-Prevent internal pyramids from being built on rasters with JPEG compression

-closes ticket #1357

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@9688 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: ersts

src/app/qgsrasterlayerproperties.cpp

@@ -1587,11 +1587,15 @@ void QgsRasterLayerProperties::on_buttonBuildPyramids_clicked()
       QMessageBox::warning( this, tr( "Building pyramids failed." ),
                             tr( "Building pyramid overviews is not supported on this type of raster." ) );
     }
+    else if ( res == "ERROR_JPEG_COMPRESSION" )
+    {
+      QMessageBox::warning( this, tr( "Building pyramids failed." ),
+                            tr( "Building internal pyramid overviews is not supported on raster layers with JPEG compression." ) );
+    }
     else if ( res == "ERROR_VIRTUAL" )
     {
       QMessageBox::warning( this, tr( "Building pyramids failed." ),
                             tr( "Building pyramid overviews is not supported on this type of raster." ) );
-      //TODO: should really read -- Building pyramid overviews is not supported for 'warped virtual dataset'. -- But in feature freeze, and translation requests have already gone out PJE20080912
     }
 
   }

src/core/raster/qgsrasterlayer.cpp

@@ -982,6 +982,11 @@ QString QgsRasterLayer::buildPyramids( RasterPyramidList const & theRasterPyrami
 
   if ( theTryInternalFlag )
   {
+    QString myCompressionType = QString( GDALGetMetadataItem(  mGdalDataset, "COMPRESSION", "IMAGE_STRUCTURE" ) );
+    if( "JPEG" == myCompressionType )
+    {
+      return "ERROR_JPEG_COMPRESSION";
+    }
     //close the gdal dataset and reopen it in read / write mode
     GDALClose( mGdalDataset );
     mGdalBaseDataset = GDALOpen( QFile::encodeName( mDataSource ).constData(), GA_Update );