Qt resize image with best quality

c++ qt image-resizing qimage qpixmap
James Seva picture James Seva · Mar 26, 2014 · Viewed 12.9k times · Source

Can anyone help me resize an image in qt without making the image pixelated. Here's my code. the result is not as good as the original quality..thanks...

QImage img(name);
QPixmap pixmap;
pixmap = pixmap.fromImage(img.scaled(width,height,Qt::IgnoreAspectRatio,Qt::FastTransformation));
QFile file(folder+"/"+name);
file.open(QIODevice::WriteOnly);
pixmap.save(&file, "jpeg",100);
file.close();

Answer

Nejat picture Nejat · Mar 26, 2014

You have to pass Qt::SmoothTransformation transformation mode to the scaled function like:

QImage img(name);
QPixmap pixmap;
pixmap = pixmap.fromImage(img.scaled(width,height,Qt::IgnoreAspectRatio,Qt::SmoothTransformation));
QFile file(folder+"/"+name);
file.open(QIODevice::WriteOnly);
pixmap.save(&file, "jpeg",100);
file.close();

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