RepeatExtrapolateImageFunction.h

/*
 * Medical Image Registration ToolKit (MIRTK)
 *
 * Copyright 2013-2015 Imperial College London
 * Copyright 2013-2015 Andreas Schuh
 *
 * 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
 *
 * 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 MIRTK_RepeatExtrapolateImageFunction_H
#define MIRTK_RepeatExtrapolateImageFunction_H

#include "mirtk/ExtrapolateImageFunction.h"

#include "mirtk/Math.h"
#include "mirtk/BaseImage.h"


namespace mirtk {


/**
 * Extrapolation of generic image by tiling/repeating it
 *
 * This extrapolation implements a periodic extension of the finite image.
 */
template <class TImage>
class GenericRepeatExtrapolateImageFunction
: public IndexExtrapolateImageFunction<TImage>
{
  mirtkExtrapolatorMacro(
    GenericRepeatExtrapolateImageFunction,
    Extrapolation_Repeat
  );

public:

  /// Constructor
  GenericRepeatExtrapolateImageFunction() {}

  /// Destructor
  virtual ~GenericRepeatExtrapolateImageFunction() {}

  /// Transform index such that it is inside the range [0, max]
  /// \note Use static function as RepeatExtrapolateImageFunction::Apply.
  static void Apply(int &index, int max)
  {
    if      (index < 0  ) index = max + (index + 1) % (max + 1);
    else if (index > max) index =        index      % (max + 1);
  }

  /// Transform continuous index such that it is inside the range [0, max + 1)
  /// \note Use static function as RepeatExtrapolateImageFunction::Apply.
  static void Apply(double &cindex, int max)
  {
    int    index    = ifloor(cindex);
    double fraction = cindex - index;
    Apply(index, max);
    cindex = index + fraction;
  }

  /// Transform index such that it is inside the range [0, max]
  virtual void TransformIndex(int &index, int max) const
  {
    Apply(index, max);
  }

};


/**
 * Extrapolation of any image by tiling/repeating it
 *
 * This extrapolation implements a periodic extension of the finite image.
 */
class RepeatExtrapolateImageFunction
: public GenericRepeatExtrapolateImageFunction<BaseImage>
{
  mirtkObjectMacro(RepeatExtrapolateImageFunction);

public:

  /// Constructor
  RepeatExtrapolateImageFunction() {}

  /// Destructor
  virtual ~RepeatExtrapolateImageFunction() {}

};


} // namespace mirtk

#endif // MIRTK_RepeatExtrapolateImageFunction_H