evo/Gtk4-tutorial: GTK 4 tutorial for beginners

src/menu/menu2.c
117 строк4 KB
Toshio Sekiya
Update section 17 to 21.
03 янв 2023, 09:30
03 янв 2023, 09:30d4317f1
#include <gtk/gtk.h>

/* The provider below provides application wide CSS data. */
GtkCssProvider *provider;

static void
fullscreen_changed(GSimpleAction *action, GVariant *value, GtkWindow *win) {
  if (g_variant_get_boolean (value))
    gtk_window_maximize (win);
  else
    gtk_window_unmaximize (win);
  g_simple_action_set_state (action, value);
}

static void
color_activated(GSimpleAction *action, GVariant *parameter) {
  char *color = g_strdup_printf ("label.lb {background-color: %s;}", g_variant_get_string (parameter, NULL));
  /* Change the CSS data in the provider. */
  /* Previous data is thrown away. */
  gtk_css_provider_load_from_data (provider, color, -1);
  g_free (color);
  g_action_change_state (G_ACTION (action), parameter);
}

static void
remove_provider (GApplication *app, GtkCssProvider *provider) {
  GdkDisplay *display = gdk_display_get_default();
  
  gtk_style_context_remove_provider_for_display (display, GTK_STYLE_PROVIDER (provider));
  g_object_unref (provider);
}

static void
app_activate (GApplication *app) {
  GtkWindow *win = GTK_WINDOW (gtk_application_window_new (GTK_APPLICATION (app)));
  gtk_window_set_title (win, "menu2");
  gtk_window_set_default_size (win, 400, 300);

  GtkWidget *lb = gtk_label_new (NULL);
  gtk_widget_add_css_class (lb, "lb"); /* the class is used by CSS Selector */
  gtk_window_set_child (win, lb);

  GSimpleAction *act_fullscreen
    = g_simple_action_new_stateful ("fullscreen", NULL, g_variant_new_boolean (FALSE));
  g_signal_connect (act_fullscreen, "change-state", G_CALLBACK (fullscreen_changed), win);
  g_action_map_add_action (G_ACTION_MAP (win), G_ACTION (act_fullscreen));

  gtk_application_window_set_show_menubar (GTK_APPLICATION_WINDOW (win), TRUE);

  gtk_window_present (win);
}

static void
app_startup (GApplication *app) {
  GSimpleAction *act_color
    = g_simple_action_new_stateful ("color", g_variant_type_new("s"), g_variant_new_string ("red"));
  GSimpleAction *act_quit
    = g_simple_action_new ("quit", NULL);
  g_signal_connect (act_color, "activate", G_CALLBACK (color_activated), NULL);
  g_signal_connect_swapped (act_quit, "activate", G_CALLBACK (g_application_quit), app);
  g_action_map_add_action (G_ACTION_MAP (app), G_ACTION (act_color));
  g_action_map_add_action (G_ACTION_MAP (app), G_ACTION (act_quit));

  GMenu *menubar = g_menu_new ();
  GMenu *menu = g_menu_new ();
  GMenu *section1 = g_menu_new ();
  GMenu *section2 = g_menu_new ();
  GMenu *section3 = g_menu_new ();
  GMenuItem *menu_item_fullscreen = g_menu_item_new ("Full Screen", "win.fullscreen");
  GMenuItem *menu_item_red = g_menu_item_new ("Red", "app.color::red");
  GMenuItem *menu_item_green = g_menu_item_new ("Green", "app.color::green");
  GMenuItem *menu_item_blue = g_menu_item_new ("Blue", "app.color::blue");
  GMenuItem *menu_item_quit = g_menu_item_new ("Quit", "app.quit");

  g_menu_append_item (section1, menu_item_fullscreen);
  g_menu_append_item (section2, menu_item_red);
  g_menu_append_item (section2, menu_item_green);
  g_menu_append_item (section2, menu_item_blue);
  g_menu_append_item (section3, menu_item_quit);
  g_object_unref (menu_item_red);
  g_object_unref (menu_item_green);
  g_object_unref (menu_item_blue);
  g_object_unref (menu_item_fullscreen);
  g_object_unref (menu_item_quit);

  g_menu_append_section (menu, NULL, G_MENU_MODEL (section1));
  g_menu_append_section (menu, "Color", G_MENU_MODEL (section2));
  g_menu_append_section (menu, NULL, G_MENU_MODEL (section3));
  g_menu_append_submenu (menubar, "Menu", G_MENU_MODEL (menu));

  gtk_application_set_menubar (GTK_APPLICATION (app), G_MENU_MODEL (menubar));

  provider = gtk_css_provider_new ();
  /* Initialize the css data */
  gtk_css_provider_load_from_data (provider, "label.lb {background-color: red;}", -1);
  /* Add CSS to the default GdkDisplay. */
  GdkDisplay *display = gdk_display_get_default ();
  gtk_style_context_add_provider_for_display (display, GTK_STYLE_PROVIDER (provider),
                                              GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
  g_signal_connect (app, "shutdown", G_CALLBACK (remove_provider), provider);
}

#define APPLICATION_ID "com.github.ToshioCP.menu2"

int
main (int argc, char **argv) {
  GtkApplication *app;
  int stat;

  app = gtk_application_new (APPLICATION_ID, G_APPLICATION_DEFAULT_FLAGS);
  g_signal_connect (app, "startup", G_CALLBACK (app_startup), NULL);
  g_signal_connect (app, "activate", G_CALLBACK (app_activate), NULL);

  stat =g_application_run (G_APPLICATION (app), argc, argv);
  g_object_unref (app);
  return stat;
}