GTK+ Schriftgröße ändern

Es scheint ein wenig umständlich zu sein. Scheinbar sollte es über die 
Textattribute funktionieren:

http://library.gnome.org/devel/gtk/unstable/GtkTextTag.html

und dann dort die Eigenschaft verändern:

http://library.gnome.org/devel/gtk/unstable/GtkTextTag.html#GtkTextTag--scale

ODER, sollte es dies sein...????

--

#include <gtk/gtk.h>

// Nicht so schön...
GtkWidget *text_view;

void
on_window_destroy (GtkWidget *widget, gpointer data)
{
  gtk_main_quit ();
}

/* Callback for close button */
void
on_button_clicked (GtkWidget *button, GtkTextBuffer *buffer)
{
  static int flag=0;
  PangoFontDescription *font_desc;

  if (flag==0) {
    font_desc = pango_font_description_from_string ("mono 30");
    flag=1;
  }
  else {
    font_desc = pango_font_description_from_string ("mono 10");
    flag=0;
  }
  gtk_widget_modify_font (text_view, font_desc);
  pango_font_description_free (font_desc);
}

int
main(int argc, char *argv[])
{
  GtkWidget *window;
  GtkWidget *vbox;
  GtkWidget *button;
  GtkTextBuffer *buffer;


  gtk_init (&argc, &argv);

  /* Create a Window. */
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW (window), "Simple Multiline Text 
Input");

  /* Set a decent default size for the window. */
  gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
  g_signal_connect (G_OBJECT (window), "destroy",
                    G_CALLBACK (on_window_destroy),
                    NULL);

  vbox = gtk_vbox_new (FALSE, 2);
  gtk_container_add (GTK_CONTAINER (window), vbox);

  /* Create a multiline text widget. */
  text_view = gtk_text_view_new ();
  gtk_box_pack_start (GTK_BOX (vbox), text_view, 1, 1, 0);

  /* Obtaining the buffer associated with the widget. */
  buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view));

  /* Set the default buffer text. */
  gtk_text_buffer_set_text (buffer, "Hello Text View!", -1);

  /* Create a close button. */
  button = gtk_button_new_with_label ("Change");
  gtk_box_pack_start (GTK_BOX (vbox), button, 0, 0, 0);
  g_signal_connect (G_OBJECT (button), "clicked",
                    G_CALLBACK (on_button_clicked),
                    buffer);

  gtk_widget_show_all (window);

  gtk_main ();
  return 0;
}

Am schoensten ist es mit .rc Files, dann kann man solche Attribute 
naemlich auch ohne neukompilieren aendern.

http://www.gtk.org/tutorial1.2/gtk_tut-21.html

kurze Zusammenfassung:
- bla.rc File mit zB sowas wie

style "test"
{
  font_name = "DejaVuSans 36"
}

- im Programm sowas wie

gtk_rc_parse("bla.rc");

gtk_widget_set_name(GTK_WIDGET(blubb), "test");

Damit lassen sich auch noch Hintergrundbilder, Farben etc aendern.