Re: Fwd: Resize and place a background image (Expose Event)

[Rúben Rodrigues <ruben_gr live com pt>]

Thank you very much!!

I'm not sure if i have to do this every time an expose event occurs.. I 
think that i just need on start of application.. But i test on start of 
application, i i don't have widget->allocation values, to make the resize..

Now, application crash after start, but i think that is because i make 
the unref of pixbuf, and in next expose event, fails (i think)...

GdkPixbuf-CRITICAL **: gdk_pixbuf_scale_simple: assertion 'GDK_IS_PIXBUF 
(src)' failed
GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT 
(object)' failed
Gdk-CRITICAL **: IA__gdk_pixbuf_render_pixmap_and_mask_for_colormap: 
assertion 'GDK_IS_PIXBUF (pixbuf)' failed
GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT 
(object)' failed

Às 09:54 de 02/03/2017, Gabriele Greco escreveu:
> > This works, but application blocks after a while..
> I'm quite sure the problem is that you are leaking at least 2 pixbuf and a
> pixmap for every expose event your app receives, and anyway, are you sure
> you have to do it every time an expose event is thrown and not only when
> the window is resized (configure_event)?
>
>
> >       pixbuf = gdk_pixbuf_scale_simple(pixbuf, widget->allocation.width,
> If the original pixbuf has been created just for this operation, this call
> leaks a pixbuf object, you shoud do something like:
>
> GdkPixbuf *scaled = gdk_pixbuf_scale_simple(pixbuf,
> widget->allocation.width, [...]
> g_object_unref(pixbuf);
>
>
> > widget->allocation.height, GDK_INTERP_BILINEAR);
> >       gdk_pixbuf_render_pixmap_and_mask (pixbuf, &background, NULL, 0);
> At this point you leak the second pixbuf, use for instance:
> g_object_unref(scaled);
>
>
> >       style->bg_pixmap[0] = background;
> >       gtk_widget_set_style (GTK_WIDGET(widget), GTK_STYLE(style));
> I'm quite sure set_style will increase reference count for 'background', so
> after this call you should unref that pixmap:
>
> g_object_unref(background);
>
> You'll receive runtime errors if one of my statements here is not correct,
> it's better to add a not needed unref in development and fix it that
> release a version that leaks memory.


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