Problems with layout

[Eric THIERRY <eric thierry finconsult fr>]

Hi there,

I have two problems with gtk_layout.

I create a layout that I add in a scrolled_window. Then I create some
buttons that I put in the layout, and I draw rectangles in a callback
function connected to the layout's expose event. For the moment,
everything's OK.

Now come the problems.

First problem:
When I scroll the scrolled_window, nothing happens. I have to resize my
window (with the mouse) to see the scrolling effect, which means to see
other buttons. (When I click on scrollbars arrows, the slider doesn't
move, I have to click in the trough to move it: is that a clue ??)

Second problem:
When I resize my window, I no longer see my rectangles. I see them for a
very short time in the increased portion of the window, but they
disappear quickly. To see them again, I have to mask my window with an
other one, or to iconify it and increase it. Do I have to use pixmap to
solve this ?

Thanks a lot.

Here's my code (inspired from a book, but similar to what I need)

#include <gtk/gtk.h>
#include <windows.h>
#include <stdio.h>

gint HandleExposeEvent (GtkWidget * widget, GdkEventExpose * event)
{
 GtkLayout *layout;

 gint i, j, imin, imax, jmin, jmax;

 layout = GTK_LAYOUT (widget);
 imin = (layout->xoffset + event->area.x) / 10;
 imax = (layout->xoffset + event->area.x + event->area.width + 9) / 10;

 jmin = (layout->yoffset + event->area.y) / 10;
 jmax = (layout->yoffset + event->area.y + event->area.height + 9) / 10;

 gdk_window_clear_area (widget->window, event->area.x, event->area.y,
        event->area.width, event->area.height);

 for (i=imin; i<imax; i++)
 {
  for (j=jmin; j<jmax; j++)
   {
    if ((i+j) % 2)
     gdk_draw_rectangle (layout->bin_window, widget->style->black_gc,
TRUE,
          ((10*i) - layout->xoffset), ((10*j) - layout->yoffset),
          1+i%10, 1+j%10);
   }
 }
 return TRUE;
}



void GtkLayoutDialog ()
{
 GtkWidget *layout, *scrolled_window, * label, * dialog_window;
 int i,j;
 char buf[128];

 dialog_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
 gtk_window_position (GTK_WINDOW (dialog_window), GTK_WIN_POS_MOUSE);
 gtk_widget_set_usize (dialog_window, 200, 200);

 gtk_signal_connect (GTK_OBJECT (dialog_window), "destroy",
GTK_SIGNAL_FUNC (gtk_main_quit), &dialog_window);

 scrolled_window = gtk_scrolled_window_new (NULL, NULL);
 gtk_container_add (GTK_CONTAINER (dialog_window), scrolled_window);

 layout = gtk_layout_new (NULL, NULL);
 gtk_layout_set_size (GTK_LAYOUT (layout), 1600, 12800);

 for (i=0; i<1600; i+=200)
 {
  for (j=0; j<12800; j+=200)
   {
    sprintf(buf, "%d %ld", i, j);
    label = gtk_button_new_with_label (buf);
    gtk_layout_put (GTK_LAYOUT (layout), label, i, j);
   }
 }

 gtk_container_add (GTK_CONTAINER (scrolled_window), layout);

 gtk_widget_set_events (layout, GDK_EXPOSURE_MASK );
 gtk_signal_connect (GTK_OBJECT (layout), "expose_event",
GTK_SIGNAL_FUNC (HandleExposeEvent), NULL);

 gtk_widget_show_all (dialog_window);
}

int __stdcall WinMain ( struct HINSTANCE__ *hInstance,
    struct HINSTANCE__ *hPrevInstance,
    char       *lpszCmdLine,
    int         nCmdShow)
{

 gtk_init (&__argc, &__argv);
 GtkLayoutDialog ();
 gtk_main ();
}

--
Salutations,

Eric THIERRY

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