When exporting a project to PDF, the charts in the export are influenced by how large the application window is when you do the export. I kept getting the charts cropped, but when connecting my laptop to a larger (physical) screen and enlarging the application window, the charts in the pdf export is uncropped. This seems like an unnecessary feature…
AFAIK, to set the proper framing to the Gantt chart exported, I just collapse the tasks I do not need to get details, and just set the timeframe (start date and finish date). And the paper size (A3, usually; sometimes A2).
The scale of the monitor does not impact, I think.
Might be the font size or scaling of the font… but that is easy with the preview feature.
Hope this helps. Regars. M.