[IME] Do not redraw and move caret on IME update w/o text/position changes.

Author: bruvzg

scene/gui/line_edit.cpp

@@ -1377,8 +1377,14 @@ void LineEdit::_notification(int p_what) {
 
 		case MainLoop::NOTIFICATION_OS_IME_UPDATE: {
 			if (editing) {
-				ime_text = DisplayServer::get_singleton()->ime_get_text();
-				ime_selection = DisplayServer::get_singleton()->ime_get_selection();
+				const String &new_ime_text = DisplayServer::get_singleton()->ime_get_text();
+				const Vector2i &new_ime_selection = DisplayServer::get_singleton()->ime_get_selection();
+				if (ime_text == new_ime_text && ime_selection == new_ime_selection) {
+					break;
+				}
+
+				ime_text = new_ime_text;
+				ime_selection = new_ime_selection;
 
 				if (!ime_text.is_empty()) {
 					selection_delete();

scene/gui/text_edit.cpp

@@ -1633,9 +1633,15 @@ void TextEdit::_notification(int p_what) {
 
 		case MainLoop::NOTIFICATION_OS_IME_UPDATE: {
 			if (has_focus()) {
+				const String &new_ime_text = DisplayServer::get_singleton()->ime_get_text();
+				const Vector2i &new_ime_selection = DisplayServer::get_singleton()->ime_get_selection();
+				if (ime_text == new_ime_text && ime_selection == new_ime_selection) {
+					break;
+				}
+
 				bool had_ime_text = has_ime_text();
-				ime_text = DisplayServer::get_singleton()->ime_get_text();
-				ime_selection = DisplayServer::get_singleton()->ime_get_selection();
+				ime_text = new_ime_text;
+				ime_selection = new_ime_selection;
 
 				if (!had_ime_text && has_ime_text()) {
 					_cancel_drag_and_drop_text();