[HarfBuzz] [Fwd: Re: Harfbuzz-ng and Myanmar]

[Keith Stribley]

oops, forgot to cc list.

Hi Behdad,

Behdad Esfahbod wrote:
>> I'm not sure if the mask of 0xFF is correct, or whether it needs to be
>> tightened further to just the ignore flags.
>
> You're right.  It should only mask to the ignore flags, that is, 
> 0x0E.  Pushed to master.
Great thanks.

>
> Again, you are right.  This is planned to be fixed.  Should be done by 
> the end of next week (Jonathan Kew and I have a week-long HarfBuzz 
> hacking sprint in Toronto).
Sounds good.

>>
>> Has the process of porting the old harfbuzz shapers to harfbuzz-ng been
>> started, perhaps from Jonathan Kew? If so, where can I view it? Am I
>> right to assume that this will eventually replace the code in 
>> pango/modules?
>
> They will eventually replace code in pango/modules, yes.  Again, 
> should be in place by the end of next week.
Excellent, I'll take a look again in a couple of weeks.
>>
>> The SVGs above were generated with a utility that I use to compare
>> rendering between ICU, Harfbuzz and Graphite.
>> (http://scripts.sil.org/svn-public/graphite/grutils/trunk) I realise
>> that hb_shape is currently just a stub, but I was able to implement the
>> OT rendering by looking at basic_engine_shape,
>> _pango_ot_info_substitute, _pango_ot_info_position and apply_gpos_ltr.
>> The use of positions array from hb_buffer_get_glyph_positions was
>> probably the least intuitive, the other aspects were fine.
> d) Harfbuzz-ng interface
>
> Interesting.  Got code to share?
The code is in the above SVN repository. Copy the opentype directory 
from pango into the grsvg subdirectory if you want to build it, though I 
haven't yet updated it to your latest changes.
The harfbuzz-ng interface code is in:
http://scripts.sil.org/svn-public/graphite/grutils/trunk/grsvg/RenderHBNGLine.cpp

RenderHBNGLine::otShape() around line 116. It was written fairly quickly 
for standard features only and doesn't support RTL at the moment, so it 
may not be that useful to others.

Code to implement the callback functions using ICU for Unicode 
information is in
http://scripts.sil.org/svn-public/graphite/grutils/trunk/grsvg/harfbuzz-ng-external.c

I look forward to seeing the results of your work in Toronto,
cheers,
Keith