[mosh-users] Alternate character set support (line grpahics) with terminfo

[Vincent Lefevre]

On 2014-03-20 16:17:37 +0100, Keith Winstein wrote:
> Unfortunately, old programs were already broken by the switch from
> octet-based ANSI terminal emulators to UTF-8-based ANSI terminal emulators.
> The switch to UTF-8 was a breaking change to the terminal control language.

I don't think so. Well, not in a significant way in practice.

> Compare:
> 
> LC_ALL=C xterm -e 'echo -e "\x9b44mHello... \x9b0;1m\x9b30Cworld!"; sleep
> 10'
> 
> [image: Inline image 1]
> 
> (The "LC_ALL=C" puts xterm in old-fashioned octet-based mode.)
> 
> to the same command, run in a UTF-8 terminal emulator:
> 
> LC_ALL=en_US.UTF-8 xterm -e 'echo -e "\x9b44mHello...
> \x9b0;1m\x9b30Cworld!"; sleep 10'
> 
> [image: Inline image 2]

On my machine there are just cosmetic differences.
See attached images.

> The escape sequence (using C1 CSI) works fine in an "original" xterm, but
> the switch to UTF-8 breaks this application.

I think that they are disabled in my xterm, as they are useless in
practice. IIRC, I had problems with them even in the pre-UTF-8 time,
because these code points were used by Microsoft so that one could
find them in text files in practice, and interpreting them as
control characters was a bad idea.

-- 
Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
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