Add blend mode option for features, allows blending to be used betwee…

…n features in a layer
qgis · May 13, 2013 · 63ee006 · 63ee006
1 parent 226c524
commit 63ee006
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Showing 6 changed files with 105 additions and 19 deletions.
diff --git a/src/core/composer/qgscomposermap.cpp b/src/core/composer/qgscomposermap.cpp
@@ -655,10 +655,15 @@ bool QgsComposerMap::containsBlendModes() const
       {
         return true;
       }
-      // if vector layer and has labels, check label blend modes
+      // if vector layer, check labels and feature blend mode
       QgsVectorLayer* currentVectorLayer = qobject_cast<QgsVectorLayer *>( currentLayer );
       if ( currentVectorLayer )
       {
+        if ( currentVectorLayer->featureBlendMode() != QPainter::CompositionMode_SourceOver )
+        {
+          return true;
+        }
+        // check label blend modes
         if ( lbl->willUseLayer( currentVectorLayer ) )
         {
           // Check all label blending properties

diff --git a/src/core/qgsmaprenderer.cpp b/src/core/qgsmaprenderer.cpp
@@ -518,20 +518,29 @@ void QgsMapRenderer::render( QPainter* painter, double* forceWidthScale )
       // before compositing this on the map. This effectively flattens the layer and prevents
       // blending occuring between objects on the layer
       // (this is not required for raster layers or when layer caching is enabled, since that has the same effect)
-      if (( mRenderContext.useAdvancedEffects() ) && ( ml->blendMode()  != QPainter::CompositionMode_SourceOver ) &&
-          ( ml->type() != QgsMapLayer::RasterLayer ) &&
-          ( split || !mySettings.value( "/qgis/enable_render_caching", false ).toBool() ) )
+      bool flattenedLayer = false;
+      if (( mRenderContext.useAdvancedEffects() ) && ( ml->type() == QgsMapLayer::VectorLayer ) )
       {
-        mypFlattenedImage = new QImage( mRenderContext.painter()->device()->width(),
-                                        mRenderContext.painter()->device()->height(), QImage::Format_ARGB32 );
-        mypFlattenedImage->fill( 0 );
-        QPainter * mypPainter = new QPainter( mypFlattenedImage );
-        if ( mySettings.value( "/qgis/enable_anti_aliasing", true ).toBool() )
+        QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
+        if (( vl->blendMode() != QPainter::CompositionMode_SourceOver && ( split || !mySettings.value( "/qgis/enable_render_caching", false ).toBool() ) )
+            || ( vl->featureBlendMode() != QPainter::CompositionMode_SourceOver ) )
+
         {
-          mypPainter->setRenderHint( QPainter::Antialiasing );
+          flattenedLayer = true;
+          mypFlattenedImage = new QImage( mRenderContext.painter()->device()->width(),
+                                          mRenderContext.painter()->device()->height(), QImage::Format_ARGB32 );
+          mypFlattenedImage->fill( 0 );
+          QPainter * mypPainter = new QPainter( mypFlattenedImage );
+          if ( mySettings.value( "/qgis/enable_anti_aliasing", true ).toBool() )
+          {
+            mypPainter->setRenderHint( QPainter::Antialiasing );
+          }
+          mypPainter->scale( rasterScaleFactor,  rasterScaleFactor );
+          mRenderContext.setPainter( mypPainter );
+
+          // set the painter to the feature blend mode
+          mypPainter->setCompositionMode( vl->featureBlendMode() );
         }
-        mypPainter->scale( rasterScaleFactor,  rasterScaleFactor );
-        mRenderContext.setPainter( mypPainter );
       }
 
       if ( scaleRaster )
@@ -584,9 +593,7 @@ void QgsMapRenderer::render( QPainter* painter, double* forceWidthScale )
       }
 
       // If we flattened this layer for alternate blend modes, composite it now
-      if (( mRenderContext.useAdvancedEffects() ) && ( ml->blendMode()  != QPainter::CompositionMode_SourceOver ) &&
-          ( ml->type() != QgsMapLayer::RasterLayer ) &&
-          ( split || !mySettings.value( "/qgis/enable_render_caching", false ).toBool() ) )
+      if ( flattenedLayer )
       {
         delete mRenderContext.painter();
         mRenderContext.setPainter( mypContextPainter );

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
@@ -122,6 +122,7 @@ QgsVectorLayer::QgsVectorLayer( QString vectorLayerPath,
     , mRendererV2( NULL )
     , mLabel( 0 )
     , mLabelOn( false )
+    , mFeatureBlendMode( QPainter::CompositionMode_SourceOver ) // Default to normal feature blending
     , mVertexMarkerOnlyForSelection( false )
     , mCache( new QgsGeometryCache( this ) )
     , mEditBuffer( 0 )
@@ -1759,6 +1760,14 @@ bool QgsVectorLayer::readSymbology( const QDomNode& node, QString& errorMessage
       setBlendMode( QgsMapRenderer::getCompositionMode(( QgsMapRenderer::BlendMode ) e.text().toInt() ) );
     }
 
+    // get and set the feature blend mode if it exists
+    QDomNode featureBlendModeNode = node.namedItem( "featureBlendMode" );
+    if ( !featureBlendModeNode.isNull() )
+    {
+      QDomElement e = featureBlendModeNode.toElement();
+      setFeatureBlendMode( QgsMapRenderer::getCompositionMode(( QgsMapRenderer::BlendMode ) e.text().toInt() ) );
+    }
+
     // use scale dependent visibility flag
     QDomElement e = node.toElement();
     mLabel->setScaleBasedVisibility( e.attribute( "scaleBasedLabelVisibilityFlag", "0" ) == "1" );
@@ -2084,6 +2093,12 @@ bool QgsVectorLayer::writeSymbology( QDomNode& node, QDomDocument& doc, QString&
     blendModeElem.appendChild( blendModeText );
     node.appendChild( blendModeElem );
 
