/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef itkFlipImageFilter_h
#define itkFlipImageFilter_h

#include "itkImageToImageFilter.h"
#include "itkFixedArray.h"

namespace itk
{
/** \class FlipImageFilter
 * \brief Flips an image across user specified axes.
 *
 * FlipImageFilter flips an image across user specified axes.
 * The flip axes are set via method SetFlipAxes( array ) where
 * the input is a FixedArray<bool,ImageDimension>. The image
 * is flipped across axes for which array[i] is true.
 *
 * In terms of grid coordinates the image is flipped within
 * the LargestPossibleRegion of the input image. As such,
 * the LargestPossibleRegion of the ouput image is the same
 * as the input.
 *
 * In terms of geometric coordinates, the output origin
 * is such that the image is flipped with respect to the
 * coordinate axes.
 *
 * \ingroup GeometricTransform
 * \ingroup MultiThreaded
 * \ingroup Streamed
 * \ingroup ITKImageGrid
 *
 * \wiki
 * \wikiexample{Images/FlipImageFilter,Flip an image over specified axes}
 * \endwiki
 */
template< typename TImage >
class FlipImageFilter:
  public ImageToImageFilter< TImage, TImage >
{
public:
  /** Standard class typedefs. */
  typedef FlipImageFilter                      Self;
  typedef ImageToImageFilter< TImage, TImage > Superclass;
  typedef SmartPointer< Self >                 Pointer;
  typedef SmartPointer< const Self >           ConstPointer;

  /** Method for creation through the object factory. */
  itkNewMacro(Self);

  /** Run-time type information (and related methods). */
  itkTypeMacro(FlipImageFilter, ImageToImageFilter);

  /** ImageDimension enumeration */
  itkStaticConstMacro(ImageDimension, unsigned int, TImage::ImageDimension);

  /** Inherited types */
  typedef typename Superclass::InputImagePointer      InputImagePointer;
  typedef typename Superclass::InputImageConstPointer InputImageConstPointer;
  typedef typename Superclass::OutputImagePointer     OutputImagePointer;
  typedef typename Superclass::OutputImageRegionType  OutputImageRegionType;

  /** Index related types */
  typedef typename TImage::IndexType         IndexType;
  typedef typename IndexType::IndexValueType IndexValueType;

  /** FlipAxesArray type */
  typedef FixedArray< bool, itkGetStaticConstMacro(ImageDimension) > FlipAxesArrayType;

  /** Set/Get the axis to be flipped. The image is flipped along axes
   * for which array[i] is true. */
  itkSetMacro(FlipAxes, FlipAxesArrayType);
  itkGetConstMacro(FlipAxes, FlipAxesArrayType);

/** Controls how the output origin is computed. If FlipAboutOrigin is
 * "on", the flip will occur about the origin of the axis, otherwise,
 * the flip will occur about the center of the axis.
 */
  itkBooleanMacro(FlipAboutOrigin);
  itkGetConstMacro(FlipAboutOrigin, bool);
  itkSetMacro(FlipAboutOrigin, bool);

  /** FlipImageFilter produces an image with different origin and
   * direction than the input image. As such, FlipImageFilter needs to
   * provide an implementation for GenerateOutputInformation() in
   * order to inform the pipeline execution model.  The original
   * documentation of this method is below.
   * \sa ProcessObject::GenerateOutputInformaton() */
  virtual void GenerateOutputInformation() ITK_OVERRIDE;

  /** FlipImageFilter needs different input requested region than the output
   * requested region.  As such, FlipImageFilter needs to provide an
   * implementation for GenerateInputRequestedRegion() in order to inform the
   * pipeline execution model.
   * \sa ProcessObject::GenerateInputRequestedRegion() */
  virtual void GenerateInputRequestedRegion() ITK_OVERRIDE;

protected:
  FlipImageFilter();
  ~FlipImageFilter() {}
  void PrintSelf(std::ostream & os, Indent indent) const ITK_OVERRIDE;

  /** FlipImageFilter can be implemented as a multithreaded filter.
   * Therefore, this implementation provides a ThreadedGenerateData() routine
   * which is called for each processing thread. The output image data is
   * allocated automatically by the superclass prior to calling
   * ThreadedGenerateData().  ThreadedGenerateData can only write to the
   * portion of the output image specified by the parameter
   * "outputRegionForThread"
   *
   * \sa ImageToImageFilter::ThreadedGenerateData(),
   *     ImageToImageFilter::GenerateData()  */
  void ThreadedGenerateData(const OutputImageRegionType & outputRegionForThread,
                            ThreadIdType threadId) ITK_OVERRIDE;

private:
  FlipImageFilter(const Self &) ITK_DELETE_FUNCTION;
  void operator=(const Self &) ITK_DELETE_FUNCTION;

  FlipAxesArrayType m_FlipAxes;
  bool              m_FlipAboutOrigin;
};
} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkFlipImageFilter.hxx"
#endif

#endif
