I have uploaded code for a simple Qt application that demonstrates how to make a simple layout using the library libavoid (written and maintained by Michael Wybrow, a member of MArVL: the Monash Adaptive Visualisation Lab at Monash University, Australia), which is part of the Adaptagram project. The code can be found here on Github. Libavoid provides fast connector routing around obstacles in a diagram. The application allows you to drag the boxes about the screen; the connecting lines are automatically routed by libavoid. The example was written on Windows 7, against Qt 5.7, using MinGW 5.3. The libavoid source is included in the repository.