Sorry, I guess not all mailers handle embedded graphics in HTML messages. I
posted it so that you could see the graphics, on
http://www.macchiato.com/utc/variation_selection/variation_selection_followu
p.htm
It is *not* exactly the same. I added and rearranged the concrete examples
at the very end. I think those last examples of the font are key to this
issue: depending on which we say conformantly support the variation sequence
will help determine how we handle this issue.
I also posted my previous paper, although my thinking has changed a bit
since then, particularly on the 'tightness' of the description -- the
paragraph containing "Suppose a glyph has a slash with an angle of 32° from
vertical."
http://www.macchiato.com/utc/variation_selection/variation_selection.htm
Mark
—————
Πόλλ’ ἠπίστατο ἔργα, κακῶς δ’ ἠπίστατο πάντα — Ὁμήρου Μαργίτῃ
[For transliteration, see http://oss.software.ibm.com/cgi-bin/icu/tr]
----- Original Message -----
From: "Asmus Freytag" <asmusf@ix.netcom.com>
To: "Mark Davis (jtcsv)" <mark.davis@jtcsv.com>
Sent: Sunday, January 27, 2002 01:36
Subject: Re: Variation Selection (Was Re: Unicode 3.2: BETA files updated)
Now this message was clear as mud. Literally. As in totally opaque in the
pure visual sense: All the examples show as nice gray boxes in my mailer -
please make sure whatever you are sending is an attachment, and not in-line.
Thanks,
A./
(PS: They may well arrive in viewable condition when this reply gets back
to you..., but I can't read it)
—————
Πόλλ’ ἠπίστατο ἔργα, κακῶς δ’ ἠπίστατο πάντα — Ὁμήρου Μαργίτῃ
[For transliteration, see http://oss.software.ibm.com/cgi-bin/icu/tr]
----- Original Message -----
From: "Asmus Freytag" <asmusf@ix.netcom.com>
To: "Mark Davis (jtcsv)" <mark.davis@jtcsv.com>
Sent: Sunday, January 27, 2002 01:36
Subject: Re: Variation Selection (Was Re: Unicode 3.2: BETA files updated)
Now this message was clear as mud. Literally. As in totally opaque in the
pure visual sense: All the examples show as nice gray boxes in my mailer -
please make sure whatever you are sending is an attachment, and not in-line.
Thanks,
A./
(PS: They may well arrive in viewable condition when this reply gets back
to you..., but I can't read it)
At 12:33 AM 1/27/02 -0800, you wrote:
>
>
> > >The other possibility is to say that to be strictly Unicode-conformant,
> > >fonts should always use the reference glyph for unmarked characters
> > >(ignoring differences only of style). I think this is actually a better
> >
> > Boy, great minds to think alike. Mark Davis just proposed that in
> > a paper to the UTC this week.
>
>I would like to thank you for the compliment, but I must not have been
>clear in my paper, since that is not really what I was proposing. Let me
>try again, with a concrete case.
>
>Since I don't have a variety of math fonts, I will use the example of
>U+03B8 greek small letter theta. This character can be represented by the
>following glyphs (collected on my system) and many more. Any of these are
>acceptable, conformant representations of the theta, depending on the
>design of the font.
>
>1f908bf2.jpg
>
>Now, there is already a presentation form for the "open" form of the
>theta, at U+03D1 greek theta Symbol. A presentation form of a character
>represents the same abstract character, but is restricted in format to a
>subset of the possible glyphs that could represent the character, such as
>the following:
>
>1f908db5.jpg
>
>But suppose there were no such character. In that case, we might add an
>encoded variant, expressed as an entry in the StandardizedVariants.html
>file in the UCD, looking something like:
>Ref Glyph Character Sequence Alt Glyph Description of variant appearance
>1f908e05.jpg 03B8, FE00 1f908e4b.jpg Open Theta, unconnected on the left
side
>
>Now there are four key facts that we need to keep in mind:
> * This does not, at all, prevent the character alone <U+03B8> from
> having the same appearance as what is titled as the Alt Glyph. It is
> still a perfectly acceptable representation of that character in normal
text.
> * What is titled Alt Glyph in this entry is also merely a
> representative, one of many possible glyphs that can represent the
> variant. Thus both of the glyphs are "representative": they do not, and
> cannot, encompass all of the possible glyphs that can represent either
> the character alone, or the variant. (It would be a good idea for us to
> change the title of this column, since it may mislead some into thinking
> that that precise glyph must be used: it should be Variant Ref Glyph.)
> * A key feature of the entry is the description; it provides the
> limitation on the set of glyphs that can be used to represent the
> sequence, if the sequence is supported by a font.
> * If a font does not support the variation sequence given by this
> entry, that it is also perfectly acceptable to ignore the U+FE00, and
> thus render the sequence <U+03B8, U+FE00> with precisely the same glyph
> as the single character <U+03B8>.
