Your program, GanttProject, unfortunately doesn’t support the Arabic language in the PDF section; which lead the sentences in Arabic being unreadable.
English and many other languages’ writing systems start from left to write. While in Arabic language, the writing system does start from right to left, the opposite.
The PDF Export does start from left to right whatever language it is, this cause the Arabic characters to be disjointed and not connected together, and to be displayed in a reversed order which can only be readable from left to write, an English example: “raeppa sretcarahc cibarA eht woh si siht” => “this is how the Arabic characters appear”>
I hope you can fix this problem, we, in Saudi Arabia, use your program to study “Project Planning”, many student struggle with the language problem.