[HarfBuzz] Layout engine and vertical paragraphs

[eduardo]

Hi,

I'm very new to harfbuzz and i18n.

I'm started working with ICU which is huge, and I would like to know 
whether hb would be able to manage layouts in the same way ICU does.

Does it support vertical paragraph layouts?

Would I need to separate the text in different scripts or can I just 
provide harfbuzz with the full logical text and retrieve the visual one?

Where can I get some documentation or sample code to start learning hb? 
I have been looking Firefox4 and Skia codes, but I wonder whether there 
would be some smaller example.

Thanks a lot.

Eduardo.