Yaru tutorial step #3 (handy_window + my_application.cc) no longer produces rounded corners on Ubuntu

[alomia]

Description

In the TL;DR Yaru.dart crash course, steps #2 and #3 indicate that adding handy_window and modifying
linux/runner/my_application.cc should enable modern window behavior (e.g. rounded corners).

Using the current Flutter stable version:

Flutter 3.38.5 (stable)

Dart 3.10.4

Following the tutorial exactly as written produces no visual change:

Window corners remain square

Modifying my_application.cc has no visible effect

Additionally, the file linux/runner/my_application.cc has changed since the tutorial was published, so the instructions in step #3 no longer clearly apply.

This section of the tutorial appears to be outdated and may need to be updated or clarified for recent Flutter versions.

Thanks for maintaining the project.

[gamemode-3]

Hey, i ran into this as well, have you found out how to do it now?

[gamemode-3]

Found a way!

Here's my diff:

...

  if (use_header_bar)
  {
-   GtkHeaderBar* header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
-   gtk_widget_show(GTK_WIDGET(header_bar));
-   gtk_header_bar_set_title(header_bar, "test_app");
-   gtk_header_bar_set_show_close_button(header_bar, TRUE);
-   gtk_window_set_titlebar(window, GTK_WIDGET(header_bar));
  }
  else
  {
    gtk_window_set_title(window, "my_yaru_app");
  }

  gtk_window_set_default_size(window, 1280, 720);

  g_autoptr(FlDartProject) project = fl_dart_project_new();
  fl_dart_project_set_dart_entrypoint_arguments(
      project, self->dart_entrypoint_arguments);

  FlView *view = fl_view_new(project);
    
+ gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(view));

+ fl_register_plugins(FL_PLUGIN_REGISTRY(view));

  GdkRGBA background_color;
- // Background defaults to black, override it here if necessary, e.g. #00000000
- // for transparent.
- gdk_rgba_parse(&background_color, "#000000");
+ gdk_rgba_parse(&background_color, "#00000000");
  fl_view_set_background_color(view, &background_color);
  gtk_widget_show(GTK_WIDGET(view));
  gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(view));

  // Show the window when Flutter renders.
  // Requires the view to be realized so we can start rendering.
  g_signal_connect_swapped(view, "first-frame", G_CALLBACK(first_frame_cb),
                           self);
  gtk_widget_realize(GTK_WIDGET(view));

- fl_register_plugins(FL_PLUGIN_REGISTRY(view));

+ gtk_widget_show(GTK_WIDGET(view));

  gtk_widget_grab_focus(GTK_WIDGET(view));
}

...

The background_color change is from black to transparent, makes it not flash black.