fix: add condition to handle_imperfect_touch

doc/release_notes.qbk

@@ -43,6 +43,7 @@
 * [@https://github.com/boostorg/geometry/issues/1226 1226] [@https://github.com/boostorg/geometry/issues/1326 1326] Fix extra round on ring
 * [@https://github.com/boostorg/geometry/issues/1293 1293] [@https://github.com/boostorg/geometry/issues/1294 1294] [@https://github.com/boostorg/geometry/issues/1295 1295] Fix traversal through non clustered rings
 * [@https://github.com/boostorg/geometry/issues/1342 1342] Fix discarding a start turn for combination with touch
+* [@https://github.com/boostorg/geometry/issues/1345 1345] Fix in handling imperfect touch
 
 [/=================]
 [heading Boost 1.85]

include/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp

@@ -569,7 +569,7 @@ struct touch : public base_turn_handler
             // ||
             // |^----
             // >----->P
-            // *            * they touch here (P/Q are (nearly) on top)
+            // *            * they touch here (P/Q are (nearly) on top of each other)
             //
             // Q continues from where P comes.
             // P continues from where Q comes
@@ -586,6 +586,14 @@ struct touch : public base_turn_handler
             // >----->P     qj is LEFT of P1 and pi is LEFT of Q2
             //              (the other way round is also possible)
 
+            // There are also cases like this:
+            //      P
+            //      ^
+            //      ||
+            //      ||
+            // P----^-----<Q
+            // This code is not for these cases because of the condition opposite(side.pi_wrt_q1(), side.qk_wrt_p2())
+
             auto has_distance = [&](auto const& r1, auto const& r2) -> bool
             {
                 auto const d1 = get_distance_measure(r1.at(0), r1.at(1), r2.at(1), umbrella_strategy);
@@ -674,6 +682,7 @@ struct touch : public base_turn_handler
             {
                 if (side_qk_p1 == 0 && side_pk_q1 == 0
                     && has_pk && has_qk
+                    && opposite(side.pi_wrt_q1(), side.qk_wrt_p2())
                     && handle_imperfect_touch(range_p, range_q, side_pk_q2, umbrella_strategy, ti))
                 {
                     // If q continues collinearly (opposite) with p, it should be blocked

include/boost/geometry/algorithms/detail/overlay/get_turn_info_helpers.hpp

@@ -58,6 +58,13 @@ struct side_calculator
         , m_range_q(range_q)
     {}
 
+    inline int pi_wrt_q1() const { return m_side_strategy.apply(get_qi(), get_qj(), get_pi()); }
+
+    inline int pj_wrt_q1() const { return m_side_strategy.apply(get_qi(), get_qj(), get_pj()); }
+    inline int pj_wrt_q2() const { return m_side_strategy.apply(get_qj(), get_qk(), get_pj()); }
+    inline int qj_wrt_p1() const { return m_side_strategy.apply(get_pi(), get_pj(), get_qj()); }
+    inline int qj_wrt_p2() const { return m_side_strategy.apply(get_pj(), get_pk(), get_qj()); }
+
     inline int pk_wrt_p1() const { return m_side_strategy.apply(get_pi(), get_pj(), get_pk()); }
     inline int pk_wrt_q1() const { return m_side_strategy.apply(get_qi(), get_qj(), get_pk()); }
     inline int qk_wrt_p1() const { return m_side_strategy.apply(get_pi(), get_pj(), get_qk()); }
@@ -66,12 +73,6 @@ struct side_calculator
     inline int pk_wrt_q2() const { return m_side_strategy.apply(get_qj(), get_qk(), get_pk()); }
     inline int qk_wrt_p2() const { return m_side_strategy.apply(get_pj(), get_pk(), get_qk()); }
 
-    // Necessary when rescaling turns off:
-    inline int qj_wrt_p1() const { return m_side_strategy.apply(get_pi(), get_pj(), get_qj()); }
-    inline int qj_wrt_p2() const { return m_side_strategy.apply(get_pj(), get_pk(), get_qj()); }
-    inline int pj_wrt_q1() const { return m_side_strategy.apply(get_qi(), get_qj(), get_pj()); }
-    inline int pj_wrt_q2() const { return m_side_strategy.apply(get_qj(), get_qk(), get_pj()); }
-
     inline auto const& get_pi() const { return m_range_p.at(0); }
     inline auto const& get_pj() const { return m_range_p.at(1); }
     inline auto const& get_pk() const { return m_range_p.at(2); }

test/algorithms/overlay/overlay_cases.hpp

@@ -1231,6 +1231,59 @@ static std::string issue_1342_b[2] =
     "POLYGON((2.000000861538488 2.944711629068049e-16,2.000000861538488 2.0000008,23.52786548447633 2.0000008,23.52786548447633 2.944711629068049e-16,2.000000861538488 2.944711629068049e-16))"
 };
 
