[FEATURE]: Show colormap items in legend

Author: mhugent

src/app/legend/qgslegendlayer.cpp

@@ -306,10 +306,22 @@ void QgsLegendLayer::vectorLayerSymbologyV2( QgsVectorLayer* layer )
 
 void QgsLegendLayer::rasterLayerSymbology( QgsRasterLayer* layer )
 {
+#if 0
   SymbologyList itemList;
   QPixmap legendpixmap = layer->legendAsPixmap( true ).scaled( 20, 20, Qt::KeepAspectRatio );
   itemList.append( qMakePair( QString(), legendpixmap ) );
 
+  changeSymbologySettings( layer, itemList );
+#endif //0
+  SymbologyList itemList;
+  QList< QPair< QString, QColor > > rasterItemList = layer->legendSymbologyItems();
+  QList< QPair< QString, QColor > >::const_iterator itemIt = rasterItemList.constBegin();
+  for(; itemIt != rasterItemList.constEnd(); ++itemIt )
+  {
+    QPixmap itemPixmap( treeWidget()->iconSize() );
+    itemPixmap.fill( itemIt->second );
+    itemList.append( qMakePair( itemIt->first, itemPixmap ) );
+  }
   changeSymbologySettings( layer, itemList );
 }
 

src/core/raster/qgsrasterlayer.cpp

@@ -1209,6 +1209,32 @@ QString QgsRasterLayer::lastErrorTitle()
   return mErrorCaption;
 }
 
+QList< QPair< QString, QColor > > QgsRasterLayer::legendSymbologyItems() const
+{
+  QList< QPair< QString, QColor > > symbolList;
+
+  switch ( mColorShadingAlgorithm )
+  {
+    case ColorRampShader:
+      {
+        const QgsColorRampShader* crShader = dynamic_cast<QgsColorRampShader*>( mRasterShader->rasterShaderFunction() );
+        if( crShader )
+        {
+          QList<QgsColorRampShader::ColorRampItem> shaderItems = crShader->colorRampItemList();
+          QList<QgsColorRampShader::ColorRampItem>::const_iterator itemIt = shaderItems.constBegin();
+          for(; itemIt != shaderItems.constEnd(); ++itemIt )
+          {
+            symbolList.push_back( qMakePair( itemIt->label, itemIt->color ) );
+          }
+        }
+        break;
+      }
+    default:
+      break;
+  }
+  return symbolList;
+}
+
 /**
  * This is an overloaded version of the legendAsPixmap( bool ) assumes false for the legend name flag.
  * @return a pixmap representing a legend image

src/core/raster/qgsrasterlayer.h

@@ -521,6 +521,10 @@ class CORE_EXPORT QgsRasterLayer : public QgsMapLayer
     /** \brief [ data provider interface ] If an operation returns 0 (e.g. draw()), this function returns the text of the error associated with the failure */
     QString lastErrorTitle();
 
+    /**Returns a list with classification items (Text and color)
+      @note this method was added in version 1.8*/
+    QList< QPair< QString, QColor > > legendSymbologyItems() const;
+
     /** \brief Get a legend image for this layer */
     QPixmap legendAsPixmap();