Add translation preview in editor

core/string/translation_domain.cpp

@@ -284,7 +284,7 @@ void TranslationDomain::clear() {
 }
 
 StringName TranslationDomain::translate(const StringName &p_message, const StringName &p_context) const {
-	const String &locale = TranslationServer::get_singleton()->get_locale();
+	const String &locale = locale_override.is_empty() ? TranslationServer::get_singleton()->get_locale() : locale_override;
 	StringName res = get_message_from_translations(locale, p_message, p_context);
 
 	const String &fallback = TranslationServer::get_singleton()->get_fallback_locale();
@@ -299,7 +299,7 @@ StringName TranslationDomain::translate(const StringName &p_message, const Strin
 }
 
 StringName TranslationDomain::translate_plural(const StringName &p_message, const StringName &p_message_plural, int p_n, const StringName &p_context) const {
-	const String &locale = TranslationServer::get_singleton()->get_locale();
+	const String &locale = locale_override.is_empty() ? TranslationServer::get_singleton()->get_locale() : locale_override;
 	StringName res = get_message_from_translations(locale, p_message, p_message_plural, p_n, p_context);
 
 	const String &fallback = TranslationServer::get_singleton()->get_fallback_locale();
@@ -316,6 +316,15 @@ StringName TranslationDomain::translate_plural(const StringName &p_message, cons
 	return res;
 }
 
+String TranslationDomain::get_locale_override() const {
+	return locale_override;
+}
+
+void TranslationDomain::set_locale_override(const String &p_locale) {
+	String new_locale = p_locale.is_empty() ? p_locale : TranslationServer::get_singleton()->standardize_locale(p_locale);
+	locale_override = new_locale;
+}
+
 bool TranslationDomain::is_pseudolocalization_enabled() const {
 	return pseudolocalization.enabled;
 }
@@ -417,6 +426,8 @@ void TranslationDomain::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("clear"), &TranslationDomain::clear);
 	ClassDB::bind_method(D_METHOD("translate", "message", "context"), &TranslationDomain::translate, DEFVAL(StringName()));
 	ClassDB::bind_method(D_METHOD("translate_plural", "message", "message_plural", "n", "context"), &TranslationDomain::translate_plural, DEFVAL(StringName()));
+	ClassDB::bind_method(D_METHOD("get_locale_override"), &TranslationDomain::get_locale_override);
+	ClassDB::bind_method(D_METHOD("set_locale_override", "locale"), &TranslationDomain::set_locale_override);
 
 	ClassDB::bind_method(D_METHOD("is_pseudolocalization_enabled"), &TranslationDomain::is_pseudolocalization_enabled);
 	ClassDB::bind_method(D_METHOD("set_pseudolocalization_enabled", "enabled"), &TranslationDomain::set_pseudolocalization_enabled);

core/string/translation_domain.h

@@ -50,6 +50,7 @@ class TranslationDomain : public RefCounted {
 		String suffix = "]";
 	};
 
+	String locale_override;
 	HashSet<Ref<Translation>> translations;
 	PseudolocalizationConfig pseudolocalization;
 
@@ -80,6 +81,9 @@ class TranslationDomain : public RefCounted {
 	StringName translate(const StringName &p_message, const StringName &p_context) const;
 	StringName translate_plural(const StringName &p_message, const StringName &p_message_plural, int p_n, const StringName &p_context) const;
 
+	String get_locale_override() const;
+	void set_locale_override(const String &p_locale);
+
 	bool is_pseudolocalization_enabled() const;
 	void set_pseudolocalization_enabled(bool p_enabled);
 	bool is_pseudolocalization_accents_enabled() const;

core/string/translation_server.h

@@ -74,6 +74,7 @@ class TranslationServer : public Object {
 public:
 	_FORCE_INLINE_ static TranslationServer *get_singleton() { return singleton; }
 
+	Ref<TranslationDomain> get_main_domain() const { return main_domain; }
 	Ref<TranslationDomain> get_editor_domain() const { return editor_domain; }
 
