RGB to HSV

Calc_RGB2HSV.c

//Calc_RGB2HSV.c
// by Dzone 140725_14:14 

#include <stdio.h>

void Cacl_RGB2HSV( unsigned int, unsigned int , unsigned int ,  double *, double *, double *);


void Cacl_RGB2HSV(
 unsigned int uiRed, unsigned int uiGreen, unsigned int uiBlue, 
 double *pdH, double *pdS, double *pdV)
{
	double dMax,dMin,dDiv;
	double dBuf=0;
	double dRed = (double)uiRed/(double)255;
	double dGreen = (double)uiGreen/(double)255;
	double dBlue = (double)uiBlue/(double)255;
	double dGetR,dGetG,dGetB;
	unsigned int uiFlagGray=0;
	unsigned int uiMaxIndex=1;// R=1,G=2,B=3
	unsigned int uiMinIndex=1;// R=1,G=2,B=3

	//------------------------------------
	//   search max 
	//------------------------------------
	dMax=dRed;
	uiMaxIndex=1;
	if(dMax<dGreen)
	{
		if(dGreen<dBlue){
			dMax=dBlue;
			uiMaxIndex=3;
		}
		else{
			dMax=dGreen;
			uiMaxIndex=2;
		}
	}
	else
	{
		if(dMax<dBlue)
		{
			dMax=dBlue;
			uiMaxIndex=3;
		}
	}

	//------------------------------------
	//   search min 
	//------------------------------------
	dMin=dRed;
	uiMinIndex = 1;
	if(dMin>dGreen)
	{
		if(dGreen>dBlue)
		{
			dMin=dBlue;
			uiMinIndex = 3;
		}
		else
		{
			dMin=dGreen;
			uiMinIndex = 2;
		}
	}
	else
	{ 
		if(dMin>dBlue)
		{
			dMin=dBlue;
			uiMinIndex = 3;
		}
	}

	//------------------------------------
	//   calc pp
	//------------------------------------
	dDiv = (dMax - dMin);
	dGetR = (dBlue - dGreen)*60/(dMax - dMin) +180;
	dGetG = (dRed  -  dBlue)*60/(dMax - dMin) +300;
	dGetB = (dGreen -  dRed)*60/(dMax - dMin) +60;

	//------------------------------------
	//  check gray
	//------------------------------------
	if( (uiRed==uiGreen)*(uiBlue==uiGreen))
	{
		uiFlagGray=1;
		*pdH=0;
	}
	else
	{
		switch (uiMinIndex)
		{
			case 1:
				*pdH = dGetR;
				break;
			case 2:
				*pdH = dGetG;
				break;
			case 3:
				*pdH = dGetB;
				break;
			default:
				*pdH=0;
				break;
		}
	}
	
	if(*pdH > 360){
		*pdH = *pdH - (double)(360*(int)(*pdH / 360));
		
	}

	if(*pdH < (-360)){
		*pdH = *pdH + (double)(360*(int)(*pdH / (-360)));
	}
	
	// *pdS = (dMax - dMin)/1; //cone model
	*pdS = (dMax - dMin)/dMax; //column model
	*pdV = dMax;

	return;
}