Optionally pass vector layer pointer to rendercontext

src/core/symbology-ng/qgssinglesymbolrendererv2.cpp

@@ -72,7 +72,7 @@ void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const Qg
   mRotationFieldIdx  = mRotationField.isEmpty()  ? -1 : vlayer->fieldNameIndex( mRotationField );
   mSizeScaleFieldIdx = mSizeScaleField.isEmpty() ? -1 : vlayer->fieldNameIndex( mSizeScaleField );
 
-  mSymbol->startRender( context );
+  mSymbol->startRender( context, vlayer );
 
   if ( mRotationFieldIdx != -1 || mSizeScaleFieldIdx != -1 )
   {
@@ -86,7 +86,7 @@ void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const Qg
       hints |= QgsSymbolV2::DataDefinedSizeScale;
     mTempSymbol->setRenderHints( hints );
 
-    mTempSymbol->startRender( context );
+    mTempSymbol->startRender( context, vlayer );
 
     if ( mSymbol->type() == QgsSymbolV2::Marker )
     {

src/core/symbology-ng/qgssymbolv2.cpp

@@ -134,9 +134,10 @@ bool QgsSymbolV2::changeSymbolLayer( int index, QgsSymbolLayerV2* layer )
 }
 
 
-void QgsSymbolV2::startRender( QgsRenderContext& context )
+void QgsSymbolV2::startRender( QgsRenderContext& context, const QgsVectorLayer* layer )
 {
   QgsSymbolV2RenderContext symbolContext( context, mOutputUnit, mAlpha, false, mRenderHints );
+  symbolContext.setLayer( layer );
   for ( QgsSymbolLayerV2List::iterator it = mLayers.begin(); it != mLayers.end(); ++it )
     ( *it )->startRender( symbolContext );
 }
@@ -282,7 +283,7 @@ QSet<QString> QgsSymbolV2::usedAttributes() const
 ////////////////////
 
 QgsSymbolV2RenderContext::QgsSymbolV2RenderContext( QgsRenderContext& c, QgsSymbolV2::OutputUnit u, qreal alpha, bool selected, int renderHints, const QgsFeature* f )
-    : mRenderContext( c ), mOutputUnit( u ), mAlpha( alpha ), mSelected( selected ), mRenderHints( renderHints ), mFeature( f )
+    : mRenderContext( c ), mOutputUnit( u ), mAlpha( alpha ), mSelected( selected ), mRenderHints( renderHints ), mFeature( f ), mLayer( 0 )
 {
 
 }

src/core/symbology-ng/qgssymbolv2.h

@@ -17,6 +17,7 @@ class QPolygonF;
 class QgsFeature;
 class QgsSymbolLayerV2;
 class QgsRenderContext;
+class QgsVectorLayer;
 
 typedef QMap<QString, QString> QgsStringMap;
 typedef QList<QgsSymbolLayerV2*> QgsSymbolLayerV2List;
@@ -74,7 +75,7 @@ class CORE_EXPORT QgsSymbolV2
     bool changeSymbolLayer( int index, QgsSymbolLayerV2* layer );
 
 
-    void startRender( QgsRenderContext& context );
+    void startRender( QgsRenderContext& context, const QgsVectorLayer* layer = 0 );
     void stopRender( QgsRenderContext& context );
 
     void setColor( const QColor& color );
@@ -150,6 +151,9 @@ class CORE_EXPORT QgsSymbolV2RenderContext
     void setFeature( const QgsFeature* f ) { mFeature = f; }
     const QgsFeature* feature() const { return mFeature; }
 
+    void setLayer( const QgsVectorLayer* layer ) { mLayer = layer; }
+    const QgsVectorLayer* layer() const { return mLayer; }
+
     // Color used for selections
     static QColor selectionColor();
 
@@ -166,6 +170,7 @@ class CORE_EXPORT QgsSymbolV2RenderContext
     bool mSelected;
     int mRenderHints;
     const QgsFeature* mFeature; //current feature
+    const QgsVectorLayer* mLayer; //current vectorlayer
 };
 
