Add arc len computation method to point

[hubacji1/iamcar2.git] / bcar / incl / bcar.hh

diff --git a/bcar/incl/bcar.hh b/bcar/incl/bcar.hh
index 3afde08906b74aebc75014d7bc5ab3b080a99181..ebe655724287e9e5963eaf9df749f84ae56491e1 100644 (file)
--- a/bcar/incl/bcar.hh
+++ b/bcar/incl/bcar.hh
@@ -92,6 +92,12 @@ public:
        /*! Return Euclidean distance to `p`. */
        double edist(Point const& p) const;
 
+       /*! Return length of arc between two points when radius is kwown.
+        *
+        * \see https://math.stackexchange.com/questions/1595872/arclength-between-two-points-on-a-circle-not-knowing-theta
+        */
+       double arc_len(Point const& p, double r);
+
        /*! Generate output for plotting with gnuplot. */
        void gen_gnuplot_to(std::ostream& out);