[Qt-interest] Best way to zoom an image

[Cole, Derek]

Hello,

I have created a label that is containing a Pixmap of an image that is much larger than the label, so I did some work to try to scale the image:

    QPixmap p(QPixmap::fromImage(*qi,Qt::AutoColor));
    QPixmap p1(p.scaled(ui->viewLabel->width(),ui->viewLabel->height(), Qt::KeepAspectRatio, Qt::SmoothTransformation ));
    ui->viewLabel->setPixmap(p1);
    ui->viewLabel->setFixedHeight(p1.height());
    ui->viewLabel->setFixedWidth(p1.width());

I guess my question is, if I wanted to get that pixmap p1 from the label, with something like "viewLabel->pixmap()", can I now scale that image back to its original size, or have I lost something with the compression to make the smaller image when I first scaled p1?

In other words, if I was to zoom "all the way in" on viewLabel's pixmap, would I then be able to zoom all the way back out and see my full, unaltered image?

If not, what is the best way to do this? I basically want to load my image, and then use the mouse wheel to zoom in and out on the image, always keeping the same level of image quality

Thanks

Derek
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