Drawing lines in a gtk_layout

[Jose Fernando Diago <jdiago escher puj edu co>]

Hello.

I'm actually developing some kind of editor with icons and connections
between them.

I choose the gtk_layout to put my icons because it allows me to put them
in any x,y position and it doesn't need to be redrawn. But now I trying to
draw lines in the layout to connect the icons but the lines never get
drawn. I've also tried with the gtk_fixed and the lines get drawn on it
pretty easy, but it needs to be redrawn.

Anyway has anyone acomplished succesfully the task of drawing lines on a
gtk_layout using gdk_draw_line()?

Here's the code I'm using right now (sorry about the global variables, is
just a test program). Please note, if I comment the line where I create
the layout
  drawing = gtk_layout_new (NULL, NULL);
and uncomment the following line
  drawing = gtk_fixed_new ();

then things work just fine

Anyway, here is the code:

#include <gtk/gtk.h>
int xini, yini, xfin, yfin;

gboolean bpress_event( GtkWidget *widget, GdkEventButton *event, gpointer
data )
{

  printf ("\nbutton press ok");
  xini=(int)event->x;
  yini=(int)event->y;

  return FALSE;
}

gboolean brelease_event( GtkWidget *widget, GdkEventButton *event,
gpointer data)
{

  printf ("\nbutton release ok");

  xfin=(int)event->x;
  yfin=(int)event->y;

  gdk_draw_line(widget->window, widget->style->black_gc, xini, yini, xfin, 
yfin);

  return FALSE;
}

int main(int argc, char **argv)
{
  GtkWidget *drawing;
  GtkWidget *vbox;
  GtkWidget  *mainwin;

... stuff

  mainwin = gtk_window_new(GTK_WINDOW_TOPLEVEL);

... setting the main window properties and close event, etc...

  vbox = gtk_vbox_new(FALSE, 0);
  gtk_container_add(GTK_CONTAINER(mainwin), vbox);

  drawing = gtk_layout_new (NULL, NULL);

//  drawing = gtk_fixed_new ();

  gtk_box_pack_start(GTK_BOX(vbox), drawing, TRUE, TRUE, 0);
    

  gtk_signal_connect (GTK_OBJECT (drawing), "button_press_event",
		      GTK_SIGNAL_FUNC(bpress_event), NULL);

  gtk_signal_connect (GTK_OBJECT (drawing), "button_release_event",
		      GTK_SIGNAL_FUNC(brelease_event), NULL);

  gtk_widget_set_events (drawing, GDK_BUTTON_PRESS_MASK
			 | GDK_BUTTON_RELEASE_MASK);


  /* Let's show the drawing (layout/eventbox) */
  gtk_widget_show(drawing);
  
  gtk_widget_show(vbox);

  /* Let's show the Main Window */
  gtk_widget_show(mainwin);	

  
  /* Enter main gtk loop. */
  gtk_main();
  
  return(0);
}