otbScalarToRainbowRGBPixelFunctor.h

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/*
 * Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
 *
 * This file is part of Orfeo Toolbox
 *
 *     https://www.orfeo-toolbox.org/
 *
 * 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 otbScalarToRainbowRGBPixelFunctor_h
#define otbScalarToRainbowRGBPixelFunctor_h
 
#include "itkColormapFunction.h"
 
namespace otb
{
 
namespace Functor
{
 
template <class TRGBPixel>
class ITK_EXPORT HSVToRGBFunctor
{
public:
  HSVToRGBFunctor() = default;
  ~HSVToRGBFunctor() = default;
 
  TRGBPixel operator()(double h, double s, double v) const
  {
    const double onethird  = 1.0 / 3.0;
    const double onesixth  = 1.0 / 6.0;
    const double twothird  = 2.0 / 3.0;
    const double fivesixth = 5.0 / 6.0;
    double       r, g, b;
 
    // compute RGB from HSV
    if (h > onesixth && h <= onethird) // green/red
    {
      g = 1.0;
      r = (onethird - h) / onesixth;
      b = 0.0;
    }
    else if (h > onethird && h <= 0.5) // green/blue
    {
      g = 1.0;
      b = (h - onethird) / onesixth;
      r = 0.0;
    }
    else if (h > 0.5 && h <= twothird) // blue/green
    {
      b = 1.0;
      g = (twothird - h) / onesixth;
      r = 0.0;
    }
    else if (h > twothird && h <= fivesixth) // blue/red
    {
      b = 1.0;
      r = (h - twothird) / onesixth;
      g = 0.0;
    }
    else if (h > fivesixth && h <= 1.0) // red/blue
    {
      r = 1.0;
      b = (1.0 - h) / onesixth;
      g = 0.0;
    }
    else // red/green
    {
      r = 1.0;
      g = h / onesixth;
      b = 0.0;
    }
 
    // add Saturation to the equation.
    r = (s * r + (1.0 - s));
    g = (s * g + (1.0 - s));
    b = (s * b + (1.0 - s));
 
    r *= v;
    g *= v;
    b *= v;
 
    //         std::cout << h << ", " << s << ", " << v << " -> " << r << ", " << g << ", " << b << std::endl;
 
    using RGBComponentType = typename TRGBPixel::ComponentType;
    TRGBPixel ans;
    ans[0] = static_cast<RGBComponentType>(r);
    ans[1] = static_cast<RGBComponentType>(g);
    ans[2] = static_cast<RGBComponentType>(b);
    return ans;
  }
};
}
 
namespace Functor
{
 
template <class TScalar, class TRGBPixel = itk::RGBPixel<unsigned char>>
class ITK_EXPORT ScalarToRainbowRGBPixelFunctor : public itk::Function::ColormapFunction<TScalar, TRGBPixel>
//      public itk::Functor::ScalarToRGBPixelFunctor<TScalar>
{
public:
  ScalarToRainbowRGBPixelFunctor();
  ~ScalarToRainbowRGBPixelFunctor() = default;
 
  using Self                = ScalarToRainbowRGBPixelFunctor;
  using Superclass          = itk::Function::ColormapFunction<TScalar, TRGBPixel>;
  using Pointer             = itk::SmartPointer<Self>;
  using ConstPointer        = itk::SmartPointer<const Self>;
 
  itkNewMacro(Self);
 
  using RGBPixelType        = TRGBPixel;
  using RGBComponentType    = typename RGBPixelType::ComponentType;
  using ScalarType          = TScalar;
  using HSVToRGBFunctorType = HSVToRGBFunctor<RGBPixelType>;
 
  RGBPixelType operator()(const TScalar&) const override;
 
protected:
  RGBPixelType HSVToRGB(double h, double s, double v) const;
 
private:
  ScalarToRainbowRGBPixelFunctor(const Self&) = delete;
  void operator=(const Self&) = delete;
 
  HSVToRGBFunctorType m_HSVToRGBFunctor;
};
 
} // end namespace functor
 
} // end namespace itk
 
#ifndef OTB_MANUAL_INSTANTIATION
#include "otbScalarToRainbowRGBPixelFunctor.hxx"
#endif
 
#endif