[gthumb] browser: added support for back and forward mouse buttons

[Paolo Bacchilega <paobac src gnome org>]

commit 1578e069676d615ccf87c7a75eecaf00684abd28
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Nov 29 14:44:10 2020 +0100

    browser: added support for back and forward mouse buttons
    
    Fixes https://gitlab.gnome.org/GNOME/gthumb/-/issues/120

 gthumb/gth-browser.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 gthumb/gth-window.c  | 14 ++++++++++++++
 gthumb/gth-window.h  |  3 +++
 3 files changed, 68 insertions(+)
---
diff --git a/gthumb/gth-browser.c b/gthumb/gth-browser.c
index 0e4af4f2..81034e49 100644
--- a/gthumb/gth-browser.c
+++ b/gthumb/gth-browser.c
@@ -134,6 +134,7 @@ struct _GthBrowserPrivate {
        GtkWidget         *progress_dialog;
 
        GHashTable        *named_dialogs;
+       GtkGesture        *gesture;
 
        /* Browser data */
 
@@ -2589,6 +2590,7 @@ gth_browser_finalize (GObject *object)
        _g_object_list_unref (browser->priv->history);
        gth_icon_cache_free (browser->priv->menu_icon_cache);
        g_hash_table_unref (browser->priv->named_dialogs);
+       g_object_unref (browser->priv->gesture);
        g_free (browser->priv->list_attributes);
        _g_object_unref (browser->priv->folder_popup_file_data);
        _g_object_unref (browser->priv->history_menu);
@@ -4199,6 +4201,47 @@ _gth_browser_register_fixed_viewer_control (GthBrowser *browser,
 }
 
 
+static void
+browser_gesture_pressed_cb (GtkGestureMultiPress *gesture,
+                           int                   n_press,
+                           double                x,
+                           double                y,
+                           gpointer              user_data)
+{
+       GthBrowser *browser = user_data;
+       guint       button;
+
+       button = gtk_gesture_single_get_current_button (GTK_GESTURE_SINGLE (gesture));
+       switch (button) {
+       case 8: /* Back button */
+               switch (gth_window_get_current_page (GTH_WINDOW (browser))) {
+               case GTH_BROWSER_PAGE_VIEWER:
+                       gth_window_activate_action (GTH_WINDOW (browser), "browser-mode", NULL);
+                       break;
+               case GTH_BROWSER_PAGE_BROWSER:
+                       gth_browser_go_back (browser, 1);
+                       break;
+               default:
+                       break;
+               }
+               break;
+
+       case 9: /* Forward button */
+               switch (gth_window_get_current_page (GTH_WINDOW (browser))) {
+               case GTH_BROWSER_PAGE_BROWSER:
+                       gth_browser_go_forward (browser, 1);
+                       break;
+               default:
+                       break;
+               }
+               break;
+
+       default:
+               break;
+       }
+}
+
+
 static gboolean
 browser_key_press_cb (GthBrowser  *browser,
                      GdkEventKey *event)
@@ -4357,6 +4400,14 @@ gth_browser_init (GthBrowser *browser)
                          G_CALLBACK (browser_key_press_cb),
                          browser);
 
+       browser->priv->gesture = gtk_gesture_multi_press_new (GTK_WIDGET (browser));
+       gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (browser->priv->gesture), 0);
+       gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (browser->priv->gesture), 
GTK_PHASE_CAPTURE);
+       g_signal_connect (browser->priv->gesture,
+                         "pressed",
+                         G_CALLBACK (browser_gesture_pressed_cb),
+                         browser);
+
        /* ui actions */
 
        g_action_map_add_action_entries (G_ACTION_MAP (browser),
diff --git a/gthumb/gth-window.c b/gthumb/gth-window.c
index ac82e167..e1352e91 100644
--- a/gthumb/gth-window.c
+++ b/gthumb/gth-window.c
@@ -807,6 +807,20 @@ gth_window_change_action_state (GthWindow  *window,
 }
 
 
+void
+gth_window_activate_action (GthWindow  *window,
+                           const char  *action_name,
+                           GVariant    *parameter)
+{
+       GAction *action;
+
+       action = g_action_map_lookup_action (G_ACTION_MAP (window), action_name);
+       g_return_if_fail (action != NULL);
+
+       g_action_activate (action, parameter);
+}
+
+
 void
 gth_window_add_viewer_shortcuts (GthWindow         *window,
                                 const char        *viewer_context,
diff --git a/gthumb/gth-window.h b/gthumb/gth-window.h
index f152e2e2..99e2ffa6 100644
--- a/gthumb/gth-window.h
+++ b/gthumb/gth-window.h
@@ -121,6 +121,9 @@ gboolean    gth_window_get_action_state     (GthWindow              *window,
 void           gth_window_change_action_state  (GthWindow              *window,
                                                 const char             *action_name,
                                                 gboolean                value);
+void           gth_window_activate_action      (GthWindow              *window,
+                                                const char             *action_name,
+                                                GVariant               *parameter);
 void           gth_window_add_viewer_shortcuts (GthWindow              *window,
                                                 const char             *viewer_context,
                                                 const GthShortcut      *shortcuts,