>So the open issue is: how do we specify variation selection in the Unicode
>Standard such that people can make a distinction between <U+03B8, U+FE00>
>and <U+03B8>?
>
>I could see two possible alternatives.
>>(a) Add an explicit entry to StandardizedVariants.html, looking like the
>>following:
>>Ref Glyph Character Sequence Alt Glyph Description of variant appearance
>>1f908e69.jpg 03B8, FE01 1f908ea5.jpg Closed Theta, connected on the left
side
>>(Where I differed from Asmus is he felt that we could reserve a VS for
>>this purpose, without supplying an explicit entry describing the
>>limitation on the possible glyphs. One could conceivably take it to be
>>the negation of each of the descriptions of variants of that character.)
>>
>>(b) Make it clear that a font supports a variation selection sequence if
>>and only if it provides a visual distinction between the character alone
>>vs. the character followed by a variation selector; and that the visual
>>distinction is based on the description of the variant appearance in the
entry.
>>
>>This also goes for multiple sequences: if a font supports <X, VS1> and
>><X, VS2>, then it must visually distinguish all three sequences: <X>, <X,
>>VS1>, and <X, VS2>; and the distinction must be in accordance with the
>>given descriptions.
>>
>>While I think that either of these two approaches are acceptable, I find
>>myself currently leaning towards the second. I find it fairly pointless
>>to say that a font "supports" the variation selection sequence <U+03B8,
>>U+FE00> if it does not provide a visual distinction from <U+03B8>; and
>>such a distinction should be based on the entry description. Thus, of the
>>following four fonts, only number 4 correctly supports the sequence
>><U+03B8, U+FE00>. (Of course, any real font would have designs for the
>>two glyphs that were a bit more harmonious!)
>>Font <U+03B8> <U+03B8, U+FE00>
>>1 1f908ec3.jpg 1f908ee1.jpg
>>2 1f908ef5.jpg 1f908f31.jpg
>>3 1f908f6d.jpg 1f908f8b.jpg
>>4 1f908faa.jpg 1f908ff0.jpg
>>
>>Mark
>>
>>â?"â?"â?"â?"â?"
>>
>>Î ÏOλλâ?T á¼ Ï?ίÏfÏ"αÏ"ο á¼"Ïγα, κακῶÏ, δâ?T á¼
>>Ï?ίÏfÏ"αÏ"ο Ï?άνÏ"α â?" á½?μήÏοÏ. ÎoαÏγίÏ"á¿f
>>[For transliteration, see
>><http://oss.software.ibm.com/cgi-bin/icu/tr>http://oss.software.ibm.com/cg
>>i-bin/icu/tr]
>>
>>http://www.macchiato.com
>>----- Original Message -----
>>From: "Asmus Freytag" <<mailto:asmusf@ix.netcom.com>asmusf@ix.netcom.com>
>>To: "David Hopwood"
>><<mailto:david.hopwood@zetnet.co.uk>david.hopwood@zetnet.co.uk>;
>><<mailto:unicode@unicode.org>unicode@unicode.org>
>>Sent: Friday, January 25, 2002 22:37
>>Subject: Re: Unicode 3.2: BETA files updated
>>
>> > At 10:58 PM 1/24/02 +0000, David Hopwood wrote:
>> > >One possibility is to make VS1 specify what is now the reference
glyph,
>> > >and VS2 specify the alternate glyph. Unmarked would mean either.
>> >
>> > Boy, great minds do think alike. I proposed that in a paper to the UTC
>> > last year. ;-)
>> >
>> > You realize that this issue is not limited to variation selectors?
>> > Read the section on greek phi in
>> <http://www.unicode.org/unicode/reports/tr28>http://www.unicode.org/unico
>> de/reports/tr28
>> >
>> > >The other possibility is to say that to be strictly
Unicode-conformant,
>> > >fonts should always use the reference glyph for unmarked characters
>> > >(ignoring differences only of style). I think this is actually a
better
>> > >solution in practice; it avoids having to add selectors that would
>> > >usually be redundant, and that would interfere with normalisation.
>> > >It's also consistent with the Mongolian variant selectors, where
>> > >unmarked should mean the "first form".
>> >
>> > Boy, great minds to think alike. Mark Davis just proposed that in
>> > a paper to the UTC this week.
>> >
>> > Unfortunately. this is not a model that's always usable. Please
>> > read the section on phi for background.
>> >
>> > By adding a variation, we cannot restrict the glyph range for the
>> > unmarked character - Mongolian being an exception since the unmarked
>> > character's glyph range has been *explicitly* restricted from the
>> > outset to the standard positional forms.
>> >
>> > For VS1, the situation is different in that the glyph range of the
>> > *unmarked* character *also* includes the glyph identified by VS1.
>> >
>> > A./
>> >
>> >
This archive was generated by hypermail 2.1.2 : Sun Jan 27 2002 - 12:37:02 EST