Fix (0,0) points are ignored when calculating the bounding box for a …

…multipoint geometry
qgis · Apr 10, 2020 · 9dcc9dc · 9dcc9dc
1 parent 95ae4b4
commit 9dcc9dc
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Showing 2 changed files with 36 additions and 1 deletion.
diff --git a/src/core/geometry/qgsgeometrycollection.cpp b/src/core/geometry/qgsgeometrycollection.cpp
@@ -477,8 +477,28 @@ QgsRectangle QgsGeometryCollection::calculateBoundingBox() const
   QgsRectangle bbox = mGeometries.at( 0 )->boundingBox();
   for ( int i = 1; i < mGeometries.size(); ++i )
   {
+    if ( mGeometries.at( i )->isEmpty() )
+      continue;
+
     QgsRectangle geomBox = mGeometries.at( i )->boundingBox();
-    bbox.combineExtentWith( geomBox );
+    if ( bbox.isNull() )
+    {
+      // workaround treatment of a QgsRectangle(0,0,0,0) as a "null"/invalid rectangle
+      // if bbox is null, then the first geometry must have returned a bounding box of (0,0,0,0)
+      // so just manually include that as a point... ew.
+      geomBox.combineExtentWith( QPointF( 0, 0 ) );
+      bbox = geomBox;
+    }
+    else if ( geomBox.isNull() )
+    {
+      // ...as above... this part must have a bounding box of (0,0,0,0).
+      // if we try to combine the extent with this "null" box it will just be ignored.
+      bbox.combineExtentWith( QPointF( 0, 0 ) );
+    }
+    else
+    {
+      bbox.combineExtentWith( geomBox );
+    }
   }
   return bbox;
 }

diff --git a/tests/src/core/testqgsgeometry.cpp b/tests/src/core/testqgsgeometry.cpp
@@ -12259,6 +12259,21 @@ void TestQgsGeometry::multiPoint()
   pCast2.fromWkt( QStringLiteral( "MultiPointZM(PointZM(0 1 1 2))" ) );
   QVERIFY( QgsMultiPoint().cast( &pCast2 ) );
 
+  // bounding box
+  QgsMultiPoint boundingBox;
+  boundingBox.addGeometry( new QgsPoint( 0, 0 ) );
+  QCOMPARE( boundingBox.boundingBox(), QgsRectangle( 0, 0, 0, 0 ) );
+  boundingBox.addGeometry( new QgsPoint( 1, 2 ) );
+  QCOMPARE( boundingBox.boundingBox(), QgsRectangle( 0, 0, 1, 2 ) );
+  QgsMultiPoint boundingBox2;
+  QCOMPARE( boundingBox2.boundingBox(), QgsRectangle( 0, 0, 0, 0 ) );
+  boundingBox2.addGeometry( new QgsPoint( 1, 2 ) );
+  QCOMPARE( boundingBox2.boundingBox(), QgsRectangle( 1, 2, 1, 2 ) );
+  boundingBox2.addGeometry( new QgsPoint( 10, 3 ) );
+  QCOMPARE( boundingBox2.boundingBox(), QgsRectangle( 1, 2, 10, 3 ) );
+  boundingBox2.addGeometry( new QgsPoint( 0, 0 ) );
+  QCOMPARE( boundingBox2.boundingBox(), QgsRectangle( 0, 0, 10, 3 ) );
+
   //boundary
 
   //multipoints have no boundary defined