Mat QImage QPixmap互转

QImage MatToQImage(const cv::Mat& inMat)
{
    switch (inMat.type())
    {
    case CV_8UC4: 
    {
        QImage image(inMat.data,
            inMat.cols, inMat.rows,
            static_cast<int>(inMat.step),
            QImage::Format_ARGB32);
        return image;
    }
    case CV_8UC3:
    {
        QImage image(inMat.data,
            inMat.cols, inMat.rows,
            static_cast<int>(inMat.step),
            QImage::Format_RGB888);
        return image.rgbSwapped();
    }
    case CV_8UC1:// 8-bit, 1 channel
    {
#if QT_VERSION >= QT_VERSION_CHECK(5, 5, 0)
        QImage image(inMat.data,
            inMat.cols, inMat.rows,
            static_cast<int>(inMat.step),
            QImage::Format_Grayscale8); 
#else
        static QVector<QRgb>  sColorTable;
        // only create our color table the first time
        if (sColorTable.isEmpty())
        {
            sColorTable.resize(256);
            for (int i = 0; i < 256; ++i)
            {
                sColorTable[i] = qRgb(i, i, i);
            }
        }
        QImage image(inMat.data,
            inMat.cols, inMat.rows,
            static_cast<int>(inMat.step),
            QImage::Format_Indexed8);
        image.setColorTable(sColorTable);
#endif
        return image;
    }
    default:
        qWarning() << "error" << inMat.type();
        break;
    }
    return QImage();
}

//QImage 转 QPixmap
QImage image;
QPixmap map = QPixmap::fromImage(image);

//QPixmap 转 Mat
QPixmap image;
Mat frame = Mat(image.height(),image.width(),CV_8UC3,(void *)image.bits(),image.bytesPerLine()); 

//Mat 转 QImage
Mat frame;
QImage img=QImage((const unsigned char*)(frame.data),frame.cols,frame.rows,frame.step,QImage::Format_RGB888);