QRgb 学习

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#ifndef QRGB_H
#define QRGB_H

#include <QtCore/qglobal.h>

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

QT_MODULE(Gui)

typedef unsigned int QRgb; // RGB triplet

const QRgb RGB_MASK = 0x00ffffff; // masks RGB values

Q_GUI_EXPORT_INLINE int qRed(QRgb rgb) // get red part of RGB
{ return ((rgb >> 16) & 0xff); }

Q_GUI_EXPORT_INLINE int qGreen(QRgb rgb) // get green part of RGB
{ return ((rgb >> 8) & 0xff); }

Q_GUI_EXPORT_INLINE int qBlue(QRgb rgb) // get blue part of RGB
{ return (rgb & 0xff); }

Q_GUI_EXPORT_INLINE int qAlpha(QRgb rgb) // get alpha part of RGBA
{ return rgb >> 24; }

Q_GUI_EXPORT_INLINE QRgb qRgb(int r, int g, int b)// set RGB value
{ return (0xffu << 24) | ((r & 0xff) << 16) | ((g & 0xff) << 8) | (b & 0xff); }

Q_GUI_EXPORT_INLINE QRgb qRgba(int r, int g, int b, int a)// set RGBA value
{ return ((a & 0xff) << 24) | ((r & 0xff) << 16) | ((g & 0xff) << 8) | (b & 0xff); }

Q_GUI_EXPORT_INLINE int qGray(int r, int g, int b)// convert R,G,B to gray 0..255
{ return (r*11+g*16+b*5)/32; }

Q_GUI_EXPORT_INLINE int qGray(QRgb rgb) // convert RGB to gray 0..255
{ return qGray(qRed(rgb), qGreen(rgb), qBlue(rgb)); }

Q_GUI_EXPORT_INLINE bool qIsGray(QRgb rgb)
{ return qRed(rgb) == qGreen(rgb) && qRed(rgb) == qBlue(rgb); }

QT_END_NAMESPACE

QT_END_HEADER

#endif // QRGB_H