saving QPixmap to QIODevice gives SEGV error

[sattu]

Hello all,

I am trying to capture a screenshot of my Application in a QPixmap and then save it to a QIODevice. But it's giving segmentation fault.
Not able to figure out why.

Here's the code-

QPixmap pix =  QPixmap::grabWindow(QApplication::desktop()->winId());
 
ui.myLabel->setPixmap(pix);  //This is fine. Displays the Screenshot
ui.myLabel->setScaledContents(true);
 
QByteArray bArray;
QBuffer buffer(&bArray);
buffer.open(QIODevice::WriteOnly);
 
        qDebug()<<"before";
        pix.save(&buffer);  //Gives SEGV Error
        qDebug()<<"after";
 
buffer.close();

QPixmap pix =  QPixmap::grabWindow(QApplication::desktop()->winId());

ui.myLabel->setPixmap(pix);  //This is fine. Displays the Screenshot
ui.myLabel->setScaledContents(true);

QByteArray bArray;
QBuffer buffer(&bArray);
buffer.open(QIODevice::WriteOnly);

        qDebug()<<"before";
        pix.save(&buffer);  //Gives SEGV Error
        qDebug()<<"after";

buffer.close();

To copy to clipboard, switch view to plain text mode 

Not able to figure out what the problem is.

[d_stranz]

You haven't given a format in the save() call. Try using something like "PNG" as the second parameter.

[sattu]

Try using something like "PNG" as the second parameter.

Thanks a lot. That solved the issue but now I am facing another issue.
After saving the image file in PNG format, I am trying to read the same file in another application and again save it in another name. (Extremely sorry if it sounds strange but please bear with me ) It's crashing.


The first app-

QPixmap pix =  QPixmap::grabWindow(QApplication::desktop()->winId());
 
    QImage img = pix.toImage();   //Converting to QImage so that I can know which format it is in.
 
    qDebug()<<"size: "<<img.size();
    qDebug()<<"format: "<<img.format();  //returns QImage::Format_RGB16
 
    img.save("/pefis/bin/test.png", "PNG");  //This works fine

QPixmap pix =  QPixmap::grabWindow(QApplication::desktop()->winId());

    QImage img = pix.toImage();   //Converting to QImage so that I can know which format it is in.

    qDebug()<<"size: "<<img.size();
    qDebug()<<"format: "<<img.format();  //returns QImage::Format_RGB16

    img.save("/pefis/bin/test.png", "PNG");  //This works fine

To copy to clipboard, switch view to plain text mode 

In another app-

QImage img("/pefis/bin/test.png", "PNG");
 
    qDebug()<<"size: "<<img.size();
    qDebug()<<"format: "<<img.format();  //returns QImage::Format_RGB32
 
    img.save("/pefis/bin/test1.png", "PNG");  //Crashes here. Gives SEGV Error

QImage img("/pefis/bin/test.png", "PNG");

    qDebug()<<"size: "<<img.size();
    qDebug()<<"format: "<<img.format();  //returns QImage::Format_RGB32

    img.save("/pefis/bin/test1.png", "PNG");  //Crashes here. Gives SEGV Error

To copy to clipboard, switch view to plain text mode 

First the Image format is automatically changing and then it is crashing when I am trying to save it in another name.
Please point out what mistake I am committing.


-Thanking You,
sattu