编程语言之类型之间转换

末蓝、 2023-05-28 14:27 19阅读 0赞

## 1. QString转换String ##

string s = qstr.toStdString();

## 2.String转换QString ##

QString qstr2 = QString::fromStdString(s);

## 3.mat与qimage互转 ##

QImage cvMat2QImage(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.setNumColors(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)
        {
        
            // 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
        {
        
            return QImage();
        }
    }

## 4. QImage转Mat ##

Mat QImage2cvMat(QImage image)                          
    {
        
        Mat mat;
        switch (image.format())
        {
        
        case QImage::Format_ARGB32:
        case QImage::Format_RGB32:
        case QImage::Format_ARGB32_Premultiplied:
            mat = Mat(image.height(), image.width(), CV_8UC4, (void*)image.constBits(), image.bytesPerLine());
            break;
        case QImage::Format_RGB888:
            mat = Mat(image.height(), image.width(), CV_8UC3, (void*)image.constBits(), image.bytesPerLine());
            cv::cvtColor(mat, mat, CV_BGR2RGB);
            break;
        case QImage::Format_Indexed8:
            mat = Mat(image.height(), image.width(), CV_8UC1, (void*)image.constBits(), image.bytesPerLine());
            break;
        }
        return mat;
    }

## 5.QImage与QPixmap互转 ##

QPainter p(this);
        QPixmap pixmap;
        pixmap.load("../image/路飞.jpg");
     
        //QPixmap->QImage
        QImage tempImage = pixmap.toImage();
        p.drawImage(0,0,tempImage);
     
        QImage image;
        image.load("../image/路飞.jpg");
     
        //QImage->QPixmap
        QPixmap tempPixmap = QPixmap::fromImage(image);
        p.drawPixmap(450,0,tempPixmap);