Fix removing whole ring by progressively deleting nodes (fix #13099)

nyalldawson · nyalldawson · commit acd8f26a914e · 2015-09-09T16:51:00.000+10:00
diff --git a/src/core/geometry/qgscurvepolygonv2.cpp b/src/core/geometry/qgscurvepolygonv2.cpp
@@ -626,10 +626,26 @@ bool QgsCurvePolygonV2::deleteVertex( const QgsVertexId& vId )
 
   QgsCurveV2* ring = vId.ring == 0 ? mExteriorRing : mInteriorRings[vId.ring - 1];
   int n = ring->numPoints();
-  if ( n <= 4 )
+  if ( n <= 2 )
   {
-    return false;
+    //no points will be left in ring, so remove whole ring
+    if ( vId.ring == 0 )
+    {
+      delete mExteriorRing;
+      mExteriorRing = 0;
+      if ( !mInteriorRings.isEmpty() )
+      {
+        mExteriorRing = mInteriorRings.takeFirst();
+      }
+    }
+    else
+    {
+      removeInteriorRing( vId.ring - 1 );
+    }
+    mBoundingBox = QgsRectangle();
+    return true;
   }
+
   bool success = ring->deleteVertex( vId );
   if ( success )
   {
diff --git a/tests/src/python/test_qgsgeometry.py b/tests/src/python/test_qgsgeometry.py
@@ -979,7 +979,7 @@ def testDeleteVertex(self):
         # |                 |
         # 0-+-+-+-+---+-+-+-1
         polygon = QgsGeometry.fromWkt("Polygon ((0 0, 9 0, 9 3, 0 3, 0 0),(1 1, 2 1, 2 2, 1 2, 1 1),(3 1, 4 1, 4 2, 3 2, 3 1),(5 1, 6 1, 6 2, 5 2, 5 1),(7 1, 8 1, 8 2, 7 2, 7 1))")
-        #                                          0   1   2   3   4     5   6   7   8   9    10  11  12  13  14    15  16  17  18  19    20  21  22  23  24
+        #                                         0   1    2    3    4     5    6    7    8    9     10   11   12   13   14    15   16   17   18   19    20  21   22   23   24
 
         for i in range(4):
             assert polygon.deleteVertex(16), "Delete vertex 16 failed" % i
@@ -996,6 +996,15 @@ def testDeleteVertex(self):
         wkt = polygon.exportToWkt()
         assert compareWkt(expwkt, wkt), "Expected:\n%s\nGot:\n%s\n" % (expwkt, wkt)
 
+        #Remove whole outer ring, inner ring should become outer
+        polygon = QgsGeometry.fromWkt("Polygon ((0 0, 9 0, 9 3, 0 3, 0 0),(1 1, 2 1, 2 2, 1 2, 1 1))")
+        for i in range(4):
+            assert polygon.deleteVertex(0), "Delete vertex 16 failed" % i
+
+        expwkt = "Polygon ((1 1, 2 1, 2 2, 1 2, 1 1))"
+        wkt = polygon.exportToWkt()
+        assert compareWkt(expwkt, wkt), "Expected:\n%s\nGot:\n%s\n" % (expwkt, wkt)
+
     def testInsertVertex(self):
         linestring = QgsGeometry.fromWkt("LineString(1 0, 2 0)")
 
