[ui] Disable fill color for stroke-only ellipse symbols

python/core/auto_generated/symbology/qgsellipsesymbollayer.sip.in

@@ -51,7 +51,7 @@ Creates the symbol layer
     void setSymbolName( const QString &name );
     QString symbolName() const;
 
-    bool shapeIsFilled( const QString &symbolName ) const;
+    static bool shapeIsFilled( const QString &symbolName );
 %Docstring
 Returns ``True`` if a shape has a fill.
 

src/core/symbology/qgsellipsesymbollayer.cpp

@@ -669,7 +669,7 @@ void QgsEllipseSymbolLayer::preparePath( const QString &symbolName, QgsSymbolRen
   }
 }
 
-bool QgsEllipseSymbolLayer::shapeIsFilled( const QString &symbolName ) const
+bool QgsEllipseSymbolLayer::shapeIsFilled( const QString &symbolName )
 {
   return symbolName == QLatin1String( "cross" ) || symbolName == QLatin1String( "arrow" ) || symbolName == QLatin1String( "half_arc" ) ? false : true;
 }

src/core/symbology/qgsellipsesymbollayer.h

@@ -58,7 +58,7 @@ class CORE_EXPORT QgsEllipseSymbolLayer: public QgsMarkerSymbolLayer
      * \returns TRUE if shape uses a fill, or FALSE if shape uses lines only
      * \since QGIS 3.20
      */
-    bool shapeIsFilled( const QString &symbolName ) const;
+    static bool shapeIsFilled( const QString &symbolName );
 
     void setSize( double size ) override;
 

src/gui/symbology/qgsellipsesymbollayerwidget.cpp

@@ -121,6 +121,7 @@ void QgsEllipseSymbolLayerWidget::setSymbolLayer( QgsSymbolLayer *layer )
   {
     mShapeListWidget->setCurrentItem( symbolItemList.at( 0 ) );
   }
+  btnChangeColorFill->setEnabled( QgsEllipseSymbolLayer::shapeIsFilled( mLayer->symbolName() ) );
 
   //set combo entries to current values
   blockComboSignals( true );
@@ -170,6 +171,7 @@ void QgsEllipseSymbolLayerWidget::mShapeListWidget_itemSelectionChanged()
     if ( item )
     {
       mLayer->setSymbolName( item->data( Qt::UserRole ).toString() );
+      btnChangeColorFill->setEnabled( QgsEllipseSymbolLayer::shapeIsFilled( mLayer->symbolName() ) );
       emit changed();
     }
   }