subset.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 __adapter_subset_h__
#define __adapter_subset_h__
 
#include "image.h"
#include "adapter/base.h"
 
namespace MR
{
  namespace Adapter {
 
    template <class ImageType>
      class Subset :
        public Base<Subset<ImageType>,ImageType>
    { MEMALIGN(Subset<ImageType>)
      public:
 
        using base_type = Base<Subset<ImageType>, ImageType>;
        using value_type = typename ImageType::value_type;
 
        using base_type::name;
        using base_type::spacing;
 
        template <class VectorType>
          Subset (const ImageType& original, const VectorType& from, const VectorType& size) :
            base_type (original),
            from_ (container_cast<decltype(from_)>(from)),
            size_ (container_cast<decltype(size_)>(size)),
            transform_ (original.transform()) {
 
              for (size_t n = 0; n < ndim(); ++n) {
                if (size_[n] < 1)
                  throw Exception ("FIXME: sizes requested for Subset adapter must be positive");
                if (from_[n] + size_[n] > original.size(n) || from_[n] < 0)
                  throw Exception ("FIXME: dimensions requested for Subset adapter are out of bounds!");
              }
 
              for (size_t j = 0; j < 3; ++j)
                for (size_t i = 0; i < 3; ++i)
                  transform_(i,3) += from[j] * spacing(j) * transform_(i,j);
            }
 
        void reset () {
          for (size_t n = 0; n < ndim(); ++n)
            set_pos (n, 0);
        }
 
        size_t ndim () const { return size_.size(); }
        ssize_t size (size_t axis) const { return size_ [axis]; }
        const transform_type& transform() const { return transform_; }
 
        ssize_t get_index (size_t axis) const { return parent().index(axis)-from_[axis]; }
        void move_index (size_t axis, ssize_t increment) { parent().index(axis) += increment; }
 
      protected:
        using base_type::parent;
        const vector<ssize_t> from_, size_;
        transform_type transform_;
    };
 
  }
}
 
#endif