On Jan 28, 2008 3:17 AM, Arthur Reutenauer
Hello,
Thanks for this comprehensive review. If I'm not mistaken, there is no specific code for CJKV typesetting in Mark IV; the examples in mk.pdf seem to use the generic font loading mechanism.
This is wrong, fon-otf contains a few lua macros about linebreaking and char-def has information about the character width (full width, half width ...) and other information like opening punctuation, parenthesis but none of them is finished.
I would like to answer more completely, but don't have much time for the moment. About some of your remarks:
so I think a new feature should be added to map all the Chinese puncts into english while at the same time, a space should be added after the English punct marks.
Would it not be better to automatically add shrinkable glue after Chinese punctuation, rather than replacing the character by force? This would be very much in line with the general TeX philosophy of setting text (and would probably suppress the need for half-width forms in the font altogether).
- pp118, penultimate example, box 2, line1, the ' punct mark should not appear at the end of the line
This should be taken care of by adding an appropriate penalty before the character.
- pp118, ultimate example, box 2, line2, in fact, if you want do perfect Chinese typesetting, all the puncts which begin a line or end a line should be closed to the margin line
Do you mean simply closer to the margin, or in the margin itself (protruding)? Protruding is already possible in pdfTeX; I believe it is available in LuaTeX as well, although it might be broken for the moment (Taco?). Setting the character closer to the margin should be possible as well, as a modified form of protruding, I trust.
A small skip should be left between Chinese and English which makes the result much better. usually the space is a quarter of a chinese character width. A TeX expression should like: \hspace{0.25em plus 0.125em minus 0.08em}
Again, this can be taken care of by automatically adding this glue between pairs of character of the appropriate category.
The last important thing for English and Chinese bi-lingual typesetting is that: do not use English glyphs in Chinese fonts
Sure, there should be a possibility of specifying a Western font to be used inside Chinese text.
Could be done with cirtual fonts but we need a interface.
- the following script produce an error: Invalid field id penalty for node type glyph (1).
I don't have that error here. This is very big font; are you sure it has been read entirely and correctly written to the cache? Lua crashed on my machine when I first compiled your example, and only a partial font hash was written to the cache (ConTeXt didn't crash, so the first compilation apparently ended well, but the cache was already filled with a partial font). I can imagine that problems will arise in the presence of a partially hashed font in the cache.
Anyway, the code looks quite weird to me:
\definefontfeature[chinese][mode=node,script=hang,lang=zht,script=hani,lang=dlft]
This means that you activate two different scripts at the same time (hang == Hangul and hani == Han ideographs), and also two languages at the same time (zht == Chinese Traditional and dlft is probably a typo for dflt == default). I can't imagine what that is supposed to mean, and activating Traditional Chinese is probably wrong with Adobe Song Std which is a Simplified Chinese font. A saner definition of that feature would be in my opinion:
\definefontfeature[chinese-traditional][mode=node,script=hani,lang=zhs]
You need the hang script, it takes care about the linebreak.
I know this code comes from mk.pdf, but I think it is a mistake.
Finally, there is an interesting article by Jin-Hwan Cho (the dvipdfmx author) and Haruhiko Okumura about CJKV typesetting with Omega a couple of years ago. They have implemented all of the rules you mention above and a bit more; and although they used OTPs at the time, it should be quite straighforward to transpose it in Lua code (actually, I've done it a couple of months ago, but I have used plain LuaTeX, and in ConTeXt it should probably done using node processors or something).
This this currently done in font-otf.lua. Greetings, Wolfgang