Delay the window until the first frame is received from the Flutter engine

shell/platform/linux/fl_application.cc

@@ -14,27 +14,15 @@
 #include "flutter/shell/platform/linux/public/flutter_linux/fl_view.h"
 
 struct FlApplicationPrivate {
-  // Default window title to use.
-  gchar* window_title;
-
   // Arguments to pass to Dart.
   gchar** dart_entrypoint_arguments;
-
-  // Default width of a Flutter window in pixels.
-  int window_width;
-
-  // Default height of a Flutter window in pixels.
-  int window_height;
-
-  // The main window.
-  GtkApplicationWindow* window;
 };
 
 #define FL_APPLICATION_GET_PRIVATE(app)                        \
   ((FlApplicationPrivate*)fl_application_get_instance_private( \
       FL_APPLICATION(app)))
 
-enum { kSignalRegisterPlugins, kSignalLastSignal };
+enum { kSignalRegisterPlugins, kSignalCreateWindow, kSignalLastSignal };
 
 static guint fl_application_signals[kSignalLastSignal];
 
@@ -44,23 +32,23 @@ G_DEFINE_TYPE_WITH_CODE(FlApplication,
                         G_ADD_PRIVATE(FlApplication))
 
 // Called when the first frame is received.
-static void first_frame_cb(FlApplication* self) {
-  FlApplicationPrivate* priv = FL_APPLICATION_GET_PRIVATE(self);
+static void first_frame_cb(FlApplication* self, FlView* view) {
+  GtkWidget* window = gtk_widget_get_toplevel(GTK_WIDGET(view));
 
   // Show the main window.
-  gtk_window_present(GTK_WINDOW(priv->window));
+  if (window != nullptr && GTK_IS_WINDOW(window)) {
+    gtk_window_present(GTK_WINDOW(window));
+  }
 }
 
 // Default implementation of FlApplication::register_plugins
 static void fl_application_register_plugins(FlApplication* self,
                                             FlPluginRegistry* registry) {}
 
-// Implements GApplication::activate.
-static void fl_application_activate(GApplication* application) {
-  FlApplication* self = FL_APPLICATION(application);
-  FlApplicationPrivate* priv = FL_APPLICATION_GET_PRIVATE(self);
-
-  priv->window =
+// Default implementation of FlApplication::create_window
+static GtkWindow* fl_application_create_window(FlApplication* self,
+                                               FlView* view) {
+  GtkApplicationWindow* window =
       GTK_APPLICATION_WINDOW(gtk_application_window_new(GTK_APPLICATION(self)));
 
   // Use a header bar when running in GNOME as this is the common style used
@@ -72,7 +60,7 @@ static void fl_application_activate(GApplication* application) {
   // if future cases occur).
   gboolean use_header_bar = TRUE;
 #ifdef GDK_WINDOWING_X11
-  GdkScreen* screen = gtk_window_get_screen(GTK_WINDOW(priv->window));
+  GdkScreen* screen = gtk_window_get_screen(GTK_WINDOW(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) {
@@ -83,15 +71,19 @@ static void fl_application_activate(GApplication* application) {
   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, priv->window_title);
     gtk_header_bar_set_show_close_button(header_bar, TRUE);
-    gtk_window_set_titlebar(GTK_WINDOW(priv->window), GTK_WIDGET(header_bar));
-  } else {
-    gtk_window_set_title(GTK_WINDOW(priv->window), priv->window_title);
+    gtk_window_set_titlebar(GTK_WINDOW(window), GTK_WIDGET(header_bar));
   }
 
-  gtk_window_set_default_size(GTK_WINDOW(priv->window), priv->window_width,
-                              priv->window_height);
+  gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(view));
+
+  return GTK_WINDOW(window);
+}
+
+// Implements GApplication::activate.
+static void fl_application_activate(GApplication* application) {
+  FlApplication* self = FL_APPLICATION(application);
+  FlApplicationPrivate* priv = FL_APPLICATION_GET_PRIVATE(self);
 
   g_autoptr(FlDartProject) project = fl_dart_project_new();
   fl_dart_project_set_dart_entrypoint_arguments(
@@ -101,7 +93,10 @@ static void fl_application_activate(GApplication* application) {
   g_signal_connect_swapped(view, "first-frame", G_CALLBACK(first_frame_cb),
                            self);
   gtk_widget_show(GTK_WIDGET(view));
-  gtk_container_add(GTK_CONTAINER(priv->window), GTK_WIDGET(view));
+
+  GtkWindow* window;
+  g_signal_emit(self, fl_application_signals[kSignalCreateWindow], 0, view,
+                &window);
 
   // Make the resources for the view so rendering can start.
   // We'll show the view when we have the first frame.
@@ -141,7 +136,6 @@ static void fl_application_dispose(GObject* object) {
   FlApplication* self = FL_APPLICATION(object);
   FlApplicationPrivate* priv = FL_APPLICATION_GET_PRIVATE(self);
 
