Hi Adam,
Greeting from Syncfusion.
Currently we don’t have support to export Gantt as PDF file. We have already logged a feature request for this. You can track its status from below feedback link.
Currently we are working on this, it will be implemented and included in our upcoming Volume 4, 2019 main release which is expected to be rolled out in December 2019.
Until then we appreciate your patience.
Regards,
Gurunathan