Re: [w32] display international HELLO

[Kenichi Handa <handa@ni.aist.go.jp>]

In article <00d801c82732$0001dfb0$d5101252@JRWXP1>, "Richard Wordingham" <richard.wordingham@ntlworld.com> writes:

>>> 3. Compositions of Lao characters, (i.e. with the 'composition' string
>>> property) using the Code2000 font (the only fully working Lao font I 
>>> have),
>>> do not display properly, whether they are in the Lao or
>>> mule-unicode-0100-24ff charset.

> > I think it's a waste of time to learn composition mechanism
> > of Emacs 22.  It will be a lot improved in emacs-unicode-2.

> Are you talking of future work or the present state of emacs-unicode-2, as 
> in Emacs 23.0.60.0?

I'm talking about the future work, but the latest
emacs-unicode-2 code already contains half-done codes.

> Are you talking of applying the composition property, 
> or of the rendering of composed sequences?

I'm going to allow each font-backends to generate proper
composition information that will vary depending on a font,
instead of the current fixed way of composition.  So, On
Windows, perhaps the font backend can utilize uniscribe.  On
GNU/Linux, I have not yet decided what to do; using Pango,
using m17n-lib, or using a newly written code that directly
uses libotf or harfbuzz for OTF handling.  I think the last
choice will result in the fastest rendering.

> With the help of Jason Rumney I 
> got 23.0.60.0 to build and run on Windows XP, but the Lao compositions are 
> still displaying unreadably bizarrely.  Unfortunately the more thorough 
> application of composition in emacs-unicode-2 currently makes matters worse! 
> Before, one could easily if tediously avoid the composition mechanism.  For 
> example, to make a Lao closed syllable consonant-vowel sequence <ka>, in 
> Emacs 22.1 one can type d, space, delete, a.  The best I can find in Emacs 
> 23.0.60.0 is d, space, a, left, delete.  However, as soon as one moves the 
> cursor the characters compose and are then misdisplayed.

That is because of the auto-composition mechanism introduced
in emacs-unicode-2.  The problem is that the current fixed
composition is suitable only for a specific font (usually a
fixed-width terminal font).  Even on Windows, I think
there's a way to use BDF fonts distributed as intlfonts.  If
you use those fonts on Windows, the rendering should be
good.

---
Kenichi Handa
handa@ni.aist.go.jp