Fixes #49728 : Fix layout legend when geometry generator is involved

src/core/layertree/qgslayertreemodellegendnode.cpp

@@ -687,11 +687,15 @@ QSizeF QgsSymbolLegendNode::drawSymbol( const QgsLegendSettings &settings, ItemC
   if ( QgsMarkerSymbol *markerSymbol = dynamic_cast<QgsMarkerSymbol *>( s ) )
   {
     const double size = markerSymbol->size( *context ) / context->scaleFactor();
-    height = size;
-    width = size;
+    if ( size > 0 )
+    {
+      height = size;
+      width = size;
+    }
   }
 
-  const std::unique_ptr<QgsSymbol> minMaxSizeSymbol( QgsSymbolLayerUtils::restrictedSizeSymbol( s, minSymbolSize, maxSymbolSize, context, width, height ) );
+  bool restrictedSizeSymbolOK;
+  const std::unique_ptr<QgsSymbol> minMaxSizeSymbol( QgsSymbolLayerUtils::restrictedSizeSymbol( s, minSymbolSize, maxSymbolSize, context, width, height, &restrictedSizeSymbolOK ) );
   if ( minMaxSizeSymbol )
   {
     s = minMaxSizeSymbol.get();
@@ -739,12 +743,14 @@ QSizeF QgsSymbolLegendNode::drawSymbol( const QgsLegendSettings &settings, ItemC
     // QGIS 4.0 -- ctx->context will be mandatory
     const bool useAdvancedEffects = ctx->context ? ctx->context->flags() & Qgis::RenderContextFlag::UseAdvancedEffects : settings.useAdvancedEffects();
     Q_NOWARN_DEPRECATED_POP
+
     if ( opacity != 255 && useAdvancedEffects )
     {
+      // if this is a semi transparent layer, we need to draw symbol to an image (to flatten it first)
+
       const int maxBleed = static_cast< int >( std::ceil( QgsSymbolLayerUtils::estimateMaxSymbolBleed( s, *context ) ) );
 
-      //semi transparent layer, so need to draw symbol to an image (to flatten it first)
-      //create image which is same size as legend rect, in case symbol bleeds outside its allotted space
+      // create image which is same size as legend rect, in case symbol bleeds outside its allotted space
       const QSize symbolSize( static_cast< int >( std::round( width * dotsPerMM ) ), static_cast<int >( std::round( height * dotsPerMM ) ) );
       const QSize tempImageSize( symbolSize.width() + maxBleed * 2, symbolSize.height() + maxBleed * 2 );
       QImage tempImage = QImage( tempImageSize, QImage::Format_ARGB32 );
@@ -764,6 +770,18 @@ QSizeF QgsSymbolLegendNode::drawSymbol( const QgsLegendSettings &settings, ItemC
       //draw rendered symbol image
       p->drawImage( -maxBleed, -maxBleed, tempImage );
     }
+    else if ( !restrictedSizeSymbolOK )
+    {
+      // if there is no restricted symbol size (because of geometry generator mainly) we need to ensure
+      // that there is no drawing outside the given size
+      const int maxBleed = static_cast< int >( std::ceil( QgsSymbolLayerUtils::estimateMaxSymbolBleed( s, *context ) ) );
+      const QSize symbolSize( static_cast< int >( std::round( width * dotsPerMM ) ), static_cast<int >( std::round( height * dotsPerMM ) ) );
+      const QSize maxSize( symbolSize.width() + maxBleed * 2, symbolSize.height() + maxBleed * 2 );
+      p->save();
+      p->setClipRect( -maxBleed, -maxBleed, maxSize.width(), maxSize.height(), Qt::IntersectClip );
+      s->drawPreviewIcon( p, symbolSize, context, false, nullptr, &patchShape );
+      p->restore();
+    }
     else
     {
       s->drawPreviewIcon( p, QSize( static_cast< int >( std::round( width * dotsPerMM ) ), static_cast< int >( std::round( height * dotsPerMM ) ) ), context, false, nullptr, &patchShape );

