Raster layer properties : use/save default pyramid resampling method

Currently when you build raster pyramids from the Pyramids tab in raster layer
properties, the default method proposed is the first one in the combobox, i.e. nearest
neighbour. This is generally a poor choice for quality.
This changeset uses the settings gdal/driverOptions/_pyramids/resampling already
used by the Options dialog to select the resampling method (and AVERAGE if not yet
defined), and it saves the user choice when generating them.

src/app/qgsrasterlayerproperties.cpp

@@ -183,6 +183,16 @@ QgsRasterLayerProperties::QgsRasterLayerProperties( QgsMapLayer* lyr, QgsMapCanv
     {
       cboResamplingMethod->addItem( method.second, method.first );
     }
+
+    // keep it in sync with qgsrasterpyramidsoptionwidget.cpp
+    QString prefix = provider->name() + "/driverOptions/_pyramids/";
+    QSettings mySettings;
+    QString defaultMethod = mySettings.value( prefix + "resampling", "AVERAGE" ).toString();
+    int idx = cboResamplingMethod->findData( defaultMethod );
+    if ( idx >= 0 )
+      cboResamplingMethod->setCurrentIndex( idx );
+
+
     // build pyramid list
     QList< QgsRasterPyramid > myPyramidList = provider->buildPyramidList();
     QList< QgsRasterPyramid >::iterator myRasterPyramidIterator;
@@ -988,6 +998,13 @@ void QgsRasterLayerProperties::on_buttonBuildPyramids_clicked()
     //mark to be pyramided
     myPyramidList[myCounterInt].build = myItem->isSelected() || myPyramidList[myCounterInt].exists;
   }
+
+  // keep it in sync with qgsrasterpyramidsoptionwidget.cpp
+  QString prefix = provider->name() + "/driverOptions/_pyramids/";
+  QSettings mySettings;
+  QString resamplingMethod( cboResamplingMethod->itemData( cboResamplingMethod->currentIndex() ).toString() );
+  mySettings.setValue( prefix + "resampling", resamplingMethod );
+
   //
   // Ask raster layer to build the pyramids
   //
@@ -996,7 +1013,7 @@ void QgsRasterLayerProperties::on_buttonBuildPyramids_clicked()
   QApplication::setOverrideCursor( Qt::WaitCursor );
   QString res = provider->buildPyramids(
                   myPyramidList,
-                  cboResamplingMethod->itemData( cboResamplingMethod->currentIndex() ).toString(),
+                  resamplingMethod,
                   ( QgsRaster::RasterPyramidsFormat ) cbxPyramidsFormat->currentIndex() );
   QApplication::restoreOverrideCursor();
   mPyramidProgress->setValue( 0 );

src/gui/qgsrasterpyramidsoptionswidget.cpp

@@ -52,8 +52,8 @@ void QgsRasterPyramidsOptionsWidget::updateUi()
   QString prefix = mProvider + "/driverOptions/_pyramids/";
   QString tmpStr;
 
-  // cbxPyramidsInternal->setChecked( mySettings.value( prefix + "internal", false ).toBool() );
-  tmpStr = mySettings.value( prefix + "format", "gtiff" ).toString();
+  // keep it in sync with qgsrasterlayerproperties.cpp
+  tmpStr = mySettings.value( prefix + "format", "external" ).toString();
   if ( tmpStr == "internal" )
     cbxPyramidsFormat->setCurrentIndex( 1 );
   else if ( tmpStr == "external_erdas" )
@@ -68,8 +68,9 @@ void QgsRasterPyramidsOptionsWidget::updateUi()
   {
     cboResamplingMethod->addItem( method.second, method.first );
   }
-  cboResamplingMethod->setCurrentIndex( cboResamplingMethod->findData(
-                                          mySettings.value( prefix + "resampling", "AVERAGE" ).toString() ) );
+  QString defaultMethod = mySettings.value( prefix + "resampling", "AVERAGE" ).toString();
+  int idx = cboResamplingMethod->findData( defaultMethod );
+  cboResamplingMethod->setCurrentIndex( idx );
 
   // validate string, only space-separated positive integers are allowed
   lePyramidsLevels->setEnabled( cbxPyramidsLevelsCustom->isChecked() );