Support for loading language .qm files as Qt resource

CMakeLists.txt

@@ -71,10 +71,6 @@ find_package(
 
 set(CMAKE_AUTOUIC_SEARCH_PATHS ${QET_DIR}/sources/ui)
 
-qt_create_translation(QM_FILES ${CMAKE_SOURCE_DIR} ${TS_FILES})
-set_source_files_properties(${TS_FILES} PROPERTIES OUTPUT_LOCATION "${QET_DIR}/lang")
-qt_add_translation(QM_FILES ${TS_FILES})
-
 # als laatse
 include(cmake/define_definitions.cmake)
 
@@ -86,6 +82,14 @@ add_executable(
   ${QET_DIR}/qelectrotech.qrc
   )
 
+if(QMFILES_AS_RESOURCE)
+  qt_add_translations(${PROJECT_NAME} TS_FILES ${TS_FILES} RESOURCE_PREFIX "/lang")
+else()
+  qt_create_translation(QM_FILES ${CMAKE_SOURCE_DIR} ${TS_FILES})
+  set_source_files_properties(${TS_FILES} PROPERTIES OUTPUT_LOCATION "${QET_DIR}/lang")
+  qt_add_translation(QM_FILES ${TS_FILES})
+endif()
+
 find_package(SQLite3 REQUIRED)
 
 target_link_libraries(
@@ -152,6 +156,7 @@ install(FILES LICENSE ELEMENTS.LICENSE CREDIT README ChangeLog DESTINATION share
 install(FILES misc/org.qelectrotech.qelectrotech.desktop DESTINATION share/applications)
 install(FILES misc/qelectrotech.xml DESTINATION share/mime/packages)
 install(FILES misc/qelectrotech.appdata.xml DESTINATION ${QET_APPDATA_PATH})
-install(FILES ${QM_FILES} DESTINATION ${QET_LANG_PATH})
+if(NOT QMFILES_AS_RESOURCE)
-
+  install(FILES ${QM_FILES} DESTINATION ${QET_LANG_PATH})
+endif()
 endif()

cmake/define_definitions.cmake

@@ -69,3 +69,7 @@ else()
 endif()
 message("QET_COMPONENTS            :" ${QET_COMPONENTS})
 message("Qt version                :" ${Qt${QT_VERSION_MAJOR}_VERSION})
+
+if(QMFILES_AS_RESOURCE)
+  add_definitions(-DQMFILES_AS_RESOURCE)
+endif()

cmake/developer_options.cmake

@@ -33,3 +33,6 @@ add_definitions(-DQT_MESSAGELOGCONTEXT)
 
 # Build with KF6
 option(BUILD_WITH_KF6 "Build with KF6" ON)
+
+# Use translations as a Qt resource
+option(QMFILES_AS_RESOURCE "Use .qm files as Qt resource" ON)

sources/qetapp.cpp

@@ -222,6 +222,23 @@ void QETApp::setLanguage(const QString &desired_language) {
 
 	// load translations for the QET application
 	// charge les traductions pour l'application QET
+#ifdef QMFILES_AS_RESOURCE
+	if (!qetTranslator.load(QLocale(desired_language), "qet" "_", ":/lang")) {
+		/* in case of failure,
+		 *  we fall back on the native channels for French
+		 * en cas d'echec,
+		 *  on retombe sur les chaines natives pour le francais
+		 */
+		if (desired_language != "fr") {
+			// use of the English version by default
+			// utilisation de la version anglaise par defaut
+			if(!qetTranslator.load(QLocale(desired_language), "qet", "_", ":/lang"))
+				qWarning() << "failed to load"
+						   << ":/lang/qet_en.qm" << "(" << __FILE__
+						   << __LINE__ << __FUNCTION__ << ")";
+		}
+	}
+#else
 	if (!qetTranslator.load("qet_" + desired_language, languages_path)) {
 		/* in case of failure,
 		 *  we fall back on the native channels for French
@@ -237,6 +254,8 @@ void QETApp::setLanguage(const QString &desired_language) {
 						   << __LINE__ << __FUNCTION__ << ")";
 		}
 	}
+#endif
+	qInfo() << "Loaded language file:" << qetTranslator.filePath();
 	qApp->installTranslator(&qetTranslator);
 
 	QString ltr_special_string = tr(