src/core/symbology/qgssymbollayerutils.cpp

@@ -5067,6 +5067,19 @@ QgsSymbol *QgsSymbolLayerUtils::restrictedSizeSymbol( const QgsSymbol *s, double
   }
   else if ( lineSymbol )
   {
+    const QgsSymbolLayerList sls = s->symbolLayers();
+    for ( const QgsSymbolLayer *sl : std::as_const( sls ) )
+    {
+      // geometry generators involved, there is no way to get a restricted size symbol
+      if ( sl->type() != Qgis::SymbolType::Line )
+      {
+        if ( ok )
+          *ok = false;
+
+        return nullptr;
+      }
+    }
+
     size = lineSymbol->width( *context );
   }
   else

tests/src/python/test_qgslayoutlegend.py

@@ -18,8 +18,11 @@
     QgsCategorizedSymbolRenderer,
     QgsCoordinateReferenceSystem,
     QgsExpression,
+    QgsFeature,
     QgsFillSymbol,
     QgsFontUtils,
+    QgsGeometry,
+    QgsGeometryGeneratorSymbolLayer,
     QgsLayout,
     QgsLayoutItem,
     QgsLayoutItemLegend,
@@ -41,7 +44,9 @@
     QgsRendererCategory,
     QgsRuleBasedRenderer,
     QgsSingleSymbolRenderer,
-    QgsVectorLayer,
+    QgsSymbol,
+    QgsTextFormat,
+    QgsVectorLayer
 )
 from qgis.testing import start_app, unittest
 
@@ -895,6 +900,134 @@ def test_rulebased_child_filter(self):
         TestQgsLayoutItemLegend.report += checker.report()
         self.assertTrue(result, message)
 
