cameo/: new commands "remove" and "keep" for path filtering (untested)

cameo/ops.c

@@ -153,3 +153,41 @@ struct path *reverse_paths(const struct path *paths)
 	}
 	return res;
 }
+
+
+static int select_path(const struct path *path, double xa, double ya,
+    double xb, double yb, int inside)
+{
+	const struct point *p;
+
+	for (p = path->first; p; p = p->next) {
+		if (p->x >= xa && p->x <= xb && p->y >= ya && p->y <= yb) {
+			if (!inside)
+				return 0;
+		} else {
+			if (inside)
+				return 0;
+		}
+	}
+	return 1;
+}
+
+
+struct path *select_paths(const struct path *paths, double xa, double ya,
+    double xb, double yb, int inside)
+{
+	struct path *res = NULL, **last = &res;
+
+	if (xa > xb)
+		return select_paths(paths, xb, ya, xa, yb, inside);
+	if (ya > yb)
+		return select_paths(paths, xa, yb, xb, ya, inside);
+	while (paths) {
+		if (select_path(paths, xa, ya, xb, yb, inside)) {
+			*last = path_clone(paths);
+			last = &(*last)->next;
+		}
+		paths = paths->next;
+	}
+	return res;
+}