[HarfBuzz] Harfbuzz and Skia

[Jarek M]

Hi.

I'm working on a project that uses an older, modified webkit version - all running on QNX. This webkit version uses modified skia to render graphics.

Recently, I ran into a little challenge. This version of WebKit does not support arabic fonts and overall RTL languages. I integrated fribidi (called it within TextRun class) to process the text. Things got better, the arabic fonts got mirrored and combined RTL into words, and the words RTL into sentences. The resulting text got drawn using Skia.  However, the sentences still look like they are left justified. The spacing between the words is incorrect or at least not the same when compared to safari or firefox. 

So, I am wondering where is the problem. I understand fribidi is used to perform text preprocessing (with a bidirectional algorithm). Does fribidi take care of spacing?  Harfbuzz is an entire font shaping stack. Doest it take care of bidirectional text?  

What would You recommend to use in case described? Fribidi + simply writing the buffer using TextRun and somehow figuring out why is the sentence not properly aligned or skip fribidi and use harfbuzz + skia? In that case, do I need additional tools to use harfbuzz and skia together on QNX ?  (freefont etc). I managed to compile harfbuzz to run on QNX however, I am not sure if I need to use it in a first place. Well, if You have some suggestions appreciated. I'm getting familiar with the webkit source, I see already that the version I'm using is quite different, plenty of rewritten code.  

Kind Regards,
Jarek