[gtkparasite] window: Add a "Follow" button

[Benjamin Otte <otte src gnome org>]

commit d20c5d205e981fe06542ccf59273ef069a2c9992
Author: Benjamin Otte <otte redhat com>
Date:   Fri Mar 15 20:24:08 2013 +0100

    window: Add a "Follow" button
    
    This will make the displayed widget follow the mouse pointer, so one can
    leave the gtkparasite window in the background and see what's happening
    below the mouse pointer.
    
    I use it to debug menus.

 src/parasite.h |    1 +
 src/window.c   |   62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 62 insertions(+), 1 deletions(-)
---
diff --git a/src/parasite.h b/src/parasite.h
index 906e7b4..90a1899 100644
--- a/src/parasite.h
+++ b/src/parasite.h
@@ -55,6 +55,7 @@ typedef struct
     GtkWidget *widget_path_entry;
     GtkWidget *style_classes_entry;
     guint style_classes_entry_ratelimit_id;
+    guint follow_id;
 } ParasiteWindow;
 
 
diff --git a/src/window.c b/src/window.c
index dd4f2e2..25701e3 100644
--- a/src/window.c
+++ b/src/window.c
@@ -48,7 +48,8 @@ on_widget_tree_selection_changed(ParasiteWidgetTree *widget_tree,
         g_free (path);
 
         /* Flash the widget. */
-        gtkparasite_flash_widget(parasite, selected);
+        if (!parasite->follow_id)
+          gtkparasite_flash_widget(parasite, selected);
     }
     else
     {
@@ -200,6 +201,58 @@ on_edit_mode_toggled(GtkWidget *toggle_button,
                                        active);
 }
 
+static gboolean
+on_follow_timeout (gpointer data)
+{
+  ParasiteWindow *parasite = data;
+  GdkDevice *device;
+  GdkWindow *window;
+
+  device = gdk_device_manager_get_client_pointer (gdk_display_get_device_manager (gtk_widget_get_display 
(parasite->window)));
+  window = gdk_device_get_window_at_position (device, NULL, NULL);
+
+  if (window != NULL &&
+      gdk_window_get_toplevel (window) != gtk_widget_get_window (parasite->window))
+  {
+    GtkWidget *toplevel = NULL;
+    GtkWidget *widget = NULL;
+
+    gdk_window_get_user_data(gdk_window_get_toplevel(window), (gpointer*)&toplevel);
+    gdk_window_get_user_data(window, (gpointer*)&widget);
+
+    if (toplevel)
+    {
+        parasite_widget_tree_scan(PARASITE_WIDGET_TREE(parasite->widget_tree),
+                                  toplevel);
+    }
+
+    if (widget)
+    {
+        parasite_widget_tree_select_widget(PARASITE_WIDGET_TREE(parasite->widget_tree),
+                                           widget);
+    }
+  }
+
+  return TRUE;
+}
+
+static void
+on_follow_toggled(GtkWidget *toggle_button,
+                  ParasiteWindow *parasite)
+{
+  if (gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(toggle_button)))
+  {
+    parasite->follow_id = g_timeout_add_seconds (1,
+                                                 on_follow_timeout,
+                                                 parasite);
+  }
+  else
+  {
+    g_source_remove (parasite->follow_id);
+    parasite->follow_id = 0;
+  }
+}
+
 static void
 on_show_graphic_updates_toggled(GtkWidget *toggle_button,
                                 ParasiteWindow *parasite)
@@ -236,6 +289,13 @@ create_widget_tree(ParasiteWindow *parasite)
     gtk_widget_show(button);
     gtk_box_pack_start(GTK_BOX(bbox), button, FALSE, FALSE, 0);
 
+    button = gtk_toggle_button_new_with_mnemonic("_Follow");
+    gtk_widget_show(button);
+    gtk_box_pack_start(GTK_BOX(bbox), button, FALSE, FALSE, 0);
+
+    g_signal_connect(G_OBJECT(button), "toggled",
+                     G_CALLBACK(on_follow_toggled), parasite);
+
     button = gtk_toggle_button_new_with_mnemonic("_Edit Mode");
     gtk_widget_show(button);
     gtk_box_pack_start(GTK_BOX(bbox), button, FALSE, FALSE, 0);