QgsCurvePolygon::asGml3(): make output compliant when ring is not a LinearRing

that is when it is a ring made of a CircularString or a ring made of a CompoundCurve

Fixes qgis#57355

Author: rouault

src/core/geometry/qgscurvepolygon.cpp

@@ -356,24 +356,36 @@ QDomElement QgsCurvePolygon::asGml3( QDomDocument &doc, int precision, const QSt
   if ( isEmpty() )
     return elemCurvePolygon;
 
-  QDomElement elemExterior = doc.createElementNS( ns, QStringLiteral( "exterior" ) );
-  QDomElement curveElem = exteriorRing()->asGml3( doc, precision, ns, axisOrder );
-  if ( curveElem.tagName() == QLatin1String( "LineString" ) )
+  const auto exportRing = [&doc, precision, &ns, axisOrder]( const QgsCurve * ring )
   {
-    curveElem.setTagName( QStringLiteral( "LinearRing" ) );
-  }
-  elemExterior.appendChild( curveElem );
+    QDomElement ringElem = ring->asGml3( doc, precision, ns, axisOrder );
+    if ( ringElem.tagName() == QLatin1String( "LineString" ) )
+    {
+      ringElem.setTagName( QStringLiteral( "LinearRing" ) );
+    }
+    else if ( ringElem.tagName() == QLatin1String( "CompositeCurve" ) )
+    {
+      ringElem.setTagName( QStringLiteral( "Ring" ) );
+    }
+    else if ( ringElem.tagName() == QLatin1String( "Curve" ) )
+    {
+      QDomElement ringElemNew = doc.createElementNS( ns, QStringLiteral( "Ring" ) );
+      QDomElement curveMemberElem = doc.createElementNS( ns, QStringLiteral( "curveMember" ) );
+      ringElemNew.appendChild( curveMemberElem );
+      curveMemberElem.appendChild( ringElem );
+      ringElem = std::move( ringElemNew );
+    }
+    return ringElem;
+  };
+
+  QDomElement elemExterior = doc.createElementNS( ns, QStringLiteral( "exterior" ) );
+  elemExterior.appendChild( exportRing( exteriorRing() ) );
   elemCurvePolygon.appendChild( elemExterior );
 
   for ( int i = 0, n = numInteriorRings(); i < n; ++i )
   {
     QDomElement elemInterior = doc.createElementNS( ns, QStringLiteral( "interior" ) );
-    QDomElement innerRing = interiorRing( i )->asGml3( doc, precision, ns, axisOrder );
-    if ( innerRing.tagName() == QLatin1String( "LineString" ) )
-    {
-      innerRing.setTagName( QStringLiteral( "LinearRing" ) );
-    }
-    elemInterior.appendChild( innerRing );
+    elemInterior.appendChild( exportRing( interiorRing( i ) ) );
     elemCurvePolygon.appendChild( elemInterior );
   }
   return elemCurvePolygon;

tests/src/core/geometry/testqgscurvepolygon.cpp

@@ -65,6 +65,7 @@ class TestQgsCurvePolygon: public QObject
     void testWKB();
     void testWKT();
     void testExport();
+    void testExportOfCompoundCurveRing();
     void testCast();
     void removeInteriorRings_github_issue_49578();
 };
@@ -1738,7 +1739,7 @@ void TestQgsCurvePolygon::testExport()
   QGSCOMPAREGML( elemToString( QgsCurvePolygon().asGml2( doc ) ), expectedGML2empty );
 
   // as GML3
-  QString expectedSimpleGML3( QStringLiteral( "<Polygon xmlns=\"gml\"><exterior xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 1 0 11 2 0 12 1 0.5 13 0 0 10</posList></ArcString></segments></Curve></exterior></Polygon>" ) );
+  QString expectedSimpleGML3( QStringLiteral( "<Polygon xmlns=\"gml\"><exterior xmlns=\"gml\"><Ring xmlns=\"gml\"><curveMember xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 1 0 11 2 0 12 1 0.5 13 0 0 10</posList></ArcString></segments></Curve></curveMember></Ring></exterior></Polygon>" ) );
   res = elemToString( exportPolygon.asGml3( doc, 2 ) );
   QCOMPARE( elemToString( exportPolygon.asGml3( doc ) ), expectedSimpleGML3 );
 
