Re: Pixel-based display functions

[Stephen J. Turnbull]

Eli Zaretskii writes:

 > > Among math symbols people may prefer different versions of some of
 > > them (cf TeX's \varphi, for example).
 > 
 > Not sure I understand the situation you describe here.

Run the string "\phi \varphi \epsilon \varepsilon" through TeX.  I
don't recall which fonts I had the issue with but there were two TTF
fonts that were quite similar to each other which each had one of the
variants I liked and one I didn't like.  So I wanted to create a
combined font; it turned out it wasn't possible at the within-face
level in XEmacs.

 > > Large character sets like Han (you may specify Japanese fonts
 > > because your audience is Japanese, but if your text contains Chinese
 > > names for example, you may need to borrow characters from a Chinese
 > > font).
 > 
 > I get quite a few spam mail with Japanese and Chinese characters in
 > them, but the former are always Kana, while the latter are Han.

I can't speak to the spam you receive, and you needn't bother saving
any for me, but I assure you I regularly get mail in Japanese language
encoded as UTF-8 from Chinese, which all consoles I have must mix
fonts to display all characters[1] because all of the Japanese fonts I
use lack many Han, because they are not part of the JIS standard.  I
appreciate being able to choose the fallback fonts in XEmacs rather
than using fontconfig configs.

Incomplete fonts are less of an issue for Chinese fonts, but I doubt
Handa-san will be sympathetic to an argument which deprecates
Japanese. :-)  Be that as is may, AIUI font mixing is not so useful
for Chinese. At least "traditional" fonts have a repertoire which more
or less includes the Japanese repertoire up to glyph variant issues
like \phi vs. ^varphi, and both "traditional" and "simplified" Chinese
fonts seem to all have Japanese kana in them.  In fact since the GB
18030 standard does "#include <Unicode>", at least simplified Chinese
fonts with full coverage in that standard should have all Unicode
characters ... I don't know if there are full- coverage fonts, but I
suppose there are.

Footnotes: 
[1]  It turns out that Chinese often input characters that are
unstandardized cognates of standard Japanese characters, so I can
mostly read them, and sometimes they use Chinese words that "should"
(and may, for all I know) translate directly to Japanese "cognates".
But display engines are more literal-minded and can't make those
substitutions based on glyph shape.