Re: FVS Assignment for A

On Sun, 9 Aug 2015 09:11:39 +0900
<jrmt@almas.co.jp> wrote:

> Resending with attached file.   
> 
> Hi Rechard,
> 
> > Why do you think that the final glyph in
> > https://lists.w3.org/Archives/Public/public-i18n-mongolian/2015JulSep/att-0221/A_F_FVS2.png
> >has anything to do with MVS?  It is clearly designed to attach to
> >another glyph.  
> > It appears to be a form of final A and E used directly after BA,
> > PA, feminine QA, feminine GA, FA, KA, KHA, and in some of the other
> > writing systems. 
> Yes you are right on the understanding, the final A/E comes after BA
> PA, it is directly connected and loop toward left site. but we look
> the A/E included the tooth of the final part of the BA-A/E, PA-A/E.
> please see red bordered final BA-A in the attached file.
> 
> If we directly connect the final A/E after BA, PA, it is become like
> this. ᠪ᠊ᠠ᠋ ᠫ᠊ᠠ᠋ If we see the final part of the final BA-A/E, PA-A/E
> is the final A/E itself directly. It will become BA-A-A or BA-E-E,
> refer the red rectangle circled part in the attached file.
> 
> > You can see it in context at
> > http://www.studymongolian.net/lessons/basics/writing/ , and both
> > TR170 and the Quejingzhabu's document show examples. If you need to
> > display it in isolation, it is already doubly encoded - <ZWJ, A,
> > FVS1> and <ZWJ, E, FVS1>.

> Currently encoded final A/E is the form have bubbled head, after MVS
> and ZWJ. We need the directly connectable form.

We have a formal problem here.  How should <NA, A, NA, MVS, A, FVS1> be
rendered?  One might naively expect it to be rendered the same as <NA,
A, NA, MVS, A>.

Reportedly, Uniscribe/DirectWrite applies the init feature to the A in
<MVS, A>.  This is completely illogical!  It should apply the isol
feature rather than the init feature!  Arguably, MVS should be
classified as left-joining (sic), i.e. connecting to the following
character.  This should then result in the fina feature being applied.

There is nothing to stop a font applying the changes of the fina feature
to the A in <MVS, A> under a different feature, though depending on the
font compilation tool one may have to copy substitution definitions.
As AAT fonts have to implement the rules for applying isol, init, medi
and fina themselves, this is probably not a significant issue for them.

This relates to my encoding claim.  I was wrong; I was thinking that
the post-MVS form was 'isolated' rather than 'connected'.  There is
currently no encoding for it.

> Please find attached file and check the which is better encoding it
> as F+FVS2 ?, or use ligature?

I hope you will agree that not every glyph needs an encoding, not
even in in the PUA.  It is not unknown for Chinese characters to be
decomposed to multiple characters to ease the task of creating the font.

Moreover, a font that used the glyph set from TR170 would not be able
to display this unencoded glyph as something distinct from the
free-standing post-MVS A.  Should one therefore regard such a font as
deficient?

I therefore do not understand your question.  It appears that the font
in the tables at http://www.studymongolian.net/lessons/basics/writing/
represents final (non-isolated) <BA, A> by using the glyph for medial
<BA, A> followed by this glyph you wish to encode.  I see nothing
wrong with doing it this way.  One may prefer to use a ligature for
each of final (non-isolated) <BA, A> and the similar combinations.  The
choice is the font maker's.

Richard.

Received on Sunday, 9 August 2015 10:04:14 UTC