// 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 #include 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