offset_scale_cartesian_coordinates.cuh

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/*
 * Copyright (c) 2023, NVIDIA CORPORATION.
 *
 * 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.
 */
 
#pragma once
 
#include <cuproj/detail/utility/cuda.hpp>
#include <cuproj/ellipsoid.hpp>
#include <cuproj/operation/operation.cuh>
#include <cuproj/projection_parameters.hpp>
 
#include <thrust/iterator/transform_iterator.h>
 
#include <algorithm>
 
namespace cuproj {
 
template <typename Coordinate, typename T = typename Coordinate::value_type>
class offset_scale_cartesian_coordinates : operation<Coordinate> {
 public:
  CUPROJ_HOST_DEVICE offset_scale_cartesian_coordinates(projection_parameters<T> const& params)
    : a_(params.ellipsoid_.a), ra_(T{1.0} / a_), x0_(params.x0), y0_(params.y0)
  {
  }
 
  CUPROJ_HOST_DEVICE Coordinate operator()(Coordinate const& coord, direction dir) const
  {
    if (dir == direction::FORWARD)
      return forward(coord);
    else
      return inverse(coord);
  }
 
 private:
  CUPROJ_HOST_DEVICE Coordinate forward(Coordinate const& coord) const
  {
    return coord * a_ + Coordinate{x0_, y0_};
  };
 
  CUPROJ_HOST_DEVICE Coordinate inverse(Coordinate const& coord) const
  {
    return (coord - Coordinate{x0_, y0_}) * ra_;
  };
 
  T a_;   // ellipsoid semi-major axis
  T ra_;  // inverse of ellipsoid semi-major axis
  T x0_;  // projection origin x
  T y0_;  // projection origin y
};
 
}  // namespace cuproj