Thai/Devanagari in GNOME Terminal

[Chookij Vanatham <chookij vanatham eng sun com>]

Hi Owen, Robert,

] But a terminal is enough different from displaying normal text that I
] think trying to use the Pango layout APIs is going to be difficult.
] This does depend on your goals: a terminal that just handles shell
] commands is easy enough, but a terminal that can handle curses
] programs has to deal with positioning in a way that is very different
] from continuous text.
] 
] (I actually don't have much of a sense of how a terminal should
] behave in the presence of bidirectional and complex text, so
] I might be very wrong about this) 

Since I'm native Thai person, I can share some information about how
Thai script works in Terminal emulator.

In the past when we were using MS-DOS on PC under text-mode (not graphic
mode) for Thai, there were a lot of Thai terminal emulators which
were running as the resident program. These Thai terminal emulator
were taking care about Thai text rendering on the screen.

Those english tty-based applications were not needed to be modified
at all but they were able to use with Thai data and had Thai text
display correctly when users delete/insert Thai characters.
(as long as those tty-based applications are 8-bit clean).

So, we can say that all those tty-based applications are still
operating as character based (not the cell based) but terminal-emulator
itself, ie, gnome-terminal, etc. will be needed to manage Thai
rendering correctly. Let's say, the terminal is in 80 column and 25 rows
modes and tty-based application sends those escape-sequences to display
80 Thai characters and of course, some of them will be vowels, tonemarks,
then terminal-emulator will display those 80 Thai characters correctly
but there are some space left at the end of that line due to vowels,
tonemarks and that is ok for us. This is just the starting example.

In term of, bidrectional script like arabic/hebrew, I think we should
check how their bahaviors would be first. May be someone from native
language can give us more info like I did for Thai.

Once we have behaviors, then we should be able to see how we will be
able to use Pango APIs to do the works.

Like Robert says, it's not necesary to be highly complex, and,
at least, I will be able to use "vi" or other tty-based applications
running well with Thai/Arabic/Devanagari... in gnome-terminal.

Let me know what you think.

Chookij V.