From 6eb9e238bcb37e26dc31d16acf826784a2ba30f4 Mon Sep 17 00:00:00 2001
From: Adam Wulkiewicz <adam.wulkiewicz@gmail.com>
Date: Thu, 11 Mar 2021 00:45:08 +0100
Subject: [PATCH] [strategies] Remove distance() dependency from
 weighted_length strategy.

Also add optional CalculationType.
---
 .../cartesian/centroid_weighted_length.hpp    | 31 +++++++++++--------
 .../strategies/centroid/cartesian.hpp         |  2 +-
 test/cs_undefined/index.cpp                   |  3 +-
 3 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/include/boost/geometry/strategies/cartesian/centroid_weighted_length.hpp b/include/boost/geometry/strategies/cartesian/centroid_weighted_length.hpp
index bb7dea775..115956fa3 100644
--- a/include/boost/geometry/strategies/cartesian/centroid_weighted_length.hpp
+++ b/include/boost/geometry/strategies/cartesian/centroid_weighted_length.hpp
@@ -21,17 +21,17 @@
 #include <boost/math/special_functions/fpclassify.hpp>
 #include <boost/numeric/conversion/cast.hpp>
 
-#include <boost/geometry/algorithms/detail/distance/interface.hpp>
-#include <boost/geometry/algorithms/detail/distance/point_to_geometry.hpp>
 #include <boost/geometry/arithmetic/arithmetic.hpp>
-#include <boost/geometry/util/for_each_coordinate.hpp>
-#include <boost/geometry/util/select_most_precise.hpp>
-#include <boost/geometry/strategies/centroid.hpp>
-#include <boost/geometry/strategies/default_distance_result.hpp>
 
 // Helper geometry
 #include <boost/geometry/geometries/point.hpp>
 
+#include <boost/geometry/strategies/cartesian/distance_pythagoras.hpp>
+#include <boost/geometry/strategies/centroid.hpp>
+
+#include <boost/geometry/util/for_each_coordinate.hpp>
+#include <boost/geometry/util/select_most_precise.hpp>
+
 
 namespace boost { namespace geometry
 {
@@ -42,19 +42,24 @@ namespace strategy { namespace centroid
 template
 <
     typename Ignored1 = void,
-    typename Ignored2 = void
+    typename Ignored2 = void,
+    typename CalculationType = void
 >
 class weighted_length
 {
 private :
+    typedef geometry::strategy::distance::pythagoras<CalculationType> pythagoras_strategy;
+
     template <typename GeometryPoint, typename ResultPoint>
     struct calculation_type
-        : select_most_precise
+    {
+        // Below the distance between two GeometryPoints is calculated.
+        // ResultPoint is taken into account by passing them together here.
+        typedef typename pythagoras_strategy::template calculation_type
             <
-                typename default_distance_result<GeometryPoint>::type,
-                typename default_distance_result<ResultPoint>::type
-            >
-    {};
+                GeometryPoint, ResultPoint
+            >::type type;
+    };
 
     template <typename GeometryPoint, typename ResultPoint>
     class sums
@@ -94,7 +99,7 @@ public :
     {
         typedef typename calculation_type<GeometryPoint, ResultPoint>::type distance_type;
 
-        distance_type const d = geometry::distance(p1, p2);
+        distance_type const d = pythagoras_strategy::apply(p1, p2);
         state.length += d;
 
         typename sums<GeometryPoint, ResultPoint>::work_point weighted_median;
diff --git a/include/boost/geometry/strategies/centroid/cartesian.hpp b/include/boost/geometry/strategies/centroid/cartesian.hpp
index 6870919a7..14b45155a 100644
--- a/include/boost/geometry/strategies/centroid/cartesian.hpp
+++ b/include/boost/geometry/strategies/centroid/cartesian.hpp
@@ -48,7 +48,7 @@ struct cartesian
                                 util::is_polylinear<Geometry>::value
                             > * = nullptr)
     {
-        return strategy::centroid::weighted_length<>();
+        return strategy::centroid::weighted_length<void, void, CalculationType>();
     }
 
     template <typename Geometry>
diff --git a/test/cs_undefined/index.cpp b/test/cs_undefined/index.cpp
index 5908aa248..4a3ef8676 100644
--- a/test/cs_undefined/index.cpp
+++ b/test/cs_undefined/index.cpp
@@ -1,6 +1,6 @@
 // Boost.Geometry
 
-// Copyright (c) 2019-2020, Oracle and/or its affiliates.
+// Copyright (c) 2019-2021, Oracle and/or its affiliates.
 
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
@@ -11,6 +11,7 @@
 
 // These includes are required for the following code to compile.
 // This is probably wrong.
+#include <boost/geometry/algorithms/comparable_distance.hpp>
 #include <boost/geometry/algorithms/covered_by.hpp>
 #include <boost/geometry/algorithms/disjoint.hpp>
 #include <boost/geometry/algorithms/equals.hpp>