How to convert QPixmap to base64 QString in Qt?

Question

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.

Qpixmap pix;
cv::Mat pixData(pix.rows(),pix.cols(),CV_8UC3,pix.scanline());
                std::vector<uchar> 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?

score 5 · Accepted Answer · answered Nov 07 '18 at 23:31

5

Try this;

 QBuffer buffer;
 buffer.open(QIODevice::WriteOnly);
 pix.save(&buffer, "PNG");
 auto const encoded = buffer.data().toBase64();

answered Nov 07 '18 at 23:31

john elemans

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It says "error: 'QBuffer' was not declared in this scope QBuffer buffer; " Which header should be insluded for QBuffer? ^ – nocturnal_abu Nov 07 '18 at 23:40
@nocturnal_abu use `#include ` – eyllanesc Nov 07 '18 at 23:44
Adding #include compiles and works like a charm. Thanks a lot. – nocturnal_abu Nov 07 '18 at 23:47

How to convert QPixmap to base64 QString in Qt?

1 Answers1