ColorModelConversions.h

/**
 * @file ColorModelConversions.h
 * 
 * Declaration and implementation of class ColorModelConversions
 */ 

#ifndef __ColorModelConversions_h_
#define __ColorModelConversions_h_
#include <iostream>
#include "math.h"
//TODO: solve the include jobs
/**
* A class that defines static conversions between color models for single pixels.
*/
class ColorModelConversions
{
public:
  /** Converts an YCbCr pixel into an RGB pixel.
   *  @param Y The Y channel of the source pixel.
   *  @param Cb The Cb channel of the source pixel.
   *  @param Cr The Cr channel of the source pixel.
   *  @param R The R channel of the target pixel.
   *  @param G The G channel of the target pixel.
   *  @param B The B channel of the target pixel.
   */
  static void fromYCbCrToRGB(unsigned char Y,
                             unsigned char Cb,
                             unsigned char Cr,
                             unsigned char& R,
                             unsigned char& G,
                             unsigned char& B)
  {
/*	  int r = (int)(Y + 1.4021 * (Cr - 128)),
	      g = (int)(Y - 0.3456 * (Cb - 128) - 0.71448 * (Cr - 128)),
	      b = (int)(Y + 1.7710 * (Cb - 128));*/

    int b = Y + ((1436 * (Cr - 128)) >> 10),
        g = Y - ((354 * (Cb - 128) + 732 * (Cr - 128)) >> 10),
        r = Y + ((1814 * (Cb - 128)) >> 10);

      /*
      int C = Y - 16;
      int D = Cb - 128;
      int E = Cr - 128;
      int g = 1.164f * C + 1.596f * E;
      int r = 1.164f * C - 0.813f * E - 0.391f * D;
      int b = 1.164f * C +2.018 * E;
      */
      if(r < 0) r = 0; else if(r > 255) r = 255;
      if(g < 0) g = 0; else if(g > 255) g = 255;
      if(b < 0) b = 0; else if(b > 255) b = 255;


    R = (unsigned char) r;
    G = (unsigned char) g;
    B = (unsigned char) b;
  }

  static void fromYCbCrToRGB(unsigned char* sourceImg,unsigned char* destImg, int width,int height)
  {
      int yuvLen = width * height * 2;// div by four because of the uY1vY2
      int rgbIndex=0, yuvIndex=0;
      //unsigned char* destImg = new unsigned char[rgbLen];
      while(yuvIndex < yuvLen)
      {
          unsigned char Y1 = sourceImg[yuvIndex++];
          unsigned char U = sourceImg[yuvIndex++];
          unsigned char Y2 = sourceImg[yuvIndex++];
          unsigned char V = sourceImg[yuvIndex++];
          fromYCbCrToRGB(Y1,U,V,
                           destImg[rgbIndex++],//R
                           destImg[rgbIndex++],//G
                           destImg[rgbIndex++]);//B

          fromYCbCrToRGB(Y2,U,V,
                           destImg[rgbIndex++],//R
                           destImg[rgbIndex++],//G
                           destImg[rgbIndex++]);//B
      }

  }

  /** Converts an RGB pixel into an YCbCr pixel.
   *  @param R The R channel of the source pixel.
   *  @param G The G channel of the source pixel.
   *  @param B The B channel of the source pixel.
   *  @param Y The Y channel of the target pixel.
   *  @param Cb The Cb channel of the target pixel.
   *  @param Cr The Cr channel of the target pixel.
   */
  static void fromRGBToYCbCr(unsigned char R,
                             unsigned char G,
                             unsigned char B,
                             unsigned char& Y,
                             unsigned char& Cb,
                             unsigned char& Cr)
  {
    int y = (int)( 0.2990 * R + 0.5870 * G + 0.1140 * B),
        cr = 127 + (int)(-0.1687 * R - 0.3313 * G + 0.5000 * B),
        cb = 127 + (int)( 0.5000 * R - 0.4187 * G - 0.0813 * B);
    if(y < 0) y = 0; else if(y > 255) y = 255;
    if(cb < 0) cb = 0; else if(cb > 255) cb = 255;
    if(cr < 0) cr = 0; else if(cr > 255) cr = 255;
    Y = (unsigned char) y;
    Cb = (unsigned char) cb;
    Cr = (unsigned char) cr;
  }
  static double max(double a, double b, double c)
  {
      if( a > b && a > c)
          return a;
      if( b > c && b > a)
          return b;
      if( c > a && c > b)
          return c;
  }
  static double min(double a, double b, double c)
  {
      if( a < b && a < c)
          return a;
      if( b < c && b < a)
          return b;
      if( c < a && c < b)
          return c;
  }

  static void fromRGBtoHSL(unsigned char R,unsigned char G,unsigned char B, int &H,unsigned char &S,unsigned char &L)
  {

          float r = (float)R / 255, g = (float)G / 255, b = (float)B / 255;
          float Max = max(r, g, b);
          float Min = min(r, g, b);
          float h, s, l = (float)(r+g+b) / 3;
          if(Max == Min)
              h = s = 0; // achromatic
          else
          {
              float d = (float)Max - Min;
              s = l >= 0.5 ? d / (2 - Max - Min) : d / (Max + Min);
              if (Max == r)
              {h = (g - b) / d + (g < b ? 6 : 0);}
              else if(Max == g)
              { h = (b - r) / d + 2;}
                  else if(Max == b)
              {h = (r - g) / d + 4;}
              h *= 60;
          }

