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///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2003, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
//
// 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 Industrial Light & Magic 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,
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// 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.
//
///////////////////////////////////////////////////////////////////////////
#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
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