+    // add the feature blend mode field
+    QDomElement featureBlendModeElem  = doc.createElement( "featureBlendMode" );
+    QDomText featureBlendModeText = doc.createTextNode( QString::number( QgsMapRenderer::getBlendModeEnum( featureBlendMode() ) ) );
+    featureBlendModeElem.appendChild( featureBlendModeText );
+    node.appendChild( featureBlendModeElem );
+
     // add the display field
     QDomElement dField  = doc.createElement( "displayfield" );
     QDomText dFieldText = doc.createTextNode( displayField() );
@@ -3340,6 +3355,18 @@ QVariant QgsVectorLayer::maximumValue( int index )
   return QVariant();
 }
 
+/** Write blend mode for features */
+void QgsVectorLayer::setFeatureBlendMode( const QPainter::CompositionMode featureBlendMode )
+{
+  mFeatureBlendMode = featureBlendMode;
+}
+
+/** Read blend mode for layer */
+QPainter::CompositionMode QgsVectorLayer::featureBlendMode() const
+{
+  return mFeatureBlendMode;
+}
+
 void QgsVectorLayer::stopRendererV2( QgsRenderContext& rendererContext, QgsSingleSymbolRendererV2* selRenderer )
 {
   mRendererV2->stopRender( rendererContext );

diff --git a/src/core/qgsvectorlayer.h b/src/core/qgsvectorlayer.h
@@ -1226,6 +1226,15 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
       @note added in 1.7*/
     QVariant maximumValue( int index );
 
+    /* Set the blending mode used for rendering each feature
+     * @note added in 2.0
+     */
+    void setFeatureBlendMode( const QPainter::CompositionMode blendMode );
+    /* Returns the current blending mode for features
+     * @note added in 2.0
+     */
+    QPainter::CompositionMode featureBlendMode() const;
+
   public slots:
     /**
      * Select feature by its ID
@@ -1480,6 +1489,9 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
     /** Display labels */
     bool mLabelOn;
 
+    /** Blend mode for features */
+    QPainter::CompositionMode mFeatureBlendMode;
+
     /**The current type of editing marker*/
     QgsVectorLayer::VertexMarkerType mCurrentVertexMarkerType;
 

diff --git a/src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp b/src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp
@@ -89,6 +89,9 @@ QgsRendererV2PropertiesDialog::QgsRendererV2PropertiesDialog( QgsVectorLayer* la
   // Blend mode
   mBlendModeComboBox->setBlendMode( mLayer->blendMode() );
 
+  // Feature blend mode
+  mFeatureBlendComboBox->setBlendMode( mLayer->featureBlendMode() );
+
   QPixmap pix;
   QgsRendererV2Registry* reg = QgsRendererV2Registry::instance();
   QStringList renderers = reg->renderersList();
@@ -173,8 +176,9 @@ void QgsRendererV2PropertiesDialog::apply()
     mLayer->setRendererV2( renderer->clone() );
   }
 
-  // set the blend mode for the layer
+  // set the blend modes for the layer
   mLayer->setBlendMode( mBlendModeComboBox->blendMode() );
+  mLayer->setFeatureBlendMode( mFeatureBlendComboBox->blendMode() );
 }
 
 void QgsRendererV2PropertiesDialog::onOK()

diff --git a/src/ui/qgsrendererv2propsdialogbase.ui b/src/ui/qgsrendererv2propsdialogbase.ui
@@ -14,6 +14,31 @@
    <string>Renderer settings</string>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout_2">
+   <item>
+    <widget class="QgsCollapsibleGroupBox" name="groupBox">
+     <property name="title">
+      <string>Layer rendering</string>
+     </property>
+     <property name="collapsed" stdset="0">
+      <bool>false</bool>
+     </property>
+     <property name="saveCollapsedState" stdset="0">
+      <bool>true</bool>
+     </property>     
+     <layout class="QHBoxLayout" name="horizontalLayout">
+      <item>
+       <widget class="QLabel" name="lblLayerBlend">
+        <property name="text">
+         <string>Layer blending mode</string>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <widget class="QgsBlendModeComboBox" name="mBlendModeComboBox"/>
+      </item>
+     </layout>
+    </widget>
+   </item>
    <item>
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>
@@ -33,14 +58,14 @@
       </spacer>
      </item>
      <item>
-      <widget class="QLabel" name="label_2">
+      <widget class="QLabel" name="lblFeatureBlend">
        <property name="text">
-        <string>Blending mode</string>
+        <string>Feature blending mode</string>
        </property>
       </widget>
      </item>
      <item>
-      <widget class="QgsBlendModeComboBox" name="mBlendModeComboBox"/>
+      <widget class="QgsBlendModeComboBox" name="mFeatureBlendComboBox"/>
      </item>
     </layout>
    </item>
@@ -89,6 +114,12 @@
    <extends>QComboBox</extends>
    <header>qgsblendmodecombobox.h</header>
   </customwidget>
+  <customwidget>
+   <class>QgsCollapsibleGroupBox</class>
+   <extends>QGroupBox</extends>
+   <header>qgscollapsiblegroupbox.h</header>
+   <container>1</container>
+  </customwidget>  
  </customwidgets>
  <tabstops>
   <tabstop>cboRenderers</tabstop>