QConcurrent and images added onscreen

Hello,

i'm reading the tutorial about QConcurrent in the doc, i am not sure to understand something: the QLabel is added to the layout, and then we launch the concurrent function to scale the images :

http://doc.qt.nokia.com/4.7/qtconcur...aling-cpp.html

Code:

---

int dim = sqrt(qreal(files.count())) + 1;
     for (int i = 0; i < dim; ++i) {
         for (int j = 0; j < dim; ++j) {
             QLabel *imageLabel = new QLabel;
             imageLabel->setFixedSize(imageSize,imageSize);
             imagesLayout->addWidget(imageLabel,i,j);
             labels.append(imageLabel);
         }
     }
 
     // Use mapped to run the thread safe scale function on the files.
     imageScaling->setFuture(QtConcurrent::mapped(files, scale));

---

unless i'm missing something in the code, it seems that the asynchronous function scale the images only after they are onscreen. So i am not sure to understand where i'm wrong.

Thanks for your help