///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2003, Industrial Light & Magic, a division of Lucas

// Digital Ltd. LLC

// 

// All rights reserved.

// 

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///////////////////////////////////////////////////////////////////////////

#ifndef INCLUDED_IMF_CHROMATICITIES_H

#define INCLUDED_IMF_CHROMATICITIES_H

//-----------------------------------------------------------------------------

//

//	CIE (x,y) chromaticities, and conversions between

//	RGB tiples and CIE XYZ tristimulus values.

//

//-----------------------------------------------------------------------------

#include "ImathVec.h"

#include "ImathMatrix.h"

#include "ImfNamespace.h"

#include "ImfExport.h"

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER

struct IMF_EXPORT Chromaticities

{

    //-----------------------------------------------

    // The CIE x and y coordinates of the RGB triples

    // (1,0,0), (0,1,0), (0,0,1) and (1,1,1).

    //-----------------------------------------------

    IMATH_NAMESPACE::V2f	red;

    IMATH_NAMESPACE::V2f	green;

    IMATH_NAMESPACE::V2f	blue;

    IMATH_NAMESPACE::V2f	white;

    //--------------------------------------------

    // Default constructor produces chromaticities

    // according to Rec. ITU-R BT.709-3

    //--------------------------------------------

    Chromaticities (const IMATH_NAMESPACE::V2f &red   = IMATH_NAMESPACE::V2f (0.6400f, 0.3300f),

		    const IMATH_NAMESPACE::V2f &green = IMATH_NAMESPACE::V2f (0.3000f, 0.6000f),

		    const IMATH_NAMESPACE::V2f &blue  = IMATH_NAMESPACE::V2f (0.1500f, 0.0600f),

		    const IMATH_NAMESPACE::V2f &white = IMATH_NAMESPACE::V2f (0.3127f, 0.3290f));

    //---------

    // Equality

    //---------

    bool		operator == (const Chromaticities &v) const;    

    bool		operator != (const Chromaticities &v) const;

};

//

// Conversions between RGB and CIE XYZ

//

// RGB to XYZ:

//

// 	Given a set of chromaticities, c, and the luminance, Y, of the RGB

// 	triple (1,1,1), or "white", RGBtoXYZ(c,Y) computes a matrix, M, so

// 	that multiplying an RGB value, v, with M produces an equivalent

// 	XYZ value, w.  (w == v * M)

// 

// 	If we define that

// 

// 	   (Xr, Yr, Zr) == (1, 0, 0) * M

// 	   (Xg, Yg, Zg) == (0, 1, 0) * M

// 	   (Xb, Yb, Zb) == (0, 0, 1) * M

// 	   (Xw, Yw, Zw) == (1, 1, 1) * M,

// 

// 	then the following statements are true:

// 

// 	   Xr / (Xr + Yr + Zr) == c.red.x

// 	   Yr / (Xr + Yr + Zr) == c.red.y

// 

// 	   Xg / (Xg + Yg + Zg) == c.red.x

// 	   Yg / (Xg + Yg + Zg) == c.red.y

// 

// 	   Xb / (Xb + Yb + Zb) == c.red.x

// 	   Yb / (Xb + Yb + Zb) == c.red.y

// 

// 	   Xw / (Xw + Yw + Zw) == c.red.x

// 	   Yw / (Xw + Yw + Zw) == c.red.y

// 

// 	   Yw == Y.

// 

// XYZ to RGB:

// 

// 	YYZtoRGB(c,Y) returns RGBtoXYZ(c,Y).inverse().

// 

IMF_EXPORT IMATH_NAMESPACE::M44f    RGBtoXYZ (const Chromaticities chroma, float Y);

IMF_EXPORT IMATH_NAMESPACE::M44f    XYZtoRGB (const Chromaticities chroma, float Y);

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT

#endif