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<p>Simon,</p>
<p>When you say "JSTF axis" does that imply that one is building a
variable font? Or can this technique be applied to static fonts as
well?</p>
<p>Thanks, Bobby<br>
</p>
<div class="moz-cite-prefix">On 2024-02-22 07:59, Simon Cozens via
mpeg-otspec wrote:<br>
</div>
<blockquote type="cite"
cite="mid:87f9b17d-447c-4b51-baae-86ba3fa654e1@simon-cozens.org">When
Behdad, I and others did some thinking about the JSTF table last
year (with a view to potentially making a 2.0 version which
interacted better with variable fonts), we came to the realisation
that everything you can do with the JSTF table, you can actually
now do with a "JSTF" axis. So at this point it's entirely
redundant.
<br>
<br>
In fact, I think Behdad implemented JSTF-axis-based justification
in harfbuzz. (hb_shape_justify)
<br>
<br>
On 22/02/2024 14:49, nwillis--- via mpeg-otspec wrote:
<br>
<blockquote type="cite">The issue that always struck me about the
JSTF table definition is that there is no accompanying
justification engine against which you could measure whether or
not it works, partly works, or does not work. So it's a bit
"underanswerable." It would be like attempting to assess whether
there is enough detail in the GSUB/GPOS spec alone that you
could go implement HarfBuzz, Uniscribe, or any of the rest: to
implement one you definitely have to know more about the
behavior needed from a shaping engine than solely what's defined
in GSUB/GPOS ... but, conversely, you have to know more about
what the shaping engine is going to do in order to know whether
or not the GSUB/GPOS spec is well-written.
<br>
<br>
An interesting question might be to ask whether a JSTF table
could contain all of the info needed to work for some _known_
H&J engine — a particular TeX flavor, hz-program, or so on.
<br>
<br>
I never really found a detailed account of how JSTF made it into
the specification originally, such as describing whether it
seemed to be written to match some particular private
justification-engine's needs, or to match a hypothetical one
that may have never appeared on the market.
<br>
<br>
(If that info is out there, I'd certainly appreciate seeing it.)
<br>
<br>
Nate
<br>
<br>
---
<br>
<br>
<br>
On 2024-02-21 16:13, John Hudson via mpeg-otspec wrote:
<br>
<blockquote type="cite">Simon Cozens attempted an implementation
of JSTF table support a few
<br>
years ago, in an effort to find out whether it was actually
<br>
implementable. As I recall, he determined that much of it
could be
<br>
implemented, but that there were some holes or things that
could be
<br>
improved. As far as I know, there is no JSTF table support in
any
<br>
shipping software, which I guess at least means we wouldn’t
break
<br>
anything were we to revise the spec to produce something
workable for
<br>
CSS.
<br>
<br>
JH
<br>
<br>
<br>
On 2024-02-20 12:39 pm, Vladimir Levantovsky via mpeg-otspec
wrote:
<br>
<blockquote type="cite">The liaison statement I mentioned
during today's call can be found here:
<br>
<a class="moz-txt-link-freetext" href="https://lists.w3.org/Archives/Public/www-archive/2020Feb/att-0005/CSS-SC29-20200113.pdf">https://lists.w3.org/Archives/Public/www-archive/2020Feb/att-0005/CSS-SC29-20200113.pdf</a>
<br>
<br>
One of the aspects mentioned in the CSS WG statement is
related to using cursive elongation for text justification
purposes, which may be desirable for cursive writing and
could be essential e.g. for many Arabic scripts - I am
wondering if this can already be accomplished using JSTF
table, and whether the existing specification needs to be
updated to support it.
<br>
<br>
</blockquote>
</blockquote>
</blockquote>
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<br>
</blockquote>
<div class="moz-signature">-- <br>
Bobby de Vos<br>
<em><a class="moz-txt-link-abbreviated" href="mailto:bobby_devos@sil.org">bobby_devos@sil.org</a></em><br>
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