Proposal for BiDi in terminal emulators

Kent Karlsson via Unicode unicode at
Sat Feb 2 07:01:46 CST 2019

Den 2019-02-02 12:17, skrev "Egmont Koblinger" <egmont at>:

> the font. It's taken from EastAsianWidth (or other means, which we're
> working on:

Yes, that too:
FE0F ? VARIATION SELECTOR-16 = emoji variation selector

But the issue you refer to only deals with U+FE0F. There is also U+FE0E:
FE0E ? VARIATION SELECTOR-15 = text variation selector
which can make a character that is "default emoji" (which are wide)
into "text variant", often single-width, for instance:
1F315 FE0E ; text style;  # (6.0) FULL MOON SYMBOL


>> Likewise non-spacing combining characters should
>> be possible to deal reasonably with.
> Most terminal emulators handle non-spacing combining marks, it's a
> piece of cake. (Spacing marks are more problematic.)

Well, I guess you may need to put some (practical) limit to the number
of non-spacing marks (like max two above + max one below; overstrikes
are an edge case). Otherwise one may need to either increase the line
height (bad idea for a terminal emulator I think) or the marks start
to visually interfere with text on other lines (even with the hinted
limits there may be some interference), also a bad idea for a terminal
emulator. So I'm not so sure that non-spacing marks is a piece of cake...
(I.e., need to limit them.)

/Kent K

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