Index: trunk/src/data.c
===================================================================
--- trunk/src/data.c	(revision 13022)
+++ trunk/src/data.c	(revision 13023)
@@ -557,6 +557,15 @@
 	} PCB_ENDALL_LOOP;
 }
 
+void pcb_data_clip_polys(pcb_data_t *data)
+{
+	PCB_POLY_ALL_LOOP(data);
+	{
+		pcb_poly_init_clip(data, layer, polygon);
+	}
+	PCB_ENDALL_LOOP;
+}
+
 #define rsearch(tree) \
 	do { \
 		pcb_r_dir_t tmp = pcb_r_search(tree, starting_region, region_in_search, rectangle_in_region, closure, num_found); \
Index: trunk/src/data.h
===================================================================
--- trunk/src/data.h	(revision 13022)
+++ trunk/src/data.h	(revision 13023)
@@ -157,6 +157,10 @@
 
 void pcb_data_move(pcb_data_t *data, pcb_coord_t dx, pcb_coord_t dy);
 
+/* run pcb_poly_init_clip() on all polygons in data */
+void pcb_data_clip_polys(pcb_data_t *data);
+
+
 /* rsearch on all trees matching types of data */
 pcb_r_dir_t pcb_data_r_search(pcb_data_t *data, pcb_objtype_t types, const pcb_box_t *starting_region,
 						 pcb_r_dir_t (*region_in_search) (const pcb_box_t *region, void *cl),