[gtk+] widget: Give some meaning to "visible"

[Benjamin Otte <otte src gnome org>]

commit b495ce5446a0bbf2ed63b5880537779e4b123515
Author: Benjamin Otte <otte redhat com>
Date:   Tue Jan 8 14:56:02 2013 +0100

    widget: Give some meaning to "visible"
    
    GtkWidget::visible is required for the widget to:
    - have a preferred size other than 0/0
    - have a size allocated
    - return other values than { -1, -1, 1, 1 } from get_allocation()
    
    This is an experimental patch aiming to make concepts and behaviors
    inside GTK more concreate. GtkWidget::visible is now essentially what
    CSS does for "display: none".
    
    Note that if you want the effect of CSS's "visibility: hidden", you'll
    have to use a GtkNotebook with an empty page as the concept of reserving
    space but not drawing anything isn't supported natively in GTK.

 gtk/gtkwidget.c |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 53f5048..35fa755 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -4817,6 +4817,12 @@ gtk_widget_size_allocate (GtkWidget	*widget,
 
   g_return_if_fail (GTK_IS_WIDGET (widget));
 
+  if (!priv->visible)
+    {
+      g_print ("woot, invisible widget allocated!\n");
+      return;
+    }
+
   gtk_widget_push_verify_invariants (widget);
 
 #ifdef G_ENABLE_DEBUG
@@ -7494,7 +7500,17 @@ void
 _gtk_widget_set_visible_flag (GtkWidget *widget,
                               gboolean   visible)
 {
-  widget->priv->visible = visible;
+  GtkWidgetPrivate *priv = widget->priv;
+
+  priv->visible = visible;
+
+  if (!visible)
+    {
+      priv->allocation.x = -1;
+      priv->allocation.y = -1;
+      priv->allocation.width = 1;
+      priv->allocation.height = 1;
+    }
 }
 
 /**
@@ -13513,6 +13529,7 @@ gtk_widget_set_allocation (GtkWidget           *widget,
   GtkWidgetPrivate *priv;
 
   g_return_if_fail (GTK_IS_WIDGET (widget));
+  g_return_if_fail (gtk_widget_get_visible (widget));
   g_return_if_fail (allocation != NULL);
 
   priv = widget->priv;