cameo/: move conversion between poly2d and "struct path" from area-poly2d.c to poly2d.c

Untested.

cameo/poly2d.c

@@ -0,0 +1,90 @@
+/*
+ * poly2d.c - Poly2D interface functions
+ *
+ * Written 2012 by Werner Almesberger
+ * Copyright 2012 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#include <math.h>
+#include <assert.h>
+
+#include "path.h"
+#include "poly2d.h"
+
+
+struct p2d *path_to_poly(const struct path *path)
+{
+	struct p2d *poly;
+	const struct point *p;
+
+	if (!path->first || !path->first->next)
+		return NULL;
+
+	poly = p2d_new();
+	for (p = path->first; p && p->next; p = p->next)
+		p2d_append(poly, v2d_new(p->x, p->y));
+	if (path_is_closed(path))
+		p2d_close(poly);
+	return poly;
+}
+
+
+struct p2d *paths_to_polys_z(const struct path *paths, 
+    double zmin, double zmax)
+{
+	struct p2d *polys = NULL, **last = &polys;
+	const struct path *path;
+
+	assert(zmin <= zmax);
+	for (path = paths; path; path = path->next) {
+		if (path->first->z < zmin || path->first->z > zmax)
+			continue;
+		*last = path_to_poly(path);
+		last = &(*last)->next;
+	}
+	return polys;
+}
+
+
+struct p2d *paths_to_polys(const struct path *paths)
+{
+	return paths_to_polys_z(paths, -HUGE_VAL, HUGE_VAL);
+}
+
+
+struct path *poly_to_path(const struct p2d *poly, double r_tool, double z)
+{
+	struct path *path;
+	const struct v2d *v;
+
+	path = path_new(r_tool, "");
+	v = poly->v;
+	while (v) {
+		path_add(path, v->x, v->y, z);
+		v = v->next;
+		if (v == poly->v)
+			break;
+	}
+	if (v)
+		path_add(path, v->x, v->y, z);
+	return path;
+}
+
+
+struct path *polys_to_paths(const struct p2d *polys, double r_tool, double z)
+{
+	struct path *paths = NULL, **last = &paths;
+	const struct p2d *poly;
+
+	for (poly = polys; poly; poly = poly->next) {
+		*last = poly_to_path(poly, r_tool, z);
+		last = &(*last)->next;
+	}
+	return paths;
+}