Index: trunk/src/obj_common.c
===================================================================
--- trunk/src/obj_common.c	(revision 10942)
+++ trunk/src/obj_common.c	(revision 10943)
@@ -135,12 +135,12 @@
 	pcb_attribute_copy_all(&o->Attributes, src);
 }
 
-void pcb_obj_center(pcb_any_obj_t *obj, pcb_coord_t *x, pcb_coord_t *y)
+void pcb_obj_center(const pcb_any_obj_t *obj, pcb_coord_t *x, pcb_coord_t *y)
 {
 	switch (obj->type) {
 		case PCB_OBJ_PIN:
-			*x = ((pcb_pin_t *)(obj))->X;
-			*y = ((pcb_pin_t *)(obj))->Y;
+			*x = ((const pcb_pin_t *)(obj))->X;
+			*y = ((const pcb_pin_t *)(obj))->Y;
 			break;
 		case PCB_OBJ_ARC:
 			pcb_arc_middle((const pcb_arc_t *)obj, x, y);
Index: trunk/src/obj_common.h
===================================================================
--- trunk/src/obj_common.h	(revision 10942)
+++ trunk/src/obj_common.h	(revision 10943)
@@ -158,7 +158,7 @@
 
 /* Return the geometric center of an object, as shown (center of bbox usually,
    but not for an arc) */
-void pcb_obj_center(pcb_any_obj_t *obj, pcb_coord_t *x, pcb_coord_t *y);
+void pcb_obj_center(const pcb_any_obj_t *obj, pcb_coord_t *x, pcb_coord_t *y);
 
 /* Update cached attributes (->term) */
 void pcb_obj_attrib_post_change(pcb_attribute_list_t *list, const char *name, const char *value);