feat(linux): use server-side window decorations by default

Author: Integral-Tech

linux/my_application.cc

@@ -20,24 +20,12 @@ static void my_application_activate(GApplication* application) {
   GtkWindow* window =
       GTK_WINDOW(gtk_application_window_new(GTK_APPLICATION(application)));
 
-  // Use a header bar when running in GNOME as this is the common style used
-  // by applications and is the setup most users will be using (e.g. Ubuntu
-  // desktop).
-  // If running on X and not using GNOME then just use a traditional title bar
-  // in case the window manager does more exotic layout, e.g. tiling.
-  // If running on Wayland assume the header bar will work (may need changing
-  // if future cases occur).
-  gboolean use_header_bar = TRUE;
-#ifdef GDK_WINDOWING_X11
-  GdkScreen* screen = gtk_window_get_screen(window);
-  if (GDK_IS_X11_SCREEN(screen)) {
-    const gchar* wm_name = gdk_x11_screen_get_window_manager_name(screen);
-    if (g_strcmp0(wm_name, "GNOME Shell") != 0) {
-      use_header_bar = FALSE;
-    }
-  }
-#endif
-  if (use_header_bar) {
+  // The following code is adapted from LocalSend
+  // (https://github.com/localsend/localsend/blob/main/app/linux/my_application.cc#L26-L37).
+  //
+  // Licensed under the Apache License, Version 2.0.
+  const char *GTK_CSD = getenv("GTK_CSD");
+  if (GTK_CSD && strcmp(GTK_CSD, "1") == 0) {
     GtkHeaderBar* header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
     gtk_widget_show(GTK_WIDGET(header_bar));
     gtk_header_bar_set_title(header_bar, "c001apk-flutter");