comment about theory and origins of trapezoid.c

diff --git a/lib/ortho/trapezoid.c b/lib/ortho/trapezoid.c
index 21638dce6868b55b287eb7ff0092370ae8ae35f0..31c19f02258442d46dbebcca1faf58e97e1ff126 100644 (file)
--- a/lib/ortho/trapezoid.c
+++ b/lib/ortho/trapezoid.c
@@ -1,3 +1,11 @@
+/**
+ * @file
+ * @brief trapezoidation
+ *
+ * See [Fast polygon triangulation based on Seidel's algorithm](http://gamma.cs.unc.edu/SEIDEL/)
+ *
+ */
+
 /*************************************************************************
  * Copyright (c) 2011 AT&T Intellectual Property
  * All rights reserved. This program and the accompanying materials