Merge topic 'gdal-active-layer' into master

8e5b524b Shapefiles: If active layer specified, load only it.

IO/GDAL/Testing/Cxx/TestGDALVectorReader.cxx

@@ -46,6 +46,20 @@ int TestGDALVectorReader(int argc, char** argv)
   vtkNew<vtkGDALVectorReader> reader;
   reader->SetFileName(vectorFileName);
   delete [] vectorFileName;
+
+  // Test layer information helpers
+  reader->UpdateInformation();
+  int nl = reader->GetNumberOfLayers();
+  for (int i = 0; i < nl; ++i)
+    {
+    reader->SetActiveLayer(i);
+    cout
+      << "Layer " << i
+      << " Type " << reader->GetActiveLayerType()
+      << " FeatureCount " << reader->GetActiveLayerFeatureCount()
+      << "\n";
+    }
+  reader->SetActiveLayer(0); // Read only layer 0, which is the only layer.
   reader->Update();
 
   // We need a renderer

IO/GDAL/vtkGDALVectorReader.cxx

@@ -298,6 +298,7 @@ vtkGDALVectorReader::vtkGDALVectorReader()
 {
   this->FileName = 0;
   this->Implementation = 0;
+  this->ActiveLayer = -1;
 
   this->SetNumberOfInputPorts( 0 );
 
@@ -408,13 +409,17 @@ int vtkGDALVectorReader::GetFeatureCount(int layerIndex)
 // -----------------------------------------------------------------------------
 int vtkGDALVectorReader::GetActiveLayerType()
 {
-  return this->GetLayerType(ActiveLayer);
+  return
+    this->ActiveLayer < 0 || this->ActiveLayer >= this->GetNumberOfLayers() ?
+    -1 : this->GetLayerType(this->ActiveLayer);
 }
 
 // -----------------------------------------------------------------------------
 int vtkGDALVectorReader::GetActiveLayerFeatureCount()
 {
-  return this->GetFeatureCount(ActiveLayer);
+  return
+    this->ActiveLayer < 0 || this->ActiveLayer >= this->GetNumberOfLayers() ?
+    0 : this->GetFeatureCount(this->ActiveLayer);
 }
 
 // -----------------------------------------------------------------------------
@@ -492,7 +497,13 @@ int vtkGDALVectorReader::RequestData( vtkInformation* request,
 
   vtkGDALVectorReader::Internal* p = this->Implementation;
 
-  for ( int layerIdx = 0; layerIdx < p->Source->GetLayerCount(); ++layerIdx )
+  int lastLayer = p->Source->GetLayerCount() - 1;
+  int startLayer =
+    this->ActiveLayer < 0 || this->ActiveLayer >= lastLayer ?
+    0 : this->ActiveLayer;
+  int endLayer = this->ActiveLayer < 0 || this->ActiveLayer >= lastLayer ?
+    lastLayer : this->ActiveLayer;
+  for ( int layerIdx = startLayer; layerIdx <= endLayer; ++layerIdx )
     {
     OGRLayer* layer = p->Source->GetLayer( layerIdx );
     if ( ! layer )

IO/GDAL/vtkGDALVectorReader.h

@@ -17,7 +17,10 @@
 // vtkGDALVectorReader is a source object that reads vector files and uses
 // GDAL as the underlying library for the task. GDAL is required for this
 // reader. The output of the reader is a vtkMultiBlockDataSet
-
+//
+// This filter uses the ActiveLayer member to only load entries from the
+// specified layer (when ActiveLayer >= 0).
+//
 // .SECTION See Also
 // vtkMultiBlockDataSet
 
@@ -60,7 +63,9 @@ public:
   int GetActiveLayerFeatureCount();
 
   // Description:
-  // Set and Get the active layer
+  // Set and Get the active layer.
+  // If ActiveLayer is less than 0 (the default is -1), then all
+  // layers are read. Otherwise, only the specified layer is read.
   vtkSetMacro(ActiveLayer,int);
   vtkGetMacro(ActiveLayer,int);