[geometry snapper] Don't create invalid geometries with duplicate nodes

Fixes #15247
qgis · Dec 3, 2017 · 113c21e · 113c21e
1 parent 484a611
commit 113c21e
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Showing 2 changed files with 36 additions and 2 deletions.
diff --git a/src/analysis/vector/qgsgeometrysnapper.cpp b/src/analysis/vector/qgsgeometrysnapper.cpp
@@ -608,7 +608,11 @@ QgsGeometry QgsGeometrySnapper::snapGeometry( const QgsGeometry &geometry, doubl
     return QgsGeometry( subjGeom );
   //or for end point snapping
   if ( mode == PreferClosestNoExtraVertices || mode == PreferNodesNoExtraVertices || mode == EndPointPreferClosest || mode == EndPointPreferNodes || mode == EndPointToEndPoint )
-    return QgsGeometry( subjGeom );
+  {
+    QgsGeometry result( subjGeom );
+    result.removeDuplicateNodes();
+    return result;
+  }
 
   // SnapIndex for subject feature
   std::unique_ptr< QgsSnapIndex > subjSnapIndex( new QgsSnapIndex( center, 10 * snapTolerance ) );
@@ -705,7 +709,9 @@ QgsGeometry QgsGeometrySnapper::snapGeometry( const QgsGeometry &geometry, doubl
     }
   }
 
-  return QgsGeometry( subjGeom );
+  QgsGeometry result( subjGeom );
+  result.removeDuplicateNodes();
+  return result;
 }
 
 int QgsGeometrySnapper::polyLineSize( const QgsAbstractGeometry *geom, int iPart, int iRing )

diff --git a/tests/src/analysis/testqgsgeometrysnapper.cpp b/tests/src/analysis/testqgsgeometrysnapper.cpp
@@ -49,6 +49,7 @@ class TestQgsGeometrySnapper : public QObject
     void endPointToEndPoint();
     void internalSnapper();
     void insertExtra();
+    void duplicateNodes();
 };
 
 void  TestQgsGeometrySnapper::initTestCase()
@@ -584,6 +585,33 @@ void TestQgsGeometrySnapper::insertExtra()
 
 }
 
+void TestQgsGeometrySnapper::duplicateNodes()
+{
+  // test that snapper does not result in duplicate nodes
+
+  QgsGeometry refGeom = QgsGeometry::fromWkt( QStringLiteral( "LineString(0 0, 20 0)" ) );
+  QgsFeature f1( 1 );
+  f1.setGeometry( refGeom );
+
+  QgsInternalGeometrySnapper snapper( 2, QgsGeometrySnapper::PreferNodes );
+  QgsGeometry result = snapper.snapFeature( f1 );
+  QCOMPARE( result.asWkt(), f1.geometry().asWkt() );
+
+  refGeom = QgsGeometry::fromWkt( QStringLiteral( "LineString(10 10, 19 0, 19.5 1, 20 0.1)" ) );
+  QgsFeature f2( 2 );
+  f2.setGeometry( refGeom );
+  result = snapper.snapFeature( f2 );
+  QCOMPARE( result.asWkt( 1 ), QStringLiteral( "LineString (10 10, 20 0)" ) );
+
+  snapper = QgsInternalGeometrySnapper( 2, QgsGeometrySnapper::PreferNodesNoExtraVertices );
+  result = snapper.snapFeature( f1 );
+  QCOMPARE( result.asWkt(), f1.geometry().asWkt() );
+
+  result = snapper.snapFeature( f2 );
+  QCOMPARE( result.asWkt( 1 ), QStringLiteral( "LineString (10 10, 20 0)" ) );
+
+}
+
 
 QGSTEST_MAIN( TestQgsGeometrySnapper )
 #include "testqgsgeometrysnapper.moc"