[gtk+] stylecontext: Only create transitions conditionally

[Benjamin Otte <otte src gnome org>]

commit 4a281edc872be418824fabf07b074b1a449a2e7a
Author: Benjamin Otte <otte redhat com>
Date:   Mon Sep 17 11:30:21 2012 +0200

    stylecontext: Only create transitions conditionally
    
    While regular animations should always be created, transitions should
    not. This patch allows to express this by passing NULL as the values to
    transition from.
    
    It also adds a gtk_style_context_should_create_transitions() function
    that returns TRUE when transitions should be created.

 gtk/gtkcsscomputedvalues.c |    3 ++-
 gtk/gtkstylecontext.c      |   23 ++++++++++++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkcsscomputedvalues.c b/gtk/gtkcsscomputedvalues.c
index 7ec040e..cd2f66b 100644
--- a/gtk/gtkcsscomputedvalues.c
+++ b/gtk/gtkcsscomputedvalues.c
@@ -492,7 +492,8 @@ _gtk_css_computed_values_create_animations (GtkCssComputedValues *values,
                                             GtkCssComputedValues *source,
                                             GtkStyleContext      *context)
 {
-  gtk_css_computed_values_create_css_transitions (values, timestamp, source);
+  if (source != NULL)
+    gtk_css_computed_values_create_css_transitions (values, timestamp, source);
   gtk_css_computed_values_create_css_animations (values, timestamp, context);
 }
 
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index e42ac88..b06d4d8 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -3077,6 +3077,27 @@ gtk_style_context_needs_full_revalidate (GtkStyleContext  *context,
     return FALSE;
 }
 
+static gboolean
+gtk_style_context_should_create_transitions (GtkStyleContext *context)
+{
+  GtkStyleContextPrivate *priv;
+  gboolean animate;
+
+  priv = context->priv;
+
+  if (priv->widget == NULL)
+    return FALSE;
+
+  if (!gtk_widget_get_mapped (priv->widget))
+    return FALSE;
+
+  g_object_get (gtk_widget_get_settings (context->priv->widget),
+                "gtk-enable-animations", &animate,
+                NULL);
+
+  return animate;
+}
+
 void
 _gtk_style_context_validate (GtkStyleContext  *context,
                              gint64            timestamp,
@@ -3144,7 +3165,7 @@ _gtk_style_context_validate (GtkStyleContext  *context,
 
           _gtk_css_computed_values_create_animations (data->store,
                                                       timestamp,
-                                                      current->store,
+                                                      gtk_style_context_should_create_transitions (context) ? current->store : NULL,
                                                       context);
           if (_gtk_css_computed_values_is_static (data->store))
             change &= ~GTK_CSS_CHANGE_ANIMATE;