 

src/core/symbology-ng/qgsvectorfieldsymbollayer.cpp

@@ -16,9 +16,10 @@
  ***************************************************************************/
 
 #include "qgsvectorfieldsymbollayer.h"
+#include "qgsvectorlayer.h"
 
-QgsVectorFieldSymbolLayer::QgsVectorFieldSymbolLayer(): mXAttribute( -1 ), mYAttribute( -1 ), mScale( 1.0 ),
-    mVectorFieldType( Cartesian ), mAngleOrientation( ClockwiseFromNorth ), mAngleUnits( Degrees )
+QgsVectorFieldSymbolLayer::QgsVectorFieldSymbolLayer(): mXAttribute( "" ), mYAttribute( "" ), mScale( 1.0 ),
+    mVectorFieldType( Cartesian ), mAngleOrientation( ClockwiseFromNorth ), mAngleUnits( Degrees ), mXIndex( -1 ), mYIndex( -1 )
 {
   setSubSymbol( new QgsLineSymbolV2() );
 }
@@ -32,11 +33,11 @@ QgsSymbolLayerV2* QgsVectorFieldSymbolLayer::create( const QgsStringMap& propert
   QgsVectorFieldSymbolLayer* symbolLayer = new QgsVectorFieldSymbolLayer();
   if ( properties.contains( "x_attribute" ) )
   {
-    symbolLayer->setXAttribute( properties["x_attribute"].toInt() );
+    symbolLayer->setXAttribute( properties["x_attribute"] );
   }
   if ( properties.contains( "y_attribute" ) )
   {
-    symbolLayer->setYAttribute( properties["y_attribute"].toInt() );
+    symbolLayer->setYAttribute( properties["y_attribute"] );
   }
   if ( properties.contains( "scale" ) )
   {
@@ -69,7 +70,52 @@ bool QgsVectorFieldSymbolLayer::setSubSymbol( QgsSymbolV2* symbol )
 
 void QgsVectorFieldSymbolLayer::renderPoint( const QPointF& point, QgsSymbolV2RenderContext& context )
 {
-  //soon...
+  if ( !mLineSymbol )
+  {
+    return;
+  }
+
+  const QgsFeature* f = context.feature();
+  if ( !f )
+  {
+    //preview
+    QPolygonF line;
+    line << QPointF( 0, 50 );
+    line << QPointF( 100, 50 );
+    mLineSymbol->renderPolyline( line, 0, context.renderContext() );
+  }
+
+  double xComponent = 0;
+  double yComponent = 0;
+
+  double xVal = 0;
+  if ( mXIndex != -1 )
+  {
+    xVal = f->attributeMap()[mXIndex].toDouble();
+  }
+  double yVal = 0;
+  if ( mYIndex != -1 )
+  {
+    yVal = f->attributeMap()[mYIndex].toDouble();
+  }
+
+  switch ( mVectorFieldType )
+  {
+    case Cartesian:
+      xComponent = context.outputLineWidth( xVal );
+      yComponent = context.outputLineWidth( yVal );
+      break;
+    default:
+      break;
+  }
+
+  xComponent *= mScale;
+  yComponent *= mScale;
+
+  QPolygonF line;
+  line << point;
+  line << QPointF( point.x() + xComponent, point.y() - yComponent );
+  mLineSymbol->renderPolyline( line, f, context.renderContext() );
 }
 
 void QgsVectorFieldSymbolLayer::startRender( QgsSymbolV2RenderContext& context )
@@ -78,6 +124,18 @@ void QgsVectorFieldSymbolLayer::startRender( QgsSymbolV2RenderContext& context )
   {
     mLineSymbol->startRender( context.renderContext() );
   }
+
+  const QgsVectorLayer* layer = context.layer();
+  if ( layer )
+  {
+    mXIndex = layer->fieldNameIndex( mXAttribute );
+    mYIndex = layer->fieldNameIndex( mYAttribute );
+  }
+  else
+  {
+    mXIndex = -1;
+    mYIndex = -1;
+  }
 }
 
 void QgsVectorFieldSymbolLayer::stopRender( QgsSymbolV2RenderContext& context )
@@ -90,17 +148,44 @@ void QgsVectorFieldSymbolLayer::stopRender( QgsSymbolV2RenderContext& context )
 
