+ VikDataSourceOffFunc off_func;
+
+ /*** UI Building ***/
+ VikLayerParam * params;
+ guint16 params_count;
+ VikLayerParamData * params_defaults;
+ gchar ** params_groups;
+ guint8 params_groups_count;
+
+};
+
+/**********************************/
+/**********************************/
+/**********************************/
+
+/* for sources with no input data */
+void a_acquire ( VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp, VikDataSourceInterface *source_interface );
+
+/* Create a sub menu intended for rightclicking on a TRWLayer. menu called "Filter"
+ * returns NULL if no filters */
+GtkWidget *a_acquire_trwlayer_menu (VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp, VikTrwLayer *vtl);
+
+/* Create a sub menu intended for rightclicking on a TRWLayer. menu called "Filter with Track "TRACKNAME"..."
+ * returns NULL if no filters or no filter track has been set
+ */
+GtkWidget *a_acquire_trwlayer_track_menu (VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp, VikTrwLayer *vtl);
+
+/* Create a sub menu intended for rightclicking on a track. menu called "Filter"
+ * returns NULL if no applicable filters */
+GtkWidget *a_acquire_track_menu (VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp, VikTrack *tr);