Unsolved clipping problem

[Tintin72 <lucas sanner free fr>]

Hi,

I'm programming GTK under Windows Xp and I have a clipping problem I just
can't solve.
My application consist in a window with a drawing area wrapped by a
scrolled_window.
So when I move the slider a little fast I get clipping effect on the edges
(up or down) of the drawing area.
Maybe it's the way I handle the drawing area or the way I handle the
scrolled window (or both) that cause this clipping effect ?
To illustrated the pb, I build a simple example where text lines are drawed
in the drawing area.

#include <gtk/gtk.h> 
#define WIDTH 500 
#define HEIGHT 300 

typedef struct APPLICATION 
{ 
  GtkWidget *pWin; 
  GtkWidget *pDrawArea; 
  GtkWidget *pVBox; 
  GtkWidget *pScrollBar; 

}APPLICATION; 

GdkPixmap *pPixmap = NULL; 

static gboolean configure_event(GtkWidget *widget, GdkEventConfigure *event) 
{ 
  if(pPixmap) g_object_unref(pPixmap); 

  pPixmap = gdk_pixmap_new(widget->window, widget->allocation.width, 
                                          widget->allocation.height, -1); 
  gdk_draw_rectangle (pPixmap, widget->style->white_gc, TRUE, 0, 0, 
                                                    
widget->allocation.width, 
                                                    
widget->allocation.height); 
  return TRUE; 
} 

static gboolean draw_cb(GtkWidget *drawArea, GdkEventExpose *event, gpointer
userData) 
{ 
   gdk_draw_drawable(drawArea->window,
drawArea->style->fg_gc[GTK_WIDGET_STATE (drawArea)], 
                                        pPixmap, event->area.x,
event->area.y, 
                                        event->area.x, event->area.y, 
                                        event->area.width,
event->area.height); 

   PangoContext *pContext = gtk_widget_get_pango_context(drawArea); 
   PangoLayout *pLayout = pango_layout_new(pContext); 
    int i; 
    for(i = 0; i < 30; i++) 
    { 
      pango_layout_set_text (pLayout, "Test clipping", 14); 
     gdk_draw_layout (drawArea->window,
drawArea->style->fg_gc[GTK_WIDGET_STATE(drawArea)], 
                                                                         0,i
* 15, pLayout); 
    } 
   g_object_unref(pLayout); 
   return FALSE; 
} 

int main (int argc, char *argv[]) 
{ 
  APPLICATION myApp; 
  gtk_init(&argc, &argv); 

  myApp.pWin = gtk_window_new(GTK_WINDOW_TOPLEVEL); 
  gtk_window_set_default_size(GTK_WINDOW(myApp.pWin), WIDTH, HEIGHT); 
  g_signal_connect(G_OBJECT(myApp.pWin), "destroy",
G_CALLBACK(gtk_main_quit), NULL); 
  myApp.pVBox = gtk_vbox_new(FALSE, 0); 
  gtk_container_add(GTK_CONTAINER(myApp.pWin), myApp.pVBox); 
  myApp.pScrollBar = gtk_scrolled_window_new(NULL,NULL); 
  gtk_box_pack_start(GTK_BOX(myApp.pVBox), myApp.pScrollBar, TRUE, TRUE, 0); 
  myApp.pDrawArea = gtk_drawing_area_new (); 
  gtk_box_pack_start(GTK_BOX(myApp.pScrollBar), myApp.pDrawArea, TRUE, TRUE,
0); 
  gtk_widget_set_size_request (myApp.pDrawArea,
myApp.pWin->allocation.width, 500); 
 
g_signal_connect(G_OBJECT(myApp.pDrawArea),"expose_event",G_CALLBACK(draw_cb),
&myApp); 
  g_signal_connect(G_OBJECT(myApp.pDrawArea),"configure_event", G_CALLBACK
(configure_event), NULL); 
 
gtk_scrolled_window_add_with_viewport(GTK_SCROLLED_WINDOW(myApp.pScrollBar),
myApp.pDrawArea); 
  gtk_window_set_title(GTK_WINDOW(myApp.pWin), "GTK-Win"); 
  gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(myApp.pScrollBar),
GTK_POLICY_NEVER,GTK_POLICY_AUTOMATIC); 

  gtk_widget_show_all (myApp.pWin); 
  gtk_main (); 
  return 0; 
}

A guy on a forum compiled my code on his system (Linux probably) and
everything seems ok (no clipping at all).
So I really don't understand.
I builded many applications with different GUIs, and I've never had this
kind of problem.
Is there any incompatibilities between GTK and Windows ?

Can somebody help me ?

Thanks for advance

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