//**************************************************************************
//  FILENAME	:   RGBToClut.hpp
//
//  CLASSES		:   RGBToClut
//
//  DESCRIPTION	:   Convert an RGB image into an 8 bit indexed image
//		            with a specific Color LookUp Table
//
// ECOMPACS DICOM Network Transport Libraries * Version 0.1 Beta
//**************************************************************************

#ifndef	_RGBTOCLUT_
#define	_RGBTOCLUT_


//**************************************************************************
//          CONSTANTS  -  ENUMERATED TYPES
//**************************************************************************


enum teClutSelect {fixedClut, popularity, mediancut};

struct mycol
{
	long	nb;

	int		r;
	int		g;
	int		b;
};


//**************************************************************************
//          class RGBToClut
//**************************************************************************
class RGBToClut
{
private:
	BOOL			RGBPixmaps;	// RGB image is composed by 3 separate pixmaps

	unsigned char	* Pix; 		// 8 bit indexed image
	unsigned char	* Rgb; 		// 8 bit RGB image
	unsigned char	* Red; 		// 8 bit Red channel
	unsigned char	* Green;	// 8 bit Green channel
	unsigned char	* Blue; 	// 8 bit Blue channel

	RGBQUAD			* Colors;
	int 			Width;
	int 			Height;

	short			*Histo;
	long			NbCol;	// number of colors in the histogram

public:
	 RGBToClut ();
	~RGBToClut ();

	//**************************************************************************
	// Purpose: the 3 RGB channels are mixed in the same buffer
	//          histo indicates if the color histogram must be compiled
	//          this parameter allows to take into account several images
	//          to compute the histogram which will be used to generate the color palette
	//**************************************************************************
	void SetRGBImage (	unsigned char	* image,
						int				width,
						int				height,
						BOOL			histo = TRUE);

	//**************************************************************************
	// Purpose: the 3 RGB channels are separated
	//          histo indicates if the color histogram must be compiled
	//          this parameter allows to take into account several images
	//          to compute the histogram which will be used to generate the color palette
	//**************************************************************************
	void SetRGBImage (	unsigned char	* RChannel,
  						unsigned char	* GChannel,
  						unsigned char	* BChannel,
  						int				width,
						int				height,
  						BOOL			histo = TRUE);

	//**************************************************************************
	// Purpose: compute the indexed image according to the various parameters
	//          image and myClut must have been allocated
	//          return 0 if everything OK
	//**************************************************************************
	int ComputeIndexedImage(unsigned char	* image,
							RGBQUAD			* Colors,
							teClutSelect	method = popularity);

private:
	void ComputeHistogram ();		// compute the histogram of the image

	void ConvertRGBToIndexed ();	// convert the RGB image into an 8 bit indexed image

	void Popularity ();				// select colors according to their popularity

	void MedianCut ();				// select palette colors according to the median cut algorithm

	void UpdatePaletteHisto ();		// try to put palette colors in an acceptable order

	void InitHisto (short val);		// initialize histogram with val

	void InitClut (int val);		// initialize clut with val

	short MatchColor (int r, int g, int b);	// find the best indexed color for an RGB entry
};

#endif