Date: Fri, 05 Jan 2001 00:23:18 -0800
From: Chris Hecker <checker at d6.com>
Subject: Re: resize event?
To: lablgtk at kaba.or.jp
Message-id: <4.3.2.7.2.20010105002151.00baf5c0 at shell16.ba.best.com>
MIME-version: 1.0
Content-type: text/plain; charset="us-ascii"


[Resent to the list to keep people updated...Jacques and I had a private thread going.]

>It is possible that events work differently on windows and X11.
>Try using other events, like configure,  in place of expose, this may
>work better.

I tried configure, but that didn't work either.  Which one is supposed to be called on resize?

Now that I've looked at it closer, it looks like the image does get repainted on resize, it's just that the window gets cleared immediately afterwards.

I decided to dig up a gtk sample app that's similar.  I've attached it below (I also put image.ml in there).  It works correctly, and the image is rock solid.  So, it doesn't look like a GTK bug.  Any ideas?

Chris



#include <gtk/gtk.h>

#define IMAGE_WIDTH     256
#define IMAGE_HEIGHT    256

guchar rgbbuf[IMAGE_WIDTH * IMAGE_HEIGHT * 3];

gboolean on_darea_expose (GtkWidget *widget,
                          GdkEventExpose *event,
                          gpointer user_data);

int
main (int argc, char *argv[])
{
  GtkWidget *window, *darea;
  gint x, y;
  guchar *pos;

  gtk_init (&argc, &argv);
  gdk_rgb_init();
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  darea = gtk_drawing_area_new();
  gtk_drawing_area_size (GTK_DRAWING_AREA (darea), IMAGE_WIDTH, IMAGE_HEIGHT);
  gtk_container_add (GTK_CONTAINER (window), darea);
  gtk_signal_connect (GTK_OBJECT (darea), "expose-event",
                      GTK_SIGNAL_FUNC (on_darea_expose), NULL);
  gtk_widget_show_all (window);

  /* Set up the RGB buffer. */
  pos = rgbbuf;
  for (y = 0; y < IMAGE_HEIGHT; y++)
    {
      for (x = 0; x < IMAGE_WIDTH; x++)
        {
          *pos++ = x - x % 32;                  /* Red. */
          *pos++ = (x / 32) * 4 + y - y % 32;   /* Green. */
          *pos++ = y - y % 32;                  /* Blue. */
        }
    }

  gtk_main();
  return 0;
}

gboolean
on_darea_expose (GtkWidget *widget,
                GdkEventExpose *event,
                gpointer user_data)
{
  gdk_draw_rgb_image (widget->window, widget->style->fg_gc[GTK_STATE_NORMAL],
                      0, 0, IMAGE_WIDTH, IMAGE_HEIGHT,
                      GDK_RGB_DITHER_MAX, rgbbuf, IMAGE_WIDTH * 3);
}



(* $Id: image.ml,v 1.6 2000/06/06 03:51:04 garrigue Exp $ *)

open GMain
open Gdk

(* load image *)
let buf = String.create (256*256*3)
let ic = open_in_bin "image256x256.rgb"
let _ = 
  really_input ic ~buf:buf ~pos:0 ~len:(256*256*3);
  close_in ic

let rgb_at x y =
  let offset = (y * 256 + x) * 3 in
  (int_of_char buf.[offset  ],
   int_of_char buf.[offset+1],
   int_of_char buf.[offset+2])

(* let id = Thread.create GtkThread.main () *)

(* Choose a visual appropriate for RGB *)
let _ =
  Gdk.Rgb.init ();
  GtkBase.Widget.set_default_visual (Gdk.Rgb.get_visual ());
  GtkBase.Widget.set_default_colormap (Gdk.Rgb.get_cmap ())

(* We need show: true because of the need of visual *)
let window = GWindow.window ~show:true ~width: 256 ~height: 256 ()

let visual = window#misc#visual

let color_create = Truecolor.color_creator visual

let w = window#misc#window
let drawing = new GDraw.drawable w

let _ =
  window#connect#destroy ~callback:Main.quit;

  let image =
    Image.create ~kind: `FASTEST ~visual: visual ~width: 256 ~height: 256
  in

  let draw () =
    for x = 0 to 255 do
      for y = 0 to 255 do
        let r,g,b = rgb_at x y in
        Image.put_pixel image ~x: x ~y: y 
          ~pixel: (color_create ~red: (r * 256) ~green: (g * 256) ~blue: (b * 256))
      done
    done 
  in
 
  let display () =
    drawing#put_image image ~xsrc:0 ~ysrc:0 ~xdest:0 ~ydest:0 ~width:256 ~height:256
  in

  draw (); 

  window#event#connect#after#expose ~callback:
    begin fun _ ->
      display (); false
    end;
  (* Thread.join id *)

  window#show ();
  Main.main ()