[HarfBuzz] Skipping Control for Attaching Marks using OpenType

[Richard Wordingham]

On Mon, 17 Jun 2013 07:43:52 +1000
Andrew Cunningham <lang.support at gmail.com> wrote:

> Hi Richard,
> 
> I don't know what OT featurez you are using in your font, but Tai Tham
> would be an undefined script in Unis ribe so it would need to limit
> itself to features fhat can be used by default shaper.
> 
> Essentially, rlig, mark, mkmk, optionally liga and clig.
> 
> If your font is using anyother feature fod Tai Tham rendering yoh
> will not get what you expect.

My font is currently being set up to work with a Tai Tham shaper.
Other OpenType environments will be added later if I can work out how.
Graphite will be added at some stage.  I am currently using blwf,
pstf, abvs and blws features, which I didn't expect to see working on
Windows 7 for Tai Tham.  I have set up detectors in the font to perform
specific contractions if any of the these or the ccmp, liga, clig, or,
after providing a copy to Behdad, rlig, features is enabled. The blwf
and pstf detectors are broken.

The only application on Windows 7 Service Pack 1 that triggered was
Firefox 19.0.2 (I don't use Windows much), which triggered the
detectors for clig, rlig, abvs and blws.  It gave the same results for
the test sequence I have just provided as HarfBuzz 0.9.18; however, I
believe it is using HarfBuzz despite being on Windows.

In particular, Internet Explorer 9, Notepad, Word 2002, SIL FieldWorks
6.0 and OpenOffice 3.3 did not enable any of ccmp, liga, clig and rlig.

Richard.