[gtk+/wip/hires-icons: 2/9] gtk: add gtk_widget_get_scale_factor()

[Carlos Garnacho <carlosg src gnome org>]

commit 06ac8109a0f1309151ab5494ef044507c03b3e2c
Author: Michael Natterer <mitch gimp org>
Date:   Fri Feb 15 15:35:13 2013 +0100

    gtk: add gtk_widget_get_scale_factor()

 gtk/gtkwidget.c |   20 ++++++++++++++++++++
 gtk/gtkwidget.h |    1 +
 2 files changed, 21 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 6ab93eb..b5ce4e5 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -9925,6 +9925,26 @@ gtk_widget_has_screen (GtkWidget *widget)
   return (gtk_widget_get_screen_unchecked (widget) != NULL);
 }
 
+gdouble
+gtk_widget_get_scale_factor (GtkWidget *widget)
+{
+  GtkWidget *toplevel;
+
+  g_return_val_if_fail (GTK_IS_WIDGET (widget), 1.0);
+
+  toplevel = gtk_widget_get_toplevel (widget);
+  if (toplevel && toplevel != widget)
+    return gtk_widget_get_scale_factor (toplevel);
+
+  if (gtk_widget_get_realized (widget))
+    return gdk_window_get_scale_factor (gtk_widget_get_window (widget));
+
+  /* else fall back to something that is more likely to be right than
+   * just returning 1.0:
+   */
+  return gdk_screen_get_monitor_scale_factor (gtk_widget_get_screen (widget), 0);
+}
+
 /**
  * gtk_widget_get_display:
  * @widget: a #GtkWidget
diff --git a/gtk/gtkwidget.h b/gtk/gtkwidget.h
index 25247d5..d6d49f7 100644
--- a/gtk/gtkwidget.h
+++ b/gtk/gtkwidget.h
@@ -854,6 +854,7 @@ GDK_AVAILABLE_IN_ALL
 GdkScreen *   gtk_widget_get_screen      (GtkWidget *widget);
 GDK_AVAILABLE_IN_ALL
 gboolean      gtk_widget_has_screen      (GtkWidget *widget);
+gdouble       gtk_widget_get_scale_factor (GtkWidget *widget);
 GDK_AVAILABLE_IN_ALL
 GdkDisplay *  gtk_widget_get_display     (GtkWidget *widget);
 GDK_AVAILABLE_IN_ALL