-  g_clear_pointer(&priv->window_title, g_free);
   g_clear_pointer(&priv->dart_entrypoint_arguments, g_strfreev);
 
   G_OBJECT_CLASS(fl_application_parent_class)->dispose(object);
@@ -154,20 +148,20 @@ static void fl_application_class_init(FlApplicationClass* klass) {
   G_OBJECT_CLASS(klass)->dispose = fl_application_dispose;
 
   klass->register_plugins = fl_application_register_plugins;
+  klass->create_window = fl_application_create_window;
 
   fl_application_signals[kSignalRegisterPlugins] = g_signal_new(
       "register-plugins", fl_application_get_type(), G_SIGNAL_RUN_LAST,
-      G_STRUCT_OFFSET(FlApplicationClass, register_plugins), NULL, NULL,
-      g_cclosure_marshal_VOID__OBJECT, G_TYPE_NONE, 1,
-      fl_plugin_registry_get_type());
+      G_STRUCT_OFFSET(FlApplicationClass, register_plugins), nullptr, nullptr,
+      nullptr, G_TYPE_NONE, 1, fl_plugin_registry_get_type());
+  fl_application_signals[kSignalCreateWindow] = g_signal_new(
+      "create-window", fl_application_get_type(), G_SIGNAL_RUN_LAST,
+      G_STRUCT_OFFSET(FlApplicationClass, create_window),
+      g_signal_accumulator_first_wins, nullptr, nullptr, GTK_TYPE_WINDOW, 1,
+      fl_view_get_type());
 }
 
-static void fl_application_init(FlApplication* self) {
-  FlApplicationPrivate* priv = FL_APPLICATION_GET_PRIVATE(self);
-  priv->window_title = g_strdup("");
-  priv->window_width = 1280;
-  priv->window_height = 720;
-}
+static void fl_application_init(FlApplication* self) {}
 
 G_MODULE_EXPORT
 FlApplication* fl_application_new(const gchar* application_id,
@@ -176,22 +170,3 @@ FlApplication* fl_application_new(const gchar* application_id,
                                      "application-id", application_id, "flags",
                                      flags, nullptr));
 }
-
-G_MODULE_EXPORT
-void fl_application_set_default_window_title(FlApplication* self,
-                                             const gchar* window_title) {
-  g_return_if_fail(FL_IS_APPLICATION(self));
-  FlApplicationPrivate* priv = FL_APPLICATION_GET_PRIVATE(self);
-  g_free(priv->window_title);
-  priv->window_title = g_strdup(window_title);
-}
-
-G_MODULE_EXPORT
-void fl_application_set_default_window_size(FlApplication* self,
-                                            int width,
-                                            int height) {
-  g_return_if_fail(FL_IS_APPLICATION(self));
-  FlApplicationPrivate* priv = FL_APPLICATION_GET_PRIVATE(self);
-  priv->window_width = width;
-  priv->window_height = height;
-}

shell/platform/linux/public/flutter_linux/fl_application.h

@@ -40,6 +40,20 @@ struct _FlApplicationClass {
    */
   void (*register_plugins)(FlApplication* application,
                            FlPluginRegistry* registry);
+
+  /**
+   * FlApplication::create_window:
+   * @application: the application
+   * @view: the view to add to this window.
+   *
+   * The ::create_window signal is emitted when a needs to be created for a
+   * view. By handling this signal the application can create the appropriate
+   * window for the given view and set any window properties or additional
+   * widgets required.
+   *
+   * If this signal is not handled a standard GTK window will be created.
+   */
+  GtkWindow* (*create_window)(FlApplication* application, FlView* view);
 };
 
 /**
@@ -62,28 +76,6 @@ struct _FlApplicationClass {
 FlApplication* fl_application_new(const gchar* application_id,
                                   GApplicationFlags flags);
 
-/**
- * fl_application_set_default_window_title:
- * @application: an #FlApplication.
- * @window_title: window title text.
- *
- * Sets the title to apply to Flutter windows.
- */
-void fl_application_set_default_window_title(FlApplication* application,
-                                             const gchar* window_title);
-
-/**
- * fl_application_set_default_window_size:
- * @application: an #FlApplication.
- * @width: width in pixels or -1 to set the default width.
- * @height: height in pixels or -1 to set the default height.
- *
- * Sets the dimensions to apply to Flutter windows.
- */
-void fl_application_set_default_window_size(FlApplication* application,
-                                            int width,
-                                            int height);
-
 G_END_DECLS
 
 #endif  // FLUTTER_SHELL_PLATFORM_LINUX_PUBLIC_FLUTTER_LINUX_FL_APPLICATION_H_