QT QImage 与 Opencv的Mat 之间互转

1、QImage 转 Mat

cv::Mat QImageToMat(QImage image)
{
	cv::Mat mat;
	switch (image.format())
	{
	case QImage::Format_ARGB32:
	case QImage::Format_RGB32:
	case QImage::Format_ARGB32_Premultiplied:
		mat = cv::Mat(image.height(), image.width(), CV_8UC4, (void*)image.constBits(), image.bytesPerLine());
		break;
	case QImage::Format_RGB888:
		mat = cv::Mat(image.height(), image.width(), CV_8UC3, (void*)image.constBits(), image.bytesPerLine());
		cv::cvtColor(mat, mat, CV_BGR2RGB);
		break;
	case QImage::Format_Indexed8:
		mat = cv::Mat(image.height(), image.width(), CV_8UC1, (void*)image.constBits(), image.bytesPerLine());
		break;
	}
	return mat;
}

2、Mat 转 QImage

QImage MatToQImage(const cv::Mat& mat)  
{  
    // 8-bits unsigned, NO. OF CHANNELS = 1  
    if(mat.type() == CV_8UC1)  
    {  
        QImage image(mat.cols, mat.rows, QImage::Format_Indexed8);  
        // Set the color table (used to translate colour indexes to qRgb values)  
        image.setColorCount(256);  
        for(int i = 0; i < 256; i++)  
        {  
            image.setColor(i, qRgb(i, i, i));  
        }  
        // Copy input Mat  
        uchar *pSrc = mat.data;  
        for(int row = 0; row < mat.rows; row ++)  
        {  
            uchar *pDest = image.scanLine(row);  
            memcpy(pDest, pSrc, mat.cols);  
            pSrc += mat.step;  
        }  
        return image;  
    }  
    // 8-bits unsigned, NO. OF CHANNELS = 3  
    else if(mat.type() == CV_8UC3)  
    {  
        // Copy input Mat  
        const uchar *pSrc = (const uchar*)mat.data;  
        // Create QImage with same dimensions as input Mat  
        QImage image(pSrc, mat.cols, mat.rows, mat.step, QImage::Format_RGB888);  
        return image.rgbSwapped();  
    }  
    else if(mat.type() == CV_8UC4)  
    {  
        qDebug() << "CV_8UC4";  
        // Copy input Mat  
        const uchar *pSrc = (const uchar*)mat.data;  
        // Create QImage with same dimensions as input Mat  
        QImage image(pSrc, mat.cols, mat.rows, mat.step, QImage::Format_ARGB32);  
        return image.copy();  
    }  
    else  
    {  
        qDebug() << "ERROR: Mat could not be converted to QImage.";  
        return QImage();  
    }  
}