nearest.h

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/* Copyright (c) 2008-2022 the MRtrix3 contributors.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Covered Software is provided under this License on an "as is"
 * basis, without warranty of any kind, either expressed, implied, or
 * statutory, including, without limitation, warranties that the
 * Covered Software is free of defects, merchantable, fit for a
 * particular purpose or non-infringing.
 * See the Mozilla Public License v. 2.0 for more details.
 *
 * For more details, see http://www.mrtrix.org/.
 */
 
#ifndef __interp_nearest_h__
#define __interp_nearest_h__
 
#include "datatype.h"
#include "image_helpers.h"
#include "types.h"
#include "interp/base.h"
 
namespace MR
{
  namespace Interp
  {
 
    // @{
 
 
    template <class ImageType>
      class Nearest : public Base<ImageType> { MEMALIGN(Nearest<ImageType>)
      public:
        using typename Base<ImageType>::value_type;
 
        using Base<ImageType>::index;
        using Base<ImageType>::out_of_bounds;
        using Base<ImageType>::out_of_bounds_value;
 
        Nearest (const ImageType& parent, value_type value_when_out_of_bounds = Base<ImageType>::default_out_of_bounds_value()) :
          Base<ImageType> (parent, value_when_out_of_bounds) { }
 
 
        template <class VectorType>
          bool voxel (const VectorType& pos) {
            Base<ImageType>::intravoxel_offset (pos);
            if (out_of_bounds)
              return false;
            index(0) = std::round (pos[0]);
            index(1) = std::round (pos[1]);
            index(2) = std::round (pos[2]);
            return true;
          }
 
 
        template <class VectorType>
          FORCE_INLINE bool image (const VectorType& pos) {
            return voxel (Transform::voxelsize.inverse() * pos.template cast<default_type>());
          }
 
 
        template <class VectorType>
          FORCE_INLINE bool scanner (const VectorType& pos) {
            return voxel (Transform::scanner2voxel * pos.template cast<default_type>());
          }
 
 
        FORCE_INLINE value_type value () const {
          if (out_of_bounds)
            return out_of_bounds_value;
          return ImageType::value();
        }
 
 
        Eigen::Matrix<value_type, Eigen::Dynamic, 1> row (size_t axis) {
          assert (axis > 2);
          assert (axis < ImageType::ndim());
          if (out_of_bounds) {
            Eigen::Matrix<value_type, Eigen::Dynamic, 1> out_of_bounds_row (ImageType::size(axis));
            out_of_bounds_row.setOnes();
            out_of_bounds_row *= out_of_bounds_value;
            return out_of_bounds_row;
          }
          return ImageType::row(axis);
        }
 
    };
 
 
 
    template <class ImageType, typename... Args>
      inline Nearest<ImageType> make_nearest (const ImageType& parent, Args&&... args) {
        return Nearest<ImageType> (parent, std::forward<Args> (args)...);
      }
 
 
 
 
  }
}
 
#endif