Re: LYNX-DEV Unicode support: charsets

[Drazen Kacar]

Klaus Weide wrote:
> On Wed, 4 Dec 1996, Drazen Kacar wrote:
> 
> > Klaus, I still don't know if console on OSF 4.0 can deal with Unicode or 
> > not,
> > but I've found out something else. I can't stand Linux only things :) Yur 
> > docs
> > say:
> > 
> >  - EXPERIMENTAL, currently enabled only for Linux console: 
> >    can (attempt to) automatically switch terminal mode and load new
> >    code pages on change of display character set.
> > 
> > The fact is that plain old xterm can do this. Here's the escape sequence:
> > 
> > ESC ] 5 0 ; "font name" BEL
> > 
> > For example:
> > 
> > ^[]50;-dec-terminal-medium-r-normal--14-140-75-75-c-80-iso8859-2^G
> > 
> > Only one code page at the screen can be active this way and xterm will
> > resize itself if the font size changes. There might be a way to have more
> > than one code page, but I think special fonts are needed for that. Xterm
> > can switch fonts, but only the lower 128 chars. Don't ask me why not the
> > higher ones as well. Esc codes exist, but xterm docs say that they have
> > no visible effect in xterm. I've checked, they don't. Even if this was
> > possible, there'd be big problems with curses package which wouldn't know
> > it should send some esc codes. I suppose you can bypass it somehow for
> > the initializating sequence.
> 
> If it switches only the lower 128 chars, it's of course useless for most
> cases.  All the differences between e.g. iso8859-1 and iso8859-2 are in 
> the upper 128 chars, and we probably always need the ASCII chars available.

Esc code that I posted will switch all 256 characters. There are other
codes that will switch just the lower half. You can have 3 or 4 of them
at the same time, and if you make fonts which will have the 128 halves
switched, it could work. No, I don't think this should be done. I was
just informing about the possibility.

> > But, there is another trick for color xterm. I didn't check this one out,
[...]

> For this to work, all use of bold in the current code would have to be
> weeded out.  Then all code that may turn bold OFF also would have to be
> changed, to not do this if the bold state is used for some other purpose
> than, err, bolding.  Well I'll gladly leave that to Rob if he wants to
> do this, or someone else...

I know. I don't think it would be implemented. But it's a nice post for
the archive. :)

> Frankly, I don't see much need for lynx-controlled codepage switching
> if Lynx is running in an xterm (or rxvt).  In that case you could

I don't know if it'll work on rxvt. There could be other perverse
possibilities there.

> always run another copy of Lynx in a different window, which could
> have any font you want.  You can have one window for viewing iso8859-1
> pages, another for iso8859-2, another for KOI8 etc. all at the same
> time (whereas the bold hack would probably give at most one
> alternative codepage), and you have a mouse to cut and paste URLs
> between the windows if necessary.  (I assume that if you have enough
> memory for running X you can also afford to run several copies of Lynx...)

The assumption is correct, as far as I'm concerned, but I'd like my
favourite browser to be able to switch code pages. Switching with the above
esc sequence should be easy enough, finding out which fonts are available
is not.

Although, having two code pages is nice sometimes.

> ideas...  But anyway the code for doing the switching is nearly
> self-contained and independent of the other chartrans code, it is just
> one function that gets called (hopefully..) in the right place and
> gets passed an argument indicating which character set to switch to.
> It is in a separate new file, UCAuto.c.  So it should be fairly easy
> for anybody who wishes to support this for another system, assuming
> there is a simple way (emit an escape sequence or run a system
> command) to do it on that system.

Yup. I've checked. I suppose I'll have to find someone who'll teach me
how to get list of available fonts from X server. And then... Lynx will
be as slow as Netscape on start up :)

-- 
Life is a sexually transmitted disease.

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