Fix OverlayNG handling of flat interior line

libgeos · Feb 9, 2021 · e309558 · e309558
1 parent df1d6c9
commit e309558
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diff --git a/src/operation/overlayng/OverlayUtil.cpp b/src/operation/overlayng/OverlayUtil.cpp
@@ -48,6 +48,10 @@ OverlayUtil::safeExpandDistance(const Envelope* env, const PrecisionModel* pm)
     if (isFloating(pm)) {
         // if PM is FLOAT then there is no scale factor, so add 10%
         double minSize = std::min(env->getHeight(), env->getWidth());
+        // heuristic to ensure zero-width envelopes don't cause total clipping
+        if (minSize <= 0.0) {
+            minSize = std::max(env->getHeight(), env->getWidth());
+        }
         envExpandDist = SAFE_ENV_BUFFER_FACTOR * minSize;
     }
     else {

diff --git a/tests/unit/operation/overlayng/OverlayNGTest.cpp b/tests/unit/operation/overlayng/OverlayNGTest.cpp
@@ -553,10 +553,33 @@ template<>
 template<>
 void object::test<43> ()
 {
+    set_test_name("testPolygonLineIntersectionOrder");
     std::string a = "POLYGON ((1 1, 1 9, 9 9, 9 7, 3 7, 3 3, 9 3, 9 1, 1 1))";
     std::string b = "MULTILINESTRING ((2 10, 2 0), (4 10, 4 0))";
     std::string exp = "MULTILINESTRING ((2 9, 2 1), (4 9, 4 7), (4 3, 4 1))";
     testOverlay(a, b, exp, OverlayNG::INTERSECTION, 0);
 }
 
+template<>
+template<>
+void object::test<44> ()
+{
+    set_test_name("testPolygonLineVerticalntersection");
+    std::string a = "POLYGON ((-200 -200, 200 -200, 200 200, -200 200, -200 -200))";
+    std::string b = "LINESTRING (-100 100, -100 -100)";
+    std::string exp = "LINESTRING (-100 100, -100 -100)";
+    testOverlay(a, b, exp, OverlayNG::INTERSECTION, 0);
+}
+
+template<>
+template<>
+void object::test<45> ()
+{
+    set_test_name("testPolygonLineHorizontalIntersection");
+    std::string a = "POLYGON ((10 90, 90 90, 90 10, 10 10, 10 90))";
+    std::string b = "LINESTRING (20 50, 80 50)";
+    std::string exp = "LINESTRING (20 50, 80 50)";
+    testOverlay(a, b, exp, OverlayNG::INTERSECTION, 0);
+}
+
 } // namespace tut
diff --git a/tests/xmltester/tests/general/TestNGOverlayL.xml b/tests/xmltester/tests/general/TestNGOverlayL.xml
@@ -204,6 +204,31 @@ MULTILINESTRING ((150 150, 200 200, 300 300, 400 200), (100 100, 150 150), (190
   </op></test>
 </case>
 
+<case>
+  <desc>LA - vertical Line</desc>
+  <a>
+    LINESTRING (50 50, 50 20)
+  </a>
+  <b>
+    POLYGON ((10 60, 90 60, 90 10, 10 10, 10 60))
+  </b>
+<test>  <op name="intersectionNG" arg1="A" arg2="B">
+LINESTRING (50 50, 50 20)
+  </op></test>
+<test>  <op name="unionNG" arg1="A" arg2="B">
+POLYGON ((90 60, 90 10, 10 10, 10 60, 90 60))
+  </op></test>
+<test>  <op name="differenceNG" arg1="A" arg2="B">
+LINESTRING EMPTY
+  </op></test>
+<test>  <op name="differenceNG" arg1="B" arg2="A">
+POLYGON ((90 60, 90 10, 10 10, 10 60, 90 60))
+  </op></test>
+<test>  <op name="symdifferenceNG" arg1="A" arg2="B">
+POLYGON ((90 60, 90 10, 10 10, 10 60, 90 60))
+  </op></test>
+</case>
+
 <case>
   <desc>mLmA - disjoint and overlaps in lines and points</desc>
   <a>