enable/disable better stretch histogram action

git-svn-id: http://svn.osgeo.org/qgis/trunk@15714 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/app/qgisapp.cpp

@@ -6040,15 +6040,23 @@ void QgisApp::activateDeactivateLayerRelatedActions( QgsMapLayer* layer )
   else if ( layer->type() == QgsMapLayer::RasterLayer )
   {
     const QgsRasterLayer *rlayer = qobject_cast<const QgsRasterLayer *>( layer );
-    if ( rlayer->providerKey() == "wms" )
+    if ( rlayer->dataProvider()->dataType( 1 ) != QgsRasterDataProvider::ARGBDataType )
     {
-      mActionLocalHistogramStretch->setEnabled( false );
-      mActionFullHistogramStretch->setEnabled( false );
+      if ( rlayer->dataProvider()->capabilities() & QgsRasterDataProvider::Size )
+      {
+        mActionFullHistogramStretch->setEnabled( true );
+      }
+      else
+      {
+        // it would hang up reading the data for WMS for example
+        mActionFullHistogramStretch->setEnabled( false );
+      }
+      mActionLocalHistogramStretch->setEnabled( true );
     }
     else
     {
-      mActionLocalHistogramStretch->setEnabled( true );
-      mActionFullHistogramStretch->setEnabled( true );
+      mActionLocalHistogramStretch->setEnabled( false );
+      mActionFullHistogramStretch->setEnabled( false );
     }
     mActionLayerSubsetString->setEnabled( false );
     mActionSelect->setEnabled( false );

src/providers/gdal/qgsgdalprovider.cpp

@@ -1126,8 +1126,14 @@ int QgsGdalProvider::capabilities() const
                    | QgsRasterDataProvider::ExactResolution
                    | QgsRasterDataProvider::EstimatedMinimumMaximum
                    | QgsRasterDataProvider::BuildPyramids
-                   | QgsRasterDataProvider::Histogram
-                   | QgsRasterDataProvider::Size;
+                   | QgsRasterDataProvider::Histogram;
+  GDALDriverH myDriver = GDALGetDatasetDriver( mGdalDataset );
+  QString name = GDALGetDriverShortName( myDriver );
+  QgsDebugMsg( "driver short name = " + name );
+  if ( name != "WMS" )
+  {
+    capability |= QgsRasterDataProvider::Size;
+  }
   return capability;
 }