Add visual indication to phantom space

[eranl]

Phantom spaces are very helpful, but they're also confusing, since there's no visual cue to their existence.

Is it possible to add some such indication? Maybe a changed cursor, a blinking space, or similar? For reference, Gboard displays it as a normal space.

I'd love to implement, with guidance.

[eranl]

Apparently, the cursor can't be changed, and no blinking is possible. Image span also doesn't seem to work. Setting a background color is possible, but not respected by all apps (not even by HeliBoard's own settings search). We can add an underline, which seems to work more generally. Or we can use both background color and underline, so that underline is the fallback.

[Helium314]

There seems to be quite a bunch of different Spans, is it possible to e.g. set a BulletSpan after the last character?
If Spans are not working reliably, the indicator may need to be on the keyboard (space bar?).

[eranl]

BulletSpan applies to a whole paragraph, so I don't think it would work.
I think we need @BlackyHawky's opinion again. 🙂
How would you indicate this on the space bar or elsewhere on the keyboard? Maybe change the space bar's color like the shifted shift key? Would that work in all color schemes?

Change the space bar text to one of these?
Auto-space
      Auto
└───┘
[Auto]
[🪄]
     🪄 
└─┘
[✩]
     ✩
└─┘

If #1803 is on, we could change the backspace key somehow, to indicate that pressing it will delete just the phantom space. Maybe shift its color?

[BlackyHawky]

Wouldn't it be better just to change the icon for the Delete key?

Indeed, I don't think it's a good idea to change the space bar because, in my opinion, after a phantom space, either a character is added or the phantom space is removed.
Maybe I'm wrong?