Fix vector field symbol does not use subsymbol color (fix #15130)

(cherry-picked from e6034e9)

Author: nyalldawson

python/core/symbology-ng/qgsvectorfieldsymbollayer.sip

@@ -34,6 +34,9 @@ class QgsVectorFieldSymbolLayer : QgsMarkerSymbolLayerV2
     bool setSubSymbol( QgsSymbolV2* symbol /Transfer/ );
     QgsSymbolV2* subSymbol();
 
+    void setColor( const QColor& color );
+    virtual QColor color() const;
+
     void renderPoint( QPointF point, QgsSymbolV2RenderContext& context );
     void startRender( QgsSymbolV2RenderContext& context );
     void stopRender( QgsSymbolV2RenderContext& context );

src/core/symbology-ng/qgsvectorfieldsymbollayer.cpp

@@ -319,4 +319,17 @@ void QgsVectorFieldSymbolLayer::convertPolarToCartesian( double length, double a
   y = length * cos( angle );
 }
 
+void QgsVectorFieldSymbolLayer::setColor( const QColor& color )
+{
+  if ( mLineSymbol )
+    mLineSymbol->setColor( color );
+
+  mColor = color;
+}
+
+QColor QgsVectorFieldSymbolLayer::color() const
+{
+  return mLineSymbol ? mLineSymbol->color() : mColor;
+}
+
 

src/core/symbology-ng/qgsvectorfieldsymbollayer.h

@@ -54,6 +54,9 @@ class CORE_EXPORT QgsVectorFieldSymbolLayer: public QgsMarkerSymbolLayerV2
     bool setSubSymbol( QgsSymbolV2* symbol ) override;
     QgsSymbolV2* subSymbol() override { return mLineSymbol; }
 
+    void setColor( const QColor& color ) override;
+    virtual QColor color() const override;
+
     void renderPoint( QPointF point, QgsSymbolV2RenderContext& context ) override;
     void startRender( QgsSymbolV2RenderContext& context ) override;
     void stopRender( QgsSymbolV2RenderContext& context ) override;

tests/src/python/test_qgssymbollayerv2.py

@@ -730,5 +730,19 @@ def testQgsSvgMarkerSymbolLayerV2(self):
         mMessage = 'Expected "%s" got "%s"' % (mExpectedValue, mValue)
         assert mExpectedValue == mValue, mMessage
 
+    def testQgsVectorFieldSymbolLayer(self):
+        """
+        Test QgsVectorFieldSymbolLayer
+        """
+        # test colors, need to make sure colors are passed/retrieved from subsymbol
+        mSymbolLayer = QgsVectorFieldSymbolLayer.create()
+
+        mSymbolLayer.setColor(QColor(150, 50, 100))
+        self.assertEqual(mSymbolLayer.color(), QColor(150, 50, 100))
+        self.assertEqual(mSymbolLayer.subSymbol().color(), QColor(150, 50, 100))
+        mSymbolLayer.subSymbol().setColor(QColor(250, 150, 200))
+        self.assertEqual(mSymbolLayer.subSymbol().color(), QColor(250, 150, 200))
+        self.assertEqual(mSymbolLayer.color(), QColor(250, 150, 200))
+
 if __name__ == '__main__':
     unittest.main()