      H = (int)h;
      S = s*100;
      L = l*100;

  }

  static void fromYUVtoHSL(unsigned char Y,unsigned char U,unsigned char V,int &H,unsigned char &S,unsigned char &L)
  {
    unsigned char R,G,B;
    fromYCbCrToRGB(Y,U,V,R,G,B);
    fromRGBtoHSL(R,G,B,H,S,L);
  }
    /** Converts an YCbCr pixel into an HSI pixel.
   *  @param Y The Y channel of the source pixel.
   *  @param Cb The Cb channel of the source pixel.
   *  @param Cr The Cr channel of the source pixel.
   *  @param H The H channel of the target pixel.
   *  @param S The S channel of the target pixel.
   *  @param I The I channel of the target pixel.
   */
  static void fromYCbCrToHSI(unsigned char Y,
                             unsigned char Cb,
                             unsigned char Cr,
                             unsigned char& H,
                             unsigned char& S,
                             unsigned char& I)
  {
    const double sqrt3 = 1.732050808;
    unsigned char R,
                  G,
                  B;
    fromYCbCrToRGB(Y, Cb, Cr, R, G, B);
    I = R;
    if(G > I) I = G;
    if(B > I) I = B;
    if(I)
    {
      S = R;
      if(G < S) S = G;
      if(B < S) S = B;
      S = (unsigned char) (255 - 255 * S / I);
      if(S)
      {
        int h = int(atan2(sqrt3 * (G - B), 2 * R - G - B) / M_PI_2 * 256);
        if(h > 255) h -= 256;
        else if(h < 0) h += 256;
        H = (unsigned char) h;
      }
      else
        H = 0;
    }
    else
      S = H = 0;
  }

  /** Converts an HSI pixel into an YCbCr pixel.
   *  @param H The H channel of the source pixel.
   *  @param S The S channel of the source pixel.
   *  @param I The I channel of the source pixel.
   *  @param Y The Y channel of the target pixel.
   *  @param Cb The Cb channel of the target pixel.
   *  @param Cr The Cr channel of the target pixel.
   */
  static void fromHSIToYCbCr(unsigned char H,
                             unsigned char S,
                             unsigned char I,
                             unsigned char& Y,
                             unsigned char& Cb,
                             unsigned char& Cr)
  {
    double h = 1.0 - H / 255.0,
           s = S / 255.0,
           r,
           g,
           b;

    if(h < 1.0 / 3.0)
    {
      g = (1 - s) / 3;
      b = (1 + s * cos(M_PI_2 * h) / cos(M_PI_2 * (1.0 / 6.0 - h))) / 3.0;
      r = 1 - (g + b);
    } 
    else if(h < 2.0 / 3.0)
    {
      h -= 1.0 / 3.0;
      b = (1 - s) / 3;
      r = (1 + s * cos(M_PI_2 * h) / cos(M_PI_2 * (1.0 / 6.0 - h))) / 3.0;
      g = 1 - (b + r);
    } 
    else 
    {
      h -= 2.0 / 3.0;
      r = (1 - s) / 3;
      g = (1 + s * cos(M_PI_2 * h) / cos(M_PI_2 * (1.0 / 6.0 - h))) / 3.0;
      b = 1 - (r + g);
    }

    r *= I * 3;
    g *= I * 3;
    b *= I * 3;
    if(r > 255)
      r = 255;
    if(g > 255)
      g = 255;
    if(b > 255)
      b = 255;

    fromRGBToYCbCr((unsigned char) r,
                   (unsigned char) g,
                   (unsigned char) b,
                   Y, Cb, Cr);
  }

