Re: [gtk-list] GtkPixmap / Imlib memory leak problem

[Erik Mouw <J A K Mouw its tudelft nl>]

On Mon, 17 May 1999 15:09:05 +0100, gtk-list@redhat.com (Dave Swegen) wrote:
> I'm having a problem with a hideous memory leak. In my program I use imlib
> to load an image, then convert the image data to a pixmap, which in turn is
> converted to a GtkPixmap (using gtk_pixmap_new()).

Imlib's picture cache can also look like a memory leak...

> This all works fine. The problem arises whenever I wish to replace the
> gtkpixmap with a newly generated pixmap. It would seem that the GdkPixmap
> info in the gtkpixmap struct is just cut loose every time I update, and
> I've been completly unable to figure out how to free the pixmap.

For normal GTK generated pixmaps, use gdk_pixmap_unref() and
gdk_bitmap_unref(), for Imlib, use gdk_imlib_free_pixmap() and
gdk_imlib_free_bitmap().

> The order of the program is something like this:
> 
> load_image() (using gdk_imlib)
> 
> update_and_render image()
> 
> display_pixmap()
> 
> I then have a callback function, which is run whnever the mouse is clicked.
> 
> The callback has the following sequence:
> 
> flood_fill_area()
> 
> update_and_render_image() <- Program size increases 3Mb every time called
> 
> display_pixmap()
> 
> The updating function looks like this:
> 
> void update_map(world *worldobj, gui_info * gui)
> {
>         GdkPixmap *pm;
> 
> /* worldobj->map is a GdkImlibImage */
>         gdk_imlib_changed_image(worldobj->map);
>         gdk_imlib_render(worldobj->map,
>                         worldobj->map->rgb_width,
>                         worldobj->map->rgb_height);
>         pm = gdk_imlib_move_image(worldobj->map);
> /* I suspect the old gdkpm is cut loose at the next line */
>         gui->map_pm = gtk_pixmap_new(pm, NULL);
>         worldobj->map_h = worldobj->map->rgb_height;
>         worldobj->map_w = worldobj->map->rgb_width;
>         gtk_fixed_put(GTK_FIXED(gui->fbox), gui->map_pm, 0, 0);
>         gtk_widget_show(gui->map_pm);
> }
> 
> According to the imlib docs gdk_imlib_free_pixmap should be called on all
> pixmaps created by imlib, but I have been unable to work out how to access
> the gdkpixmap which is held by the GtkPixmap (gui->map_pm, which is
> actually a GtkWidget).
> 
> Calling gtk_destroy_widget(gui->map_pm) either has no effect, or causes a
> segfault.
> 
> Anyway, I will appreciate any clarification on the matter.


In an application that displays uncompressed YUV 4:2:2 video data, I use:

  
void render_and_update(GtkWidget *pixmap, unsigned char *packedrgb,
                       int width, int height)
{
  GdkImlibImage *imlibimage;
  GdkPixmap *pmap;
  GdkBitmap *mask;

  /* sanity checks ... */
  assert(pixmap != NULL);
  assert(packedrgb != NULL);
  assert(width >= 0);
  assert(height >= 0);

  /* create an image from packed RGB data */
  imlibimage = gdk_imlib_create_image_from_data(packedrgb,
                                                NULL,
                                                width,
                                                height);

  /* render it */
  gdk_imlib_render(imlibimage, width, height);

  /* get pmap and mask to update pixmap */
  pmap = gdk_imlib_move_image(imlibimage);
  mask = gdk_imlib_move_mask(imlibimage);

  /* update pixmap */
  gtk_pixmap_set(GTK_PIXMAP(pixmap), pmap, mask);

  /* cleanup imlib stuff */
  gdk_imlib_kill_image(imlibimage);
  gdk_imlib_free_pixmap(pmap);
  gdk_imlib_free_bitmap(mask);
}



Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
Phone: +31-15-2785859  Fax: +31-15-2781843  Email J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/