Re: "Final" version of tty child frames

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Gerd Möllmann <gerd.moellmann@gmail.com> writes:

> Gerd Möllmann <gerd.moellmann@gmail.com> writes:
>
>> Feng Shu <tumashu@163.com> writes:
>>
>>> Gerd Möllmann <gerd.moellmann@gmail.com> writes:
>>>
>>>> Feng Shu <tumashu@163.com> writes:
>>>>
>>>>> border do not work well when current buffer is CJK, maybe because CJK
>>>>> Char width is not 1
>>>>
>>>> Could you please send me a bit of CJK text so that I have something I
>>>> can test this with?
>>
>> Thanks!
>
> Hm, okay, but not sure how to fix that.
>
> The problem comes indeed from the root frame displaying characters that
> are more then 1 column wide, say N. When we output such a character to
> the terminal, the cursor moves by N columns. Emacs represents that in
> the glyph matrix by producing N glyphs for the character, all bu tthe
> first have a padding flag set. So we have
>
>   ... (C, 0) (C, 1) ...
>
> in the glpyh matrix, where C is the character, and the number is the
> padding flag.
>
> Now assume, for example, that the child frame is posititoned so that its
> left border where we want to display a '|' is in the column for the (C,
> 1).
>
> That can't work, because writing C to the terminal moves 2 columns and 
> will skip over the column where we want the '|' to appear.
>
> I think the same should happen, in principle, without borders. Haven't
> checked that though. Maybe we have to "clear the field" to the left and
> right of child frames in the root frame matrix so that wide characters
> don't interfere.

Another question is if there is something lurking with R2L? I have no
idea what terminals do in that case, but I'd guess Eli knows :-).