After so much grappling with the scene, mouse events and painting, we correctly implemented the point entity in eCAD. Multiple points can be drawn in the scene which can then saved in an xml file and then the file can be loaded as well, resulting in the painting of point entities stored in the file.
Unlike the implementation we did initially, we did not have to make use of any signals to paint multiple point entities in the scene. Coming to the streaming of data, QXmlStreamReader and QXmlStreamWriter has been deployed to open and save an xml file respectively.
And yes, a different class has been improvised to create the graphics scene. Scene was implemented impromptuously previously. We have this innate feeling that now we are proceeding along the right track.