Fix reshape line tool fails when reshape line partially exactly

overlaps geometry (cherry picked from commit 37de804)
qgis · Nov 20, 2020 · ad49096 · ad49096
1 parent 9a075a4
commit ad49096
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Showing 2 changed files with 32 additions and 2 deletions.
diff --git a/src/core/geometry/qgsgeos.cpp b/src/core/geometry/qgsgeos.cpp
@@ -2439,8 +2439,10 @@ geos::unique_ptr QgsGeos::reshapeLine( const GEOSGeometry *line, const GEOSGeome
     geos::unique_ptr intersectGeom( GEOSIntersection_r( geosinit.ctxt, line, reshapeLineGeos ) );
     if ( intersectGeom )
     {
-      atLeastTwoIntersections = ( GEOSGeomTypeId_r( geosinit.ctxt, intersectGeom.get() ) == GEOS_MULTIPOINT
-                                  && GEOSGetNumGeometries_r( geosinit.ctxt, intersectGeom.get() ) > 1 );
+      const int geomType = GEOSGeomTypeId_r( geosinit.ctxt, intersectGeom.get() );
+      atLeastTwoIntersections = ( geomType == GEOS_MULTIPOINT && GEOSGetNumGeometries_r( geosinit.ctxt, intersectGeom.get() ) > 1 )
+                                || ( geomType == GEOS_GEOMETRYCOLLECTION && GEOSGetNumGeometries_r( geosinit.ctxt, intersectGeom.get() ) > 0 ) // a collection implies at least two points!
+                                || ( geomType == GEOS_MULTILINESTRING && GEOSGetNumGeometries_r( geosinit.ctxt, intersectGeom.get() ) > 0 );
       // one point is enough when extending line at its endpoint
       if ( GEOSGeomTypeId_r( geosinit.ctxt, intersectGeom.get() ) == GEOS_POINT )
       {

diff --git a/tests/src/python/test_qgsgeometry.py b/tests/src/python/test_qgsgeometry.py
@@ -2358,6 +2358,14 @@ def testRegression13274(self):
 
     def testReshape(self):
         """ Test geometry reshaping """
+
+        # no overlap
+        g = QgsGeometry.fromWkt('LineString (0 0, 5 0, 5 1, 6 1, 6 0, 7 0)')
+        self.assertEqual(g.reshapeGeometry(QgsLineString([QgsPoint(4, 2), QgsPoint(7, 2)])), 0)
+        expWkt = 'LineString (0 0, 5 0, 5 1, 6 1, 6 0, 7 0)'
+        wkt = g.asWkt()
+        self.assertTrue(compareWkt(expWkt, wkt), "testReshape failed: mismatch Expected:\n%s\nGot:\n%s\n" % (expWkt, wkt))
+
         g = QgsGeometry.fromWkt('Polygon ((0 0, 1 0, 1 1, 0 1, 0 0))')
         g.reshapeGeometry(QgsLineString([QgsPoint(0, 1.5), QgsPoint(1.5, 0)]))
         expWkt = 'Polygon ((0.5 1, 0 1, 0 0, 1 0, 1 0.5, 0.5 1))'
@@ -2408,6 +2416,26 @@ def testReshape(self):
         wkt = g.asWkt()
         assert compareWkt(expWkt, wkt), "testReshape failed: mismatch Expected:\n%s\nGot:\n%s\n" % (expWkt, wkt)
 
+        # reshape where reshape line exactly overlaps some portions of geometry
+        g = QgsGeometry.fromWkt('LineString (0 0, 5 0, 5 1, 6 1, 6 0, 7 0)')
+        self.assertEqual(g.reshapeGeometry(QgsLineString([QgsPoint(2, 0), QgsPoint(6, 0)])), 0)
+        expWkt = 'LineString (0 0, 2 0, 5 0, 6 0, 7 0)'
+        wkt = g.asWkt()
+        self.assertTrue(compareWkt(expWkt, wkt), "testReshape failed: mismatch Expected:\n%s\nGot:\n%s\n" % (expWkt, wkt))
+
+        g = QgsGeometry.fromWkt('LineString (0 0, 5 0, 5 1, 6 1, 6 0, 7 0)')
+        self.assertEqual(g.reshapeGeometry(QgsLineString([QgsPoint(5, 0), QgsPoint(7, 0)])), 0)
+        expWkt = 'LineString (0 0, 5 0, 6 0, 7 0)'
+        wkt = g.asWkt()
+        self.assertTrue(compareWkt(expWkt, wkt), "testReshape failed: mismatch Expected:\n%s\nGot:\n%s\n" % (expWkt, wkt))
+
+        # reshape line overlaps at both start and end
+        g = QgsGeometry.fromWkt('LineString (0 0, 5 0, 5 1, 6 1, 6 0, 7 0)')
+        self.assertEqual(g.reshapeGeometry(QgsLineString([QgsPoint(4, 0), QgsPoint(7, 0)])), 0)
+        expWkt = 'LineString (0 0, 4 0, 5 0, 6 0, 7 0)'
+        wkt = g.asWkt()
+        self.assertTrue(compareWkt(expWkt, wkt), "testReshape failed: mismatch Expected:\n%s\nGot:\n%s\n" % (expWkt, wkt))
+
     def testConvertToMultiType(self):
         """ Test converting geometries to multi type """
         point = QgsGeometry.fromWkt('Point (1 2)')