BUG: Use proper GenerateOutputInformation method to set vector length

The GernerateOutputInformation method is the correct method to
overrride when specify image information and meta-data.

Remove extraneous setting of the image's number of components. The
filter will now throw an exception if the improper fixed number of
components is set for the output image type.

Author: blowekamp

include/itkCoocurrenceTextureFeaturesImageFilter.h

@@ -227,7 +227,7 @@ class ITK_TEMPLATE_EXPORT CoocurrenceTextureFeaturesImageFilter:public ImageToIm
   virtual void AfterThreadedGenerateData() ITK_OVERRIDE;
   virtual void ThreadedGenerateData(const OutputRegionType & outputRegionForThread,
                                     ThreadIdType threadId) ITK_OVERRIDE;
-  virtual void UpdateOutputInformation() ITK_OVERRIDE;
+  virtual void GenerateOutputInformation() ITK_OVERRIDE;
 
 private:
   typename DigitalisedImageType::Pointer  m_DigitalisedInputImageg;

include/itkCoocurrenceTextureFeaturesImageFilter.hxx

@@ -103,15 +103,6 @@ CoocurrenceTextureFeaturesImageFilter<TInputImage, TOutputImage>
 
   functorF->Update();
   m_DigitalisedInputImageg = functorF->GetOutput();
-
-  // Support VectorImages by setting number of components on output.
-  OutputImageType * outputPtr = this->GetOutput();
-  if ( strcmp(outputPtr->GetNameOfClass(), "VectorImage") == 0 )
-      {
-      typedef typename TOutputImage::AccessorFunctorType AccessorFunctorType;
-      AccessorFunctorType::SetVectorLength( outputPtr, 8 );
-      }
-  outputPtr->Allocate();
 }
 
 template<typename TInputImage, typename TOutputImage>
@@ -249,16 +240,20 @@ CoocurrenceTextureFeaturesImageFilter<TInputImage, TOutputImage>
 template<typename TInputImage, typename TOutputImage>
 void
 CoocurrenceTextureFeaturesImageFilter<TInputImage, TOutputImage>
-::UpdateOutputInformation()
+::GenerateOutputInformation()
 {
   // Call superclass's version
-  Superclass::UpdateOutputInformation();
-
-  if ( strcmp(this->GetOutput()->GetNameOfClass(), "VectorImage") == 0 )
-      {
-      typedef typename TOutputImage::AccessorFunctorType AccessorFunctorType;
-      AccessorFunctorType::SetVectorLength( this->GetOutput(), 8 );
-      }
+  Superclass::GenerateOutputInformation();
+
+  OutputImageType* output = this->GetOutput();
+  // If the output image type is a VectorImage the number of
+  // components will be properly sized if before allocation, if the
+  // output is a fixed width vector and the wrong number of
+  // components, then an exception will be thrown.
+  if ( output->GetNumberOfComponentsPerPixel() != 8 )
+    {
+    output->SetNumberOfComponentsPerPixel( 8 );
+    }
 }
 
 template<typename TInputImage, typename TOutputImage>