 	void set_enabled(bool p_enabled) { enabled = p_enabled; }

doc/classes/TranslationDomain.xml

@@ -6,6 +6,7 @@
 	<description>
 		[TranslationDomain] is a self-contained collection of [Translation] resources. Translations can be added to or removed from it.
 		If you're working with the main translation domain, it is more convenient to use the wrap methods on [TranslationServer].
+		Because translation domain is intended to be advanced usage, modifications to it do not emit [constant MainLoop.NOTIFICATION_TRANSLATION_CHANGED] on the scene tree automatically. See the description of methods and properties below for details.
 	</description>
 	<tutorials>
 	</tutorials>
@@ -23,6 +24,12 @@
 				Removes all translations.
 			</description>
 		</method>
+		<method name="get_locale_override" qualifiers="const">
+			<return type="String" />
+			<description>
+				Returns the locale override of the domain. Returns an empty string if locale override is disabled.
+			</description>
+		</method>
 		<method name="get_translation_object" qualifiers="const">
 			<return type="Translation" />
 			<param index="0" name="locale" type="String" />
@@ -44,6 +51,15 @@
 				Removes the given translation.
 			</description>
 		</method>
+		<method name="set_locale_override">
+			<return type="void" />
+			<param index="0" name="locale" type="String" />
+			<description>
+				Sets the locale override of the domain.
+				If [param locale] is an empty string, locale override is disabled. Otherwise, [param locale] will be standardized to match known locales (e.g. [code]en-US[/code] would be matched to [code]en_US[/code]).
+				[b]Note: [/b] Updating this property does not automatically update texts in the scene tree. Please propagate the [constant MainLoop.NOTIFICATION_TRANSLATION_CHANGED] signal manually.
+			</description>
+		</method>
 		<method name="translate" qualifiers="const">
 			<return type="StringName" />
 			<param index="0" name="message" type="StringName" />

editor/editor_node.cpp

@@ -466,6 +466,10 @@ void EditorNode::_update_from_settings() {
 
 	ResourceImporterTexture::get_singleton()->update_imports();
 
+	TranslationServer::get_singleton()->clear();
+	TranslationServer::get_singleton()->load_translations();
+	scene_root->propagate_notification(NOTIFICATION_TRANSLATION_CHANGED);
+
 #ifdef DEBUG_ENABLED
 	NavigationServer3D::get_singleton()->set_debug_navigation_edge_connection_color(GLOBAL_GET("debug/shapes/navigation/edge_connection_color"));
 	NavigationServer3D::get_singleton()->set_debug_navigation_geometry_edge_color(GLOBAL_GET("debug/shapes/navigation/geometry_edge_color"));
@@ -3673,6 +3677,21 @@ void EditorNode::set_edited_scene_root(Node *p_scene, bool p_auto_add) {
 	}
 }
 
+String EditorNode::get_preview_locale() const {
+	const String override = TranslationServer::get_singleton()->get_main_domain()->get_locale_override();
+	// Override should always be non-empty, but just in case.
+	return override.is_empty() ? TranslationServer::get_singleton()->get_locale() : override;
+}
+
+void EditorNode::set_preview_locale(const String &p_locale) {
+	Ref<TranslationDomain> main_domain = TranslationServer::get_singleton()->get_main_domain();
+	if (main_domain->get_locale_override() == p_locale) {
+		return;
+	}
+	TranslationServer::get_singleton()->get_main_domain()->set_locale_override(p_locale);
+	scene_root->propagate_notification(NOTIFICATION_TRANSLATION_CHANGED);
+}
+
 Dictionary EditorNode::_get_main_scene_state() {
 	Dictionary state;
 	state["scene_tree_offset"] = SceneTreeDock::get_singleton()->get_tree_editor()->get_scene_tree()->get_vscroll_bar()->get_value();
@@ -6459,6 +6478,9 @@ void EditorNode::_bind_methods() {
 
 	ClassDB::bind_method("set_edited_scene", &EditorNode::set_edited_scene);
 
+	ClassDB::bind_method("get_preview_locale", &EditorNode::get_preview_locale);
+	ClassDB::bind_method(D_METHOD("set_preview_locale", "locale"), &EditorNode::set_preview_locale);
+
 	ClassDB::bind_method("stop_child_process", &EditorNode::stop_child_process);
 
 	ADD_SIGNAL(MethodInfo("request_help_search"));
@@ -6996,6 +7018,7 @@ EditorNode::EditorNode() {
 	editor_main_screen->set_v_size_flags(Control::SIZE_EXPAND_FILL);
 
 	scene_root = memnew(SubViewport);
+	scene_root->set_translation_domain(StringName());
 	scene_root->set_embedding_subwindows(true);
 	scene_root->set_disable_3d(true);
 	scene_root->set_disable_input(true);

editor/editor_node.h

@@ -769,6 +769,9 @@ class EditorNode : public Node {
 	void set_edited_scene_root(Node *p_scene, bool p_auto_add);
 	Node *get_edited_scene() { return editor_data.get_edited_scene_root(); }
 
+	String get_preview_locale() const;
+	void set_preview_locale(const String &p_locale);
+
 	void fix_dependencies(const String &p_for_file);
 	int new_scene();
 	Error load_scene(const String &p_scene, bool p_ignore_broken_deps = false, bool p_set_inherited = false, bool p_clear_errors = true, bool p_force_open_imported = false, bool p_silent_change_tab = false);

editor/editor_settings.cpp

@@ -1212,6 +1212,9 @@ void EditorSettings::setup_language() {
 	String lang = get("interface/editor/editor_language");
 	TranslationServer::get_singleton()->set_locale(lang);
 
