[vectortiles] Be tolerant, and allow rendering polygon features

using a line style Some services use line styles for polygon symbology in order to specify that the polygons should be rendered using their outlines in a line style
qgis · Aug 31, 2020 · 4cd40ab · 4cd40ab
1 parent fc01144
commit 4cd40ab
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Showing 3 changed files with 56 additions and 3 deletions.
diff --git a/src/core/vectortile/qgsvectortilebasicrenderer.cpp b/src/core/vectortile/qgsvectortilebasicrenderer.cpp
@@ -24,7 +24,6 @@
 #include "qgssymbollayerutils.h"
 #include "qgsvectortileutils.h"
 
-
 QgsVectorTileBasicRendererStyle::QgsVectorTileBasicRendererStyle( const QString &stName, const QString &laName, QgsWkbTypes::GeometryType geomType )
   : mStyleName( stName )
   , mLayerName( laName )
@@ -171,8 +170,19 @@ void QgsVectorTileBasicRenderer::renderTile( const QgsVectorTileRendererData &ti
           if ( filterExpression.isValid() && !filterExpression.evaluate( &context.expressionContext() ).toBool() )
             continue;
 
-          if ( QgsWkbTypes::geometryType( f.geometry().wkbType() ) == layerStyle.geometryType() )
+          const QgsWkbTypes::GeometryType featureType = QgsWkbTypes::geometryType( f.geometry().wkbType() );
+          if ( featureType == layerStyle.geometryType() )
+          {
             sym->renderFeature( f, context );
+          }
+          else if ( featureType == QgsWkbTypes::PolygonGeometry && layerStyle.geometryType() == QgsWkbTypes::LineGeometry )
+          {
+            // be tolerant and permit rendering polygons with a line layer style, as some style definitions use this approach
+            // to render the polygon borders only
+            QgsFeature exterior = f;
+            exterior.setGeometry( QgsGeometry( f.geometry().constGet()->boundary() ) );
+            sym->renderFeature( exterior, context );
+          }
         }
       }
     }
@@ -185,8 +195,19 @@ void QgsVectorTileBasicRenderer::renderTile( const QgsVectorTileRendererData &ti
         if ( filterExpression.isValid() && !filterExpression.evaluate( &context.expressionContext() ).toBool() )
           continue;
 
-        if ( QgsWkbTypes::geometryType( f.geometry().wkbType() ) == layerStyle.geometryType() )
+        const QgsWkbTypes::GeometryType featureType = QgsWkbTypes::geometryType( f.geometry().wkbType() );
+        if ( featureType == layerStyle.geometryType() )
+        {
           sym->renderFeature( f, context );
+        }
+        else if ( featureType == QgsWkbTypes::PolygonGeometry && layerStyle.geometryType() == QgsWkbTypes::LineGeometry )
+        {
+          // be tolerant and permit rendering polygons with a line layer style, as some style definitions use this approach
+          // to render the polygon borders only
+          QgsFeature exterior = f;
+          exterior.setGeometry( QgsGeometry( f.geometry().constGet()->boundary() ) );
+          sym->renderFeature( exterior, context );
+        }
       }
     }
     sym->stopRender( context );

diff --git a/tests/src/core/testqgsvectortilelayer.cpp b/tests/src/core/testqgsvectortilelayer.cpp
@@ -26,6 +26,7 @@
 #include "qgsvectortilelayer.h"
 #include "qgsvectortilebasiclabeling.h"
 #include "qgsfontutils.h"
+#include "qgslinesymbollayer.h"
 
 /**
  * \ingroup UnitTests
@@ -57,6 +58,7 @@ class TestQgsVectorTileLayer : public QObject
     void test_render_withClip();
     void test_labeling();
     void test_relativePaths();
+    void test_polygonWithLineStyle();
 };
 
 
@@ -242,6 +244,36 @@ void TestQgsVectorTileLayer::test_relativePaths()
   QCOMPARE( layer.decodedSource( srcMbtiles, QString(), contextAbs ), srcMbtiles );
 }
 
+void TestQgsVectorTileLayer::test_polygonWithLineStyle()
+{
+  QgsDataSourceUri ds;
+  ds.setParam( "type", "xyz" );
+  ds.setParam( "url", QString( "file://%1/{z}-{x}-{y}.pbf" ).arg( mDataDir ) );
+  ds.setParam( "zmax", "1" );
+  std::unique_ptr< QgsVectorTileLayer > layer = qgis::make_unique< QgsVectorTileLayer >( ds.encodedUri(), "Vector Tiles Test" );
+  QVERIFY( layer->isValid() );
+
+  mMapSettings->setLayers( QList<QgsMapLayer *>() << layer.get() );
+
+  QColor lineStrokeColor = Qt::blue;
+  double lineStrokeWidth = DEFAULT_LINE_WIDTH * 2;
+
+  QgsVectorTileBasicRenderer *rend = new QgsVectorTileBasicRenderer;
+
+  QgsSimpleLineSymbolLayer *lineSymbolLayer = new QgsSimpleLineSymbolLayer;
+  lineSymbolLayer->setColor( lineStrokeColor );
+  lineSymbolLayer->setWidth( lineStrokeWidth );
+  QgsLineSymbol *lineSymbol = new QgsLineSymbol( QgsSymbolLayerList() << lineSymbolLayer );
+
+  QgsVectorTileBasicRendererStyle st( QStringLiteral( "Polygons" ), QString(), QgsWkbTypes::LineGeometry );
+  st.setSymbol( lineSymbol );
+
+  rend->setStyles( QList<QgsVectorTileBasicRendererStyle>() << st );
+  layer->setRenderer( rend );  // takes ownership
+
+  QVERIFY( imageCheck( "render_test_polygon_with_line_style", layer.get(), layer->extent() ) );
+}
+
 
 QGSTEST_MAIN( TestQgsVectorTileLayer )
 #include "testqgsvectortilelayer.moc"
diff --git a/...r_test_polygon_with_line_style/expected_render_test_polygon_with_line_style.png b/...r_test_polygon_with_line_style/expected_render_test_polygon_with_line_style.png