Ensure correct symbol geometry type is used for more preview icons

qgis · Nov 1, 2021 · 252b1e9 · 252b1e9
1 parent b2cac9b
commit 252b1e9
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Showing 4 changed files with 22 additions and 4 deletions.
diff --git a/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in b/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in
@@ -250,14 +250,15 @@ Returns a pixmap preview for a color ramp.
 .. seealso:: :py:func:`symbolPreviewIcon`
 %End
 
-    static QPicture symbolLayerPreviewPicture( const QgsSymbolLayer *layer, QgsUnitTypes::RenderUnit units, QSize size, const QgsMapUnitScale &scale = QgsMapUnitScale() );
+    static QPicture symbolLayerPreviewPicture( const QgsSymbolLayer *layer, QgsUnitTypes::RenderUnit units, QSize size, const QgsMapUnitScale &scale = QgsMapUnitScale(), Qgis::SymbolType parentSymbolType = Qgis::SymbolType::Hybrid );
 %Docstring
 Draws a symbol layer preview to a QPicture
 
 :param layer: symbol layer to draw
 :param units: size units
 :param size: target size of preview picture
 :param scale: map unit scale for preview
+:param parentSymbolType: since QGIS 3.22, can be used to specify the parent symbol type so that geometry generator preview icons are correctly calculated
 
 :return: QPicture containing symbol layer preview
 

diff --git a/src/core/symbology/qgssymbollayerutils.cpp b/src/core/symbology/qgssymbollayerutils.cpp
@@ -842,7 +842,7 @@ double QgsSymbolLayerUtils::estimateMaxSymbolBleed( QgsSymbol *symbol, const Qgs
   return maxBleed;
 }
 
-QPicture QgsSymbolLayerUtils::symbolLayerPreviewPicture( const QgsSymbolLayer *layer, QgsUnitTypes::RenderUnit units, QSize size, const QgsMapUnitScale & )
+QPicture QgsSymbolLayerUtils::symbolLayerPreviewPicture( const QgsSymbolLayer *layer, QgsUnitTypes::RenderUnit units, QSize size, const QgsMapUnitScale &, Qgis::SymbolType parentSymbolType )
 {
   QPicture picture;
   QPainter painter;
@@ -852,6 +852,22 @@ QPicture QgsSymbolLayerUtils::symbolLayerPreviewPicture( const QgsSymbolLayer *l
   renderContext.setForceVectorOutput( true );
   renderContext.setFlag( Qgis::RenderContextFlag::RenderSymbolPreview, true );
   QgsSymbolRenderContext symbolContext( renderContext, units, 1.0, false, Qgis::SymbolRenderHints(), nullptr );
+
+  switch ( parentSymbolType )
+  {
+    case Qgis::SymbolType::Marker:
+      symbolContext.setOriginalGeometryType( QgsWkbTypes::PointGeometry );
+      break;
+    case Qgis::SymbolType::Line:
+      symbolContext.setOriginalGeometryType( QgsWkbTypes::LineGeometry );
+      break;
+    case Qgis::SymbolType::Fill:
+      symbolContext.setOriginalGeometryType( QgsWkbTypes::PolygonGeometry );
+      break;
+    case Qgis::SymbolType::Hybrid:
+      break;
+  }
+
   std::unique_ptr< QgsSymbolLayer > layerClone( layer->clone() );
   layerClone->drawPreviewIcon( symbolContext, size );
   painter.end();

diff --git a/src/core/symbology/qgssymbollayerutils.h b/src/core/symbology/qgssymbollayerutils.h
@@ -248,11 +248,12 @@ class CORE_EXPORT QgsSymbolLayerUtils
      * \param units size units
      * \param size target size of preview picture
      * \param scale map unit scale for preview
+     * \param parentSymbolType since QGIS 3.22, can be used to specify the parent symbol type so that geometry generator preview icons are correctly calculated
      * \returns QPicture containing symbol layer preview
      * \see symbolLayerPreviewIcon()
      * \since QGIS 2.9
      */
-    static QPicture symbolLayerPreviewPicture( const QgsSymbolLayer *layer, QgsUnitTypes::RenderUnit units, QSize size, const QgsMapUnitScale &scale = QgsMapUnitScale() );
+    static QPicture symbolLayerPreviewPicture( const QgsSymbolLayer *layer, QgsUnitTypes::RenderUnit units, QSize size, const QgsMapUnitScale &scale = QgsMapUnitScale(), Qgis::SymbolType parentSymbolType = Qgis::SymbolType::Hybrid );
 
     /**
      * Draws a symbol layer preview to an icon.

diff --git a/src/gui/symbology/qgslayerpropertieswidget.cpp b/src/gui/symbology/qgslayerpropertieswidget.cpp
@@ -345,7 +345,7 @@ void QgsLayerPropertiesWidget::emitSignalChanged()
     mLayer->paintEffect()->setEnabled( false );
     paintEffectToggled = true;
   }
-  mEffectWidget->setPreviewPicture( QgsSymbolLayerUtils::symbolLayerPreviewPicture( mLayer, QgsUnitTypes::RenderMillimeters, QSize( 60, 60 ) ) );
+  mEffectWidget->setPreviewPicture( QgsSymbolLayerUtils::symbolLayerPreviewPicture( mLayer, QgsUnitTypes::RenderMillimeters, QSize( 60, 60 ), QgsMapUnitScale(), mSymbol ? mSymbol->type() : Qgis::SymbolType::Hybrid ) );
   if ( paintEffectToggled )
   {
     mLayer->paintEffect()->setEnabled( true );