Kubernetes helm symbol ⎈ (U+2388) should be single width

[gitfool]

Following up from microsoft/terminal#5893, it seems that the helm symbol ⎈ (U+2388) should be single width.

I can appreciate from a UI rendering POV, like with Visual Studio Code, it may well look better with double width. (Was that the reason for af1c556?) From both a Unicode standard and Terminal POV, however, it looks like the wrong choice.

I love this font as much as I love Kubernetes, so is there any chance this symbol could be reworked to be single width and thereby play nice with terminals? 😁

[tonsky]

I don’t understand. In the issue you link to, helm being small is the problem. You want me to make it even smaller?

[gitfool]

It's small in the Terminal because it's defined as double width in Fira Code but treated as single width based on the only information available to it; i.e. Terminal does not know any better since it can't consult the font info. So if Fira Code defines the symbol within a single width, as defined by other fonts and the Unicode standard, then the symbol will not get squeezed to fit in a single width space.

[tonsky]

Ah, I see! So Terminal doesn’t know how to render double-width chars? Ok but if I squeeze it into 1-width char it will be just as small as it’s displayed now. Would that work for you?

[tonsky]

Basically nothing will change :) Except in VS Code and other editors it will become small too

[DHowett-MSFT]

So, this is why I'm a bit concerned. Terminal well knows how to render double-width characters, but everything we can find on the matter suggests that U+2388 is supposed to be narrow. Here's what it says in the UCD.

PS> $ucd=[xml](gc .\ucd.nounihan.flat.xml)
PS> $helm=($ucd.ucd.repertoire.char | ? cp -eq 2388)
PS> $helm|ft cp,ea,Emoji,ExtPict

cp   ea Emoji ExtPict
--   -- ----- -------
2388 N  N     Y

With ea=N (neutral = narrow for non-ea) and emoji=N, we have nothing to go on to enforce it as being 2-wide.

emoji-sequences also doesn't contain it (even with a modifier that says it should be rendered wide.)...

[DHowett-MSFT]

(We unfortunately have to have a consistent definition of characters as 1 or 2 cells, like other terminal emulators, to make sure that connected text-mode applications have a consistent view of the screen buffer as us 😄)

[gitfool]

@tonsky it will still be small, yes, but it won't be scaled to be smaller than it should be, since both Fira Code and Terminal will agree on expected width. See microsoft/terminal#5893 (comment) for screenshots with a different font showing the helm character filling the cell for a single width character.

[gitfool]

Thinking about this some more, I guess it won't be scaled the way I was initially thinking, and the only thing Fira Code could do is to rework the symbol to look better given the constraints of a single width character. Sound right?

[tonsky]

@DHowett-MSFT That’s what I meant. Can’t have this from font info, as other people could be using other fonts and then columns will shift etc.

@gitfool There’s really not much design space to explore, as a circle is a circle. It will be just as small as all other circles, exactly 2x smaller than now and completely illegible. That’s what pushed me to make it 2-letter wide in the first place. I didn’t know about terminals limitations back then.

I will scale it down, but don’t expect miracles. It will look as crappy as it does in your second screenshot :)

Thanks for reporting!