecimal->onRestore();
+    ui->UseLocaleFormatting->onRestore();
     ui->RecentFiles->onRestore();
     ui->EnableCursorBlinking->onRestore();
     ui->SplashScreen->onRestore();
 
     // search for the language files
     ParameterGrp::handle hGrp = WindowParameter::getDefaultParameter()->GetGroup("General");
-    QString langToStr = QLocale::languageToString(QLocale().language());
-    QByteArray language = hGrp->GetASCII("Language", langToStr.toLatin1()).c_str();
+    auto langToStr = Translator::instance()->activeLanguage();
+    QByteArray language = hGrp->GetASCII("Language", langToStr.c_str()).c_str();
 
     int index = 1;
     TStringMap list = Translator::instance()->supportedLocales();

src/Gui/Language/Translator.cpp

@@ -251,6 +251,19 @@ std::string Translator::locale(const std::string& lang) const
     return loc;
 }
 
+bool Translator::setLocale(const std::string& language) const
+{
+    auto loc = QLocale::c(); //Defaulting to POSIX locale
+    auto bcp47 = locale(language);
+    if (!bcp47.empty())
+        loc  = QLocale(QString::fromStdString(bcp47));
+    QLocale::setDefault(loc);
+#ifdef FC_DEBUG
+    Base::Console().Log("Locale changed to %s => %s\n", qPrintable(loc.bcp47Name()), qPrintable(loc.name()));
+#endif
+    return (loc.language() != loc.C);
+}
+
 QStringList Translator::directories() const
 {
     QStringList list; 

src/Gui/Language/Translator.h

@@ -66,6 +66,8 @@ public:
     std::string activeLanguage() const;
     /** Returns the locale (e.g. "de") to the given language name. */
     std::string locale(const std::string&) const;
+    /** Sets default Qt locale based on given language name. Returns true if matching QLocale found**/
+    bool setLocale(const std::string&) const;
     /** Returns a list of supported languages. */
     TStringList supportedLanguages() const;
     /** Returns a map of supported languages/locales. */