Superscript and Subscript Characters in General Use

[Marcel Schneider]

On 12 Jan 2017 08:35:24 +0200, Khaled Hosny wrote:
> 
> On Thu, Jan 12, 2017 at 12:24:29PM +0900, Martin J. Dürst wrote: 
> > On 2017/01/11 17:32, Richard Wordingham wrote: 
> > 
> > > The truly straight Unicode approach in HTML is to use 19⁄45. 
> > > Just entering those 5 characters into a text entry box in Firefox gave 
> > > me a properly formatted vulgar fraction. That is how vulgar fractions 
> > > are supposed to work. Unfortunately, one may need to avoid 'exciting 
> > > new fonts' in favour of those with a large, working repertoire. 

Even Times New Roman turned out to be obsolete from this viewpoint, while 
Cambria (and Consolas) do work. I should make a comprehensive overview on all 
fonts, perhaps in a dedicated article “Fraction Slash” on Wikipedia (that seems 
to have existed).

> > 
> > Just for the record: The vulgar fraction display also happened in 
> > Thunderbird (on Windows).

It doesnʼt work for me.

> > Firefox and Thunderbird use the same display 
> > engine. I have switched HTML display off, because I prefer to read all my 
> > mail in plain text,

This is one more reason to make plain text more performative and comprehensive.
But when an e-mail is written in HTML, turning it to plain text usually doesnʼt 
convert the HTML formatting to plain text markup. Usually, because just this is
what HyperMail does, which builds the Unicode Mailing List Archives. At least, 
the start of superscript is converted to a ^.

How do you deal with the loss of content information, such as stress, superscript, 
and so on?

> > but it still worked. 

It seems to me that in this use case, it will be even more likely to work, given 
that the plain text font of Firefox and Chrome (admitting that this is used in the 
text boxes of all websites) is up-to-date, while most font-families used for HTML 
arenʼt. Though I must find a way to update my system fonts.

> 
> This is done by HarfBuzz which automatically activates OpenType 
> frac/dnom/numr features for  sequences, 
> so if the font has the features one gets vulgar fractions out of box. 

According to Wikipedia (
https://en.wikipedia.org/wiki/HarfBuzz#Major_users
), HarfBuzz is included in LibreOffice too, but being on Windows, despite of 
having just installed the brandnew version 5.2.4.2, I still donʼt get it, since 
it comes with 5.3: 
https://wiki.documentfoundation.org/ReleaseNotes/5.3#Text_Layout

Thanks however!

Waiting for this, I shall probably stay inputting fractions as superscript-
subscript sequences, given that many fonts do have the appropriate glyphs for 
fractions mapped to the Unicode super/sub scripts, while application formatting 
for fractions (that I thought TUS is referring to) is available in desktop 
publishing software only, and the default super/sub formatting doesnʼt match 
requirements for vulgar fractions.

> This works in Chrome as well since it uses HarfBuzz (older version of 
> Chrome didn’t enable HarfBuzz by default for Latin so the fractions 
> might not show there). 

This raises a compatibility issue. Having tested my page on Chrome where I get the 
fractions right in some fonts like Cambria, Iʼm about to switch the default typeface 
from Tahoma to Cambria (or some other one, if I find another proportional font 
out there that does work as intended). But what will happen when somebody charges 
the page into another browser (Edge, Safari, Opera, IE)? 

I guess that the collateral damage (of being tagged as a careless and sloppy 
typographer) is minimized when I use a proven and stable feature like composing 
fractions following the 'U+00B9 U+2079 U+2044 U+2084 U+2085' pattern, compared 
with using the—really straightforward—'19 U+2044 45' pattern in its stead.

Therefore, Iʼm interested in learning for what reasons the widespread and thorough
implementation of a feature like the Unicode behavior of U+2044 FRACTION SLASH 
takes more than fifteen years — if it will ever be thoroughly implemented!

Regards,
Marcel