This app is just supposed to display what you see 
You can use the code from the application and re-use in other applications too.
I will soon work to integrate Harfbuzz library into app_server and probably extend BeOS API.
After that, you will be able to use that in Haiku applications and AFAIK for RTL support in Haiku we need to need to lot of changes(my initial idea for GSoC was to implement RTL in Haiku) but for now I can work on them after GSoC.