I am using qwt library to draw graphs and then I need to generate images of these graphs, I want to put this part of the work into multithreading so that I can generate multiple images at the same time, then I refer to the official example given below:

I’m trying to install qwt 6.1.3 on Qt 6.7.0 and I have been following the installation guide at Qwt User’s Guide website, but whenever I try