From: Doug Ewell (dewell@adelphia.net)
Date: Wed Aug 06 2003 - 18:24:35 EDT
Peter Kirk <peter dot r dot kirk at ntlworld dot com> wrote:
>> Or it may not. It may be a deficiency in the level of Unicode
>> support afforded by the fonts and rendering engines. ...
>
> If there are such deficiencies in fonts and rendering engines which
> purport to be Unicode compliant, that suggests a lack of clarity in
> the standard which should be rectified.
I wish I had a dollar for every "Unicode-compliant" font, rendering
engine, or other software that was in some way less compliant than
advertised. Only a fraction of the non-compliances are traceable to
ambiguities or deficiencies in the Unicode Standard.
>> ... It may simply reflect a difference between your "requirements"
>> and what the standard promises, and doesn't promise.
>
> If Unicode doesn't promise what I require, surely it is at least
> reasonable for me to ask on this list whether it ought to be extended
> or clarified to do so. The UTC may choose not to make any changes, but
> I don't see why they shouldn't even be asked to.
Absolutely, you are allowed to ask. Go ahead. I wasn't trying to
prevent questions from being asked, only trying to state why I think the
problem is out of scope for Unicode.
>> The standard doesn't say anything about width in this case. It
>> leaves it up to the display engine, which is as it should be.
>
> The standard does say, section 2.10 of 4.0, that "In rendering, the
> combination of a base character and a nonspacing character may have a
> different advance width than the base character itself".
I apologize for missing this reference.
> And any intelligent typographer will realise that this "may" is a
> "must", with regular character designs but not of course in monospace,
> in some cases like the example given of i with circumflex. This
> sentence applies to spaces with diacritics as space is a base
> character, as we have been informed. The subsection of 2.10 entitled
> "Spacing Clones of European Diacritical Marks" (by the way, why
> "European" when the text appears to apply to all diacritical marks?)
> should suggest to any intelligent typographer that the sequence space,
> diacritic is intended to be spaced as the diacritic and not as a
> space, but it would help for this to be clarified as not all
> typographers are very intelligent and some may not be aware that this
> space has actually lost most of the properties of a space e.g. line
> breaking and is being used only "By convention".
Like Freud's cigar, sometimes a "may" is just a "may." And I suspect
the phrase "any intelligent typographer" MAY generate some flak from
typographers on this list who consider themselves "intelligent enough"
yet have a different opinion.
I'm not a typographer (intelligent or otherwise), but I'm having a tough
time seeing how Section 2.10 *requires* fonts and rendering engines to
give a space-plus-combining-diacritic combination the exact minimum
width of the diacritic alone, or to leave equal space before and after
such a combination. All I think it is saying is that, for example, the
combination i-plus-tilde may be wider than i alone, because tilde is
wider than i.
>> When the specific alignment of isolated glyphs is important to me, I
>> use markup. I'm a big supporter of plain text, as many members of
>> this list know, but the exact spacing of isolated combining marks
>> seems like a layout issue to me.
>
> OK, what kind of markup should I use, in any well-known markup
> language, to ensure that an isolated diacritic is centred in the space
> between the words before and after it?
All right, you've got me there. I'll have to think about it. But I
still think this is a layout problem, a problem having to do with glyphs
and not characters.
-Doug Ewell
Fullerton, California
http://users.adelphia.net/~dewell/
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