  /** Converts an YCbCr pixel into a TSL pixel.
   *  @param Y The Y channel of the source pixel.
   *  @param Cb The Cb channel of the source pixel.
   *  @param Cr The Cr channel of the source pixel.
   *  @param T The T channel of the target pixel.
   *  @param S The S channel of the target pixel.
   *  @param L The L channel of the target pixel.
   */
  static void fromYCbCrToTSL(unsigned char Y,
                             unsigned char Cb,
                             unsigned char Cr,
                             unsigned char& T,
                             unsigned char& S,
                             unsigned char& L)
  {
    const double pi2_div = 0.15915494309189533576888376337251;  /* 1.0 / (PI * 2.0) */

    double cb = Cb - 128.0,
           cr = Cr - 128.0,
           tmp = 1.0 / (4.3403 * Y +  2.0 * cr + cb),
           tmp_r = (-0.6697 * cr + 1.6959 * cb) * tmp,
           tmp_g = (-1.168  * cr - 1.3626 * cb) * tmp,
           tmp_b = ( 1.8613 * cr - 0.331  * cb) * tmp;
    double t_out;
    if(tmp_g > 0.0)
      t_out = (atan2(tmp_r, tmp_g) * pi2_div + 0.25) * 255.0;
    else if(tmp_g < 0.0)
      t_out = (atan2(-tmp_r, -tmp_g) * pi2_div + 0.75) * 255.0;
    else
      t_out = 0.0;
    double s_out = sqrt(1.8 * (tmp_r * tmp_r + tmp_g * tmp_g + tmp_b * tmp_b)) * 255.0;

    if(t_out < 0.0)
      t_out = 0.0;
    else if(t_out > 255.0)
      t_out = 255.0;
    if(s_out < 0.0)
      s_out = 0.0;
    else if(s_out > 255.0)
      s_out = 255.0;

    T = (unsigned char) t_out;
    S = (unsigned char) s_out;
    L = Y;
  }

  /** Converts a TSL pixel into an YCbCr pixel.
   *  @param T The T channel of the source pixel.
   *  @param S The S channel of the source pixel.
   *  @param L The L channel of the source pixel.
   *  @param Y The Y channel of the target pixel.
   *  @param Cb The Cr channel of the target pixel.
   *  @param Cr The Cr channel of the target pixel.
   */
  static void fromTSLToYCbCr(unsigned char T, 
                             unsigned char S, 
                             unsigned char L,
                             unsigned char& Y,
                             unsigned char& Cb,
                             unsigned char& Cr) 
  {
    double rad = S * 0.555 / 255.0,
           phi = (T * 2 / 255.0 + 0.25) * M_PI,
           cb = 128 + rad * cos(phi) * 255.0,
           cr = 128 - rad * sin(phi) * 255.0;
    Y = L;

    if(cb < 0)
      cb = 0;
    else if(cb > 255)
      cb = 255;
    if(cr < 0)
      cr = 0;
    else if(cr > 255)
      cr = 255;
    Cb = (unsigned char) cb;
    Cr = (unsigned char) cr;
  }

  /** Converts a TSL pixel into an YCbCr pixel.
   *  @param t The T channel of the source pixel.
   *  @param s The S channel of the source pixel.
   *  @param l The L channel of the source pixel.
   *  @param r The R channel of the target pixel.
   *  @param g The G channel of the target pixel.
   *  @param b The B channel of the target pixel.
   */
  static void fromTSLToRGB(unsigned char t, 
                           unsigned char s, 
                           unsigned char l,
                           unsigned char& r,
                           unsigned char& g,
                           unsigned char& b) 
  {
    double y1, u1, v1, r1, g1, b1, rad, phi;
    
    /* Convert TSL to YUV */
    rad = (((double) s) * 0.555) / 255.0;
    phi = (((double) t) * 2.0 * 3.14159) / 255.0;
    phi += 0.25 * 3.14159;
    y1 = (double) l;
    u1 =  (rad * cos(phi)) * 255.0;
    v1 = -(rad * sin(phi)) * 255.0;

    /* Crop UV */
    if (u1 < -128.0)
    {
      u1 = -128.0;
    }
    else if (u1 > 127.0)
    {
      u1 = 127.0;
    }
    if (v1 < -128.0)
    {
      v1 = -128.0;
    }
    else if (v1 > 127.0)
    {
      v1 = 127.0;
    }

    /* Convert YUV to RGB */
    r1 = y1 + 1.371 * v1;
    g1 = y1 - 0.336 * u1 - 0.698 * v1;
    b1 = y1 + 1.732 * u1;

    /* Crop RGB */
    if (r1 < 0.0)
    {
      r1 = 0.0;
    }
    else if (r1 > 255.0)
    {
      r1 = 255.0;
    }
    if (g1 < 0.0)
    {
      g1 = 0.0;
    }
    else if (g1 > 255.0)
    {
      g1 = 255.0;
    }
    if (b1 < 0.0)
    {
      b1 = 0.0;
    }
    else if (b1 > 255.0)
    {
      b1 = 255.0;
    }

    /* Return values */
    r = (unsigned char) r1;
    g = (unsigned char) g1;
    b = (unsigned char) b1;
  }
};

#endif //__ColorModelConversions_h_