spacebox/src/Color.cpp

#include "Color.hpp"

Color::Color() : Color(0, 0, 0, 255) {}

Color::Color(std::uint8_t r, std::uint8_t g, std::uint8_t b, std::uint8_t a) : r(r), g(g), b(b), a(a) {};

Color::Color(const SDL_Color& color) : Color(color.r, color.g, color.b, color.a) {};

void Color::set_rgb_float(const float& rf, const float& gf, const float& bf)
{
    r = std::round(255.0f * rf);
    g = std::round(255.0f * gf);
    b = std::round(255.0f * bf);
}

void Color::set_hsv(const float& h, const float& s, const float& v)
{
    float rf, gf, bf;
    HSVtoRGB(rf, gf, bf, h, s, v);
    set_rgb_float(rf, gf, bf);
}

void Color::shift_hue(float offset)
{
    float h, s, v;
    float rf = r / 255.0f, gf = g / 255.0f, bf = b / 255.0f;
    RGBtoHSV(rf, gf, bf, h, s, v);
    h = std::fmod(h + offset, 360.0);
    HSVtoRGB(rf, gf, bf, h, s, v);
    set_rgb_float(rf, gf, bf);
}

SDL_Color Color::get_sdl_color()
{
    return {r, g, b, a};
}

std::ostream& operator<<(std::ostream& out, const Color& color)
{
    float h, s, v;
    RGBtoHSV(color.r / 255.0f, color.g / 255.0f, color.b / 255.0f, h, s, v);
    out << "{r=" << static_cast<int>(color.r) << ", g=" << static_cast<int>(color.g) << ", b=" <<
        static_cast<int>(color.b) << ", a= " << static_cast<int>(color.a) << ", h=" << h <<
        ", s=" << s << ", v=" << v << "}";
    return out;
}

/*
  The following copyright applies to RGBtoHSV and HSVtoRGB:
*/

//
// Copyright (c) 2014, Jan Winkler <winkler@cs.uni-bremen.de>
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of Universität Bremen nor the names of its
//       contributors may be used to endorse or promote products derived from
//       this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

/*! \brief Convert RGB to HSV color space
  
  Converts a given set of RGB values `r', `g', `b' into HSV
  coordinates. The input RGB values are in the range [0, 1], and the
  output HSV values are in the ranges h = [0, 360], and s, v = [0,
  1], respectively.
  
  \param fR Red component, used as input, range: [0, 1]
  \param fG Green component, used as input, range: [0, 1]
  \param fB Blue component, used as input, range: [0, 1]
  \param fH Hue component, used as output, range: [0, 360]
  \param fS Hue component, used as output, range: [0, 1]
  \param fV Hue component, used as output, range: [0, 1]
  
*/
void RGBtoHSV(const float& fR, const float& fG, const float& fB, float& fH, float& fS, float& fV) {
    float fCMax = std::max(std::max(fR, fG), fB);
    float fCMin = std::min(std::min(fR, fG), fB);
  float fDelta = fCMax - fCMin;
  
  if(fDelta > 0) {
    if(fCMax == fR) {
        fH = 60 * (std::fmod(((fG - fB) / fDelta), 6));
    } else if(fCMax == fG) {
      fH = 60 * (((fB - fR) / fDelta) + 2);
    } else if(fCMax == fB) {
      fH = 60 * (((fR - fG) / fDelta) + 4);
    }
    
    if(fCMax > 0) {
      fS = fDelta / fCMax;
    } else {
      fS = 0;
    }
    
    fV = fCMax;
  } else {
    fH = 0;
    fS = 0;
    fV = fCMax;
  }
  
  if(fH < 0) {
    fH = 360 + fH;
  }
}

/*! \brief Convert HSV to RGB color space
  
  Converts a given set of HSV values `h', `s', `v' into RGB
  coordinates. The output RGB values are in the range [0, 1], and
  the input HSV values are in the ranges h = [0, 360], and s, v =
  [0, 1], respectively.
  
  \param fR Red component, used as output, range: [0, 1]
  \param fG Green component, used as output, range: [0, 1]
  \param fB Blue component, used as output, range: [0, 1]
  \param fH Hue component, used as input, range: [0, 360]
  \param fS Hue component, used as input, range: [0, 1]
  \param fV Hue component, used as input, range: [0, 1]
  
*/
void HSVtoRGB(float& fR, float& fG, float& fB, const float& fH, const float& fS, const float& fV) {
  float fC = fV * fS; // Chroma
  float fHPrime = std::fmod(fH / 60.0, 6);
  float fX = fC * (1 - std::fabs(std::fmod(fHPrime, 2) - 1));
  float fM = fV - fC;
  
  if(0 <= fHPrime && fHPrime < 1) {
    fR = fC;
    fG = fX;
    fB = 0;
  } else if(1 <= fHPrime && fHPrime < 2) {
    fR = fX;
    fG = fC;
    fB = 0;
  } else if(2 <= fHPrime && fHPrime < 3) {
    fR = 0;
    fG = fC;
    fB = fX;
  } else if(3 <= fHPrime && fHPrime < 4) {
    fR = 0;
    fG = fX;
    fB = fC;
  } else if(4 <= fHPrime && fHPrime < 5) {
    fR = fX;
    fG = 0;
    fB = fC;
  } else if(5 <= fHPrime && fHPrime < 6) {
    fR = fC;
    fG = 0;
    fB = fX;
  } else {
    fR = 0;
    fG = 0;
    fB = 0;
  }
  
  fR += fM;
  fG += fM;
  fB += fM;
}