Gtk CSS Example

#include <gtk/gtk.h>

static void
activate (GtkApplication* app,
          gpointer        user_data)
{
  GtkWidget *window, *box, *combo;
  GtkCssProvider *provider;
  GtkListStore *liststore;
  GtkCellRenderer *column;

  window = gtk_application_window_new (app);
  gtk_window_set_title (GTK_WINDOW (window), "Window");
  gtk_window_set_default_size (GTK_WINDOW (window), 600, 400);

  box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
  gtk_container_add (GTK_CONTAINER (window), box);

  liststore = gtk_list_store_new(3, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_STRING);
  for(int i=0; i<10; i++) {
      gtk_list_store_insert_with_values(liststore, NULL, -1, 0, "Default", 1, "white", 2, "black", -1);
  }
  combo = gtk_combo_box_new_with_model(GTK_TREE_MODEL(liststore));
  g_object_unref(liststore);
  column = gtk_cell_renderer_text_new();
  gtk_cell_layout_pack_start(GTK_CELL_LAYOUT(combo), column, TRUE);
  gtk_cell_layout_set_attributes(GTK_CELL_LAYOUT(combo), column, "text", 0, "foreground", 1, "background", 2, NULL);

  provider = gtk_css_provider_new ();
  gtk_css_provider_load_from_data (provider, "menuitem { background: #000; } menuitem:hover { background: #FFF; } .combo { background: #000; }", -1, NULL);
  gtk_style_context_add_provider (
    GTK_STYLE_CONTEXT (gtk_widget_get_style_context (GTK_WIDGET (combo))),
    GTK_STYLE_PROVIDER (provider),
    GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);

  gtk_style_context_add_provider_for_screen (gtk_widget_get_screen (combo),
                                             GTK_STYLE_PROVIDER (provider),
                                             GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);

  gtk_container_add (GTK_CONTAINER (box), combo);

  gtk_widget_show_all (window);
}

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

  app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
  g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
  status = g_application_run (G_APPLICATION (app), argc, argv);
  g_object_unref (app);

  return status;
}