Re: [ft-devel] Getting the kerning pairs in under O(n*n)

[Adam Twardoch (List)]

The makers of m17n developed libotf which at a time provide some,
although rather spotty, support for complex-script rendering.

The OpenType Layout model is such that -- especially for Indic scripts
-- an OpenType Layout engine (a library) must "know a lot" and interact
well with OpenType fonts. The "knowledge" about the correct orthographic
and typographic text layout in a number of Asian scripts is split
between the OpenType Layout engine and OpenType fonts. The correct text
layout is only possible in combination of these two.

The FreeType project once started a sub-project called FreeType Layout,
which was aiming to develop an OpenType Layout engine that would match
the "reference implementation", which is the Microsoft Uniscribe library
on Windows. However, the FreeType developers found that they were not
"the right people" to do that, so the project stalled.

Then, the m17n developers created libotf. 

However, the FreeType Layout library was then forked into two separate
OpenType Layout engines, one as part of Qt, the other as Pango, or
something like that. Then, the projects were merged again, which
resulted in HarfBuzz. And then, HarfBuzz was rewritten from scratch,
which resulted in "HarfBuzz-ng", which is now the current HarfBuzz.

Independently of all that, IBM has developed the ICU Layout library as
part of the ICU project, with a similar goal. More recently, the ICU
Layout library was essentially "abandoned" but valuable portions of it
were ported to HarfBuzz. Before 2011, ICU Layout was considered
"stable", and possibly the best solution for an opensource OpenType
Layout library, while HarfBuzz was undergoing very dynamic rewrites. But
in 2012, I believe that HarfBuzz has matched and surpassed ICU Layout.

So it all did start with FreeType after all. HarfBuzz stemmed from it,
went a complicated path, and arrived at where it is now -- which is
*good shape* already. ICU Layout is probably second choice, while other
solutions such as libotf are no longer developed and I wouldn't invest
into them.

Regards,
Adam

On 12-10-04 02:41, address@hidden wrote:
> Hi,
>
> On Wed, Oct 03, 2012 at 02:38:40PM -0700, Vinnie Falco wrote:
>
>>> Please don't forget that FreeType's job is to render glyphs, nothing
>>> else.
>> My opinion is that since FreeType opens the font file, it might as
>> well process everything that is in it.
> Might the suggestion that FreeType could perhaps /parse and expose/ all tables
> without necessarily /handling/ all of them, help in this discussion? 
>
> Analogous to Adam's audio/video example, could it make sense for FreeType to
> implement the audio/video demuxers (table parsers) and the video codecs (glyph
> rendering), but not the audio codecs (text layout)?
>
> (Something else: in this and similar discussions I don't hear anyone 
> mentioning
> m17nlib for text layout, even though it aims to handle all aspects of all
> current unicode scripts. I've also found its API for that quite nice and
> elegant a few years ago. When it's mentioned, it's mostly in the context of
> multilingual input alone. Does it have pronounced disadvantages compared to
> Harfbuzz or Pango that I'm missing?)
>
> Kind regards,
>
>
> Emile.
>


-- 

May success attend your efforts,
-- Adam Twardoch
(Remove "list." from e-mail address to contact me directly.)