CODEWITHSUNDEEP
c++imageqtsavepng
Mary Dee
Mary Dee

Reputation: 5

Can't save PNG image into file

I have some troubles with image saving. I have to crop "1.png" by rect and save it to file, but an empty one is appearing (0 bytes). What am I doing wrong?

void RedactorForm::cropButtonSlot(int x1, int y1, int x2, int y2) {

    QImage pixmap("1.png");
    QRect rect(x1,y1,x2,y2);
    pixmap=pixmap.copy(rect);

    QString fileName("D:/yourFile.png");
    QFile file(fileName);
    file.open(QIODevice::WriteOnly);

    QDataStream out(&file);
    pixmap.save(fileName,0,100);
    out <<pixmap;
}

Upvotes: 0

Views: 4705

Answers (3)

mehmetfa
mehmetfa

Reputation: 311

I think you have to close the file which you opened before. Also you don't need to open the file at all. You can do that:

QRect rect(x1,y1,x2,y2);
QImage pixmap(x2-x1,y2-y1,QImage::Format_ARGB32);
pixmap.copy(rect);

QFile file("D:/yourFile.png");
pixmap.save(file.fileName(),"PNG");

Upvotes: 0

Evgeny
Evgeny

Reputation: 4010

You don't need use QDataStream for this task. Use directly save method of QImage. Your code should be like this:

QImage pixmap("1.png");

...................

QString fileName("D:/yourFile.png");
QFile file(fileName);
if(file.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
    pixmap.save(&file, "PNG");
}
else {
    qDebug() << "Can't open file: " << fileName;
}

Upvotes: 0

john elemans
john elemans

Reputation: 2666

QImage's save method does not take a file name as a parameter, it taske a QFile. Try this;

    pixmap.save(&file, "PNG");

Upvotes: 1

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