[eog] EogWindow: Fix feedback loop from zoom scale to scroll view

[Felix Riemann <friemann src gnome org>]

commit e52a64c4180c2245d1c484aa1b88fa2d5c9803b8
Author: Felix Riemann <friemann gnome org>
Date:   Fri Apr 10 21:44:28 2015 +0200

    EogWindow: Fix feedback loop from zoom scale to scroll view
    
    Block signal handler to avoid setting the zoom again when the
    scroll view sets the zoom on its own. Although the scroll view
    will usually ignore these resets it won't do so if the zoom scale
    clamps the zoom factor to its own allowed range.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=747410

 src/eog-window.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)
---
diff --git a/src/eog-window.c b/src/eog-window.c
index a309788..58b9de0 100644
--- a/src/eog-window.c
+++ b/src/eog-window.c
@@ -204,6 +204,8 @@ static void eog_window_list_store_image_removed (GtkTreeModel *tree_model,
 static void eog_window_set_wallpaper (EogWindow *window, const gchar *filename, const gchar 
*visible_filename);
 static gboolean eog_window_save_images (EogWindow *window, GList *images);
 static void eog_window_finish_saving (EogWindow *window);
+static void eog_window_zoom_scale_value_changed_cb (GtkRange *range,
+                                                   gpointer user_data);
 
 static GQuark
 eog_window_error_quark (void)
@@ -1573,7 +1575,19 @@ view_zoom_changed_cb (GtkWidget *widget, double zoom, gpointer user_data)
        window = EOG_WINDOW (user_data);
 
        update_status_bar (window);
+
+       /* Block signal handler to avoid setting the zoom again.
+        * Although the ScrollView will usually ignore it, it won't
+        * do so when the zoom scale clamps the zoom factor to its
+        * own allowed range. (#747410)
+        */
+       g_signal_handlers_block_by_func (window->priv->zoom_scale,
+                                        eog_window_zoom_scale_value_changed_cb,
+                                        window);
        update_zoom_scale (window);
+       g_signal_handlers_unblock_by_func (window->priv->zoom_scale,
+                                          eog_window_zoom_scale_value_changed_cb,
+                                          window);
 
        action_zoom_in =
                g_action_map_lookup_action (G_ACTION_MAP (window),