GtkPaned: Add a "wide-handle" property

This can be used by applications to indicate that a paned is expected
to be actively used by the users for configuring the UI, and needs
a prominent handle.

https://bugzilla.gnome.org/show_bug.cgi?id=738860

docs/reference/gtk/gtk3-sections.txt

@@ -2593,6 +2593,8 @@ gtk_paned_get_child2
 gtk_paned_set_position
 gtk_paned_get_position
 gtk_paned_get_handle_window
+gtk_paned_set_wide_handle
+gtk_paned_get_wide_handle
 <SUBSECTION Standard>
 GTK_PANED
 GTK_IS_PANED
@@ -6053,6 +6055,7 @@ GTK_STYLE_CLASS_TROUGH
 GTK_STYLE_CLASS_VERTICAL
 GTK_STYLE_CLASS_VIEW
 GTK_STYLE_CLASS_WARNING
+GTK_STYLE_CLASS_WIDE
 GTK_STYLE_REGION_COLUMN
 GTK_STYLE_REGION_COLUMN_HEADER
 GTK_STYLE_REGION_ROW

gtk/gtkpaned.c

@@ -138,7 +138,8 @@ enum {
   PROP_POSITION,
   PROP_POSITION_SET,
   PROP_MIN_POSITION,
-  PROP_MAX_POSITION
+  PROP_MAX_POSITION,
+  PROP_WIDE_HANDLE
 };
 
 enum {
@@ -380,6 +381,23 @@ gtk_paned_class_init (GtkPanedClass *class)
                                                      0, G_MAXINT, G_MAXINT,
                                                      GTK_PARAM_READABLE|G_PARAM_EXPLICIT_NOTIFY));
 
+  /**
+   * GtkPaned:wide-handle:
+   *
+   * Setting this property to %TRUE indicates that the paned needs
+   * to provide stronger visual separation (e.g. because it separates
+   * between two notebooks, whose tab rows would otherwise merge visually).
+   *
+   * Since: 3.16 
+   */
+  g_object_class_install_property (object_class,
+                                   PROP_WIDE_HANDLE,
+                                   g_param_spec_boolean ("wide-handle",
+                                                         P_("Wide Handle"),
+                                                         P_("Whether the paned should have a prominent handle"),
+                                                         FALSE,
+                                                         GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY));
+
   gtk_widget_class_install_style_property (widget_class,
 					   g_param_spec_int ("handle-size",
 							     P_("Handle Size"),
@@ -852,6 +870,9 @@ gtk_paned_set_property (GObject        *object,
           g_object_notify_by_pspec (object, pspec);
         }
       break;
+    case PROP_WIDE_HANDLE:
+      gtk_paned_set_wide_handle (paned, g_value_get_boolean (value));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -884,6 +905,9 @@ gtk_paned_get_property (GObject        *object,
     case PROP_MAX_POSITION:
       g_value_set_int (value, priv->max_position);
       break;
+    case PROP_WIDE_HANDLE:
+      g_value_set_boolean (value, gtk_paned_get_wide_handle (paned));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -2842,3 +2866,59 @@ gtk_paned_get_handle_window (GtkPaned *paned)
 
   return paned->priv->handle;
 }
+
+/**
+ * gtk_paned_set_wide_handle:
+ * @paned: a #GtkPaned
+ * @wide: the new value for the #GtkPaned:wide-handle property
+ *
+ * Sets the #GtkPaned:wide-handle property.
+ *
+ * Since: 3.16
+ */
+void
+gtk_paned_set_wide_handle (GtkPaned *paned,
+                           gboolean  wide)
+{
+  GtkStyleContext *context;
+  gboolean old_wide;
+
+  g_return_if_fail (GTK_IS_PANED (paned));
+
+  old_wide = gtk_paned_get_wide_handle (paned);
+  if (old_wide != wide)
+    {
+      context = gtk_widget_get_style_context (GTK_WIDGET (paned));
+      if (wide)
+        gtk_style_context_add_class (context, GTK_STYLE_CLASS_WIDE);
+      else
+        gtk_style_context_remove_class (context, GTK_STYLE_CLASS_WIDE);
+
+      gtk_widget_queue_resize (GTK_WIDGET (paned));
+      g_object_notify (G_OBJECT (paned), "wide-handle");
+    }
+}
+
+/**
+ * gtk_paned_get_wide_handle:
+ * @paned: a #GtkPaned
+ *
+ * Gets the #GtkPaned:wide-handle property.
+ *
+ * Returns: %TRUE if the paned should have a wide handle
+ *
+ * Since: 3.16
+ */
+gboolean
+gtk_paned_get_wide_handle (GtkPaned *paned)
+{
+  GtkStyleContext *context;
+
+  g_return_val_if_fail (GTK_IS_PANED (paned), FALSE);
+  
+  context = gtk_widget_get_style_context (GTK_WIDGET (paned));
+  if (gtk_style_context_has_class (context, GTK_STYLE_CLASS_WIDE))
+    return TRUE;
+  else
+    return FALSE;
+}

gtk/gtkpaned.h

@@ -110,6 +110,12 @@ GtkWidget * gtk_paned_get_child2   (GtkPaned       *paned);
 GDK_AVAILABLE_IN_ALL
 GdkWindow * gtk_paned_get_handle_window (GtkPaned  *paned);
 
+GDK_AVAILABLE_IN_3_16
+void        gtk_paned_set_wide_handle (GtkPaned    *paned,
+                                       gboolean     wide);
+GDK_AVAILABLE_IN_3_16
+gboolean    gtk_paned_get_wide_handle (GtkPaned    *paned);
+
 
 G_END_DECLS
 

gtk/gtkstylecontext.h

@@ -915,6 +915,16 @@ struct _GtkStyleContextClass
  */
 #define GTK_STYLE_CLASS_MONOSPACE "monospace"
 
+/**
+ * GTK_STYLE_CLASS_WIDE:
+ *
+ * A CSS class to indicate that a UI element should be 'wide'.
+ * Used by #GtkPaned.
+ *
+ * Since: 3.16
+ */
+#define GTK_STYLE_CLASS_WIDE "wide"
+
 /**
  * GTK_STYLE_REGION_ROW:
  *