[gtk+] builtin icon: set a baseline

[Matthias Clasen <matthiasc src gnome org>]

commit da30858ee416ec5a64579cb6a770efe44fb83789
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Jan 17 21:02:18 2016 -0500

    builtin icon: set a baseline
    
    Most uses of builtin icons (check and radio buttons,
    expanders, etc) are placed next to labels, so they should
    be properly positioned wrt to the baseline. Lacking anything
    better, give the builtin icons a baseline that places the
    center of the icon at the strikethrough position.

 gtk/gtkbuiltinicon.c |   35 +++++++++++++++++++++++++++--------
 1 files changed, 27 insertions(+), 8 deletions(-)
---
diff --git a/gtk/gtkbuiltinicon.c b/gtk/gtkbuiltinicon.c
index 8e543e5..8b99573 100644
--- a/gtk/gtkbuiltinicon.c
+++ b/gtk/gtkbuiltinicon.c
@@ -63,6 +63,10 @@ gtk_builtin_icon_get_preferred_size (GtkCssGadget   *gadget,
                                      gint           *natural_baseline)
 {
   GtkBuiltinIconPrivate *priv = gtk_builtin_icon_get_instance_private (GTK_BUILTIN_ICON (gadget));
+  GtkWidget *widget;
+  PangoContext *pango_context;
+  PangoFontMetrics *metrics;
+  int strikethrough;
   double min_size;
   guint property;
 
@@ -73,27 +77,42 @@ gtk_builtin_icon_get_preferred_size (GtkCssGadget   *gadget,
   min_size = _gtk_css_number_value_get (gtk_css_style_get_value (gtk_css_gadget_get_style (gadget), 
property), 100);
   if (min_size > 0.0)
     {
-      *minimum = *natural = 0;
-      return;
+      *minimum = *natural = min_size;
     }
-
-  if (priv->default_size_property)
+  else if (priv->default_size_property)
     {
       GValue value = G_VALUE_INIT;
 
       /* Do it a bit more complicated here so we get warnings when
-       * somebody sets a non-int proerty. */
+       * somebody sets a non-int proerty.
+       */
       g_value_init (&value, G_TYPE_INT);
       gtk_widget_style_get_property (gtk_css_gadget_get_owner (gadget),
                                      priv->default_size_property,
                                      &value);
       *minimum = *natural = g_value_get_int (&value);
       g_value_unset (&value);
-      return;
     }
+  else
+    {
+      *minimum = *natural = priv->default_size;
+    }
+
+  widget = gtk_css_gadget_get_owner (gadget);
+
+  pango_context = gtk_widget_get_pango_context (widget);
+  metrics = pango_context_get_metrics (pango_context,
+                                       pango_context_get_font_description (pango_context),
+                                       pango_context_get_language (pango_context));
+
+  strikethrough = pango_font_metrics_get_strikethrough_position (metrics);
+
+  if (minimum_baseline)
+    *minimum_baseline = *minimum * 0.5 + PANGO_PIXELS (strikethrough);
+  if (natural_baseline)
+    *natural_baseline = *minimum_baseline;
 
-  *minimum = priv->default_size;
-  *natural = priv->default_size;
+  pango_font_metrics_unref (metrics);
 }
 
 static void