 QgsSymbolLayerV2* QgsVectorFieldSymbolLayer::clone() const
 {
-  return QgsVectorFieldSymbolLayer::create( properties() );
+  QgsSymbolLayerV2* clonedLayer = QgsVectorFieldSymbolLayer::create( properties() );
+  if ( mLineSymbol )
+  {
+    clonedLayer->setSubSymbol( mLineSymbol->clone() );
+  }
+  return clonedLayer;
 }
 
 QgsStringMap QgsVectorFieldSymbolLayer::properties() const
 {
   QgsStringMap properties;
-  properties["x_attribute"] = QString::number( mXAttribute );
-  properties["y_attribute"] = QString::number( mYAttribute );
+  properties["x_attribute"] = mXAttribute;
+  properties["y_attribute"] = mYAttribute;
   properties["scale"] = QString::number( mScale );
   properties["vector_field_type"] = QString::number( mVectorFieldType );
   properties["angle_orientation"] = QString::number( mAngleOrientation );
   properties["angle_units"] = QString::number( mAngleUnits );
   return properties;
 }
+
+void QgsVectorFieldSymbolLayer::drawPreviewIcon( QgsSymbolV2RenderContext& context, QSize size )
+{
+  if ( mLineSymbol )
+  {
+    mLineSymbol->drawPreviewIcon( context.renderContext().painter(), size );
+  }
+}
+
+QSet<QString> QgsVectorFieldSymbolLayer::usedAttributes() const
+{
+  QSet<QString> attributes;
+  if ( !mXAttribute.isEmpty() )
+  {
+    attributes.insert( mXAttribute );
+  }
+  if ( !mYAttribute.isEmpty() )
+  {
+    attributes.insert( mYAttribute );
+  }
+  return attributes;
+}

src/core/symbology-ng/qgsvectorfieldsymbollayer.h

@@ -60,11 +60,15 @@ class QgsVectorFieldSymbolLayer: public QgsMarkerSymbolLayerV2
     QgsSymbolLayerV2* clone() const;
     QgsStringMap properties() const;
 
+    void drawPreviewIcon( QgsSymbolV2RenderContext& context, QSize size );
+
+    QSet<QString> usedAttributes() const;
+
     //setters and getters
-    void setXAttribute( int attribute ) { mXAttribute = attribute; }
-    int xAttribute() const { return mXAttribute; }
-    void setYAttribute( int attribute ) { mYAttribute = attribute; }
-    int yAttribute() const { return mYAttribute; }
+    void setXAttribute( const QString& attribute ) { mXAttribute = attribute; }
+    QString xAttribute() const { return mXAttribute; }
+    void setYAttribute( const QString& attribute ) { mYAttribute = attribute; }
+    QString yAttribute() const { return mYAttribute; }
     void setScale( double s ) { mScale = s; }
     double scale() const { return mScale; }
     void setVectorFieldType( VectorFieldType type ) { mVectorFieldType = type; }
@@ -75,14 +79,18 @@ class QgsVectorFieldSymbolLayer: public QgsMarkerSymbolLayerV2
     AngleUnits angleUnits() const { return mAngleUnits; }
 
   private:
-    int mXAttribute;
-    int mYAttribute;
+    QString mXAttribute;
+    QString mYAttribute;
     double mScale;
     VectorFieldType mVectorFieldType;
     AngleOrientation mAngleOrientation;
     AngleUnits mAngleUnits;
 
     QgsLineSymbolV2* mLineSymbol;
+
+    //Attribute indices are resolved in startRender method
+    int mXIndex;
+    int mYIndex;
 };
 
 #endif // QGSVECTORFIELDSYMBOLLAYER_H