@@ -1793,15 +1794,27 @@ void TestQgsCurvePolygon::testExport()
   QGSCOMPAREGML( res, expectedGML2prec2 );
 
   // as GML3
-  QString expectedGML3( QStringLiteral( "<Polygon xmlns=\"gml\"><exterior xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 1 0 11 2 0 12 1 0.5 13 0 0 10</posList></ArcString></segments></Curve></exterior><interior xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 0.10000000000000001 0 11 0.20000000000000001 0 12 0.10000000000000001 0.05 13 0 0 10</posList></ArcString></segments></Curve></interior></Polygon>" ) );
+  QString expectedGML3( QStringLiteral( "<Polygon xmlns=\"gml\"><exterior xmlns=\"gml\"><Ring xmlns=\"gml\"><curveMember xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 1 0 11 2 0 12 1 0.5 13 0 0 10</posList></ArcString></segments></Curve></curveMember></Ring></exterior><interior xmlns=\"gml\"><Ring xmlns=\"gml\"><curveMember xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 0.10000000000000001 0 11 0.20000000000000001 0 12 0.10000000000000001 0.05 13 0 0 10</posList></ArcString></segments></Curve></curveMember></Ring></interior></Polygon>" ) );
   res = elemToString( exportPolygon.asGml3( doc ) );
   QCOMPARE( res, expectedGML3 );
 
-  QString expectedGML3prec3( QStringLiteral( "<Polygon xmlns=\"gml\"><exterior xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 1 0 11 2 0 12 1 0.5 13 0 0 10</posList></ArcString></segments></Curve></exterior><interior xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 0.1 0 11 0.2 0 12 0.1 0.05 13 0 0 10</posList></ArcString></segments></Curve></interior></Polygon>" ) );
+  QString expectedGML3prec3( QStringLiteral( "<Polygon xmlns=\"gml\"><exterior xmlns=\"gml\"><Ring xmlns=\"gml\"><curveMember xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 1 0 11 2 0 12 1 0.5 13 0 0 10</posList></ArcString></segments></Curve></curveMember></Ring></exterior><interior xmlns=\"gml\"><Ring xmlns=\"gml\"><curveMember xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"3\">0 0 10 0.1 0 11 0.2 0 12 0.1 0.05 13 0 0 10</posList></ArcString></segments></Curve></curveMember></Ring></interior></Polygon>" ) );
   res = elemToString( exportPolygon.asGml3( doc, 3 ) );
   QCOMPARE( res, expectedGML3prec3 );
 }
 
+void TestQgsCurvePolygon::testExportOfCompoundCurveRing()
+{
+  QgsCurvePolygon curvePoly;
+  curvePoly.fromWkt( QStringLiteral( "CURVEPOLYGON (COMPOUNDCURVE ((0 -1,0 1),CIRCULARSTRING (0 1,1 0,0 -1)))" ) );
+
+  // as GML3
+  QString expectedGML3( QStringLiteral( "<Polygon xmlns=\"gml\"><exterior xmlns=\"gml\"><Ring xmlns=\"gml\"><curveMember xmlns=\"gml\"><LineString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"2\">0 -1 0 1</posList></LineString></curveMember><curveMember xmlns=\"gml\"><Curve xmlns=\"gml\"><segments xmlns=\"gml\"><ArcString xmlns=\"gml\"><posList xmlns=\"gml\" srsDimension=\"2\">0 1 1 0 0 -1</posList></ArcString></segments></Curve></curveMember></Ring></exterior></Polygon>" ) );
+  QDomDocument doc( QStringLiteral( "gml" ) );
+  QString res = elemToString( curvePoly.asGml3( doc ) );
+  QCOMPARE( res, expectedGML3 );
+}
+
 void TestQgsCurvePolygon::testCast()
 {
   QVERIFY( !QgsCurvePolygon().cast( nullptr ) );