From e49434ec6c7799a51c192d4d13def636b51f6665 Mon Sep 17 00:00:00 2001
From: Adam Wulkiewicz <adam.wulkiewicz@gmail.com>
Date: Tue, 8 Jul 2014 21:16:18 +0200
Subject: [PATCH] [strategies] Add less-comparator for projected_point_ax
 result in detail::douglas_peucker

---
 .../cartesian/distance_projected_point_ax.hpp | 21 ++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/include/boost/geometry/strategies/cartesian/distance_projected_point_ax.hpp b/include/boost/geometry/strategies/cartesian/distance_projected_point_ax.hpp
index a149097dd..ace642f7c 100644
--- a/include/boost/geometry/strategies/cartesian/distance_projected_point_ax.hpp
+++ b/include/boost/geometry/strategies/cartesian/distance_projected_point_ax.hpp
@@ -67,12 +67,27 @@ struct projected_point_ax_result
     {}
 
     T atd, xtd;
+};
 
-    friend bool operator>(projected_point_ax_result const& left,
-                          projected_point_ax_result const& right)
+// This less-comparator may be used as a parameter of detail::douglas_peucker.
+// In this simplify strategy distances are compared in 2 places
+// 1. to choose the furthest candidate (md < dist)
+// 2. to check if the candidate is further than max_distance (max_distance < md)
+template <typename Distance>
+class projected_point_ax_less
+{
+public:
+    projected_point_ax_less(Distance const& max_distance)
+        : m_max_distance(max_distance)
+    {}
+
+    template <typename T>
+    inline bool operator()(Distance const& left, Distance const& right) const
     {
-        return left.atd > right.atd || left.xtd > right.xtd;
+        return left.xtd < right.xtd && right.atd < m_max_distance.atd;
     }
+private:
+    Distance const& m_max_distance;
 };
 
 // This strategy returns 2-component Point/Segment distance.