Please help: how to call xilb drawing functions to draw on GTK drawing areas?

[Ke Jin <jinkea gmail com>]

Dear All,

I am trying to use xlib function XDrawArc() to draw on a GTK drawing  
area but it doesn't work, while the GDK function gdk_draw_arc() works  
perfect. Does anyone know why? Below are my code:

#include <string.h>
#include <X11/Xlib.h>
#include <X11/keysym.h>
#include <gtk/gtk.h>
#include <gdk/gdkx.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>

void destroy (GtkWidget *widget, gpointer *data)
{
    printf("in destory\n");
    gtk_main_quit ();
}

gboolean expose_event_callback (GtkWidget *widget, GdkEventExpose  
*event, gpointer data)
{
   //this function works fine
   /*gdk_draw_arc (widget->window,
                widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
                TRUE,
                0, 0, widget->allocation.width, widget- 
>allocation.height,
                0, 64 * 360);*/

    /*below xlib drawing function doesn't work*/
    GdkGC *gc = widget->style->fg_gc[GTK_WIDGET_STATE (widget)];
    XDrawArc(GDK_DRAWABLE_XDISPLAY(widget->window),  
GDK_DRAWABLE_XID(widget->window), GDK_GC_XGC(gc), 0, 0, widget- 
>allocation.width, widget->allocation.height,0, 64 * 360);

  return TRUE;
}


int main(int argc, char* argv[])
{
    GtkWidget *gtkWin;
    GtkWidget *drawArea;
    GtkWidget *button;
    GtkWidget *mybox;

    XEvent e;
    pid_t pid;
    Bool child = FALSE;


    gtk_init (&argc, &argv);

    //initialize
    gtkWin = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    drawArea = gtk_drawing_area_new();
    button = gtk_button_new_with_label("Button");
    mybox = gtk_hbox_new(FALSE,10);

    //attributes setup
    gtk_widget_set_size_request(drawArea,100,100);


    //layout
    gtk_box_pack_start(GTK_BOX(mybox),button,TRUE,FALSE,0);
    gtk_box_pack_start(GTK_BOX(mybox),drawArea,TRUE,FALSE,0);
    gtk_container_add (GTK_CONTAINER (gtkWin), mybox);


    /*Events and Signals connect*/
    gtk_signal_connect (GTK_OBJECT (button), "clicked",
                        GTK_SIGNAL_FUNC (destroy),NULL);

    g_signal_connect (G_OBJECT (drawArea), "expose_event",
                    G_CALLBACK (expose_event_callback),NULL);



    /*show widgets*/

    gtk_widget_show(button);
    gtk_widget_show(drawArea);
    gtk_widget_show(mybox);
    gtk_widget_show(gtkWin);

    gtk_main();

    return 0;
}