progress bar in QThreads

[jackajack01]

hello

I have an application that reads data from a file and with this data generates an image.

the problem is that on occasion takes up to a minute to generate the image due to the large volume of data in the file.

I would like to create a progress bar that tells the user what is missing to complete the picture.

Someone can give me an idea of ​​how to do that?

how do I grow the bar as progress is made in building the image?

[spirit]

See Keeping the GUI Responsive.

[amleto]

and http://doc.qt.io/qt-4.8/qprogressbar#value-prop