How to convert QPixmap to base64 QString in Qt?

sigmind

I am using QT 5.7 for a program where I have to convert a QPixmap to base64 QString format. I have tried to first convert the QPixmap to cv::Mat and then added my existing conversion flow.

cv::Mat pixData(pix.rows(),pix.cols(),CV_8UC3,pix.scanline());
            std::vector<uchar> IMbuffer;
          //  std::vector<uint8_t> IMbuffer;
            cv::imencode(".png", pixData, IMbuffer);
            QByteArray byteArray = QByteArray::fromRawData((const char*)IMbuffer.data(), IMbuffer.size());
            QString base64Image(byteArray.toBase64());

But it returns error:

error: 'class QPixmap' has no member named 'rows'
    cv::Mat pixData(pix.rows(),pix.cols(),CV_8UC3,pix.scanline());
                        ^

So it is clear that such conversion from QPixmap to cv::Mat is incompatible. So is there any easy way to convert QPixmap to base64 QString?

SGaist

Hi,

QPixmap::size is likely what you are looking for.

But there's no need to have OpenCV involved. Take a look at QPixmap::save

sigmind

@SGaist
I have tried from here

QPixmap pix;
QImage image = pix.toImage();
 QByteArray byteArray;

 QBuffer buffer(&byteArray);

    image.save(&buffer, "JPEG"); // writes the image in JPEG format inside the buffer

    QString iconBase64 = QString::fromLatin1(byteArray.toBase64().data());

But it returns:

 error: 'QBuffer' was not declared in this scope
            QBuffer buff(&byteArray);
            ^

JKSH

@sigmind said in How to convert QPixmap to base64 QString in Qt?:

 error: 'QBuffer' was not declared in this scope
            QBuffer buff(&byteArray);
            ^

Your compiler is telling you that you need to #include the QBuffer header.

QPixmap pix;
QImage image = pix.toImage();
QByteArray byteArray;
QBuffer buffer(&byteArray);

Why not use @SGaist's suggestion? QPixmap::save()