vpRGBa.h

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2025 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See https://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * RGBA pixel.
 */

 
#ifndef VP_RGBA_H
#define VP_RGBA_H
 
#include <assert.h>
 
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpColVector.h>
 
#if ((__cplusplus >= 201703L) || (defined(_MSVC_LANG) && (_MSVC_LANG >= 201703L)))
#include <type_traits>
#endif
 
 
BEGIN_VISP_NAMESPACE
#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
template <typename T, bool>
class vpHSV;
#endif
class VISP_EXPORT vpRGBa
{
public:
  enum AlphaDefault { alpha_default = 255 };

  inline vpRGBa() : R(0), G(0), B(0), A(vpRGBa::alpha_default) { }

  inline vpRGBa(unsigned char r, unsigned char g, unsigned char b, unsigned char a = vpRGBa::alpha_default)
    : R(r), G(g), B(b), A(a)
  { }

  VP_EXPLICIT inline vpRGBa(unsigned char v) : R(v), G(v), B(v), A(v) { }

  VP_EXPLICIT inline vpRGBa(unsigned int v)
  {
    assert(v < 256);
    unsigned char v_uc = static_cast<unsigned char>(v);
    R = v_uc;
    G = v_uc;
    B = v_uc;
    A = v_uc;
  }

  VP_EXPLICIT inline vpRGBa(int v)
  {
    assert(v >=0 && v < 256);
    unsigned char v_uc = static_cast<unsigned char>(v);
    R = v_uc;
    G = v_uc;
    B = v_uc;
    A = v_uc;
  }
 
#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
#ifndef VISP_PYTHON_PREPROCESSOR_RUNNING
  template <typename T, bool useFullScale, typename std::enable_if<std::is_same<T, unsigned char>::value, int>::type = 0>
  VP_EXPLICIT vpRGBa(const vpHSV<T, useFullScale> &hsv)
  {
    buildFrom<T, useFullScale, float>(hsv);
  }
 
  template <typename T, bool useFullScale, typename std::enable_if<std::is_floating_point<T>::value, int>::type = 0>
  VP_EXPLICIT vpRGBa(const vpHSV<T, useFullScale> &hsv)
  {
    buildFrom<T, useFullScale>(hsv);
  }
#endif

  template<typename T, bool useFullScale, typename U = float >
  typename std::enable_if<std::is_same<U, float>::value &&std::is_same<T, unsigned char>::value, vpRGBa &>::type
    buildFrom(const vpHSV<T, useFullScale> &other)
  {
    vpHSV<U, useFullScale> hsv(other);
    buildFrom(hsv);
    return *this;
  }

  template<typename T, bool useFullScale>
  typename std::enable_if<std::is_floating_point<T>::value, vpRGBa &>::type
    buildFrom(const vpHSV<T, useFullScale> &hsv)
  {
    T hue = hsv.H, saturation = hsv.S, value = hsv.V;
    T h = hue * static_cast<T>(6.0);
    T s = saturation;
    T v = value;
 
    if (vpMath::equal(h, static_cast<T>(6.0), std::numeric_limits<T>::epsilon())) {
      h = 0.0;
    }
 
    T f = h - static_cast<int>(h);
    T p = v * static_cast<T>(1.0 - s);
    T q = v * static_cast<T>(1.0 - (s * f));
    T t = v * static_cast<T>(1.0 - (s * (1.0 - f)));
 
    const int val_2 = 2;
    const int val_3 = 3;
    const int val_4 = 4;
    switch (static_cast<int>(h)) {
    case 0:
      hue = v;
      saturation = t;
      value = p;
      break;
 
    case 1:
      hue = q;
      saturation = v;
      value = p;
      break;
 
    case val_2:
      hue = p;
      saturation = v;
      value = t;
      break;
 
    case val_3:
      hue = p;
      saturation = q;
      value = v;
      break;
 
    case val_4:
      hue = t;
      saturation = p;
      value = v;
      break;
 
    default: // case 5:
      hue = v;
      saturation = p;
      value = q;
      break;
    }
 
    R = static_cast<unsigned char>(vpMath::round(hue * 255.0));
    G = static_cast<unsigned char>(vpMath::round(saturation * 255.0));
    B = static_cast<unsigned char>(vpMath::round(value * 255.0));
    A = alpha_default;
    return *this;
  }
#endif

#if ((__cplusplus >= 201103L) || (defined(_MSVC_LANG) && (_MSVC_LANG >= 201103L))) // Check if cxx11 or higher
  inline vpRGBa(const vpRGBa &v) = default;
#else
  inline vpRGBa(const vpRGBa &v) : R(v.R), G(v.G), B(v.B), A(v.A) { }
#endif

  VP_EXPLICIT inline vpRGBa(const vpColVector &v) : R(0), G(0), B(0), A(vpRGBa::alpha_default) { *this = v; }
 
  // We cannot add here the following destructor without changing the
  // hypothesis that the size of this class is 4. With the destructor it
  // becomes 16 that does break a lot of things around image conversions
  // virtual ~vpRGBa() {}; // Not to implement
 
  vpRGBa &operator=(const unsigned char &v);
  vpRGBa &operator=(const unsigned int &v);
  vpRGBa &operator=(const int &v);
#if ((__cplusplus >= 201103L) || (defined(_MSVC_LANG) && (_MSVC_LANG >= 201103L))) // Check if cxx11 or higher
  vpRGBa &operator=(vpRGBa &&v) = default;
  vpRGBa &operator=(const vpRGBa &v) = default;
#else
  vpRGBa &operator=(const vpRGBa &v)
  {
    this->R = v.R;
    this->G = v.G;
    this->B = v.B;
    this->A = v.A;
    return *this;
  }
#endif
  vpRGBa &operator=(const vpColVector &v);
  bool operator==(const vpRGBa &v) const;
  bool operator!=(const vpRGBa &v) const;
 
  vpColVector operator-(const vpRGBa &v) const;
  vpRGBa operator+(const vpRGBa &v) const;
  vpColVector operator-(const vpColVector &v) const;
  vpColVector operator+(const vpColVector &v) const;
  vpColVector operator*(const float &v) const;
  vpColVector operator*(const double &v) const;
 
  bool operator<(const vpRGBa &v) const;
  bool operator>(const vpRGBa &v) const;
 
  friend VISP_EXPORT std::ostream &operator<<(std::ostream &os, const vpRGBa &rgba);
 
#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
  static constexpr unsigned char nbChannels = 4;
#endif
public:
  unsigned char R; 
  unsigned char G; 
  unsigned char B; 
  unsigned char A; 
 
  friend VISP_EXPORT vpRGBa operator*(const double &x, const vpRGBa &rgb);
};
 
#if ((__cplusplus >= 201703L) || (defined(_MSVC_LANG) && (_MSVC_LANG >= 201703L)))
static_assert(std::is_trivially_assignable_v<vpRGBa, vpRGBa>);
static_assert(std::is_trivially_copyable_v<vpRGBa>);
#endif
 
END_VISP_NAMESPACE
#endif