Re: Numeric shaping in Pango

["Lina Kemmel" <LKEMMEL il ibm com>]

On Sun, 21 Sep 2003, Jungshik Shin wrote:

>>>Pango won't convert European digits to any other kind
>>>automatically. There are no rules anywhere (in Unicode for
>>>example) that say that should be done.
>>
>>Section 13.3 of http://www.unicode.org/book/ch13.pdf says:
>
>
>   It's section 15.4 (p. 395) in Unicode 4.0 if anyone is wondering.
>

Thanks for the updated reference.

>>"... the European digits (U+0030...U+0039) should be depicted
>>using glyphs that represent the nominal digits shapes shown
>>in the code tables for these glyphs. This state (nominal) is
>>the default state in the absence of any numeric shape
>>selector..." [deprecated, though] "...or a higher-level
>>protocol".
>
>
>   Without any agreement in advance,  numeric shape selectors
> would be almost useless (although a locale based selection might be
> possible), which is why I guess they were deprecated. Anyway, I believe
> blindly replacing [U+0030, U+0039] with other glyphs
> without any indication of the authorial intent (e.g. enclosing them with
> a pair of numeric shape selectors) is a bad idea.

I don't insist on "blindly replacing", glyphs substitution should occur in
conformance to the standards. BTW Technical Report 9 is pretty humane in
treating a "higher-level protocol"

- http://www.unicode.org/reports/tr9/tr9-11.html#Higher-Level_Protocols:

"...information from other paragraphs in a document could be used to
conclude
that the document was fundamentally Arabic, and that EN should generally be
converted to AN."
...
"Remap the number shapes to match those of another set.
For example, remap the Arabic number shapes to have the same appearance as
the European numbers." [or vice versa of course]

> If they want [U+0660, U+0669] or digits defined in several Indic script
> blocks, they could just them directly.

That's what should happen in the ideal world. In the real world, AFAIK
these characters are absent in most keyboard layouts (except maybe IBM
ones),
and I don't expect them to be widely used in the absence of a simple way to
input them.

Thanks,
Lina