+static std::string issue_1345_a[2] =
+{
+    // Needs check for opposite in handle_imperfect_touch
+    R""""(
+    POLYGON((
+        -2.0785311235613415 -0.6304193410175202,
+        -2.0534946127981359 -0.6304193410175202,
+        -2.0534946127981359 -0.8867932112327471,
+        -2.3098684830133629 -0.8867932112327471,
+        -2.3098684830133629 -0.6554558517807265,
+        -2.2848319722501573 -0.6554558517807265,
+        -2.0785311235613415 -0.6554558517807265,
+        -2.0785311235613415 -0.6304193410175202
+        ))
+    )"""",
+    R""""(
+    POLYGON((
+        -2.0785311235613420 -0.6304193410175202,
+        -2.0534946127981359 -0.6304193410175202,
+        -2.0534946127981359 -0.6554558517807265,
+        -2.0785311235613420 -0.6554558517807265,
+        -2.0785311235613420 -0.6304193410175202
+        ))
+    )""""
+};
+
+static std::string issue_1345_b[2] =
+{
+    // Needs check for opposite in handle_imperfect_touch
+    R""""(
+    POLYGON((
+        -6.1723606999999996 3.2834021000000000,
+        -6.1723606999999996 2.8006724999999992,
+        -5.7133718999999994 2.8006724999999992,
+        -5.7133718999999994 3.2834021000000000,
+        -5.6896310999999997 3.2834021000000000,
+        -5.6896310999999997 2.7769316999999996,
+        -6.1961014999999993 2.7769316999999996,
+        -6.1961014999999993 3.2834021000000000,
+        -6.1723606999999996 3.2834021000000000
+        ))
+    )"""",
+    R""""(
+    POLYGON((
+        -6.1723606999999996 2.8006724999999997,
+        -5.7133718999999994 2.8006724999999997,
+        -5.7133718999999994 2.7769316999999996,
+        -6.1723606999999996 2.7769316999999996,
+        -6.1723606999999996 2.8006724999999997
+        ))
+    )""""
+};
+
 static std::string ggl_list_20120229_volker[3] =
     {
     "POLYGON((1716 1554,2076 2250,2436 2352,2796 1248,3156 2484,3516 2688,3516 2688,3156 2484,2796 1248,2436 2352,2076 2250, 1716 1554))",

test/algorithms/set_operations/difference/difference.cpp

@@ -647,6 +647,9 @@ void test_all()
     TEST_DIFFERENCE(issue_1342_a, 2, 5.762381026454777, 0, 0.0, 2);
     TEST_DIFFERENCE(issue_1342_b, 2, 5.762381026454777, 1, 2.55e-14, 3);
 
+    TEST_DIFFERENCE(issue_1345_a, 1, 0.059308854, 0, 0.0, 1);
+    TEST_DIFFERENCE(issue_1345_b, 2, 0.024048025, 0, 0.0, 2);
+
     TEST_DIFFERENCE(mysql_21977775, 2, 160.856568913, 2, 92.3565689126, 4);
     TEST_DIFFERENCE(mysql_21965285, 1, 92.0, 1, 14.0, 1);
     TEST_DIFFERENCE(mysql_23023665_1, 1, 92.0, 1, 142.5, 2);

test/algorithms/set_operations/intersection/intersection.cpp

@@ -315,6 +315,9 @@ void test_areal()
     TEST_INTERSECTION(issue_1342_a, 1, -1, 43.05575);
     TEST_INTERSECTION(issue_1342_b, 1, -1, 43.05575);
 
+    TEST_INTERSECTION(issue_1345_a, 1, -1, 0.00062682687);
+    TEST_INTERSECTION(issue_1345_b, 1, -1, 0.010896761);
+
     test_one<Polygon, Polygon, Polygon>("buffer_mp1", buffer_mp1[0], buffer_mp1[1],
                 1, 31, 2.271707796);
     test_one<Polygon, Polygon, Polygon>("buffer_mp2", buffer_mp2[0], buffer_mp2[1],

test/algorithms/set_operations/union/union.cpp

@@ -493,6 +493,12 @@ void test_areal()
     TEST_UNION(issue_1342_b, 1, 0, -1, 48.81812749462214);
     TEST_UNION_REV(issue_1342_b, 1, 0, -1, 48.81812749462214);
 
+    TEST_UNION(issue_1345_a, 1, 0, -1, 0.059935681);
+    TEST_UNION_REV(issue_1345_a, 1, 0, -1, 0.059935681);
+
+    TEST_UNION(issue_1345_b, 1, 0, -1, 0.034944786);
+    TEST_UNION_REV(issue_1345_b, 1, 0, -1, 0.034944786);
+
     TEST_UNION(geos_1, 1, 0, -1, expectation_limits(3458.0, 3461.3203125));
     TEST_UNION(geos_2, 1, 0, -1, expectation_limits(349.0625, 350.55102539));
     TEST_UNION(geos_3, 1, 0, -1, 29391548.4998779);