[fpc-devel] fpcsrc/rtl/unix/video.pp

Tomas Hajny XHajT03 at mbox.vol.cz
Fri Nov 3 19:06:31 CET 2006

Daniƫl Mantione wrote:
> Op Fri, 3 Nov 2006, schreef Tomas Hajny:
>> This is something to be addressed in video.pp - we need to detect the
>> character set supported by console at startup (optionally with a
>> possibility to change it later on). This is something we partly touched
>> in
>> discussion with Daniel in Eindhoven (but I haven't managed to do
>> anything
>> regarding video.pp since then, unfortunately :-((( ). Ability to use
>> linedrawing characters directly depends on that, obviously.
> No, this is a different issue than we talked about in Eindhoven. In
> Eindhoven we talked about how FV should access line drawing characters.
> This is about how the video unit draws them.

Well, it's at least partly related to that discussion, IMHO - see below.

> Xterm supports two modes: ISO-8859-1 and UTF-8. There are two ways to use
> a different code page:
> * Put the xterm in ISO-8859-1 mode and just load a font with different
>   characters in #128..#255.
> * Use proper fonts, but use an emulator that switches the terminal into
>   UTF-8 mode and emulates a terminal with the desired encoding. I forgot
>   the name of the emulator.

UTF-8 mode should work, shouldn't it (as long as video unit can draw the
line drawing characters using their UTF-8 codes, of course)?

> The line in question enables the use of the vt100 alternate character
> set. You access the normal font by switching the terminal to the G0
> charactert set, and the ACS by switching it into the G1 character set.
> The ACS should be available when code page 1251 is in use.
> However, the video unit emulates a code page 850 on a iso-8859-1, using
> the ACS for the line-drawing characters. This doesn't work for Russian.
> As a short term solution a conversion table should be added from a
> Cyrillic Dos code page to 1251+ACS.

I don't think this is a reasonable solution. Why not to use translation
capabilities provided by the WideString manager? Otherwise you'd need to
implement translation tables for all the different pairs...


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