RE: FVS Assignment for A

Hi Richard,

> 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>.
It should be same with <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.
It is defined as "isol" in the MVS model ds00.pdf which we discussed last month.

> 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.
Of cause not all of the glyph need encode, it can be decided by the contextual condition to select which glyph.
But we do need one glyph mapping in our font it. Otherwise it is useless.

What I am talking is we need this kind on mapping separately in the individual font or define it common to all 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?
After this forum complete and getting conclusion, I think the glyph set TR120 will be updated.
Actually, I have not seen TR170 yet. I think in this stage, we do not go to check if the glyph is in the set or not.
The Variant Form mapping rule is the core.

> 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.

I did not say I disagree it. but I don’t like this method. 
I think the Mongolian people will not use this method to develop font.
If you try to write the OpenType feature you will find the reason what I am saying. 

Just look one cooperation here:
1. Replacing final <BA, A> with < Final_BA_A glyph> one step

2.  Replace BA before A with the <Medial_BA_A glyph>
    Replace the A with the <Final_A> by context
    Replace <Final_A> after <Medial_BA_A glyph> with <Final_A_UNENCODED_2>

Which is simple and cheap?

Regards,


Jirimutu
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-----Original Message-----
From: Richard Wordingham [mailto:richard.wordingham@ntlworld.com] 
Sent: Sunday, August 9, 2015 7:04 PM
To: public-i18n-mongolian@w3.org
Subject: 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 15:17:29 UTC