[gtk+] sizegroups: Use is_visible() instead of get_mapped() for visibility

[Benjamin Otte <otte src gnome org>]

commit be1bde91112c80ddc475547db0d5cfabdff7f046
Author: Benjamin Otte <otte redhat com>
Date:   Fri Nov 2 00:44:30 2012 +0100

    sizegroups: Use is_visible() instead of get_mapped() for visibility
    
    The current approach of using gtk_widget_get_mapped() is broken:
    The usual steps taken when showing a window are:
    (1) request the sizes
    (2) allocate the sizes
    (3) show the window in the allocated size
    
    Showing the window with a random size between steps (1) and (2) would of
    course
    result in extra work and potential flickering when the widgets get
    resized to
    their proper sizes.
    
    However, as GtkSizeGroup::ignore-hidden uses gtk_widget_get_mapped() to
    determine visibility for a widget, the following will happen:
    (1) the widget will request a 0 size
    (2) the widget will be allocated a 0 size
    (3) the widget will be too small when it is shown
    
    gtk_widget_get_visible() however is set in advance. Note that toggling
    visibility also causes a gtk-widget_queue_resize() call already so we
    take care of changes in here automatically.

 gtk/gtksizegroup.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtksizegroup.c b/gtk/gtksizegroup.c
index 3385e04..b9e2ac3 100644
--- a/gtk/gtksizegroup.c
+++ b/gtk/gtksizegroup.c
@@ -165,7 +165,7 @@ add_widget_to_closure (GtkWidget       *widget,
 
   *widgets = g_slist_prepend (*widgets, widget);
   _gtk_widget_set_sizegroup_visited (widget, TRUE);
-  hidden = !gtk_widget_get_mapped (widget);
+  hidden = !gtk_widget_is_visible (widget);
 
   for (tmp_groups = _gtk_widget_get_sizegroups (widget); tmp_groups; tmp_groups = tmp_groups->next)
     {