+    def testGeomGeneratorPoints(self):
+        """Test legend behavior when geometry generator on points is involved"""
+        point_path = os.path.join(TEST_DATA_DIR, 'points.shp')
+        point_layer = QgsVectorLayer(point_path, 'points', 'ogr')
+        QgsProject.instance().addMapLayers([point_layer])
+
+        sub_symbol = QgsFillSymbol.createSimple({'color': '#8888ff', 'outline_style': 'no'})
+        sym = QgsMarkerSymbol()
+        buffer_layer = QgsGeometryGeneratorSymbolLayer.create(
+            {'geometryModifier': 'buffer($geometry, 0.05)'})
+        buffer_layer.setSymbolType(QgsSymbol.Fill)
+        buffer_layer.setSubSymbol(sub_symbol)
+        sym.changeSymbolLayer(0, buffer_layer)
+        point_layer.setRenderer(QgsSingleSymbolRenderer(sym))
+
+        s = QgsMapSettings()
+        s.setLayers([point_layer])
+        layout = QgsLayout(QgsProject.instance())
+        layout.initializeDefaults()
+
+        map = QgsLayoutItemMap(layout)
+        map.attemptSetSceneRect(QRectF(20, 20, 80, 80))
+        map.setFrameEnabled(True)
+        map.setLayers([point_layer])
+        layout.addLayoutItem(map)
+
+        legend = QgsLayoutItemLegend(layout)
+        legend.setTitle("Legend")
+        legend.attemptSetSceneRect(QRectF(120, 20, 80, 80))
+        legend.setFrameEnabled(True)
+        legend.setFrameStrokeWidth(QgsLayoutMeasurement(2))
+        legend.setBackgroundColor(QColor(200, 200, 200))
+        legend.setTitle('')
+        legend.setLegendFilterByMapEnabled(True)
+        legend.setSymbolWidth(20)
+        legend.setSymbolHeight(10)
+
+        text_format = QgsTextFormat()
+        text_format.setFont(QgsFontUtils.getStandardTestFont("Bold"))
+        text_format.setSize(16)
+
+        for legend_item in [QgsLegendStyle.Title, QgsLegendStyle.Group, QgsLegendStyle.Subgroup,
+                            QgsLegendStyle.Symbol, QgsLegendStyle.SymbolLabel]:
+            style = legend.style(legend_item)
+            style.setTextFormat(text_format)
+            legend.setStyle(legend_item, style)
+
+        # disable auto resizing
+        legend.setResizeToContents(False)
+
+        layout.addLayoutItem(legend)
+        legend.setLinkedMap(map)
+
+        map.setExtent(QgsRectangle(-102.51, 41.16, -102.36, 41.30))
+
+        checker = QgsLayoutChecker(
+            'composer_legend_geomgenerator_point', layout)
+        checker.setControlPathPrefix("composer_legend")
+        result, message = checker.testLayout()
+        TestQgsLayoutItemLegend.report += checker.report()
+        self.assertTrue(result, message)
+        QgsProject.instance().removeMapLayers([point_layer.id()])
+
+    def testGeomGeneratorLines(self):
+        """Test legend behavior when geometry generator on lines is involved"""
+        line_path = os.path.join(TEST_DATA_DIR, 'lines.shp')
+        line_layer = QgsVectorLayer(line_path, 'lines', 'ogr')
+        QgsProject.instance().addMapLayers([line_layer])
+
+        sub_symbol = QgsFillSymbol.createSimple({'color': '#8888ff', 'outline_style': 'no'})
+        sym = QgsLineSymbol()
+        buffer_layer = QgsGeometryGeneratorSymbolLayer.create(
+            {'geometryModifier': 'buffer($geometry, 0.2)'})
+        buffer_layer.setSymbolType(QgsSymbol.Fill)
+        buffer_layer.setSubSymbol(sub_symbol)
+        sym.changeSymbolLayer(0, buffer_layer)
+        line_layer.setRenderer(QgsSingleSymbolRenderer(sym))
+
+        s = QgsMapSettings()
+        s.setLayers([line_layer])
+        layout = QgsLayout(QgsProject.instance())
+        layout.initializeDefaults()
+
+        map = QgsLayoutItemMap(layout)
+        map.attemptSetSceneRect(QRectF(20, 20, 80, 80))
+        map.setFrameEnabled(True)
+        map.setLayers([line_layer])
+        layout.addLayoutItem(map)
+        map.setExtent(line_layer.extent())
+
+        legend = QgsLayoutItemLegend(layout)
+        legend.setTitle("Legend")
+        legend.attemptSetSceneRect(QRectF(120, 20, 80, 80))
+        legend.setFrameEnabled(True)
+        legend.setFrameStrokeWidth(QgsLayoutMeasurement(2))
+        legend.setBackgroundColor(QColor(200, 200, 200))
+        legend.setTitle('')
+        legend.setLegendFilterByMapEnabled(True)
+        legend.setSymbolWidth(20)
+        legend.setSymbolHeight(10)
+
+        text_format = QgsTextFormat()
+        text_format.setFont(QgsFontUtils.getStandardTestFont("Bold"))
+        text_format.setSize(16)
+
+        for legend_item in [QgsLegendStyle.Title, QgsLegendStyle.Group, QgsLegendStyle.Subgroup,
+                            QgsLegendStyle.Symbol, QgsLegendStyle.SymbolLabel]:
+            style = legend.style(legend_item)
+            style.setTextFormat(text_format)
+            legend.setStyle(legend_item, style)
+
+        # disable auto resizing
+        legend.setResizeToContents(False)
+
+        layout.addLayoutItem(legend)
+        legend.setLinkedMap(map)
+
+        map.setExtent(QgsRectangle(-100.3127, 35.7607, -98.5259, 36.5145))
+
+        checker = QgsLayoutChecker(
+            'composer_legend_geomgenerator_line', layout)
+        checker.setControlPathPrefix("composer_legend")
+        result, message = checker.testLayout()
+        TestQgsLayoutItemLegend.report += checker.report()
+        self.assertTrue(result, message)
+
+        QgsProject.instance().removeMapLayers([line_layer.id()])
+
 
 if __name__ == '__main__':
     unittest.main()