Re: [ft-devel] A question about freetype and harfbuzz

[Behdad Esfahbod]

On Mon, 2007-05-28 at 02:34 -0400, address@hidden wrote:
> On Mon, 28 May 2007 13:48:20 +0800
> LingNing Zhang <address@hidden> wrote:
> 
> >Hi all,
> >I have a question about freetype and harfbuzz.
> >FreeType1 includes an extension to support OpenType text layout 
> >processing. But this support hasn't become part of FreeType2. Why?
> >Why does FreeType2 not use the codes of harfbuzz to support OpenType 
> >text layout processing?
> >Thanks!
> 
> # Personally, I'm one of the people who want FT2 to have
> # support for text layout feature. I guess I feel sympathy
> # with you. But we are minority among FT2 developers :-).
> 
> Excuse me, HarfBuzz developers want FT2 to include
> built-in OT table parsers? Or, there is non-ICU/
> non-HarfBuzz/non-M17NLib/non-Pango/non-Qt library
> their developers want FT2 to have OT table parser
> and don't want to copy such from existing libraries?

No, no HarfBuzz developer wants that.  The future is clear: HarfBuzz is
the Linux OpenType Layout engine that Pango, Qt, and ICU will use.  I'm
currently in the process of (slowly) rewriting it to use mmap()ed font
files instead of reading tables into memory.  When I'm done with that,
I'll revise the API and freeze it.

There is further work to make HarfBuzz *the* shaper API for Linux
systems.  That is, again, Pango, Qt, ICU, Scribus, OO.o, etc all will be
using HarfBuzz.  This has been discussed extensively at the Text Layout
Summit in Boston, and discussion is going on on the harfbuzz list and
will be at the next Text Layout Summit at aKademy in a few weeks.

This all probably takes a year or two to stabilize and released as a
shared library, but what is two years anyway...


On Mon, 2007-05-28 at 02:42 -0400, Werner LEMBERG wrote:
> Perhaps a misunderstanding: I don't object to make FreeType handle
> OpenType tables (see the validating stuff which we have developed
> together).  However, I object to let FreeType interpret them -- this
> is really the job of a higher-level library. 

For the record, I think the ftvalid stuff is misplaced and doesn't
belong in FreeType.  Some of my concerns are similar to what David
already raised.  In short, I believe that any OpenType Layout engine
should do its own validation, and has enough code to be able to do a
validator very easily, and if mere font validation is desired, things
like ttx already do it.  I don't see where ftvalid is expected to be
used. (that said, given that it's already in freetype, I don't mind it
staying there.)


Regards,


-- 
behdad
http://behdad.org/

"Those who would give up Essential Liberty to purchase a little
 Temporary Safety, deserve neither Liberty nor Safety."
        -- Benjamin Franklin, 1759