src/core/qgsvectorlayer.cpp

@@ -136,6 +136,7 @@ QgsVectorLayer::QgsVectorLayer( QString vectorLayerPath,
     , mDiagramRenderer( 0 )
     , mDiagramLayerSettings( 0 )
     , mValidExtent( false )
+    , mLazyExtent( true )
     , mSymbolFeatureCounted( false )
     , mCurrentRendererContext( 0 )
 
@@ -1179,15 +1180,30 @@ void QgsVectorLayer::setExtent( const QgsRectangle &r )
 
 QgsRectangle QgsVectorLayer::extent()
 {
-  if ( mValidExtent )
-    return QgsMapLayer::extent();
-
   QgsRectangle rect;
   rect.setMinimal();
 
   if ( !hasGeometryType() )
     return rect;
 
+  if ( !mValidExtent && mLazyExtent && mDataProvider )
+  {
+    // get the extent
+    QgsRectangle mbr = mDataProvider->extent();
+
+    // show the extent
+    QString s = mbr.toString();
+
+    QgsDebugMsg( "Extent of layer: " +  s );
+    // store the extent
+    setExtent( mbr );
+
+    mLazyExtent = false;
+  }
+
+  if( mValidExtent )
+    return QgsMapLayer::extent();
+
   if ( !mDataProvider )
   {
     QgsDebugMsg( "invoked with null mDataProvider" );
@@ -1704,17 +1720,6 @@ bool QgsVectorLayer::setDataProvider( QString const & provider )
       // TODO: Check if the provider has the capability to send fullExtentCalculated
       connect( mDataProvider, SIGNAL( fullExtentCalculated() ), this, SLOT( updateExtents() ) );
 
-#if 0 // allow lazy calculation of extents and give the creator of the vector layer a chance to 'manually' setExtent
-      // get the extent
-      QgsRectangle mbr = mDataProvider->extent();
-
-      // show the extent
-      QString s = mbr.toString();
-      QgsDebugMsg( "Extent of layer: " +  s );
-      // store the extent
-      setExtent( mbr );
-#endif
-
       // get and store the feature type
       mWkbType = mDataProvider->geometryType();
 

src/core/qgsvectorlayer.h

@@ -1756,6 +1756,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
     QgsDiagramLayerSettings *mDiagramLayerSettings;
 
     bool mValidExtent;
+    bool mLazyExtent;
 
     // Features in renderer classes counted
     bool mSymbolFeatureCounted;

src/core/raster/qgsrasterdataprovider.h

@@ -66,7 +66,13 @@ class CORE_EXPORT QgsRasterDataProvider : public QgsDataProvider, public QgsRast
     /* It makes no sense to set input on provider */
     bool setInput( QgsRasterInterface* input ) { Q_UNUSED( input ); return false; }
 
-    /** \brief   Renders the layer as an image */
+    /** \brief   Renders the layer as an image
+	\note When render caching (/qgis/enable_render_caching) is on the wms
+	      provider doesn't wait for the reply of the getmap request or all
+	      tiles replies and can return incomplete images.
+	      Temporarily disable render caching if you require the complete
+	      wms image in the first call.
+      */
     virtual QImage* draw( const QgsRectangle & viewExtent, int pixelWidth, int pixelHeight ) = 0;
 
     /** Get the extent of the data source.