Index: trunk/src/obj_poly.c
===================================================================
--- trunk/src/obj_poly.c	(revision 10047)
+++ trunk/src/obj_poly.c	(revision 10048)
@@ -783,7 +783,32 @@
 }
 
 
+/*** iteration helpers ***/
+void pcb_poly_map_contours(pcb_polygon_t *p, void *ctx, pcb_poly_map_cb_t *cb)
+{
+	pcb_polyarea_t *pa;
+	pcb_pline_t *pl;
 
+	pa = p->Clipped;
+	do {
+		int cidx;
+		for(cidx = 0, pl = pa->contours; pl != NULL; cidx++, pl = pl->next) {
+			pcb_vnode_t *v;
+			cb(p, ctx, (cidx == 0 ? PCB_POLYEV_ISLAND_START : PCB_POLYEV_HOLE_START), 0, 0);
+			v = pa->contours->head.next;
+			do {
+				cb(p, ctx, (cidx == 0 ? PCB_POLYEV_ISLAND_POINT : PCB_POLYEV_HOLE_POINT), v->point[0], v->point[1]);
+			} while ((v = v->next) != pa->contours->head.next);
+
+			cb(p, ctx, (cidx == 0 ? PCB_POLYEV_ISLAND_END : PCB_POLYEV_HOLE_END), 0, 0);
+		}
+		pa = pa->f;
+	} while(pa != p->Clipped);
+}
+
+
+
+
 /*** draw ***/
 pcb_r_dir_t draw_poly_callback(const pcb_box_t * b, void *cl)
 {
Index: trunk/src/obj_poly.h
===================================================================
--- trunk/src/obj_poly.h	(revision 10047)
+++ trunk/src/obj_poly.h	(revision 10048)
@@ -76,6 +76,27 @@
 
 double pcb_poly_area(const pcb_polygon_t *poly);
 
+/*** helpers for iterating over countours */
+
+/*** Polygon helpers on the clopped polygon ***/
+typedef enum {
+	PCB_POLYEV_ISLAND_START,
+	PCB_POLYEV_ISLAND_POINT,
+	PCB_POLYEV_ISLAND_END,
+	PCB_POLYEV_HOLE_START,
+	PCB_POLYEV_HOLE_POINT,
+	PCB_POLYEV_HOLE_END
+} pcb_poly_event_t;
+
+/* return non-zero to quit mapping immediatley */
+typedef int pcb_poly_map_cb_t(pcb_polygon_t *p, void *ctx, pcb_poly_event_t ev, pcb_coord_t x, pcb_coord_t y);
+
+/* call cb for each point of each island and cutout */
+void pcb_poly_map_contours(pcb_polygon_t *p, void *ctx, pcb_poly_map_cb_t *cb);
+
+
+/*** loops ***/
+
 #define PCB_POLY_LOOP(layer) do {                                    \
   pcb_polygon_t *polygon;                                             \
   gdl_iterator_t __it__;                                            \