views: add time direction property

The time direction property tells which orientation one
needs to scroll to change the time of the view. In these
directions (up/down v left/right) the new prev/next
buttons will be pointing.

The two buttons will be added in a subsequent commit,
and will gain view-dependent tooltips.

Signed-off-by: Markus Göllnitz <camelcasenick@bewares.it>
Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/542>

src/gui/views/gcal-month-view.c

@@ -96,6 +96,7 @@ enum
   PROP_0,
   PROP_CONTEXT,
   PROP_DATE,
+  PROP_TIME_DIRECTION,
   N_PROPS,
 };
 
@@ -1592,6 +1593,10 @@ gcal_month_view_get_property (GObject    *object,
       g_value_set_object (value, self->context);
       break;
 
+    case PROP_TIME_DIRECTION:
+      g_value_set_enum (value, GTK_ORIENTATION_VERTICAL);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
@@ -1644,6 +1649,7 @@ gcal_month_view_class_init (GcalMonthViewClass *klass)
 
   g_object_class_override_property (object_class, PROP_CONTEXT, "context");
   g_object_class_override_property (object_class, PROP_DATE, "active-date");
+  g_object_class_override_property (object_class, PROP_TIME_DIRECTION, "time-direction");
 
   gtk_widget_class_set_template_from_resource (widget_class, "/org/gnome/calendar/ui/views/gcal-month-view.ui");