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.

diff --git a/gtk/gtksizegroup.c b/gtk/gtksizegroup.c
index 3385e04131907c6c3c086301b006b64e07a0186e..b9e2ac36a36b18b726b75feabb8660f9fa9fbc38 100644 (file)
--- 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)
     {