[gtk+] widget: Don't assume opacity is 100%

[Benjamin Otte <otte src gnome org>]

commit 9a8a4a8b1479d004d1fb65a9ac6714318129bdad
Author: Benjamin Otte <otte redhat com>
Date:   Sat Sep 6 06:41:05 2014 +0200

    widget: Don't assume opacity is 100%
    
    ... just because there is no style context instantiated yet. Instead,
    instantiate a style context during realize() and ask it.
    
    Fixes problems with dim labels not being dimmed on first show.
    
    Testcase included.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=735240

 gtk/gtkwidget.c                           |   21 +++++++++------------
 testsuite/reftests/Makefile.am            |    3 +++
 testsuite/reftests/opacity-initial.css    |    3 +++
 testsuite/reftests/opacity-initial.ref.ui |   11 +++++++++++
 testsuite/reftests/opacity-initial.ui     |   29 +++++++++++++++++++++++++++++
 5 files changed, 55 insertions(+), 12 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 6f93a59..2593cbf 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -5527,9 +5527,7 @@ gtk_widget_realize (GtkWidget *widget)
       _gtk_widget_enable_device_events (widget);
       gtk_widget_update_devices_mask (widget, TRUE);
 
-      if (gtk_widget_is_toplevel (widget))
-       gdk_window_set_opacity (priv->window,
-                               priv->alpha / 255.0);
+      gtk_widget_update_alpha (widget);
 
       if (priv->context)
        gtk_style_context_set_scale (priv->context, gtk_widget_get_scale_factor (widget));
@@ -15913,6 +15911,7 @@ static void
 gtk_widget_update_alpha (GtkWidget *widget)
 {
   GtkWidgetPrivate *priv;
+  GtkStyleContext *context;
   gdouble opacity;
   guint8 alpha;
 
@@ -15920,15 +15919,13 @@ gtk_widget_update_alpha (GtkWidget *widget)
 
   alpha = priv->user_alpha;
 
-  if (priv->context)
-    {
-      opacity =
-       _gtk_css_number_value_get (_gtk_style_context_peek_property (priv->context,
-                                                                    GTK_CSS_PROPERTY_OPACITY),
-                                  100);
-      opacity = CLAMP (opacity, 0.0, 1.0);
-      alpha = round (priv->user_alpha * opacity);
-    }
+  context = gtk_widget_get_style_context (widget);
+  opacity =
+    _gtk_css_number_value_get (_gtk_style_context_peek_property (context,
+                                                                 GTK_CSS_PROPERTY_OPACITY),
+                               100);
+  opacity = CLAMP (opacity, 0.0, 1.0);
+  alpha = round (priv->user_alpha * opacity);
 
   if (alpha == priv->alpha)
     return;
diff --git a/testsuite/reftests/Makefile.am b/testsuite/reftests/Makefile.am
index 5f84f8c..0853a00 100644
--- a/testsuite/reftests/Makefile.am
+++ b/testsuite/reftests/Makefile.am
@@ -314,6 +314,9 @@ testdata = \
        opacity.css \
        opacity.ui \
        opacity.ref.ui \
+       opacity-initial.css \
+       opacity-initial.ref.ui \
+       opacity-initial.ui \
        overlay-no-main-widget.ref.ui \
        overlay-no-main-widget.ui \
        paned-undersized.css \
diff --git a/testsuite/reftests/opacity-initial.css b/testsuite/reftests/opacity-initial.css
new file mode 100644
index 0000000..611a8cd
--- /dev/null
+++ b/testsuite/reftests/opacity-initial.css
@@ -0,0 +1,3 @@
+GtkLabel {
+  opacity: 0;
+}
diff --git a/testsuite/reftests/opacity-initial.ref.ui b/testsuite/reftests/opacity-initial.ref.ui
new file mode 100644
index 0000000..1240351
--- /dev/null
+++ b/testsuite/reftests/opacity-initial.ref.ui
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Generated with glade 3.18.1 -->
+<interface>
+  <requires lib="gtk+" version="3.12"/>
+  <object class="GtkWindow" id="window1">
+    <property name="width_request">200</property>
+    <property name="height_request">100</property>
+    <property name="can_focus">False</property>
+    <property name="type">popup</property>
+  </object>
+</interface>
diff --git a/testsuite/reftests/opacity-initial.ui b/testsuite/reftests/opacity-initial.ui
new file mode 100644
index 0000000..9e02798
--- /dev/null
+++ b/testsuite/reftests/opacity-initial.ui
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Generated with glade 3.18.1 -->
+<interface>
+  <requires lib="gtk+" version="3.12"/>
+  <object class="GtkWindow" id="window1">
+    <property name="width_request">200</property>
+    <property name="height_request">100</property>
+    <property name="can_focus">False</property>
+    <property name="type">popup</property>
+    <child>
+      <object class="GtkOverlay" id="overlay1">
+        <property name="visible">True</property>
+        <property name="can_focus">False</property>
+        <child>
+          <placeholder/>
+        </child>
+        <child type="overlay">
+          <object class="GtkLabel" id="label1">
+            <property name="visible">True</property>
+            <property name="can_focus">False</property>
+            <property name="label" translatable="yes">I'm the invisible label.
+Incredible how you can
+see right through me.</property>
+          </object>
+        </child>
+      </object>
+    </child>
+  </object>
+</interface>