Qt 5 and OpenCV 4 Computer Vision Projects

Zooming in and out

OK. We have successfully displayed the image. Now, let's scale it. Here, we take zooming in as an example. With the experience from the preceding actions, we should have a clear idea as to how to do that. First, we declare a private slot, which is named zoomIn, and give its implementation as shown in the following code:

     void MainWindow::zoomIn()     {         imageView->scale(1.2, 1.2);     }

Easy, right? Just call the scale method of imageView with a scale rate for the width and a scale rate for the height. Then, we connect the triggered signal of zoomInAction to this slot in the createActions method of the MainWindow class:

     connect(zoomInAction, SIGNAL(triggered(bool)), this, SLOT(zoomIn()));

Compile and run the application, open an ...