+	// Used by edited scene.
+	TranslationServer::get_singleton()->get_main_domain()->set_locale_override("en");
+
 	if (lang == "en") {
 		return; // Default, nothing to do.
 	}

editor/plugins/canvas_item_editor_plugin.cpp

@@ -33,6 +33,7 @@
 #include "core/config/project_settings.h"
 #include "core/input/input.h"
 #include "core/os/keyboard.h"
+#include "core/string/translation_server.h"
 #include "editor/debugger/editor_debugger_node.h"
 #include "editor/editor_main_screen.h"
 #include "editor/editor_node.h"
@@ -63,6 +64,7 @@
 #include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 #include "scene/resources/style_box_texture.h"
+#include "scene/scene_string_names.h"
 
 #define RULER_WIDTH (15 * EDSCALE)
 #define DRAG_THRESHOLD (8 * EDSCALE)
@@ -1062,6 +1064,36 @@ void CanvasItemEditor::_switch_theme_preview(int p_mode) {
 	EditorNode::get_singleton()->update_preview_themes(theme_preview);
 }
 
+void CanvasItemEditor::_prepare_translation_menu() {
+	translation_menu->clear();
+	translation_menu->add_radio_check_item(TTR("None"));
+	translation_menu->set_item_metadata(-1, "en");
+
+	Vector<String> locales = TranslationServer::get_singleton()->get_loaded_locales();
+
+	const String current_preview_locale = EditorNode::get_singleton()->get_preview_locale();
+	if (!locales.is_empty()) {
+		translation_menu->add_separator();
+	}
+	bool using_default = true;
+	for (const String &locale : locales) {
+		translation_menu->add_radio_check_item(locale);
+		translation_menu->set_item_metadata(-1, locale);
+		if (locale == current_preview_locale) {
+			translation_menu->set_item_checked(-1, true);
+			using_default = false;
+		}
+	}
+	if (using_default) {
+		translation_menu->set_item_checked(0, true);
+	}
+}
+
+void CanvasItemEditor::_switch_translation_preview(int p_translation) {
+	view_menu->get_popup()->hide();
+	EditorNode::get_singleton()->set_preview_locale(translation_menu->get_item_metadata(p_translation));
+}
+
 bool CanvasItemEditor::_gui_input_rulers_and_guides(const Ref<InputEvent> &p_event) {
 	EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
 	Ref<InputEventMouseButton> b = p_event;
@@ -5582,6 +5614,12 @@ CanvasItemEditor::CanvasItemEditor() {
 		theme_menu->set_item_checked(i, i == theme_preview);
 	}
 
+	translation_menu = memnew(PopupMenu);
+	translation_menu->set_auto_translate_mode(AUTO_TRANSLATE_MODE_DISABLED);
+	translation_menu->connect("about_to_popup", callable_mp(this, &CanvasItemEditor::_prepare_translation_menu));
+	translation_menu->connect("index_pressed", callable_mp(this, &CanvasItemEditor::_switch_translation_preview));
+	p->add_submenu_node_item(TTR("Preview Translation"), translation_menu);
+
 	main_menu_hbox->add_child(memnew(VSeparator));
 
 	// Contextual toolbars.

editor/plugins/canvas_item_editor_plugin.h

@@ -339,6 +339,7 @@ class CanvasItemEditor : public VBoxContainer {
 	MenuButton *view_menu = nullptr;
 	PopupMenu *grid_menu = nullptr;
 	PopupMenu *theme_menu = nullptr;
+	PopupMenu *translation_menu = nullptr;
 	PopupMenu *gizmos_menu = nullptr;
 	HBoxContainer *animation_hb = nullptr;
 	MenuButton *animation_menu = nullptr;
@@ -432,6 +433,9 @@ class CanvasItemEditor : public VBoxContainer {
 	ThemePreviewMode theme_preview = THEME_PREVIEW_PROJECT;
 	void _switch_theme_preview(int p_mode);
 
+	void _prepare_translation_menu();
+	void _switch_translation_preview(int p_translation);
+
 	List<CanvasItem *> _get_edited_canvas_items(bool p_retrieve_locked = false, bool p_remove_canvas_item_if_parent_in_selection = true, bool *r_has_locked_items = nullptr) const;
 	Rect2 _get_encompassing_rect_from_list(const List<CanvasItem *> &p_list);
 	void _expand_encompassing_rect_using_children(Rect2 &r_rect, const Node *p_node, bool &r_first, const Transform2D &p_parent_xform = Transform2D(), const Transform2D &p_canvas_xform = Transform2D(), bool include_locked_nodes = true);

scene/main/node.cpp

@@ -113,13 +113,6 @@ void Node::_notification(int p_notification) {
 			data.is_auto_translate_dirty = true;
 			data.is_translation_domain_dirty = true;
 
-#ifdef TOOLS_ENABLED
-			// Don't translate UI elements when they're being edited.
-			if (is_part_of_edited_scene()) {
-				set_message_translation(false);
-			}
-#endif
-
 			if (data.auto_translate_mode != AUTO_TRANSLATE_MODE_DISABLED) {
 				notification(NOTIFICATION_TRANSLATION_CHANGED);
 			}