// Copyright (C) 2016 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#ifndef QRGB_H

#define QRGB_H

#include <QtGui/qtguiglobal.h>

#include <QtCore/qprocessordetection.h>

QT_BEGIN_NAMESPACE

typedef unsigned int QRgb;                        // RGB triplet

// non-namespaced Qt global variable

 inline constexpr QRgb RGB_MASK = 0x00ffffff;     // masks RGB values

inline constexpr int qRed(QRgb rgb)                     // get red part of RGB

{ return ((rgb >> 16) & 0xff); }

inline constexpr int qGreen(QRgb rgb)                   // get green part of RGB

{ return ((rgb >> 8) & 0xff); }

inline constexpr int qBlue(QRgb rgb)                    // get blue part of RGB

{ return (rgb & 0xff); }

inline constexpr int qAlpha(QRgb rgb)                   // get alpha part of RGBA

{ return rgb >> 24; }

inline constexpr QRgb qRgb(int r, int g, int b)         // set RGB value

{ return (0xffu << 24) | ((r & 0xffu) << 16) | ((g & 0xffu) << 8) | (b & 0xffu); }

inline constexpr QRgb qRgba(int r, int g, int b, int a) // set RGBA value

{ return ((a & 0xffu) << 24) | ((r & 0xffu) << 16) | ((g & 0xffu) << 8) | (b & 0xffu); }

inline constexpr int qGray(int r, int g, int b)         // convert R,G,B to gray 0..255

{ return (r*11+g*16+b*5)/32; }

inline constexpr int qGray(QRgb rgb)                    // convert RGB to gray 0..255

{ return qGray(qRed(rgb), qGreen(rgb), qBlue(rgb)); }

inline constexpr bool qIsGray(QRgb rgb)

{ return qRed(rgb) == qGreen(rgb) && qRed(rgb) == qBlue(rgb); }

inline constexpr QRgb qPremultiply(QRgb x)

{

    const uint a = qAlpha(x);

    uint t = (x & 0xff00ff) * a;

    t = (t + ((t >> 8) & 0xff00ff) + 0x800080) >> 8;

    t &= 0xff00ff;

    x = ((x >> 8) & 0xff) * a;

    x = (x + ((x >> 8) & 0xff) + 0x80);

    x &= 0xff00;

    return x | t | (a << 24);

}

Q_GUI_EXPORT extern const uint qt_inv_premul_factor[];

inline QRgb qUnpremultiply(QRgb p)

{

    const uint alpha = qAlpha(p);

    // Alpha 255 and 0 are the two most common values, which makes them beneficial to short-cut.

    if (alpha == 255)

        return p;

    if (alpha == 0)

        return 0;

    // (p*(0x00ff00ff/alpha)) >> 16 == (p*255)/alpha for all p and alpha <= 256.

    const uint invAlpha = qt_inv_premul_factor[alpha];

    // We add 0x8000 to get even rounding. The rounding also ensures that qPremultiply(qUnpremultiply(p)) == p for all p.

    return qRgba((qRed(p)*invAlpha + 0x8000)>>16, (qGreen(p)*invAlpha + 0x8000)>>16, (qBlue(p)*invAlpha + 0x8000)>>16, alpha);

}

QT_END_NAMESPACE

#endif // QRGB_H